JP2019103713A - Absorbent article - Google Patents

Abstract

To provide an absorbent article capable of suppressing liquid leaks in a rear portion.SOLUTION: An absorbent article according to one aspect of the present invention includes an absorbent core. The absorbent core includes a front core portion and a rear core portion located at both end sides in a longitudinal direction. The rear core portion has a structural surface which includes a plurality of vertical grooves arranged in a width direction orthogonal to the longitudinal direction and extending in the longitudinal direction. The structural surface includes: a pair of first regions which are located at both sides in the width direction and are occupied by the vertical grooves at a first ratio; and a second region which is located nearer to the center of the width direction than the first regions and is occupied by the vertical grooves at a second ratio greater than the first ratio.SELECTED DRAWING: Figure 4

Description

  The present invention relates to absorbent articles such as sanitary napkins.

  An absorbent article for absorbing a liquid such as menstrual blood is provided with an absorber having a longitudinal direction for absorbing the liquid. The absorbent has an absorbent core and a core wrap sheet covering the absorbent core. The absorbent core has a groove formed along the skin of the wearer wearing the absorbent article (see, for example, Patent Document 1).

JP, 2015-112235, A

  The sanitary napkin as the absorbent article is worn with its rear portion corresponding to the buttocks of the wearer. In particular, the sanitary napkin for the night is formed to have a long rear part in order to prevent liquid leakage in the rear part, and the rear part of the sanitary napkin is formed so as to substantially cover the buttocks. Since the buttocks portion has a shape in which the groin region is sharply depressed with respect to the swelling of the buttocks, a gap is easily generated between the groin and the sanitary napkin at the rear portion of the sanitary napkin. For this reason, a liquid substance such as menstrual blood excreted from the excretory area of the wearer may flow into the rear part with tearing, and liquid leakage may occur in the rear part.

  An object of the present invention relates to an absorbent article capable of suppressing liquid leakage in the rear portion.

An absorbent article according to an aspect of the present invention comprises an absorbent core.
The absorbent core has a front core portion and a rear core portion located on both end sides in the longitudinal direction.
The rear core portion has a structural surface including a plurality of longitudinal groove portions arranged in the width direction orthogonal to the longitudinal direction and extending in the longitudinal direction.
The structural surface is a pair of first regions located on both sides in the width direction and occupied by the longitudinal grooves at a first ratio, and a longitudinal groove located on the central side in the width direction with respect to the first regions. And a second region that occupies at a second ratio that is greater than the first ratio.

  As described above, according to the present invention, it is possible to suppress liquid leakage in the rear portion of the absorbent article.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the absorbent article of the 1st Embodiment of this invention. It is a top view of the above-mentioned absorptive article. It is sectional drawing cut | disconnected by the III-III line of FIG. It is a top view of the absorptive core of the above-mentioned absorptive article. It is the schematic which shows the deformation | transformation state of the napkin at the time of wearing the said absorbent article. It is a top view of the absorptive core of the absorptive article of a 2nd embodiment of the present invention. It is a top view of the absorptive core of the absorptive article of a 3rd embodiment of the present invention. It is a top view of the absorptive core of the absorptive article of a 4th embodiment of the present invention. It is a top view of the absorptive core of the absorptive article of a 5th embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the drawings, an X axis, a Y axis, and a Z axis are shown.

First Embodiment
[Whole composition of the napkin]
FIG. 1 is a perspective view showing an absorbent article 1 according to an embodiment of the present invention. In FIG. 1, the X-axis direction corresponds to the front-rear direction, the Y-axis direction corresponds to the left-right direction, and the Z-axis direction corresponds to the vertical direction.
FIG. 2 is a plan view of the absorbent article 1 and shows a mode in which the absorbent article 1 shown in FIG. 1 is stretched along the XY plane. In the absorbent article 1 shown in FIG. 2, the X-axis direction corresponds to the longitudinal direction, the Y-axis direction corresponds to the width direction, and the Z-axis direction corresponds to the thickness direction. Hereinafter, the absorbent article 1 is demonstrated in the aspect shown in FIG.
The absorbent article 1 of the present embodiment is configured as a sanitary napkin and hereinafter referred to as a napkin 1.
The napkin 1 of the present embodiment may be used at bedtime, and may have a length of, for example, 30 cm or more along the X-axis direction, which is the longitudinal direction.

  In the embodiment, the napkin 1 includes a main body M, a pair of wing portions W, a pair of side guards G, and a pair of rear flap portions F.

The main body M extends in the longitudinal direction and is fixed to the inner surface (mounted surface) of the underwear of the wearer when worn. The main body M has an absorber, which will be described later, and has a function of absorbing a liquid such as menstrual blood of the wearer (hereinafter, also referred to as “liquid”).
The main body M has a front area M1, an intermediate area M2, and a rear area M3 sectioned along the longitudinal direction.
The front area M1 is an area disposed in front of the middle area M2 (ventral side of the wearer), and is configured to face the front of the excretory area of the wearer at the time of wearing.
The middle area M2 is configured to face the excretory area of the wearer at the time of wearing. In the case of a napkin having a wing portion, a region in the longitudinal direction X overlapping the entire length of the wing portion is an intermediate region M2. In the case of the napkin which does not have a wing part, let the area | region of the center when the full length of a napkin is equally divided into 3 be the intermediate | middle area | region M2. The intermediate region M2 may be located closer to the front of the main body M as illustrated, or may be located at the central portion of the main body M.
The rear area M3 is an area disposed behind the intermediate area M2 (the back of the wearer), and is configured to face the rear of the wearer's excretion area when worn. In the present embodiment, the rear region M3 is formed to be longer in the longitudinal direction than each of the front region M1 and the middle region M2. Thereby, it is possible to effectively prevent the liquid leakage to the rear.

The wing portion W is configured to largely protrude outward in the width direction from the middle region M2.
The side guard G is arranged to extend in the longitudinal direction at the widthwise peripheral edge of the main body M including the intermediate region M2.
The rear flap portion F is configured to bulge outward in the width direction from the rear region M3 and can be fixed to the region facing the buttocks of the inner surface of the underwear of the wearer at the time of wearing. Thereby, the back flap part F can prevent position shift of back field M3 accompanying with operation of a wearer at the time of wearing, and can support a back leak prevention function by back field M3.
The napkin 1 may not have at least one of the wing portion W, the side guard G, and the rear flap portion F.

[Configuration of each part of the napkin]
FIG. 3 is a cross-sectional view taken along line III-III in FIG.
The napkin 1 includes an absorbent body 11, a top sheet 12, a back sheet 13, a pair of side sheets 14, an adhesive portion 15, and a pressing groove 16.
In addition, the main body M has the absorber 11, the surface sheet 12, and the back surface sheet 13, and has the structure on which these were laminated | stacked.

