JP2020036735A - Absorbent article - Google Patents

Abstract

To provide an absorbent article capable of suppressing rubbing with the skin of a wearer.SOLUTION: The absorbent article comprises a liquid-permeable top sheet, a back sheet, an absorber having an absorbent core and disposed between the top sheet and the back sheet, and an adhesive part provided on the outer surface of the back sheet, and has a longitudinal direction corresponding to the front/back direction of the wearer and a lateral direction orthogonal to the longitudinal direction, and can be fixed to closing of the wearer. The absorbent core includes: a front core portion and a back core portion located at both ends in the longitudinal direction; an intermediate core portion located between the front core portion and the back core portion and formed to be narrower than the front core portion and the back core portion; and plural longitudinal grooves extending along the longitudinal direction and plural lateral grooves extending along the lateral direction, which are formed at least at the intermediate core portion. The surface sheet has plural projections projecting toward the outside in the thickness direction of the absorbent article.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an absorbent article such as a sanitary napkin used by being fixed to clothes.

  2. Description of the Related Art Conventionally, as a surface sheet for an absorbent article such as a sanitary napkin, a sheet in which embossing is performed on a surface that is in contact with a wearer's skin to form irregularities is known (Patent Documents 1 to 3). According to the surface sheet having the unevenness, the contact area with the wearer's skin can be reduced due to the presence of the unevenness.

JP 2009-512A JP 2011-15707 A JP-A-2005-186543

  By reducing the contact area between the wearer's skin and the topsheet, the frictional force acting between the wearer's skin and the absorbent article can also be reduced, leading to suppression of rubbing that occurs during wearing. However, there is a demand for an absorbent article that is less likely to be rubbed when worn and has a high feeling of wearing.

  An object of the present invention relates to an absorbent article that can suppress rubbing of a wearer's skin.

An absorbent article according to an embodiment of the present invention includes a liquid-permeable top sheet, a back sheet, an absorbent body having an absorbent core, disposed between the top sheet and the back sheet, and the back sheet. An adhesive portion provided on the outer surface of the wearer, having a vertical direction corresponding to the front-rear direction of the wearer and a horizontal direction orthogonal to the vertical direction, and configured to be capable of being fixed to the wearer's clothes. You.
The absorbent core,
A front core portion and a rear core portion located at both ends in the vertical direction,
An intermediate core portion located between the front core portion and the rear core portion, and having a width smaller than that of the front core portion and the rear core portion;
At least in the intermediate core portion, having a plurality of vertical grooves extending along the vertical direction and a plurality of horizontal grooves extending along the horizontal direction,
The top sheet is
The absorbent article has a plurality of protrusions projecting outward in the thickness direction.

  As described above, according to the absorbent article of the present invention, rubbing with the wearer's skin can be suppressed.

It is a top view showing the absorptive article concerning a 1st embodiment of the present invention. It is sectional drawing of the said absorbent article cut | disconnected by the II-II line of FIG. It is a top view which shows the absorbent core of the said absorbent article. It is a top view which shows the topsheet of the said absorbent article. It is sectional drawing of the said surface sheet cut | disconnected by the VV line of FIG. It is sectional drawing of the said surface sheet cut | disconnected by the VI-VI line of FIG. It is a top view showing the absorptive article concerning a 2nd embodiment of the present invention. It is a perspective view which shows the top sheet of the said absorbent article. It is a top view which shows the modification of the said absorbent article. It is a top view showing the absorptive article concerning a 3rd embodiment of the present invention. It is a figure which shows the measuring device used for the measurement of the compressive load of a horizontal direction in the Example of this invention, (A) is a top view, (B) is a side view.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First embodiment>
[Overall composition of napkin]
The absorbent article 1 according to the first embodiment of the present invention includes a main body M, a pair of wings W, and a pair of rear flaps F, as shown in FIG. The absorbent article 1 is configured as a sanitary napkin, and is hereinafter referred to as a napkin 1. The napkin 1 is configured to be able to be fixed to a wearer's clothes by an adhesive portion 15 described later.

  The main body M extends along the vertical direction X, and is fixed to the inner surface of the wearer's clothes when worn. The main body M has an absorber 11 described later, and has a function of absorbing a liquid material such as menstrual blood of a wearer (hereinafter, also referred to as “liquid”).

The wing portion W is configured to largely protrude outward in the lateral direction Y from the main body M.
The rear flap portion F is configured to bulge outward in the lateral direction Y at the rear portion of the main body M.
The napkin 1 may not have at least one of the wing W and the rear flap F. In addition to these configurations, the napkin 1 may include a pressing groove formed by pressing the main body M in the thickness direction Z from the surface sheet 12 described below.

  As shown in FIG. 2, the napkin 1 includes an absorber 11, a top sheet 12, a back sheet 13, and a pair of side sheets 14. In the main body M, the napkin 1 has a configuration in which the back sheet 13, the absorber 11, and the top sheet 12 are stacked in the thickness direction Z. These components are appropriately joined and integrated by, for example, joining with an adhesive or heat sealing, embossing with a compressed groove, or the like.

The absorber 11 extends in the longitudinal direction X and is disposed between the top sheet 12 and the back sheet 13. The absorber 11 absorbs the liquid from the surface on the side of the top sheet 12, diffuses the liquid inside, and holds the liquid.
The absorber 11 has an absorbent core 16 and a core wrap sheet 17.
The absorbent core 16 may be formed of, for example, a fiber aggregate formed of hydrophilic fibers such as pulp fibers, or may have a configuration in which the fiber aggregate holds a water-absorbing polymer. .
The core wrap sheet 17 has a function of covering the absorbent core 16 and maintaining the shape of the absorbent core 16, for example. The core wrap sheet 17 is formed of, for example, a thin soft paper such as a tissue paper or a liquid-permeable nonwoven fabric.
Details of the absorber 11 will be described later.

The top sheet 12 is configured as a liquid-permeable sheet material, and is disposed above the absorber 11 in the thickness direction Z. The upper surface of the topsheet 12, that is, the surface on the skin side of the wearer is defined as the outer surface 12a, and the lower surface, that is, the surface on the absorber 11 side is defined as the inner surface 12b. In addition, between the topsheet 12 and the absorber 11, the liquid permeability from the topsheet 12 to the absorber 11 is improved, and the liquid absorbed by the absorber 11 is prevented from returning to the topsheet 12. From the viewpoint, a second sheet (sub-layer sheet) may be arranged.
Details of the topsheet 12 will be described later.

The back sheet 13 is disposed below the absorber 11 in the thickness direction Z. The back sheet 13 is joined to the top sheet 12 and the side sheet 14 by an adhesive, a heat seal, or the like, for example, at the peripheral edge. The back sheet 13 may be joined to the absorber 11 with an adhesive or the like.
The back sheet 13 is formed of, for example, a sheet material having functions such as poor liquid permeability, water vapor permeability, and water repellency. As the sheet material, for example, a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used.

  The pair of side sheets 14 are arranged on the peripheral edge of the napkin 1 in the lateral direction Y, and face each other in the lateral direction Y with the top sheet 12 interposed therebetween. The side sheet 14 is joined to the top sheet 12 by an adhesive or the like inside the lateral direction Y. In the napkin 1 of FIG. 2, the side sheet 14 is not joined to the top sheet 12 at the laterally inner end, and is a free end. The inner end in the lateral direction Y of the side sheet 14 is not limited to the example of FIG. 2, and may be fixed by being folded outward. Alternatively, an elastic member that can expand and contract in the vertical direction X is attached to the end, and a three-dimensional gather that rises from the top sheet 12 side when worn may be formed. As the material of the side sheet 14, a sheet material having a lower hydrophilicity than the surface sheet 12 is preferable, and specifically, a nonwoven fabric, a film material, and a sheet having a laminate structure of the nonwoven fabric and the film material, which are less hydrophilic than the surface sheet Is mentioned.

