absorbent articles

Abstract

To provide an absorbent article capable of suppressing lateral leakage.SOLUTION: An absorbent article in one embodiment comprises an absorbent core. The absorbent article has a vertical direction corresponding to a cross direction of a wearer, and a lateral direction orthogonal to the vertical direction. The absorbent core is divided into a first region, an intermediate region, and a second region sequentially along the vertical direction. The absorbent core has, on the intermediate region, a crown part whose thickness is greater than that of the first and second regions, and whose basis weight is greater than that of the first and second regions. The crown part has a first part which extends over a whole width in a lateral direction of the absorbent core. The crown part has; a plurality of high density parts which extends in the vertical direction; and a plurality of low density parts which extends in the vertical direction and whose density is lower than that of the high density parts. Thicknesses of the low density parts and high density parts are equal.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to absorbent articles such as sanitary napkins. [Background technology]

[0002] Absorbent articles for absorbing excretory fluids such as menstrual blood include an absorbent core having a longitudinal direction for absorbing excretory fluids. Some absorbent cores have a thick central portion in the longitudinal center region and grooves in the longitudinal front and rear regions so that the absorbent article fits the wearer's skin while exhibiting sufficient absorption performance (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-68440 A Summary of the Invention [Problem to be solved by the invention]

[0004] When excreted liquid is continuously supplied to an absorbent article, the absorbent article may not be able to absorb the liquid quickly enough, resulting in side leakage.

[0005] The present invention relates to an absorbent article that can suppress side leakage. [Means for solving the problem]

[0006] An absorbent article according to one aspect of the present invention includes an absorbent core. The absorbent article has a longitudinal direction corresponding to the front-to-back direction of the wearer and a lateral direction perpendicular to the longitudinal direction. The absorbent core is divided into a first region, an intermediate region, and a second region in the longitudinal direction. The absorbent core has a central peak in the intermediate region that is thicker and has a higher basis weight than the first region and the second region. The crown has a first section that spans the entire lateral width of the absorbent core. The crown portion has a plurality of high density portions extending in the vertical direction and a plurality of low density portions extending in the vertical direction and having a lower density than the high density portions. The high density portion and the low density portion have the same thickness. [Effects of the Invention]

[0007] As described above, the absorbent article of the present invention can suppress side leakage. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view of an absorbent article of the present invention as viewed from the skin side. [Figure 2] 2 is a cross-sectional view taken along line II-II in FIG. 1 (corresponding to horizontal line CL2). [Figure 3] FIG. 2 is a perspective view of an absorbent core that constitutes a part of the absorbent article. [Figure 4] FIG. 2 is a plan view of the absorbent core. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] [Overall composition of the napkin] 1, the absorbent article 1 of this embodiment comprises a main body M and a pair of wing portions W. The absorbent article 1 is configured as a sanitary napkin, and will be referred to as a napkin 1 hereinafter. The napkin 1 has a longitudinal direction X corresponding to the front-to-back direction of the wearer, and a lateral direction Y corresponding to the left-to-right direction of the wearer and perpendicular to the longitudinal direction X. Furthermore, the napkin 1 has a thickness direction Z perpendicular to both the longitudinal direction X and the lateral direction Y. In this specification, with regard to the thickness direction Z, the side closest to the wearer's skin when worn may be referred to as the upper or skin side, and the side closest to the clothing may be referred to as the lower or non-skin side. In this specification, "inner side in the lateral direction Y" means the side closer to the vertical center line CL1 that divides the napkin 1 into two equal parts in the lateral direction Y, and "outer side in the lateral direction Y" means the side away from the vertical center line CL1. In this specification, "inner side in the longitudinal direction X" means the side closer to the horizontal line CL2 that divides the excretory part-facing region C of the napkin 1, which will be described later, into two equal parts in the longitudinal direction X, and "outer side in the longitudinal direction X" means the side away from the horizontal line CL2. In this specification, "front in the longitudinal direction X" or "front" means the front in the longitudinal direction X, i.e., the direction toward the ventral side of the wearer. Similarly, "rear in the longitudinal direction X" or "rear" means the rear in the longitudinal direction X, i.e., the direction toward the dorsal side of the wearer. In this specification, the term "plan view" means a plan view seen from the thickness direction Z. The dimension in the horizontal direction Y is sometimes called the width.

[0011] As shown in FIG. 1, the main body M of the napkin 1 is divided along the longitudinal direction X into a front region F, an excretory region C, and a rear region R. The excretory area facing region C includes a region that faces the excretory area of ​​the wearer when worn. When the absorbent article is a napkin 1, the excretory area is the vaginal opening. In the napkin 1, the excretory area facing region C is a region where the wing portions W are provided. The front region F is a region that is disposed in front of the excretory region facing region C (on the wearer's abdominal side), and faces the front of the excretory region of the wearer when worn. The rear region R is a region that is disposed behind the excretory region facing region C (on the back side of the wearer), and faces the rear of the excretory region of the wearer when worn. The term "when worn" as used herein means a state in which the normal and proper wearing position (the expected wearing position of the napkin 1) is maintained.

[0012] The main body M extends along the longitudinal direction X and is fixed to the inner surface of the wearer's clothing when worn by an adhesive part (not shown) arranged on the non-skin side of the back sheet (described later). The main body M is equipped with an absorbent body 14 (described later) and has the function of absorbing excretory fluids (hereinafter also referred to as "fluid") such as menstrual blood from the wearer.

[0013] The wing portions W are configured to protrude significantly outward in the lateral direction Y in the excretory part facing region C. The wing portions W are configured by overlapping the side sheets 5 and the back sheet 3, which will be described later. In an absorbent article (napkin) 1 having wing portions W, the excretory region C is a region of the main body M between the base ends of the pair of wing portions W. The napkin 1 does not necessarily have to have the wing portions W. The napkin 1 may be configured to be long in the longitudinal direction X and have a rear flap portion in the rear region R for nighttime use.

[0014] 1 and 2, the napkin 1 comprises an absorbent body 14, a topsheet 2, a backsheet 3, and a pair of side sheets 5. In the main body M, the napkin 1 has a configuration in which the backsheet 3, the absorbent body 14, and the topsheet 2 are laminated in the thickness direction Z. These components are suitably joined together by, for example, embossing with compressed grooves (not shown), bonding with adhesives or heat sealing, or the like.

[0015] The absorbent body 14 extends in the longitudinal direction X and is disposed between the topsheet 2 and the backsheet 3. The absorbent body 14 absorbs liquid from the skin side and diffuses the liquid internally to retain it. The absorbent body 14 includes, for example, an absorbent core 4 and a core wrap sheet 13 . The absorbent core 4 may be formed of a fiber assembly made of hydrophilic fibers such as pulp fibers, or may have a configuration in which a water-absorbing polymer is held in the fiber assembly. The core wrap sheet 13 covers the absorbent core 4 and has the function of, for example, maintaining the shape of the absorbent core 4. The core wrap sheet 13 is formed, for example, from a thin, soft paper such as tissue paper or a liquid-permeable nonwoven fabric. In the absorbent body 14, the core wrap sheet 13 is typically wrapped around the absorbent core 4 in the transverse direction Y from the viewpoint of maintaining the shape. The absorbent core will be described in detail below.

[0016] The topsheet 2 is made of a liquid-permeable sheet material and is disposed above the absorbent body in the thickness direction Z. In the main body M, the skin side of the topsheet 2 forms the skin side 1a of the napkin 1 that faces the wearer's skin during wear. In addition, a sublayer sheet may be arranged between the top sheet 2 and the absorbent body to improve the permeability of liquid from the top sheet 2 to the absorbent body and to prevent liquid absorbed by the absorbent body from returning to the top sheet 2.

[0017] The backsheet 3 is disposed below the absorbent body in the thickness direction Z. The backsheet 3 forms the non-skin side 1b of the napkin 1. The back sheet 3 is formed of a sheet material having properties such as low liquid permeability, water vapor permeability, and water repellency. Examples of the sheet material that can be used include a thermoplastic resin film and a laminate of such a film and nonwoven fabric. Adhesive portions 17 and 18 are provided on the non-skin side 1b of the napkin 1, which is formed by the non-skin side of the backsheet 3, for fixing the main body M and wing portions W to clothing. When worn, the wing portions W are folded near their base ends and fixed to the crotch area of ​​clothing by the wing portion adhesive portions 17 provided on the non-skin side of the wing portions W.

