CN111148493A - Absorbent article - Google Patents

Abstract

An absorbent article according to one embodiment of the present invention includes an absorbent core. The absorbent core has a front core portion and a rear core portion located on both end portions in the longitudinal direction. The rear core has a structured surface comprising: a plurality of first groove portions arranged in a width direction orthogonal to the longitudinal direction and extending in the longitudinal direction; and one or more second groove portions provided on the center side in the width direction with respect to the first groove portions, extending in the longitudinal direction, and having a width larger than that of the first groove portions.

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article such as a sanitary napkin.

Background

An absorbent article for absorbing a liquid material such as menstrual blood includes an absorbent body having a longitudinal direction for absorbing the liquid material. The absorbent body includes an absorbent core and a core-spun sheet covering the absorbent core. The absorbent core has a structure in which grooves are formed so as to extend along the skin of a wearer wearing the absorbent article (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-112235

Disclosure of Invention

An absorbent article according to one embodiment of the present invention includes an absorbent core.

The absorbent core has a front core portion and a rear core portion located on both end portions in the longitudinal direction.

The rear core has a structured surface comprising: a plurality of first groove portions arranged in a width direction orthogonal to the longitudinal direction and extending in the longitudinal direction; and one or more second groove portions provided on the center side in the width direction with respect to the first groove portions, extending in the longitudinal direction, and having a width larger than that of the first groove portions.

Drawings

Fig. 1 is a perspective view showing an absorbent article according to a first embodiment of the present invention.

Fig. 2 is a plan view of the absorbent article.

Fig. 3 is a sectional view taken along line III-III of fig. 2.

Fig. 4 is a plan view showing the absorbent core of the absorbent article.

Fig. 5 is a schematic view showing a deformed state of the sanitary napkin when the absorbent article is worn.

Fig. 6 is a plan view of an absorbent core of a second embodiment of the present invention.

Fig. 7 is a plan view of an absorbent core of a third embodiment of the present invention.

Fig. 8 is a plan view of an absorbent core of a fourth embodiment of the present invention.

Fig. 9 is a plan view of an absorbent core of a fifth embodiment of the present invention.

Fig. 10 is a plan view of an absorbent core of a sixth embodiment of the present invention.

Fig. 11 is a plan view of an absorbent core of a seventh embodiment of the present invention.

Fig. 12 is a sectional view of an intermediate core portion of an absorbent article incorporating the absorbent core of the seventh embodiment.

Fig. 13 is a plan view of an absorbent core of an eighth embodiment of the present invention.

Fig. 14 is a partial plan view showing a modification of the absorbent core of the first embodiment.

Detailed Description

A sanitary napkin serving as an absorbent article is worn at the rear portion thereof so as to correspond to the buttocks of a wearer. In particular, in the sanitary napkin for night use, the rear portion is formed long in order to suppress liquid leakage in the rear portion, and the rear portion of the sanitary napkin is formed so as to cover almost the buttocks. Since the buttocks are shaped so as to be steeply recessed relative to the rise of the buttocks, a gap is likely to be formed between the buttocks and the sanitary napkin in the rear portion of the sanitary napkin. Therefore, liquid substances such as menstrual blood excreted from the excretory area of the wearer easily flow to the rear portion along the gluteal groove, and liquid leakage may occur in the rear portion.

The present invention relates to an absorbent article capable of suppressing liquid leakage at the rear portion.

Embodiments of the present invention will be described below with reference to the drawings.

The X, Y and Z axes are shown in the drawings.

< first embodiment >

[ integral Structure of sanitary napkin ]

Fig. 1 is a perspective view showing an absorbent article 1 according to an embodiment of the present invention. In fig. 1, the X-axis direction corresponds to the front-rear direction, the Y-axis direction corresponds to the left-right direction, and the Z-axis direction corresponds to the up-down direction.

Fig. 2 is a plan view of the absorbent article 1, and shows a configuration in which the absorbent article 1 shown in fig. 1 extends along the XY plane. In the absorbent article 1 shown in fig. 2, the X-axis direction corresponds to the longitudinal direction, the Y-axis direction corresponds to the width direction, and the Z-axis direction corresponds to the thickness direction. Hereinafter, unless otherwise specified, the longitudinal direction, the width direction, and the thickness direction refer to each direction of the absorbent article. The absorbent article 1 will be described below in the form shown in fig. 2.

The absorbent article 1 of the present embodiment is configured as a sanitary napkin, hereinafter referred to as a sanitary napkin 1.

The sanitary napkin 1 of the present embodiment may have a length of 30cm or more, for example, along the longitudinal direction, i.e., the X-axis direction, if used during daytime activities and at bedtime.

The sanitary napkin 1 in this embodiment includes a main body M, a pair of flaps W, a pair of side cuffs G, and a pair of rear flaps F.

The main body M extends in the longitudinal direction and is fixed to the inner surface (the surface to be worn) of the wearer's undergarment when worn. The main body M has an absorbent body described later, and has a function of absorbing a liquid material (hereinafter, also referred to as "liquid") such as menstrual blood of a wearer.

The main body M has a front region M1, a middle region M2, and a rear region M3 defined along the longitudinal direction.

The front region M1 is a region disposed in front of the middle region M2 (on the abdominal side of the wearer), and is configured to face the front of the excretory region of the wearer when worn.

The intermediate region M2 is configured to face the excretion region of the wearer when worn. In the case of a sanitary napkin having flaps, the region in the longitudinal direction X that overlaps the entire length of the flaps is an intermediate region M2. In the case of a sanitary napkin without flaps, the central region of the sanitary napkin, when divided into three equal parts in total length, is regarded as the middle region M2. As shown in the drawing, the intermediate region M2 may be located at a position forward of the body M or may be located at the center in the longitudinal direction of the body M.

The rear region M3 is a region disposed rearward of the intermediate region M2 (on the back side of the wearer), and is configured to face rearward of the excretory region of the wearer when worn. In the present embodiment, the rear region M3 is formed longer in the longitudinal direction than each of the front region M1 and the intermediate region M2. This can effectively prevent rearward liquid leakage.

The wing portion W is configured to greatly protrude outward in the width direction from the intermediate region M2.

The side apron G is disposed so as to extend in the longitudinal direction at the widthwise periphery of the body M including the intermediate region M2. The side cuffs G function as side gathers that rise toward the skin side by the linear elastic members being disposed in an extended state near the free end portions 141 of the side sheets 14.

The rear wing F is configured to bulge outward in the width direction from the rear region M3, and can be fixed to a region facing the buttocks on the inner surface of the underwear of the wearer when worn. This prevents the rear wing F from being displaced in the rear region M3 in accordance with the movement of the wearer when wearing the garment, and contributes to the leakage prevention function of the rear region M3.

Further, the sanitary napkin 1 may not include at least one of the wing portions W, the side barriers G, and the rear wing portions F.

[ Structure of each part of sanitary napkin ]

Fig. 3 is a sectional view taken along line III-III of fig. 2.

The sanitary napkin 1 includes an absorbent body 11, a front sheet 12, a back sheet 13, a pair of side sheets 14, an adhesive portion 15, and a compressed groove 16.

The main body M has an absorbent body 11, a front sheet 12, and a back sheet 13, and is configured by stacking these.

The absorber 11 has a longitudinal direction in the X-axis direction and is disposed in the center of the sanitary napkin 1 in the thickness direction. The absorbent body 11 absorbs discharged liquid from the surface on the topsheet 12 side, and diffuses and retains the liquid therein.

The absorbent body 11 has an absorbent core 20 and a core-spun sheet 30.

The absorbent core 20 has a function of absorbing and retaining liquid. The absorbent core 20 may be formed of a fiber aggregate made of hydrophilic fibers such as pulp fibers, or may have a structure in which the fiber aggregate holds a water-absorbent polymer. The detailed structure of the absorbent core 20 will be described later.

The absorbent core 20 has a first surface 20a facing the front sheet 12 and a second surface 20b facing the back sheet 13. In the present embodiment, the first surface 20a is configured as a structural surface having a convex structure and a groove, and the second surface 20b is configured as a flat surface.

