CN109803619B

CN109803619B - Absorbent body, method for producing same, and absorbent article

Info

Publication number: CN109803619B
Application number: CN201680089752.7A
Authority: CN
Inventors: 山口正史; 合田裕树; 佃淳志; 多田浩亚希
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2016-11-30
Filing date: 2016-11-30
Publication date: 2022-04-19
Anticipated expiration: 2036-11-30
Also published as: WO2018100704A1; CN109803619A; JPWO2018100704A1; JP6755334B2

Abstract

The invention discloses an absorbent body, an absorbent article comprising the absorbent body, and a method for producing the absorbent body, wherein the absorbent body (100) comprises a super absorbent polymer containing hydrophilic fibers and particlesAnd a core covering layer (120) covering the absorbent core, and having a longitudinal direction, a width direction and a thickness direction, and a skin-side surface and a non-skin-side surface, the absorbent body comprising a superabsorbent polymer content of 40 to 85 mass% and a non-skin-side surface, the absorbent body having a superabsorbent polymer content of 0.15g/cm³And at least 1 region having an average density of the above, the at least 1 region having a plurality of scattered concave portions and convex portions located between the plurality of concave portions on one surface or both surfaces of the skin-side surface and the non-skin-side surface, wherein in a portion of any two adjacent concave portions and convex portions located between the any two adjacent concave portions in the longitudinal direction of the absorbent body in a plan view of the absorbent body, an average of basis weights of the superabsorbent polymers of the any two adjacent concave portions is smaller than a basis weight of the superabsorbent polymer of the portion of the convex portion.

Description

Absorbent body, method for producing same, and absorbent article

Technical Field

The present invention relates to an absorbent body for an absorbent article, an absorbent article including the absorbent body, and a method for producing the absorbent body.

Background

Absorbent articles such as sanitary napkins and disposable diapers contain an absorbent body for absorbing liquid such as urine and menstrual blood, and the absorbent body is generally manufactured by: an absorbent core is formed by stacking hydrophilic fibers such as pulp and particles of Super Absorbent Polymer (SAP), and the absorbent core is covered with a core covering layer. In an absorbent body used in an absorbent article, in order to prevent a wearer from feeling uncomfortable due to the thickness of the absorbent body and deformation such as twisting during wearing, patent document 1 proposes embossing the absorbent body precursor with an embossing roll to reduce the thickness of the absorbent body and to provide rigidity. As a technique for imparting rigidity to an absorbent body by embossing, patent document 2 proposes: the cover (absorber precursor) is embossed using an embossing roll in which a plurality of projections provided on the outer peripheral surface of the roll each have a rectangular top surface, and the longitudinal direction of the top surface is parallel to the width direction (CD direction) of the embossing roll. Patent document 2 describes the following: when the protrusions hit the absorbent body precursor during rotation of the embossing roll, one of the top surfaces of the protrusions first hits the absorbent body precursor not in a point contact manner but in a line contact manner, so that the compression pressure of each protrusion can be dispersed in the width direction (CD direction) of the roll, and damage to the coating sheet (core layer) forming the outer periphery of the coating body can be prevented. If the wrapping sheet is broken, the SAP particles leak out from the broken portion, and thus the liquid absorption and retention performance of the absorbent body is lowered.

However, in recent years, it has been demanded for an absorbent body for an absorbent article to be thin without impairing absorption performance. However, in order to make the absorbent body thinner without impairing the absorption performance of the absorbent body, when the proportion of the SAP particles in the constituent components of the absorbent core constituting the absorbent body is increased, the SAP particles are bonded or aggregated at the portion compressed by embossing, and a portion (generally referred to as "hard spot") having a harder feel (feel) than the surrounding region tends to be generated. Hard spots can impart discomfort to the wearer of the absorbent article. Further, as described in patent document 3, as the speed of the manufacturing line of the absorbent core is increased and/or the thickness of the absorbent core is made thinner, the unevenness of the material constituting the absorbent core is more likely to increase, and therefore, hard spots are more likely to occur in a region where the basis weight or the ratio of the SAP particles is higher than that of the surroundings thereof in the manufacturing process of the absorbent core. In addition, when the absorbent body is made thinner, the more the embossing depth is increased by increasing the height of the convex portions on the outer peripheral surface of the embossing roll, the more easily the convex portions break the covering sheet (core wrap).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-33397

Patent document 2: japanese laid-open patent publication No. 2015-39385

Patent document 3: japanese patent laid-open No. 2012 and 510849

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide an absorbent body which can suppress the occurrence of hard spots, is less likely to be deformed, and exhibits good touch and wearing feeling, regardless of the presence or absence of a region containing a high content of a super absorbent polymer.

