JP6338725B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article, and more particularly to an absorbent article that is excellent in both liquid permeability and liquid uptake, fits between the crotch, has excellent wearing feeling, and is excellent in preventing liquid leakage.

  Absorbent articles such as incontinence pads, sanitary napkins and disposable diapers usually have a structure in which an absorbent that absorbs body fluid is disposed between a permeable top sheet and an impermeable back sheet. The wearability and body fluid absorbability of articles largely depend on the structure and constituent materials of the absorber.

  For the purpose of efficiently capturing and confining body fluids in absorbent articles such as disposable diapers, it has an acquisition zone made of pulp fibers in the vicinity of the excretion opening and a storage zone made of pulp fibers around it, and the acquisition zone and Disclosed is an absorbent article comprising an absorbent layer formed by laminating an absorbent layer made of pulp fibers on a storage zone, and an average density and basis weight of the acquisition zone being lower than that of the storage zone and having an absorbent body having a lower basis weight. (Patent Document 1).

  In the absorbent article of Patent Document 1, the acquisition band has a low average density and a low basis weight, and thus has liquid permeability. However, since the acquisition band uses the same fiber pulp as the storage band, the liquid transmission Proposed an absorber comprising a tow region composed of a fiber assembly made of tow and a thickness maintaining region made of an absorbent material other than tow and having a smaller compression work (WC) than that of the tow region. (Patent Document 2).

  Moreover, in the absorbent article of patent document 2, although the upper layer tow | bowl raises liquid permeability, the part used as the lower layer liquid permeation | transmission channel | path is filled with a liquid, and the liquid permeation from an upper layer with respect to a new excretion liquid after that. In order to maintain the liquid uptake, the liquid holding part using pulp fibers, and the liquid holding part is weaker than the liquid holding part and has a hydrophilic liquid permeation part. There has been proposed an absorbent core in which the liquid permeation part is composed of a non-woven fabric made of a chemical fiber or the like (Patent Document 3).

Japanese Patent No. 2635599 (Japanese Patent Laid-Open No. 63-109859) JP 2006-014886 A JP 2014-113273 A

  As described above, in the absorbent article of Patent Document 1, since all regions of the absorbent body including the acquisition zone and the storage zone are composed of pulp fibers, liquid permeability in the acquisition zone and from the acquisition zone to the storage zone Not only is the liquid transfer not sufficient, but the voids in the acquisition zone are crushed by body pressure, and the effect of improving the absorption rate cannot be expected, and the compressibility, deformability and compression recovery properties, and the deformation recovery properties are poor. In addition, there is a drawback that the fit at the time of wearing is inferior, there is a sense of incongruity, and it also causes liquid leakage.

  In the absorbent article of patent document 2 and patent document 3, it is excellent in liquid permeability in the tow | toe area | region comprised by the fiber assembly which consists of a tow | toe, and a liquid permeation part which consists of chemical fiber and has a weak liquid retention power and is hydrophilic. However, because the toe region and the liquid permeation part are arranged so as to be exposed on the skin side surface of the absorbent body, the liquid drawing from the top sheet to the absorbent body is weak, so that the body fluid remains on the top sheet and feels wet There is a problem that the feeling of wearing decreases.

  Accordingly, the present invention provides an absorbent article that solves the problems of the background art described above, is excellent in both liquid permeability and liquid uptake, fits between the crotch, has excellent wearing feeling, and is excellent in preventing liquid leakage. For the purpose.

  As a result of intensive studies to solve the above problems, the present invention arranges a low-density skeleton layer containing a water-retaining material near the excretion opening, and arranges a normal absorbent core layer on both sides in the width direction, It has been found that the above problem can be solved by using an absorbent material in which an absorbent material layer having a higher hydrophilicity than the low density skeleton layer is disposed immediately above the low density skeleton layer, and the present invention has been completed.

And this invention includes the following aspects.
(Aspect 1)
A liquid-permeable top sheet disposed on the skin contact surface side, a liquid-impermeable back sheet disposed on the non-skin contact surface side, and a liquid interposed between the top sheet and the back sheet An absorbent article comprising a retaining absorbent and having a longitudinal direction and a width direction,
In the width direction, the absorbent body has a width direction center portion extending in the center in the length direction in the center, and width direction side portions extending in the length direction in both sides of the width direction center portion. The absorbent body is partitioned in the longitudinal direction in the longitudinal intermediate region and extends in the entire width in the width direction, and the width in the width direction on both sides of the lengthwise intermediate portion. Is divided into both longitudinal ends extending to
The absorbent body has 1) a central absorbent core upper layer on the surface sheet side of the longitudinal intermediate portion and both longitudinal end portions in the central portion in the width direction, and 2) the longitudinal portions on both side portions in the width direction. And having both side absorbent core layers adjacent to the central absorbent core upper layer on the surface sheet side of the intermediate portion in the direction and both ends in the longitudinal direction, and 3) the central portion in the width direction and the longitudinal direction of the intermediate portion in the longitudinal direction At least at the width direction central part of the both ends in the direction, it has a low density skeleton layer containing a hydrophilic fiber having crimps and a water absorbing material, and the low density skeleton layer is at least at the width direction central part. In the middle part in the longitudinal direction, the upper part is present on the back sheet side in contact with the central absorbent core upper layer,
The low-density skeleton layer has a density smaller than the density of each of the central absorption core upper layer and the both-side absorption core layers, and the low-density skeleton layer has at least a thickness of the middle portion in the longitudinal direction of the both-side absorption cores. An absorbent article having a thickness greater than the thickness of each of the layers, wherein the central absorbent core upper layer has a basis weight that is less than the basis weight at the longitudinally intermediate portion of the side absorbent core layers.

  (Function and effect) Since the low-density skeleton layer in the central portion in the width direction which is the position of the excretion contains hydrophilic fibers having crimps, a net-like bulky space between the fibers is formed, and the bulk is low and the density is low. Therefore, it is excellent in liquid permeability, has an effect of improving the absorption rate, and the fiber is hydrophilic, so that the liquid can be temporarily stored. At least in the longitudinal intermediate portion including the excretion opening position, and optionally at both longitudinal end portions on both outer sides of the longitudinal intermediate portion, a central absorbent core upper layer (hereinafter also simply referred to as an absorbent core upper layer) is formed on the low-density skeleton layer. ) And the liquid can be drawn from the top sheet. The drawn liquid is absorbed by the upper layer of the absorbent core, and the liquid that is not absorbed passes through and moves to the low-density skeleton layer below the upper layer of the absorbent core. Thereafter, the liquid temporarily stored in the low-density skeleton layer is drawn by the both-side absorbent core layers disposed on both sides of the low-density skeleton layer, and the liquid is gradually held in the both-side absorbent core layers. At this time, since the liquid in the low-density skeleton layer disappears and the voids are regenerated, the absorption can be repeated. Since a small amount of liquid remaining in the low density skeleton layer is absorbed by the absorbent material, rewetting is reduced, and even if the liquid permeates again into the low density skeleton layer, no liquid remains in the gaps between the fibers. Therefore, the liquid can be temporarily stored repeatedly. In addition, the low-density skeleton layer is formed thicker than the absorbent core layers on both sides, and the absorbent article has a medium-high structure and good cushioning properties. This prevents the liquid from leaking through the gap. In addition, since the both side absorbent core layers have a higher density than the low density skeleton layer, it is possible to maintain the bulk even under body pressure, and the both side absorbent core layers support (pillars) and have a low density. The skeletal layer is not easily crushed, the gaps between the fibers of the low-density skeleton layer are maintained, and the absorption rate can be maintained repeatedly. In addition, at least in the longitudinal intermediate portion including the excretion opening position, and optionally in both longitudinal end portions on both outer sides of the longitudinal intermediate portion, the low density skeleton layer is in contact with the low density skeleton layer on the upper layer of the low density skeleton layer. Compared to the absorbent core upper layer, which has a higher density, the liquid remaining on the surface sheet and the liquid flowing through the surface sheet can be drawn in. This can also be reduced when the wearer is in a sideways state. Further, rewetting due to the liquid overflowing from the low density skeleton layer is also reduced because of the upper layer of the absorbent core. Since the absorbent core upper layer has a basis weight smaller than the basis weight of both side absorbent core layers, the liquid is more easily permeable through the absorbent core upper layer than both side absorbent core layers, and the liquid to the low-density skeleton layer through the absorbent core upper layer It can be excellent in permeability.

  In addition, the low-density skeleton layer composed of hydrophilic fibers having crimps is thicker than the absorbent core layers on both sides, so that it adheres to the vicinity of the excretion opening and has a large compression work WC value. It is easy to be deformed, and when worn on the crotch, both sides of the width direction are pushed and the center part is deformed to become familiar with the body, so it fits the body according to the individual wearer (not uniform) Can be formed. Therefore, it feels soft and uncomfortable during wearing, and it is fit, so it is effective in preventing leakage. Furthermore, since the low density skeleton layer can maintain the skeleton structure even after absorbing the body fluid, it has good compression recovery and is difficult to twist. Therefore, the crotch width does not remain narrow and the absorption area can be maintained, which is also effective in preventing leakage.

(Aspect 2)
The central absorbent core upper layer has a density smaller than the density of the both side absorbent core layers, the central absorbent core upper layer has a thickness smaller than the thickness of the both side absorbent core layers, and the central absorbent core upper layer Is an absorbent article according to aspect 1, having a basis weight smaller than the basis weight in at least the intermediate portion in the longitudinal direction of the low-density skeleton layer.
(Function and effect) Since the absorption core upper layer has a density smaller than the density of both side absorption core layers and a small thickness, the absorption core upper layer allows liquid to permeate more easily than both side absorption core layers, and the low density through the absorption core upper layer Excellent liquid permeability to the skeleton layer. Moreover, since both side part absorption core layers have a density larger than an absorption core upper layer and a large thickness, while being excellent in the performance which draws a liquid from a low density frame | skeleton layer, the force which supports a low density frame layer is large. Since the absorbent core upper layer has a basis weight smaller than the basis weight at least in the longitudinal middle portion of the low-density skeleton layer, the liquid drawn from the topsheet is not absorbed much by the absorbent core upper layer, but permeates and is absorbed. Move to the low density skeletal layer underneath.

(Aspect 3)
In the aspect 1 or 2, the low-density skeleton layer is present on the back sheet side in contact with the central absorbent core upper layer in the widthwise central portion of both the longitudinal intermediate portion and both longitudinal end portions. The absorbent article as described.
(Function and effect) Since the low-density skeleton layer is present on the back sheet side in contact with the central absorbent core upper layer not only in the middle part in the longitudinal direction but also in the longitudinal direction at both ends, the density is low at the excretory mouth position. The liquid drawn into the skeletal layer can act as a liquid drawing in cooperation with both side absorption core layers at the far ends in the longitudinal direction, and further with the central absorption core upper layer.

(Aspect 4)
In at least one of the both ends in the longitudinal direction, the low-density skeleton layer continuously extends from the central portion in the width direction and also extends to both sides in the width direction. It exists on the back sheet side in contact with both side absorption core layers, and the maximum dimension in the width direction of the low-density skeleton layer at the at least one of the both ends in the longitudinal direction is the low-density skeleton layer in the intermediate portion in the longitudinal direction. The basis weight of the low-density skeleton layer in the at least one of the both ends in the longitudinal direction is smaller than the basis weight of the low-density skeleton layer in the intermediate portion in the longitudinal direction. The absorbent article according to any one of the above.
(Function / Effect) Since the low-density skeleton layer is widened and the basis weight is reduced in at least one end portion in the longitudinal direction of the absorbent article as compared with the intermediate portion in the longitudinal direction, the thickness of the bulky low-density skeleton layer is reduced. Can be thinned on the abdomen or buttocks side of the body, reducing the feeling of discomfort. If the low-density skeleton layer extends so as to overlap the both-side absorption core layers on both sides in the width direction, the material of the both-side absorption core layer and the low-density skeleton layer there will be entangled and the absorber will be prevented from losing its shape. In addition, since the low-density skeleton layer extends so as to overlap the absorbent core layers on both sides, the area of the absorber is more effectively used and effective in preventing leakage.