The adhesive portion 15 is provided on the outer surface of the back sheet 13 and has a function as a slip stopper for fixing the napkin 1 to clothing.
The adhesive portion 15 is formed, for example, by applying an adhesive to the back sheet 13 in a predetermined pattern. As the pressure-sensitive adhesive used for the pressure-sensitive adhesive portion 15, a hot-melt pressure-sensitive adhesive such as a rubber-based, olefin-based, or ethylene vinyl acetate (EVA) -based adhesive is preferably used.
In the present embodiment, the adhesive section 15 is provided on the back sheet 13 of the main body M and the wing section W. Further, the adhesive portion 15 may be provided on the back sheet 13 of the rear flap portion F.

[Configuration of absorbent core]
(Planar shape of absorbent core)
As shown in FIG. 3, the absorbent core 16 has a front core section 20, an intermediate core section 21, and a rear core section 22. The front core section 20, the intermediate core section 21, and the rear core section 22 are arranged along the vertical direction X. That is, the front core section 20 and the rear core section 22 are located at both ends in the vertical direction X, and the intermediate core section 21 is located between the front core section 20 and the rear core section 22. The intermediate core portion 21 is a region facing the excretion portion of the wearer, and the front core portion 20 and the rear core portion 22 are portions facing the front and rear of the excretion portion of the wearer, respectively. The absorbent core 16 has a symmetrical planar shape in the horizontal direction Y.

The intermediate core portion 21 is configured to be narrower than the front core portion 20 and the rear core portion 22, and has a shape constricted from the left and right. The intermediate core section 21 has a width dimension D2 smaller than the width dimension D1 of the front core section 20 and the width dimension D3 of the rear core section 22.
The width dimension D2 of the intermediate core portion 21 refers to the minimum width dimension in the horizontal direction Y. The width dimension D1 of the front core section 20 and the width dimension D3 of the rear core section 22 refer to the maximum width dimension in the lateral direction Y.
Since the absorbent core 16 has the narrow intermediate core portion 21, when both legs of the wearer are closed and the crotch width is reduced, external force from the lateral direction Y applied to the intermediate core portion 21 is reduced. Can be.

The width dimension D1 of the front core section 20 and the width dimension D3 of the rear core section 22 may be the same or different, and have substantially the same size in the example shown in FIG. Further, the length dimension of the front core portion 20 and the rear core portion 22 in the longitudinal direction X may be the same or different. For example, the rear core portion 22 is configured to be longer.
In addition, “the width is constant” in a certain region means that when the minimum width in the horizontal direction Y of the region is 100%, the difference in the width in the region is within 20% or less. .

  In the example shown in FIG. 3, the intermediate core portion 21 includes a narrow portion 21a having a constant width dimension D2 along the longitudinal direction X, and a tapered portion 21b located in front of and behind the narrow portion 21a. And The tapered portion 21b is a region whose width gradually increases toward the front core portion 20 and the rear core portion 22.

As shown in FIGS. 3 and 2, the intermediate core portion 21 includes a high basis weight portion 23 formed in the center in the lateral direction Y, a low basis weight portion 24 formed around the high basis weight portion 23, have. In FIG. 3, the high basis weight portions 23 are indicated by dots. The high basis weight portion 23 extends in the vertical direction X, and has, for example, a curved shape whose front and rear ends are convex toward the vertical direction X.
The high basis weight portion 23 has a higher basis weight than the low basis weight portion 24 and is thicker in the thickness direction Z. In the example shown in FIG. 2, the high basis weight portion 23 protrudes from the low basis weight portion 24 toward the top sheet 12.
The provision of the high basis weight portion 23 in the intermediate core portion 21 can improve the fit and absorbability of the intermediate core portion 21 to the excretory portion.

(Configuration of vertical groove and horizontal groove)
As shown in FIG. 3, the absorbent core 16 has a plurality of vertical grooves 25 extending along the vertical direction X and a plurality of horizontal grooves 26 extending along the horizontal direction Y. The absorbent core 16 is divided into a plurality of blocks 27 by a plurality of vertical grooves 25 and a plurality of horizontal grooves 26.
It is sufficient that at least a part of the vertical groove 25 extends in the vertical direction X, and a part of the vertical groove 25 may be curved. Similarly, at least a part of the lateral groove 26 may be extended in the lateral direction Y.

  The vertical groove portion 25 and the horizontal groove portion 26 have a lower basis weight than the block portion 27, and are configured by grooves formed from the upper surface of the block portion 27 downward in the thickness direction Z. That is, the vertical groove 25 and the horizontal groove 26 are regions having lower rigidity than the block 27. Thereby, when an external force is applied to the napkin 1, the absorbent core 16 is easily deformed by the vertical groove portion 25 and the horizontal groove portion 26, and is flexible against external force in any of the vertical direction X and the horizontal direction Y. It is composed of

  In the intermediate core part 21, the vertical groove part 25 and the horizontal groove part 26 are formed so as to divide between the high basis weight part 23 and the low basis weight part 24 and the inside of the high basis weight part 23 and the low basis weight part 24, respectively. I have. That is, the high basis weight portion 23 and the low basis weight portion 24 are each divided into a plurality of block portions 27.

The operation and effect of the vertical groove 25 and the horizontal groove 26 during wearing of the napkin 1 will be specifically described.
For example, when walking, one of the left and right legs goes forward, and the other leg extends backward. At this time, the front half of the absorbent core 16 is tilted toward the other leg by the leg that has come forward, and slightly turns around the vertical direction X. On the other hand, the rear half of the absorbent core 16 is tilted toward the front leg by the leg extending rearward, and slightly turns around the vertical direction X in the direction opposite to the front half. That is, at the time of walking, the absorbent core 16 repeats torsional deformation about the longitudinal direction X as an axis.
Since the absorbent core 16 is configured flexibly in both the vertical direction X and the horizontal direction Y, it is possible to prevent the torsional deformation due to the motion of the wearer from being hindered. Therefore, the ability of the absorbent core 16 to follow the movement of the wearer can be improved.

  Further, when an external force directed inward in the horizontal direction Y is applied to the intermediate core portion 21, the low-rigidity vertical groove portion 25 is easily compressed in the horizontal direction Y which is the groove width direction. The block portions 27 adjacent to each other are deformed so as to come into contact with each other and be crushed. That is, in the intermediate core portion 21, the flexibility in the lateral direction Y to which an external force is easily applied is also enhanced.

  Further, as shown in FIG. 2, in the napkin 1, the core wrap sheet 17 extends to the outside in the lateral direction Y from the side edge 21as of the narrow portion 21a of the absorbent core 16. For this reason, when a strong external force directed inward in the lateral direction Y is applied to the intermediate core portion 21, the core wrap sheet 17 acts as a cushioning material, so that deformation such that the intermediate core portion 21 is broken can be suppressed. . When the side sheet 14 as shown in FIG. 2 is provided, the force transmitted to the intermediate core 21 is softened by the above-described buffering action, so that the free end of the inner end of the side sheet 14 is It is easy to stand up to the side, which is effective for preventing leakage of excrement.

[Configuration of topsheet]
As shown in FIGS. 2 and 4, the topsheet 12 has a plurality of protrusions 30 protruding outward in the thickness direction Z of the napkin 1. Each protrusion 30 is formed between recesses 33 that are recessed downward in the thickness direction Z. The convex portion 30 is defined as a region protruding in the thickness direction Z between the concave portions 33.
The topsheet 12 may have a plurality of protrusions 30 on the absorbent core 16, and may have a region where the protrusions 30 are not formed, such as the periphery of the napkin 1.