The core sheet 30 covers the absorbent core 20, and has a function of, for example, maintaining the shape of the absorbent core 20. The core sheet 30 is formed of thin and flexible paper such as tissue paper, liquid-permeable nonwoven fabric, or the like.

The top sheet 12 is a liquid-permeable sheet and is disposed on the absorbent body 11. The front sheet 12 includes an outer surface 12a constituting a surface (a surface above in the thickness direction) of the sanitary napkin 1 in the main body M.

The back sheet 13 is disposed opposite to the front sheet 12 in the thickness direction with the absorbent body 11 interposed therebetween. The back sheet 13 includes an outer surface 13a constituting the back surface (lower surface in the thickness direction) of the sanitary napkin 1, and is disposed on the entire body M, the flaps W, and the rear flaps F.

The pair of side sheets 14 are arranged on the width-directional peripheral edge of the sanitary napkin 1 so as to face each other in the width direction with the topsheet 12 interposed therebetween.

The adhesive section 15 is configured to fix the sanitary napkin 1 to underwear, and is formed on the outer surface 13a of the back sheet 13. The adhesive portion 15 includes, for example, a main body adhesive portion 151 provided on the main body M, a wing portion adhesive portion (reference numeral 152 in fig. 12 described later) provided on the wing portion W, and a rear wing portion adhesive portion 153 provided on the rear wing portion F.

The compression grooves 16 are linear grooves formed by compression processing of the absorbent body 11 and the front sheet 12. The compression groove 16 is formed so as to surround the body M as shown in fig. 1 and 2.

The compressed grooves 16 can induce deformation in a shape conforming to the wearer when worn, and can improve the effect of preventing liquid leakage to the outside in the width direction and the longitudinal direction of the sanitary napkin 1.

[ detailed Structure of absorbent core ]

Fig. 3 is a sectional view of the rear core 23 of the sanitary napkin 1 of fig. 2.

Fig. 4 is a plan view showing the structure of the absorbent core 20 constituting a part of the absorbent body 11. Fig. 4 is a plan view of the individual absorbent cores 20 before assembly to form the sanitary napkin 1. Therefore, in the absorbent core 20 shown in fig. 4, the grooves of the compressed grooves 16 are not formed.

(Overall Structure of absorbent core)

The absorbent core 20 has a front core portion 21 and a rear core portion 23 positioned on both end portions in the longitudinal direction, and an intermediate core portion 22 positioned between the front core portion 21 and the rear core portion 23. The absorbent core 20 has a planar shape tapered at the intermediate core portion 22. The front core portions 21 of the absorbent core 20 are disposed only in the front region M1, the intermediate core portions 22 are disposed in a range from the front region M1 to the rear region M3 via the intermediate region M2, and the rear core portions 23 are disposed only in the rear region M3.

The front core portion 21 and the rear core portion 23 are located on both end portions in the longitudinal direction. The front core portion 21 and the rear core portion 23 are disposed respectively in front of and behind a excretory region of a wearer when worn.

The intermediate core 22 is located between the front core 21 and the rear core 23 and is formed to be narrower than the front core 21 and the rear core 23.

In the present embodiment, the front core portion 21 and the rear core portion 23 may have boundary portions 21a and 23a adjacent to the intermediate core portion 22 and having a width decreasing toward the intermediate core portion 22, respectively. The boundary portions 21a and 23a may be symmetrical or asymmetrical about a symmetry axis parallel to the Y-axis direction. By providing the boundary portions 21a, 23a, deformation of the boundary portions 21a, 23a against an external force inward in the width direction can be suppressed, and deformation of the intermediate core portion 22 can be effectively suppressed.

The absorbent core 20 has a first face 20a and a second face 20b opposed to each other in the thickness direction.

The first face 20a is a face for arranging one side of the front face sheet 12 via the core sheet 30. The outer surface 12a of the front sheet 12 is a skin contact surface. When the sanitary napkin 1 is worn by a wearer, the first face 20a is positioned on the skin side of the wearer.

The second surface 20b is a surface for disposing the back sheet 13 through the core sheet 30. The sanitary napkin 1 can be fixed to the inner surface of underwear by the adhesive section 15 formed on the outer surface 13a of the back sheet 13. The second face 20b is located on the inner surface side of the underwear when the sanitary napkin 1 is worn by the wearer. The second surface 20b is a substantially flat surface.

The first surface 20a has a plurality of vertical groove portions 27 and horizontal groove portions 28 intersecting each other.

In the absorbent core 20, the longitudinal groove portions 27 and the lateral groove portions 28 are arranged in line symmetry with respect to a straight line extending in the longitudinal direction (X-axis direction) passing through the center in the width direction (Y-axis direction) of the absorbent core 20.

The plurality of horizontal groove portions 28 are arranged in the longitudinal direction and extend in the width direction orthogonal to the longitudinal direction.

The plurality of vertical grooves 27 are arranged in the width direction and extend in the longitudinal direction.

By providing the vertical groove portions 27 and the horizontal groove portions 28, the flexibility of the absorbent core 20 can be improved, and by introducing liquid into the inside of the grooves, the liquid absorption rate can be improved. Further, the absorbent core 20 is divided into a plurality of block-shaped portions by the vertical groove portions 27 and the horizontal groove portions 28, so that the surface area of the absorbent core 20 is increased, and liquid can be efficiently absorbed and held.

The planar shape of the top portion of each block portion in plan view is a quadrangular shape, a substantially fan shape, or a shape in which a part of a rectangle is missing. In any of the block portions, the top portion is a substantially flat surface.

The first surface 20a has a plurality of convex block portions defined by the vertical groove portions 27 and the horizontal groove portions 28. The absorbent core 20 has an uneven structure due to grammage distribution or the like on the first surface 20 a. Since the grammage is related to the rigidity, deformation of the absorbent core 20 with respect to an external force applied when worn can be suppressed by adjusting the grammage distribution.

The intermediate core 22 includes a high grammage portion 24, a pair of low grammage portions 25. In fig. 4, the high grammage part 24 is represented by a dense dot pattern, and the low grammage part 25 is represented by a sparse dot pattern.

Among the blocks arranged in the intermediate core portion 22, the high grammage portion 24 is constituted by a group of blocks arranged in the central 2 rows. The low grammage portion 25 is formed of block-shaped portions arranged in 1 row on both sides of the high grammage portion 24.

The high grammage part 24 has a higher grammage than the low grammage part 25.

The high grammage portion 24 is disposed so as to face the excretory region of the wearer when worn.

As shown in fig. 4, the first surface 20a has a front structure surface 51 positioned in the front core portion 21, a liquid receiving surface 52 positioned in the intermediate core portion 22, and a rear structure surface 53 positioned in the rear core portion 23. The front structure surface 51 is adjacent to the liquid receiving surface 52. The rear structure surface 53 is adjacent to the liquid receiving surface 52.

The absorbent core 20 has a tapered shape in which the width D2 of the liquid receiving surface 52 is narrower than the width D1 of the front structural surface 51 and the width D3 of the rear structural surface 53.

The front structure surface 51 and the rear structure surface 53 have a flat surface with a plurality of grooves.

The high grammage portion 24 protrudes upward in the thickness direction from the low grammage portion 25, the front core portion 21, and the rear core portion 23 at the liquid receiving surface 52. Each of the high grammage portion 24 and the low grammage portion 25 has a shape in which a plurality of groove portions are formed in a flat surface. In addition, instead of the embodiment of fig. 3, the high grammage portion 24 may be a protruding portion protruding downward in the Z direction. At this time, the projecting structure projecting downward is pressed upward via the back sheet attached to the leg of the underwear, and the structure is the same as that of the embodiment of fig. 3.

In the absorbent core 20, the region in which the groove portions are formed, i.e., the bottom portions of the groove portions, are relatively thin in thickness compared to the region in which the block portions of the groove portions are not formed.