The absorber 11 has a longitudinal direction in the X-axis direction, and is disposed at the central portion in the thickness direction of the napkin 1. The absorber 11 absorbs the excreted liquid from the surface on the surface sheet 12 side, and diffuses the inside to hold the liquid.
The absorbent body 11 has an absorbent core 20 and a core wrap sheet 30.

The absorbent core 20 has a function to absorb and hold a liquid. The absorbent core 20 may be formed of, for example, a fiber assembly composed of hydrophilic fibers such as pulp fibers, or may have a configuration in which a water absorbing polymer is held by the fiber assembly. . The detailed configuration of the absorbent core 20 will be described later.
The absorbent core 20 has a first surface 20 a facing the top sheet 12 and a second surface 20 b facing the back sheet 13. In the present embodiment, the first surface 20a is configured as a structured surface having a convex structure or a groove, and the second surface 20b is configured as a flat surface.

  The core wrap sheet 30 covers the absorbent core 20 and has, for example, a function of holding the shape of the absorbent core 20. The core wrap sheet 30 is formed of, for example, thin soft paper such as tissue paper, liquid-permeable non-woven fabric, or the like.

  The surface sheet 12 is configured as a liquid-permeable sheet material and disposed on the absorber 11. The surface sheet 12 includes an outer surface 12 a which constitutes the surface (surface in the thickness direction) of the napkin 1 in the main body M.

  The back sheet 13 is disposed to face the top sheet 12 in the thickness direction with the absorber 11 interposed therebetween. The back surface sheet 13 includes the outer surface 13a which constitutes the back surface (surface under the thickness direction) of the napkin 1, and is disposed over the main body M, the wing portion W and the rear flap portion F.

  The pair of side sheets 14 oppose each other in the width direction with the top sheet 12 interposed therebetween, and are disposed at the widthwise peripheral edge of the napkin 1.

  The adhesive part 15 is a structure for fixing the napkin 1 to the undergarment, and is formed on the outer surface 13 a of the back sheet 13. The adhesive unit 15 includes, for example, a main unit adhesive unit 151 provided on the main body M, a wing adhesive unit (symbol 152 in FIG. 12 described later) provided on the wing unit W, and a rear flap adhesive unit 153 provided on the rear flap unit F. And.

The squeeze groove 16 is configured as a linear groove formed by squeezing the absorber 11 and the top sheet 12. The pressing groove 16 is configured to go around the main body M as shown in FIGS.
The squeeze groove 16 can induce deformation to a shape that fits the wearer at the time of wearing, and can enhance the effect of preventing liquid leakage outward in the width direction and longitudinal direction of the napkin 1.

[Detailed configuration of absorbent core]
FIG. 4 is a plan view showing the configuration of the absorbent core 20 that constitutes a part of the absorbent body 11. FIG. 4 is a plan view of the absorbent core 20 alone before being assembled as the napkin 1. Therefore, in the absorbent core 20 shown in FIG. 4, the grooves formed by the compressed grooves 16 are not formed.

(Whole structure of absorbent core)
The absorbent core 20 has a front core portion 21 and a rear core portion 23 mutually opposed in the longitudinal direction, and an intermediate core portion 22 located between the front core portion 21 and the rear core portion 23. The absorbent core 20 has a planar shape narrowed at the intermediate core portion 22. The front core portion 21 of the absorbent core 20 covers only the front region M1, the middle core portion 22 extends from the front region M1 to the rear region M3 via the middle region M2, and the rear core portion 23 only the rear region M3, It is arranged respectively.

The front core portion 21 and the rear core portion 23 are respectively disposed on both end sides in the longitudinal direction. The front core portion 21 and the rear core portion 23 may be respectively disposed in front of and behind the excretory area of the wearer at the time of wearing.
The middle core portion 22 is located between the front core portion 21 and the rear core portion 23 and has a narrower width than the front core portion 21 and the rear core portion 23.

  In the present embodiment, the front core portion 21 and the rear core portion 23 may have boundary portions 21 a and 23 a adjacent to the intermediate core portion 22 and decreasing in width toward the intermediate core portion 22. The boundaries 21a and 23a may be in a line symmetrical shape or an asymmetrical shape with respect to a symmetry axis parallel to the width direction. By providing the boundaries 21a and 23a, the deformation of the boundaries 21a and 23a with respect to the external force in the width direction can be suppressed, and the deformation of the intermediate core 22 can be effectively suppressed.

  The absorbent core 20 has a first surface 20a and a second surface 20b opposed to each other along the Z-axis direction which is the thickness direction.

  The first surface 20 a is a surface on which the top sheet 12 is disposed via the core wrap sheet 30. The outer surface 12 a of the top sheet 12 is a skin contact surface. When the napkin 1 is worn by the wearer, the first surface 20a is located on the skin side of the wearer.

  The second surface 20 b is a surface on the side on which the back sheet 13 is disposed via the core wrap sheet 30. The adhesive portion 15 formed on the outer surface 13a of the back sheet 13 is configured to be able to fix the napkin 1 to the inner surface of the undergarment. When the napkin 1 is worn by the wearer, the second surface 20b is located on the inner side of the undergarment. The second surface 20 b is substantially flat.

The first surface 20 a has a plurality of longitudinal grooves 27 and lateral grooves 28 intersecting with each other.
In the absorbent core 20, the longitudinal groove 27 and the lateral groove 28 are provided in line symmetry about a straight line extending in the longitudinal direction (X-axis direction) passing through the center of the width direction (Y-axis direction) of the absorbent core 20 .
The plurality of lateral grooves 28 are arranged in the longitudinal direction and extend in the width direction (Y-axis direction) orthogonal to the longitudinal direction.
The plurality of longitudinal grooves 27 are arranged in the width direction and extend in the longitudinal direction.

By providing the vertical groove 27 and the horizontal groove 28, the flexibility of the absorbent core 20 can be enhanced, and the liquid absorption speed can be increased by drawing the liquid into the groove. In addition, the absorbent core 20 is divided into a plurality of block portions 29 by the longitudinal grooves 27 and the lateral grooves 28, so that the surface area of the absorbent core 20 can be increased, and the liquid can be absorbed and held efficiently.
Each of the block portions 29 has a four-sided shape, a substantially fan-like shape, or a shape in which a part of a rectangle is cut in a plan view of the top of the block portion 29. The top of each block 29 is substantially flat.

  The first surface 20 a has a plurality of convex block portions 29 defined by the longitudinal grooves 27 and the lateral grooves 28. The absorbent core 20 has a concavo-convex structure attributable to, for example, a basis weight distribution on the first surface 20a. Since the basis weight has a correlation with the rigidity, by adjusting the basis weight distribution, it is possible to control the deformation of the absorbent core 20 with respect to the external force applied at the time of mounting.