Means for solving the problems

As a result of studies to solve the above problems, the present inventors have found that, in the case described below, even if at least 1 region containing a high water-absorbent polymer at a high content is present, the generation of hard spots is suppressed, the resulting film has appropriate rigidity, is less likely to be deformed, and exhibits good feel to the skin and good wearing feeling: an absorbent for an absorbent article comprising an absorbent core comprising hydrophilic fibers and a particulate superabsorbent polymer and a core wrap covering the absorbent core and having a longitudinal direction, a width direction and a thickness direction, and a skin-side surface and a non-skin-side surface, the absorbent comprising a superabsorbent polymer content of 40 to 85 mass% and 0.15g/cm³At least 1 region having the above average density, the at least 1 region having a plurality of scattered concave portions and convex portions located between the plurality of concave portions on one surface or both surfaces of the skin-side surface and the non-skin-side surface, wherein the absorbent body is arbitrarily adjacent to each other in the longitudinal direction of the absorbent body in a plan view of the absorbent bodyThe average of the basis weights of the superabsorbent polymers in the two arbitrary adjacent concave portions is smaller than the basis weight of the superabsorbent polymer in the convex portion, in the two concave portions and the convex portion located between the two arbitrary adjacent concave portions.

The present inventors have also found that, when the laminate of the absorbent core and the core wrap is compressed by the embossing roll and the above-described plurality of scattered concave portions are formed on one side or both sides of the laminate having the 1 st surface and the 2 nd surface corresponding to the skin-surface-side surface and the non-skin-surface-side surface of the absorbent body, the damage to the core wrap can be significantly reduced in the following cases: each of the plurality of convex portions provided on the outer peripheral surface of the embossing roll includes a base portion and a dome portion having a hemispherical shape or an n-truncated pyramid shape (n is an integer of 4 or more), and in the compression step, an angle formed by a side surface of the dome portion on the downstream side in the transport direction of the laminate and the laminate when the dome portion of the convex portion comes into contact with the surface of the laminate as the embossing roll rotates is in a range of 0 to 60 degrees, and particularly preferably in a range of 0 to 30 degrees. Since the core wrap layer can be prevented from being damaged in the compression step, the rotational speed of the embossing roll can be increased, and the manufacturing speed of the absorbent body can be increased. In addition, when the absorbent body is made thin, the absorbent body is provided with rigidity without excessively increasing the density of the absorbent body, and therefore the embossing depth of the laminate can be increased. Even in the case where the absorbent core used in the compression process includes hard spots, it is possible to rearrange the SAP particles or crush the aggregated masses of the SAP particles by pressing deeply into the plurality of scattered protrusions of the embossing roll in the thickness direction of the absorbent core, and thus it is possible to eliminate or reduce the hard spots existing in the absorbent core before the compression process. Further, the SAP particles can be rearranged by deeply pressing the plurality of scattered convex portions of the embossing roll in the thickness direction of the absorbent core, and thus the generation of hard spots due to the compression process can be reduced. Therefore, the following absorber can be manufactured at high speed: the water-absorbent resin composition has a moderate stiffness, is less likely to be deformed, and gives a good skin feel and a good wearing feeling, while suppressing the generation of hard spots regardless of the presence of a region containing a high content of a super-absorbent polymer. The present invention has been completed based on the above findings.

That is, the present invention provides an absorbent body used in an absorbent article, comprising an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer and a core wrap covering the absorbent core, and having a longitudinal direction, a width direction, and a thickness direction, and a skin-side surface and a non-skin-side surface, the absorbent body being characterized in that,

the absorbent comprises a high water-absorbent polymer having a content of 40 to 85 mass% and 0.15g/cm³At least 1 region of the above average density, the at least 1 region having a plurality of recesses and protrusions between the plurality of recesses scattered on one or both of the skin-side surface and the non-skin-side surface, and

in a portion of any two adjacent concave portions and a convex portion located between the any two adjacent concave portions in the longitudinal direction of the absorbent body in a plan view of the absorbent body, an average of basis weights of the superabsorbent polymers of the any two adjacent concave portions is smaller than a basis weight of the superabsorbent polymers of the convex portion.

In another aspect, the present invention is an absorbent article including the absorbent body.

The present invention, in another aspect, is a method for producing the absorbent body described above, wherein,

the manufacturing method comprises the following steps:

(a) a core wrap covering the absorbent core to form a laminate having a1 st surface corresponding to the skin-side surface of the absorbent body and a2 nd surface corresponding to the non-skin-side surface of the absorbent body, and

(b) the absorbent body is formed by compressing one or both of the 1 st surface and the 2 nd surface of the laminate by an embossing roll rotating in the transport direction of the laminate while transporting the laminate,

the embossing roll has at least 1 region provided with a plurality of scattered convex parts on the outer peripheral surface,

the plurality of convex portions on the outer peripheral surface of the embossing roll each include a base portion and a top portion having a hemispherical shape or an n-truncated pyramid shape (n is an integer of 4 or more),

in the step (b), an angle formed by a side surface of the top portion on the downstream side in the transport direction and the laminate when the top portion comes into contact with the surface of the laminate as the embossing roll rotates is in a range of 0 to 60 degrees.