(Structure of convex part)
As shown in FIG. 4, the protrusions 30 are divided into a plurality of high protrusions 31 and a plurality of low protrusions 32.
The high convex portion 31 is a convex portion 30 having a relatively high height in the thickness direction Z, and the low convex portion 32 is a convex portion 30 having a relatively low height in the thickness direction Z. The planar shape of the high convex portion 31 viewed from the thickness direction Z is, for example, a substantially elliptical shape. The planar shape of the low convex portion 32 viewed from the thickness direction Z is, for example, a substantially circular shape having a smaller area than the high convex portion 31. Each of the high convex portion 31 and the low convex portion 32 has a dome structure convex outward in the thickness direction Z, and the outer surface 12a is formed of a curved surface convex outward in the thickness direction Z.

  As shown in FIG. 5, the cross-sectional shape of the high convex portion 31 is a shape protruding outward in the thickness direction Z toward the top portion 34. The high protruding portion 31 is solid, for example, with fibers distributed inside. However, the inside of the high convex portion 31 may not be formed homogeneously, and the fiber density may be different. In addition, the high convex portion 31 may be configured to be hollow, with almost no fibers distributed on the inner surface 12b side.

  The top portion 34 is a portion where the height in the thickness direction Z is maximum in the high convex portion 31, and is located substantially at the center when the high convex portion 31 is viewed in plan from the thickness direction Z. The top portion 34 is formed, for example, in a point shape, but may be a region having a predetermined area. The dimension in the thickness direction Z from the top 34 to the inner surface 12b of the topsheet 12 is defined as the height Hb of the high protrusion 31.

  As shown in FIG. 6, the cross-sectional shape of the low convex portion 32 is a shape protruding outward in the thickness direction Z toward the top portion 35. The low protruding portion 32 is also formed, for example, solid, but may not be uniform or may be formed hollow.

  The top portion 35 is a portion where the height in the thickness direction Z is the maximum in the low convex portion 32, and is located substantially at the center when the low convex portion 32 is viewed in plan. The top 35 is formed in, for example, a point shape, but may be a region having a predetermined area. The dimension in the thickness direction Z from the top 35 to the inner surface 12b of the topsheet 12 is defined as the height Hs of the low protrusion 32. The height Hs of the low protrusion 32 is lower than the height Hb in the thickness direction Z of the high protrusion 31 shown in FIG.

  The recess 33 is a region in which the outer surface 12a is recessed below the thickness direction Z. The planar shape of the concave portion 33 viewed from the thickness direction Z is, for example, a linear shape that partitions the periphery of the convex portion 30, and may include a polygonal vertex surrounding each convex portion 30. Here, the vertex portion of the polygon is a portion that includes the vertex of the polygon and the side of the polygon extends from the vertex. The concave portion 33 shown in FIG. 4 has a shape including, for example, hexagonal and quadrangular vertices.

(Arrangement of convex parts)
As shown in FIG. 4, the protrusions 30 are arranged in a column along the vertical direction X.
The high convex portions 31 are arranged in a high convex column 31Lx along the vertical direction X. The low convex portions 32 are arranged in a low convex column 32Lx along the vertical direction X. The high convex column 31Lx and the low convex column 32Lx are alternately arranged in the horizontal direction Y.
In addition, the high convex portions 31 in the high convex portion column 31Lx and the low convex portions 32 of the adjacent low convex portion column 32Lx are arranged alternately. In other words, the adjacent convex portions 30 in the vertical column are displaced in the vertical direction X at an interval of half of the arrangement interval of the convex portions 30 in the vertical column, and are arranged in a staggered oblique lattice pattern. .

As shown in FIG. 4, the protrusions 30 are arranged in a row along the horizontal direction Y.
The high convex portions 31 are arranged in a row of high convex portions 31Ly along the horizontal direction Y. The low convex portions 32 are arranged in a low convex portion row 32Ly along the horizontal direction Y. The high convex portion rows 31Ly and the low convex portion rows 32Ly are alternately arranged in the vertical direction X.
In addition, the high convex portions 31 in the high convex portion rows 31Ly and the low convex portions 32 of the adjacent low convex portion rows 32Ly are alternately arranged. In other words, the protruding portions 30 in the adjacent rows are displaced in the horizontal direction Y at an interval of half of the arrangement interval of the protruding portions 30 in the row, and are arranged in a staggered oblique lattice pattern. .

  Note that the arrangement pattern of the protrusions 30 is not limited to the above, and may be a rectangular lattice arrangement in which the positions of the protrusions 30 are aligned in adjacent columns and rows, or may be another arrangement.

[Function and effect of napkin (absorbent article)]
As described above, in the napkin (absorbent article) 1 having the above configuration, the intermediate core portion 21 facing the excretion portion of the wearer is configured to be narrower than the front core portion 20 and the rear core portion 22. Thereby, the influence of the external force directed inward in the lateral direction Y from the wearer's thigh can be reduced.
In addition, since the absorbent core 16 has the plurality of vertical grooves 25 and the horizontal grooves 26, the flexibility of the absorbent core 16 can be increased, and the absorbent core 16 is easily deformed even when an external force is applied. Become. Accordingly, the napkin 1 is configured to be easily torsionally deformed following a motion such as walking, and is also configured to be flexible against an external force directed inward in the lateral direction Y from the wearer.

Here, the frictional force F acting between the napkin 1 and the wearer's skin is represented by the following equation (1).
F = μ × N (1)
μ indicates a coefficient of friction, and is a value mainly based on the surface state of the napkin 1. N indicates a normal force, and is a value based on the contact load acting between the skin and the napkin 1.
In the present invention, the contact load acting between the wearer's skin and the napkin 1 is reduced by the narrow intermediate core portion 21, and the value of the drag N acting on the excretory part and the groin of the wearer is reduced. can do.
Furthermore, in the present invention, the flexibility and operation followability of the absorbent core 16 can be improved by the vertical grooves 25 and the horizontal grooves 26, so that the wearer's skin is less likely to be pressed. Thus, the value of the drag N acting on the excretory part and the groin part of the wearer can be reduced.
In addition, in the napkin 1, the topsheet 12 has a plurality of projections 30. Thereby, the contact area between the skin of the wearer and the topsheet 12 can be reduced, and the friction coefficient μ can be reduced.
As a result, in the napkin 1, the value of the frictional force F acting between the napkin 1 and the wearer's skin can be reduced, and rubbing of the wearer's excretory part and groin by the napkin 1 can be suppressed.

The plurality of protrusions 30 are divided into a plurality of high protrusions 31 and a plurality of low protrusions 32 whose height in the thickness direction Z is lower than each of the plurality of high protrusions 31.
By providing the high convex portion 31 and the low convex portion 32, the arrangement interval of the high convex portion 31 which is easily in contact with the wearer's skin can be widened. Thereby, the contact area between the topsheet 12 and the skin can be further reduced, and the friction coefficient μ and the frictional force F can be reduced. Therefore, rubbing of the wearer's skin by the napkin 1 can be more effectively suppressed.

  In the napkin 1, as shown in FIG. 2, the plurality of protrusions 30 are arranged outside the side edge 21 as of the narrow portion 21 a of the absorbent core 16. For this reason, the force applied to the lateral center of the absorbent core 16 can be buffered against the force applied by the wearer's thigh from the lateral outside of the narrow portion 21a. In particular, if a non-adhesion portion between the topsheet 12 and the absorber 11 is provided in the vicinity of the side edge portion 21as, the buffering action is further enhanced.