The intermediate core portion 22 includes a high basis weight portion 24 and a pair of low basis weight portions 25. In FIG. 4, the high basis weight portion 24 is shown by a dense dot pattern, and the low basis weight portion 25 is shown by a rough dot pattern.
Of the block portions 29 disposed in the intermediate core portion 22, the high basis weight portion 24 is configured by the block portion group arranged in the central two rows. The low basis weight portion 25 is constituted by a group of block portions arranged one by one on both sides of the high basis weight portion 24.
The high basis weight portion 24 has a high basis weight relative to the low basis weight portion 25.
The high basis weight portion 24 may be arranged to face the excretory area of the wearer at the time of wearing.

  As shown in FIG. 4, the first surface 20 a is a front structural surface 51 located at the front core portion 21, a liquid receiving surface 52 located at the intermediate core portion 22, and a rear structural surface located at the rear core portion 23. And 53. The front structural surface 51 is adjacent to the liquid receiving surface 52. The rear structural surface 53 is adjacent to the receiving surface 52.

The front structural surface 51 and the rear structural surface 53 have a shape in which a plurality of grooves are formed on a flat surface.
On the liquid receiving surface 52, the high basis weight portion 24 is shaped so as to protrude upward in the thickness direction from the low basis weight portion 25, the front core portion 21 and the rear core portion 23. Each of the high basis weight portion 24 and the low basis weight portion 25 has a shape in which a plurality of grooves are formed on a flat surface.
In addition, it may replace with the form of FIG. 3, and the form which the high basic weight part 24 protrudes below a Z direction may be sufficient. In that case, when sticking on underwear, the convex structure which protruded below via a back surface sheet is pushed up, and it becomes the structure similar to the form of FIG.

In the absorbent core 20, the regions in which the grooves 27 and 28 are formed, that is, the bottoms forming the grooves 27 and 28 are relatively thicker than the block 29 in which the grooves 27 and 28 are not formed. The thickness in the (Z-axis direction) is thin.
The thickness and basis weight of the absorbent core 20 are in correlation. The bottoms forming the grooves 27 and 28 have a relatively low basis weight as compared to the block 29. As a result, the bottoms of the grooves 27 and 28 have lower rigidity than the block 29. Therefore, when an external force is applied to the absorbent core 20, the absorbent core 20 is easily deformed with the grooves 27 and 28 as the deformation starting point.
From the viewpoint of ease of deformation, it is desirable for each groove to have a basis weight of the absorbent material smaller than that of the surrounding block. Here, "low basis weight" is a concept including a form in which the material of the absorbent core is present as well as a form in which the material of the absorbent core is not present. However, in the form in which the material of the absorbent core is present, since the block-like portions of the absorbent core located on both sides are connected via the respective grooves, the absorbent core moves by swaying, breaking and breaking by thousand. It is more preferable because breakage and the like can be prevented and flexibility can be imparted.

  In the present embodiment, each groove is substantially the same as the groove width at the bottom forming the groove and the groove width at the opening of the groove. The bottom of the groove is located substantially parallel to the second surface 20b. The side of the groove forming the groove is substantially perpendicular to the bottom. The width of the groove described below indicates the width at the opening of the groove.

  In addition, although a groove part demonstrates the example which the cross section orthogonal to the longitudinal direction of a groove part substantially rectangular shape here, it is not limited to this. For example, the V-shaped or trapezoidal groove may have a V-shaped or trapezoidal cross section having a tapered side surface whose width increases from the bottom toward the opening. Even in such a case, in the absorbent core 20, the area in which the grooves are formed has a lower basis weight and lower rigidity than the area in which the grooves are not formed. For example, in the case of a V-shaped or trapezoidal groove, the width of the groove indicates the width at the opening.

(Structure of rear structural surface)
Next, the longitudinal grooves and the lateral grooves disposed in the rear structural surface 53 will be described in detail. The absorbent core 20 has flutes of two different widths.

  Hereinafter, in the present embodiment and other embodiments described later, when the absorbent core has the longitudinal grooves 27 with different widths, the relatively wide longitudinal groove is referred to as a second longitudinal groove 272 as a large longitudinal groove, A narrow vertical groove may be referred to as a first vertical groove 271 as a thin vertical groove. Moreover, when all the several vertical groove parts are the same width, it only calls the vertical groove part 27, and demonstrates. In addition, when it is not necessary to distinguish the 1st vertical groove part 271 and the 2nd vertical groove part 272 in particular, all are called the vertical groove part 27. FIG.

The rear structural surface 53 has five longitudinal grooves 27 and lateral grooves 28.
The five longitudinal grooves 27 are spaced apart from each other, arranged at an equal arrangement pitch in the width axis direction, and extend in the width direction. Here, the arrangement pitch is the distance between the centers of adjacent longitudinal grooves.

In the rear structural surface 53, the five longitudinal grooves 27 include two first longitudinal grooves 271 and three second longitudinal grooves 272.
The first vertical groove 271 is a vertical groove positioned one on each of the left and right sides of the five vertical grooves 27.
The second longitudinal groove portion 272 is three longitudinal groove portions located in the central portion among the five longitudinal groove portions 27.
The second vertical groove portion 272 is a groove portion wider than the first vertical groove portion 271.

As shown in FIG. 4, the rear structural surface 53 has a pair of first regions 238 located on both sides in the width direction, and a second region 237 located on the center side in the width direction than the first regions 238. Have.
The first regions 238 are located on both sides in the width direction among the regions obtained by equally dividing the rear core portion 23 in the Y-axis direction.
The second area 237 is located at the center in the width direction among the three equally divided areas. The second area 237 is located between the pair of first areas 238.
The second area 237 is an area on the center side including the center line that bisects the absorbent article in the width direction, and in the intermediate core section 22 is an area including a portion facing the excretory part of the wearer, The portion 23 is a region including a portion facing the groin 61.

A pair of first longitudinal groove portions 271 disposed opposite to each other via the second longitudinal groove portions 272 is arranged one by one in each of two first regions 238.
One second vertical groove 272 positioned at the center among the three second vertical grooves 272 is arranged in the second region 237.
Two second longitudinal grooves 272 positioned on both sides of the three second longitudinal grooves 272 are arranged across the first area 238 and the second area 237, respectively.

The first longitudinal groove 271 and a part of the second longitudinal groove 272 positioned on both sides of the three second longitudinal grooves 272 occupy the first region 238 at a first ratio.
The remaining portions of the central second longitudinal groove portion 272 and the second longitudinal groove portions 272 located on both sides of the three second longitudinal groove portions 272 occupy the second region 237 at a second ratio.