ADVANTAGEOUS EFFECTS OF INVENTION

The absorbent for absorbent articles of the present invention can suppress the occurrence of hard spots, is less likely to be deformed, and exhibits good skin feel and wearing feeling, regardless of whether the absorbent has a region containing a high content of a super absorbent polymer. The method for producing an absorbent body for an absorbent article of the present invention produces an absorbent body as follows: the core/sheath layer is less likely to be broken and hard spots are reduced regardless of the presence or absence of a region containing a high content of a super absorbent polymer, and the core/sheath layer is less likely to be deformed and exhibits a good feel to the skin and a good wearing feeling.

Drawings

Fig. 1 is a schematic plan view of an absorber according to an embodiment of the present invention.

Fig. 2 is an enlarged view of a region B of the absorbent body shown in fig. 1.

Fig. 3A is a schematic cross-sectional view along the line III-III of the region B of the absorbent body shown in fig. 1.

Fig. 3B is a schematic main part sectional view of an absorbent body of another embodiment of the present invention.

Fig. 4 is a schematic plan view of an absorbent body according to another embodiment of the present invention.

Fig. 5 is a schematic cross-sectional view of the absorbent body shown in fig. 4, taken along the line V-V.

Fig. 6 is a schematic plan view showing a state in which a disposable diaper including the absorbent body of the present invention is unfolded.

Fig. 7 is a perspective view schematically showing the disposable diaper shown in fig. 6 when deformed into a predetermined shape.

Fig. 8 is a schematic view showing an example of a manufacturing apparatus for manufacturing an absorbent body according to an embodiment of the present invention.

Fig. 9 is a schematic view showing an example of a manufacturing apparatus for manufacturing an absorbent body according to another embodiment of the present invention.

Fig. 10A is a three-dimensional view of an example of an embossing pin provided on the outer peripheral surface of an embossing roll.

Fig. 10B is a plan view showing an example of arrangement of the embossing pins (convex portions) when the outer peripheral surface of the embossing roll is viewed in plan.

Fig. 10C is a plan view showing another example of arrangement of the embossing pins (convex portions) when the outer peripheral surface of the embossing roll is viewed in plan.

Fig. 11A is a plan view showing an example of the shape of the top surface of the top of the embossing pin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan.

Fig. 11B is a plan view showing another example of the shape of the top surface of the top of the embossing pin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan.

Fig. 11C is a plan view showing another example of the shape of the top surface of the top of the embossing pin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan.

Fig. 11D is a plan view showing still another example of the shape of the top surface of the top of the embossing pin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan.

Fig. 12 is a three-dimensional view of another example of an embossing pin provided on the outer circumferential surface of an embossing roll.

Fig. 13 is a schematic enlarged view illustrating a nip between the embossing roll 805a and the anvil roll 805b of the compression device 805 in fig. 8.

FIG. 14 shows densities (g/cm) of the absorbers of examples 1 to 3³) Graph for stiffness (N).

FIG. 15 shows densities (g/cm) of absorbers of comparative examples 1 to 3³) Graph for stiffness (N).

FIG. 16 shows densities (g/cm) of absorbers of comparative examples 4 to 6³) Graph for stiffness (N).

Detailed Description

The following describes a part of embodiments of the invention related to the present invention.

[ solution 1]

An absorbent body for use in an absorbent article, comprising an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer and a core wrap covering the absorbent core, and having a longitudinal direction, a width direction, and a thickness direction, and a skin-side surface and a non-skin-side surface, the absorbent body being characterized in that,

the absorber contains a high water-absorbent polymer having a content of 40 to 85 mass% and 0.15g/cm³At least 1 region of the above average density, the at least 1 region having a plurality of recesses and protrusions between the plurality of recesses scattered on one or both of the skin-side surface and the non-skin-side surface, and

In the absorbent body of claim 1, in the above-described at least 1 region having the predetermined superabsorbent polymer content and average density, the average of the basis weights of the superabsorbent polymers of the arbitrary two adjacent concave portions is smaller than the basis weight of the superabsorbent polymers of the convex portions in the two arbitrary concave portions adjacent to each other in the longitudinal direction of the absorbent body in the portion of the convex portions located between the arbitrary two adjacent concave portions in a plan view of the absorbent body, and thus generation of hard spots is suppressed. In the absorbent body, a plurality of concave portions are formed on one or both of the skin-side surface and the non-skin-side surface in the at least 1 region having the predetermined high water-absorbent polymer content and average density, so that rigidity is imparted to the absorbent body, and since convex portions are present between the plurality of concave portions, the absorbent body is less likely to be deformed when an absorbent article including the absorbent body is worn by a wearer, and a soft and good skin touch and a good wearing feeling can be provided.

[ solution 2]

The absorbent body according to claim 1, wherein the average of the basis weights of the superabsorbent polymers in the two concave portions is 15% or more smaller than the basis weight of the superabsorbent polymer in the convex portion.

The absorbent body of claim 2 more reliably suppresses the generation of hard spots. Therefore, when the absorbent article including the absorbent body is worn by a wearer, the absorbent article is less likely to be deformed, and can more reliably provide a good skin feel and a good wearing feeling.

[ solution 3]

The absorbent body according to

claim

1 or 2, wherein the area ratio of the plurality of concave portions in the at least 1 region of the absorbent body in a plan view is 25% to 65% on one surface or both surfaces of the skin-surface-side surface and the non-skin-surface-side surface, respectively and independently.