[0018] The pair of side sheets 5 are arranged on the outer sides of the top sheet 2 in the lateral direction Y. The material of the side sheets 5 is preferably a sheet material that is less hydrophilic than the top sheet 2, and specific examples include nonwoven fabrics, film materials, and sheets with a laminate structure of nonwoven fabrics and film materials that are less hydrophilic than the top sheet 2. The side sheets 5 are joined to the top sheet 2, for example, with an adhesive.

[0019] [Detailed structure of the absorbent core] (Overall structure of absorbent core) The absorbent core 4 of this embodiment has a shape with a uniform width along the longitudinal direction X. As shown in Figures 3 and 4, when the absorbent core 4 is divided into three equal parts along the transverse direction Y, the central region is called a central region 8, and the regions located on both the left and right sides of the central region 8 are called side regions 9. As shown in FIGS. 1 and 3, the absorbent core 4 is divided into a first region 11, an intermediate region 6, and a second region 12 in this order from the front to the rear along the longitudinal direction X. In the absorbent core 4, the intermediate region 6 is a region where a central peak 44 (details of which will be described later) that is thicker and has a higher basis weight than other regions is located in the longitudinal direction X. In Figures 2 to 4, the region corresponding to the central peak 44 is indicated by a dot. In the absorbent core 4, the first region 11 is a region located forward of the intermediate region 6. In the absorbent core 4, the second region 12 is a region located behind the intermediate region 6. The boundary line between the first region 11 and the intermediate region 6 is a line parallel to the horizontal direction Y that passes through the frontmost part of the heightened center portion 44 in the vertical direction X. The boundary line between the second region 12 and the intermediate region 6 is a line parallel to the horizontal direction Y that passes through the rearmost part of the heightened center portion 44 in the vertical direction X. In this embodiment, the heightened center portion 44 has a substantially hexagonal shape in a plan view, and the frontmost part and the rearmost part of the heightened center portion 44 in the vertical direction X each correspond to the vertices of the substantially hexagonal shape of the heightened center portion 44.

[0020] In the napkin 1, the intermediate region 6 of the absorbent core 4 is located in the longitudinal direction X over a part of the front region F and the entire length of the excretory region C in a plan view. In the napkin 1, the first region 11 of the absorbent core 4 is located in the front region F, and the second region 12 is located in the rear region R in a plan view. That is, when the napkin 1 is worn, the intermediate region 6 of the absorbent core 4 is located mainly in the wearer's excretory area, and the first region 11 and the second region 12 are located in front of and behind the wearer's excretory area, respectively.

[0021] The absorbent core 4 has a plurality of low basis weight grooves recessed toward the non-skin side in the front region F and the rear region R, and the absorbent core 4 has a plurality of block sections partitioned by the low basis weight grooves. The provision of the low basis weight grooves increases the flexibility of the absorbent core 4 and increases the liquid absorption rate. Hereinafter, the low basis weight grooves will be simply referred to as "grooves."

[0022] In the napkin 1, the grooves are a front groove 47, a rear groove 49, a front boundary lateral groove 41F, a rear boundary lateral groove 41R, a front median-high boundary groove 42F, and a rear median-high boundary groove 42R. In the napkin 1, the block portions are a front block portion 46, a rear block portion 48, a crown adjacent portion 45, and a crown portion 44. Details will be described later. In the absorbent core 4, the regions where the grooves are formed, i.e., the bottom portions where the grooves are formed, are relatively thinner than the regions of the block portions where no grooves are formed. Also, in the absorbent core 4, the bottom portions where the grooves are formed have a lower basis weight than the block portions. As a result, the bottom portions of the grooves are less rigid than the block portions, and when an external force is applied to the absorbent core 4, the absorbent core 4 is more likely to deform, with the grooves acting as deformation starting points.

[0023] (Intermediate area configuration) As shown in Figures 1 and 3, in the absorbent core 4, when viewed in a plane, the front end 44a of the central high portion 44 located in the intermediate region 6 has a convex shape that protrudes forward, and the rear end 44b has a convex shape that protrudes backward. 1, the crown 44 has an overall hexagonal shape that is a combination of a rectangular crown central portion 44C as a first portion and an isosceles triangular forward convex portion 44F and an inverted isosceles triangular rearward convex portion 44R as a second portion. In FIG. 1, the imaginary boundary between the crown central portion 44C and the frontward convex portion 44F and the imaginary boundary between the crown central portion 44C and the rearward convex portion 44R are indicated by dashed dotted lines. The first portion, ie, the central portion 44C, is a portion of the central portion 44 where the central portion exists across the entire width of the absorbent core 4 in the lateral direction Y. The front convex portion 44F and the rear convex portion 44R as the second portions are portions in the front and rear of the central portion 44, respectively, whose widths decrease outward in the longitudinal direction X.

[0024] As shown in FIGS. 1 and 3, in the absorbent core 4, the intermediate region 6 has a medial portion 44, a medial adjacent portion 45, a front medial boundary groove portion 42F, and a rear medial boundary groove portion 42R.

[0025] As shown in FIG. 1, the intermediate region 6 is further divided in the longitudinal direction X into an intermediate first region 61, a front intermediate second region 62F, and a rear intermediate second region 62R. The intermediate first region 61 is a region where a crowned central portion 44C is located as a first region of the crowned portion 44 across the entire width of the absorbent core 4 in the lateral direction Y. The front middle second region 62F is a region where the front convex portion 44F, which serves as the second portion of the central high portion 44, is located. The rear middle second region 62R is a region where the rear convex portion 44R, which serves as the second portion of the central high portion 44, is located. Along the longitudinal direction X, the intermediate first region 61 is located between the front intermediate second region 62F and the rear intermediate second region 62R.

[0026] The intermediate first region 61 has the crowned central portion 44C of the crowned portion 44. The front intermediate second region 62F has a front convex portion 44F of the crown portion 44, two crown adjacent portions 45 located in the front, and a front crown boundary groove portion 42F. The rear intermediate second region 62R has a rear convex portion 44R of the crown portion 44, two crown adjacent portions 45 located rearward, and a rear crown boundary groove portion 42R.

[0027] ((Junior and Senior High School)) As shown in FIG. 1, in the intermediate region 6 of the absorbent core 4, the centrally-high portion 44 is a block portion defined and formed by a front centrally-high boundary groove portion 42F and a rear centrally-high boundary groove portion 42R. 3, the central portion 44 has a higher basis weight and a greater thickness than the first region 11 and the second region 12. Therefore, in the napkin 1, the central portion 44 of the absorbent core 4 protrudes toward the skin in the thickness direction Z. Note that "having a higher basis weight than the first and second regions" means that, when grooves are provided in the first and second regions, the basis weight is higher than the basis weight of the first and second regions excluding the grooves. Also, "having a thicker thickness than the first and second regions" means that, when grooves are provided in the first and second regions, the thickness is higher than the thickness of the first and second regions excluding the grooves. In the napkin 1 of this embodiment, "having a higher basis weight and a thicker thickness than the first region 11 and the second region 12" means "having a higher basis weight and a thicker thickness than the front block portion 46 of the first region 11 and the rear block portion 48 of the second region 12."

[0028] The center portion 44C, which constitutes part of the center portion 44, has a maximum width portion where the width (width in the horizontal direction Y) of the center portion 44 is at its widest. In the center portion 44C, the width of the center portion 44 and the width of the absorbent core 4 are the same.

[0029] The front convex portion 44F, which constitutes a part of the center portion 44, is located in front of the center portion 44C. The front convex portion 44F has a shape whose width decreases forward in the vertical direction X. The front convex portion 44F has an isosceles triangular shape. In the isosceles triangular front convex portion 44F, the apex angle is located forward of the base, and the base coincides with a side parallel to the lateral direction Y located in front of the rectangular crown central portion 44C. The apex angle of the isosceles triangular front convex portion 44F corresponds to the foremost part of the crown 44. The two equal sides of the isosceles triangular front convex portion 44F form the front end portion 44a of the crown 44.

[0030] The rear convex portion 44R, which constitutes a part of the center portion 44, is located rearward of the center portion 44C. The rear convex portion 44R has a shape whose width decreases rearward in the longitudinal direction X. The rear convex portion 44R has an inverted isosceles triangle shape. In the inverted isosceles triangle-shaped rear convex portion 44R, the apex angle is located rearward of the base, and the base coincides with a side parallel to the lateral direction Y located rearward of the rectangular crown central portion 44C. The apex angle of the inverted isosceles triangle-shaped rear convex portion 44R corresponds to the rearmost part of the crown 44. The two equal sides of the inverted isosceles triangle-shaped rear convex portion 44R form the rear end 44b of the crown 44.