In the present embodiment, since all the longitudinal grooves have a shape extending in the front-rear direction with equal width, the first ratio is the first region with respect to the dimension of the first region 238 in the width direction. It can be shown by the ratio of the sum of the width dimensions of the flutes arranged at 238.
The second ratio can be expressed as a ratio of the total width dimension of the flutes arranged in the second region 237 to the width dimension of the second region 237.

The second ratio is greater than the first ratio.
As described above, in the absorbent core 20, the bottom of the longitudinal groove 27 is thinner than the block 29. Therefore, by making the second ratio larger than the first ratio, in the width direction, the ratio of the region where the thickness of the absorbent core is thinner in the second region 237 is higher than that of the first region 238. Become. As a result, the second region 237 located at the center in the width direction has lower rigidity than the first regions 238 located on both sides.
As a result, when the napkin 1 is attached and an external force is applied to the absorbent core 20, the second region 237 is more likely to be deformed preferentially in the rear core portion 23 than the first region 238.

  Thus, in the present embodiment, by making the widths of the plurality of longitudinal grooves arranged in the rear core portion 23 different depending on the area, the distribution ratio of the longitudinal grooves in the width direction of the rear core portion 23 is adjusted. .

When the groove width of the vertical groove is not constant in the front-rear direction, the occupancy ratio of the vertical groove can be obtained as follows.
A virtual line segment extending in the width direction (Y-axis direction) and having the same length as the width of the rear core portion 23 is provided at an arbitrary position of the rear core portion 23. This virtual line segment has three divided virtual line segments formed by dividing the virtual line segment into three, corresponding to the respective regions of the pair of first region 238 and second region 237. A plurality of virtual line segments can be set over the entire length of the rear core portion 23. For example, 20 virtual line segments are set here.

  The first ratio, which is the occupancy ratio of the vertical groove in the first region 238, can be determined as follows. That is, the ratio of the total of the groove width on one divided imaginary line with each vertical groove located in the first region 238 to the length of the divided imaginary line segment occupies the vertical groove on one divided imaginary line It becomes a ratio. Since 20 virtual line segments are set, the occupation ratio of the vertical groove in the first area 238 is similarly determined on the 20 divided virtual lines. The first ratio is obtained by averaging the 20 occupancy ratios obtained on each divided virtual line.

  The second ratio, which is the occupancy ratio of the vertical groove in the second region 237, can be determined as follows. That is, the ratio of the total of the groove width on one divided imaginary line with each vertical groove located in the second region 237 to the length of the divided virtual line segment occupies the vertical groove on one divided imaginary line It becomes a ratio. Since 20 virtual line segments are set, the occupancy ratio of the vertical groove in the second region 237 is similarly determined on the 20 divided virtual lines. The second ratio is obtained by averaging the 20 occupancy ratios obtained on each divided virtual line.

  The rear structural surface 53 has a total of 36 block portions 29 divided into six rows in the longitudinal direction and six rows in the width direction by the lateral grooves 28 and the longitudinal grooves 27. These block portions 29 have a quadrangular top portion in plan view. Hereinafter, the dimension at the block portion is the dimension at the top of the quadrilateral shape of the block portion. The number of block portions of the rear structural surface 53 is not limited to this. The number of block portions can be easily changed by changing the number or the like of the lateral groove portions 28 in accordance with the longitudinal length of the rear structural surface 53.

In regard to the block portions 29 located in the rear core portion 23, each block portion 29 of the block portion group located in the center 2 rows is denoted by reference numeral 292, and the block portions 29 located in the center 2 rows The respective block portions 29 of the pair of block portion groups arranged opposite to each other will be described with reference numeral 291.
Each block portion 291 is located in the first area 238, and each block portion 292 is located in the second area 237.

  Hereinafter, in the present embodiment and other embodiments described later, the block portion 29 in the first region 238 is referred to as a block portion 291, and the block portion 29 in the second region 237 is referred to as a block portion 292 as necessary. May distinguish. In addition, when it is not necessary to distinguish the block part 291 and the block part 292 in particular, both are called the block part 29.

  The lateral grooves 28 are arranged at equal intervals on the rear structural surface 53 so that the dimensions of the sides in the longitudinal direction (X-axis direction) of the respective block portions 29 on the rear structural surface 53 are the same.

The dimension of the block portion 292 in the width direction is shorter than the dimension of the block portion 291 in the width direction.
Of the block portions 291 located in the first region 238, the block portions 291 of the pair of block portions located immediately on either side of the two rows of block portions located in the second region 237 are located at the outermost side. The dimensions in the width direction are shorter than the respective block portions 291 of the pair of block portion groups.

The above-mentioned absorbent core 20 is typically a mixed-stack fiber body obtained by mixing and stacking pulp fibers and an absorbent polymer.
Examples of hydrophilic fibers contained in the absorbent core 20 include pulp fibers, rayon fibers, cotton fibers, cellulose-based hydrophilic fibers such as cellulose acetate, polyolefin fibers such as polyethylene and polypropylene, condensation of polyesters, polyamides, etc. It is possible to use one or two or more selected from the group fibers and the like.
As the water absorbing polymer contained in the absorbent core 20, for example, sodium polyacrylate, acrylic acid-vinyl alcohol copolymer, sodium polyacrylate cross-linked product, starch-acrylic acid graft copolymer, isobutylene-maleic anhydride One or more selected from copolymers and saponified products thereof, polyaspartic acid and the like can be used.

  The absorptive core 20 which has an uneven structure in the above-mentioned back structure surface 53 can be manufactured, for example using the fiber-stacking apparatus provided with the fiber-stacking drum which has the recessed part for accumulation | storage in an outer peripheral surface. In the fiber stacking apparatus, the core material is deposited in the accumulation recess by supplying the core material such as pulp fiber to the outer peripheral surface of the fiber stacking drum. An absorbent core can be obtained by releasing the deposited fiber body from the accumulation recess.

[Operation and effect of this embodiment]
FIG. 5 is a schematic view for explaining the relationship between the groin 61 of the collar part 60 of the wearer and the deformed state of the rear region M3 of the napkin 1 when the napkin 1 of the present embodiment is worn.

  As described above, in the present embodiment, the second longitudinal groove portion 272 which is a large longitudinal groove portion is arranged at the central portion in the width direction of the rear core portion 23, and the first longitudinal groove portion 271 which is a fine longitudinal groove portion on both sides. Are arranged such that the occupation ratio (second ratio) of the vertical groove in the second region 237 is larger than the occupation ratio (first ratio) of the vertical groove in the first region 238. Ru.

  Thereby, in the rear core portion 23 of the absorbent core 20, the ratio of the region where the thickness of the absorbent core 20 is thinner in the width direction is higher in the second region 237 than in the first region 238. . Therefore, in the rear core portion 23, the center at which the second region 237 is located is lower in rigidity than the two sides at which the first region 238 is located, and is easily deformed.

