JP7118749B2 - absorbent article - Google Patents

Description

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

When a sanitary napkin is used, liquid tends to leak outside through a gap between the sanitary napkin and the wearer. For this reason, in order to improve fit to the wearer, an absorbent article such as a sanitary napkin is known to have a mid-high portion with a large thickness in the front-back direction central portion (see Patent Document 1). In the structure of the absorbent body described in Patent Document 1, the absorbent body is provided with a width between the mid-high portion and the rear portion so as to absorb the deformation of the buttocks due to the bedding when lying on one's back while sleeping. A region having a lower or no absorbent material basis weight than the other regions is provided so as to traverse the direction.

JP 2016-67823 A

When a region with a low basis weight or no region is provided across the width direction of such an absorbent body, the rigidity of the region with a low basis weight or no region is low, and the difference in rigidity between the area and the middle and high parts is particularly large. Inappropriate deformation such as twisting is likely to occur.
An object of the present invention is to provide an absorbent article that is less prone to inappropriate deformation.

The absorbent article of the present invention comprises an absorbent core.
The absorptive core has a front core portion and a rear core portion positioned at both ends in the front-rear direction, and an intermediate core portion positioned between the front core portion and the rear core portion.
The absorbent core is positioned between the intermediate core portion and the rear core portion and has a boundary portion that crosses the absorbent core in a width direction perpendicular to the front-rear direction.
The boundary portion is provided with a boundary groove portion extending continuously or discontinuously in the width direction, and a small absorbent portion having a basis weight higher than that of the boundary groove portion.
The intermediate core portion and the rear core portion are provided with areas having a basis weight higher than that of the boundary groove portion.

As described above, according to the absorbent article of the present invention, it is possible to prevent inappropriate deformation from occurring.

1 is a perspective view showing an absorbent article according to each embodiment of the present invention; FIG. Fig. 2 is a plan view showing a state in which the absorbent article is stretched along the XY plane; 1 is a plan view showing an absorbent core of an absorbent article according to a first embodiment; FIG. (A) is a partially enlarged plan view of the vicinity of a boundary portion P2 between the intermediate core portion and the rear core portion of the absorbent core of FIG. 3, and (B) is a cut along line IVB-IVB of FIG. 1 is a partial cross-sectional view of a folded absorbent core. FIG. FIG. 3 is a diagram for explaining an absorbent core according to a second embodiment of the present invention that constitutes a part of the absorbent article shown in FIG. 5(B) is a partial cross-sectional view of the absorbent core cut along line VB-VB in FIG. 5(A). FIG. FIG. 3 is a diagram for explaining an absorbent core according to a third embodiment of the present invention that constitutes a part of the absorbent article shown in FIG. is a partially enlarged plan view of the vicinity of the boundary P2. FIG. 4 is a diagram for explaining an absorbent core according to a fourth embodiment of the present invention that constitutes a part of the absorbent article shown in FIG. 7(B) is a partial cross-sectional view of the absorbent core cut along line VIIB-VIIB in FIG. 7(A). FIG. 4 is a diagram for explaining an absorbent core according to a fifth embodiment of the present invention that constitutes a part of the absorbent article shown in FIG. is a partially enlarged plan view of the vicinity of the boundary P2. FIG. 10 is a diagram for explaining an absorbent core according to a sixth embodiment of the present invention that constitutes a part of the absorbent article shown in FIG. is a partially enlarged plan view of the vicinity of the boundary P2. Fig. 3 is a partially enlarged plan view of the vicinity of the boundary P2 between the intermediate core portion and the rear core portion of the absorbent core that constitutes a part of the absorbent article, showing another position between the constriction of the absorbent core and the boundary P2; FIG. 10 is a diagram for explaining the relationship, and a diagram for explaining another arrangement example of the boundary groove provided in the boundary P2. FIG. 11 is a schematic diagram for explaining the state of the absorbent core near the boundary P2 when the wearer wears the absorbent article according to the fourth embodiment, and only the absorbent core is shown for convenience; , lateral groove portions in the front core portion, the intermediate core portion, and the rear core portion are omitted.

<First embodiment>
[Overall configuration of napkin]
1 and 2, the X-axis direction corresponds to the front-back direction of the absorbent article 1, the Y-axis direction corresponds to the width direction, and the Z-axis direction corresponds to the up-down direction (thickness direction). Hereinafter, the absorbent article 1 will be described in the mode shown in FIG.
The absorbent article 1 of this embodiment is configured as a sanitary napkin, and is hereinafter referred to as the napkin 1 . The napkin 1 of the present embodiment may be used while sleeping, and may have a length of 30 cm or more in the front-rear direction, for example.

As shown in FIGS. 1 and 2, 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 in this embodiment.
The main body M extends in the front-rear direction and is fixed to the inner surface (wearing surface) of the wearer's underwear when worn. The main body M has an absorber and has a function of absorbing a liquid substance (hereinafter also referred to as "liquid") such as menstrual blood of the wearer.
The main body M has a front region M1, a middle region M2, and a rear region M3, which are divided along the front-rear direction.
The front region M1 is a region arranged in front of the intermediate region M2 (on the wearer's ventral side), and is configured to face the front of the wearer's excretory part when worn.
The intermediate region M2 is configured to face the wearer's excretory part when worn. Note that the intermediate region M2 may be positioned toward the front of the main body M as shown in the drawing, or may be positioned in the central portion of the main body M.
The rear area M3 is an area arranged behind the intermediate area M2 (on the wearer's back side), and is configured to face the wearer's excretory part behind when worn.

The wing portion W is configured to protrude greatly outward in the width direction in the intermediate region M2.
The side guard G is arranged so as to extend in the front-rear 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.
In addition, the napkin 1 does not need to have at least one of the wing portion W, the side guard G, and the rear flap portion F.

[Structure of each part of the napkin]
As shown in FIG. 2 , the napkin 1 includes an absorbent body (not shown), a topsheet 12 , a backsheet (not shown), a pair of side sheets 14 , and compression grooves 16 . In the main body M, the napkin 1 has a configuration in which a backsheet, an absorbent body and a topsheet 12 are laminated.

The absorber has a front-rear direction in the X-axis direction, and is arranged at the central portion in the thickness direction of the napkin 1 . The absorber absorbs the liquid from the surface on the top sheet 12 side, diffuses it inside, and retains the liquid.
The absorbent body has an absorbent core 20 and a core wrap sheet (not shown).
The absorbent core 20 has the function of absorbing and retaining liquid. The absorbent core 20 may be formed, for example, of a fiber assembly composed of hydrophilic fibers such as pulp fibers, or may have a structure in which the fiber assembly holds a water-absorbent polymer. .
The hydrophilic fibers contained in the absorbent core 20 include, for example, pulp fibers, rayon fibers, cotton fibers, cellulose-based hydrophilic fibers such as cellulose acetate, polyolefin-based fibers such as polyethylene and polypropylene, and condensation fibers such as polyester and polyamide. One or two or more selected from system fibers and the like can be used.
Examples of the water-absorbent polymer contained in the absorbent core 20 include sodium polyacrylate, acrylic acid-vinyl alcohol copolymer, sodium polyacrylate crosslinked product, starch-acrylic acid graft copolymer, isobutylene-maleic anhydride. One or more selected from copolymers, saponified products thereof, polyaspartic acid and the like can be used.
The core wrap sheet covers the absorbent core 20 and has a function of retaining the shape of the absorbent core 20, for example. The core wrap sheet is made of, for example, thin and soft paper such as tissue paper, liquid-permeable nonwoven fabric, or the like.

The surface sheet 12 is configured as a liquid-permeable sheet material and placed on the absorbent body. The surface sheet 12 forms an upper outer surface of the napkin 1 in the main body M in the thickness direction.
The backsheet is arranged to face the topsheet 12 in the thickness direction with the absorbent body interposed therebetween. The backsheet constitutes the lower outer surface of the napkin 1 in the thickness direction. The backsheet is joined to the topsheet 12 and the sidesheets 14, for example, at the peripheral edges by adhesive, heat sealing, or the like.
The pair of side sheets 14 face each other in the width direction with the top sheet 12 interposed therebetween, and are arranged at the width direction peripheral edges of the napkin 1 .
The pair of compressed groove portions 16 are configured as linear grooves formed by compressing the absorbent body and the topsheet 12 . A pair of compressed groove portions 16 are formed in the surface sheet 12, the core wrap sheet and the absorbent core 20, extend in the front-rear direction, and face each other in the width direction.

[Configuration of Absorbent Core]
As shown in FIG. 3, the absorbent core 20 includes a front core portion 21 and a rear core portion 23 facing each other in the front-rear direction, and an intermediate core portion 22 positioned between the front core portion 21 and the rear core portion 23. , has The front core portion 21 is located in the front region M1, the intermediate core portion 22 is located across the intermediate region M2 and the rear core portion 23, and the rear core portion 23 is located in the rear region M3. The absorbent core 20 has a planar shape that is symmetrical in the width direction.