When the area ratio of the concave portion is less than 25%, the effect of improving the rigidity is insufficient. If the area ratio of the concave portions is greater than 65%, the rigidity of the absorber may become too high.

[ solution 4]

The absorbent body according to any one of claims 1 to 3, wherein each of the plurality of concave portions has a thickness of 2mm in a plan view²～50mm²The absorbent core has a rectangular shape, and the interval between adjacent concave portions in the longitudinal direction of the absorbent core is 0.5mm to 10 mm.

The planar area of each concave part is less than 2mm²In the case of (2), since the contact area is small, the effect of suppressing the generation of hard spots by disposing the SAP again becomes small, and in addition, the risk of breakage of the core wrap increases. The planar area of each concave part is more than 50mm²In the case of (2), the rigidity of the absorber is increased, and there is a possibility that a good skin feeling is impaired. When the interval between adjacent concave portions in the longitudinal direction of the absorbent body is less than 0.5mm, the movement of SAP is restricted, and therefore the effect of suppressing the generation of hard spots is insufficient. In the longitudinal direction of the absorbent bodyWhen the interval between adjacent concave portions is larger than 10mm, there is a region where the SAP cannot be arranged again, and therefore the effect of suppressing the generation of hard spots is reduced.

[ solution 5]

The absorber according to any one of claims 1 to 4, wherein the absorber has a pair of deformation-inducing portions extending in a predetermined direction, and the plurality of concave portions are present between the pair of deformation-inducing portions.

An absorbent article comprising the absorbent according to claim 5 can prevent leakage of liquid such as urine and menstrual blood by fitting the absorbent article to a wearing area of a wearer.

[ solution 6]

An absorbent article comprising the absorbent according to any one of claims 1 to 5.

The absorbent article according to claim 6 is less likely to lose its shape when worn by a wearer, and provides a good skin feel and wearing feeling.

[ solution 7]

A method for producing an absorbent body for an absorbent article according to claim 1, wherein,

the method for producing the absorber includes the following steps:

(a) a laminate having a1 st surface corresponding to the skin surface side surface of the absorber and a2 nd surface corresponding to the non-skin surface side surface of the absorber, the laminate being formed by covering an absorbent core with a core wrap; and

the embossing roll has at least 1 region provided with a plurality of scattered protrusions on its outer circumferential surface,

the plurality of scattered convex parts on the outer peripheral surface of the embossing roll respectively comprise a base part and a top part in a hemispherical shape or an n-frustum pyramid shape (n is an integer of more than 4),

in the step (b), an angle formed by a side surface of the top portion on an upstream side in a rotation direction of the embossing roll and the laminate when the top portion comes into contact with the surface of the laminate as the embossing roll rotates is in a range of 0 to 60 degrees.

In the method of manufacturing an absorbent body according to claim 7, since the plurality of convex portions provided on the outer peripheral surface of the embossing roll used in the step (b) have hemispherical or n-truncated pyramid-shaped (n is an integer of 4 or more) top portions (distal end portions) and are not thin and sharp at acute angles, the core wrap layer is less likely to be damaged in the compression step. Further, since the plurality of convex portions of the embossing roll have a structure in which the top portions are joined to the outer peripheral surface of the embossing roll via the base portions, the laminate can be compressed deeper in the thickness direction thereof at a larger contact area ratio. After the top of the convex portion of the embossing roll comes into contact with the surface of the laminate, the laminate is compressed in the thickness direction while pushing the particles of the superabsorbent polymer apart at the top of the convex portion, and therefore, the laminate is compressed and compacted by the convex portion, and at the same time, a part of the superabsorbent polymer particles move around the concave portion. Therefore, according to the present invention, the basis weight of the super absorbent polymer is reduced in the portion (concave portion) compressed by the convex portion of the embossing roll as compared with that before the compression by the embossing roll, and the basis weight of the super absorbent polymer is increased in the portion (convex portion) adjacent to the compressed portion (concave portion) as compared with that before the compression by the embossing roll. That is, the occurrence of hard spots is suppressed by causing rearrangement of the super absorbent polymer particles by compression by the embossing roll. Further, assuming that hard spots derived from uneven distribution of the superabsorbent polymer particles exist in the absorbent core before compression by the embossing roll, the hard spots can be eliminated or reduced by the above-mentioned step (b).

[ definition of terms ]

The definitions are explained for terms used in this specification.

In the present specification, unless otherwise specified, the term "an object (for example, an absorbent article, an absorber, or the like) placed on a horizontal plane in a spread state as viewed from above in the vertical direction in the thickness direction of the object" will be simply referred to as "a top view".

The "width direction WD" refers to a direction (width direction) in which the length of the longitudinal object is short in a plan view, the "length direction LD" refers to a direction (length direction) in which the length of the longitudinal object is long in a plan view, and the "thickness direction TD" refers to a direction perpendicular to the object placed on a horizontal plane in a spread state (i.e., a thickness direction of the object), and the width direction WD, the length direction LD, and the thickness direction TD are orthogonal to each other.