(Aspect 5)
In the low density skeleton layer, the hydrophilic fibers are entangled with each other in a net shape, and the water absorbing material is supported between the hydrophilic fibers entangled in the net shape. The absorbent article according to item 1.
(Function and effect) In the low-density skeleton layer, hydrophilic fibers are entangled in a net shape so that the water-absorbing material can be held, and the hydrophilic fibers are not joined together, so the hydrophilic fibers prevent the water-absorbing material from swelling. The water absorption of the water absorbing material is more exhibited.

(Aspect 6)
The absorbent article according to any one of aspects 1 to 5, wherein the hydrophilic fibers are continuous filaments of the tow opened, and the continuous filaments of the opened tow are arranged in the longitudinal direction.
(Function and effect) In the low-density skeleton layer, it is a continuous filament of tow in which hydrophilic fibers are opened, and since the continuous filaments of opened tow are arranged in the longitudinal direction, they are absorbed and continuously in the low-density skeleton layer. It is promoted that the liquid temporarily held in the gap between the filaments is diffused in the longitudinal direction along the continuous filament. In addition, when the diffusion of the liquid in the longitudinal direction is promoted, the transition of the liquid from the low-density skeleton layer to the both-side absorbent core layer is accelerated as a whole, so that the wearer of the absorbent article is in a lateral state The effect of preventing leakage of body fluid and preventing rewet becomes remarkable.

(Aspect 7)
The absorbent article according to aspect 6, wherein the low-density skeleton layer extends to both ends in the longitudinal direction of the absorbent body, and the continuous filaments of the opened tow exist up to the both ends of the absorbent body. .
(Function and effect) Since the low-density skeleton layer extends to both ends in the longitudinal direction of the absorbent body, and the continuous filaments of the opened tow extend to both ends in the longitudinal direction of the absorbent body, the low-density skeleton layer The action in which the liquid absorbed in the layer is diffused in the longitudinal direction along the continuous filaments of the tow opened acts over the entire length of the absorber. As a result, the diffusion of the liquid in the longitudinal direction is more strongly promoted, and the transition of the liquid in the aspect 4 from the low-density skeleton layer to the both side absorption core layers is more remarkably accelerated.

(Aspect 8)
The absorbent article according to any one of aspects 1 to 7, wherein the water-absorbing material contained in the low-density skeleton layer is not fixed with an adhesive.
(Function and effect) Since the water absorbing material is not fixed with the adhesive, the water absorbing material generated when the water absorbing material is fixed with the adhesive does not hinder the flow of the liquid or the absorption of the liquid.

(Aspect 9)
Each of the both side absorbent core layers and the central absorbent core upper layer includes pulp fibers and a superabsorbent polymer, and the hydrophilicity of the hydrophilic fibers contained in the low density skeleton layer is greater than the hydrophilicity of the pulp fibers. The absorbent article according to any one of aspects 1 to 8, which is low.
(Function and effect) Both side absorption core layer and absorption core upper layer contain pulp fiber and water-absorbing polymer, so that pulp fiber has high hydrophilicity (official moisture content), and water-absorbing polymer has a large water absorption per mass. Moreover, since the gel strength is also high, the both side absorption core layer and the absorption core upper layer are excellent in the performance of drawing the liquid from the surface sheet and the performance of holding the liquid. The hydrophilic fibers contained in the low-density skeleton layer have affinity with the liquid, but the hydrophilicity (official moisture content) is lower than the pulp fibers contained in the absorbent core layer on both sides and the absorbent core upper layer. The liquid taken into the layer easily moves to the both side absorbers, and no liquid remains in the low-density skeleton layer, so that rewet can be reduced.

(Aspect 10)
The absorbent article according to any one of aspects 1 to 9, wherein the water-absorbing material is a highly water-absorbing polymer.
(Effect) When the water-absorbing material is a highly water-absorbing polymer, the amount of water absorption per mass is large and the gel strength is high. Therefore, it is possible to maintain the voids of the low-density skeleton layer and maintain repeated absorbability.

(Aspect 11)
The absorbent article has a pressing groove extending from the top sheet to the both side absorption core layers, and the pressing groove extends in the longitudinal direction at both sides in the width direction. Absorbent article as described in 1.

  (Function and effect) The compressed groove (hinge) extending from the surface sheet to both side absorbent core layers extends in the longitudinal direction in both side absorbent core layers in the width direction instead of the low-density skeleton layer in the width center. Thus, since the absorbent body maintains the shape of the low-density skeleton layer, the absorbent article does not lose its shape, retains its performance, and is rich in cushioning properties.

(Aspect 12)
The absorbent article according to any one of aspects 1 to 11, wherein the density of the central absorbent core upper layer is greater than the density of the topsheet and the density of the low-density skeleton layer is less than the density of the topsheet.
(Function and effect) Since the density of the upper layer of the absorbent core is larger than the density of the surface sheet, the liquid absorbability from the surface sheet to the upper layer of the absorbent core can be excellent. Since the density of the low-density skeleton layer is smaller than the density of the topsheet, liquid permeability is imparted to the upper absorbent core layer and the entire low-density skeleton layer in the center in the width direction.

(Aspect 13)
The center absorbent core upper layer has a cushion layer between the top sheet and the absorber, and the density of the low-density skeleton layer is smaller than the density measured by integrating the top sheet and the cushion layer. The absorbent article according to any one of Embodiments 1 to 12, wherein the density of is high.
(Effect) When a cushion layer is provided between the top sheet and the absorbent body, the density of the low-density skeleton layer is smaller than the average density measured by integrating the top sheet and the cushion layer, and the density of the upper layer of the absorbent core is Since it is large, even when it has a cushion layer under the surface sheet, the liquid permeability of the low-density skeleton layer described in the embodiment 10 and the liquid absorbability of the absorbent core upper layer can be excellent.

(Aspect 14)
The absorbent article according to any one of aspects 1 to 13, which is an incontinence pad or a sanitary napkin.
(Effects) Incontinence pads or sanitary napkins are relatively small in size compared to disposable diapers, and because they are attached in close contact with the excretion opening, they can absorb more excretion faster and repeatedly. However, the absorbent article of the present invention is excellent in liquid absorbability, liquid leakage prevention properties, and wearing feeling, and is suitable for this application.

  The absorbent article of the present invention is excellent in both liquid permeability and liquid uptake, fits in the crotch, has excellent wearing feeling, and is excellent in preventing liquid leakage.

FIG. 1 is a partially broken perspective view of an incontinence pad 1 according to the first embodiment. FIG. 2 is a schematic plan view of the absorber 4 of the incontinence pad 1 shown in FIG. FIG. 3 is a schematic end view of the absorber 4 of FIG. 2 at the III-III end surface. FIG. 4 is an electron micrograph showing a state in which SAP is dispersed and held in a continuous filament of opened tow. FIG. 5 is a schematic plan view of the incontinence pad 1 of the first embodiment. FIG. 6 is a schematic end view of the incontinence pad 1 of FIG. 5 at the VI-VI end surface. FIG. 7 is a schematic plan view of the absorbent body 4 of the incontinence pad 1 according to the second embodiment. 8A and 8B are schematic end views of the absorbent core 41 at the end of the absorbent body 4 in FIG. FIG. 9 is a schematic plan view of the incontinence pad 1 of the second embodiment.

(Aspect of absorbent article)
The 1st embodiment of the absorptive article of the present invention is described with reference to drawings (Drawing 1-Drawing 6). FIG. 1 is a perspective view showing an incontinence pad 1 which is a first embodiment of the absorbent article of the present invention, but is partially broken. Referring to FIG. 1, the skin contact surface side of the incontinence pad 1 is visible, the liquid contact surface sheet 2 on the surface of the skin contact surface side, and the non-skin contact on the opposite side of the skin contact surface side surface It has a liquid-impermeable back sheet 3 on the surface side surface, and an absorbent body 4 is arranged between the top sheet 2 and the back sheet 3.

  FIG. 2 shows a plan view of the absorbent body 4 of the incontinence pad 1 of FIG. The absorbent body 4 has a longitudinal direction L and a width direction W perpendicular to the longitudinal direction, and a thickness direction perpendicular to a plane formed by the longitudinal direction L and the width direction W. Referring to FIG. 2, the absorbent body 4 has an hourglass shape with a reduced width in the vicinity of the center in the longitudinal direction L. The outer edge of the absorbent body 4 is a joining region of the core wrap 42 covering the absorbent core, and the absorbent core 41 is present inside the outer edge. The absorbent core 41 is divided into a center in the width direction W, a width direction center portion 4C extending in the longitudinal direction, and width direction both side portions 4S extending in the length direction on both sides of the width direction center portion 4C.

  In addition, in the absorbent body of the absorbent article of the present invention, the central portion 4C in the width direction and both side portions 4S in the width direction are defined as regions that divide the absorbent body. In the absorbent body, the width direction central portion 4C and the width direction both side portions 4S are about 20 mm to 70 mm, preferably 40 to 50 mm in width, with the width direction center line Lc as the center, and the width direction center portion 4C. Both side portions 4S in the width direction are used. The width of each side portion 4S in the width direction may be 10 mm or more. The upper limit of the width of each side portion 4S in the width direction may be the remaining dimension in which the center portion 4C in the width direction is appropriately formed from the entire width of the absorber. The dimension in the width direction of the absorbent body is about 50 to 120 mm in the vicinity of the center in the length direction corresponding to the crotch. The width of the central portion 4C is defined according to the width of the subject's crotch, and the outside is defined as both sides. To do.

  In the following description of the first embodiment and the drawings, for the sake of convenience, the width direction central portion 4C and the width direction both side portions 4S are combined with the low-density skeleton layer and the central absorption core upper layer and both side absorption core layers in the absorption core 41. It is expressed as a segmented area.

  Further, in FIG. 2, the absorbent body 4 of the absorbent article includes, in the longitudinal direction L, a longitudinal intermediate portion 4M including a full length intermediate region and extending in the full width direction, and both end portions outside the longitudinal intermediate portion 4M. It is divided into both longitudinal ends 4E. The longitudinal intermediate portion 4M includes a portion corresponding to the excretion port position in the longitudinal direction, and is a region having a dimension of about 50 mm to 200 mm, preferably about 80 to 180 mm. If the dimension in the longitudinal direction of the longitudinal intermediate portion 4M is less than 50 mm, the fit property is lowered. Since the center of the excretion port position is not necessarily the center (center) in the longitudinal direction of the absorbent body, the longitudinal intermediate portion 4M may be unevenly distributed on either the front or back side of the absorbent body. Further, it is not necessary that the longitudinal dimensions of the longitudinal both ends 4E are the same. Each longitudinal dimension of the longitudinal both ends 4E may be 10 mm or more, and may be a remaining dimension that appropriately defines the position and dimension of the longitudinal intermediate part 4M from the entire length of the absorber. The total length of the absorbent body in the longitudinal direction is determined by the type of absorbent article such as incontinence pad, sanitary napkin, and size thereof, and is generally about 150 to 400 mm.