The intermediate core portion 22 has a width narrower than the widths of the front core portion 21 and the rear core portion 23 . That is, the absorbent core 20 has a planar shape that is constricted in the width direction at the intermediate core portion 22 .
The intermediate core portion 22 is an excretion portion facing portion that is arranged to face the vaginal opening, which is the excretion portion of the wearer, when the napkin 1 is worn. The front core portion 21 is arranged closer to the wearer's front side (abdominal side) than the intermediate core portion 22 , and the rear core portion 23 is arranged closer to the wearer's rear side (back side) than the intermediate core portion 22 .

The front core portion 21 , the intermediate core portion 22 and the rear core portion 23 are provided with longitudinal groove portions 27 and lateral groove portions 28 , and the intermediate core portion 22 is provided with peripheral edge groove portions 29 .
Furthermore, a boundary groove portion 30 is provided at the boundary portion P1 between the front core portion 21 and the intermediate core portion 22, and a boundary groove portion 31 is provided at the boundary portion P2 between the intermediate core portion 22 and the rear core portion 23. It is The boundary part P1 and the boundary part P2 are located so as to cross the absorbent core 20 in the width direction.

In the following description, the boundary portion P1 refers to a portion that does not belong between the front core portion 21 and the intermediate core portion 22, and the boundary portion P2 refers to any portion between the rear core portion 23 and the intermediate core portion 22. part that does not belong to
In the present embodiment, as shown in FIG. 3, in both side portions in the width direction of the absorbent core 20 when viewed from above, boundary portions P2 are formed at locations where the width starts to increase rearward from the central portion in the front-rear direction. Although a positional example is given, the position of the constriction of the absorbent core 20 does not define the boundary P2. For example, as shown in FIG. 10, the boundary part P2 may be positioned in a region where the width of the absorbent core 65 gradually increases from the central part in the front-rear direction toward the rear. It should be noted that the description of each configuration denoted by the reference numerals shown in FIG. 10 will be omitted here, and will be described later.

The absorbent core 20 is divided into a plurality of blocks by low basis weight longitudinal grooves 27 , lateral grooves 28 , peripheral edge grooves 29 , and boundary grooves 30 and 31 . These grooves are configured to sink downward from the upper surface in the thickness direction (the surface positioned on the wearer's skin side) of the block portion divided into blocks. On the other hand, the block portion is configured to protrude upward in the thickness direction. Thus, the front core portion 21, the intermediate core portion 22, and the rear core portion 23 are provided with block portions, which are areas having a higher basis weight than the boundary groove portions 30 and 31, which are divided by the groove portions.

In the absorbent core 20, the regions where the grooves are formed, that is, the bottoms forming the grooves, are relatively thinner than the regions of the block portions where the grooves are not formed.
The thickness and basis weight of the absorbent core 20 are correlated. The bottom portion forming the groove portion has a relatively low basis weight compared to the block portion. As a result, the bottom of the groove is less rigid than the block. Therefore, when an external force is applied to the absorbent core 20, the absorbent core 20 is easily deformed with the groove as a deformation starting point.
From the viewpoint of ease of deformation, it is desirable that each groove has a smaller basis weight of the absorbent material than the surrounding block.

In the following description, the basis weights of the front core portion 21, the intermediate core portion 22 and the rear core portion 23 refer to the basis weights of the block portions excluding the respective groove portions 27, 28, 29, 30 and 31. Further, the block portion located in the front core portion 21 is located in the front block portion 51, the block portion located in the intermediate core portion 22 is located in the intermediate low basis weight block portion 52 or the intermediate high basis weight block portion 53, and the rear core portion 23. The block portion is called a rear block portion 54 .

The longitudinal grooves 27 extend in the front-rear direction and are arranged in plurality at intervals in the width direction. The vertical groove portion 27 is formed over the entire length in the front-rear direction so as to divide each of the front core portion 21, the intermediate core portion 22, and the rear core portion 23 in the width direction.
The lateral grooves 28 extend in the width direction and are arranged at intervals in the front-rear direction. The lateral groove portion 28 is formed over the entire length in the width direction so as to divide each of the front core portion 21, the intermediate core portion 22 and the rear core portion 23 in the front-rear direction. In this embodiment, the boundary grooves 30 and 31 formed at the boundaries P1 and P2 are not included in the lateral grooves .
The peripheral edge groove portion 29 is formed along the front-rear direction outer edge of the high basis weight portion 24 to be described later. By providing the peripheral groove portion 29 which is easy to deform with a low basis weight, the deformation around the high basis weight portion 24 is absorbed by the peripheral groove portion 29, so that the high basis weight portion 24 is less susceptible to the surrounding deformation.
The configurations such as the shape and arrangement of the vertical grooves 27, the horizontal grooves 28, and the peripheral grooves 29 are not limited to the configuration shown in FIG. set.

The boundary grooves 30 and 31 are arranged in the boundary portions P1 and P2 so as to extend in the width direction Y. As shown in FIG. In the absorbent core 20, the boundary grooves 30 and 31 are arranged parallel to the lateral grooves 28, are positioned across the width of the absorbent core 20, and are arranged at boundaries P1 and P2. The boundary groove portion 30 extends continuously along the width direction, and the boundary groove portion 31 extends discontinuously along the width direction.
The boundary portion P2 includes a boundary groove portion 31 having a lower basis weight than the block portions 52 and 53 of the intermediate core portion 22 and the block portion 54 of the rear core portion 23, and has lower rigidity than the intermediate core portion 22 and the rear core portion 23. Easy to deform. When the napkin 1 is worn, the boundary part P2 is positioned substantially corresponding to the area from the excretory part with a large curvature radius of the wearer's body toward the buttocks, and the boundary part is positioned so as to fit the skin of the area with a large curvature radius . It is easy to deform with the boundary groove portion 31 provided at P2 as a deformation starting point. A detailed configuration near the boundaries P1 and P2 will be described later.

Thus, by providing the longitudinal grooves 27, the lateral grooves 28, the peripheral grooves 29, and the boundary grooves 30 and 31, which are low in basis weight and easily deformable, the flexibility of the absorbent core 20 can be enhanced. Further, by providing the grooves, the liquid excreted into the space of the grooves can be quickly drawn into the absorbent core 20, and the liquid absorption rate can be increased. Further, by dividing the absorbent core 20 into a plurality of block portions, the surface area of the absorbent core 20 can be increased, and the liquid can be efficiently absorbed and retained.

[Configuration of rear core part]
Five vertical groove portions 27 are arranged in the rear core portion 23 . The three wide central vertical grooves 27a positioned at the center in the width direction are narrower than the pair of central vertical grooves 27a arranged to sandwich the three central vertical grooves 27a. The dimension in the width direction is longer than that of the vertical groove portion 27b. The vertical grooves 27a and 27b are simply referred to as vertical grooves 27 when there is no particular need to distinguish between them.
By providing the longitudinal groove portion 27 in the rear core portion 23, when the napkin 1 is worn, the absorbent core 20 is easily deformed so as to wrap the buttocks in the width direction with the longitudinal groove portion 27 as a deformation starting point. The gap between the skin is less likely to occur.

Furthermore, in the present embodiment, in the rear core portion 23, the central longitudinal groove portion 27a, which is wider than the side longitudinal groove portions 27b located on both side portions, is positioned at the widthwise central portion. As compared with the side portions, the areas where the thickness of the absorbent core 20 is thin increase, and the rigidity in the bending direction becomes low. Therefore, when the napkin 1 is worn and an external force is applied to the absorbent core 20 , in the rear core portion 23 , the central portion in the width direction tends to deform preferentially over the side portions. As a result, the central portion in the width direction of the rear core portion 23 is easily deformed along the intergluteal cleft, a gap between the intergluteal cleft and the wearer's skin is less likely to occur, and liquid is more efficiently absorbed by the absorbent core 20. It can be absorbed, and the occurrence of liquid leakage is suppressed.

In addition, since the rear core portion 23 is provided with the lateral groove portion 28, when the napkin 1 is worn, it is easily deformed so as to wrap the buttocks in the front-rear direction, and a gap between the buttocks and the wearer's skin is less likely to occur. As a result, the occurrence of liquid leakage is suppressed.

[Structure of intermediate core part]
As shown in FIG. 3 , the intermediate core portion 22 includes a high basis weight portion 24 and a low basis weight portion 25 . In FIG. 3, the high basis weight portion 24 is indicated by a high density dot pattern, and the low basis weight portion 25 is indicated by a low density dot pattern. The low basis weight portion 25 has a plurality of intermediate low basis weight block portions 52 and the high basis weight portion 24 has a plurality of intermediate high basis weight block portions 53 .

The high basis weight portion 24 is formed in the widthwise central portion of the intermediate core portion 22 and is arranged so as to face the wearer's excretory portion when worn. The high basis weight portion 24 extends in the front-rear direction.
The high basis weight portion 24 has a relatively high basis weight and has a higher basis weight than the front core portion 21 and the rear core portion 23 and the low basis weight portion 25 . Therefore, the high basis weight portion 24 is configured 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 .