The center axis C in the width direction extending in the longitudinal direction L is relatively close to the center axis W in the width direction of a vertically long object (for example, an absorbent article, an absorber, etc.)_LThe proximal end side of (a) is referred to as "inner side in the width direction", and is relatively distant from the width direction central axis line C in the width direction W of the vertically long object_LThe distal end side of (a) is referred to as "the lateral outer side". The longitudinal center axis C extending in the width direction W is relatively close to the longitudinal center axis L of the vertically long object in the longitudinal direction L_WThe proximal end side of (a) is referred to as "the inner side in the longitudinal direction", and is relatively distant from the longitudinal center axis C in the longitudinal direction L of the vertically long object_WThe distal end side of (a) is referred to as "the longitudinal outer side".

In the thickness direction TD of the absorbent article, "the proximal end side which is relatively close to the skin surface of the wearer when the absorbent article is worn" is referred to as "skin surface side", and "the distal end side which is relatively distant from the skin surface of the wearer when the absorbent article is worn" is referred to as "non-skin surface side".

In the absorbent body, "concave portion" refers to a portion of the absorbent body that is compacted in the thickness direction.

The "average value of basis weights of the super absorbent polymers" for two arbitrary adjacent concave portions in the longitudinal direction of the absorbent body means that the absorbent body has a super absorbent polymer content of 40 to 85 mass% and a 0.15g/cm³In the above region of average density, two recesses adjacent in the length direction for 10 pairs sampled randomlyAverage of the basis weights of the superabsorbent polymers.

The "basis weight of the super absorbent polymer" means an average of the basis weights of the portions of the projections located between 10 pairs of longitudinally adjacent two recesses sampled randomly as described above, with respect to the portions of the projections located between any adjacent two recesses in the longitudinal direction of the absorbent body.

In the absorbent body, "a portion of the convex portion located between any two adjacent concave portions in the longitudinal direction of the absorbent body" means a region surrounded by contour lines facing each other at the open ends of any two adjacent concave portions in the longitudinal direction of the absorbent body and two straight lines connecting the corresponding both end portions in the width direction of the contour lines to each other.

In the absorbent body, "a region having a plurality of scattered concave portions" means a region surrounded by the shortest envelope connecting the edge portions of the outermost concave portions of the plurality of scattered concave portions.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in order to facilitate understanding of the present invention, the drawings may not be drawn to the same scale and shape as the actual components. Like reference numerals designate like elements.

[ absorbent body ]

An absorbent body according to an embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a schematic plan view showing an embodiment of an absorbent body for a disposable diaper as an example. As shown in fig. 1, the absorbent body 100 has a longitudinal direction LD, a width direction WD, and a thickness direction TD (not shown) perpendicular to LD and WD, and includes an absorbent core 110 and a core wrap 120 covering the outer periphery of the absorbent core 110. FIG. 1 shows the skin-side surface of an absorbent body 100 worn by a wearer in a state of being incorporated in a disposable diaper, and shows an abdominal region A1 of the absorbent body 100 in contact with the abdominal-side skin surface of the wearer, a crotch abdominal region A2 of the absorbent body 100 in contact with the skin surface of the wearer on the crotch abdominal side, and an absorbent body in contact with the skin surface of the wearer on the crotch back sideA crotch back region A3 of the absorbent core 100, and a back region a4 of the absorbent core 100 that is in contact with the back skin surface of the back of the wearer. In the regions A1 to A4, there are regions A1c, A2c, A3c, and A4c in which a plurality of concave portions 140 are arranged at predetermined intervals in the longitudinal direction LD and the width direction WD. In the absorbent body 100, notch portions 112aR, 112aL, 112bR, 112bL, 112cR, and 112cL are also provided at the edges of the absorbent core 110. The plurality of concave portions 140 scattered in the regions A1c, A2c, A3c, and A4c are portions compacted by compression of the corresponding portions of the absorbent core and the core wrap in the thickness direction of the absorbent body 100, and are portions having a thickness smaller than the flat portion (hereinafter referred to as "outer edge portion") 130 of the outer edge of the region having the plurality of scattered concave portions 140. The absorbent body 100 is recessed in a concave shape with respect to the skin surface side surface of the outer edge 130 in the regions A1c to A4c, and the thickness of the absorbent body in the regions A1c to A4c is smaller than the thickness of the outer edge 130. The thickness of the region having the plurality of scattered concave portions and the thickness of the outer edge portion 130 were measured by a PEACOCK dial thickness gauge J-B (gauge head diameter: 50mm, pressure: 294Pa) manufactured by Kawasaki corporation. In fig. 1, an embodiment in which a plurality of concave portions 140 are arranged at predetermined intervals in the longitudinal direction LD and the width direction WD in the regions A1c, A2c, A3c, and A4c of the skin-side surface of the absorbent body 100 is shown, provided that the absorbent body of the present invention contains a superabsorbent polymer content of 40 to 85 mass% and 0.15g/cm³The absorbent body of the present invention is not limited to the embodiment illustrated in fig. 1, as long as the absorbent body has at least 1 region of the above average density, and each of the at least 1 region has a plurality of recesses and protrusions located between the plurality of recesses, which are scattered on one surface or both surfaces of the skin-side surface and the non-skin-side surface. Therefore, the plurality of concave portions shown in fig. 1 may be provided on the non-skin-side surface or both of the skin-side surface and the non-skin-side surface, instead of the skin-side surface of the absorbent body.