The plurality of convex portions 30 are arranged in a row along the horizontal direction Y.
Accordingly, the contacts of the protrusions 30 are arranged at intervals in the horizontal direction Y, and the contact area between the topsheet 12 and the skin can be reliably reduced. Therefore, rubbing can be effectively suppressed.
Further, the plurality of convex portions 30 are arranged in a vertical line along the vertical direction X.
In this manner, similarly, the contact area between the topsheet 12 and the skin can be reliably reduced, and rubbing can be effectively suppressed.

  In particular, in the napkin 1, the high convex portion rows 31Ly and the low convex portion rows 32Ly are alternately arranged in the vertical direction X, so that when the wearer moves vigorously, the skin moves in the vertical direction X. On the other hand, the convex portions are deformed and easily follow the movement of the skin, the coefficient of friction with the skin in the vertical direction X is reduced, and rubbing can be more effectively suppressed.

  Further, in the napkin 1, the high convex portion columns 31Lx and the low convex portion columns 32Lx are alternately arranged in the horizontal direction Y. Therefore, when the wearer moves vigorously, the movement of the skin in the horizontal direction Y is performed. On the other hand, the convex portions are deformed to easily follow the movement of the skin, the coefficient of friction with the skin in the lateral direction Y is reduced, and rubbing can be more effectively suppressed.

  Further, in the napkin 1, the high convex portion 31 in the high convex portion column 31Lx and the low convex portion 32 of the low convex portion column 32Lx adjacent to the high convex portion 31Lx are alternately arranged in the vertical direction X. When the body moves, the convex portion is deformed by the movement of the skin in an oblique direction that is an intermediate direction with respect to both the vertical direction X and the horizontal direction Y, and the skin easily follows the movement of the skin. And the friction coefficient can be more effectively suppressed.

Further, the absorbent core 16 is divided into a plurality of block portions 27 by a plurality of vertical groove portions 25 and a plurality of horizontal groove portions 26, and the plurality of vertical groove portions 25 and the plurality of horizontal groove portions 26 are separated from the plurality of block portions 27. Also have a low basis weight.
Thereby, the rigidity of the vertical groove 25 and the horizontal groove 26 with respect to the block 27 is reduced, and the vertical groove 25 and the horizontal groove 26 can be easily deformed. Therefore, the flexibility of the absorbent core 16 can be further increased, and the value of the drag N acting between the wearer's skin and the napkin 1 can be further reduced.

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

(Width of each part of the absorbent core)
The width dimensions D1 and D3 of the front core section 20 and the rear core section 22 are preferably 60 mm or more and 100 mm or less, and more preferably 70 mm or more and 90 mm or less.
The width dimension D2 of the narrow portion 21a of the intermediate core portion 21 is preferably 40 mm or more and 75 mm or less, and more preferably 50 mm or more and 70 mm or less.

(Basis weight of absorbent core)
The basis weight of the low basis weight part 24 in the absorbent core 16 excluding the vertical groove part 25 and the horizontal groove part 26 is preferably 90 g / m ² or more and 350 g / m ² or less, more preferably 100 g / m ² or more and 300 g / m ^{2. 2} or less.
Further, the basis weight of the high basis weight portion 23 is preferably 250 g / m ² or more and 700 g / m ² or less, and more preferably 300 g / m ² or more and 650 g / m ² or less.

(Method of measuring the basis weight of the absorbent core)
The measurement target area of the absorbent core 16 is cut using a single-edged razor manufactured by Feather Co., Ltd. to obtain a small piece having a predetermined area. The weight of these small pieces is measured using an electronic balance (an electronic balance GR-300 manufactured by A & D, precision: 4 digits after the decimal point). The calculated weight is divided by the area of the small piece of each part to calculate the basis weight of the small piece. For each part, the average of the basis weights of the five small pieces is defined as the basis weight.

(Planar shape of high basis weight part)
As shown in FIG. 3, the high basis weight portion 23 extends in the vertical direction X over the entire length of the narrow portion 21a of the intermediate core portion 21. The front and rear ends of the high basis weight portion 23 are curved in an arc shape or an elliptical arc shape. The length of the high basis weight portion 23 in the vertical direction X does not need to match the length of the narrow portion 21a, and the shape of the tip may be various such as triangular, trapezoidal, rectangular with rounded corners, and the like. May be in the form of

(Thickness of intermediate core)
The thickness dimensions of the high basis weight portion 23 and the low basis weight portion 24 can be set in consideration of the basis weight.
The dimension of the high basis weight portion 23 in the thickness direction Z is, for example, 2 mm or more and 9 mm or less, and preferably 2.5 mm or more and 8 mm or less from the viewpoint of reducing the occurrence of discomfort.
The dimension in the thickness direction Z of the low basis weight portion 24 is, for example, 1.5 mm or more and 6 mm or less, preferably 2 mm or more and 5.5 mm or less from the viewpoint of reducing the occurrence of discomfort.

(Detailed configuration of the vertical groove in the intermediate core)
In the intermediate core portion 21, the vertical groove portion 25 is divided into a first vertical groove portion 25a located at the center in the horizontal direction Y and a second vertical groove portion 25b located on the lateral side of the first vertical groove portion 25a in the Y direction. . As described above, the second vertical groove portion 25b is formed so as to surround the periphery of the high basis weight portion 23, and is formed by a curve at the front and rear ends of the high basis weight portion 23.
The first vertical groove 25a can impart flexibility to the high-basis-weight portion 23 having high rigidity.
When the low basis weight portion 24 is deformed by an external force, the second vertical groove portion 25b cuts off the propagation of the deformation and prevents the high basis weight portion 23 from being deformed. Therefore, the fit of the napkin 1 to the excretory part is enhanced, and as a result, the napkin 1 and the excretory part can be prevented from rubbing. Moreover, the breakage of the high basis weight portion 23 can be prevented by positioning the second vertical groove portion 25b so as to partition the high basis weight portion 23.

(Detailed configuration of the lateral groove in the intermediate core)
The horizontal groove portions 26 are located at substantially equal intervals in the vertical direction X in the intermediate core portion 21 and are formed, for example, at the boundary between the narrow portion 21a and the tapered portion 21b. The boundary may be a region facing the vicinity of the front end and the rear end of the excretion part of the wearer in the absorbent core 16. For this reason, flexibility can be imparted to the area by the lateral groove portion 26, and the napkin 1 can be easily fitted to the body shape of the wearer at the front and rear end portions of the excretory portion and bend easily. Therefore, it can contribute to suppression of the rubbing between the napkin 1 and the wearer.

(Structure of vertical groove in front core and rear core)
In the front core portion 20 and the rear core portion 22, the vertical groove portion 25 includes a first vertical groove portion 25a extending to the center in the horizontal direction Y, and second vertical groove portions 25b located on both sides of the first vertical groove portion 25a in the horizontal direction Y. , And a third vertical groove portion 25c located on both sides in the horizontal direction Y of the second vertical groove portion 25b.
For example, the first vertical groove 25a extends over the entire length of the absorbent core 16 in the vertical direction X.
The second vertical groove portion 25b extends over the entire length of the rear core portion 22 and the front core portion 20 in the vertical direction X. The second vertical groove 25b is not continuous between the front core section 20, the rear core section 22, and the intermediate core section 21.
The third vertical groove portion 25 c extends over the entire length of the rear core portion 22 and the front core portion 20 in the vertical direction X.
The configuration of these vertical groove portions 25 is not limited, and may be formed in a part of each portion in the vertical direction X, and the groove width may not be constant.