[0031] In this embodiment, the front end 44a and rear end 44b of the centrally elevated portion 44 each have an inverted V-shape or V-shape formed by two connected straight lines with different inclinations, but the shapes of the front end 44a and rear end 44b may be other shapes, such as an arc shape.

[0032] As shown in FIGS. 2 and 3, the crown 44 has a plurality of high density portions 10 and a plurality of low density portions 7. 2 to 4, the peaked portion 44 is indicated by dots, the high density portion 10 is indicated by dense dots, and the low density portion 7 is indicated by sparse dots. The high density portion 10 is a region where the pulp fiber density is higher than that of the low density portion 7. The high density portion 10 extends continuously in the longitudinal direction X over the entire length of the center portion 44 from the front end 44a to the rear end 44b. The low-density portion 7 extends continuously in the longitudinal direction X over the entire length of the center portion 44 from the front end 44a to the rear end 44b. The plurality of high density portions 10 and the plurality of low density portions 7 are alternately positioned along the lateral direction Y. As shown in FIGS. 2 and 3, the low-density portion 7 and the high-density portion 10 have the same thickness (height) in the thickness direction Z, and the crown portion 44 has the same thickness within its plane (in the XY plane). Here, the term "same thickness" for an absorbent core includes an error range of ±1.5 mm.

[0033] In the absorbent core 4, the center-height portion 44 having two regions with different pulp fiber densities (high-density portion 10 and low-density portion 7) is manufactured by compressing the region that will become the low-density portion 7 and the region that will become the high-density portion 10, which have different basis weights and thicknesses, so that the difference in thickness between these two regions is eliminated (so that the thicknesses become the same). The manufacturing method will be described later.

[0034] As shown in FIGS. 2 to 4, in the napkin 1, the central portion 44 of the absorbent core 4 has two high-density portions 10 and three low-density portions 7. In the center portion 44, in a plan view, two high-density portions 10 are spaced apart in the horizontal direction Y, with one low-density portion 7 located between them. In the napkin 1, the low-density portion 7 is located on the vertical center line CL1, and this low-density portion 7 is referred to as a central low-density portion 71. The remaining two low-density sections 7 are located on either side of a group G consisting of two high-density sections 10 and a central low-density section 71 located between them. The two low-density sections 7 are referred to as a left low-density section 72L and a right low-density section 72R, respectively. When there is no need to distinguish between the central low-density portion 71, the left low-density portion 72L, and the right low-density portion 72R, they are simply referred to as the low-density portion 7.

[0035] In the absorbent core 4, in a plan view, both of the two high density portions 10 are located inward in the lateral direction Y of the ends (referred to as side ends) 44s of the absorbent core 4 in the lateral direction Y. In other words, in the absorbent core 4, the two high density portions 10 are located closer to the center in the lateral direction Y.

[0036] In the absorbent core 4, group G is located across both the central region 8 and the side regions 9. At least a portion of each of the two high-density regions 10 constituting group G is located in the central region 8. In the absorbent core 4, as shown in Figures 2 and 3, in a plan view, the two high-density regions 10 are each located across both the central region 8 and the side regions 9, and the central low-density region 71 is located in the central region 8. Meanwhile, the left-side low-density region 72L and the right-side low-density region 72R are located in the side regions 9. In the center-high central region 44C, no high-density region is located near the side end portions 44s, but rather a low-density region is located therein.

[0037] ((adjacent to junior and senior high school)) As shown in Figures 1 and 3, in the intermediate region 6 of the absorbent core 4, the mid-high adjacent portion 45 is a block portion defined by the front mid-high boundary groove portion 42F and the front boundary horizontal groove portion 41F, and the rear mid-high boundary groove portion 42R and the rear boundary horizontal groove portion 41R. The crown adjacent portion 45 is an area that is thinner in thickness direction Z and has a lower basis weight than the crown portion 44 . In plan view, the crown adjacent portion 45 has a right-angled triangular shape. The two front adjacent crown portions 45 are located in front of the crown central portion 44C. The two front adjacent crown portions 45 are located on both sides in the lateral direction Y of the front convex portion 44F, sandwiching it therebetween. The two rear adjacent crown portions 45 are located behind the crown central portion 44C. The two rear adjacent crown portions 45 are located on both sides in the lateral direction Y of the rear convex portion 44R, sandwiching it therebetween. In a plan view of the absorbent core 4, the overall external shape of the four adjacent domed portions 45 and the domed portion 44 combined together has a rectangular shape.

[0038] ((Front and rear high-middle boundary grooves)) As shown in Figure 3, in the intermediate region 6 of the absorbent core 4, the front mid-high boundary groove portion 42F and the rear mid-high boundary groove portion 42R are regions that are thinner in thickness direction Z and have a lower basis weight than the mid-high portion 44 and the mid-high adjacent portion 45. In plan view, the front high-center boundary groove 42F has an inverted V shape, and the rear high-center boundary groove 42R has a V shape. Both the front high-center boundary groove 42F and the rear high-center boundary groove 42R are grooves that extend continuously across the entire width in the lateral direction Y.

[0039] (Configuration of the first area) As shown in FIGS. 1 and 3, in the absorbent core 4, the first region 11 is a region located in front of the intermediate region 6 in the longitudinal direction X, where the central peak 44 is located. In the absorbent core 4, the first region 11 has a front boundary lateral groove portion 41F, a front groove portion 47, and a front block portion .

[0040] ((Anterior boundary lateral groove)) As shown in Figure 3, in the first region 11 of the absorbent core 4, the front boundary horizontal groove portion 41F is an area that is thinner in the thickness direction Z and has a lower basis weight than the centrally elevated adjacent portion 45 and the front block portion 46 located in the front. The front boundary lateral groove 41F is a groove that extends parallel to the lateral direction Y and continuously across the entire width of the absorbent core 4 in the lateral direction Y. The front boundary lateral groove 41F is located at the boundary between the first region 11 and the intermediate region 6.

[0041] ((Front groove)) 3, the front groove 47 is a groove that defines an area in front of the front boundary horizontal groove 41F of the absorbent core 4. In the first region 11 of the absorbent core 4, the front groove 47 is an area that is thinner in the thickness direction Z and has a lower basis weight than the front block portion 46. The front grooves 47 are provided along the longitudinal direction X and the lateral direction Y. Of the front grooves 47, the front grooves extending in the longitudinal direction X are referred to as front longitudinal grooves 47X, and the front grooves extending in the lateral direction Y are referred to as front lateral grooves 47Y. When there is no need to particularly distinguish between the front longitudinal grooves 47X and the front lateral grooves 47Y, they are referred to as the front grooves 47. 1 and 3, the first region 11 of the absorbent core 4 is provided with one front lateral groove 47Y extending continuously across the entire width of the absorbent core 4 in the lateral direction Y and five front longitudinal grooves 47X extending continuously along the longitudinal direction X. The front lateral groove 47Y and the front longitudinal grooves 47X are arranged in a lattice pattern.

[0042] ((Front block part)) 1 and 3, in the first region 11 of the absorbent core 4, the front block portions 46 are block portions defined by the front groove portions 47 and the front boundary horizontal groove portions 41F. In the example shown in the figures, ten substantially rectangular front block portions 46 and two substantially fan-shaped front block portions 46 are located in the first region 11.

[0043] (Configuration of the second area) As shown in FIGS. 1 and 3, in the absorbent core 4, the second region 12 is a region located behind the intermediate region 6 in the longitudinal direction X, where the central peak 44 is located. In the absorbent core 4, the second region 12 has a rear boundary lateral groove portion 41R, a rear groove portion 49, and a rear block portion .

[0044] ((Posterior boundary lateral groove)) As shown in FIG. 3, in the second region 12 of the absorbent core 4, the rear boundary lateral groove portion 41R is an area that is thinner in the thickness direction Z and has a lower basis weight than the crown adjacent portion 45 and the rear block portion 48. The rear boundary lateral groove 41R is a groove that extends parallel to the lateral direction Y and continuously across the entire width of the absorbent core 4 in the lateral direction Y. The rear boundary lateral groove 41R is located at the boundary between the second region 12 and the intermediate region 6.