The low basis weight portion 25 is a portion formed around the high basis weight portion 24 and having a lower basis weight than the high basis weight portion 24 . The low basis weight portion 25 is configured to sink downward from the upper surface of the high basis weight portion 24 .
In the present embodiment, the low basis weight portion 25 is arranged outside the high basis weight portion 24 in the width direction and is divided into left and right.

The intermediate core portion 22 is provided with a peripheral edge groove portion 29, one longitudinal groove portion 27c, and four lateral groove portions 28. As shown in FIG. Here, the vertical groove portion located in the intermediate core portion 22 is referred to as the vertical groove portion 27c in order to distinguish it from the vertical groove portions 27 provided in the other core portions. 27.
The vertical groove portion 27c is positioned at the center of the high basis weight portion 24 in the width direction. The longitudinal groove portion 27c is positioned on the same straight line as the longitudinal groove portion 27 positioned at the center in the width direction of the front core portion 21 and one wide central longitudinal groove portion 27a positioned at the center in the width direction of the rear core portion 23, and is located on the same straight line as the boundary groove portion. They communicate with each other via 30,31. The width of the vertical groove portion 27c is narrower than the vertical groove portion 27 of the front core portion 21 and the central vertical groove portion 27a of the rear core portion 23, which are located on the same straight line.
The four lateral grooves 28 are arranged parallel to each other at equal intervals across the intermediate core portion 22 along the width direction.

The absorbent core 20 is configured such that the basis weight increases in the order of the low basis weight portion 25, the front core portion 21, the rear core portion 23, and the high basis weight portion 24. As shown in FIG. In the absorbent core 20, the basis weight correlates with the rigidity and thickness, and in the absorbent core 20, the rigidity is higher in the order of the low basis weight portion 25, the front core portion 21 and the rear core portion 23, and the high basis weight portion 24. and the thickness is increased.
In the present embodiment, the low basis weight portion 25 having the lowest rigidity is arranged on the outer side in the width direction of the intermediate core portion 22 . Therefore, when an external force directed inward in the width direction is applied by the wearer's legs or the like, the low basis weight portion 25 is greatly compressed and deformed in the width direction.
On the other hand, due to the compressive deformation of the low basis weight portion 25, tension (tensile force) including a component in the front-rear direction (X-axis direction) is generated. A large tension that deforms the rear core portion 23 is less likely to occur. That is, the low basis weight portion 25 acts as a buffer region for an external force directed inward in the width direction, and can prevent the influence of the external force from propagating to the front core portion 21 and the rear core portion 23 .

In addition, since the external force is buffered by the low basis weight portion 25, deformation of the high basis weight portion 24 located in the widthwise central portion of the intermediate core portion 22 can also be prevented. Therefore, it is possible to prevent the formation of a gap between the excretory part and the high basis weight part 24, and to prevent liquid leakage in the width direction in addition to the front and rear.

Thus, the front core portion 21 and the rear core portion 23 are less likely to be affected by an external force directed inward in the width direction due to the low basis weight portion 25 .
Moreover, the tension associated with compressive deformation of the low basis weight portion 25 is particularly likely to act near the boundary portions P1 and P2 between the intermediate core portion 22 and the front core portion 21 and the rear core portion 23 . Therefore, in order to further reduce the influence of the tension, each part arranged near the boundaries P1 and P2 can be configured as follows.

[Structure near boundary]
As shown in FIG. 3 , the front-rear end portions of the high basis weight portion 24 have a shape in which the width gradually decreases toward the forward and rearward ends. Thereby, in the regions adjacent to the boundaries P1 and P2 of the intermediate core portion 22, the proportion of the low basis weight portion 25 acting as a buffer region for external force can be increased. Therefore, the external force buffering effect of the low basis weight portion 25 can be enhanced, and deformation of the front core portion 21 and the rear core portion 23 into inappropriate shapes can be effectively prevented.

3 and 4, two intermediate high basis weight block portions 53 located on the boundary portion P2 side of the plurality of intermediate high basis weight block portions 53 constituting the high basis weight portion 24 are replaced with intermediate high basis weight block portions. 53a. Among the rear block portions 54 located in the rear core portion 23, two rear block portions 54 adjacent to the boundary portion P2 and located in the center portion in the width direction are referred to as rear block portions 54a. When there is no particular need to distinguish between the intermediate high basis weight block portion 53a and the rear block portion 54a, they are simply referred to as the intermediate high basis weight block portion 53 and the rear block portion 54, respectively.

In the absorbent core 20, the boundary portions P1 and P2 have the same width so that the dimensions in the front-rear direction are uniform along the width direction of the absorbent core 20. As shown in FIG. The boundaries P1 and P2 are positioned parallel to the lateral grooves 28 .
The boundary portion P1 includes a boundary groove portion 30 that separates the front core portion 21 and the intermediate core portion 22 from each other.
As shown in FIGS. 3 and 4A, the boundary portion P2 is provided with a boundary groove portion 31 and a small absorbent portion 35 when viewed from above. The intermediate low basis weight block portion 52 and the intermediate high basis weight block portion 53 of the intermediate core portion 22 are separated from the rear block portion 54 of the rear core portion 23 by the boundary groove portion 31 .

The small absorbent portion 35 is positioned at the widthwise central portion of the boundary portion P2.
The small absorbent portion 35 has a higher basis weight than the boundary groove portion 31, a thickness in the thickness direction of the absorbent core 20 that is greater than that of the boundary groove portion 31, and protrudes upward in the thickness direction when viewed from the bottom surface forming the boundary groove portion 31. It is a formed protrusion.
The small absorbent portion 35 is composed of a small absorbent piece 35a and a small absorbent piece 35b. The small absorbent piece 35a and the small absorbent piece 35b are spaced apart from each other in the width direction and positioned to face each other via a second boundary groove 31b, which will be described later. The small absorbent piece 35a and the small absorbent piece 35b are positioned so as to cross the boundary P2 in the front-rear direction.

In the absorbent core 20 , the boundary grooves 31 extend along the width direction so as to cross the absorbent core 20 discontinuously. The boundary groove portion 31 is composed of a first boundary groove portion 31a, a second boundary groove portion 31b, and a third boundary groove portion 31c.
The first boundary groove portion 31a and the third boundary groove portion 31c are positioned along the width direction so as to face each other with the small absorbent portion 35 interposed therebetween.
The second boundary groove portion 31b communicates with the vertical groove portion 27c and one central vertical groove portion 27a located at the center in the width direction of the rear core portion, is located on the same straight line as these vertical groove portions, and is continuous over the entire length in the front-rear direction. One vertical groove portion 27 is formed. The second boundary groove 31b is located between the small absorbent pieces 35a and 35b.
In the region where the small absorbent portion 35 is provided in the width direction of the boundary portion P2, the groove width, which is the dimension in the front-rear direction, of the boundary groove portion 31 is shorter than the dimension in the front-rear direction of the boundary portion P2. The groove width is 0. Thus, the boundary groove portion 31 has a shape that extends discontinuously due to the position of the small absorbent portion 35 .

As shown in FIGS. 3 and 4, the intermediate high basis weight block portion 53a and the rear block portion 54a are connected to the small absorbent pieces 35a (35b), respectively, and connected via the small absorbent pieces 35a (35b). shape. The block portion 71, in which the intermediate high basis weight block portion 53a, the small absorbent piece 35a (35b), and the rear block portion 54a are connected, extends in the front-rear direction when viewed from the top, and near the central portion in the front-rear direction, It has a shape having a constricted portion where the dimension in the width direction is narrowed. The constricted portion is located at the boundary portion P2. Two block portions 71 are provided. When the absorbent core 20 is viewed from above, the two block portions 71 are located in the center of the absorbent core 20 in the width direction and are on the same straight line with respect to the vertical groove portion 27c, the second boundary groove portion 31b, and the central vertical groove portion 27a. are arranged in a symmetrical (line symmetrical) positional relationship.

As shown in FIG. 4B, in the block portion 71, the small absorbent piece 35a is configured such that the thickness gradually decreases from the intermediate high basis weight block portion 53a toward the rear block portion 54a. The same applies to the small absorbent pieces 35b. The thickness of the small absorbent portion 35 may be uniform within the XY plane. For example, the thickness of the small absorbent portion 35 may be the same as the thickness of the intermediate high basis weight block portion 53a and the rear block portion 54a, is thicker than the thickness of the bottom surface of the boundary groove portion 31, and has a basis weight greater than that of the boundary groove portion 31. should be higher.

As shown in FIG. 4A, an intermediate low basis weight block portion 52 adjacent to the boundary portion P2 of the intermediate core portion 22 and a rear block portion 54 adjacent to the boundary portion P2 of the rear core portion 23 in the width direction The rear block portions 54 other than the two rear block portions 54a located in the central portion are separated by the first boundary groove portion 31a and the third boundary groove portion 31c, and are spaced apart from each other.
The first boundary groove portion 31a communicates with the two longitudinal groove portions 27 arranged on the left side of the rear core portion 23 in FIG. 4(A). The third boundary groove portion 31 c communicates with the two longitudinal groove portions 27 arranged on the right side of the rear core portion 23 .