The absorbent core 110 contains at least hydrophilic fibers and particulate superabsorbent polymer. Examples of the hydrophilic fiber include cellulose-based water-absorbent fibers such as pulp. Further, hydrophilic synthetic fibers may be contained. Examples of the super absorbent polymer include super absorbent polymers generally used in absorbers for absorbent articles such as starches, celluloses, and synthetic polymers. In the densified portion of the absorbent body, the hydrophilic fiber density of the absorbent core is higher than that of the absorbent core in a portion where the densification is not performed.

The core wrap 120 is not particularly limited as long as it has a liquid-permeable property and a function of holding the constituent material of the absorbent core in the absorbent body, and examples thereof include tissue paper, nonwoven fabric, for example, through-air nonwoven fabric, spunbond/meltblown/spunbond (SMS) nonwoven fabric, and the like. In both cases where the core wrap is formed of tissue paper and where the core wrap is formed of nonwoven fabric, the basis weight is preferably 10g/m²～30g/m²。

When the superabsorbent polymer content in the above-mentioned at least 1 region provided with a plurality of scattered depressions is less than 40 mass%, it is difficult to achieve thinning of the absorbent body while maintaining the absorption performance of the absorbent body at a moderately high level, and when the superabsorbent polymer content is more than 85 mass%, discomfort may be given to the wearer in view of the crunchy feel of the SAP particles. In addition, when the content of the super absorbent polymer is more than 85 mass%, Gel blocking (Gel blocking) occurs, and the liquid absorption performance is lowered. The average density in the above-mentioned at least 1 region provided with a plurality of scattered concavities is less than 0.15g/cm³In the case of (2), it is difficult to achieve a moderate stiffness within the above-mentioned range of the content of the super absorbent polymer. The absorbent material of the present invention has a superabsorbent polymer content of 40 to 85 mass% and a concentration of 0.15g/cm³In at least 1 region of the above average density, the area ratio of the plurality of concave portions in a plan view is preferably 25% to 65%. When the area ratio of the concave portion is less than 25%, the effect of improving the rigidity is insufficient. If the area ratio of the concave portions is greater than 65%, the rigidity of the absorber may become too high. The superabsorbent polymer content can be determined for any region of the absorbent body in such a manner that: is cut from the absorbent coreAfter measuring the mass of each sample, the super absorbent polymer particles contained in each sample are sorted, the total mass of the super absorbent polymers contained in each sample is measured, and the ratio of the mass of the super absorbent polymer to the mass of each sample is calculated. The average density can be determined for any region of the absorbent body by using the average value obtained as follows: 5 samples (for example, 20mm × 50mm) of a predetermined length and width are cut out from the absorbent body, the mass of each sample is measured, and the average value is obtained by dividing the measured value by the volume of the sample obtained from the thickness and the area of the sample obtained by the aforementioned measurement method.

As will be described below with reference to fig. 2, when the skin-side surface of the absorbent body 100 having a plurality of scattered concave portions 140 is viewed in plan, the concave portions 140 have open ends 141 having a dimension of L1 in the width direction WD and a dimension of L2 in the longitudinal direction LD, and each concave portion has a bottom portion 142 having a dimension of L3 in the width direction WD and a dimension of L4 in the longitudinal direction LD of the absorbent body. L1 is preferably 2mm to 25mm, more preferably 2mm to 8mm, and still more preferably 3mm to 5 mm. L2 is preferably 1mm to 25mm, more preferably 1.5mm to 6mm, and still more preferably 2mm to 4 mm. The area S (L1 × L2) of the open end 141 of the recess is preferably 2mm²～50mm²More preferably 3mm²～30mm²More preferably 5mm²～20mm². The shortest interval L5 between the open ends of adjacent concave portions in the width direction WD of the absorbent body is preferably 0.5mm to 10mm, more preferably 1mm to 6mm, and still more preferably 2mm to 5 mm. The shortest interval L6 between the open ends of adjacent recesses in the longitudinal direction LD of the absorber is preferably 0.5mm to 10mm, more preferably 1mm to 6mm, and still more preferably 2mm to 5 mm. Here, L1 to L4 and S respectively mean that the absorbent material has a superabsorbent polymer content of 40 to 85 mass% and a superabsorbent polymer content of 0.15g/cm³In the region of the average density described above, the average values of L1 to L4 and S of 10 recesses sampled at random. L5 and L6 mean, respectively, that in the region of the absorbent body having the above-mentioned predetermined content and average density of superabsorbent polymer, the following appliesThe average value of the shortest intervals between the opening ends of the recessed portions adjacent to each other in the width direction WD and the length direction LD in 10 pairs of machine sampling. The "portion of the convex portion" located between two adjacent concave portions is an area surrounded by the