  Thereby, as shown in FIG. 5, when the napkin 1 is attached, the second area 237 is likely to be deformed so as to project to the first surface 20 a side preferentially to the first area 238. Therefore, when the napkin 1 is attached, the center of the rear core portion 23 protrudes toward the skin, and the napkin 1 is easily deformed such that the protruding portion is along the crease 61. As a result, the gap between the torn 61 and the napkin 1 can be reduced, and liquid leakage at the rear of the napkin 1 is suppressed.

  Furthermore, since the longitudinal groove portion is arranged in the first region 238, it is likely to follow the second region 237 which is preferentially deformed, and to be deformed along the bulge of the buttocks. As a result, the gap between the buttocks and the absorbent article is reduced, the fit is improved, and the lateral leakage of the rear portion is suppressed.

  In addition, since the first region 238 has high rigidity and is less likely to be deformed as compared with the second region 237, even if the second region 237 of the absorbent core 20 is deformed along the crease 61, In conjunction with the deformation of the second area 237, the first area 238 does not deform excessively. Therefore, the twist in the back core part 23 of the absorptive core 20 at the time of wearing of the napkin 1 is suppressed.

  As described above, in the napkin 1 of the present embodiment, the rear region thereof is easily deformed along the shape of the buttocks including the groin, and furthermore, it is possible to suppress the twist. As a result, even if a liquid such as menstrual blood of the wearer flows out to the rear core portion 23 of the napkin 1, it is absorbed quickly by the absorber 11 deformed along the crease 61 and leakage is suppressed. Liquid leakage due to In particular, when the napkin is worn in a supine position by the wearer at bedtime, the liquid easily flows to the back on the back side, so the napkin 1 of the present embodiment is effective in suppressing liquid leakage at night in the rear. is there.

  Further, in the present embodiment, the second region 237 which is easily deformed is formed to have a certain width, for example, about 1/3 the width D of the rear core portion 23. Thus, even if the napkin 1 is worn with a gap in the width direction, for example, the second region 237 is disposed corresponding to the groin 61 and is deformed to a shape along the groin 61. Therefore, a gap does not easily occur between the napkin 1 and the skin, and leakage is suppressed.

Further, in the present embodiment, in the rear core portion 23, the area of each block portion 292 of the second region 237 is the same as that of each block portion 291 except for the block portion 291 having the boundary portion 23 a of the pair of first regions 238. Smaller than the area.
Specifically, since the dimensions in the longitudinal direction of the block portion 292 and the block portion 291 are the same, the dimension in the width direction of the block portion 292 is shorter than the dimension in the width direction of the block portion 291.
Here, the area of the block portion refers to the area of the top of the quadrilateral block portion in plan view.

Thus, the area of the block portion 292 disposed in the second region 237 positioned at the central portion in the width direction is relatively reduced, in other words, by shortening the dimension in the width direction of the block portion 292, The second vertical groove portions 272 located between the block portions 292 adjacent in the width direction tend to be the deformation starting point, and deformation is less likely to occur in the block portions 292.
Therefore, when the napkin 1 is attached, the napkin 1 is likely to be deformed into an ideal shape along the groin.

  Further, in the present embodiment, since the lateral groove portion 28 is disposed in addition to the longitudinal groove portion 27, in the longitudinal direction of the napkin 1, it is easily deformed along the shape of the wearing target portion of the wearer, and the fit property is improved.

[Additional explanation of this embodiment]
Hereinafter, the description of the present embodiment will be supplemented.

(Measurement method of groove width)
The width of the groove is determined by measuring the width at the opening of the groove. The absorbent core is placed horizontally, the measurement magnification is adjusted with a microscope (VHX-1000 manufactured by KEYENCE Corporation), and the first surface 20 a is enlarged to measure the opening width.
Alternatively, the absorbent core 20 is cut using a feather blade razor and the cross section of the cut sample is observed at a magnification of 20 to 100 times using a microscope (VHEX-1000 manufactured by KEYENCE Corporation), The groove width may be measured. The thickness of the bottom of the groove and the thickness of the block can also be measured in the same manner.

(Method of measuring the basis weight of each part of the absorbent core)
Each part of the absorber 11 to be measured is cut using a feather blade razor manufactured by Feather Inc., and pieces are obtained so as to have a predetermined area. The weight of the small pieces is measured using an electronic balance (electronic balance GR-300, manufactured by A & D, accuracy: 4 digits after the decimal point). The weight determined is divided by the area of the small pieces of each part to calculate the basis weight of the small pieces. For each part, the average of the basis weight of 5 pieces is taken as the basis weight.

(Method of measuring thickness of each part of absorbent core)
The thickness of the absorbent core 20 to be measured is measured by measuring the thickness of small pieces cut out to measure the basis weight for each part. The small pieces cut out from the absorbent core are pressurized at a pressure of 5 kPa for 10 minutes, and measurement is carried out immediately after weight removal. Place an acrylic plate with a size of 20 mm × 20 mm and a thickness of 3 mm in the central area of the sample after weight removal, and use the KEYENCE non-contact laser displacement meter (laser head LK-G30, displacement meter LK-GD500) to sample Measure the thickness of When the size of the cut-out piece is small and difficult to measure by a non-contact laser displacement meter, the section of the cut sample is, for example, 20 to 100 using a microscope (VHX-1000 manufactured by KEYENCE Corporation). It may be observed at double magnification and measured.

(Example of each configuration)
The numerical example of the said absorptive core is demonstrated. In addition, it is not limited to the numerical value described here. The second ratio may be larger than the first ratio, and the first ratio and the second ratio, the width of the groove, and the like may be the width of the absorbent core, the depth of the groove, the bottom of the groove, and the like. It is suitably set according to the thickness of the block part. The thickness of the bottom of the groove and the block are correlated with the basis weight. The thickness and the basis weight of the bottom of the groove and the block are appropriately set so as to obtain a sufficient amount of absorption while providing a comfortable wearing feeling with an appropriate thickness that does not make the wearer feel uncomfortable.

The first ratio is preferably 10% or more and 21% or less, more preferably 11% or more and 20% or less, and is 16% in the present embodiment.
The second ratio is preferably 20% or more and 34% or less, more preferably 22% or more and 30% or less, and is 25% in the present embodiment.
The second ratio is preferably 1.1 times or more and 3 times or less, more preferably 1.3 times or more and 2.7 times or less of the first ratio.

The dimension in the width direction of the block portion 292 of the block units in the central two rows arranged in the second region 237 of the rear core portion 23 is, for example, 8.5 mm or more and 10.5 mm or less. did.
The dimension in the width direction of each block portion 291 of a pair of block portion groups adjacent to the central two rows of block portion groups of the rear core portion 23 and opposed via the central two rows of block portion groups is, for example, 10 mm or more It is 11.5 mm or less, and was 11 mm in this embodiment.
The dimension in the width direction of each block portion 291 of the pair of block portion groups positioned on the outermost side of the rear core portion 23 is, for example, 10.7 mm or more and 12.3 mm or less, and is 11.5 mm in this embodiment.