In this way, in the absorbent core 20, by providing the boundary groove portion 31 having a lower basis weight and lower rigidity than the block portions 52, 53 and 54 in the boundary portion P2, when the napkin 1 is attached, it is The absorptive core 20 is easily deformed along the shape of the body with the boundary groove 31 as the starting point of deformation toward the rear part, and the fit to the body is improved.
Similarly, by providing the boundary groove 30 at the boundary portion P1, the absorbent core 20 can be easily deformed along the shape of the body from the crotch portion to the front portion with the boundary groove portion 30 as a deformation starting point, and the absorbent core 20 can be easily deformed to fit the body. improve sexuality.

Further, by providing the boundary groove portion 31 , deformation that occurs in the rear core portion 23 when the napkin 1 is attached is absorbed by the boundary groove portion 31 and is less likely to propagate to the intermediate core portion 22 . For example, even if the boundary portion P2 is deformed following the deformation that occurs in the rear core portion 23, the boundary portion P2 includes the boundary groove portion 31 and has lower rigidity than the intermediate core portion 22 and the rear core portion 23. Therefore, the deformation in the boundary groove portion 31 is less likely to propagate to the intermediate core portion 22 . Similarly, deformation occurring in the intermediate core portion 22 is less likely to propagate to the rear core portion 23 .
Therefore, by providing the boundary groove portion 31, it is possible to reduce the influence of the deformation of one between the intermediate core portion 22 and the rear core portion 23 on the other, and the deformation of the other into an inappropriate shape can be reduced. It is possible to suppress breakage of the absorbent core 20 and misalignment of attachment due to the above, and to suppress liquid leakage.

Furthermore, by providing a small absorbent portion 35 having a basis weight higher than that of the boundary groove portion 31 at the boundary portion P2 where rigidity is relatively low due to the provision of the boundary groove portion 31, the small absorbent portion 35 is not provided. In comparison, the bending strength of the boundary portion P2 is improved. As a result, for example, even if an external force is applied to the boundary portion P2 due to vigorous movement of the wearer, excessive deformation at the boundary portion P2, such as twisting or tearing, can be suppressed. It is possible to suppress the occurrence of breakage etc. Since inappropriate deformation of the absorbent core 20 is less likely to occur in this manner, liquid leakage is less likely to occur.

As described above, by providing the boundary groove portion 31 and the small absorbent portion 35 at the boundary portion P2, it is possible to improve fit to the body and suppress the occurrence of kinks and tearing at the boundary portion P2. Even if the wearer moves vigorously, the absorbent core 20 is less likely to be deformed inappropriately and liquid leakage is less likely to occur.

Further, by providing the small absorbent portion 35 in the widthwise central portion of the absorbent core 20, the boundary groove portion 31 can be arranged in a symmetrical shape with respect to the widthwise centerline. Thereby, the shape retainability of the absorbent core 20 at the boundary portion P2 can be improved, and inappropriate deformation of the absorbent core 20 is suppressed. In addition, by providing the small absorbent portion 35 in the central portion in the width direction, the napkin 1 after absorbing the liquid can be well balanced between the left and right sides, and the shape retainability can be improved.

The intermediate high basis weight block portion 53a of the intermediate core portion 22 and the small absorbent piece 35a (35b) are connected, and the small absorbent piece 35a (35b) and the rear block portion 54a of the rear core portion 23 are connected. Therefore, the liquid taken in by the intermediate high basis weight block portion 53a is easily diffused quickly to the rear block portion 54a via the small absorbent pieces 35a (35b). This makes it difficult for the liquid to pool in the intermediate core portion 22, and the liquid can be efficiently diffused to the rear portion of the napkin 1, so that liquid leakage in the width direction can be suppressed.

Further, by providing the longitudinal groove portion 27 in the rear core portion 23, deformation of the rear block portion 54 is suppressed when the napkin 1 is worn.
That is, when an external force directed inward in the width direction is applied to the rear core portion 23 by the left and right buttocks of the wearer, the external force directed inward in the width direction can be buffered by the vertical groove portion 27 having a low basis weight. , the deformation of the rear block portion 54 is suppressed.

The intermediate high basis weight block portion 53a and the rear block portion 54a are connected via the small absorbent piece 35a (35b). , the deformation occurring in the high basis weight portion 24 is difficult to propagate to the rear block portion 54a due to the narrow constricted portion. It is difficult to propagate to the basis weight block portion 53a.

Further, the longitudinal grooves 27 arranged in the rear core portion 23 communicate with the boundary grooves 31 . By arranging the vertical grooves 27 in the rear core portion 23, the rear core portion 23 is easily deformed with the vertical grooves 27 as deformation starting points when an external force is applied in the width direction. At this time, the external force applied to the vertical groove portion 27 of the rear core portion 23 propagates to the boundary groove portion 31 communicating with the vertical groove portion 27 . Since the boundary groove portion 31 has low rigidity, it absorbs the transmitted external force, so that the external force is less likely to be applied to the rear block portion 54, and the breakage of the rear block portion 54 is suppressed. It is difficult to propagate to the high basis weight portion 24 of the portion 22 .

As shown in FIGS. 3 and 4A, one central longitudinal groove portion 27a positioned at the center in the width direction of the rear core portion 23 and the longitudinal groove portion 27c of the intermediate core portion 22 are separated from each other by a second boundary groove portion 31b. communicated through As a result, the liquid drawn into the space of the vertical groove portion 27c of the intermediate core portion 22 can easily diffuse rearward through the groove portion. As a result, it is difficult for the liquid to pool in the intermediate core portion 22, the liquid can be efficiently diffused to the rear portion of the napkin 1, and liquid leakage in the width direction can be suppressed.

In addition, among the five longitudinal grooves 27 positioned in the rear core portion 23, the four longitudinal grooves 27 other than the one central longitudinal groove 27a positioned at the center in the width direction are the first boundary groove 31a or the third boundary groove 31c. is in communication with Furthermore, the first boundary groove portion 31a and the third boundary groove portion 31c and the peripheral edge groove portion 29 communicate with each other. As a result, the liquid drawn into the space of the peripheral groove portion 29 of the intermediate core portion 22 diffuses into the vertical groove portions 27 arranged in the rear core portion 23 via the first boundary groove portion 31a and the third boundary groove portion 31c. easier. As a result, it is difficult for the liquid to pool in the intermediate core portion 22, the liquid can be efficiently diffused to the rear portion of the napkin 1, and liquid leakage in the width direction can be suppressed.

Further, when viewed from above, the small absorbent portion 35 is positioned on the front-rear extension line of one central vertical groove portion 27a positioned at the center of the rear core portion 23 in the width direction. As a result, the deformation of the rear core portion 23 is more likely to propagate to the intermediate core portion 22 via the small absorbent portion 35, compared to a configuration in which the central longitudinal groove portion 27a is not arranged in the center of the width direction of the rear core portion 23. Suppressed.

Further, the rear core portion 23 is provided with a plurality of lateral grooves 28 intersecting with the longitudinal grooves 27 . As a result, the external force applied to the rear core portion 23 is dispersed not only by the longitudinal groove portions 27 but also by the lateral groove portions 28 , and propagation of deformation of the rear core portion 23 to the high basis weight portion 24 is further suppressed.

Also, the boundary groove 31 may have a groove width wider than that of the lateral groove portion 28 . This facilitates deformation of the absorbent core 20 from the intermediate core portion 22 to the rear core portion 23 corresponding to the area from the excretion portion to the rear portion where the curvature radius of the wearer's body is large. The gap between is reduced. Furthermore, since the boundary groove 31 with a wide groove width reduces the influence of the deformation of the rear core portion 23 on the intermediate core 22, the high basis weight portion 24 is formed so as to swell toward the wearer's skin side. can be enhanced, and the gap between the high basis weight portion 24 and the skin is reduced.

The absorbent core 20 also has an intermediate core portion 22 narrower than the front core portion 21 and the rear core portion 23 . As a result, when the wearer's legs are closed and the crotch width is narrowed, the external force applied to the high basis weight portion 24 toward the inside in the width direction can be reduced. Moreover, the erectability of the high basis weight part 24 can be improved.

(Method for manufacturing absorbent core)
The absorbent core 20, which is partitioned into blocks by a plurality of grooves and has an uneven structure, can be manufactured, for example, by using a fiber stacking device equipped with a fiber stacking drum having a stacking recessed portion on its outer peripheral surface. In the fiber stacking device, the core material such as pulp fibers is supplied to the outer peripheral surface of the fiber stacking drum, thereby depositing the core material in the stacking concave portion. The absorbent core can be obtained by releasing the stacked fiber stack from the accumulating concave portion.
In the production of the absorbent core 20 using the fiber stacking device, in order to form the small absorbent portions 35 arranged in the boundary portion P2, the stacking recessed portion of the fiber stacking drum used is provided with a recessed portion for forming the block portion, A recess for forming a small absorbent portion is also provided. The block portions 51 to 54 and the small absorbent portion 35 are formed by depositing the core material in the concave portions of the accumulating concave portion.