  However, in the first embodiment, each of the low-density skeleton layer, the central absorbent core upper layer, and both side absorbent core layers has a width over the entire length of each of the width-direction center portion 4C and the width-direction side portions 4S. It extends only to the center in the direction or both sides in the width direction, and in particular, the low-density skeleton layer also extends only to the center in the width direction over the entire length and does not extend to both sides in the width direction. The intermediate portion 4M and the longitudinal both ends 4E have no particular distinction, and in the description and drawings of the first embodiment below, as a low density skeleton layer, a central absorbent core upper layer, and both absorbent core layers. write.

  In the second embodiment, the longitudinal both ends 4E are meaningful in defining a region in which the width of the low-density skeleton layer is wider at the longitudinal both ends 4E than at the longitudinal middle 4M. The region where the width of the low density skeleton layer is wider than the width in the longitudinal intermediate portion 4M can be either one of the longitudinal end portions 4E, and in the first embodiment, both longitudinal ends. Neither part 4E is widened.

  FIG. 3 is an end view of the absorber 4 in FIG. 2 at the III-III end surface. The absorbent body 4 includes an absorbent core 41 having absorbency and water retention, and a core wrap 42 that covers the absorbent core 41. 3, the upper side of the figure is the skin contact surface side with the top sheet 2, and the lower side is the non-skin contact surface side with the back sheet 3. There are width direction side portions 4S on the left and right sides of the width direction central portion 4C. In addition, the pressing groove is abbreviate | omitted in FIG. The absorbent core 41 covered with the core wrap 42 has an absorbent core on the low-density skeleton layer 411 on the non-skin surface side of the central portion 4C in the width direction and on the low-density skeleton layer 411 of the central portion 4C in the width direction, that is, on the skin surface side. The upper layer 412 and the both side absorption core layers 413 are provided on the respective sides of the width direction both sides 4S. In the present embodiment, the low-density skeleton layer 411 and the absorbent core upper layer 412 extend over the entire length of the absorbent core 41 in the longitudinal direction L at the center portion 4C in the width direction shown in FIG. 413 is extended over the full length of the absorption core 41 in the longitudinal direction L in the width direction both sides 4S shown in FIG. In the following, for the sake of simplicity, the “central absorbent core upper layer” is abbreviated as “absorbent core upper layer”.

  In the incontinence pad of this embodiment, the absorbent body 4 shown in FIG. 1 to FIG. 3 has an absorbent core upper layer 412 on the surface sheet 2 side of the width direction central portion 4C, and the absorbent core upper layer 412 at the width direction central portion 4C. Both side absorbent core layers 413 adjacent to both sides in the width direction of the low density skeleton layer 411 and the absorbent core upper layer 412 on both sides 4S in the width direction. The low density skeleton layer 411 contains hydrophilic fibers having crimps and a water absorbing material, and the low density skeleton layer 411 has a density smaller than the density of the absorbent core upper layer 412 and both side absorbent core layers 413. The low-density skeleton layer 411 has a thickness larger than the thickness of both side absorbent core layers 413, and the absorbent core upper layer 412 has a basis weight smaller than the basis weight of both side absorbent core layers 413.

  In the incontinence pad of the present embodiment, it is preferable that the width ratio between the width direction central portion 4C and the width direction both side portions 4S is 20 to 60:40 to 20. If the width of the central portion 4C in the width direction is too small, the ability to permeate the excreted liquid will be insufficient, and the liquid will remain on the top sheet 2, causing a sense of incongruity or liquid leaking from the top sheet 2. Yes, the effect of the present invention is reduced, which is not preferable. If the width of the central portion 4C in the width direction is too large, the amount of the absorbent core of the both-side absorbent core layer 413 is reduced, so that the absorption performance as the entire absorbent body is lowered, and the low-density skeleton layer 411 is easily crushed. The effect of the present invention is reduced, which is not preferable.

  In the present embodiment, the low-density skeleton layer 411 and the absorbent core upper layer 412 in the center in the width direction extend along the entire length of the absorbent body 4 and the entire length of the absorbent core 41 excluding the core wrap. As the hydrophilic fiber having crimps constituting 411, long fibers (fiber length of 70 mm or more), in particular, a continuous filament of opened tow is preferred. However, the low-density skeleton layer 411 and the absorbent core upper layer 412 do not extend along the entire length of the absorber 4 and the absorbent core 41, but exist only in the central portion in the length direction of the width direction central portion 4C. Both ends in the length direction of the central part 4C are provided with the same or similar absorption core layers as the both side absorption core layers 413, and the surrounding four directions of the low density skeleton layer 411 and the absorption core upper layer 412 are surrounded by the absorption core layers. It may be. Further, in this embodiment, the absorbent body 4 extends over almost the entire length of the incontinence pad. However, particularly in the case of a disposable diaper or the like, the absorbent body 4 exists only in a part of the full length of the absorbent body, particularly in the central portion in the length direction. May be.

  Moreover, the shape of the absorber 4 may be an hourglass shape or a gourd shape, or may be a rectangle or an ellipse.

(Low density skeleton layer)
In the incontinence pad of this embodiment, the low-density skeleton layer 411 is on the back sheet 3 side in contact with the absorbent core upper layer at the width direction central portion 4C of the absorbent body 4 and extends in the longitudinal direction L.
(Hydrophilic fiber with crimp)
The hydrophilic fibers having crimps used for the low-density skeleton layer 411 can be selected from known hydrophilic fibers used for an absorbent body of an absorbent article including an incontinence pad. Here, the hydrophilic fiber is not only the fiber material itself having hydrophilicity, but also the fiber material itself has no hydrophilicity, but may be one having hydrophilicity imparted by hydrophilic treatment. The hydrophilic nature of the fibers makes it possible to draw liquid and hold it primarily.

  As the hydrophilic fiber, any of natural fiber, synthetic fiber, semi-synthetic fiber and regenerated fiber may be used, but as natural fiber, pulp, etc., as synthetic fiber, polyamide fiber, polyester fiber, acrylic fiber, etc., as semi-synthetic fiber Examples of regenerated fibers such as rayon and cupola include acetate.

  In the incontinence pad of the present embodiment, if the hydrophilic fibers of the low-density skeleton layer are hydrophilic fibers having crimps, the low-density skeleton layer can be constituted, but the material constituting the both-side absorption core layer, Typically, fibers having a liquid holding power lower than that of pulp fibers are suitable. Accordingly, the hydrophilic fibers of the low density skeleton layer are preferably hydrophilic fibers other than pulp fibers. The difference in liquid retention of hydrophilic fibers between the absorbent core layer on both sides and the low-density skeleton layer not only improves liquid permeability in the low-density skeleton layer, but is also primarily retained in the low-density skeleton layer. This is because the speed at which the liquid is transferred to the both-side absorption core layer can also be improved. The strength and weakness of the liquid retention of the fiber can be evaluated by the official moisture content of the fiber. The method for measuring the official moisture content of fibers is stipulated in Japanese Industrial Standard JIS L0105: 2006 (General rules for physical test methods for textile products) (corresponding ISO 139: 2005), and the official moisture content of various fibers has been announced. Yes.

  In the present invention, the term “fibers have crimps” means that, in addition to the state in which the fibers are shrunk and wound, there are larger voids between the fibers than in the state in which the fibers are simply deposited, such as a state in which the fibers are entangled. A state (structure) formed. Although it is not necessary for the fibers having crimps to be bonded together by fusion or an adhesive, they may be bonded. When the fibers are crimped, gaps are formed between the fibers, so that the fibers are bulky and light (low density), and the liquid permeability is improved. In addition, since the elasticity and elasticity are improved, the fit of the incontinence pad is improved, so that not only the wearing feeling is improved, but also liquid leakage is prevented. The presence or absence of crimp can be determined by observing the fiber with an electron microscope. The degree of crimp of the crimped fibers can be, for example, 5 to 75, preferably 10 to 50, more preferably 15 to 50 per inch (2.54 cm) of length of one fiber. . Note that the degree of crimp is defined in JIS L1015.

  In addition, the hydrophilic fiber having crimps of the low-density skeleton layer has a larger compression work WC value than the pulp fiber used for the absorbent core, so that it is easily compressed and deformed. By pressing both sides in the width direction, the central portion is deformed and becomes familiar with the body, so that a body-fitted structure can be formed according to individual wearers (not uniform). Therefore, it feels soft and uncomfortable during wearing, and it is fit, so it is effective in preventing leakage. Furthermore, since the low density skeleton layer can maintain the skeleton structure even after absorbing the body fluid, it has good compression recovery and is difficult to twist. Therefore, the crotch width does not remain narrow and the absorption area can be maintained, which is also effective in preventing leakage.

  As the structure of the fiber having crimps, a nonwoven fabric, a web, and the like can be suitably used in addition to the continuous towed continuous fiber (filament). However, the towed continuous filament of tow can be excellent in both bulkiness (many gaps, low density) and strength, compressibility, and elasticity, and as a fiber constituting the low-density skeleton layer Particularly preferred.

(Continuous filament of opened tow)
The continuous filament of the opened tow refers to a state in which the continuous filament constituting the tow (fiber bundle) is opened. Examples of continuous filaments of opened tow include polysaccharides or derivatives thereof (cellulose, cellulose ester, chitin, chitosan, etc.), synthetic polymers (polyethylene, polypropylene, polyamide, polyester, polylactamamide, polyvinyl acetate, etc.) Among them, cellulose esters and cellulose are particularly preferable.

  The fineness of the opened tow continuous filament can be, for example, 1 to 16 denier, preferably 1 to 10 denier, and more preferably about 2 to 8 denier. The crimping degree of the continuous filament of tow can be, for example, 5 to 75, preferably 10 to 50, more preferably 15 to 50 per inch (2.54 cm). Further, a crimped fiber that is uniformly crimped is often used. The cross-sectional shape of the tow constituting fiber is not particularly limited, and may be any one of, for example, a circular shape, an oval shape, an irregular shape (for example, a Y shape, an X shape, an I shape, an R shape) or a hollow shape. Also good. The tow continuous filament is used in the form of a tow (fiber bundle) formed by bundling, for example, about 3,000 to 1,000,000, preferably 10,000 to 100,000 single fibers. be able to.

  The continuous filament of tow that has been opened can be obtained by opening the tow as a raw material by a known method, and if necessary, it is opened in a strip shape so as to have a desired size and bulk. be able to. The opening width of the tow is arbitrary, and can be, for example, about 100 to 2000 mm, preferably about 150 to 1500 mm. Opening the tow is preferable because the absorbent material (superabsorbent polymer) can be moved more easily. Moreover, the porosity of the shock absorber layer can be adjusted by adjusting the degree of tow opening.

  When the opened tow continuous filaments are arranged so as to be aligned in the longitudinal direction of the low-density skeleton layer 411, the liquid that has permeated through the low-density skeleton layer 411 moves in the longitudinal direction along the continuous tow filaments. Is promoted, and it is possible to draw the liquid from the wider area of the low-density skeleton layer 411 to the both-side absorbent core layer 413. This is preferable because the liquid drainage in the longitudinal direction of the incontinence pad is improved.

(Nonwoven fabric and web)
As the nonwoven fabric used as the hydrophilic fiber having crimps constituting the low-density skeleton layer, for example, a nonwoven fabric such as thermal bond or air-through is used. Examples of the material fibers constituting the nonwoven fabric include synthetic fibers such as polyethylene or polypropylene, synthetic fibers such as polyester and polyamide, recycled fibers such as rayon and cupra, and natural fibers such as cotton.

  A card web can also be used as the hydrophilic fiber having crimps constituting the low density skeleton layer.