(Structure of the lateral groove in the front core and the rear core)
The horizontal groove portions 26 are located at substantially equal intervals in the vertical direction X in the front core portion 20 and the rear core portion 22. However, the arrangement intervals of the lateral groove portions 26 are not limited to equal intervals, and may be different. Further, each lateral groove 26 is formed over the entire width of the absorbent core 16 in the lateral direction Y, but may be formed only in a part of the lateral direction Y. Further, the groove width of each lateral groove 26 may be the same or different.

(Arrangement interval of vertical and horizontal grooves)
The arrangement interval of the vertical grooves 25 is, for example, 5 mm or more and 25 mm or less, and more preferably 8 mm or more and 20 mm or less, from the viewpoint of giving the absorbent core 16 flexibility in the horizontal direction Y.
The arrangement interval of the horizontal groove portions 26 is, for example, 10 mm or more and 35 mm or less, and more preferably 15 mm or more and 30 mm or less, from the viewpoint of giving the absorbent core 16 flexibility in the vertical direction X.

(Groove width of vertical and horizontal grooves)
The groove width of the vertical groove 25 and the horizontal groove 26 is preferably 0.5 mm or more and 10 mm or less, more preferably 1 mm or more and 5 mm or less. The depth of the vertical groove 25 and the horizontal groove 26 is, for example, 0.5 mm or more and 10 mm or less.

(Additional explanation of vertical and horizontal grooves)
In addition to the above description, the configuration such as the shape and arrangement of the vertical groove 25 and the horizontal groove 26 is not limited to the configuration shown in FIGS.
The “low basis weight” of the vertical grooves 25 and the horizontal grooves 26 is a concept including a form in which the material of the absorbent core 16 is present and a form in which the material of the absorbent core 16 is not present. In the form in which the material of the absorbent core 16 is present in the vertical groove 25 and the horizontal groove 26, since the block portions 27 located on both sides thereof are connected via the vertical groove 25 and the horizontal groove 26, the absorbent core 16 is This is more preferable because the movement hardly causes twisting, destruction, or breakage.
Alternatively, the vertical groove portion 25 and the horizontal groove portion 26 are not in a low basis weight as compared with the block portion 27, and are formed in a groove shape by compressing the absorbent core 16 (the absorber 11) in the thickness direction Z. Is also good. Thereby, the vertical groove portion 25 and the horizontal groove portion 26 are configured to have higher rigidity than the block portion 27, and can be a starting point of the deformation of the absorbent core 16. That is, when an external force is applied to the napkin 1, the block portion 27 between the vertical groove portion 25 and the horizontal groove portion 26 is easily deformed, and as a result, the flexibility of the napkin 1 can be increased.

(Detailed configuration of the topsheet)
As shown in FIGS. 5 and 6, the protrusions 30 of the topsheet 12 include, for example, an upper non-heat-shrinkable fiber layer 12u and a lower heat-shrinkable fiber layer 12d. The topsheet 12 has a configuration in which the heat-shrinkable fiber layer 12d is thermally shrunk on the inner surface 12b side of the projection 30, and a configuration in which the non-heat-shrinkable fiber layer 12u is raised on the outer surface 12a side.
On the other hand, in the concave portion 33, these two fiber layers are compressed in the thickness direction Z. That is, the concave portion 33 has a configuration in which the fiber density is higher than that of the convex portion 30.
The high convex portion 31 and the low convex portion 32 can be formed by adjusting the pattern of the concave portion 33. Specifically, the high convex portion 31 can be formed in a region where the concave section 33 has a large area, and the low convex portion 32 can be formed in a region where the concave section 33 has a small area.
As described above, in the topsheet 12, the high convex portions 31 and the low convex portions 32 can be easily formed. Thereby, the topsheet 12 having a low coefficient of friction can be realized. Further, a fiber density gradient can be provided to the topsheet 12 such that the fiber density gradually increases from the tops 34 and 32t toward the recess 33. This allows the topsheet 12 to quickly draw in the liquid, thereby suppressing an increase in the friction coefficient of the topsheet 12 even after excretion of the liquid.

(Material of top sheet)
As the non-heat-shrinkable fiber layer 12u, for example, a web formed by a card method or a bulky nonwoven fabric is preferably used. The web formed by the card method is a fiber aggregate before being made into a nonwoven fabric. As a bulky nonwoven fabric, an air-through nonwoven fabric, an air-laid nonwoven fabric, an air-laid nonwoven fabric, from the viewpoint that it is possible to impart a desired density gradient to the topsheet 12 and it is possible to provide a good texture to the topsheet 12 Resin-bonded nonwoven fabrics are preferably used.
As the heat-shrinkable fiber layer 12d containing the heat-shrinkable fibers, a web formed by a card method or a non-woven fabric having heat-shrinkability can be used. Specifically, as the heat-shrinkable fiber of the constituent fibers of the heat-shrinkable fiber layer 12d, a heat-shrinkable fiber made of a thermoplastic polymer material is preferably used. Examples of such fibers include latently crimpable fibers. Latent crimpable fibers can be handled in the same manner as conventional nonwoven fabric fibers before they are heated, and have the property of developing and contracting a spiral crimp by heating at a predetermined temperature. Fiber. The latently crimpable fiber, which is a heat-shrinkable fiber, is composed of, for example, an eccentric core-sheath type or side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage rates. Examples thereof include those described in JP-A-9-296325 and Japanese Patent No. 2759331.

(Method of manufacturing topsheet)
First, a sheet material constituting the non-heat-shrinkable fiber layer 12u and a sheet material constituting the heat-shrinkable fiber layer 12d are laminated and compressed in a linear emboss pattern. Thus, a laminate including the non-heat-shrinkable fiber layer 12u and the heat-shrinkable fiber layer 12d is formed. At the same time or after this, heat is applied to the laminate to thermally shrink the heat-shrinkable fiber layer 12d in the in-plane direction, thereby producing the topsheet 12 having the above-described configuration.

(Coefficient of friction of the topsheet with the wearer's skin)
The coefficient of friction of the topsheet 12 with the wearer's skin is preferably 0.30 or less, more preferably 0.25 or less, from the viewpoint of suppressing the rubbing of the topsheet 12 with the wearer's skin as described above.
The coefficient of friction with the wearer's skin can be measured as follows.
The topsheet 12 is cut into a sample having a size of 50 mm (MD direction) × 50 mm (CD direction), and a weight with a hook (weight 211 g, length 63 mm × width 63 mm × thickness 7 mm) is prepared using a paper double-sided tape. Are bonded such that the inner surface 12b on the opposite side to the convex portion 30 of the second surface becomes the back surface. The sample to which the weight was adhered was allowed to stand on an acrylic plate so that the outer surface 12a on the side of the convex portion 30 was on the lower side, a wire was attached to the hook, and a tensile tester (for example, a tensile tester manufactured by Orientec) was attached via a pulley. Attach to a testing machine Tensilon RTC-1210A). The weight adhered to the sample is pulled at a pulling speed of 200 mm / min, and is slid horizontally on the acrylic plate. Using the average value of the recorded load of the chart as a frictional force, a friction coefficient is calculated from the weight of the sample to which the weight is adhered.

(Dimension of each convex part)
The height Hb of the high convex portion 31 (see FIG. 5) is preferably 1.0 mm or more from the viewpoint of enhancing the good feel of the topsheet 12 and enhancing the density gradient of the fibers to enhance the liquid draw-in property. More preferably, it is 1.5 mm or more, and preferably 7.0 mm or less, further preferably 5.0 mm or less, more specifically, 1.0 mm or more and 7.0 mm or less, and more preferably 1.5 mm or more and 5 mm or less. 0.0 mm or less is more preferable.
The height Hs of the low protrusions 32 (see FIG. 6) is preferably 0.4 mm or more from the viewpoint of enhancing the good feel of the surface sheet 12 and enhancing the density gradient of the fibers to enhance the liquid draw-in property. , More preferably 0.8 mm or more, and preferably 4.5 mm or less, more preferably 2.5 mm or less, more specifically, preferably 0.4 mm or more and 4.5 mm or less, and more preferably 0.8 mm or more. More preferably, it is 2.5 mm or less.