[0045] ((back groove)) 3, the rear groove 49 is a groove that defines a region rearward of the rear boundary horizontal groove 41R of the absorbent core 4. In the second region 12 of the absorbent core 4, the rear groove 49 is an area that is thinner in the thickness direction Z and has a lower basis weight than the rear block portion 48. The rear groove portions 49 are provided along the longitudinal direction X and the lateral direction Y. Of the rear groove portions 49, the rear groove portions extending in the longitudinal direction X are referred to as rear longitudinal groove portions 49X, and the rear groove portions extending in the lateral direction Y are referred to as rear lateral groove portions 49Y. When there is no need to particularly distinguish between the rear longitudinal groove portions 49X and the rear lateral groove portions 49Y, they are referred to as rear groove portions 49. 1 and 3, the second region 12 of the absorbent core 4 is provided with four rear horizontal grooves 49Y that extend continuously across the entire width of the absorbent core 4 in the horizontal direction Y and five rear vertical grooves 49X that extend continuously along the vertical direction X. The rear horizontal grooves 49Y and the rear vertical grooves 49X are arranged in a lattice pattern.

[0046] ((rear block part)) 1 and 3, in the second region 12 of the absorbent core 4, the rear block portions 48 are block portions defined by the rear groove portions 49 and the rear boundary horizontal groove portions 41R. In the example shown in the figures, the second region 12 includes 28 substantially rectangular rear block portions 48 and two substantially fan-shaped rear block portions 48.

[0047] [Absorbent core manufacturing method] For example, a fiber assembly mainly composed of fibers (water-absorbent fibers) such as wood pulp, or a fiber assembly containing particulate water-absorbent polymer, can be used as the absorbent core 4. The absorbent core 4 mainly composed of such a fiber assembly can be produced by producing a pre-press absorbent core using a known fiber stacking device equipped with a rotary drum, and then pressing the pre-press absorbent core using a press device. The pre-press absorbent core is manufactured so that the thickness of the high-density portion in the center portion is greater than the thickness of the low-density portion. Then, by pressing the pre-press absorbent core of this type in the thickness direction Z using a press device so that the thickness of the high-density portion is the same as the thickness of the low-density portion, it is possible to manufacture an absorbent core 4 having a center portion 44 with two regions (high-density portion 10 and low-density portion 7) that have different pulp fiber densities but the same thickness. When the napkin 1 uses an absorbent body in which an absorbent core is covered with a core wrap sheet, the pressing process using a press device may be carried out, for example, with the absorbent core still covered with the core wrap sheet before pressing.

[0048] [Action and effect] In the napkin 1, the absorbent core 4 has a central peak 44 having multiple high-density sections 10 and multiple low-density sections 7 that are the same thickness but have different pulp fiber densities, which improves the liquid absorption rate in the absorbent core 4, allows the liquid to be quickly diffused and retained, and makes it easier to maintain its shape. This effectively suppresses side leakage, resulting in a napkin 1 that is more comfortable to wear. The mechanism is explained below.

[0049] Here, the low density portion 7 tends to have a faster liquid absorption rate than the high density portion 10. In the napkin 1, the low-density portion 7 is provided in the central portion 44 of the absorbent core 4, so that liquid from the wearer is quickly absorbed by the absorbent core 4, and the liquid absorbed in the low-density portion 7 easily migrates to the high-density portion 10 due to the pulp fiber density gradient between the low-density portion 7 and the high-density portion 10. Since the high-density portion 10 extends in the longitudinal direction X, the liquid that migrates to the high-density portion 10 is quickly diffused and retained in the longitudinal direction X within the high-density portion 10. By diffusing the liquid in the longitudinal direction X using the high-density portion 10, the liquid absorption performance of the central portion 44, which is located across the entire width in the transverse direction Y in the excretory-part-facing region C, has a wide absorbent area, and has higher liquid retention than the surrounding area, can be effectively utilized widely in the plane direction. In other words, the in-plane utilization efficiency of the liquid absorption performance of the central portion 44 can be improved. Therefore, even if liquid is continuously supplied to the napkin 1, the high-density portions 10 and low-density portions 7 extending in the longitudinal direction X allow the liquid to be quickly diffused in the plane direction at the center-height portions 44, and the high-density portions 10 extending in the longitudinal direction X also promote the diffusion of liquid in the longitudinal direction X, thereby effectively suppressing side leakage. Furthermore, even if the napkin 1 is displaced from its appropriate position in the longitudinal direction X when worn, the high-density portions 10 extending in the longitudinal direction X can diffuse liquid in the longitudinal direction X, so the liquid absorption performance of the center-height portions 44 can be effectively utilized in the plane direction. In addition, by providing the high density portion 10, the amount of liquid held in the absorbent core 4 can be increased, and the amount of liquid that returns to the wearer due to the force applied by the wearer after being absorbed into the absorbent core 4 can be reduced. Furthermore, in the absorbent core 4 of the napkin 1, the high-density portions 10 and the low-density portions 7 have the same thickness in the center-height portion 44, which makes it easier to maintain the shape of the absorbent core. That is, by making the high-density portions 10 and the low-density portions 7 the same thickness, even when a force is applied inward in the lateral direction Y from both legs of the wearer when wearing the napkin, the shape of the absorbent core 4 is more easily maintained than in a configuration in which the low-density portions are thinner than the high-density portions, and this reduces the discomfort caused by the absorbent core being crushed and undergoing undesirable deformation, improving wearing comfort.

[0050] Furthermore, in the absorbent core 4, the mid-height portion 44 has a plurality of high-density portions 10 and a plurality of low-density portions 7, so that in a planar view, the mid-height portion 44 has low-density portions 7, high-density portions 10, low-density portions 7, and high-density portions 10 arranged in this order from one side to the other along the lateral direction Y. With this configuration, even if the napkin 1 is worn displaced in the lateral direction Y from the appropriate position, at least a portion of the low-density portions 7, which have a faster liquid absorption rate than the high-density portions 10, is likely to be positioned opposite the wearer's excretory area. Therefore, even if the absorbent core 4 is worn displaced in the lateral direction Y, the presence of the low-density portions 7 allows for rapid liquid absorption, liquid migration from the low-density portions 7 to the high-density portions 10 positioned adjacent to the low-density portions 7, and rapid liquid diffusion in the longitudinal direction X in the high-density portions 10, thereby effectively suppressing side leakage.

[0051] It is more preferable that one of the plurality of low-density regions 7 is located in the central region 8 of the absorbent core 4, which faces the excretory region of the wearer when worn in a plan view and is more likely to receive a larger amount of liquid. In the napkin 1, the central low-density region 71 is located in the central region 8. With this configuration, the absorbent core 4 can absorb liquid better when worn, and liquid leakage can be further suppressed. Furthermore, by sandwiching the central low-density section 71 located in the central region 8 of the absorbent core 4 and placing the high-density sections 10 on either side of it in the lateral direction Y, the liquid absorbed in the central low-density section 71 and transferred to the high-density section 10 is blocked by the high-density section 10, making it less likely to transfer further outward in the lateral direction Y than the group G, thereby further suppressing lateral leakage.

[0052] Furthermore, the multiple high-density portions 10 are preferably located more inward in the lateral direction Y than the side end portions 44s of the center portion 44C. In other words, in the center portion 44C, it is preferable that the high-density portions 10 are located closer to the center in the lateral direction Y, and that no high-density portions exist near the side end portions 44s, but that low-density portions exist near the side end portions 44s. With this configuration, the pair of high-density portions 10 in the absorbent core 4 can slow the diffusion of liquid outside the lateral direction Y beyond the pair of high-density portions 10, thereby more effectively suppressing lateral leakage.

[0053] Also, as shown in Figures 2 and 3, in the absorbent core 4, the mid-height portion 44 may be composed of two high-density portions 10 and three low-density portions, and one low-density portion 7 (central low-density portion 71) may be located between two high-density portions 10 spaced apart in the horizontal direction Y, with the remaining two low-density portions 7 (left-side low-density portion 72L and right-side low-density portion 72R) located on both sides of the group G in the horizontal direction Y. With this configuration, no high-density portions 10 are present near both side ends 44s of the center-height central portion 44C located across the entire width in the lateral direction Y, but the low-density portions 7 are present. By configuring the areas near both side ends 44s of the center-height central portion 44C, which are likely to come into contact with the base of the wearer's legs when worn, with low-density portions 7 that are lower in rigidity than the high-density portions 10, the napkin 1 is imparted with flexibility near both side ends 44s of the center-height central portion 44C, making it softer against the skin and further improving wearing comfort. Furthermore, with the above-described configuration, the force exerted by the wearer toward the inside in the lateral direction Y at the central peak 44 of the absorbent core 4 is buffered by the relatively low rigidity left low-density portion 72L and right low-density portion 72R. As a result, undesirable deformation is less likely to occur in the region of group G located more inward in the lateral direction Y than the left low-density portion 72L and right low-density portion 72R. This maintains close contact between the napkin 1 and the wearer's excretory area, further suppressing side leakage.