(Water absorbing material)
In this embodiment, the low density skeleton layer further contains a water absorbing material in addition to the hydrophilic fibers having crimps. When the low-density skeleton layer is composed of hydrophilic fibers having crimps, the gap between the fibers is large, so that the liquid permeability is excellent. However, the hydrophilic fibers having crimps alone are not sufficient in holding the liquid. Furthermore, by containing a water-absorbing material, the liquid can be absorbed by the absorbent material while slowing the flow while receiving the liquid between the fibers of the low-density skeleton layer.

  As the water-absorbing material, known materials having a wide ability to absorb and retain liquid can be used, but a super absorbent polymer (SAP) is preferable. Various conventionally used polymers can be used as the superabsorbent polymer. For example, poly (sodium acrylate), (acrylic acid-vinyl alcohol) copolymer, cross-linked poly (sodium acrylate), (starch-acrylic acid) graft polymer, (isobutylene-maleic anhydride) copolymer and saponified product thereof, Examples include potassium polyacrylate and cesium polyacrylate. One of these absorptive polymers can be used alone or in admixture of two or more.

  In the low-density skeleton layer 411, the water-absorbing material is preferably supported by being entangled with the crimped hydrophilic fibers and not bonded by an adhesive. If the water absorbing material has a degree of freedom of movement, it can be reduced that the absorbing material absorbs water and expands and obstructs the flow of the liquid. A method for entanglement of a water-absorbing material with a hydrophilic fiber having crimps is known. For example, a water-absorbing material can be taken into the continuous filaments of the opened tow by air. FIG. 4 is an electron micrograph of the low-density skeleton layer produced in the example, and it is observed that the superabsorbent polymer (SAP) is supported without an adhesive between the continuous filaments of the opened tow. Is done.

(Density of low-density skeleton layer)
In this embodiment, the density (average value) of the low-density skeleton layer is smaller than the density (average value) of the both-side absorption core layer and the absorption core upper layer. Furthermore, the density of the low-density skeleton layer is preferably smaller than the density (average value) of the topsheet or the density of the cushion layer (average value) that may be disposed between the topsheet and the absorber. When the density of the low density skeleton layer is smaller than the density of the top sheet or the cushion layer, the liquid permeability of the low density skeleton layer can be improved.

  In the present specification, the measurement of the density (average value) of the members constituting the absorber (low density skeleton layer, both side absorption core layers and absorption core upper layers) is obtained by measuring the volume and mass of each layer. However, if the density of each layer is relatively uniform, a part of each layer may be cut out and the volume and mass thereof may be measured. In this specification, unless otherwise specified, the density, thickness and basis weight of the members constituting the absorber shall refer to the respective average values unless it is clear from the preceding and following contexts. And

  Moreover, in this specification, the calculation method of the density (average value) of the member which comprises an absorber shall be as follows. For the target member, the thickness is calculated according to the thickness measurement method described below, and at least five samples having a size of 20 mm × 20 mm or more are prepared in plan view at five different sites that are pressurized. The volume is calculated for each part. Subsequently, the mass of each sample is measured, divided by its volume, and the average value of at least five calculated values is taken as the density (average value) of the member.

In the present invention, when comparing the density and thickness of the members constituting the absorber, it is primarily a comparison of density and thickness at a low pressure (49 N / m ² ). In the comparison of density and thickness at (4900 N / m ² ), it is preferable that the predetermined relationship is satisfied. In addition, instead of the thickness at a low pressure (49 N / m ² ), it is possible to determine the size of the absorber by measuring or observing the cross section of the absorber.

Density of the low density skeleton layer is in the low pressure measurement pressure 49N / m ^2, preferably 0.01~0.125g / cm ^3, more preferably 0.015~0.063g / cm ^3, more preferably 0 0.023 to 0.050 g / cm ³ . Further, at a high pressure of 4900 N / m ² , the pressure is preferably 0.020 to 0.120 g / cm ³ , more preferably 0.030 to 0.100 g / cm ³ , and still more preferably 0.040 to 0.080 g. / Cm ³ .

(Thickness of low density skeleton layer)
In this embodiment, the thickness (average value) of the low-density skeleton layer is larger than the thickness (average value) of the both side absorbent core layers. Since the low-density skeleton layer is thicker than the absorbent core layers on both sides, the absorbent article has a medium-high structure and good cushioning, so it not only has a good fit but also fits the excretory part. It is possible to prevent the liquid from leaking through the gap. The thickness of the low density skeleton layer is preferably larger than the thickness of the upper layer of the absorbent core. When the thickness of the upper layer of the absorbent core is larger than the thickness of the low density skeleton layer, the liquid permeability and temporary storage properties of the low density skeleton layer may be impaired. However, the low-density skeleton layer tends to have a shape in which the thickness of the low-density skeleton layer is smaller in the vicinity of the end than the center in the width direction in a cross section obtained by cutting the absorber in the width direction. At this time, the thickness of the absorbent core upper layer on the low density skeleton layer is larger in the vicinity of the width direction end than the thickness in the width direction center of the low density skeleton layer, and the top surface of the absorbent core upper layer and the top of the both side absorbent core layers. The surface tends to be continuous. Therefore, the thickness (average value) of the absorbent core upper layer is smaller than the thickness (average value) of the low-density skeleton layer, but locally the thickness of the absorbent core upper layer is larger than the thickness of the low-density skeleton layer. Permissible.

  In the present specification, the method for measuring the thickness of the member constituting the absorber is as follows. Since it is difficult to collect a sample with a certain size, a plurality of samples are cut out from a portion that does not include the compressed groove (hinge) portion, but preferably a size of 20 mm × 20 mm or more.

Using a KES handy compression tester (Kato Tech Co., Ltd., KES-G5) under standard conditions (temperature 23 ± 2 ° C., relative humidity 50 ± 5%), measurement area 2.0 cm ² , measurement pressure 49 N / m ² Under the conditions of (0.5 gf / cm ² ) (low pressure) and 4900 N / m ² (50 gf / cm ² ) (high pressure), pressurize five or more different parts of the member and measure the thickness at each part. And let the average value of five or more measured values in each of the low pressure and the high pressure be the thickness of the member.

In the absorbent body 4 of the present embodiment, the thickness of the low density skeleton layer 411 is preferably 120% or more of the thickness of the both side absorption core layers 413 at a low pressure of 49 N / m ² , 140% or more, It can be 160% or more, and it is preferably 110% or more of the thickness of the low-density skeleton layer 411 at a high pressure of 4900 N / m ² , 115% or more, and further 120% or more. Moreover, in the absorber 4 of this embodiment, although the thickness of the low density frame | skeleton layer 411 is not limited, It can be 4.00-18.00mm in low pressure 49N / m < ² >, 10.00-15. It is preferably 0.000 mm. Moreover, in high pressure 4900N / m < ² >, it can be 3.80-8.00mm, and it is preferable that it is 4.20-6.50mm.

The thickness of the low density skeleton layer 411 is measured by a measuring method at low pressure 49N / m ² and a high pressure 4900 N / m ² as described above, if the object to know the relative thickness of each part, the simple The thickness of the layer in the cross section obtained by cutting the absorber can be measured and measured with a ruler.

(Basis weight of low density skeleton layer)
Range of the basis weight of the low density skeletal layer (average value) is preferably 200-500 g / m ^2, more preferably from 300~450g / m ^2.
Range of the basis weight of the hydrophilic fibers having a crimp in the low-density skeletal layer (average value) is preferably 90~400g / m ^2, more preferably from 150 to 350 g / m ^2. In order to form voids in the low-density skeleton layer and impart liquid permeability and cushioning properties, it is desirable that the basis weight of the hydrophilic fiber having crimps is larger than a predetermined amount, and more preferably larger. If it is too large, it may be too bulky and may deteriorate the wearability. The basis weight of the water-absorbing material in the low-density skeleton layer is calculated by measuring the dimensions of the low-density skeleton layer, carefully removing only the water-absorbing material from the low-density skeleton layer, and measuring the mass of the hydrophilic fibers. Can be obtained.

The range of the basis weight (average value) of the water-absorbing material in the low-density skeleton layer is preferably 20 to 70%, more preferably 30 to 60% with respect to the total basis weight of the hydrophilic fibers having crimps and the water-absorbing material. preferable. Moreover, it is preferable that the range of the basic weight (average value) of a water absorbing material is 50-400 g / m < ² >, More preferably, it is 100-300 g / m < ² >. If the basis weight of the water-absorbing material is small, water absorption may be insufficient. If the basis weight of the water-absorbing material is too large with respect to the hydrophilic fibers having crimps, the low-density skeleton layer may retain a large amount of liquid, and the liquid permeation performance may be reduced. There is a fear. The measurement of the basis weight of the water-absorbing material in the low-density skeleton layer is to measure the size of the low-density skeleton layer, carefully take out only the water-absorbing material from the low-density skeleton layer, and measure the mass of the extracted water-absorbing material, It can be calculated.

(Center absorption core upper layer)
In the absorbent body 4 of the present embodiment, the absorbent core upper layer 412 extends in the longitudinal direction at the center portion 4C in the width direction, contacts the low density skeleton layer 411 on the upper side of the low density skeleton layer 411, and is on the surface sheet 2 side. Exists. The absorbent core upper layer 412 is a member that is laminated with the low-density skeleton layer 411 and covers the low-density skeleton layer 411, and basically has the same shape as the low-density skeleton layer 411 in plan view (plan view). However, as long as the absorbent core upper layer 412 covers the low-density skeleton layer 411, it may have a shape further extended in the longitudinal direction of the low-density skeleton layer 411. The absorbent core upper layer 412 may be shorter in the length direction than the low-density skeleton layer 411 as long as the low-density skeleton layer 411 covers a region that can function as a liquid-permeable layer and a temporary storage layer. On both sides in the width direction of the absorbent core upper layer 412 and the low density skeleton layer 411, both side absorbent core layers 413 exist on both sides in contact with both the absorbent core upper layer 412 and the low density skeleton layer 411. The absorbent core upper layer 412 preferably forms an absorbent core layer that is continuous with both side absorbent core layers 413 in the width direction. The absorbent core upper layer 412 may be formed separately from the both side absorbent core layers 413, or the absorbent core upper layer 412 may be integrally formed simultaneously with the both side absorbent core layers 413.

  In the absorbent body 4 and the absorbent core 41 of the present embodiment, the low-density skeleton layer 411 has a density (average value) smaller than the density (average value) of the absorbent core upper layer 412, and the absorbent core upper layer 412 has both side absorbent core layers. The absorbent core upper layer 412 has a thickness (average value) smaller than the thickness (average value) of both side absorbent core layers 413, and has a density (average value) smaller than the density (average value) of 413. The low-density skeleton layer 411 is likely to have a shape in which the thickness of the low-density skeleton layer is smaller in the vicinity of the end than the center in the width direction in a cross section obtained by cutting the absorber in the width direction. At this time, the absorption core upper layer formed on the low-density skeleton layer is thicker in the vicinity of both ends than the thickness near the center in the width direction of the absorption core upper layer, and the top surface and both side absorption cores of the absorption core upper layer The shape tends to be continuous with the top surface of the layer (such a continuous shape is preferred). Therefore, the thickness (average value) of the absorbent core upper layer is smaller than the thickness (average value) of the low-density skeleton layer, but locally the thickness of the absorbent core upper layer is larger than the thickness of the low-density skeleton layer. Permissible.