  In addition, the height H of the protrusion 30, specifically, the height Hb of the high protrusion 31 and the height Hs of the low protrusion 32 are determined by the thickness of the side edge 21 as in the narrow portion 21 a of the absorbent core 16. It is preferably smaller than. In the napkin 1, since the topsheet 12 extends beyond the side edge 21as in the narrow portion 21a in a plan view, the height of the projection 30 is smaller than the thickness of the side edge 21as in the portion. The legs of the wearer, particularly the thighs, can easily fit into the intermediate core 21.

(Arrangement of each convex part)
The arrangement interval of the protrusions 30 in the vertical direction X is preferably 0.5 mm or more, more preferably 1 mm or more, from the viewpoint of enhancing the liquid pull-in and diffusion properties of the topsheet 12 and maintaining a good visual impression and feel. 0.0 mm or more, and preferably 5.0 mm or less, more preferably 4.0 mm or less, more specifically, preferably 0.5 mm or more and 5.0 mm or less, and more preferably 1.0 mm or more and 4.0 mm or less. It is even more preferred.
The arrangement interval of the protrusions 30 in the lateral direction Y is preferably 0.5 mm or more, more preferably 1 mm or more, from the viewpoint of enhancing the liquid pull-in and diffusion properties of the topsheet 12 and keeping the appearance impression and feel good. 0.0 mm or more, and preferably 5.0 mm or less, more preferably 4.0 mm or less, more specifically, preferably 0.5 mm or more and 5.0 mm or less, and more preferably 1.0 mm or more and 4.0 mm or less. It is even more preferred.

<Second embodiment>
[Overall composition of napkin]
As shown in FIGS. 7 and 8, the absorbent article (napkin 1A) of the second embodiment of the present invention may have a topsheet 12A having a configuration different from that of the topsheet 12 of the first embodiment. .
That is, the napkin 1A includes the top sheet 12A, and the back sheet 13, the absorber 11, the side sheet 14, and the adhesive portion 15 having the same configuration as in the first embodiment. In the napkin 1A, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The topsheet 12A of the napkin 1A has a plurality of projections 30A protruding outward in the thickness direction Z and extending in a direction perpendicular to the thickness direction Z.
Hereinafter, the extending direction of the protrusion 30A is referred to as “longitudinal direction x”, and the arrangement direction of the protrusions 30A orthogonal to the longitudinal direction x is referred to as “width direction y”. In the topsheet 12, a direction orthogonal to the longitudinal direction x and the width direction y is referred to as a "thickness direction z".
In the example shown in FIG. 7, in the topsheet 12A, the longitudinal direction x of the protrusion 30A matches the longitudinal direction X of the napkin 1A, and the width direction y of the protrusion 30A matches the lateral direction Y of the napkin 1A.

[Configuration of topsheet]
As shown in FIG. 8, the topsheet 12 has a configuration in which a plurality of convex portions 30A extending along the longitudinal direction x are arranged in the width direction y with the concave portion 33A interposed therebetween. The outer surface 12Aa of the convex portion 30A is formed by a curved surface that is convexly outward in the Z-axis direction.

  The cross-sectional shape of the protrusion 30 shown in FIG. 8 is a shape protruding in the thickness direction z (outward in the thickness direction Z) of the topsheet 12A. The protrusion 30 is solid in FIG. 8, but may have a fiber density distribution, or may have a low fiber density on the inner surface 12 </ b> Ab side and may be formed substantially hollow.

  The top portion 34A is a portion where the height in the thickness direction z is the largest in the protrusion 30A, and is located substantially at the center in the width direction y when the protrusion 30 is viewed in plan from the thickness direction z. The top portion 34A is configured, for example, in a linear shape extending in the longitudinal direction x, but is not limited thereto, and may be configured in a band shape extending in the longitudinal direction x.

  The concave portions 33A are arranged alternately with the convex portions 30A in the width direction y, and are configured in a band shape extending in the longitudinal direction x. The recess 33A may be, for example, processed by compression and have a higher fiber density than the protrusion 30A.

  With the topsheet 12A, the region in contact with the wearer's skin can be made linear or band-like, and the contact area between the napkin 1 and the wearer can be reduced. Therefore, the friction coefficient of the topsheet 12A can be reduced, the contact load between the napkin 1 and the wearer can be reduced, and the rubbing between the napkin 1 and the wearer can be effectively prevented. Furthermore, since a uniform and smooth feel can be given to the wearer, the wearing feeling can be improved.

  In addition, as shown in FIG. 7, by arranging the topsheet 12A such that the longitudinal direction x of the protrusion 30A coincides with the longitudinal direction X of the napkin 1A, an external force is applied by the wearer in the lateral direction Y. In this case, the topsheet 12 can also be flexibly deformed in the lateral direction Y. Therefore, the contact load applied to the wearer can be further reduced.

[Other configurations of napkins]
As shown in FIG. 9, the topsheet 12A may be arranged such that the longitudinal direction x of the protrusion 30A matches the lateral direction Y of the napkin 1A (absorber 11). Thereby, the deformation of the napkin 1 along the longitudinal direction X can be made easier, and the fitting property to the curved shape of the wearer's body and the followability to the movement can be improved.

<Third embodiment>
[Other Configurations of Absorbent Core]
As shown in FIG. 10, the absorbent article (napkin 1B) of the third embodiment of the present invention has an absorbent core 16B having a different configuration from the absorbent core 16 of the first embodiment.
That is, the napkin 1B includes the absorber 11B having the absorbent core 16B, and the top sheet 12, the back sheet 13, the side sheet 14, and the adhesive section 15 having the same configuration as in the first embodiment. In the napkin 1B, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The intermediate core portion 21B of the absorbent core 16B may have a constricted shape formed by a curve.
In the intermediate core portion 21B, the entire outer edge in the lateral direction Y may be configured with a curved line, or at least a part of the outer edge such as the front and rear ends may be configured with a curved line. The shape of the outer edge in the lateral direction Y of the intermediate core portion 21 may be symmetrical in the front-rear direction as shown in FIG. 10 or may be asymmetrical in the front-rear direction.