The width D of the rear core portion 23 is, for example, 60 mm or more and 100 mm or less, and is 80 mm in the present embodiment. The width of the rear core portion 23 is the width at the first surface 20a.
The arrangement pitch of the vertical groove portions 27 arranged in the rear core portion 23 is, for example, 11 mm or more and 15 mm or less, and is 13 mm in the present embodiment.

The width a of the first longitudinal groove 271 which is a fine longitudinal groove is preferably 0.5 mm or more and 2.5 mm or less, more preferably 1 mm or more and 2 mm or less, in order to make the rear portion soft and easy to deform along the buttocks. In the present embodiment, it is 1.5 mm.
The width b of the second longitudinal groove 272, which is a large longitudinal groove, is preferably 2.5 mm or more and 5.5 mm or less, and more preferably, in order to facilitate bending along the buttocks along the center and to have sufficient strength. Is 3 mm or more and 5 mm or less, and is 4 mm in this embodiment.

  The groove depth d1 of the first vertical groove 271, the second vertical groove 272, and the horizontal groove 28 is 1.5 mm or more and 6.0 mm or less, and is 4 mm in the present embodiment. The groove depth indicates the distance from the opening to the bottom of the groove located on the same plane as the top of the block.

The thickness of the bottom of the lateral groove 28 and the longitudinal groove 27 is, for example, 0.5 mm or more and 6.0 mm or less. The basis weight of the bottom surface of the horizontal groove portion 28 and the vertical groove portion 27 is, for example, 25 g / m ² or more and 300 g / m ² or less.
The thickness of the block portion of the rear core portion 23 is, for example, 2 mm or more and 10.0 mm or less. The basis weight of the block portion of the rear core portion 23 is, for example, 100 g / m ² or more and 500 g / m ² or less.

Other Embodiments
The form of the grooves arranged on the rear structural surface of the rear core portion is not limited to the first embodiment.
Hereinafter, second to fourth embodiments will be described as examples of other embodiments.

As in the case of the absorbent core 20 of the first embodiment, each of the absorbent cores shown in the following embodiments has the first surface and the second surface facing each other along the thickness direction. When the absorbent core is incorporated into a napkin, it has a groove on the first surface on which the top sheet is disposed.
The plan view of the absorbent core used in the description of each embodiment corresponds to the plan view on the first surface side where the grooves are arranged.

  In the absorbent core shown in each of the following embodiments, the occupancy ratio (second ratio) of the vertical groove portion arranged in the second region 237 located at the center is a pair of both sides of the second region 237. It is configured to be larger than the occupancy ratio (first ratio) of the vertical groove portions arranged in the first region 238.

  Thereby, the second region 237 is more likely to be deformed preferentially than the first region 238 when the napkin incorporating such an absorbent core is worn. Therefore, the napkin protrudes on the first surface side in the second region 237 toward the skin, and the protruding portion is easily deformed so as to be along the groin 61. This makes it possible to reduce the gap between the torn 61 and the napkin and to suppress liquid leakage at the rear of the napkin.

  Furthermore, since the longitudinal grooves are arranged in the first area 238, the first area 238 follows the second area 237 that deforms preferentially, and tends to deform along the bulge of the buttocks. As a result, the gap between the buttocks and the absorbent article is reduced, the fit is improved, and the lateral leakage of the rear portion is suppressed.

  In addition, since the first region 238 has high rigidity and is less likely to be deformed as compared with the second region 237, even if the second region 237 is deformed along the groin 61, the second region 237 In conjunction with the deformation of the first region 238, the first region 238 is not deformed too much. Therefore, the twist in the back core part 23 of the absorptive core 20 at the time of wearing of the napkin 1 is suppressed.

  Hereinafter, in each embodiment, a configuration different from that of the first embodiment will be mainly described, and the same configuration is denoted by the same reference numeral, and the description thereof will be omitted.

Second Embodiment
In the absorbent core 20 of the first embodiment, the second ratio is configured to be larger than the first ratio by making the widths of the plurality of longitudinal grooves 27 different depending on the region.

On the other hand, in the absorbent core 120 of the present embodiment, the widths of the longitudinal grooves 27 arranged in the rear core portion 23 are all the same, and the arrangement pitch of the longitudinal grooves 27 is the first region 238 and the second region The second ratio is configured to be larger than the first ratio by differentiating between 237 and 237 and changing the number of the vertical groove portions 27 arranged in each region.
As described above, in the present embodiment, the distribution ratio of the longitudinal grooves 27 in the width direction (Y-axis direction) of the rear core portion 23 is made different by changing the number of the longitudinal grooves 27 arranged according to the area of the rear core portion 23. I'm adjusting.

A second embodiment will be described with reference to FIG. FIG. 6 is an example of a plan view of the absorbent core 120 that constitutes a part of the napkin.
Hereinafter, configurations different from the first embodiment will be mainly described, the same configurations as those described above may be denoted by the same reference numerals, and the description thereof may be omitted.

As in the first embodiment, the rear structural surface 53 is divided into three equal portions in the width direction, and a pair of first regions 237 located at the center, and a pair of first regions 237 located on both sides of the second regions 237. Region 238 of FIG.
Seven longitudinal grooves 27 are arranged in the rear structural surface 53.
Two longitudinal grooves 27 among the seven longitudinal grooves 27 are arranged one by one in each of the pair of first regions 238. In each first area 238, one flute 27 occupies the first area 238 in a first ratio.
The remaining five flutes 27 are arranged in the second region 237. The five longitudinal grooves 27 occupy the second area 237 at a second ratio.
The seven longitudinal grooves 27 all have the same width, for example, the same width of 1.5 mm as the first longitudinal groove 271 of the first embodiment.

The rear structural surface 53 has a total of 48 block portions 29 divided into six rows in the longitudinal direction (X-axis direction) and eight rows in the width direction (Y-axis direction) by the lateral groove portions 28 and the longitudinal groove portions 27. Have.
In the second area 237, 24 block portions 292 located in the central four rows are arranged.
Twelve block portions 291 are arranged in each of the pair of first regions 238.

In the present embodiment, in the rear core portion 23, the area of each block portion 292 of the second region 237 is the area of each block portion 291 excluding the block portion 291 having the boundary portion 23a of the pair of first regions 238. Too small.
Specifically, since the lateral groove portion 28 is provided such that the dimensions in the longitudinal direction of the block portion 292 and the block portion 291 are the same, the dimension in the width direction of the block portion 292 is the width of the block portion 291 It is shorter than the dimension in the direction.