  Constituent elements of the absorbent core upper layer 412 include, for example, hydrophilic fibers. More specifically, cellulose such as pulverized pulp and cotton; regenerated cellulose such as rayon and fibril rayon; semisynthetic cellulose such as acetate and triacetate A fibrous polymer; a thermoplastic hydrophobic chemical fiber; a hydrophobized thermoplastic hydrophobic chemical fiber; and any combination thereof. Moreover, you may use the granular material which consists of superabsorbent polymers, such as a sodium acrylate copolymer, for example as a component of an absorption core upper layer. However, the absorbent core upper layer 412 most preferably contains pulverized pulp and superabsorbent polymer (SAP) from the viewpoint of absorption performance.

  In this embodiment, the density (average value) of the absorbent core upper layer 412 is larger than the density (average value) of the low-density skeleton layer 411. By disposing the absorbent core upper layer 412 having a density higher than the density of the low density skeleton layer 411 and high water absorption performance on the surface sheet 2 side of the low density skeleton layer 411, rewetting and liquid leakage are reduced and prevented. It is.

Density of the absorbent core layer 412 (average value), the low pressure measurement pressure 49N / m ^2, preferably 0.030~0.120g / cm ^3, more preferably at 0.040~0.080g / cm ³ is there. Further, at a high pressure of 4900 / m ² , the pressure is preferably 0.016 to 0.400 g / cm ³ , more preferably 0.090 to 0.150 g / cm ³ , and still more preferably 0.100 to 0.120 g. / Cm ³ . The method for measuring the density of the absorbent core upper layer is the same as the method described above as the method for measuring the density of the low-density skeleton layer.

  In the absorbent body 4 of this embodiment, the thickness (average value) of the absorbent core upper layer 412 is preferably smaller than the thickness (average value) of the low-density skeleton layer 411. If the thickness of the absorbent core upper layer 412 is too large, the thickness of the low-density skeleton layer 411 decreases and the space between the fibers of the low-density skeleton layer 411 decreases, so that the liquid permeability and the liquid temporary storage performance deteriorate. . The thickness of the absorbent core upper layer 412 is preferably 40% or less of the thickness of the low-density skeleton layer 411, more preferably 30% or less, depending on the configuration (composition) of the low-density skeleton layer 411 and the absorbent core upper layer 412. A thickness of 25% or less or 20% or less may be preferable. The lower limit of the thickness of the absorbent core upper layer 412 is preferably 5% or more, more preferably 10% or more, of the thickness of the low-density skeleton layer 411. Furthermore, the thickness can be 15% or more.

  The measurement of the thickness of the low-density skeleton layer 411 and the absorbent core upper layer 412 is defined by the measurement method at the low pressure and the high pressure described above. The thickness of the absorption core upper layer is measured by separating the absorption core upper layer from the absorber, and the total thickness of the low-density skeleton layer and the absorption core upper layer of the absorber and the thickness of the low-density skeleton layer are obtained, and their thicknesses are determined. You may obtain | require as a difference. For the purpose of relative comparison of thicknesses, the relative thickness of each layer in a cross section obtained by cutting the absorber can be easily determined by visual observation, or the thickness of each layer can be measured and measured with a ruler.

In the absorbent body 4 of this embodiment, the thickness of the absorbent core upper layer 412 is not limited, but can be 0.50 to 5.00 mm at a low pressure of 49 N / m ² , and is 1.00 to 4.00 mm. Preferably there is. Moreover, in high pressure 4900N / m < ² >, it can be 0.50-3.00mm, and it is preferable that it is 0.600-2.00mm.

  The basis weight (average value) of the absorbent core upper layer 412 is preferably smaller than the basis weight (average value) of the low-density skeleton layer 411. If the basis weight of the absorbent core upper layer 412 is too large, the liquid permeation performance and temporary storage performance of the low density skeleton layer 411 may be impaired. The basis weight of the absorbent core upper layer 412 is more preferably smaller than the basis weight of the both side absorbent core layers 413. If the basis weight of the absorbent core upper layer 412 is less than the basis weight of the both-side absorbent core layer 413, it is preferable because the absorbent core upper layer 412 functions more fully to guide the liquid to the low density skeleton layer 411.

The basis weight (average value) of the absorbent core upper layer 412 is preferably 50 to 200 g / m ² , more preferably 80 to 150 g / m ² . The basis weight of absorbent fibers such as pulp is preferably ²⁰ to 150 g / m ² , more preferably 40 to 100 g / m ² . The basis weight of the absorbent material such as the superabsorbent polymer (SAP) is preferably 30 to 200%, more preferably 60 to 150%, where the basis weight of the absorbent fiber is 100%. The basis weight of the absorbent material such as superabsorbent polymer (SAP) is, 10 to 150 g / m ^2, more 20 to 100 g / m ^2, it is preferable that 30~70g / m ^2.

(Both side absorption core layer)
In the absorbent body 4 of this embodiment, the both side absorbent core layers 413 are adjacent to both (side surfaces) of the low-density skeleton layer 411 and the absorbent core upper layer 412 on both sides of the width direction central portion 4C in the longitudinal direction. It is preferable that it extends and extends at least in the length of the low-density skeleton layer 411. The both side absorbent core layers 413 must be in contact with the side walls of the low density skeleton layer 411 in order to draw out the liquid temporarily stored in the low density skeleton layer 411. Further, both side absorbent core layers 413 are present in contact with the side walls of the absorbent core upper layer 412 in order to prevent leakage of the liquid temporarily stored in the low density skeleton layer 411 to the surface sheet 2 side, or A layer continuous with the upper layer 412 is preferable.

  In the absorbent body 4 and the absorbent core 41 of this embodiment, the both side absorbent core layers 413 have a density (average value) larger than the density (average value) of the low density skeleton layer 411, and the thickness of the low density skeleton layer 411. It has a thickness (average value) smaller than (average value), preferably has a density larger than the density of the absorbent core upper layer 412, and has a thickness larger than the thickness of the absorbent core upper layer 412.

  In this embodiment, the density (average value) of the both side absorption core layers 413 is larger than the density (average value) of the low-density skeleton layer 411.

The density (average value) of both side absorption core layers is preferably 0.060 to 0.110 g / cm ³ , more preferably 0.065 to 0.100 g / cm ^{3 at} a low pressure of 49 N / m ^2. More preferably, it is 0.070-0.090 g / cm < ³ >. Further, at a high pressure of 4900 N / m ² , preferably 0.120 to 0.300 g / cm ³ , more preferably 0.130 to 0.250 g / cm ³ , and still more preferably 0.140 to 0.200 g. / Cm ³ .

In the absorbent body 4 of the present embodiment, the thickness (average value) of the both side absorption core layers 413 depends on the configuration (composition) of the both side absorption core layers 413 and is not limited, but at a low pressure of 49 N / m ² . , 2.00 to 10.00 mm, preferably 4.50 to 8.00 mm. Moreover, in high pressure 4900N / m < ² >, it can be 1.00-4.00mm, and it is preferable that it is 2.00-3.50mm. Moreover, it is preferable that the thickness (average value) of the both-sides absorption core layer 413 satisfy | fills the relationship of relative thickness with the thickness (average value) of an above-described absorption core upper layer.

The basis weight (average value) of the both-side absorbent core layer 413 is preferably 200 to 700 g / m ² , more preferably 250 to 500 g / m ² . The basis weight of absorbent fibers such as pulp is preferably 10 to 400 g / m ² , more preferably 200 to 300 g / m ² . The basis weight of the absorbent material such as the superabsorbent polymer (SAP) is preferably 30 to 200%, more preferably 60 to 150%, with the hydrophilic fiber basis weight being 100%. The basis weight of the absorbent material such as superabsorbent polymer (SAP) is, 50 to 400 g / m ^2, more 150 to 350 g / m ^2, it is preferable that 200-30Og / m ^2.

  The components of the side absorbent core layers can be similar to the components of the absorbent core upper layer. The both-side absorbent core layer is most preferably one containing ground pulp and superabsorbent polymer (SAP) in view of absorption performance.

  The basis weight (average value) of the both-side absorbent core layer 413 is preferably larger than the basis weight (average value) of the absorbent core upper layer 412 and larger than the basis weight (average value) of the low-density skeleton layer 411. If the basis weight of the absorbent core upper layer 412 is too large, the liquid permeation performance and temporary storage performance of the low density skeleton layer 411 may be impaired. The both side absorption core layer 413 is a part responsible for absorption and liquid retention of the absorber, and functions as a member that supports the fragile low-density skeleton layer 411 against body pressure in order to fulfill its functions. In order to achieve the above, it is desirable that the basis weight of both side absorbent core layers 413 is larger than the basis weight of the absorbent core upper layer 412, and further the low density skeleton layer 411.

(Core wrap)
The core wrap 42 of the absorbent body 4 of the present embodiment has a liquid permeability that allows fluids such as body fluids discharged from the human body to permeate, and has a barrier property that does not allow the contained components of the absorbent core to permeate. Although it will not be restrict | limited if it has, For example, sheet-like fiber structures, such as a woven fabric, a nonwoven fabric, and a tissue, are mentioned. Examples of the constituent material include natural fibers and chemical fibers.

Each range of the absorbent core described above (low density skeleton layer, absorbent core upper layer, both side absorbent core layer) and the composition, density, thickness, basis weight and other preferred ranges of the components, and the relationship of relative amounts are all It is clear that it is possible to combine them, and it is more preferable that each is in a preferable range. For example, the density of 0.023~0.050g / cm ³ low-density skeletal layer with a low pressure 49N / m ^2, 10.00~15.00mm thickness at low pressure ^{49N / m 2, 300~450g / m} 2 The absorption core upper layer has a low pressure of 49 N / m ² and a density of 0.040 to 0.080 g / cm ³ , a thickness of 5 to 30% of the thickness of the low density skeleton layer 411, and 80 to 150 g / m. ^{2 having} a basis weight of ² and a density of 0.070 to 0.090 g / cm ³ at a low pressure of 49 N / m ² and a thickness of 4.50 to 8.00 mm at a low pressure of 49 N / m ² . A basis weight of 250 to 500 g / m ² is preferred.

(Manufacturing method of absorber)
Manufacture of the absorber of this embodiment can follow a conventionally well-known manufacturing method of an absorber. In particular, a method for producing a crimped hydrophilic fiber, a method for supporting an absorbent on a crimped hydrophilic fiber, and a method for producing an absorbent core layer comprising a piled fiber in which an absorbent is dispersed in pulp fibers are known. It has been. In order to manufacture the absorbent body of the present embodiment, for example, the material of the low-density skeleton layer in which the absorbent material is supported on the crimped hydrophilic fiber after the core wrap lower layer is laid on the belt conveyor in the width direction. A low density skeletal layer is formed by supplying to the central part, and a piled body in which an absorbent is dispersed in pulp fibers is supplied to both sides in the width direction of the material of the low density skeleton layer to form both side absorbent core layers. At the same time, an absorbent core upper layer is formed by further supplying a fiber stack in which an absorbent is dispersed in pulp fibers on a low-density skeleton layer formed on a belt conveyor. After further laminating the core wrap upper layer on the formed absorbent core layer on both sides and the upper layer of the absorbent core, the core wrap lower layer and the core wrap upper layer are joined and cut into the shape of each absorber to obtain the absorber. Can do.

  In one embodiment of the present invention, the incontinence pad 1 can include a second sheet as a cushioning material 8 (see FIG. 6) between the liquid-permeable top sheet 2 and the absorbent body 4. As the second sheet, the same sheet as the liquid-permeable surface sheet can be used.

  In one embodiment of the present invention, the incontinence pad 1 includes a side sheet 5 and an elastic body 6 for forming a three-dimensional gather 7 on the skin contact surface side of the liquid-permeable surface sheet 2 (see FIGS. 1 and 6). ) Can be included. The structures of the side sheet 5 and the elastic body 6 for forming such a three-dimensional gather 7 are known.