The thickness and grammage of the absorbent core 20 have a correlation. The grammage of the bottom portion forming the groove portion is relatively low compared to the bulk portion. Thus, the bottom of the groove portion is relatively less rigid than the block portion. Therefore, when an external force is applied to the absorbent core 20, the absorbent core 20 is easily deformed with the groove portions as deformation starting points.

In addition, from the viewpoint of easy deformation, it is desirable that the absorbent material of each groove portion has a smaller grammage than the surrounding block portions.

Here, the "low grammage" is a concept including a mode in which the absorbent core is not present, in addition to a mode in which the absorbent core is present. However, in the case of the material of the absorbent core, since the block-shaped portions of the absorbent core located on both sides of the groove portions are connected to each other through the groove portions, the absorbent core is less likely to be twisted, broken, or broken due to movement, and flexibility can be imparted to the absorbent core.

In the present embodiment, the groove width of the bottom portion of each groove portion is substantially the same as the groove width of the opening portion of the groove portion. The bottom of the groove is substantially parallel to the second face 20 b. The side surfaces of the groove portions forming the groove portions are substantially perpendicular to the bottom portion. The width of the groove described below indicates the width of the opening of the groove.

In addition, although the groove portion has a substantially rectangular cross section perpendicular to the longitudinal direction of the groove portion, the groove portion is not limited thereto. For example, the groove may have a V-shaped or trapezoidal cross section having a tapered side surface whose width increases from the bottom toward the opening. In this case, the absorbent core 20 also has a lower grammage and a lower rigidity in the region where the groove portions are formed than in the region where the groove portions are not formed. For example, in the case of a groove portion having a V-shaped or trapezoidal cross-sectional shape, the width of the groove portion indicates the width of the opening.

(Structure of liquid receiving surface)

Next, the vertical groove portions and the horizontal groove portions disposed on the liquid receiving surface 52 corresponding to the intermediate core portion 22 will be described in detail.

The high grammage portion 24 of the intermediate core portion 22 is formed at the widthwise central portion of the intermediate core portion 22. The high grammage portion 24 extends over the entire length of the intermediate core portion 22 in the longitudinal direction. Here, the "widthwise central portion" is a region located on the center side of the side portions including a center line bisecting the absorbent article in the widthwise direction, and refers to a region including a portion facing the excretory part of the wearer in the center core portion 22 and a region including a portion facing the gluteal groove 61 in the rear core portion 23.

The liquid receiving surface 52 includes two fourth vertical groove portions 274 serving as fourth groove portions, one fifth vertical groove portion 275 serving as a fifth groove portion, and a plurality of horizontal groove portions 28. The fourth vertical groove portion 274 and the fifth vertical groove portion 275 are thin vertical groove portions having the same width dimension and a small width.

The two fourth vertical groove portions 274 are arranged in the width direction at intervals from each other. The fourth vertical groove portion 274 has a straight portion extending in the longitudinal direction and a curved portion curved toward the center in the width direction of the liquid receiving surface 52 at both ends provided opposite to each other with the straight portion interposed therebetween.

The fourth vertical groove portions 274 are arranged to face each other across the fifth vertical groove portion 275 in the width direction, and are arranged one on each side of the fifth vertical groove portion 275.

The two fourth vertical grooves 274 form an annular groove. The region surrounded by the annular groove portion corresponds to the high grammage portion 24. The high grammage portion 24 includes 10 block-shaped portion groups arranged in the central 2 rows and defined by the fourth vertical groove portion 274, the fifth vertical groove portion 275, and the horizontal groove portion 28.

With the two fourth vertical groove portions 274, the shape of the intermediate core portion 22 can be maintained to ensure the absorption amount while suppressing the high grammage portion 24 from being deformed by the surrounding deformation.

One fifth longitudinal groove portion 275 is aligned at the center of the two fourth longitudinal groove portions 274, extending in the longitudinal direction of the intermediate core portion 22. The fifth vertical groove 275 is located at the center in the width direction of the liquid receiving surface 52. The fifth vertical groove portions 275 are aligned in the longitudinal direction inside the high grammage portion 24.

(Structure of rear structural surface)

Next, the vertical groove portion and the horizontal groove portion disposed on the rear structure surface 53 will be described in detail. The absorbent core 20 has longitudinal grooves of two width dimensions. The longitudinal groove portions having a relatively wide width are referred to as thick longitudinal groove portions, and the longitudinal groove portions having a narrow width are referred to as thin longitudinal groove portions.

In the vertical groove portion 27 arranged on the rear structure surface 53, the thick vertical groove portion is referred to as a second vertical groove portion 272, and the thin vertical groove portion is referred to as a first vertical groove portion 271. In addition, when it is not necessary to particularly distinguish between the first and second vertical groove portions 271 and 272, both are referred to as vertical groove portions 27.

In the present embodiment, five longitudinal groove portions 27 are arranged at equal intervals in the rear core portion 23, and the rigidity distribution in the width direction of the rear core portion 23 is adjusted by making three longitudinal groove portions 27 located at the center of the five longitudinal groove portions 27 thick (second longitudinal groove portions 272), and making the longitudinal groove portions 27 located on the left and right sides thin (first longitudinal groove portions 271). Here, the arrangement pitch is the distance between the centers of the adjacent vertical groove portions.

Rear structure surface 53 has two first vertical grooves 271 as first grooves, three second vertical grooves 272 as second grooves, and a plurality of horizontal grooves 28.

The second vertical groove portion 272 is a groove portion having a width larger than that of the first vertical groove portion 271. The second groove portion 272 is provided at the center side in the width direction with respect to the first groove portion 271.

As shown in fig. 4, the rear structure surface 53 is divided into three parts in the width direction, and has a center portion 237, and a first side portion 238 and a second side portion 239 which are both side portions located outside the center portion 237 in the width direction.

The three second vertical groove portions 272 are arranged in the central portion 237. The second vertical groove portion 272 in the middle of the three second vertical groove portions 272 is arranged at the center in the width direction.

One of the two first vertical groove portions 271 is arranged in each of the first side portion 238 and the second side portion 239.

As described above, in the present embodiment, since three second vertical groove portions 272 having a large width are arranged in the central portion 237 and one first vertical groove portion 271 having a small width is arranged in each of the first side portion 238 and the second side portion 239, the central portion 237 has a larger number of regions where the thickness of the absorbent core 20 is thin than the side portions 238 and 239, and therefore the rigidity in the bending direction is low. Therefore, when an external force is applied to the absorbent core 20 by wearing the sanitary napkin 1, the central portion 237 is likely to deform preferentially over the side portions 238 and 239 in the rear core portion 23.

The rear structure surface 53 has a total of 36 block-shaped portions, which are divided into 6 rows in the longitudinal direction and 6 columns in the width direction by the lateral groove portion 28, the first vertical groove portion 271, and the second vertical groove portion 272.

Two block-shaped portion groups divided by the three second vertical groove portions 272 and the horizontal groove portions 28 are arranged in the central portion 237 of the rear configuration surface 53. The block portions of the two rows of block portion groups have a width dimension shorter than the width dimension of the block portions of the other rows of block portion groups. The block groups located on both side portions 238 and 239 of the rear structure surface 53 have substantially the same dimension in the width direction. Here, the size of the block is the size of the top of the square shape of the block.

Further, the block groups located on both side portions 238 and 239 of the rear structure surface 53 may have different widthwise dimensions. For example, in the absorbent core 1020 shown in fig. 14, in each of the both side portions 238 and 239, the width dimension of the block portion positioned on the central side may be smaller than the width dimension of the block portion positioned on the side in the width direction.

Fig. 14 is a partial plan view of an absorbent core 1020 as a modification, and shows an aspect of groove portions arranged on the rear structure surface 53 of the rear core portion 23. In the absorbent core 1020 shown in fig. 14, only the arrangement pitch of the first vertical groove portions 271 and the second vertical groove portions 272 is different as compared with the absorbent core 20 shown in fig. 4.