[0054] As shown in Figures 1 and 3, in plan view, it is preferable that the central portion 44 has a front convex portion 44F and a rear convex portion 44R at the front and rear, respectively, as second portions whose width decreases outward in the longitudinal direction X. With this configuration, in the absorbent core 4 of the napkin 1, in the front part of the intermediate region 6, the width of the center-high portion 44 gradually narrows toward the first region 11, while the width of the center-high portion adjacent portion 45, which has a lower basis weight and thickness than the center-high portion 44, gradually widens. In the rear part of the intermediate region 6, the width of the center-high portion 44 gradually narrows toward the second region 12, while the width of the center-high portion adjacent portion 45, which has a lower basis weight and thickness than the center-high portion 44, gradually widens. The crowned portion 44 has higher rigidity and is less likely to deform due to external forces than the crowned portion adjacent portion 45. On the other hand, the crowned portion adjacent portion 45 has a relatively low basis weight and is therefore more likely to deform due to external forces and is therefore more likely to cushion external forces. That is, in the intermediate region 6 of the absorbent core 4, the more deformable regions gradually expand from the crown center 44C of the intermediate region 6 toward the first region 11 and the second region 12. In other words, in the front intermediate second region 62F, the more deformable region expands toward the front, and in the rear intermediate second region 62R, the more deformable region expands toward the rear. By expanding the more deformable regions in this manner, external forces are more easily absorbed, and when a force is applied to the intermediate region 6 from the wearer toward the inside in the lateral direction Y, the force is more easily absorbed toward the front and rear, effectively suppressing the effects of deformation due to external forces in the intermediate region 6 from propagating to the first region 11 and the second region 12.

[0055] Furthermore, it is preferable that the foremost part of the front convex portion 44F and the rearmost part of the rear convex portion 44R are located in the central region 8. By shaping the center portion 44 of the absorbent core 4 in this way, the portion of the center portion 44 located in the central region 8 is longer in the longitudinal direction X than the portions located in the lateral regions 9. As a result, even if the napkin 1 is displaced in the longitudinal direction X from its appropriate position when worn, the center portion 44 is reliably positioned opposite the wearer's excretory area, so that the low-density portions 7 quickly absorb liquid and the high-density portions 10 quickly diffuse liquid in the longitudinal direction X, thereby effectively suppressing side leakage. Furthermore, by forming the central portion 44 of the absorbent core 4 in the above-described shape, liquid that has diffused in the vertical direction X in the central portion 44 is more likely to migrate to the front and rear and be collected in the central region 8, further suppressing side leakage.

[0056] The front convex portion 44F and the rear convex portion 44R are defined and formed by an inverted V-shaped front high-center boundary groove portion 42F and a V-shaped rear high-center boundary groove portion 42R, respectively. Because the front and rear mid-high boundary grooves 42F and 42R are formed across the entire width of the absorbent core 4 in the lateral direction Y, longitudinal wrinkles are unlikely to form in the portions of the napkin 1 corresponding to the front portion (where the front convex portion 44F is located) and the rear portion (where the rear convex portion 44R is located) of the intermediate region 6 in response to a force acting inward in the lateral direction Y from the wearer's legs. In addition, when an external force is applied, the intermediate region 6 of the absorbent core 4 is likely to deform with the front mid-high boundary groove 42F and the V-shaped rear mid-high boundary groove 42R as the deformation starting points. Therefore, when worn, the intermediate region 6 is likely to deform along the shape of the body, providing a better three-dimensional fit and further suppressing side leakage.

[0057] In the napkin 1, an example has been given in which the high-density portion 10 extends in the longitudinal direction X, but the high-density portion may also be formed by a plurality of high-density elements intermittently positioned in the longitudinal direction X. In other words, a portion having a lower density than the high-density elements may be positioned between adjacent high-density elements in the longitudinal direction X, and the plurality of high-density elements may be regarded as a single high-density portion extending in the longitudinal direction X as a whole. In this case, from the viewpoint of good liquid diffusion in the longitudinal direction X in the high-density portion 10, the length in the longitudinal direction X of the low-density portion positioned between adjacent high-density elements in the longitudinal direction X is preferably 200 mm or less. However, as shown in Figure 3, it is more preferable that the high-density portion 10 extends continuously in the longitudinal direction X. By making the high-density portion 10 extend continuously in the longitudinal direction X, the liquid-drawing force of the high-density portion 10 can be further increased, the liquid can be more quickly diffused in the longitudinal direction X, and side leakage can be further suppressed. Furthermore, the rigidity of the excretory portion-facing region C can be ensured, and undesirable deformation can be suppressed, thereby maintaining good liquid absorption performance in the central-high portion 44.

[0058] 3, in the absorbent core 4, it is more preferable that the high-density portions 10 extend continuously in the longitudinal direction X, and the low-density portions 7 extend continuously in the longitudinal direction X. By having the low-density portions 7 extend continuously in the longitudinal direction X, even if the absorbent core 4 is misaligned in the transverse direction Y from the appropriate position when worn, the low-density portions 7 allow for rapid absorption of liquid and the high-density portions 10 allow for rapid diffusion of liquid in the longitudinal direction X, thereby effectively suppressing side leakage.

[0059] In the napkin 1, the high-density portion 10 extends in the longitudinal direction X over the entire length of the central portion 44 from the front end 44a to the rear end 44b of the central portion 44, but the high-density portion 10 does not have to extend to at least one of the front end 44a and the rear end 44b. In this case, the length of the high-density portion 10 in the longitudinal direction X is preferably 50 mm or more from the viewpoint of liquid diffusion in the longitudinal direction X and suppression of side leakage. Even in such a configuration, since the high-density portion 10 extends in the longitudinal direction X, liquid can be quickly transferred in the longitudinal direction X in the high-density portion 10, making it possible to widely and effectively utilize the liquid absorption performance of the central portion 44 and effectively suppress side leakage. However, from the viewpoint of more reliably suppressing lateral leakage by diffusing liquid in the vertical direction X even if the napkin 1 is misaligned in the vertical direction X relative to the wearer, and from the viewpoint of more widely utilizing the liquid absorption performance of the central portion 44 within the plane, it is more preferable that the high-density portion 10 extend in the vertical direction X over the entire length of the central portion 44 from the front end 44a to the rear end 44b of the central portion 44.

[0060] In order to effectively suppress side leakage, the low-density portion 7 preferably extends continuously in the longitudinal direction X over the entire length of the center portion 44 from the front end portion 44a to the rear end portion 44b. With this configuration, even if the napkin 1 is displaced in the longitudinal direction X from the appropriate position, the low-density portion 7 allows for rapid absorption of liquid.

[0061] From the viewpoint of improving flexibility and fit, and of facilitating rapid liquid absorption due to the presence of low-density portions, it is preferable that in the absorbent core 4, the width v of the high-density portion 10 is narrower than the width u of the central low-density portion 71, and the width w of the left-side low-density portion 72L and the right-side low-density portion 72R, as shown in FIG. With this configuration, the proportion of the high-density portion 10 in the central portion 44 can be reduced, and the rigidity of the entire central portion 44 can be reduced, allowing the absorbent core 4 to easily deform along the shape of the wearer's body, improving fit. Furthermore, even if misalignment occurs in the lateral direction Y when the napkin 1 is worn, the low-density portion 7 is more likely to be positioned opposite the wearer's excretory area, allowing for rapid absorption of liquid due to the presence of the low-density portion.

[0062] From the viewpoint of improving flexibility and fit, it is preferable that the absorbent core 4 has grooves in each of the first region 11 and the second region 12, as shown in FIGS. The first region 11 has, as grooves, a front longitudinal groove 47X extending in the longitudinal direction X, a front lateral groove 47Y extending in the lateral direction Y, and a front boundary lateral groove 41F extending in the lateral direction Y. The second region 12 has, as grooves, a rear longitudinal groove 49X extending in the longitudinal direction X, a rear lateral groove 49Y extending in the lateral direction Y, and a rear boundary lateral groove 41R extending in the lateral direction Y. In the absorbent core 4, by providing a front boundary horizontal groove portion 41F and a rear boundary horizontal groove portion 41R that extend across the entire width in the lateral direction Y, the effects of deformation in each of the first region 11 and the second region 12 can be less likely to extend to the middle region 6, making it easier to maintain the shape and liquid absorption performance of the middle-height portion 44 in good condition. Furthermore, by providing the first region 11 and the second region 12 with a plurality of front grooves 47 and rear grooves 49 extending in the longitudinal direction X and the lateral direction Y, the first region 11 and the second region 12 can more easily deform to fit the shape of the wearer's body, with the grooves serving as deformation starting points, thereby improving fit.