(Pressed groove)
FIG. 5 is a plan view showing the incontinence pad which is made flat by removing the elastic body in the three-dimensional gather from the incontinence pad schematically shown in FIG. In the incontinence pad 1 of the present embodiment, the compression grooves (hinges) 9 extending from the topsheet 2 to the absorbent core layers on both sides of the absorber 4 are extended in the longitudinal direction on both sides in the width direction of the absorber 4. Can be formed. Such a compressed groove 9 is also called a hinge, and swells the central portion in the width direction of the absorbent body 4 and retains the shape of the absorbent body 4 even when body pressure in the width direction is applied to the incontinence pad 1 between the crotch. Acts as follows. The pressing groove (hinge) 9 can be formed by embossing, for example. Since the compressed groove (hinge) 9 is difficult to hydrogen bond when stepped on the low-density skeleton layer, the hinge is easy to come off, and the cushioning property is also expressed, so that it is formed only on the both side absorption core layers. preferable. However, a part of the low density skeleton layer may be included as long as the function of the low density skeleton layer is maintained.

  In addition to the pressing grooves (hinges) 9 extending in the longitudinal direction on both sides in the width direction shown in FIG. 5, the striped pressing grooves extending in the width direction on both ends in the longitudinal direction of the intermediate portion in the longitudinal direction (Hinge) can be provided (not shown). This squeezing groove (hinge) has the effect of suppressing the movement of hydrophilic fibers, particularly tow, constituting the low-density skeleton layer, and facilitating the formation of a body fit structure. Moreover, since the liquid spread to the side part of a tow | toe is suppressed, a liquid becomes easy to flow along a tow | toe.

(Incontinence pad manufacturing method)
After manufacturing the absorber as described in the embodiment of the present invention, the incontinence pad can be manufactured by a known method. An incontinence pad is manufactured by laminating and forming a front sheet, a back sheet, a cushion material, a side sheet (three-dimensional gather), and the like.

  In FIG. 6, the structural member of the incontinence pad 1 of embodiment of this invention is shown as a model end view in the VI-VI end surface of FIG. In FIG. 6, 1 is an incontinence pad, 2 is a surface sheet, 3 is a back sheet, 4 is an absorber, 41 is an absorbent core, 42 is a core wrap, 5 is a side sheet, 6 is an elastic body, 7 is a three-dimensional gather, It is a cushioning material. In FIG. 6, the pressing groove is omitted.

(Another embodiment of an absorbent article)
An incontinence pad according to a second embodiment of the present invention will be described. This incontinence pad is the incontinence of the first embodiment described with reference to FIGS. 1 to 6 in that the low-density skeleton layer is widened and reduced in basis weight at both longitudinal end portions compared to the longitudinal intermediate portion. Different from the pad.

  FIG. 7 is a schematic plan view of the absorbent body 4 of the incontinence pad 1 of the second embodiment, FIG. 8 is a schematic end view of the absorbent core 41 in the longitudinal direction, and FIG. 9 is the incontinence pad 1 of the second embodiment. FIG. The incontinence pad 1 has a longitudinal direction L and a width direction W perpendicular to the longitudinal direction in a plan view. Also in FIGS. 8-10, the corresponding members of the first embodiment are indicated using the same reference numerals as in FIGS. However, in the schematic plan view of the absorber 4 in FIG. 7, the broken line indicates the shape of the low-density skeleton layer 411.

  Referring to FIG. 7, the absorber 4 is partitioned into an intermediate portion 4M and longitudinal end portions 4E on both sides of the longitudinal intermediate portion 4M at the center in the longitudinal direction. The longitudinal intermediate portion 4M includes a position corresponding to the excretion opening, and the longitudinal end portions 4E correspond to the abdomen and buttocks of the body. The absorbent core 41 has the same configuration as the incontinence pad of the first embodiment in the longitudinal intermediate portion 4M. That is, it is composed of the low-density skeleton layer 411, the central absorbent core upper layer 412, and both-side absorbent core layers 413 shown in FIG.

  In the second embodiment, the longitudinal intermediate portion 4M and the longitudinal both ends 4E in the absorbent body 4 are a portion corresponding to the excretion opening and a portion corresponding to the abdomen and buttocks of the body, respectively. It may be the position and dimensions described above in the description of the first embodiment. That is, the longitudinal intermediate portion 4M includes a portion corresponding to the excretion port position in the longitudinal direction, and is a region having a dimension of about 50 mm to 200 mm, preferably about 80 to 180 mm. The longitudinal intermediate portion 4M may be unevenly distributed on either the front or rear side of the absorber. Further, it is not necessary that the longitudinal dimensions of the longitudinal both ends 4E are the same. Each longitudinal dimension of the longitudinal both ends 4E may be 10 mm or more, and may be a remaining dimension that appropriately defines the position and dimension of the longitudinal intermediate part 4M from the entire length of the absorber.

  In the second embodiment, as shown in the plan view of FIG. 7, in the absorbent core 41, the low-density skeleton layer 411 is centered in the width direction at the longitudinal end portions 4 </ b> E (only one of the longitudinal end portions 4 </ b> E). The total basis weight or thickness of the low-density skeleton layer 411 that extends not only to the width portion but also to both sides in the width direction and extends to the width direction center portion and the width direction both side portions at both longitudinal ends 4E. The basis weight or thickness of the low-density skeleton layer 411 in the intermediate portion 4M in the longitudinal direction is made smaller. Referring to FIG. 7, the width of the low-density skeleton layer 411 is gradually widened at both ends 4E in the longitudinal direction from the middle portion in the longitudinal direction toward both ends of the absorbent core.

  Here, as in the case of the first embodiment, both side absorbent core layers 413 are also formed in both longitudinal ends 4E at both longitudinal ends 4E at both longitudinal ends 4E. This is an extended form (the region indicated by reference numeral 4S in FIG. 2, but the shape of the both-side absorbent core layer 413 is not shown in FIG. 7). And the low density frame | skeleton layer 411 exists in the longitudinal direction both ends 4E, and the part expanded from the width direction center part 4C has overlapped with the both-sides absorption core layer 413 on the non-skin surface side of the both-sides absorption core layer 413.

  FIGS. 8A and 8B are schematic end views of the longitudinal end portions 4E of the absorbent core 41. FIG. Referring to FIG. 8 (a), FIG. 8 (b) is an end view or a side view showing the end of the absorbent core 41, but the low-density skeleton layer 411 is widened from the central portion 4C in the width direction to absorb both side portions. The non-skin surface side of the core layer 413 extends so as to be in contact with both side absorption core layers 413. The absorbent core upper layer 412 and both side absorbent core layers 413 are on the skin surface side of the low density skeleton layer 411 and form a continuous absorbent core layer. The basis weight or thickness of the widened low-density skeleton layer 411 at both longitudinal ends 4E is smaller than the basis weight or thickness at the longitudinal intermediate portion 4M.

  In the absorbent article of the present invention, the low-density skeleton layer 411 has a large thickness (bulky). According to the absorbent article of the second embodiment as described above, the low-density skeleton layer 411 is widened at both ends in the longitudinal direction and the basis weight is reduced or the thickness is reduced. The discomfort on the ventral side and the buttocks side is reduced. Further, as will be described later, both ends in the longitudinal direction of the absorber can be reduced in thickness by embossing or the like, but the low density skeleton layer 411 is widened to reduce the basis weight, so that the thickness is reduced. The thickness return after processing such as embossing is reduced, and the discomfort is further reduced. Since a structure having a large thickness (bulk height) in the middle portion in the longitudinal direction near the excretion opening and a low basis weight or thin thickness in the longitudinal direction both ends on the abdomen and buttocks side is provided, the absorbent article is Fits the body without creating a gap in between. A feeling of discomfort is reduced and liquid leakage on the surface can be suppressed, and liquid leakage can be reduced.

  Further, the low density skeleton layer 411 is widened at both ends in the longitudinal direction, and the hydrophilic fibers of the low density skeleton layer 411 are overlapped with the absorbent material made of pulp / SAP of both side absorbent core layers 413, and the absorbent material Since they are entangled, the shape of the absorber at both ends is suppressed. Further, the both side absorbent core layers 413 made of pulp / SAP are hardened when embossed (compressed), but when the widened portion of the low-density skeleton layer 411 is superimposed on the both side absorbent core layers 413, There is also an effect that the hardness of the part becomes soft. Furthermore, since the hydrophilic fibers constituting the low-density skeleton layer 411 extend so as to overlap the both-side absorbent core layers 413 at both ends in the longitudinal direction, the absorber area is effectively utilized and effective in preventing leakage.

  When the low-density skeleton layer 411 is composed of continuous fibers of the opened tow, the continuous fibers of the opened tow are simply widened at both ends in the longitudinal direction. Since the width is widened, the basis weight is reduced, and the thickness is also reduced, it is possible to easily realize the desired conditions as the second embodiment, and there is an advantage that manufacture is easy. In addition, when the low-density skeleton layer 411 is made of continuous tow fibers that have been spread, if the width is increased at both ends in the longitudinal direction, the basis weight of the continuous fibers at the ends decreases, so that cutting at the ends is easy. There is also an advantage that continuous production becomes easy.

  In the second embodiment, when the low-density skeleton layer 411 is widened at both ends 4E in the longitudinal direction and extends so as to overlap the non-skin surface side of both side absorbent core layers 413, the absorbent core upper layer 412 is in the middle in the longitudinal direction. In the region where the low-density skeleton layer 411 overlaps the non-skin surface side of the both-side absorbent core layer 413 at the time of manufacture, the absorbent core upper layer 412 is separated from the absorbent core upper layer 412. And a space may be formed between the low-density skeleton layer 411. FIG. 8B shows a space formed between the absorbent core upper layer 412 and the low-density skeleton layer 411 when the low-density skeleton layer 411 is widened and overlaps the non-skin surface side of both side absorbent core layers 413. It is an end elevation which shows notionally the section of the form which left 4V as a space without being filled with absorbents, such as pulp. FIG. 8B shows an end face when the absorbent core 41 is cross-sectioned in the middle of the end portion in the longitudinal direction. Therefore, the width of the low-density skeleton layer 411 is in the middle of widening, and It has not been widened. Such a space 4V is easy to be formed particularly in the transition region from the middle portion in the longitudinal direction to both end portions in the longitudinal direction.

  On the other hand, FIG. 8A is formed between the absorbent core upper layer 412 and the low-density skeleton layer 411 when the low-density skeleton layer 411 is widened and overlaps the non-skin surface side of the both-side absorbent core layer 413. FIG. 4 is a view showing a form in which the space 4V is formed by being filled with an absorbent material such as pulp of the absorbent core upper layer 412; In the manufacture of the absorbent core in the second embodiment, after forming the low-density skeleton layer with the width at both longitudinal ends widened, it is stacked with the absorbent core upper layer and both side absorbent core layers. The space 4V may disappear naturally, or when the space 4V is about to be formed, the space 4V may be intentionally filled by filling the space 4V with the absorbent core material. In the second embodiment, all and a part of the end portions in the longitudinal direction may be in any form of FIG. 8 (a) and FIG. 8 (b).

  In the second embodiment, the low-density skeleton layer 411 may be a low-density skeleton layer containing a crimped hydrophilic fiber and a water-absorbing material, but the low-density skeleton layer 411 is a continuous fiber of opened tow. Preferably it consists of. When the low-density skeleton layer 411 is made of continuous fibers of opened tow, widening the tow results in a decrease in basis weight and a decrease in thickness. That is, the low-density skeleton layer 411 is widened at both ends 4E in the longitudinal direction, the width in the width direction W is increased, the basis weight in the direction perpendicular to the longitudinal direction L and the width direction W is reduced, and the thickness is also reduced.