Similarly to the absorbent core 20, the absorbent core 1020 has the two rows of the block-shaped portions arranged in the widthwise central portion 237, each block-shaped portion having a smaller size than the other block-shaped portions. That is, the block portion at the center portion 237 in the width direction is smaller than the block portions at the side portions 238 and 239.

Each block portion of the two-row block portion group arranged in the center portion 237 in the width direction is formed by two adjacent second groove portions 272 and the lateral groove portion 28.

In the absorbent core 1020, 2 rows of block-shaped part groups are arranged on both sides via two central rows of block-shaped parts. The two rows of block-shaped portions are located at the two side square portions 238, 239, respectively. In the two rows of block-shaped portions 238 and 239, the block-shaped portions of the one row of block-shaped portions located near the center in the width direction are smaller than the block-shaped portions of the one row of block-shaped portions located near the side edges in the width direction.

Each block portion of the two block portion groups arranged on the both side portions 238 and 239 is formed by at least the first vertical groove portion 271 and the horizontal groove portion 28. Specifically, each block of the block group in one row located near the side end in the width direction is formed by the side end of the rear structure surface 53, the first vertical groove 271, and the horizontal groove 28. Each block portion of the block portion group in one row located near the center portion in the width direction is formed by the adjacent first and second vertical groove portions 271, 272 and the horizontal groove portion 28.

In the absorbent core 1020 shown in fig. 14, the block portions become gradually larger from the center to the side ends in the width direction of the rear core portion 23.

The lateral grooves 28 are arranged at equal intervals on the rear structure surface 53 so that the side dimensions extending in the longitudinal direction of the respective blocks of the rear structure surface 53 are all the same.

The plurality of horizontal grooves 28 arranged on the rear structure surface 53 have the same width.

Of the plurality of horizontal groove portions 28 arranged on the first surface 20a of the absorbent core 20, the horizontal groove portion 282 arranged at the boundary between the front structure surface 51 and the liquid-receiving surface 52, and the horizontal groove portion 283 as the third groove portion arranged at the boundary between the liquid-receiving surface 52 and the rear structure surface 53 are larger in width than the other horizontal groove portions 28 and smaller in width than the second vertical groove portion 272 as the thick vertical groove portion.

Here, the lateral groove portion arranged at the boundary between the front configuration surface 51 and the liquid receiving surface 52 is denoted by reference numeral 282, and the lateral groove portion arranged at the boundary between the liquid receiving surface 52 and the rear configuration surface 53 is denoted by reference numeral 283, but the lateral groove portion is simply referred to as the lateral groove portion 28 when it is not necessary to distinguish it from other lateral groove portions 28.

The first vertical groove portion 271 is located on the extension lines 43 and 44 of the respective side edge portions 41 and 42 defining the width D2 of the liquid receiving surface 52, or located inward of the extension lines.

The absorbent core 20 is typically a mixed fiber-assembled body obtained by mixing and assembling pulp fibers and an absorbent polymer.

As the hydrophilic fiber contained in the absorbent core 20, for example, one or more selected from pulp fiber, rayon fiber, cotton fiber, cellulose-based hydrophilic fiber such as cellulose acetate, polyolefin-based fiber such as polyethylene and polypropylene, and condensation-based fiber such as polyester and polyamide can be used.

As the water-absorbent polymer contained in the absorbent core 20, for example, one or more selected from sodium polyacrylate, acrylic acid-vinyl alcohol copolymer, crosslinked sodium polyacrylate, starch-acrylic acid graft copolymer, isobutylene-maleic anhydride copolymer and saponified product thereof, polyaspartic acid, and the like can be used.

The absorbent core 20 having the uneven structure on the rear structure surface 53 can be manufactured using, for example, a fiber stacking device including a fiber stacking tube having a collecting recess on an outer peripheral surface thereof. In the fiber stacking device, a core material such as pulp fiber is supplied to the outer peripheral surface of the fiber stacking tube, and the core material is stacked in the collecting recessed portion. The absorbent core can be obtained by releasing the accumulated fibers from the collecting depressions.

[ Effect of the present embodiment ]

Fig. 5 is a schematic diagram illustrating a relationship between the deformation states of the buttocks 61 of the wearer's buttocks 60 and the rear region M3 of the sanitary napkin 1 when the sanitary napkin 1 of the present embodiment is worn.

The rear core portion 23 of the absorbent core 20 has a rear structure surface 53 including a plurality of first longitudinal groove portions 271 and a plurality of second longitudinal groove portions 272 having a width larger than that of the first longitudinal groove portions 271. The second vertical groove portion 272 is arranged at the widthwise center portion 237 of the rear core portion 23.

Thus, the rigidity in the bending direction of the central portion 237 in which the second vertical groove portions 272 are arranged is lower than that of the portion in which the first vertical groove portions 271 are arranged. Therefore, when the sanitary napkin 1 is worn by the wearer, the central portion 237 in which the second vertical groove portions 272 having a large width are arranged easily deforms so as to protrude toward the first surface 20a side in preference to the portion in which the first vertical groove portions 271 having a small width are arranged, with the second vertical groove portions 272 serving as deformation starting points, at the rear core portion 23. As shown in fig. 5, the central portion 237 of the rear core portion 23 is deformed so as to protrude toward the skin side along the cleft 61, and therefore the gap between the cleft of the wearer and the absorbent article is reduced. Thus, even if a liquid substance such as menstrual blood excreted from the excretory region of the wearer flows out to the rear portion, the liquid substance is quickly absorbed by the absorbent core 20, and liquid leakage at the rear portion can be suppressed.

Further, since the first vertical groove portions 271 having a small width are arranged on both side portions of the rear core portion 23, the first side portion 238 and the second side portion 239 follow the center portion 237 that is preferentially deformed, and are easily deformed along the rising of the buttocks. This reduces the gap between the buttocks and the absorbent article, improves the fit, and suppresses leakage in the rear portion, particularly lateral leakage.

Further, since the first side portion 238 and the second side portion 239 have higher rigidity in the bending direction than the central portion 237 and are less likely to deform, even if the central portion 237 of the absorbent core 20 deforms so as to follow the gluteal cleft 61, the first side portion 238 and the second side portion 239 are prevented from deforming excessively in conjunction with the deformation of the central portion 237. This can suppress the twisting of the rear core portion 23 of the absorbent core 20 when the sanitary napkin 1 is worn.

Further, since the central portion 237 is deformed preferentially over the first side portion 238 and the second side portion 239, it is possible to suppress the side portions from being deformed first and the sanitary napkin 1 from being twisted when the sanitary napkin 1 is worn.

As described above, in the sanitary napkin 1 of the present embodiment, the rear region is easily deformed along the shape of the buttocks including the cleft of the buttocks, and twisting can be suppressed. Thus, even if the liquid material such as menstrual blood of the wearer flows out to the rear core portion 23 of the sanitary napkin 1, the liquid material can be quickly absorbed by the absorbent body 11 deformed along the buttocks 61, and leakage can be suppressed. Further, the liquid leakage due to the twisting of the sanitary napkin 1 can be suppressed. In particular, when the sanitary napkin is worn by the wearer in a supine posture at bedtime, the liquid material is likely to flow to the back on the back side, and therefore the sanitary napkin 1 of the present embodiment is effective for suppressing the leakage of the liquid at the back at night.

In the present embodiment, since the plurality of second vertical grooves 272 having a large width are arranged in the center portion 237 in the width direction of the rear core portion 23, a plurality of deformation starting points exist in the rear core portion 23. This can enlarge a region in which the deformation of the rear core portion 23 is relatively large in the width direction.

Therefore, for example, even when the sanitary napkin 1 is worn with a shift in the width direction, any of the plurality of second vertical groove portions 272 serves as a deformation starting point, and the central portion 237 of the rear core portion 23 can be deformed in a shape along the buttocks 61. This makes it difficult to form a gap between the sanitary napkin 1 and the skin, and liquid leakage is suppressed.