[0063] 4, it is preferable that the rear groove portion 49 is present on an extension of the central low-density portion 71 in the longitudinal direction X. The rear groove portion 49, located rearward in the longitudinal direction X of the central low-density portion 71, is easily deformed to protrude toward the wearer's intergluteal cleft, and when excreted fluid diffuses from the central low-density portion 71 not only toward the high-density portion 10 but also rearward in the longitudinal direction X, the protruding portion can receive the fluid, making it easier to prevent fluid leakage from the rear end portion.

[0064] [Supplementary explanation of this embodiment] (Example dimensions of each absorbent core configuration) 1 and 4, examples of dimensions of each component of the absorbent core 4 will be described below. Note that the dimensions of each component of the absorbent core can be set appropriately depending on, for example, the shape and size of the napkin, and are not limited to the numerical values ​​described below.

[0065] In the napkin 1 of this embodiment, the groove width at the bottom of each groove formed in the absorbent core 4 is approximately the same as the groove width at the opening of the groove. The bottom of the groove is positioned approximately parallel to the non-skin-contact side of the absorbent core. The side of the groove forming the groove is approximately perpendicular to the bottom. The "groove width" described below refers to the width at the opening of the groove, and the groove thickness described below refers to the thickness of the bottom portion that forms the groove. Here, the grooves are described as having a generally rectangular cross section perpendicular to the longitudinal direction of the grooves, but are not limited to this. For example, the grooves may have a V-shaped or trapezoidal cross section with tapered sides that widen from the bottom toward the opening. Even in such cases, the absorbent core 4 will have a lower basis weight and lower rigidity in the areas where the grooves are formed compared to areas where no grooves are formed. For example, in the case of grooves having a V-shaped or trapezoidal cross section, the "groove width" refers to the width at the opening. The groove width and thickness of the groove can be measured by cutting the groove in a direction perpendicular to the direction in which the groove extends and taking a photograph of the cut surface.

[0066] The absorbent core 4 has a constant width along the longitudinal direction X. As an example, the width a of the absorbent core 4 is 73 mm.

[0067] In the absorbent core 4, the total length L2 in the longitudinal direction X of the center portion 44 is preferably 25% or more, more preferably 30% or more, and preferably 90% or less, more preferably 75% or less, and also preferably 25% or more and 90% or less, more preferably 30% or more and 75% or less of the total length L1 in the longitudinal direction X of the absorbent core 4. The overall length L2 of the central portion 44 in the longitudinal direction X corresponds to the length of the intermediate region 6 of the absorbent core 4 in the longitudinal direction X.

[0068] The total length L3 in the vertical direction X of the center portion 44C constituting part of the center portion 44 is preferably 20% or more, more preferably 30% or more, and preferably 80% or less, more preferably 70% or less of the total length L2 of the center portion 44, and is preferably 20% or more and 80% or less, more preferably 30% or more and 70% or less. The overall length L3 of the center portion 44C in the longitudinal direction X corresponds to the length of the intermediate first region 61 in the longitudinal direction X.

[0069] The total length L4 of each of the front convex portion 44F and the rear convex portion 44R that constitute part of the center portion 44 is preferably 5% or more, more preferably 10% or more, and preferably 50% or less, more preferably 30% or less of the total length L2 of the center portion 44, and is preferably 5% or more and 50% or less, more preferably 10% or more and 30% or less. The overall length L4 of each of the front convex portion 44F and the rear convex portion 44R corresponds to the length in the longitudinal direction X of each of the front intermediate second region 62F and the rear intermediate second region 62R.

[0070] For example, the total length L1 of the absorbent core 4 in the longitudinal direction X is 270 mm. The total length L2 of the central portion 44 in the longitudinal direction X is 120 mm. The overall length L3 of the center portion 44C in the vertical direction X is 80 mm. The total length L4 in the longitudinal direction X of each of the front convex portion 44F and the rear convex portion 44R is 20 mm.

[0071] As an example, the dimension b of the first region 11 in the vertical direction X is 33 mm. The dimension d of the second region 12 in the longitudinal direction X is 117 mm.

[0072] As an example, the groove width e of the front boundary lateral groove portion 41F is 2 mm. The groove width i of the front lateral groove 47Y is 2 mm, and the groove width j of the front vertical groove 47X is 1.5 mm. The dimension g of the front block portion 46 in the longitudinal direction X is 18 mm, and the dimension h in the lateral direction Y is 9.5 mm. The groove width f of the rear boundary lateral groove portion 41R is 2 mm. The groove width n of the rear lateral groove portion 49Y is 2 mm, and the groove width o of the rear vertical groove portion 49X is 1.5 mm. The dimension k of the rear block portion 48 in the vertical direction X is 18 mm, and the dimension m in the horizontal direction Y is 9.5 mm. Each of the four adjacent convex portions 45 has a dimension r in the vertical direction X of 17 mm and a dimension s in the horizontal direction Y of 20 mm.

[0073] In the napkin 1, the groove width p of the front central-high boundary groove portion 42F and the rear central-high boundary groove portion 42R in the absorbent core 4 is preferably 0.1 mm or more, more preferably 0.5 mm or more, from the viewpoint of improving flexibility and fit, and is also preferably 5.0 mm or less, more preferably 3.0 mm or less, and is also preferably 0.1 mm or more and 5.0 mm or less, more preferably 0.5 mm or more and 3.0 mm or less. As an example, the groove width p of the front and rear median-high boundary groove portions 42F and 42R is 1.9 mm.

[0074] In a plan view, the front convex portion 44F and the rear convex portion 44R are in a line-symmetric relationship. Taking the front convex portion 44F as an example, the angle α formed between each of the two straight lines constituting the front end portion 44a and the vertical center line CL1 is preferably 20° or more, more preferably 30° or more, and preferably 75° or less, more preferably 60° or less, from the viewpoint of improving fit to the body shape and followability to movement, and is specifically preferably 20° or more and 75° or less, more preferably 30° or more and 60° or less. The rear convex portion 44R is similar to the front convex portion 44F. As an example, the angle α is 28°.

[0075] From the viewpoint of improving the flexibility and fit of the napkin 1 while realizing good liquid diffusion in the longitudinal direction X, and from the viewpoint of enabling rapid liquid absorption due to the presence of the low-density portions 7 even if the napkin 1 is misaligned in the lateral direction Y when worn, the width v of the high-density portions 10 is preferably 5 mm or more, more preferably 7 mm or more, and also preferably 12 mm or less, more preferably 10 mm or less, and also preferably 5 mm or more and 12 mm or less, more preferably 7 mm or more and 10 mm or less. As an example, the width v of the high density portion 10 is 9.5 mm.

[0076] Furthermore, from the viewpoint of improving flexibility and fit while realizing good liquid diffusion in the longitudinal direction X, the occupancy rate of the high-density portion 10 in the transverse direction Y at the center-high portion 44C is preferably 30% or more, more preferably 40% or more, and is preferably 85% or less, more preferably 70% or less, and is preferably 30% or more and 85% or less, more preferably 40% or more and 70% or less. As an example, the occupancy rate of the high density portion 10 in the lateral direction Y in the central part 44C of the convex part is 40%. In the napkin 1 of this embodiment, the absorbent core 4 is formed to have a uniform width along the longitudinal direction X, so the occupancy rate of the high-density portions 10 in the transverse direction Y at the center portion 44C can be calculated as 2v / a×100(%), where v represents the width of one high-density portion 10 and a represents the width of the absorbent core 4. Furthermore, if the absorbent core 4 does not have the same width along the longitudinal direction X, the width of the smallest part in the central part 44C is taken as a', and the occupancy rate of the high density part 10 in the transverse direction Y in the central part 44C can be calculated as 2v / a' × 100 (%).

[0077] It is preferable that the width u of the central low-density portion 71 and the width w of the left low-density portion 72L and the right low-density portion 72R are wider than the width v of the high-density portion 10.

[0078] From the viewpoint of improving flexibility and fit, and of enabling rapid absorption of liquid due to the presence of the central low-density portion 71 even if the napkin 1 is misaligned in the lateral direction Y when worn, the width u of the central low-density portion 71 is preferably 7 mm or more, more preferably 9 mm or more, and also preferably 15 mm or less, more preferably 12 mm or less, and also preferably 7 mm or more and 15 mm or less, more preferably 9 mm or more and 12 mm or less. As an example, the width u of the central low-density portion 71 is 11 mm.