<Other embodiments>
Other embodiments will be described below with reference to second to sixth embodiments. Each of the following embodiments differs from the first embodiment only in that the structure of the absorbent core near the boundary P2 between the intermediate core portion 22 and the rear core portion 23 is different. The appearance of a napkin having an absorbent core described in each embodiment below is the same as the perspective view shown in FIG. 1 and the plan view shown in FIG. Moreover, in each embodiment, the same effects as those of the first embodiment are obtained with respect to the same configuration.
Also in each of the following embodiments, as in the first embodiment, the basis weight of the block portions located in the intermediate core portion 22 and the rear core portion 23 is higher than that of the boundary groove portion.
In the following, configurations similar to those of the first embodiment are denoted by similar reference numerals, and descriptions thereof may be omitted, and different configurations will be mainly described.

<Second embodiment>
The absorbent core 60 of the napkin 1 of the second embodiment will be described with reference to FIG.
In the absorbent core 60, as shown in FIG. 5(B), the small absorbent portion 36 has a shape including the extension portion 58. As shown in FIG. The extending portion 58 is an eave-like portion in which the upper portion of the intermediate high basis weight block portion 53a located in the intermediate core portion 22 extends to the rear block portion 54a so as to cross the boundary portion P2 in the front-rear direction. A detailed description will be given below.

A boundary portion P2 of the absorbent core 60 is provided with a small absorbent portion 36 and a boundary groove portion 80 .
As shown in FIG. 5(B), the small absorbent portion 36 includes a portion 80d of the boundary groove portion 80 overlapping the extending portion 58 and the extending portion 58 when the absorbent core 60 is viewed from above.
The boundary grooves 80 are arranged in a continuous shape so as to traverse the absorbent core 60 along the width direction, but as shown in FIGS. Since the eaves-like extending portion 58 is positioned so as to cover it, the boundary groove portion 80 has a discontinuous shape due to the presence of the extending portion 58 when viewed from above.
When viewed in plan, the boundary groove portion 80 has a first boundary groove portion 80a, a second boundary groove portion 80b, and a third boundary groove portion 80c. The shape in plan view is the same as that of the first embodiment.

Here, the basis weight of the small absorbent portion 36 refers to the basis weight including both the extension portion 58 and the portion 80d of the boundary groove portion 80 that constitute the small absorbent portion 36. As shown in FIG. Further, the thickness of the small absorbent portion 36 refers to the sum of the thickness of the extension portion 58 and the thickness of the portion 80 d of the boundary groove portion 80 .
The basis weight of the small absorbent portion 36 is higher than the basis weight of the boundary groove portion 80 , and the thickness of the boundary groove portion 80 is thinner than the thickness of the small absorbent portion 36 .

The small absorbent portion 36 is composed of a small absorbent piece 36a and a small absorbent piece 36b. The small absorbent piece 36a consists of an extending portion 58 extending from one of the two intermediate high basis weight block portions 53a and a corresponding portion 80d of the boundary groove portion 80. As shown in FIG. The small absorbent piece 36b consists of an extending portion 58 extending from the other of the two intermediate high basis weight block portions 53a and a portion 80d of the boundary groove portion 80 corresponding thereto.
The extending portion 58 that constitutes the small absorbent portion 36 is connected to the intermediate high basis weight block portion 53a. Further, the extension portion 58 extends to the rear block portion 54a of the rear core portion 23 and contacts the rear block portion 54a.
Therefore, when viewed from above, the intermediate high basis weight block portion 53a, the small absorbent piece 36a (36b), and the rear block portion 54a are connected to form a block portion 72. As shown in FIG. The block portion 72 extends in the front-rear direction and has a constricted portion near the central portion in the front-rear direction, the widthwise dimension of which is narrowed, and the constricted portion is located at the boundary portion P2. Two block portions 72 are provided.

The above-described absorbent core 60 having an uneven structure can be manufactured using a fiber stacking device that includes a fiber stacking drum having a stacking recessed portion on the outer peripheral surface, as in the first embodiment.
In the production of the absorbent core 60 using the fiber stacking device, the stacking recessed portion of the fiber stacking drum used is provided with a recessed portion for forming the block portion to form the small absorbent portion 36 arranged at the boundary portion P2. No recess is provided for this purpose. By using such a fiber stacking drum and adjusting the rotation speed and direction of the fiber stacking drum, the supply amount of the core material, etc., the intermediate high basis weight of the intermediate core portion 22 can be obtained as shown in FIG. 5(B). An extending portion 58 can be formed by extending the core material from the upper portion of the block portion 53a toward the rear block portion 54b of the rear core portion 23 so as to cover a portion 80d of the boundary groove portion 80. As shown in FIG.

Thus, the small absorbent portion 36 may include an eave-shaped extension portion 58 formed by extending the core material from the intermediate high basis weight block portion 53a. In this embodiment, since the extending portion 58 extends so as to contact the rear block portion 54, the liquid taken in by the intermediate high basis weight block portion 53a passes through the small absorbent portion 36 to the rear block portion. It becomes easy to spread|diffuse to the part 54a rapidly. This makes it difficult for the liquid to pool in the intermediate core portion 22, and the liquid can be efficiently diffused to the rear portion of the napkin 1, so that liquid leakage in the width direction can be suppressed.

Further, all of the vertical groove portions 27 located in the rear core portion 23 are in communication with one continuously extending boundary groove portion 80 .
As a result, the external force applied to each vertical groove portion 27 of the rear core portion 23 is efficiently dispersed and propagated to the boundary groove portion 80, so that the external force propagated in the boundary groove portion 80 is less likely to concentrate locally. can efficiently absorb the external force propagated by Therefore, the deformation occurring in the rear core portion 23 is less likely to propagate to the intermediate core portion 22 .
Furthermore, since all of the vertical grooves 27 located in the rear core portion 23 are in communication with the boundary grooves 80, the liquid drawn into the spaces of the vertical grooves 27c of the intermediate core portion 22 and the peripheral grooves 29 will flow into the boundary grooves. It becomes easier to diffuse to the vertical groove portions 27 arranged in the rear core portion 23 via the 80 . As a result, it is difficult for the liquid to pool in the intermediate core portion 22, the liquid can be efficiently diffused to the rear portion of the napkin 1, and liquid leakage in the width direction can be suppressed.

In this embodiment, the eave-shaped extension portion 58 extends from the upper portion of the intermediate high basis weight portion 53a. may extend, and the extended portion may contact the intermediate high basis weight portion 53a.

<Third Embodiment>
The absorbent core 61 of the napkin 1 of this embodiment will be described with reference to FIG.
In the above-described embodiment, an example in which the small absorbent portion is composed of two small absorbent pieces when viewed from above has been given, but as shown in FIG. may consist of
As shown in FIG. 6 , a boundary portion P2 of the absorbent core 61 is provided with a small absorbent portion 37 and a boundary groove portion 81 .
The small absorbent portion 37 is positioned in the widthwise central portion of the boundary portion P2 and has a higher basis weight than the boundary groove portion 81 . The small absorbent portion 37 is provided so as to cross the boundary portion P2 along the front-rear direction of the boundary portion P2.
The boundary groove portion 81 is composed of a pair of boundary groove portions 81a and 81b which are positioned opposite to each other in the width direction with the small absorbent portion 37 interposed therebetween. The boundary groove portion 81 is discontinuous due to the presence of the small absorbent portion 37 and is positioned so as to cross the absorbent core 61 in the width direction.

As shown in FIG. 6, the two intermediate high basis weight block portions 53a and the two rear block portions 54a are connected to the small absorbent portion 37 and connected via the small absorbent portion 37, respectively. A block portion 73 formed by connecting two intermediate high basis weight block portions 53a, a small absorbent portion 37, and two rear block portions 54a in a row has an X shape when viewed from above, and extends left and right with respect to the center line in the width direction. It has a symmetrical shape. The block portion 73 extends in the front-rear direction and has a constricted portion near the central portion in the front-rear direction, the widthwise dimension of which is narrowed, and the constricted portion is located at the boundary portion P2.

In the block portion 73, for example, the small absorbent portion 37 may be configured such that its thickness gradually decreases from the intermediate high basis weight block portion 53a toward the rear block portion 54a, as in the first embodiment. Alternatively, the thickness in the XY plane may be uniform. Alternatively, as in the second embodiment, the extended portion formed by extending the upper portion of the intermediate high basis weight block portion 53 a may constitute a part of the small absorbent portion 37 .
Here, an example of a shape in which the thickness gradually decreases from the intermediate high basis weight block portion 53a toward the rear block portion 54a as in the first embodiment will be described.
In this embodiment, when viewed from both the plane and the cross section, one central longitudinal groove portion 27a positioned at the center in the width direction of the rear core portion 23 and the longitudinal groove portion 27c of the intermediate core portion 22 are interposed with the small absorbent portion 37 interposed therebetween. Therefore, they are not in communication with each other.