contour lines

141a and 141b facing each other at the open ends of two concave portions adjacent in the longitudinal direction of the absorber and two straight lines connecting the corresponding both end portions in the width direction of the contour lines to each other, and is denoted by reference numeral 146 in fig. 2. In fig. 2, the

contour lines

141a and 141b facing each other of the open ends of the adjacent two concave portions correspond to the sides facing each other of the open ends of the adjacent concave portions. The open end of the concave portion may be a circle such as a perfect circle, an oblong circle, or an ellipse, or a polygon such as a quadrangle, a pentagon, a hexagon, a heptagon, or an octagon when the absorbent body is viewed from above. As will be described below with reference to fig. 3A, the concave portions 140 are recessed by a depth d in the thickness direction TD of the absorbent body with reference to the surface regions between the convex portions between the plurality of concave portions, that is, between the open ends of the plurality of concave portions. The average value of the depth d, that is, the average depth is preferably 0.5mm to 5mm, more preferably 1.5mm to 3.5 mm. Here, "average depth" means a content of the super absorbent polymer in the absorbent body of 40 to 85 mass% and 0.15g/cm³Average of maximum depths of 10 recesses sampled randomly in the region of the above average density. The average values of L1 to L6 and S and the depth d of the recess can be measured by non-contact measurement using a laser displacement meter (for example, high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by yanshi corporation).

The notched portions 112aR to 112cR and 112aL to 112cL each have an orientation axis C_LThe tapered shape of the notch portion causes a difference in rigidity in the longitudinal direction of the absorbent core, and the absorbent body is easily folded along the folding lines BLa, BLb, and BLc in which the width of the absorbent core is locally narrow. As a result, when the absorber 110 is deformed and made into a solid, the bending range in which the end portions of the absorber do not interfere with each other can be widened, and therefore the absorber is easily deformed into a predetermined shape. As long as the end phase of the absorbent body can be preventedThe notch portion may take any shape such as a polygon or an arc by interference with each other. The absorbent core may not be provided with the notch portion. The core wrap layer constituting the absorber may be provided with a notch portion. The shape and size of the region where the plurality of concave portions 140 are scattered, the shape and size of the notch portion, the shape and size of the absorbent core, and the shape and size of the core cladding are not limited to the embodiment shown in fig. 1. In the case where the absorbent body has two or more regions having the above-described predetermined high water-absorbent polymer content and average density and provided with the plurality of concave portions as described above on one surface or both surfaces of the skin-side surface and the non-skin-side surface, the positions, shapes, and sizes of the plurality of concave portions 140 of the above-described regions, and the intervals between adjacent concave portions may be the same or different from each other in the two or more regions.

Fig. 2 is an enlarged view of a region B of the absorbent body 100 shown in fig. 1. In fig. 2, the concave portions 140 in a plan view of the skin surface side surface of the absorbent body 100 having the plurality of concave portions 140 scattered therein show the open end 141 having a dimension L1 in the width direction WD and a dimension L2 in the longitudinal direction LD, and show the bottom portion 142 having a dimension L3 in the width direction WD and a dimension L4 in the longitudinal direction LD of the absorbent body. The interval between the open ends of the adjacent concave portions in the widthwise direction WD of the absorbent body is denoted by L5, and the interval between the open ends of the adjacent concave portions in the longitudinal direction LD of the absorbent body is denoted by L6.

Fig. 3A is a schematic cross-sectional view of the region B of the absorbent body 100 shown in fig. 1, taken along the line III-III. In fig. 3A, the particles of the super absorbent polymer are denoted by reference numeral 114, the hydrophilic fibers are denoted by reference numeral 116, and the convex portions located between the plurality of concave portions 140 are denoted by reference numeral 145. The plurality of concave portions 140 are recessed by a depth d in the thickness direction TD of the absorbent body with reference to surface regions between the open ends of the plurality of concave portions, which are convex portions located between the plurality of concave portions. The bottom portion 142 includes a bottom surface 142a parallel to the in-plane direction of the absorber and an inclined surface 142b extending along the outer edge of the bottom surface 142a and inclined with respect to the in-plane direction of the absorber. The inclined surface 142b is inclined at preferably 10 to 60 degrees with respect to the in-plane direction of the absorbent body. In the absorbent body of the present invention, in the region having the predetermined content and average density of the superabsorbent polymer and provided with the plurality of scattered concave portions, the basis weight of the superabsorbent polymer in each concave portion is smaller than the basis weight of the superabsorbent polymer in a portion of the convex portion adjacent to each concave portion in the longitudinal direction of the absorbent body and a portion having the same plan view area as each concave portion. That is, as schematically shown in fig. 3A, the superabsorbent polymer particles 114 are present in the region 145a of the convex portion 145 adjacent to the concave portion 140, that is, the outer edge of the concave portion 140, at a basis weight higher than the basis weight of the superabsorbent polymer particles of the concave portion 140 in the longitudinal direction LD and the width direction WD of the absorbent body. Therefore, the absorbent body of the present invention suppresses the binding or aggregation of the superabsorbent polymer particles that cause the depressions of hard spots.