[0079] From the viewpoint of further suppressing side leakage, the plurality of high-density portions 10 are preferably located more inward in the lateral direction Y than the side end portions 44s of the center-protruding portion 44C. In other words, it is preferable that the left low-density portion 72L and the right low-density portion 72R are located on both sides of the pair of high-density portions 10, sandwiching them therebetween. From the viewpoint of improving wearing comfort and suppressing side leakage, the width w of the left low-density portion 72L and the right low-density portion 72R is preferably 8 mm or more, more preferably 9 mm or more, and is preferably 20 mm or less, more preferably 16 mm or less, and is preferably 8 mm or more and 20 mm or less, more preferably 9 mm or more and 16 mm or less. As an example, the width w of the left low-density portion 72L and the right low-density portion 72R is 13 mm.

[0080] From the viewpoint of further suppressing lateral leakage, it is preferable that the multiple high-density portions 10 are located more inward in the horizontal direction Y than the side end portions 44s of the center portion 44C, in other words, closer to the center in the horizontal direction Y, and the occupancy rate of the group G in the horizontal direction Y at the center portion 44C is preferably 15% or more, more preferably 20% or more, and also preferably 60% or less, more preferably 40% or less, and also preferably 15% or more and 60% or less, more preferably 20% or more and 40% or less. As an example, the width t of the group G is 30 mm, and the occupancy rate of the group G in the horizontal direction Y at the center of the center portion 44C is 40%. In this embodiment, since the absorbent core 4 is formed to have a uniform width along the longitudinal direction X, the occupancy rate of the group G in the center portion 44C can be calculated by t / a × 100 (%), where t is the width of the group G and a is the width of the absorbent core 4. Furthermore, if the absorbent core 4 does not have the same width along the longitudinal direction X, the width of the smallest part in the central part 44C is defined as a', and the occupancy rate of the group G in the central part 44C can be calculated as t / a' × 100(%).

[0081] (Examples of thickness for each configuration) The thickness of each component in the absorbent core 4 will be explained below, but is not limited to these numerical values.

[0082] ((Thickness of the middle part)) In the napkin 1, the thickness of the mid-height portion 44 in the absorbent core 4 is preferably at least 120% (i.e., 1.2 times) and more preferably at least 140% of the thickness of the front block portion 46 in the first region 11 and the rear block portion 48 in the second region 12, from the viewpoint of protruding the mid-height portion 44 toward the skin and improving the liquid absorbency of the absorbent core 4 in the excretory-facing region C of the absorbent core 4, as shown in Figure 3, and is also preferably at most 700%, more preferably at most 500%.Furthermore, from the viewpoint of reducing the ability to conform to the body and discomfort when worn, the thickness is preferably at least 120% and at most 700%, more preferably at most 140% and at most 500%.

[0083] Furthermore, the difference between the thickness of the central height portion 44 and the thickness of the front block portion 46 and the rear block portion 48 (the former - the latter) is preferably 1.0 mm or more, more preferably 2.0 mm or more, and is preferably 8.0 mm or less, more preferably 6.0 mm or less, and is preferably 1.0 mm or more and 8.0 mm or less, more preferably 2.0 mm or more and 6.0 mm or less. The above-described configuration is particularly effective when the raised portion 44 is provided in the excretory region C as in the napkin 1 of the above-described embodiment.

[0084] Specifically, the thickness of the central portion 44 is preferably 2.0 mm or more, more preferably 3.0 mm or more, and is preferably 10.0 mm or less, more preferably 7.0 mm or less, and is preferably 2.0 mm or more and 10.0 mm or less, more preferably 3.0 mm or more and 7.0 mm or less. As an example, the thickness of the crown 44 is 6.3 mm.

[0085] ((Thickness of the adjacent part of the cone)) In the napkin 1, the thickness of the center-high adjacent portion 45 in the absorbent core 4 is formed to be thicker than the thickness of the front center-high boundary groove portion 42F and the rear center-high boundary groove portion 42R, but thinner than the thickness of the center-high portion 44, as shown in FIG. From the viewpoint of adaptability to body movement, it is preferable that the thickness of the center-high adjacent portion 45 is equal to or thinner than the thickness of the front block portion 46 of the first region 11 and the rear block portion 48 of the second region 12. However, from the viewpoint of the strength of the absorbent core 4 when repeatedly deformed in response to body movement, the thickness of the center-high adjacent portion 45 may be thicker than the front block portion 46 and the rear block portion 48. The thickness of the convex portion 45 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and is preferably 10.0 mm or less, more preferably 7.0 mm or less, and is preferably 0.5 mm or more and 10.0 mm or less, more preferably 1.0 mm or more and 7.0 mm or less. As an example, the thickness of the crown adjacent portion 45 is 2.3 mm.

[0086] ((Thickness of the front block and rear block)) In the napkin 1, the thickness of the front block portion 46 and the rear block portion 48 in the absorbent core 4 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and is preferably 7.0 mm or less, more preferably 3.5 mm or less, and is preferably 0.5 mm or more and 7.0 mm or less, more preferably 1.0 mm or more and 3.5 mm or less. As an example, the thickness of the front block portion 46 and the rear block portion 48 is 2.3 mm.

[0087] ((thickness of groove)) In the napkin 1, in order to improve flexibility and fit, the thickness of the groove portions (front groove portion 47, rear groove portion 49, front boundary horizontal groove portion 41F, rear boundary horizontal groove portion 41R, front mid-high boundary groove portion 42F, rear mid-high boundary groove portion 42R) in the absorbent core 4 is formed thinner than the thickness of the mid-high portion 44, mid-high adjacent portion 45, front block portion 46 and rear block portion 48. The thickness of the groove is preferably 0.08 mm or more, more preferably 0.15 mm or more, and is preferably 7.0 mm or less, more preferably 3.5 mm or less, and is preferably 0.08 mm or more and 7.0 mm or less, more preferably 0.15 mm or more and 3.5 mm or less. As an example, the groove thickness is 1.5 mm.

[0088] ((Method for measuring the thickness of each component in an absorbent core)) The absorbent core is placed on a horizontal surface to avoid wrinkles or folds, and the measurement objects, namely, the center-high portion 44, the front block portion 46, the rear block portion 48, the center-high adjacent portion 45, and the groove portions (the front groove portion 47, the rear groove portion 49, the front boundary horizontal groove portion 41F, the rear boundary horizontal groove portion 41R, the front center-high boundary groove portion 42F, and the rear center-high boundary groove portion 42R), are cut out from the absorbent core 4. The cut-out measurement objects are then pressurized at a pressure of 5 kPa for 10 minutes, and measurements are taken immediately after removal. A 20 mm x 20 mm, 3 mm thick acrylic plate is placed in the center of the sample after removal, and the thickness of the sample is measured using a KEYENCE non-contact laser displacement meter (laser head LK-G30, displacement meter LK-GD500). When the size of the cut-out measurement object is small and difficult to measure using a non-contact laser displacement meter, the cross section of the cut measurement object may be observed and measured using, for example, a microscope (VHX-1000 manufactured by KEYENCE Corporation) at a magnification of 20 to 100 times.

[0089] (Basis weight of each component) The basis weight of each component of the absorbent core 4 of the napkin 1 will be explained below, but is not limited to these numerical values.

[0090] ((Basis weight in the middle and upper parts)) In the absorbent core 4, from the viewpoints of softness and fit, and of quickly diffusing liquid within the high-density portion 10, the basis weight of the high-density portion 10 of the central portion 44 is preferably 400 g / m 2 More preferably, 500 g / m 2 or more, and preferably 1800 g / m 2 or less, more preferably 1500 g / m 2 and preferably 400 g / m 2 More than 1800g / m 2 Less than 500 g / m 2 More than 1500g / m 2 The following is the result. As an example, the basis weight of the high density portion 10 is 600 g / m 2 is.

[0091] In the absorbent core 4, from the viewpoint of softness and fit, and from the viewpoint of rapid liquid absorption due to the presence of the low-density portion 7, the basis weight of the low-density portion 7 of the central peak portion 44 is preferably 300 g / m 2 More preferably, 400 g / m 2 or more, and preferably 1000 g / m 2 Less than 800 g / m 2 and preferably 300 g / m 2 More than 1000g / m 2 Less than 400 g / m 2 More than 800g / m 2 The following is the result. As an example, the basis weight of the low density portion 7 is 450 g / m 2 is.