  In the second embodiment, when the low density skeleton layer 411 is widened at both ends 4E, the longitudinal intermediate portion 4M is formed so that the low density skeleton layer 411 has a uniform thickness at the tips of both ends 4E after being widened. Although it is preferable that the width is gradually and uniformly widened from the end of the longitudinal end portion 4E, the method of widening is not necessarily uniform.

  For example, in the width direction of both ends in the longitudinal direction, the basis weight of either the center or the outside may be large or small, and in an extreme example, the low-density skeleton layer 411 is divided into two branches and widened. The low density skeleton layer 411 may not exist near the center in the width direction. Further, in the width direction at both ends in the longitudinal direction, the width of the low-density skeleton layer 411 does not uniformly increase from the intermediate portion in the longitudinal direction toward the tip, but suddenly increases in the vicinity of the end point of the intermediate portion in the longitudinal direction. The width may be toward the tip at the width, or may be further widened thereafter.

  The material, composition, shape, dimension, density, basis weight and other configurations of the central absorbent core upper layer and both side absorbent core layers in the second embodiment are such that the low density skeleton layer is widened at both longitudinal ends, and the basis weight. Alternatively, as the thickness decreases, the configurations of the central absorbent core upper layer and both side absorbent core layers may be changed as appropriate, but basically may be within the range described for the first embodiment.

  The low-density skeleton layer in the second embodiment is widened at both ends in the longitudinal direction as compared with the intermediate portion in the longitudinal direction and has a reduced basis weight or thickness. The material, composition, and density of the low-density skeleton layer at both ends in the longitudinal direction may be the same as described above for the intermediate portion in the longitudinal direction and both ends in the longitudinal direction.

The basis weight (average value) of the low-density skeleton layer at both ends in the longitudinal direction is not limited, but it is preferably 30 to 400 g / m ² , more preferably 50 to 50% because it decreases compared to the intermediate portion in the longitudinal direction. 350 g / m ² . The method for measuring the basis weight (average value) of the low-density skeleton layer may be the same as in the first embodiment.

The thickness (average value) of the low-density skeleton layer at both ends in the longitudinal direction is not limited, but can be 1.00 to 18.00 mm at a low pressure of 49 N / m ² , and is 1.50 to 15.00 mm. Preferably there is. Moreover, in high pressure 4900N / m < ² >, it can be 0.70-8.00mm, and it is preferable that it is 1.00-6.50mm. The method for measuring the thickness (average value) of the low-density skeleton layer may be the same as in the first embodiment.

  The density (average value) of the low-density skeleton layer at both ends in the longitudinal direction may be the same as in the first embodiment, but the density may decrease when the low-density skeleton layer is widened. The method for measuring the density (average value) of the low-density skeleton layer may be the same as in the first embodiment.

  The manufacture of the absorbent body in the second embodiment may be the same as that in the first embodiment, except that the low-density skeleton layer is widened and the basis weight is reduced in at least one of the longitudinal ends. The method of widening and reducing the basis weight at both ends in the longitudinal direction of the low-density skeleton layer reduces the basis weight as a result of widening the tow in the case of a continuous fiber of opened tow. Therefore, for example, a material of a low-density skeleton layer in which a absorbent core is supported on a member in which a hydrophilic fiber having crimps is widened on a belt conveyor on which a core wrap lower layer is laid is supplied to the center in the width direction. A low-density skeleton layer is formed, and a piled body in which absorbent material is dispersed in pulp fibers is supplied to both sides in the width direction of the material of the low-density skeleton layer to form both side absorbent core layers, and on the belt conveyor. An absorbent core upper layer is formed by further supplying a piled body in which an absorbent is dispersed in pulp fibers on the low-density skeleton layer to be formed. After further laminating the core wrap upper layer on the formed absorbent core layer on both sides and the upper layer of the absorbent core, the core wrap lower layer and the core wrap upper layer are joined and cut into the shape of each absorber to obtain the absorber. Can do.

  FIG. 9 is a plan view of the absorber in the second embodiment. In FIG. 9, for example, a region 10 indicated by a mesh, which is obtained by widening the low-density skeleton layers at both ends in the longitudinal direction of the absorber, is embossed, for example, so that the thickness is reduced. Since the thickness of the absorber in the region 10 can be reduced by this embossing, the wearing feeling is enhanced. Also, in this embossing, if the basis weight of the tow is large, hydrogen bonding is difficult, so the embossing is not effectively applied and the tows are easily detached, but in the second embodiment, the basis weight of the tow is small, Embossing is easy and the thickness of the absorber can be reduced. It is preferable to make this embossing (squeezing) pattern fine, and for example, a square shape, a lattice shape, a dot shape, a streaky shape, a broken shape, or the like can be used. Further, the entire area 10 may be pressed with a flat plate.

  In addition, the embossing and press which make thickness small in the longitudinal direction both ends or the vicinity of this absorber are not limited to a 2nd embodiment, It can employ | adopt preferably also in a 1st embodiment.

(Other uses)
Although the incontinence pad has been described as a preferred embodiment of the absorbent article of the present invention, the absorbent article of the present invention is not limited to this, and is particularly limited as long as it is an article for absorbing excreta discharged from the human body. However, it is applicable to sanitary napkins and disposable diapers, for example.

  The absorbent article of the present invention will be described with reference to the following examples, but it is obvious that the absorbent article of the present invention is not limited to these examples.

Although the incontinence pad described with reference to FIGS. 1 to 6 was manufactured as an example, a rectangular absorber was manufactured instead of an hourglass type. In the following examples and comparative examples, a layer formed at a position corresponding to the low-density skeleton layer in the end view of FIG. 3 is a “center lower layer”, and a layer formed at a position corresponding to the absorbent core upper layer is a “center upper layer”. A layer formed at a position corresponding to both side absorption core layers is referred to as a “side part”. Note that gsm represents g / m ² .

The following materials were used in Examples and Comparative Examples.
-Pulp fiber: SuperSoft (International Paper)
・ Superabsorbent polymer (SAP): SA60S (Sumitomo Seika Co., Ltd.)
・ Tow: Acetate tow (Daicel Corporation)
・ Core wrap: Tissue 14gsm
・ Surface sheet: Air-through non-woven fabric 22gsm
・ Second sheet: Air-through non-woven fabric 25gsm
・ Back sheet: film

  In the above, pulp fibers and tow used were mixed with superabsorbent polymer (SAP). The tow used was a process in which the tow having crimps was opened and then air was blown to entangle the SAP and the tow. The state in which SAP is dispersed and held in the continuous filament of the opened tow obtained after this treatment is shown in the electron micrograph of FIG. In the electron micrograph of FIG. 4, it is recognized that continuous tow filaments are entangled and crimped, and SAP spherical particles are entangled and held between the fibers.

In the examples, the incontinence pad was 257 mm long × 85 mm wide in the dimensions of the absorbent core. The width of the “center lower layer” and the “center upper layer” were both 30 mm, and the width of the “side portion” was 27.5 mm. The middle lower layer was formed by the opened tow / SAP, the middle upper layer was formed by the pulp fiber / SAP, and both sides were formed by the pulp fiber / SAP. Tables 1 and 2 show the configuration (composition) of each layer. The absorbent core having the above structure was covered with a core wrap to form an absorbent body.
In Tables 1 and 2, the composition of each layer of the central upper layer, the central lower layer and the side part is the basis weight indicated by the basis weights of “pulp” (pulp fiber), “SAP” and “tow”, respectively. did. For example, in Example 1, the central upper layer contains pulp fiber in an amount of 60 g / m ² and SAP in an amount of 30 g / m ² , and the central lower layer has an amount of SAP of 114 g / m ² and tow of 180 g / m ^2. is intended to include an amount of m ^2, side included the pulp fiber quantity and SAP 208g / m ² in an amount of 253 g / m ^2.

  The obtained absorbent body is laminated in the order of the back sheet, the absorbent body, the cushioning material, the top sheet, and the three-dimensional gather, and after joining at a predetermined position, the compressed groove (hinge) from the top sheet to the absorbent body is shown in FIG. The incontinence pad was produced in the shape shown in FIG.

(Examples 1-4)
As described above, incontinence pads of Examples 1 to 4 were produced with the composition of each layer shown in Tables 1 and 2. However, although the pressing groove was not formed in Examples 1-3, the pressing groove was formed in Example 4.

(Comparative Example 1)
Similar to Example 1, but without using tow in the absorbent core, using only pulp fibers and SAP, and containing the same amount of SAP as Example 1 and the amount of pulp fibers corresponding to the amount of SAP. An incontinence pad was prepared.

(Comparative Example 2)
Similar to the embodiment, except that the incontinence pad composed only of the tow / SAP layer of the central lower layer and the pulp / SAP layers of both sides is formed without forming the upper central layer on the lower central layer. Produced. The composition of each layer was as shown in Table 2.

(Comparative Example 3)
As in the example, an incontinence pad having an absorbent core in which only an absorbent core layer made of pulp / SAP having a width of 85 mm was laminated as an upper layer on a central lower layer (30 mm width) made of tow / SAP was prepared. In this incontinence pad, the central lower layer (low density skeleton layer) is in contact with the upper absorbent core layer in the upper direction, but there is no absorbent core layer in the width direction. The composition of each layer was as shown in Table 2.

(Evaluation)
For the incontinence pads of Examples and Comparative Examples, the density, thickness, and absorbability (absorption time, rewetting, diffusion length) were measured by the measurement method defined above and the evaluation method described below, and the 45 ° mole was measured. Tested.

(Measurement method of absorbency under load)
Absorption performance was evaluated with a pressure of 5400 N / m ² (55 gf / cm ² ) applied to the incontinence pad.
i) An acrylic plate with a cylinder (inner diameter 30 mmφ) was placed on the incontinence pad that was spread horizontally, and a weight was placed on the acrylic plate.
ii) 40 ml of artificial urine was dropped in 4 seconds into a cylinder located in the center in the length direction and width direction of the incontinence pad, and the time from the start of dropping until the liquid disappeared was measured (absorption time). The composition (% by weight) of the artificial urine was urea 2%, sodium chloride 0.9%, magnesium sulfate heptahydrate 0.08%, calcium chloride dihydrate 0.03%, ion-exchanged water 97.09%,
iii) After 5 minutes, 40 ml of artificial urine was further added dropwise, and the absorption time and diffusion length were measured in the same manner as the first time.
iv) Ten minutes after the first dropping, the weight and the acrylic plate were removed, and a weighed qualitative filter paper (Advantech, No2, 10 cm square, about 50 g) and a 3.5 kg (10 cm square) weight were placed on the dropping position.
v) 13 minutes after the first dripping, the weight and filter paper were removed, and the amount of rewet was calculated from the amount of liquid absorbed by the filter paper.

(45 ° More test)
The incontinence pad product was removed and tested.
i) The plate on which the incontinence pad was placed was inclined 45 °, and the incontinence pad was fixed by inclining the longitudinal direction of the incontinence pad further 45 ° in the plane of the plate from the inclination direction of the plate.
ii) A weighed filter paper was placed at the position where the liquid dipped under the 45 ° inclined plate.
iii) From the height of 1 cm above the center of the absorber, 40 ml of artificial urine was dropped into the absorber with a dropping funnel over 4 seconds.
iv) Artificial urine dripped onto the incontinence pad, flowing through the incontinence pad, and flowing out of the incontinence pad was sucked with a filter paper and weighed to obtain a “more amount”.
v) After 5 minutes of the initial dropping, the second dropping was performed and the same measurement was performed.