In this embodiment, when the widthwise dimensions of the small absorbent portions are the same, compared to the configuration in which the second boundary groove portion 81b is provided in the widthwise center of the small absorbent portion 35 as in the first embodiment, A large area for forming the small absorbent portion 37 can be secured. Thereby, the bending strength of the boundary portion P2 can be further improved. Further, by increasing the formation area of the small absorbent portion 35, the liquid taken in by the intermediate high basis weight block portion 53a can be diffused through the small absorbent portion 37 to the rear block portion 54a more quickly.

<Fourth Embodiment>
The absorbent core 62 of the napkin 1 of this embodiment will be described with reference to FIG.
In each of the above-described embodiments, when viewed in plan, the boundary grooves had a shape extending discontinuously. However, as shown in FIG. 62 in the width direction and continuously extending over the entire length in the width direction, and the small absorbent portion 38 is connected or connected to both the intermediate high basis weight block portion 53a and the rear block portion 54a. It may have a block shape that is not abutting and separated.

As shown in FIG. 7, the boundary portion P2 is provided with a small absorbent portion 38 and a boundary groove portion 82 .
The small absorbent portion 38 is located in the center of the boundary portion P2 in the width direction, has a higher basis weight than the boundary groove portion 82, and is thicker than the boundary groove portion 82. As shown in FIG. The dimension of the small absorbent portion 38 in the front-rear direction is shorter than the dimension of the boundary portion P2 in the front-rear direction. Although the planar shape of the small absorbent portion 38 is rectangular here, it is not limited to this.
The small absorbent portion 38 is located inside the area surrounded by the outline of the boundary groove portion 82 . The dimension of the groove width of the boundary groove portion 82 in the region where the small absorbent portion 38 is provided in the width direction of the boundary portion P2 is the difference between the dimension of the boundary portion P2 in the longitudinal direction and the dimension of the small absorbent portion 38 in the longitudinal direction. . The boundary groove portion 82 is positioned so as to continuously cross the absorbent core 62 in the width direction, and the width dimension of the groove is configured to be shorter in the center portion in the width direction.

As shown in FIGS. 7A and 7B, the two intermediate high basis weight block portions 53a and the two rear block portions 54a are not connected to the small absorbent portion 38, respectively. However, as shown in FIG. 11, when the wearer P fixes the napkin 1 to the shorts S and wears it, near the boundary P2 of the absorbent core 62, the absorbent core 62 stretches along the wearer's body. By deforming, the small absorbent portion 38 assumes a shape in contact with the intermediate high basis weight block portion 53a and the rear block portion 54a.

Therefore, when the napkin 1 is worn, the intermediate high basis weight block portion 53a of the intermediate core portion 22 and the small absorbent portion 38 are in contact with each other, and the small absorbent portion 38 and the rear block portion 54a of the rear core portion 23 are in contact with each other. The liquid taken in by the intermediate high basis weight block portion 53a is easily diffused quickly to the rear block portion 54a via the small absorbent portion 38. As shown in FIG. This makes it difficult for the liquid to pool in the intermediate core portion 22, and the liquid can be efficiently diffused to the rear portion of the napkin 1, so that liquid leakage in the width direction can be suppressed.

Further, all of the longitudinal grooves 27 located in the rear core portion 23 communicate with one continuously extending boundary groove 82 .
As a result, the external force applied to each vertical groove portion 27 of the rear core portion 23 is efficiently dispersed and propagated to the boundary groove portion 82, so that the external force propagated in the boundary groove portion 82 is less likely to concentrate locally, and the boundary groove portion External forces propagated at 82 can be efficiently absorbed. Therefore, the deformation occurring in the rear core portion 23 is less likely to propagate to the intermediate core portion 22 .
Furthermore, all the vertical grooves 27 located in the rear core portion 23, the boundary grooves 82, the vertical grooves 27c of the intermediate core portion 22, and the peripheral edge grooves 29 communicate with each other, so that the vertical grooves of the intermediate core portion 22 The liquid drawn into the space of 27 c and peripheral groove 29 is easily diffused to longitudinal grooves 27 arranged in rear core portion 23 via boundary groove 82 . As a result, it is difficult for the liquid to pool in the intermediate core portion 22, the liquid can be efficiently diffused to the rear portion of the napkin 1, and liquid leakage in the width direction can be suppressed.

In this way, even if the small absorbent portion 38 is not connected to or in contact with the middle high basis weight block portion 53a and the rear block portion 54a in the state in which the napkin 1 is stretched along the XY plane, it is possible to contact when worn. can be provided with a small absorbent portion 38.

<Fifth Embodiment>
The absorbent core 63 of the napkin 1 of this embodiment will be described with reference to FIG.
In this embodiment, as in the fourth embodiment, another configuration will be described in which the boundary grooves are formed continuously over the entire length in the width direction so as to cross the absorbent core in the width direction.
As shown in FIG. 8, in this embodiment, when viewed from above, the small absorbent portion 39 has a shape that is connected to the intermediate high basis weight block portion 53a and is not connected to the rear block portion 54a. there is
As shown in FIG. 8, a small absorbing portion 39 and a boundary groove portion 83 are provided in the boundary portion P2.
The small absorbent portion 39 is positioned in the center of the boundary portion P2 in the width direction, has a higher basis weight than the boundary groove portion 83, and is thicker than the boundary groove portion 83. As shown in FIG. The dimension of the small absorbent portion 39 in the front-rear direction is shorter than the dimension of the boundary portion P2 in the front-rear direction. The dimension of the groove width of the boundary groove portion 83 in the region where the small absorbent portion 39 is provided in the width direction of the boundary portion P2 is the difference between the front-rear dimension of the boundary portion P2 and the front-rear dimension of the small absorbent portion 39. . The boundary groove portion 83 is positioned so as to continuously cross the absorbent core 63 in the width direction, and the width of the groove is configured to be narrowed at the center portion in the width direction due to the provision of the small absorbent portion 39 .

As shown in FIG. 8, the two intermediate high basis weight block portions 53a and the small absorbent portion 39 are connected to form a block portion 74. As shown in FIG. Although the small absorbent portion 39 and the two rear block portions 54a are not connected, when the napkin 1 is worn, the absorbent core 63 near the boundary portion P2 of the absorbent core 63 is not connected, as in the fourth embodiment. By deforming along the wearer's body, the small absorbent portion 39 of the block portion 74 assumes a shape in contact with the rear block portion 54a.
Therefore, when the napkin 1 is attached, the intermediate high basis weight block portion 53a of the intermediate core portion 22 and the rear block portion 54a of the rear core portion 23 are connected via the small absorbent portion 39, so that the intermediate high basis weight block portion 53a The taken-in liquid is easily diffused quickly to the rear block portion 54a via the small absorbent portion 39. As shown in FIG. This makes it difficult for the liquid to pool in the intermediate core portion 22, and the liquid can be efficiently diffused to the rear portion of the napkin 1, so that liquid leakage in the width direction can be suppressed.

In addition, since all of the vertical grooves 27 located in the rear core portion 23 are in communication with one continuously extending boundary groove portion 83, the deformation occurring in the rear core portion 23 is transferred to the intermediate core portion 22. difficult to propagate.
Furthermore, since all the vertical grooves 27 located in the rear core portion 23, the boundary grooves 83, and the peripheral grooves 29 of the intermediate core portion 22 communicate with each other, it is pulled into the space of the peripheral grooves 29 of the intermediate core portion 22. The leaked liquid is easily diffused to the longitudinal grooves 27 arranged in the rear core portion 23 via the boundary grooves 83 . As a result, it is difficult for the liquid to pool in the intermediate core portion 22, the liquid can be efficiently diffused to the rear portion of the napkin 1, and liquid leakage in the width direction can be suppressed.

Also in this embodiment, as in the second embodiment, the small absorbent body 39 may be configured to include an eaves-like extension portion in which the upper portion of the intermediate high basis weight block portion 53a extends.

<Sixth Embodiment>
The absorbent core 64 of the napkin 1 of this embodiment will be described with reference to FIG.
In this embodiment, as in the fourth embodiment, still another configuration will be described in which the boundary groove 84 is formed continuously over the entire length in the width direction so as to cross the absorbent core 64 in the width direction.
As shown in FIG. 9, in this embodiment, when viewed from above, the small absorbent portion 40 has a shape that is connected to the rear block portion 54a and is not connected to the intermediate high basis weight block portion 53a. there is

As shown in FIG. 9, the boundary portion P2 is provided with a small absorbent portion 40 and a boundary groove portion 84 .
The small absorbent portion 40 is positioned in the center of the boundary portion P2 in the width direction, has a higher basis weight than the boundary groove portion 84, and is thicker than the boundary groove portion 84. As shown in FIG. The dimension of the small absorbent portion 40 in the front-rear direction is shorter than the dimension of the boundary portion P2 in the front-rear direction. The dimension of the groove width of the boundary groove portion 84 in the region where the small absorbent portion 40 is provided in the width direction of the boundary portion P2 is the difference between the dimension of the boundary portion P2 in the longitudinal direction and the dimension of the small absorbent portion 40 in the longitudinal direction. . The boundary groove portion 84 is positioned so as to continuously cross the absorbent core 64 in the width direction, and the width of the groove is configured to be narrowed at the center portion in the width direction due to the provision of the small absorbent portion 40 .