In addition, in the present embodiment, since the lateral groove portions 28 are disposed in addition to the vertical groove portions 27, the sanitary napkin 1 is easily deformed along the shape of the wearing target portion of the wearer in the longitudinal direction, and the fit is improved.

In the present embodiment, as shown in fig. 4, in the rear core portion 23, the first longitudinal groove portion 271 is located inward of the extensions 43 and 44 of the respective opposite side edge portions 41 and 42 defining the width D2, which is the minimum width of the intermediate core portion 22, or on the extensions 43 and 44.

By providing the first vertical groove portion 271, which is not a thick vertical groove portion but a thin vertical groove portion, on the extension lines 43 and 44 or at a position inside the extension lines 43 and 44, the rear wing portion F is less likely to be folded inward when the sanitary napkin is worn, as compared with the case where a thick vertical groove portion is provided.

That is, when the sanitary napkin is worn, the central portion 237 of the rear core portion 23 in which the second vertical groove portion 272 is arranged as a thick vertical groove portion is more likely to be deformed preferentially than the portion in which the first vertical groove portion 271 is arranged on the extension lines 43 and 43 or on the inner side of the extension lines, and is less likely to be bent inward in the width direction on the outer side of the extension line 43, so that the rear flap portion F is inhibited from being deformed so as to be folded toward the front sheet 12 side.

In the present embodiment, the lateral groove portions 283 serving as the third groove portions are arranged between the middle core portion 22 and the rear core portion 23.

By providing the lateral groove portions 283, when the sanitary napkin 1 is worn and the central portion 237 of the rear core portion 23 of the absorbent core 20 is deformed along the gluteal groove with the second longitudinal groove portions 272 as starting points, the deformation of the high grammage portion 24 in conjunction with the deformation of the rear core portion 23 can be suppressed. Therefore, the liquid leakage due to the deformation of the high grammage portion 24 can be suppressed.

[ additional description of the present embodiment ]

The following complements the description of the present embodiment.

(method of measuring the width of groove)

The width of the groove is determined by measuring the width of the opening of the groove. The opening width was measured by horizontally placing the absorbent core, adjusting the measurement magnification with a microscope (VHX-1000 manufactured by KEYENCE corporation), and enlarging the first surface 20 a.

Alternatively, the absorbent core 20 is cut with a single-blade razor manufactured by feater, and the cross section of the cut sample is observed at a magnification of 20 to 100 times with a microscope (VHX-1000 manufactured by KEYENCE) to measure the groove width.

(method of measuring grammage of each part of absorbent core)

Each part of the absorbent core 20 to be measured was cut with a single-blade razor manufactured by feater corporation to obtain a small piece having a predetermined area. The weight of these chips was measured using an electronic balance (electronic balance GR-300, manufactured by A & D, accuracy: 4 digits below decimal point). The obtained weight was divided by the area of the small piece of each portion to calculate the grammage of the small piece. For each portion, the average of the grammage of 5 chips was set as the grammage.

(method of measuring thickness of each part of absorbent core)

The thickness of the absorbent core as a measurement object was measured by measuring the thickness of a small piece cut out for measuring the grammage for each site. The chips cut from the absorbent core were pressurized at a pressure of 5kPa for 10 minutes, and immediately after weight removal, measurement was carried out. An acrylic plate having a size of 20mm X20 mm and a thickness of 3mm was placed on the center area of the sample after weight removal, and the thickness of the sample was measured using a noncontact laser displacement meter (laser head LK-G30, displacement meter KK-GD 500) manufactured by KEYENCE. When the size of the cut piece is small and it is difficult to measure the size with a noncontact laser displacement meter, the cut piece may be measured by observing a cross section of the cut sample at a magnification of 20 to 100 times using, for example, a microscope (VHX-1000 manufactured by KEYENCE).

(numerical example of each Structure)

Numerical examples of the above absorbent core are explained. The number is not limited to the numerical values described herein. The widths of the thick longitudinal groove portion and the thin longitudinal groove portion are appropriately set in accordance with the width of the absorbent core, the depth of the groove portion, and the thickness of the bottom portion and the block portion of the groove portion. The thicknesses of the bottom and the block of the groove have a correlation with the grammage. The thickness and the grammage of the bottom and the block portions of the groove portion are appropriately set so that a suitable wearing feeling is provided with a suitable thickness that does not give a wearer a sense of discomfort, and a sufficient absorption amount is obtained.

The width a of the first vertical groove portion 271, which is a thin vertical groove portion, is preferably 0.5mm or more and 2.5mm or less, and more preferably 1mm or more and 2mm or less, in order to allow the rear portion to be easily flexibly deformed along the buttocks. In the present embodiment, the width a of the first groove 271 is set to 1.5 mm.

In order to facilitate the middle portion to be attached to the buttocks and to be easily bent and to have sufficient strength, the width b of the second vertical groove portion 272 as the thick vertical groove portion is preferably 2.5mm or more and 5.5mm or less, and more preferably 3mm or more and 5mm or less. In the present embodiment, the width of the second vertical groove portion b is set to 4mm, for example.

From the viewpoint of more easily exhibiting the above-described effects, the difference between the width a of the first vertical groove portion 271, which is a thin vertical groove portion, and the width b of the second vertical groove portion 272, which is a thick vertical groove portion, is preferably 1.5mm or more and 3.5mm or less, and more preferably 2mm or more and 3mm or less.

The width c of the lateral groove 283 arranged at the boundary between the intermediate core 22 and the rear core 23, i.e., arranged to extend in the Y-axis direction between the high grammage portion 24 and the rear core 23, is 1.5mm or more and 3.5mm or less, and more preferably 2.0mm or more and 3.0mm or less. In the present embodiment, the width c of the lateral groove 283 is set to 2.5 mm.

The width D3 of the rear core portion 23 is preferably 60mm or more and 100mm or less, more preferably 70mm or more and 90mm or less, and is set to 80mm in the present embodiment.

The arrangement pitch of the vertical groove portions 27 arranged in the rear core portion 23 is, for example, 11mm to 15mm, and is set to 13mm in the present embodiment.

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

The bottom portions of the horizontal groove portions 28 and the vertical groove portions 27 have a thickness of, for example, 0.5mm to 6.0 mm. The grammage of the bottom surfaces of the horizontal groove portion 28 and the vertical groove portion 27 is, for example, 25g/m²Above and 300g/m²The following.

The thickness of the block-like portion of the rear core portion 23 is, for example, 2mm or more and 10mm or less. The grammage of the block portion of the rear core portion 23 is, for example, 100g/m²Above and 500g/m²The following.

The width e of the fourth longitudinal groove portion 274 and the width g of the fifth longitudinal groove portion 275 of the intermediate core portion are preferably 0.5mm or more and 10mm or less, and more preferably 1mm or more and 5mm or less. In the present embodiment, the widths of the fourth and fifth vertical groove portions 274 and 275 are set to 1.5 mm.

The groove depth of the fourth and fifth vertical groove portions 274 and 275 is preferably 0.5mm or more and 10mm or less, more preferably 3mm or more and 5mm or less, and is 4mm, for example. The groove depth of the fourth vertical groove portion 274 is a distance from the opening to the bottom of the fourth vertical groove portion 274 located on the same plane as the top of the block portion of the low grammage portion 25.

The groove depth of the lateral groove portion 28 arranged inside the low grammage portion 25 is also preferably 0.5mm or more and 10mm or less, more preferably 3mm or more and 5mm or less, and is 4mm, for example.

The thickness of the low grammage portion 25 is, for example, 2mm or more and 12mm or less, and preferably 3mm or more and 10mm or less. The grammage of the bottom surface of the low grammage part 25 is, for example, 100g/m²Above and 700g/m²Hereinafter, it is preferably 200g/m²Above and 600g/m²The following.

The thickness of the high grammage portion 24 is, for example, 3mm or more and 15mm or less, and preferably 5mm or more and 13mm or less. The grammage of the bottom surface of the low grammage part 25 is, for example, 400g/m²Above and 1000g/m²Hereinafter, it is preferably 500g/m²Above and 900g/m²The following.