Thus, the area of the block portion 292 disposed in the second region 237 positioned at the central portion in the width direction is reduced, in other words, by shortening the dimension in the width direction of the block portion 292 The longitudinal groove portions 27 located between the adjacent block portions 292 are likely to be deformation starting points, and deformation is less likely to occur in the block portions 292.
Therefore, when the napkin 1 is attached, the napkin 1 is likely to be deformed into an ideal shape along the groin.

Third Embodiment
FIG. 7 is an example of a plan view of the absorbent core 220 that constitutes a part of the napkin in the present embodiment. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

The rear structural surface 53 of the absorbent core 220 is equally divided into five in the width direction (Y-axis direction), a pair of first first regions 238, one second region 237, and a pair of first regions 238. And a third region 239.
The pair of first regions 238 is located on both sides in the width direction. The pair of first regions 238 is disposed opposite to each other via the second region 237 and the third region 239.
The second area 237 is located on the center side in the width direction among the five equally divided areas.
The pair of third regions 239 are disposed to face each other via the second region 237. The third area 239 is located between the first area 238 and the second area 237.

  In the rear structural surface 53, nine longitudinal grooves 27 having the same width are arranged. The longitudinal groove 27 has a width of 1.5 mm similar to that of the first longitudinal groove 271 of the first embodiment, for example.

One longitudinal groove 27 is arranged in each of the pair of first regions 238. The longitudinal groove 27 occupies each first area 238 at a first ratio.
Three longitudinal grooves 27 are arranged in the second region 237. The three longitudinal grooves 27 occupy the second area 237 at a second ratio.
Two longitudinal grooves 27 are arranged in each of the pair of third regions 239. The two longitudinal grooves 27 occupy the respective third regions 239 at a third ratio. The third ratio indicates the ratio of the total dimension of the width of the flutes arranged in the third region 239 to the dimension in the width direction of the third region 239.

As described above, in the absorbent core 220 of the present embodiment, the widths of the longitudinal groove portions 27 arranged in the rear structural surface 53 are all the same, and each of the rear structural surface 53 is divided into five in the width direction. The number of the longitudinal grooves 27 arranged in the area is configured to increase stepwise from both sides in the width direction toward the central part.
Therefore, the occupancy ratio (third ratio) of the longitudinal groove 27 in the third region 239 is larger than the occupancy ratio (first ratio) of the longitudinal groove 27 in the first region 238, and in the second region 237 It is configured to be smaller than the occupation ratio (second ratio) of the vertical groove 27.
Thereby, in the back core part 23 of the absorptive core 220, rigidity becomes low gradually toward the center from the both sides of the width direction, and it becomes a structure which is easy to deform | transform.

  In the napkin provided with such an absorbent core 220, the second region 237 preferentially deforms more than the first region 238 and the third region 239 when worn. Therefore, the second region 237 protrudes on the first surface side, and the napkin 1 is easily deformed so that the protruding portion is along the crease 61. This makes it possible to reduce the gap between the torn 61 and the napkin and to suppress liquid leakage at the rear of the napkin.

  Furthermore, by providing a third area 239 that is more deformable than the first area 238 and less deformable than the second area 237, the absorbent core 220 has a width from the center to the side. The ease of deformation changes gradually in the direction. As a result, the deformation of the absorbent core 220 corresponding to the area from the groin to the swelling of the buttocks becomes gentle, and the fit is further improved.

Fourth Embodiment
FIG. 8 is a plan view example of the absorbent core 320 which constitutes a part of the napkin in the present embodiment. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

  The rear structural surface 53 of the absorbent core 320 is, similarly to the third embodiment, a pair of first regions 238 equally divided into five in the width direction (Y-axis direction), and one second It has a region 237 and a pair of third regions 239.

In the rear structural surface 53, five longitudinal grooves 27 having different width dimensions are arranged.
In each of the pair of first regions 238, a first longitudinal groove 271 which is a thin longitudinal groove is arranged one by one. The first vertical groove 271 occupies the first area 238 at a first ratio.
In the second region 237, a second longitudinal groove portion 272 which is one thick longitudinal groove portion is arranged. The second longitudinal groove 272 occupies the second area 237 at a second ratio.
In each of the pair of third regions 239, third longitudinal groove portions 273 which are thick longitudinal groove portions are arranged one by one. The third longitudinal groove 273 occupies the third region 239 at a third ratio. The third ratio indicates the ratio of the total dimension of the width of the flutes arranged in the third region 239 to the dimension in the width direction of the third region 239.

  Although the second vertical groove portions 272 arranged in the second region 237 and the third vertical groove portions 273 arranged in the third region 239 are both thick vertical groove portions, the widths are different. The second longitudinal groove portion 272 of the second region 237 is wider than the third longitudinal groove portion 273 of the third region 239.

  In the absorbent core 320 of the present embodiment, the number of the longitudinal groove portions 27 arranged in each region when dividing the rear structural surface 53 into five equal parts in the width direction is also one in all. Furthermore, the width of the longitudinal groove portions 27 arranged in each region gradually widens from the both sides to the central portion in the width direction of the rear core portion 23, and is arranged at the center in the width direction. Is the widest.

  In this manner, the absorbent core 320 can be formed longitudinally in the third area 239 by making the widths of the longitudinal grooves 27 arranged in the first area 238, the second area 237, and the third area 239 different. The occupancy ratio (third ratio) of the groove 27 is larger than the occupancy ratio (first ratio) of the longitudinal groove 27 in the first region 238, and the occupancy ratio of the longitudinal groove 27 in the second region 237 (second Is configured to be smaller than the ratio of

  As a result, the rear core portion 23 of the absorbent core 320 has a structure in which the rigidity is gradually lowered from the both sides in the width direction toward the center, and the structure is easily deformed.

  In a napkin provided with such an absorbent core 320, the second area 237 preferentially deforms more than the first area 238 and the third area 239 when worn. Therefore, the second region 237 protrudes on the first surface side, and the napkin 1 is easily deformed so that the protruding portion is along the crease 61. This makes it possible to reduce the gap between the torn 61 and the napkin and to suppress liquid leakage at the rear of the napkin.

  Furthermore, by providing the third area 239 which is more deformable than the first area 238 and less deformable than the second area 237, the absorbent core 320 is formed in the width direction from the center to both sides. The ease of deformation changes in stages. As a result, the deformation of the absorbent core 320 corresponding to the area from the groin to the swelling of the buttocks becomes gentle, and the fit is further improved.

Fifth Embodiment
FIG. 9 is a plan view example of the absorbent core 420 which constitutes a part of the napkin in the present embodiment. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

  Similarly to the first embodiment, the rear structural surface 53 of the absorbent core 420 is divided into three equal parts in the width direction (Y-axis direction), and a second region 237 located at the center, the second It has a pair of first regions 238 which are both sides of the region 237.