As shown in FIG. 9, the rear block portion 54a and the small absorbent body 40 are connected, but the intermediate high basis weight block portion 53a and the small absorbent body 40 are not connected. However, as in the fourth embodiment, when the napkin 1 is worn, the absorbent core 64 is deformed along the wearer's body in the vicinity of the boundary P2 of the absorbent core 64, causing the rear block portion 54a to deform. The connected small absorbent portion 40 has a shape that abuts on the intermediate high basis weight block portion 53a.
Therefore, when the napkin 1 is attached, the intermediate high basis weight block portion 53a of the intermediate core portion 22 and the small absorbent portion 40 connected to the rear block portion 54a are connected to each other, so that the liquid taken in by the intermediate high basis weight block portion 53a , through the small absorbent portion 40, to be rapidly diffused to the rear block portion 54a. This makes it difficult for the liquid to pool in the intermediate core portion 22, and the liquid can be efficiently diffused to the rear portion of the napkin 1, so that liquid leakage in the width direction can be suppressed.

In addition, since all of the longitudinal grooves 27 located in the rear core portion 23 are in communication with one continuously extending boundary groove portion 84 , the deformation occurring in the rear core portion 23 is transferred to the intermediate core portion 22 . difficult to propagate.
Furthermore, the five vertical grooves 27 located in the rear core portion 23 communicate with the vertical grooves 27 c and the peripheral edge grooves 29 located in the intermediate core portion 22 via boundary grooves 84 . As a result, the liquid drawn into the spaces of the vertical grooves 27 c and the peripheral grooves 29 of the intermediate core portion 22 is easily diffused to the vertical grooves 27 arranged in the rear core portion 23 via the boundary grooves 84 . As a result, it is difficult for the liquid to pool in the intermediate core portion 22, the liquid can be efficiently diffused to the rear portion of the napkin 1, and liquid leakage in the width direction can be suppressed.

Also in this embodiment, as in the second embodiment, the small absorbent body 40 is configured such that the upper portion of the rear block portion 54a includes an eave-like extension portion extending toward the intermediate core portion 22. may

Although each embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, embodiments of the present invention can be embodiments in which each embodiment is combined.
For example, in the above-described embodiment, the case where the intermediate core portion 22 is narrower than the front core portion 21 and the rear core portion 23 has been described. may

Moreover, although the shape in which the dimension in the front-back direction of the boundary part P2 becomes equal along the width direction, in other words, the shape which extends with equal width along the width direction was mentioned, However, it is not limited to this. It is good also as boundary part P2 which crosses an absorptive core in the width direction, and the dimension in the front-back direction differs in the width direction. In such a case, a portion of the boundary portion P2 where the small absorbing portion is not provided becomes the boundary groove portion. Even in such a case, excessive deformation due to the boundary portion P2 is suppressed by providing a small absorbing portion in at least a portion of the boundary portion P2.

Further, the boundary groove portion is not limited to a shape parallel to the width direction, and may be bent or curved, or the front and rear edges of the groove may be wavy.

Further, in each of the above-described embodiments, the total length of the boundary groove portions 31, 80 to 84 along the width direction is the same as the total length of the boundary portion P2 along the width direction, but the present invention is not limited to this.
For example, as shown in FIG. 10, one small absorbent portion 41 connected to the rear core portion 54 may be provided on each side portion in the width direction of the boundary portion P2. The boundary groove portion 31 of the absorbent core, which corresponds to the area from the excretory portion of the wearer's body with a large curvature radius to the rear portion, is easily deformed in the front-rear direction with the boundary groove portion 31 as the deformation starting point, and the intermediate core portion 22 ( It suffices that it is formed to have a certain amount of overall length so as to suppress the influence of the deformation of the rear core portion 23) on the rear core portion 23 (intermediate core portion 22).

Moreover, in each of the above-described embodiments, an example of a sanitary napkin is shown as an absorbent article, but the present invention is not limited to this. The absorbent article of the present invention may be, for example, an incontinence pad, a pantyhose sheet, a disposable diaper, or the like.

<Additional description of the above embodiment>
It supplements the description of the above embodiment.
(Method for measuring groove width)
The width of the groove is obtained by measuring the width at the opening of the groove. The opening width is measured by placing the absorbent core horizontally and adjusting the measurement magnification with a microscope (VHX-1000 manufactured by KEYENCE) to magnify the upper surface of the absorbent core.
Alternatively, the absorbent core 20 is cut using a single-edged razor manufactured by Feather, and the cross section of the cut sample is observed at a magnification of 20 to 100 using a microscope (VHX-1000 manufactured by KEYENCE), The groove width may be measured.

(Method for measuring the thickness of each part of the absorbent core)
The thickness of the absorbent core to be measured is measured by measuring the thickness of a small piece cut out for measuring the basis weight of each part. A small piece cut out from the absorbent core is pressed at a pressure of 5 kPa for 10 minutes, and the measurement is performed immediately after the weight is removed. 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 unloading, and use a KEYENCE non-contact laser displacement meter (laser head LK-G30, displacement meter LK-GD500) to remove the sample. Measure the thickness of When the size of the cut piece is small and it is difficult to measure with a non-contact laser displacement meter, the cross section of the cut sample is measured at 20 to 100 using a microscope (VHX-1000 manufactured by KEYENCE). It may be observed and measured at double magnification.

(Method for measuring the basis weight of each part of the absorbent core)
Each part of the absorbent core to be measured is cut using a single-edged razor manufactured by Feather to obtain a small piece having a predetermined area. The weights of these small pieces are measured using an electronic balance (A&D electronic balance GR-300, precision: 4 digits below the decimal point). The basis weight of the small piece is calculated by dividing the obtained weight by the area of the small piece of each part. The basis weight of each part is the average of the basis weights of the five small pieces.

(Numerical examples for each configuration)
Numerical examples of each configuration of the absorbent core will be described, but the numerical values are not limited to those described here. The groove width and bottom thickness of the boundary groove portion, the ratio of the boundary groove portion occupying the boundary portion P2 in the width direction, the size and thickness of the small absorbing portion, the ratio of the small absorbing portion occupying the boundary portion P2 in the width direction, etc. It is appropriately set from the point of ease of deformation of the core in the longitudinal direction, the point of suppressing the influence of deformation of the intermediate core portion 22 (rear core portion 23) on the rear core portion 23 (intermediate core portion 22), and the like. In addition, the thickness and basis weight of the bottom of each groove and the block are appropriately set so that sufficient absorption can be obtained while providing a comfortable wearing feeling with an appropriate thickness that does not give discomfort to the wearer.

Of the five vertical grooves 27 arranged in the rear core portion 23, the groove width of the pair of side vertical grooves 27b located on the lateral sides in the width direction is 0.5 mm or more, preferably 1 mm or more. And it is 2.5 mm or less, preferably 2 mm or less. Moreover, it is 0.5 mm or more and 2.5 mm or less, preferably 1 mm or more and 2 mm or less.
The groove width of the three central longitudinal grooves 27a positioned at the center in the width direction of the rear core portion 23 is 2.5 mm or more, preferably 3 mm or more. And it is 5.5 mm or less, preferably 5 mm or less. Moreover, it is 2.5 mm or more and 5.5 mm or less, preferably 3 mm or more and 5 mm or less.
The width of the vertical groove portion 27c and the groove width of the peripheral groove portion 29 in the intermediate core portion are 0.5 mm or more, preferably 1 mm or more. And it is 10 mm or less, preferably 5 mm or less. Moreover, it is 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 5 mm or less.
The groove width (dimension in the front-rear direction) of the lateral groove portion 28 is 0.5 mm or more, preferably 1 mm or more. And it is 10 mm or less, preferably 5 mm or less. Moreover, it is 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 5 mm or less.

In each of the above-described embodiments, the groove widths (dimensions in the front-rear direction) of the boundary grooves 31, 80 to 84 extending in the width direction continuously or discontinuously are uniform in the width direction regions where the small absorbent portions are not located. ing.
The groove width in the width direction of the boundary grooves 31, 80 to 84 in the region where the small absorbent portion is not located is determined by the fit to the body and the deformation generated in the intermediate core portion 22 (rear core portion 23). In order to reduce the influence on the intermediate core portion 22), it is 1 mm or more, preferably 2 mm or more.
In addition, the groove width in the width direction of the boundary grooves 31, 80 to 84 in the regions where the small absorbent portions 35 to 40 are not located is 10 mm or less from the viewpoint of suppressing deformation such as twisting of the absorbent core at the boundary portion P2. , preferably 5 mm or less. By setting such an upper limit value, the occurrence of twisting or the like at the boundary portion P2 is suppressed, and it is suppressed that the rear core portion 23 follows the deformation such as the twisting that occurs at the boundary portion P2 and causes mounting deviation of the rear core portion 23 . be able to.
The boundary groove portion 30 can also have the same groove width as the boundary groove portions 31, 80-84.