The difference between the thickness of the block portion of the high grammage portion 24 and the thickness of the block portion of the low grammage portion 25 is preferably 1mm or more and 3mm or less, and in the present embodiment, for example, 2 mm.

< other embodiments >

The form of arranging the groove portions on the rear structural surface of the rear core portion is not limited to the first embodiment.

The following description will be given by taking the second to eighth embodiments as examples of other embodiments.

The absorbent cores shown in the following embodiments each have a first surface and a second surface facing each other in the thickness direction, similarly to the absorbent core 20 of the first embodiment, and when the absorbent core is incorporated into a sanitary napkin, the first surface on which the topsheet is disposed has grooves.

The plan view of the absorbent core used in the description of each embodiment corresponds to the plan view of the first surface side on which the groove portions are arranged.

The absorbent core shown in each embodiment is common to the absorbent core 20 of the first embodiment in the following respects: a thick longitudinal groove portion and a thin longitudinal groove portion arranged in the rear core portion; a rough longitudinal groove portion arranged at a center portion in a width direction of the rear core portion; and the groove lines are symmetrically arranged.

When the sanitary napkin incorporating such an absorbent core is worn, the rough longitudinal groove portion becomes a deformation starting point, and the central portion of the rear core portion deforms preferentially over the other portions, and is configured to be easily deformed so as to protrude toward the first surface side.

Therefore, as shown in fig. 5, the center portion 237 of the rear core portion 23 is deformed so as to protrude toward the skin with the rough longitudinal groove portion as a deformation starting point, and the sanitary napkin is easily deformed so as to follow the buttocks 61. This reduces the gap between the buttocks 61 and the napkin, and prevents liquid from leaking rearward of the napkin.

In the following embodiments, the thin longitudinal grooves are arranged on both side portions of the rear core portion 23, so that both side portions follow the central portion that deforms preferentially over both side portions, and deform along the rise of the buttocks. This reduces the gap between the buttocks and the absorbent article, and can suppress leakage, particularly lateral leakage, in the rear portion.

Hereinafter, in each embodiment, a description will be given mainly of a configuration different from that of embodiment 1, and the same reference numerals are given to the same configurations, and the description thereof will be omitted.

< second embodiment >

Fig. 6 is a partially enlarged plan view of the rear core portion 23 of the absorbent core 120 of the second embodiment.

As shown in fig. 6, the absorbent core 120 may be formed by arranging one second vertical groove portion 272, which is a thick vertical groove portion, at the center in the width direction Y of the rear core portion 23. The second vertical groove portions 272 may be arranged so as to extend across the entire length of the absorbent core 120, passing through the front core portion 21, the intermediate core portion 22, and the rear core portion 23, without changing the width in the longitudinal direction.

Two first vertical groove portions 271 as thin vertical groove portions are arranged on both sides in the width direction with a second vertical groove portion 272 therebetween. The number of the narrow grooves is not limited to this. The second vertical groove portion 272 is also allowed to be slightly offset in the lateral direction from the center in the width direction.

< third embodiment >

As shown in fig. 7, the absorbent core 220 may have three second vertical groove portions 272, which are thick vertical groove portions, arranged at the center in the width direction of the rear core portion 23 and have different widths. The second vertical groove portion 272 located at the center of the three second vertical groove portions arranged at the center in the width direction is wider than the second vertical groove portions 272 located on both sides. The second longitudinal groove portions 272 at both sides have the same width.

A pair of first vertical groove portions 271 as thin vertical groove portions are arranged in the width direction so as to face each other with a second vertical groove portion 272 interposed therebetween. The second groove portion 272 is wider than the first groove portion 271.

In this way, when a plurality of rough longitudinal grooves are provided in the center portion in the width direction of the rear core portion 23, the widths of the rough longitudinal grooves may be different from each other. In the case where a plurality of rough longitudinal groove portions having different widths are provided, it is more preferable that the rough longitudinal groove portion having the widest width among the rough longitudinal groove portions be arranged so as to be positioned at the center of the rear core portion 23. This makes it easy for the wide rough-groove portion having the widest width to serve as a deformation starting point.

In addition, the rear core portion 23 of the absorbent core 220 has the lowest rigidity in the center portion in the Y-axis direction by making the widths of the longitudinal grooves different, and the rigidity gradually increases from the center portion to the side edge portions. In this way, the degree of deformation of the rear core portion 23 is changed in the Y-axis direction, thereby improving the fit to the buttocks. This reduces the gap between the buttocks and the napkin, and suppresses leakage, particularly lateral leakage.

< fourth embodiment >

As shown in fig. 8, the absorbent core 320 may be provided with only vertical grooves instead of horizontal grooves. In the rear core portion 23 of the absorbent core 320, three second longitudinal groove portions 272 extending in the longitudinal direction are arranged at the center in the width direction as thick longitudinal groove portions. The first vertical groove portions 271 as the thin vertical groove portions are disposed on both sides with three second vertical groove portions 272 interposed therebetween.

< fifth embodiment >

As shown in fig. 9, the absorbent core 420 may have two second vertical groove portions 272 as thick vertical groove portions arranged in the center in the width direction of the rear core portion 23. The second vertical groove portions 272 are arranged such that the middle of two second vertical groove portions 272 is located at the center in the width direction of the rear core portion 23. The first vertical groove portions 271, which are thin vertical groove portions, are arranged on both sides with two second vertical groove portions 272 interposed therebetween.

< sixth embodiment >

As shown in fig. 10, the absorbent core 520 may be formed by arranging a plurality of second vertical groove portions 272, which are thick vertical groove portions, in the rear core portion 23, the length of each of which is shorter than the entire length of the rear core portion 23 in the longitudinal direction. The first vertical groove portions 271 are arranged on both sides with three second vertical groove portions 272 interposed therebetween. In this way, the rough longitudinal groove portion arranged in the rear core portion 23 may not extend over the entire length of the rear core portion 23 in the longitudinal direction, may not reach the intermediate core portion 22 in length, or may not reach the rear end portion of the absorbent core 520.

< seventh embodiment >

Fig. 11 is a plan view of the absorbent core 620 of the present embodiment.

Fig. 2 is a plan view of a sanitary napkin 601 incorporating an absorbent core 620.

Fig. 12 is a sectional view of the intermediate core portion 22 of the sanitary napkin 601 in which the absorbent core 620 is incorporated, and is a sectional view taken along line XII-XII of the sanitary napkin 601 shown in fig. 2.

In the absorbent core 20 of the first embodiment, the fourth vertical groove portion 274 and the fifth vertical groove portion 275 have the same width dimension, and the fifth vertical groove portion 275 arranged inside the high grammage portion 24 is a thin vertical groove portion having a small width.

In contrast, in the absorbent core 620 of the present embodiment, the fifth vertical groove portions 275 arranged inside the high grammage portion 24 are thick vertical groove portions having a large width. The fifth vertical groove portion 275 is wider than the fourth vertical groove portion 274 provided around the high grammage portion 24. The rear core portion 23 of the absorbent core 620 has the same structure as the rear core portion 23 of the absorbent core 20 of the first embodiment.

As described above, in the present embodiment, the fifth vertical groove portion 275 having a width larger than that of the fourth vertical groove portion 274 provided around the high grammage portion 24 is arranged inside the high grammage portion 24.

Thus, even if the sanitary napkin is worn by the wearer at a position close to the back and the intermediate core portion 22 is provided corresponding to the buttocks of the wearer, the high grammage portion 24 is preferentially deformed so as to protrude toward the skin with the fifth longitudinal groove portion 275 as a deformation starting point. Therefore, the sanitary napkin deforms so as to follow the cleft of the buttocks, and the gap between the cleft of the buttocks and the sanitary napkin can be reduced, thereby suppressing the leakage of the liquid at the rear.

The width e of the fourth vertical groove portion, which is the thin vertical groove portion in the present embodiment, is the same as the width e of the fourth vertical groove portion described in the first embodiment.