In the rear structural surface 53, seven longitudinal grooves 27 having the same width are arranged. The arrangement pitch of the seven longitudinal grooves 27 gradually increases from the second area 237 toward the first area 238.
Four longitudinal grooves 27 of the seven longitudinal grooves 27 are arranged two by two in each of the pair of first regions 238. In each first area 238, the two flutes 27 occupy the first area 238 in a first ratio.
The remaining three flutes 27 are arranged in the second region 237. The three longitudinal grooves 27 occupy the second area 237 at a second ratio.

  In conjunction with the increase in the arrangement pitch of the second longitudinal grooves 27 from the second region 237 toward the first region 238, the block portion from the second region 237 toward the first region 238 The area of 29 is also gradually increasing.

  As described above, in the present embodiment, the arrangement pitch of the longitudinal grooves 27 gradually increases from the second area 237 toward the first area 238. The occupancy ratio (second ratio) is configured to be larger than the occupancy ratio (first ratio) of the longitudinal groove portion 27 in the first region 238.

  Further, in the present embodiment, the ease of deformation of the absorbent core 420 gradually changes in the width direction from the center toward both sides. As a result, the deformation of the absorbent core 220 corresponding to the area from the groin to the swelling of the buttocks becomes gentle, and the fit is further improved.

Further, in the present embodiment, in the rear core portion 23, the area of each block portion 292 in the second region 237 is the same as that of each block portion 291 except for the block portion 291 having the boundary portion 23a of the pair of first regions 238. It is smaller than the area.
In other words, since the lateral groove portion 28 is provided such that the dimensions in the longitudinal direction of the block portion 292 and the block portion 291 are the same, the dimension in the width direction of the block portion 292 is the same as the width direction of the block portion 291 It is smaller than the size.

Thus, the area of the block portion 292 disposed in the second region 237 positioned at the central portion in the width direction is reduced, in other words, by shortening the dimension in the width direction of the block portion 292 The longitudinal groove portions 27 located between the adjacent block portions 292 are likely to be deformation starting points, and deformation is less likely to occur in the block portions 292.
Therefore, when the napkin 1 is attached, the napkin 1 is likely to be deformed into an ideal shape along the groin.

  As mentioned above, although each embodiment of the present invention was described, the present invention is not limited only to the above-mentioned embodiment, and it is needless to say that various change can be added in the range which does not deviate from the gist of the present invention.

For example, in the absorbent core of each embodiment described above, the absorbent core may have only the longitudinal groove without providing the lateral groove.
Moreover, the absorbent core of each of the above-mentioned embodiments had a flat planar shape in which the intermediate core portion 22 is narrower than the front core portion 21 and the rear core portion 23. On the other hand, it may be a flat, non-bindered absorbent core in which the width dimension does not change in the longitudinal direction of the absorbent core.

Further, in the first embodiment, the width of the longitudinal groove 27 and the arrangement pitch of the longitudinal grooves 27 are the same in the front core portion 21 and the rear core portion 23, while the second to fifth embodiments are implemented. In the embodiment, the width of the longitudinal grooves 27 and the arrangement pitch of the longitudinal grooves 27 are different between the front core portion 21 and the rear core portion 23.
In the second to fifth embodiments, the longitudinal groove portions 27 arranged in the front core portion 21 may be arranged with the same width and arrangement pitch as the rear core portion 23.

  Moreover, in the back core part of the absorptive core of each above-mentioned embodiment, although the case where the basis weight of a block part and the bottom part of a groove part differs was mentioned as an example and demonstrated, it is not limited to this, for example The basis weight of the bottom of the groove may be equal. The thickness of at least the bottom of the groove may be thinner than the thickness of the block, whereby the region in which the grooves are arranged is more likely to be deformed than the region in which the block is located.

  Moreover, in the above-mentioned embodiment, although the example which manufactures the absorptive core which has an uneven structure in a back structure surface was raised using the fiber laying apparatus, it is not limited to this. For example, a groove may be formed by partially pressing on one side of an absorbent core having a substantially flat surface having a substantially uniform thickness in the plane, and an absorbent core having a concavo-convex structure may be manufactured.

  Moreover, in the above each embodiment, although the example of the sanitary napkin was shown as an absorbent article, it is not limited to this. The absorbent article of the present invention may be, for example, an incontinence pad, a cage sheet, a disposable diaper or the like.

1 ... Napkins (napkins, absorbent articles)
20, 120, 220, 320, 420 ... Absorbent core 21 ... Forward core part 23 ... Rear core part 27 ... Longitudinal groove part 28 ... Horizontal groove part 29 ... Block part 53 ... Rear structural surface (structural surface)
237 ... second area 238 ... first area 239 ... third area 271 ... first longitudinal groove (longitudinal groove)
272: Second vertical groove (vertical groove)
291: Block part in the first area 292: Block part in the second area

Claims (7)

An absorbent core having a front core portion and a rear core portion located on both end sides in the longitudinal direction,
The aft core portion has a structural surface including a plurality of longitudinal grooves arranged in the width direction orthogonal to the longitudinal direction and extending in the longitudinal direction,
The structural surface is located on both sides in the width direction, and a pair of first regions occupied by the longitudinal grooves at a first ratio, and a longitudinal groove located on the center side in the width direction with respect to the first regions And a second region that occupies at a second ratio that is greater than the first ratio. An absorbent article according to claim 1, wherein
The pair of first regions are located on both sides in the width direction among the regions obtained by equally dividing the rear core portion into three in the width direction,
An absorbent article, wherein the second area is located at the center in the width direction among the three divided areas. The absorbent article according to claim 2, wherein
The number of longitudinal grooves provided in the second area is larger than the number of longitudinal grooves provided in the pair of first areas. Absorbent article. The absorbent article according to claim 2, wherein
The width of the vertical groove provided in the second area is wider than the width of the vertical groove provided in the pair of first areas. An absorbent article according to claim 1, wherein
The structural surface is located between the pair of first regions and the second region, and the pair of groove portions occupy at a third ratio which is larger than the first ratio and smaller than a second ratio. An absorbent article further comprising a third region. The absorbent article according to any one of claims 1 to 5, wherein
An arrayed pitch of the plurality of longitudinal grooves gradually increases from the second area toward the pair of first areas. The absorbent article according to any one of claims 1 to 6, wherein
The structural surface further includes: a plurality of lateral grooves arranged in the longitudinal direction and extending in the width direction; and a plurality of block portions partitioned by the plurality of longitudinal grooves and the plurality of lateral grooves.
The area of each block portion in the second region is smaller than the area of each block portion in the pair of first regions.

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