  This makes it easier for the intermediate core 21 to conform to the shape of the wearer's rounded thigh. Therefore, the contact load from the napkin 1 to the wearer's thigh can be further reduced, and the rubbing between the napkin 1 and the wearer's skin can be further suppressed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

  In the above embodiment, the example of the sanitary napkin is shown as the absorbent article, but the absorbent article is not limited to this. The absorbent article of the present invention may be, for example, a urine-absorbing pad or a vaginal sheet that is used by being fixed to clothing.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

[Preparation of absorbent article for evaluation]
(Example 1)
As an absorbent article of Example 1, a sanitary napkin (napkin) having a configuration shown in FIGS. 1 to 3 was produced.
First, the topsheet shown in FIGS. 4 to 6 was prepared. Specifically, an upper layer made of a non-thermocompressible fiber and a lower layer made of a heat-shrinkable fiber were laminated, and this laminate was subjected to a compression process in the thickness direction using an emboss pattern including a polygonal vertex. As the non-thermocompressible fiber, a core-sheath type composite fiber having polyethylene terephthalate as a core component and polyethylene as a sheath component was used. Subsequently, the laminate was exposed to hot air at 110 ° C. ± 10 ° C. for 5 to 10 seconds to shrink the lower heat-shrinkable fibers in the plane direction. As a result, a top sheet having an upper layer protruding in a convex shape and having a high convex portion and a low convex portion in a multi-dimensional dome structure was produced.
The closest interval between two adjacent concave portions in the longitudinal direction of the topsheet after the heat shrinkage was 1.1 mm. The height Hb of the high convex portion was 2.3 mm, and the height Hs of the low convex portion was 1.5 mm.
Subsequently, the absorbent core was wound around a core wrap sheet to produce an absorber. As shown in FIG. 3, the absorbent core had a narrow intermediate core portion, and a block structure was formed by vertical and horizontal grooves. As shown in Table 1, the width dimensions of the front core portion and the rear core portion of the absorbent core were both 67 mm, and the width size of the intermediate core portion was 57 mm. The thickness and basis weight of the absorbent core were 3.5 mm and 200 g / m2 except for the high basis weight part in the intermediate core part, and were 5.5 mm and 400 g / m2 for the high basis weight part. The depth of the vertical groove and the horizontal groove was 4 mm in the high basis weight portion.
The napkin of Example 1 was obtained by disposing this absorber between the top sheet and the back sheet made of a resin film made of polyethylene. The topsheet was fixed on the absorber by applying an adhesive on the absorber in a spiral pattern. At this time, the topsheet was arranged so that the row of high protrusions in the direction along the major axis of the high protrusions coincided with the longitudinal direction of the absorber. The topsheet and the core wrap sheet were joined with a hot melt adhesive, but they were not adhered to each other at the narrow side wall of the intermediate core.

(Example 2)
A sanitary napkin having the same configuration as that of Example 1 was produced except that the width dimension of the intermediate core portion of the absorbent core was changed to the dimension shown in Table 1. That is, as shown in Table 1, the front core portion, the rear core portion, and the intermediate core portion of the absorbent core of Example 2 had widths of 67 mm, 67 mm, and 62 mm, respectively.

(Example 3)
Except that the width dimensions of the front core portion, the rear core portion, and the intermediate core portion of the absorbent core were changed to the dimensions shown in Table 1, and the thickness and basis weight of the absorbent core were changed, the same configuration as in Example 1 was used. A sanitary napkin was prepared. That is, as shown in Table 1, the front core portion, the rear core portion, and the intermediate core portion of the absorbent core of Example 2 had widths of 80 mm, 80 mm, and 60 mm, respectively. The thickness and basis weight of the absorbent core part were 4.0 mm and 220 g / m ² except for the high basis weight part in the intermediate core part, and the high basis weight part was 7.0 mm and 550 g / m ² .

(Comparative Example 1)
As a sample of Comparative Example 1, a sanitary napkin having the same configuration as that of Example 1 was prepared except that the width of the intermediate core of the absorbent core was the same as the width of the front core and the rear core. As shown in Table 1, the width dimension of the front core portion, the rear core portion, and the intermediate core portion of the absorbent core of Comparative Example 1 was 67 mm.

(Reference example)
As a sample of the reference example, a sanitary napkin having the same configuration as that of the example 3 except that the convex portion of the topsheet was made to have a uniform height.
The configuration of the topsheet was different from Examples 1 to 3 and Comparative Example 1 in that the fiber sheet material was subjected to compression processing in the thickness direction with a linear emboss pattern to form concave portions and convex portions. Specifically, the concave portion has linear embosses extending in one direction and linear embosses extending in the other direction intersecting with the linear embosses, which are arranged at equal intervals. The convex portion had a rectangular planar shape surrounded by these concave portions.

(Comparative Example 2)
As a sample of Comparative Example 2, a commercially available sanitary napkin (manufactured by Unicharm Corporation, trade name “Body Fit”, manufactured in 2018) was prepared.
The napkin of Comparative Example 2 was provided with a surface sheet having no irregularities and an absorbent core having no block structure but having a constriction.
As shown in Table 1, the topsheet had a plurality of openings.
The width dimension of the absorbent core was 75 mm in the front core portion and the rear core portion, and 57 mm in the intermediate core portion.
The absorbent core did not have vertical and horizontal grooves, and was not divided into blocks.

[Evaluation test]
For the absorbent articles of Examples 1 to 3, Comparative Examples 1 and 2, and Reference Example, the coefficient of friction between the topsheet and the skin, the compressive load in the lateral (width) direction, and the absorbent articles during walking were determined by the following methods. And the groin were measured for shear stress.
The coefficient of friction between the topsheet and the skin corresponds to μ in the above equation (1), and evaluates the ease of rubbing between the topsheet and the skin.
The lateral compressive load evaluates the flexibility of the absorbent article and the magnitude of the contact load applied to the skin with respect to the lateral compression from the wearer's thigh.
The shear stress between the absorbent article and the groin during the walking operation is to evaluate the easiness of rubbing with the groin during walking.

(Method of measuring coefficient of friction with skin)
First, in each of the topsheets of Examples 1 to 3, Comparative Examples 1 and 2, and Reference Example, the coefficient of friction between the topsheet and skin corresponding to μ in the above formula (1) was measured by the following method.
Cut out to a size of 50 mm (MD direction) x 50 mm (CD direction), use a double-sided tape made of paper for a weight with a hook (weight 211 g, length 63 mm x width 63 mm x thickness 7 mm), and oppose the convex portion 30 of the sample. Adhesion was performed so that the side surface was the back surface. The sample to which the weight was adhered was placed on an acrylic plate so that the surface on the side of the convex portion 30 was on the lower side, a wire was attached to the hook, and a tensile tester Tensilon RTC-1210A manufactured by Orientec was connected via a pulley. Attached. The weight adhered to the sample was pulled at a pulling speed of 200 mm / min, and was slid horizontally on the acrylic plate. The friction coefficient was calculated from the weight of the sample to which the weight was adhered, using the average value of the recorded load of the chart as a frictional force.
Table 1 shows the measurement results.

(Results of measurement of coefficient of friction with skin)
As shown in Table 1, each of Examples 1 to 3 and Comparative Example 1 had a friction coefficient of 0.24.
On the other hand, the friction coefficient of the reference example was 0.36, and the friction coefficient of the comparative example 2 was 0.33.
In other words, it was confirmed that the friction coefficient of the topsheet could be sufficiently reduced by the topsheet having the convex portions. Further, it was confirmed that the surface sheets of Examples 1 to 3 having the high convex portions and the low convex portions can further reduce the friction coefficient.

(Measurement method of lateral compressive load)
Referring to the above formula (1), the frictional force that causes the wearer to rub depends not only on the friction coefficient μ but also on the magnitude of the contact load (drag N) exerted on the wearer by the absorbent article.
Therefore, in order to evaluate the contact load exerted on the wearer by each of the napkins of Examples 1 to 3, Comparative Examples 1 and 2, and the reference example, the compressive load in the lateral (width) direction of each napkin (hereinafter referred to as the width compressive load). ) Was measured. The compressive load corresponds to a contact load exerted on the wearer by the absorbent article when a lateral external force is applied to the absorbent article from the thigh of the wearer during wearing.
As shown in FIG. 11, TENSILON RTC-1210S (measurement device T) and a jig J were used as measurement devices. The jig J has a pair of arcs J11 and J12 for applying a width compressive load to the sample S, and a pulley J2 for pulling a string J3 attached to the arc J11.
In the sample S, tissue paper was stuck on the entire surface of the adhesive portion of the back sheet of the napkin body, and the wing portion and the rear flap portion were placed between the arcs J11 and J12 in a state of being folded back toward the back sheet. At this time, the width of the sample S was adjusted to be the same as the width of the core wrap sheet.
As shown in FIG. 11A, the sample S has an intermediate portion (the excretion portion facing region) at the same horizontal position as the apex of the pair of arcs J11 and J12 of the jig J, and is in contact with the arc J12 on the pulley J2 side. And placed below the fixed string J4. At this time, the distance between the left and right arcs J11 and J12 was adjusted to 100 mm.
At the time of measurement, the string J3 attached to the arc J11 is pulled by the measuring device T and the pulley J2 to compress the sample S until the width becomes 30 mm, and the load at the time when the sample S is compressed to the width of 50 mm is defined as the width compression load. It was measured. The measurement conditions were as follows: the tensile speed was 50 mm / min, and the height of the fixing cord J4 from the mounting surface of the sample S was 22 mm.
Table 1 shows the measurement results.