The width g of the fifth vertical groove portion 275 is preferably 1mm or more and 10mm or less, and more preferably 1mm or more and 5mm or less. In the present embodiment, the width g of the fifth vertical groove 275 is 3 mm. The width g of the fifth vertical groove portion 275 is preferably larger than the width e of the fourth vertical groove portion 274 by 0.5mm or more and 5mm or less, and more preferably larger by 1mm or more and 3mm or less.

As shown in fig. 12, the groove depth d2 of the fifth longitudinal groove portion 275 is preferably 0.5mm or more and 10mm or less, more preferably 4mm or more and 7mm or less, and is, for example, 6 mm. The groove depth of the fifth vertical groove portion 275 is a distance from the opening to the bottom of the fifth vertical groove portion 275 located on the same plane as the top of the high grammage portion 24.

On the other hand, the groove depth d3 of the fourth vertical groove portion 274 is the same as the groove depth of the fourth vertical groove portion 274 described in the first embodiment, and is, for example, 4 mm.

The groove depth of the lateral groove portion 28 arranged inside the high grammage portion 24 is also preferably 4mm or more and 7mm or less, for example, 6 mm.

< eighth embodiment >

Fig. 13 is a plan view of the absorbent core 720 of the present embodiment.

In the absorbent core 20 of the first embodiment, the first longitudinal groove portions 271 are arranged on the extension lines 43 and 44 extending the opposite side edge portions 41 and 42 of the width D2, which is defined as the minimum width of the intermediate core portion 22, to the rear core portion 23, or inward of the extension lines, respectively.

In contrast, in the present embodiment, the first longitudinal groove portion 271 is arranged at a position outside the extension lines 43 and 44 of the both side edge portions 41 and 42 defining the width D2, which is the minimum width of the intermediate core portion 22, of the rear core portion 23. The groove portions are not arranged on the extension lines 43 and 44.

In this way, by providing the first vertical groove portion 271, which is a thin vertical groove portion, in the region outside the region sandwiched between the extension lines 43 and 44, the rear flap portion F does not fold inward when the sanitary napkin is worn, as compared with the case where a thick vertical groove portion is provided.

That is, when the sanitary napkin is worn, the central portion in the width direction in which the second vertical groove portions 272 are arranged in the rear core portion 23 of the absorbent core 20 is preferentially deformed than the portion in which the first vertical groove portions 271 are arranged in the region located outside the region sandwiched between the extension lines 43 and 44, and therefore, the deformation of the rear flap portion F so as to be folded toward the front sheet 12 side can be suppressed.

While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the embodiments of the present invention can be combined with each other.

For example, the absorbent core of each of the above embodiments has a planar shape including the narrowed portion in the central core portion, but may have a planar shape without the narrowed portion.

In still another embodiment, the thin longitudinal groove portions and the thick longitudinal groove portions may be arranged in a mixed manner in the width direction in the central portion in the width direction of the rear core portion, or the thin longitudinal groove portions may be arranged in each of a pair of side portions opposed to each other in the width direction across the central portion.

Specifically, for example, three thick longitudinal groove portions and two thin longitudinal groove portions extending in the longitudinal direction are arranged in the width direction at the center portion of the rear core portion. One thick longitudinal groove portion is arranged at the center in the width direction in the center portion, one thin longitudinal groove portion is arranged on each of both sides of the thick longitudinal groove portion, and one thick longitudinal groove portion is arranged on each of both sides of the thick longitudinal groove portion with the thick longitudinal groove portion and the thin longitudinal groove portion interposed therebetween.

In the absorbent core having such a structure, the thick longitudinal grooves are provided in the central portion, and therefore the rigidity of the central portion is lower than that of the side portions. Therefore, the central portion of the absorbent core is easily deformed along the cleft of the buttocks when worn.

The liquid-receiving surface of the absorbent core in each of the above embodiments has a high grammage part and a low grammage part. In contrast, as another embodiment, the liquid receiving surface may be configured to have a uniform grammage in the plane.

In the above-described embodiment, the grammage of the block portions of the low grammage portion of the liquid receiving surface is the same as the grammage of the block portions of the front and rear configuration surfaces, but may be different as another embodiment.

Further, in the rear core portion of the absorbent core in each of the above embodiments, the grammage of the bottom portions of the block portions and the groove portions is different, but the present invention is not limited thereto, and the grammage of the bottom portions of the block portions and the groove portions may be equal, for example. At least the bottom of the groove portion may be thinner than the block portion, and thus the region in which the groove portions are arranged is more easily deformed than the region in which the block portion is provided.

In the above-described embodiment, the absorbent core having the concave-convex structure on the rear structure surface is manufactured by using the fiber stacking device, but the present invention is not limited thereto. For example, an absorbent core having an uneven structure may be manufactured by locally pressing a groove portion on one surface of an absorbent core having a substantially flat surface with a substantially uniform in-plane thickness.

In the above embodiments, the sanitary napkin is exemplified as the absorbent article, but the present invention is not limited thereto. The absorbent article of the present invention may be, for example, an incontinence pad, a secretion pad, a disposable diaper, or the like.

The present invention also provides the following absorbent article according to the above embodiment.

< 1 > an absorbent article comprising an absorbent core having a front core portion and a rear core portion located on both end portions sides in a longitudinal direction, the rear core portion having a structural face comprising: a plurality of first groove portions arranged in a width direction orthogonal to the longitudinal direction and extending in the longitudinal direction; and one or more second groove portions provided on the center side in the width direction with respect to the first groove portions, extending in the longitudinal direction, and having a width larger than that of the first groove portions.

< 2 > the absorbent article according to the above < 1 >, wherein at least three second groove portions are arranged in the center portion in the width direction, and at least one first groove portion is arranged in each of both side portions located on the outer sides in the width direction of the center portion.

< 3 > the absorbent article according to the above < 1 > or < 2 >, wherein the absorbent core further comprises an intermediate core portion positioned between the front core portion and the rear core portion, the intermediate core portion having a liquid receiving surface adjacent to the structure surface, the liquid receiving surface having: a high grammage portion provided at a center portion in the width direction; and a low grammage portion provided around the high grammage portion and having a grammage lower than that of the high grammage portion.

< 4 > the absorbent article according to the above < 3 >, wherein the absorbent core further comprises a third groove portion having a width smaller than that of the second groove portion and provided in the width direction between the configuration surface and the liquid receiving surface.

< 5 > the absorbent article according to the above < 3 > or < 4 >, wherein the intermediate core further has: a fourth groove portion provided around the high grammage portion; and a fifth groove portion provided in the high grammage portion along the longitudinal direction and having a width larger than that of the fourth groove portion.

< 6 > the absorbent article according to the above < 5 >, wherein the width of the fifth longitudinal groove portion is larger than the width of the fourth longitudinal groove portion by 0.5mm or more and 5mm or less, preferably by 1mm or more and 3mm or less.

< 7 > the absorbent article according to the above < 5 > or < 6 >, wherein the groove depth of the fifth longitudinal groove portion is 0.5mm or more and 10mm or less, preferably 4mm or more and 7mm or less.

< 8 > the absorbent article according to any one of the above < 3 > -7 >, wherein the intermediate core portion is formed to be smaller than the widths of the front core portion and the rear core portion, and the plurality of first grooves are provided on the extension lines of the rear core portion defining both side edge portions of the minimum width of the intermediate core portion or on the inner side of the extension lines of the rear core portion.

< 9 > the absorbent article according to any one of the above < 1 > to < 8 >, wherein the absorbent core has a plurality of transverse groove portions arranged in a longitudinal direction and extending in a width direction orthogonal to the longitudinal direction.

< 10 > the absorbent article according to any one of the above < 1 > -9 >, wherein the configuration surface has a block portion formed by the lateral groove portion, the first longitudinal groove portion and the second longitudinal groove portion.

< 11 > the absorbent article according to the above < 10 >, wherein, in the configuration surface, the block portions located at the center portion in the width direction are smaller than the block portions located at the side portions in the width direction.