[0092] ((Basis weight of adjacent part of convex part)) In the absorbent core 4, the center-height adjacent portion 45 is formed so that its basis weight is lower than that of the center-height portion 44 of the absorbent core 4 and higher than that of the front center-height boundary groove portion 42F and the rear center-height boundary groove portion 42R. Furthermore, from the viewpoint of adaptability to body movements, it is preferable that the basis weight of the center-high adjacent portion 45 is equal to or lower than the basis weight of the front block portion 46 and the rear block portion 48 . Furthermore, from the viewpoint of the strength of the absorbent core 4 when repeatedly deformed due to body movement, the central adjacent portion 45 may have a basis weight greater than that of the front block portion 46 and the rear block portion 48. The basis weight of the crown adjacent portion 45 is preferably 20 g / m 2 More preferably, 50 g / m 2 and preferably 800 g / m 2 Less than 700 g / m 2 and preferably 20 g / m 2 More than 800g / m 2 Less than 50 g / m 2 More than 700g / m 2 The following is the result. As an example, the basis weight of the convex portion 45 is 240 g / m 2 is.

[0093] ((Basis weight of front block part and rear block part)) In the napkin 1, the basis weight of the front block portion 46 of the first region 11 and the rear block portion 48 of the second region 12 in the absorbent core 4 is preferably 50 g / m 2 from the viewpoint of improving softness and fit while maintaining good liquid absorbency and the like. 2 More preferably, 100 g / m 2 or more, and preferably 1000 g / m 2 Less than 900 g / m 2 and preferably 50 g / m 2 More than 1000g / m 2 or less, more preferably 100 g / m 2 More than 900g / m 2 The following is the result. As an example, the basis weight of the front block portion 46 and the rear block portion 48 is 240 g / m 2 is.

[0094] ((Ground weight of groove)) In the napkin 1, in order to improve flexibility and fit, the basis weight of the groove portions (front groove portion 47, rear groove portion 49, front boundary horizontal groove portion 41F, rear boundary horizontal groove portion 41R, front mid-high boundary groove portion 42F, rear mid-high boundary groove portion 42R) in the absorbent core 4 is formed to be lower than the basis weight of the mid-high portion 44, and further lower than the basis weight of the mid-high adjacent portion 45, front block portion 46 and rear block portion 48. The basis weight of the groove is preferably 10 g / m 2 More preferably, 20 g / m 2 and preferably 350 g / m 2 or less, more preferably 250 g / m 2 Specifically, it is preferably 10 g / m or less. 2 More than 350g / m 2 Less than 20 g / m, more preferably 2 More than 250g / m 2 The following is the result. As an example, the basis weight of the groove is 100 g / m 2 is.

[0095] ((Method of measuring basis weight)) The basis weight of each of the measurement objects, namely, the center-high portion 44, the front block portion 46, the rear block portion 48, the center-high adjacent portion 45, and the groove portions (front groove portion 47, rear groove portion 49, front boundary horizontal groove portion 41F, rear boundary horizontal groove portion 41R, front center-high boundary groove portion 42F, and rear center-high boundary groove portion 42R), is calculated by dividing the weight of the measurement object in the target region cut out as described in the method for measuring the thickness of each portion of the absorbent core 4 above by the area of ​​the skin-facing surface of the measurement object. An electronic balance (A&D Electronic Balance GR-300, accuracy: four decimal places) is used to measure the weight. The average basis weight of five measurement objects for each portion is calculated as the basis weight.

[0096] (Pulp fiber density in high-density and low-density parts) In the absorbent core 4, in order to ensure good liquid migration from the low-density portion 7 to the high-density portion 10 due to the pulp fiber density gradient between the low-density portion 7 and the high-density portion 10, the pulp fiber density of the high-density portion 10 of the mid-high portion 44 is preferably 30% or more, more preferably 40% or more, and preferably 85% or less, more preferably 70% or less, of the pulp fiber density of the low-density portion 7, and is preferably 30% or more and 85% or less, more preferably 40% or more and 70% or less. As an example, for Napkin 1, it is 60%.

[0097] In the absorbent core 4, from the viewpoints of softness and fit and of quickly diffusing liquid within the high density portion 10, the pulp fiber density of the high density portion 10 of the central portion 44 is preferably 0.015 g / cm 3 More preferably, 0.020 g / cm 3 or more, and preferably 30 g / cm 3 or less, more preferably 25 g / cm 3 and preferably 0.015 g / cm 3 More than 30g / cm 3 or less, more preferably 0.020 g / cm 3 More than 25g / cm 3 The following is the result. As an example, the pulp fiber density of the high density portion 10 is 0.095 g / cm3 is.

[0098] In the absorbent core 4, from the viewpoint of softness and fit, and from the viewpoint of rapid liquid absorption due to the presence of the low-density portion 7, the pulp fiber density of the low-density portion 7 of the central-high portion 44 is preferably 0.010 g / cm 3 More preferably, 0.015 g / cm 3 and preferably 20 g / cm 3 or less, more preferably 15 g / cm 3 and preferably 0.010 g / cm 3 More than 20g / m 2 or less, more preferably 0.015 g / cm 3 More than 15g / cm 3 The following is the result. As an example, the pulp fiber density of the low density portion 7 is 0.071 g / cm 3 is.

[0099] ((Method for measuring pulp fiber density)) The pulp fiber density is calculated by dividing the basis weight of each measurement area of ​​the absorbent core 4 by the thickness. The basis weight and thickness can be measured by the measurement methods described above.

[0100] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the gist of the present invention.

[0101] For example, although the above embodiment has been described with reference to a sanitary napkin as an example of an absorbent article, the absorbent article of the present invention is not limited to this, and may be, for example, a diaper, a urine absorption pad, a panty liner, or the like.

[0102] In addition, in the above-described embodiment, an example was given of a configuration in which the central peak of the absorbent core protrudes toward the skin side, but the absorbent core may also be configured so that the central peak protrudes toward the non-skin side. [Explanation of symbols]

[0103] 1... Napkins (sanitary napkins, absorbent articles) 4...Absorbent core 6...middle area 7…Low density part 10...High density part 11...First area 12…Second area 44...Junior and Senior High School 44C...Central part of the middle and upper part (first part)

Claims

1. An absorbent article having an absorbent core and having a longitudinal direction corresponding to the front-to-back direction of a wearer and a lateral direction perpendicular to the longitudinal direction, The absorbent core is divided into a first region, an intermediate region, and a second region in the longitudinal direction, The absorbent core has a central region located in the center when the absorbent core is divided into three equal parts in the horizontal direction, and side regions located on both the left and right sides of the central region, the absorbent core has a central peak in the intermediate region that is thicker and has a higher basis weight than the first region and the second region; The crown portion includes a first region that extends across the entire width of the absorbent core in the lateral direction, The crowned portion has a plurality of high density portions extending in the vertical direction and a plurality of low density portions having a lower density than the high density portions and extending in the vertical direction, The high density portion and the low density portion have the same thickness, The high density portion and the low density portion have different basis weights, The plurality of high-density portions are each located inside both lateral end portions of the absorbent core, the crowned portion has a group formed by one of the low-density portions being located between two of the high-density portions, the group is located across the central region and both lateral regions, At least a portion of each of the two high-density portions forming the group is located in a central region. Absorbent articles.

2. The center portion has second portions at its front and rear, each of which has a width that decreases outward in the vertical direction in a plan view. The absorbent article of claim 1.

3. One of the plurality of low density portions is located in a lateral central region of the absorbent core in a plan view. The absorbent article according to claim 1 or 2.

4. In the central portion, the high density portion is provided continuously in the vertical direction. The absorbent article according to any one of claims 1 to 3.

5. In the crowned portion, the high density portion extends from the front end to the rear end of the crowned portion. The absorbent article of claim 4.

6. The plurality of high-density portions are located laterally inward of the end portions of the first portion of the central peak. The absorbent article according to any one of claims 1 to 5.

7. The crown portion has two high-density portions and three low-density portions, The group is formed by one low-density portion being located between two high-density portions, and the remaining two low-density portions are located on both sides of the group. The absorbent article according to any one of claims 1 to 6.

8. The high density portion has a narrower width than the low density portion. The absorbent article according to any one of claims 1 to 7.

9. the first region and the second region have low basis weight groove portions extending in the machine direction and the cross direction, and a plurality of block portions partitioned by the low basis weight groove portions, In the absorbent core, a bottom portion forming the low basis weight groove portion has a basis weight lower and a thickness smaller than that of the block portion. The absorbent article according to any one of claims 1 to 8.

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