(Measurement result of lateral compressive load)
As shown in Table 1, the compression load of Example 1 was 39 cN, the compression load of Example 2 was 44 cN, and the compression load of Example 3 was 90 cN.
On the other hand, the compressive load of Comparative Examples 1 and 2 was 142 cN, and the compressive load of Comparative Example 2 was 120 cN, which was larger than the value of the compressive load of each Example. The values were above.
From these results, in the napkins of Examples 1 to 3, the intermediate core portion is configured to be narrow, and the absorbent core has the vertical groove portion and the horizontal groove portion. It was confirmed that the flexibility was high.

歩行動作モデルの動作条件は、歩行速度100歩／分、脚左右開閉角0°（股間幅50mm）、脚前後開閉角−15〜15°、歩行時間60秒とした。 (Measurement method of shear stress between absorbent article and groin during walking movement)
Next, in order to directly evaluate the wearer's rubbing between the groin and the napkin during walking, a shearing stress between the absorbent article and the groin was measured using a walking movement model. Higher shear stress indicates that the absorbent article and the groin rub.
First, a measuring instrument (Touchence shock tip SP type) was attached to the inguinal region of the walking motion model. Then, the model was put on general underwear to which the napkins of Examples 1 to 3, Comparative Examples 1 and 2 and Reference Example were fixed, and shearing in the vertical direction X and the horizontal direction Y was performed by a measuring device during walking. The stress was measured, and the average value of the amplitude of each of the longitudinal X shear stress and the lateral Y shear stress from 30 seconds to 60 seconds after the start of walking was calculated. The obtained average values were applied to the calculation formula (2) to obtain the shear stress with the groin.

The operating conditions of the walking motion model were a walking speed of 100 steps / minute, a leg left / right opening angle of 0 ° (crotch width of 50 mm), a leg front / rear opening / closing angle of −15 to 15 °, and a walking time of 60 seconds.

歩行動作モデルの動作条件は、歩行速度100歩／分、脚左右開閉角0°（股間幅50mm）、脚前後開閉角−15〜15°、歩行時間60秒とした。 (Measurement method of shear stress of absorbent article and excretion part during walking motion)
Subsequently, in order to directly evaluate the rubbing between the excretion part and the napkin of the wearer during the walking motion, the shearing stress between the absorbent article and the excretion part was measured using a walking motion model. A higher shear stress indicates that the absorbent article and the excretory part are rubbed.
First, a measuring device (a small three-axis force sensor USL06-H5-50N manufactured by Tech Co., Ltd.) was attached to the excretion part of the walking motion model. Then, the model was worn with general underwear to which the napkins of Examples 1 to 3, Comparative Examples 1 and 2, and Reference Example were fixed, and shearing in the vertical direction X and the horizontal direction Y was performed by a measuring device while walking. The stress was measured, and the average value of the amplitude of each of the longitudinal X shear stress and the lateral Y shear stress from 30 seconds to 60 seconds after the start of walking was calculated. The obtained average values were applied to the calculation formula (3) to obtain the shear stress with the excretory part.

The operating conditions of the walking motion model were a walking speed of 100 steps / minute, a leg left / right opening angle of 0 ° (crotch width of 50 mm), a leg front / rear opening / closing angle of −15 to 15 °, and a walking time of 60 seconds.

(Measurement results of shear stress between absorbent article and groin / excretion area during walking movement)
As shown in Table 1, the shear stress with the groin in Examples 1, 2, and 3 was 0.84 N, 0.90 N, and 0.92 N, respectively.
On the other hand, the shear stress with the groin in Comparative Examples 1 and 2 and Reference Example were 1.08 N, 1.25 N, and 1.10 N, respectively.
Moreover, as shown in Table 1, the shear stress with the excretory part of Examples 1, 2, and 3 was 0.97 N, 1.13 N, and 1.32 N, respectively.
On the other hand, the shear stress with the excretory part of Comparative Examples 1 and 2 and the reference example were 1.69 N, 2.19 N and 1.89 N, respectively.
From these results, the napkins of Examples 1 to 3 were constructed such that the intermediate core portion was configured to be narrow, the absorbent core had a vertical groove and a horizontal groove, and the topsheet had a convex portion. It was confirmed that the rubbing with the wearer's skin in can be suppressed. In particular, the napkins of Examples 1 to 3 can suppress the rubbing between the groin and the excretory part, and are thus effective in relieving discomfort during menstruation.

1. Napkin (absorbent article)
DESCRIPTION OF SYMBOLS 11 ... Absorber 12 ... Top sheet 13 ... Back sheet 15 ... Adhesive part 16 ... Absorbent core 20 ... Front core part 21 ... Intermediate core part 22 ... Back core part 25 ... Vertical groove part 26 ... Horizontal groove part 30 ... Convex part

Claims (7)

A liquid-permeable top sheet, a back sheet, having an absorbent core, an absorber disposed between the top sheet and the back sheet, and an adhesive portion provided on an outer surface of the back sheet, An absorbent article comprising a vertical direction corresponding to the front-rear direction of the wearer and a horizontal direction orthogonal to the vertical direction, and configured to be able to be fixed to the clothes of the wearer,
The absorbent core comprises:
A front core portion and a rear core portion located at both ends in the longitudinal direction,
An intermediate core portion located between the front core portion and the rear core portion and having a width smaller than that of the front core portion and the rear core portion;
A plurality of vertical grooves extending along the vertical direction and a plurality of horizontal grooves extending along the horizontal direction, formed at least in the intermediate core portion,
The topsheet,
An absorbent article having a plurality of projections located on the absorbent core and projecting outward in the thickness direction of the absorbent article. The plurality of protrusions,
A plurality of high protrusions,
The absorbent article according to claim 1, wherein the absorbent article is divided into a plurality of low protrusions having a height in the thickness direction lower than each of the plurality of high protrusions. The plurality of high protrusions and the plurality of low protrusions are arranged in a row of high protrusions and a row of low protrusions along the horizontal direction, respectively.
The absorbent article according to claim 2, wherein the high convex portion rows and the low convex portion rows are alternately arranged in the vertical direction. 4. The plurality of high convex portions and the plurality of low convex portions are arranged in a row of high convex portions and low convex portions along the longitudinal direction, respectively. 5. Absorbent articles. The absorbent article according to any one of claims 1 to 4, wherein each of the plurality of protrusions extends in a direction orthogonal to the thickness direction. The absorbent article according to any one of claims 1 to 5, wherein the intermediate core has a constricted shape formed by a curve. The absorbent core is divided into a plurality of blocks by the plurality of vertical grooves and the plurality of horizontal grooves,
The absorbent article according to any one of claims 1 to 6, wherein the plurality of vertical grooves and the plurality of horizontal grooves have a lower basis weight than the plurality of blocks.

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