< 12 > the absorbent article according to the above < 10 > or < 11 >, wherein the block portions formed by at least the first groove portions and the lateral groove portions are larger in the width direction in the lateral portions than in the central portion.

< 13 > the absorbent article according to any one of the above < 10 > -12 >, wherein the block has a thickness of 2mm to 10.0 mm.

< 14 > the absorbent article according to any one of the above < 10 > to < 13 >, wherein the weight of the block portion is 100g/m²Above and 500g/m²The following.

< 15 > the absorbent article according to any one of the above < 9 > to < 14 >, wherein the lateral groove portions are arranged at equal intervals in the longitudinal direction in the configuration surface.

< 16 > the absorbent article according to any one of the above < 1 > to < 15 >, wherein the width of the first longitudinal groove portion is 0.5mm or more and 2.5mm or less, preferably 1mm or more and 2mm or less.

< 17 > the absorbent article according to any one of the above < 1 > to < 16 >, wherein the width of the second longitudinal groove portion is 2.5mm or more and 5.5mm or less, preferably 3mm or more and 5mm or less.

< 18 > the absorbent article according to any one of the above < 1 > -17 >, wherein a difference between the width of the first vertical groove portion and the width of the second vertical groove portion is 1.5mm or more and 3.5mm or less, more preferably 2mm or more and 3mm or less.

< 19 > the absorbent article according to any one of the above < 1 > -18 >, wherein the lateral groove portions are arranged at the boundary between the middle core portion and the rear core portion. .

< 20 > the absorbent article according to the above < 19 >, wherein the width of the transverse groove portion provided in the boundary is 1.5mm or more and 3.5mm or less, preferably 2.0mm or more and 3.0mm or less.

< 21 > the absorbent article according to any one of the above < 1 > -20 >, wherein the rear core portion has a width of 60mm or more and 100mm or less.

< 22 > the absorbent article according to any one of the above < 1 > - < 21 >, wherein an arrangement pitch of the longitudinal groove portions arranged in the rear core portion is 11.0mm or more and 15.0mm or less.

< 23 > the absorbent article according to any one of the above < 1 > -22 >, wherein the first and second longitudinal groove portions have a groove depth of 1.5mm or more and 6.0mm or less.

< 24 > the absorbent article according to any one of the above < 1 > -23 >, wherein the thickness of the bottom portions of the first and second longitudinal grooves is 0.5mm to 6.0 mm.

< 25 > the absorbent article according to any one of the above < 1 > to < 24 >, wherein the grammage of the bottom surfaces of the first and second longitudinal grooves is 25g/m²Above and 300g/m²The following.

< 26 > the absorbent article according to any one of the above < 1 > to < 25 >, which is a sanitary napkin.

Industrial applicability of the invention

As described above, according to the present invention, liquid leakage at the rear portion of the absorbent article can be suppressed.

Claims (26)

1. An absorbent article characterized by:

comprises an absorbent core having a front core part and a rear core part located at both end parts in a longitudinal direction,

the rear core has a structured surface comprising:

a plurality of first groove portions arranged in a width direction orthogonal to the longitudinal direction and extending in the longitudinal direction; and

and one or more second groove portions provided on the center side in the width direction of the first groove portion, extending in the longitudinal direction, and having a width larger than that of the first groove portions.

2. The absorbent article of claim 1, wherein:

at least three second grooves are arranged in the center in the width direction,

at least one of the first groove portions is arranged at each of both side portions located at the outer side in the width direction of the central portion.

3. The absorbent article according to claim 1 or 2, characterized in that:

the absorbent core further has an intermediate core portion located between the front core portion and the rear core portion,

the intermediate core has a liquid receiving surface adjacent to the structured surface,

the liquid receiving surface has: a high grammage portion provided at a center portion in the width direction; and a low grammage portion provided around the high grammage portion and having a grammage lower than that of the high grammage portion.

4. The absorbent article of claim 3, wherein:

the absorbent core further includes a third groove portion that is provided between the structure surface and the liquid receiving surface in the width direction and that is smaller in width than the second groove portion.

5. The absorbent article according to claim 3 or 4, characterized in that:

the intermediate core further has:

a fourth groove portion provided around the high grammage portion; and

and a fifth groove portion provided in the high grammage portion along the longitudinal direction and having a width larger than that of the fourth groove portion.

6. The absorbent article of claim 5, wherein:

the width of the fifth vertical groove portion is larger than the width of the fourth vertical groove portion by 0.5mm to 5mm, preferably 1mm to 3 mm.

7. The absorbent article according to claim 5 or 6, characterized in that:

the fifth vertical groove portion has a groove depth of 0.5mm to 10mm, preferably 4mm to 7 mm.

8. The absorbent article according to any one of claims 3 to 7, wherein:

the intermediate core portion is formed to be smaller than the widths of the front core portion and the rear core portion, and the plurality of first groove portions are provided on an extension line of the rear core portion defining both side edge portions of the minimum width of the intermediate core portion or on an inner side of the extension line of the rear core portion.

9. The absorbent article according to any one of claims 1 to 8, wherein:

the absorbent core has a plurality of transverse groove portions arranged in a longitudinal direction and extending in a width direction orthogonal to the longitudinal direction.

10. The absorbent article according to any one of claims 1 to 9, wherein:

the structural surface has a block portion formed by the lateral groove portion, the first vertical groove portion, and the second vertical groove portion.

11. The absorbent article of claim 10, wherein:

in the configuration surface, the block portion located at the center portion in the width direction is smaller than the block portions located at the side portions in the width direction.

12. The absorbent article according to claim 10 or 11, characterized in that:

the block portions formed by at least the first groove portion and the lateral groove portion are larger in the width direction in the lateral portions than in the central portion.

13. The absorbent article according to any one of claims 10 to 12, wherein:

the thickness of the block-shaped part is more than 2mm and less than 10.0 mm.

14. The absorbent article according to any one of claims 10 to 13, wherein:

the gram weight of the block part is 100g/m²Above and 500g/m²The following.

15. The absorbent article according to any one of claims 9 to 14, wherein:

in the above-described configuration surface, the horizontal groove portions are arranged at equal intervals in the longitudinal direction.

16. The absorbent article according to any one of claims 1 to 15, wherein:

the width of the first vertical groove portion is 0.5mm or more and 2.5mm or less, preferably 1mm or more and 2mm or less.

17. The absorbent article according to any one of claims 1 to 16, wherein:

the width of the second vertical groove portion is 2.5mm or more and 5.5mm or less, preferably 3mm or more and 5mm or less.

18. The absorbent article according to any one of claims 1 to 17, wherein:

the difference between the width of the first vertical groove portion and the width of the second vertical groove portion is 1.5mm or more and 3.5mm or less, and more preferably 2mm or more and 3mm or less.

19. The absorbent article according to any one of claims 1 to 18, wherein:

the lateral groove portions are arranged at the boundary between the middle core portion and the rear core portion.

20. The absorbent article of claim 19, wherein:

the width of the horizontal groove portion provided in the boundary is 1.5mm or more and 3.5mm or less, preferably 2.0mm or more and 3.0mm or less.

21. The absorbent article according to any one of claims 1 to 20, wherein:

the rear core portion has a width of 60mm to 100 mm.

22. The absorbent article according to any one of claims 1 to 21, wherein:

the pitch of the longitudinal grooves arranged in the rear core portion is 11.0mm to 15.0 mm.

23. The absorbent article according to any one of claims 1 to 22, wherein:

the first and second longitudinal groove portions have a groove depth of 1.5mm to 6.0 mm.

24. The absorbent article according to any one of claims 1 to 23, wherein:

the thickness of the bottom portions of the first longitudinal groove portion and the second groove portion is 0.5mm to 6.0 mm.

25. The absorbent article according to any one of claims 1 to 24, wherein:

the grammage of the bottom surfaces of the first and second longitudinal grooves is 25g/m²Above and 300g/m²The following.

26. The absorbent article according to any one of claims 1 to 25, wherein:

the absorbent article is a sanitary napkin.

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