In addition, in terms of ease of deformation in the front-rear direction of the absorbent core corresponding to the area from the excretory part of the wearer's body to the rear where the radius of curvature of the wearer's body is large, the deformation of the intermediate core portion 22 (the rear core portion 23) In order to suppress the influence on the core portion 23 (intermediate core portion 22), the boundary groove portions 31, 80 to 84 in the regions where the small absorbent portions 35 to 40 are not located in the width direction are arranged with respect to the boundary portion P2 in the width direction. The occupied proportion is 60% or more, preferably 65% or more.
The ratio of the boundary grooves 31, 80 to 84 in the width direction in the region where the small absorbent portions 35 to 40 are not located to the boundary portion P2 should be less than 100%. Lower than 100% means that the small absorbers 35-40 are present at the boundary P2.

In terms of ease of deformation in the front-rear direction of the absorbent core corresponding to the area from the excretory part of the wearer's body with a large radius of curvature to the rear, the deformation of the intermediate core part 22 (rear core part 23) is the deformation of the rear core part. 23 (intermediate core portion 22), the ratio of the small absorbent portions 35 to 40 to the boundary portion P2 in the width direction is 40% or less, preferably 30% or less.
The lower limit of the ratio of the small absorbent portions 35 to 40 to the boundary portion P2 in the width direction should be greater than 0%, and is preferably 2% or more. Due to the presence of this, the bending strength of the boundary portion P2 is improved, and excessive deformation is suppressed.
The ratio of the small absorbent portions 35 to 40 in the width direction to the boundary portion P2 is greater than 0% and 40% or less, preferably 2% or more and 30% or less.
The specific numerical value of the dimension in the width direction of the small absorbent portions 35 to 40 depends on the width of the boundary portion P2. be.

The dimensions of the small absorbent portions 35 to 40 in the front-rear direction are not particularly limited, and the small absorbent portions 35 to 40 may be provided at the boundary portion P2 from the viewpoint of improving the bending strength of the boundary portion P2.
In the boundary grooves that extend continuously along the width direction when viewed from above, such as the boundary grooves 82 to 84, the groove width of the boundary grooves 82 to 84 is narrow due to the presence of the small absorbent portions 38 to 40. I wish I could.
On the other hand, in the boundary grooves 31, 80, and 81, which extend discontinuously in plan view, the dimensions of the small absorbent portions 35 to 37 in the front-rear direction are the same as those in the front-rear direction of the boundary P2. The size is the same, and the small absorbent portion may be arranged so as to cross the boundary portion P2 in the front-rear direction.

In addition to improving the bending strength of the boundary portion P2, the intermediate high basis weight block portion 53a and the rear block portion 54a each have a small absorption from the point of promoting rapid diffusion of the liquid taken in by the intermediate core portion 22 to the rear portion. It is more preferable to connect or abut on the portion, or to be able to abut when the napkin 1 is worn.
For example, like the small absorbent portions 38 to 40, the small absorbent portion and the intermediate high basis weight block portion 53a do not connect or abut each other in the front-rear direction in plan view, or the small absorbent portion and the rear block do not contact each other. If the portion 54a is not connected or in contact with the portion 54a, the absorbent core will be deformed when the napkin 1 is worn, and the small absorbent portion and the intermediate high basis weight block portion 53a will contact each other, and furthermore, the small absorbent portion and the rear block will be brought into contact with each other. It is preferable to set the size of the small absorbent portion in the front-rear direction so that the small absorbent portion abuts against the portion 54a. The dimension of the small absorbent portion in the front-rear direction can be appropriately set according to the basis weight, thickness and groove width of the boundary grooves 31, 80 to 84 and the basis weight and thickness of the small absorbent portion so that contact is possible.

The thickness of the bottoms of the lateral grooves 28, the vertical grooves 27, and the boundary grooves 30, 31, 80 to 84 is, for example, 0.5 mm or more and 6 mm or less. The basis weight of the bottom surfaces of the lateral grooves 28, the vertical grooves 27, and the boundary grooves 30, 31, 80 to 84 is, for example, 25 g/m ² or more and 300 g/m ² or less.
The thickness of the front block portion 51 of the front core portion 22 and the thickness of the rear block portion 54 of the rear core portion 23 are, for example, 2 mm or more and 10 mm or less. The basis weight of the front block portion 51 and the rear block portion 54 is, for example, 100 g/m ² or more and 500 g/m ² or less.
The thickness of the low basis weight portion 25 is, for example, 2 mm or more and 12 mm or less. The basis weight of the bottom surface of the low basis weight portion 25 is, for example, 100 g/m ² or more and 700 g/m ² or less.
The thickness of the high basis weight portion 24 is, for example, 3 mm or more and 15 mm or less. The basis weight of the bottom surface of the high basis weight portion 24 is, for example, 400 g/m ² or more and 1000 g/m ² or less.
The thickness of the small absorbent portion is, for example, 2 mm or more and 15 mm or less. The basis weight of the bottom surface of the small absorbent portion is, for example, 100 g/m ² or more and 1000 g/m ² or less.

The width of the front core portion 21 and the rear core portion 23 is 60 mm or more and 100 mm or less, preferably 70 mm or more and 90 mm or less. The width of the intermediate core portion 22 is 40 mm or more and 75 mm or less, preferably 50 mm or more and 70 mm or less.
By making the width of the intermediate core portion 22 narrower than that of the front and rear core portions 21 and 23 in this way, it is less likely to be affected by an external force exerted by the wearer's legs or the like directed inward in the width direction. It is also possible to deal with misalignment of the wearing position in the direction, and it is possible to give the wearer a sense of security.
The length of the intermediate core portion 22 in the front-rear direction is 60 mm or more and 170 mm or less, preferably 80 mm or more and 160 mm or less. As a result, the intermediate core portion 22 can be made to face the wearer's excretory portion even when there is a deviation in the mounting position in the front-rear direction.

1... Absorbent article (sanitary napkin, napkin)
Reference Signs List 20, 60, 61, 62, 63, 64, 65 Absorbent core 21 Front core part 22 Intermediate core part 23 Rear core part 24 High basis weight part (region with higher basis weight than boundary groove part)
25 ... Low basis weight portion (region with higher basis weight than boundary groove portion)
31, 80, 81, 82, 83, 84... Boundary groove portion 35, 36, 37, 38, 39, 40, 41... Small absorption portion 54... Rear block portion (region with higher basis weight than boundary groove portion)
P2... Boundary

Claims (5)

An absorbent article comprising an absorbent core having a front core portion and a rear core portion positioned at both ends in a front-rear direction, and an intermediate core portion positioned between the front core portion and the rear core portion, ,
The absorbent core has a boundary portion located between the intermediate core portion and the rear core portion and crossing the absorbent core in a width direction orthogonal to the front-rear direction,
The border is
a small absorbent portion positioned at the center of the boundary in the width direction and within the length of the boundary in the front-rear direction;
a boundary groove portion located outside the region where the small absorbent portion is located, having a basis weight lower than that of the small absorbent portion, and extending continuously in the width direction or discontinuously extending due to the presence of the small absorbent portion;
consists of
the thickness of the small absorbing portion is thicker than the thickness of the bottom surface of the boundary groove;
The intermediate core portion and the rear core portion are provided with a region having a higher basis weight than the boundary groove portion,
The intermediate core portion is
low basis weight portions having a basis weight higher than that of the boundary groove portion and located on both sides in the width direction;
The grammage is higher than that of the low grammage portion located in the central portion in the width direction, is adjacent to the boundary portion, and protrudes upward in the thickness direction from the low grammage portion, the front core portion, and the rear core portion. with a high basis weight portion
including
The small absorbent part is connected to the high basis weight part and positioned behind the high basis weight part, and only the boundary groove part is positioned behind the low basis weight part,
The rear core portion is provided with a longitudinal groove portion having a lower basis weight than a region having a higher basis weight of the rear core portion, extending along the front-rear direction, and communicating with the boundary groove portion,
The rear core portion is provided with a plurality of lateral groove portions having a lower basis weight than the region having a higher basis weight of the rear core portion and intersecting with the longitudinal groove portion,
The boundary groove portion in the region where the small absorbent portion is not located in the width direction of the boundary portion has a longer dimension in the front-rear direction than the lateral groove portion. 2. The absorbent article according to claim 1 , wherein said small absorbent portion is positioned on an extension line of said vertical groove portion. The absorbent article according to claim 1 or 2 , wherein the intermediate core portion is narrower than the front core portion and the rear core portion. The absorbent article according to any one of claims 1 to 3 , wherein one small absorbent portion is positioned along the front-rear direction. 5. The absorbent article according to any one of claims 1 to 4 , wherein the ratio of the small absorbent portions in the width direction in the boundary portion is more than 0% and 40% or less.

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