  The results of evaluation are shown in Tables 1 and 2. In Table 1 and Table 2, the value of the side part of “the composition of each layer of the absorber (basis weight)” is the basis weight of both the left and right sides, and “thickness of the absorber” is the center (the sum of the upper and lower layers). Thickness and side thickness.

According to Table 1, it can be seen that the incontinence pad of the example has a shorter absorption time, particularly a second absorption time, compared to the conventional incontinence pad.
According to Table 2, the incontinence pad of Example 1 showed no leakage in the 45 ° leakage test. On the other hand, the incontinence pad without the upper center layer of Comparative Example 2 has an excellent absorption rate as in Example 1, but leakage occurred in the 45 ° leakage test.
According to Table 2, the incontinence pad in which the absorbent core layer adjacent to both sides of the central lower layer (tow / SAP layer) of Comparative Example 3 does not exist has a slow second absorption rate, compared with the conventional product of Comparative Example 1. It can be seen that the effect of the improvement is small.

(Measurement of thickness and density of components of incontinence pad)
About the surface sheet, cushion material, and absorber (center upper layer, side part, center lower layer), which are the constituent members of the incontinence pad of Example 4, a predetermined measurement sample was collected, and the thickness and density were defined in advance. Measured by the method. Since the surface sheet and the cushion material are integrated by embossing, the thickness measured by peeling each separately becomes larger at high pressure, so the thickness of the surface sheet and cushion material that are peeled together is also thick. Was measured. For the absorber, the thickness and density of each of the central upper layer (absorbing core upper layer), side portions (both side absorbing core layers) and central lower layer (low-density skeleton layer) were measured.
The results are shown in Table 3.

From Table 3, it can be seen that the density is high in the following order at both low pressure and high pressure.
Side part (both side absorbent core layer)> Center upper layer (absorbent core upper layer)> (Top sheet + cushion material)> Center lower layer (low density skeleton layer)

In addition, the incontinence pads produced in all the examples were cut in the width direction near the center in the longitudinal direction and the cross section was observed, but it was clear that the order of thicknesses was also the following order by visual inspection. .
Center lower layer (low-density skeleton layer)> Side (both side absorbent core layers)> Center upper layer (center absorbent core layer)

(Example 5)
In Example 5, an incontinence pad having the same absorber as described in Example 1 was produced. However, as the design value, the amount of the central layer contains the amount and SAP 60 g / m ² pulp fibers in an amount of 49 g / m ^2, the central lower layer of SAP of 114 g / m ² amount and tow 180 g / m ² wherein, the sides were to include pulp fibers the amount and SAP 334 g / m ² in an amount of 410g / m ^2.

  Moreover, in Example 5, unlike Example 1, in producing the absorber, the width of the tow / SAP of the central lower layer was widened at both ends in the longitudinal direction as in the absorber shown in FIGS. Specifically, using a continuous fiber of tow opened as the central lower layer of the absorbent body, the longitudinal middle portion (length about 150 mm) is 30 mm wide, but in the longitudinal direction both ends (length about 50 mm), The tow was gradually widened from the width of 30 mm in the middle in the longitudinal direction toward both ends to make the width of the tip 85 mm, and the widened tow was overlapped with the side absorption core layer.

  About the absorber produced in Example 5, the center in the width direction in the width direction at the intermediate portion in the longitudinal direction (hereinafter referred to as the center portion C) and both end portions in the longitudinal direction (represented as the end portions A and B, respectively). The basis weight, thickness, and density of each part and both sides in the width direction (respectively expressed as side part 1 and side part 2) were measured.

  The basis weight was measured by extracting the absorbent core using a 20 × 10 mm die, measuring the mass, and calculating the basis weight (average value). The results are shown in Table 4. In the end portions A and B (both end portions in the longitudinal direction), it is recognized that the basis weight of the tow is slightly larger than the side portions 1 and 2 in the center portion in the width direction.

The thickness was measured with a Peacock H-type (10 mmφ, Ozaki Manufacturing Co., Ltd.). The thickness was measured immediately after pressing and after 2 days. The number of samples was 2 in each measurement of Example 5 and Example 6. Table 5 shows the measurement results of the thickness at both ends in the longitudinal direction of the absorber.
The density was measured and the results are shown in Table 6. (The basis weight, thickness, and density were arbitrarily measured at maximum 10 locations for each sample, and the average value was obtained.)

  About the incontinence pad of Example 5, the absorption characteristic was evaluated similarly to Examples 1-5, but it was confirmed that there is no substantial difference in an absorption characteristic compared with Examples 1-5.

(Examples 6 and 7)
Two incontinence pads similar to Example 1 were prepared. One of them (Example 7), like Example 5, widened the central lower layer at both longitudinal ends.

In the 50 mm long regions (corresponding to region 10 in FIG. 9) at both ends in the longitudinal direction of the absorbent body of the incontinence pad prepared in Examples 6 and 7, using a flat plate with a press machine, the pressure is 10 kg / cm ² . Pressed for 5 seconds. About this absorber, the thickness of the width direction center part and width direction both side part (each is described as the side part 1 and the side part 2) in a longitudinal direction both ends is each just after a press, and 2 days after. It was measured. The number of samples was 2. The thickness was measured with a Peacock H-type (10 mmφ, Ozaki Manufacturing Co., Ltd.). Table 7 shows the measurement results of the thickness at both ends in the longitudinal direction of the absorber.

  In the absorbent body in which the width of the tow (center lower layer) in Example 6 is substantially the same in the entire length direction, the change in the bulk (thickness) of the width direction center portion at the end portion in the length direction after the passage of time is large. Moreover, it is thought that although both the width direction both side parts (side parts 1 and 2) of a longitudinal direction both ends do not have tow and are only a pulp / SAP, it is easy to become hard although thickness maintenance property is high.

  On the other hand, in the absorbent body in which the width of the tow (center lower layer) in Example 7 was widened at both ends in the longitudinal direction, the tow was widened at both ends in the longitudinal direction, so that the time-lapse of the central portion in the width direction The change in bulk (thickness) is suppressed as compared with Example 6. Further, in the absorbent body of Example 7, both side portions (side portions 1, 2) in the width direction have a slightly large change in bulk (thickness) after aging, but the increase is slight, suppressing excessive crushing, and the end portions. It is thought that there is an effect of reducing hardness.

(Explanation of symbols)
1: incontinence pad, 2: top sheet, 3: back sheet, 4: absorber, 4C: center part in the width direction, 4S: both side parts in the width direction, 4M: middle part in the longitudinal direction, 4E: both end parts in the longitudinal direction, 41: Absorbent core, 42: Core wrap, 411: Low-density skeleton layer, 412: Central absorbent core upper layer, 413: Absorbent core layer on both sides, 5: Side sheet, 6: Elastic body, 7: Solid gather, 8: Cushion material, 9: pressing groove (hinge), 10: area

Claims (14)

A liquid-permeable top sheet disposed on the skin contact surface side, a liquid-impermeable back sheet disposed on the non-skin contact surface side, and a liquid interposed between the top sheet and the back sheet An absorbent article comprising a retaining absorbent and having a longitudinal direction and a width direction,
In the width direction, the absorbent body has a width direction center portion extending in the center in the length direction in the center, and width direction side portions extending in the length direction in both sides of the width direction center portion. The absorbent body is partitioned in the longitudinal direction in the longitudinal intermediate region and extends in the entire width in the width direction, and the width in the width direction on both sides of the lengthwise intermediate portion. Is divided into both longitudinal ends extending to
The absorbent body has 1) a central absorbent core upper layer on the surface sheet side of the longitudinal intermediate portion and both longitudinal end portions in the central portion in the width direction, and 2) the longitudinal portions on both side portions in the width direction. And having both side absorbent core layers adjacent to the central absorbent core upper layer on the surface sheet side of the intermediate portion in the direction and both ends in the longitudinal direction, and 3) the central portion in the width direction and the longitudinal direction of the intermediate portion in the longitudinal direction At least at the width direction central part of the both ends in the direction, it has a low density skeleton layer containing a hydrophilic fiber having crimps and a water absorbing material, and the low density skeleton layer is at least at the width direction central part. In the middle part in the longitudinal direction, the upper part is present on the back sheet side in contact with the central absorbent core upper layer,
The low-density skeleton layer has a density smaller than the density of each of the central absorption core upper layer and the both-side absorption core layers, and the low-density skeleton layer has at least a thickness of the middle portion in the longitudinal direction of the both-side absorption cores. An absorbent article having a thickness greater than the thickness of each of the layers, wherein the central absorbent core upper layer has a basis weight less than the basis weight of the side absorbent core layers.   The central absorbent core upper layer has a density smaller than the density of the both side absorbent core layers, the central absorbent core upper layer has a thickness smaller than the thickness of the both side absorbent core layers, and the central absorbent core upper layer The absorptive article according to claim 1 which has a basis weight smaller than a basis weight in at least said longitudinal direction middle part of said low-density skeleton layer.   The low-density skeleton layer is present on the back sheet side in contact with the central absorbent core upper layer at the widthwise central portion of both the longitudinal intermediate portion and both longitudinal end portions. Absorbent article as described in 1.   In at least one of the both ends in the longitudinal direction, the low-density skeleton layer continuously extends from the central portion in the width direction and also extends to both sides in the width direction. It exists on the back sheet side in contact with both side absorption core layers, and the maximum dimension in the width direction of the low-density skeleton layer at the at least one of the both ends in the longitudinal direction is the low-density skeleton layer in the intermediate portion in the longitudinal direction. The basis weight of the low-density skeleton layer in the at least one of the both ends in the longitudinal direction is smaller than the basis weight of the low-density skeleton layer in the intermediate portion in the longitudinal direction. 4. The absorbent article according to any one of items 3.   In the low density skeleton layer, the hydrophilic fibers are entangled with each other in a net shape, and the water absorbing material is supported between the hydrophilic fibers entangled in the net shape. The absorbent article of Claim 1.   The absorbent article according to any one of claims 1 to 5, wherein the hydrophilic fiber is a continuous filament of tow that is opened, and the continuous filament of the opened tow is arranged in the longitudinal direction. .   The absorbent article according to claim 6, wherein the low-density skeleton layer extends to both ends of the absorbent body in the longitudinal direction, and the continuous filaments of the opened tow are present to the both ends of the absorbent body.   The absorbent article according to any one of claims 1 to 7, wherein the water-absorbing material contained in the low-density skeleton layer is not fixed with an adhesive.   Each of the both side absorbent core layers and the central absorbent core upper layer includes pulp fibers and a superabsorbent polymer, and the hydrophilicity of the hydrophilic fibers contained in the low density skeleton layer is greater than the hydrophilicity of the pulp fibers. The absorptive article according to any one of claims 1 to 8 which is low.   The absorbent article according to any one of claims 1 to 9, wherein the water-absorbing material is a highly water-absorbing polymer.   The said absorbent article has a pressing groove from the said surface sheet to the said both-sides absorption core layer, The said pressing groove extends in the said longitudinal direction in the said width direction both sides, The any one of Claims 1-10 Absorbent article according to item.   The absorbent article according to any one of claims 1 to 11, wherein a density of the central absorbent core upper layer is larger than a density of the top sheet, and a density of the low-density skeleton layer is smaller than a density of the top sheet.   The center absorbent core upper layer has a cushion layer between the top sheet and the absorber, and the density of the low-density skeleton layer is smaller than the density measured by integrating the top sheet and the cushion layer. The absorbent article according to claim 1, wherein the density of the absorbent article is high.   The absorbent article according to any one of claims 1 to 13, which is an incontinence pad or a sanitary napkin.