Fig. 3B is a schematic cross-sectional view showing another embodiment of the absorbent body of the present invention in which a plurality of concave portions scattered on both the skin-side surface and the non-skin-side surface are provided in at least 1 region of the above-described absorbent body 100 having a predetermined superabsorbent polymer content and average density. In fig. 3B, a plurality of concave portions having the same shape and size as the concave portions 140 provided on the non-skin-side surface, which is the opposite side of the convex portions 145 between the plurality of concave portions 140 provided on the skin-side surface at predetermined intervals, are denoted by reference numeral 140 ', and convex portions positioned between the plurality of concave portions 140 ' are denoted by reference numeral 145 '. The concave portions 140 ' are recessed by a depth d ' in the thickness direction TD of the absorbent body with the top surfaces of the convex portions 145 ' located between adjacent concave portions as reference surfaces. The bottom portion 142 'includes a bottom surface 142 a' substantially parallel to the in-plane direction of the absorbent body, and an inclined surface 142b 'extending along the outer edge of the bottom surface 142 a' and inclined with respect to the in-plane direction of the absorbent body. The inclined surface 142 b' is inclined at an angle of preferably 10 to 60 degrees with respect to the in-plane direction of the absorbent body. The region of the convex portion 145 'adjacent to the concave portion 140' and in which the super absorbent polymer particles 114 are present at a higher basis weight than that of the super absorbent polymer particles of the concave portion 140 'is denoted by reference numeral 145 a'. The size of the open ends 141 ' and the bottoms 142 ' in the width direction WD and the longitudinal direction LD of the absorbent body and the interval between the open ends of adjacent concave portions in the width direction WD and the longitudinal direction LD of the absorbent body can be independently selected within the above-described range for the skin-surface-side surface with respect to the plurality of concave portions 140 provided on the skin-surface-side surface with respect to the concave portions 140 ' provided on the skin-surface-side surface when the non-skin-surface-side surface having the plurality of concave portions 140 scattered therein of the absorbent body 100 is viewed in plan, and may be the same as or different from the plurality of concave portions 140 provided on the skin-surface-side surface. Further, at least 1 concave portion 140 of the plurality of concave portions 140 provided on the skin-surface-side surface and the plurality of concave portions provided on the non-skin-surface-side surface may at least partially overlap each other in the thickness direction TD of the absorbent body.

Fig. 4 is a plan view schematically showing an absorbent body according to another embodiment of the present invention. The absorbent body 100' shown in fig. 4 has, in addition to the axis C_LThe absorber of the embodiment shown in fig. 1 has the same configuration as the absorber of the embodiment shown in fig. 1 except for a pair of

deformation inducing portions

150R and 150L extending symmetrically in a predetermined direction (in the present embodiment, in the direction along the longitudinal direction L of the absorbent article). In the embodiment of the absorbent body shown in fig. 4, the

deformation inducing portions

150R and 150L are provided on the outer side in the width direction. The pair of deformation-inducing

portions

150R and 150L may be low basis weight regions having a lower basis weight than the peripheral regions of the deformation-inducing

portions

150R and 150L, respectively, whereby the absorbent body or the absorbent article incorporating the absorbent body can be easily bent with the deformation-inducing portions as the base axis. The shape of the pair of deformation-inducing

portions

150R and 150L can be set to a three-dimensional shape that makes it easier for the absorbent article incorporating the absorber to follow the wearing portion of the wearer. In order to improve the fit of the absorbent article including the absorbent body to the wearer, the absorbent body may include a pocket portion continuously or discontinuously formed in the deformation inducing portion. The basis weight of the deformation-inducing portion is not particularly limited, but is preferably 30 to 80 mass% of the basis weight of the outer edge portion 130.

Fig. 5 is a diagram for explaining an embodiment of the pair of

deformation inducing portions

150R and 150L, and is a schematic cross-sectional view along the V-V line of the absorbent body 100' shown in fig. 4. Fig. 5 shows an example in which the deformation-inducing

portions

150R and 150L are formed of low basis weight regions. In the embodiment shown in fig. 5, the low basis weight regions constituting the deformation-inducing

portions

150R and 150L have widths WR and WL in the width direction WD, respectively, and have a bottom Ba and inclined portions Sl on both sides thereof. In the low basis weight region, the basis weight of the bottom Ba is smallest, and in the slope section Sl, the basis weight sequentially increases as going away from the bottom Ba. The low basis weight region can be formed by the methods described in, for example, japanese patent application laid-open nos. 2010-233839 and 2016-123636 by the same applicant.

Fig. 6 is a schematic plan view showing a developed state of a disposable diaper including the absorbent body of the present invention, and fig. 7 is a perspective view schematically showing the disposable diaper shown in fig. 6 when deformed into a predetermined shape. As shown in fig. 6, the disposable diaper 1 has a shape elongated in the longitudinal direction LD in a plan view, and has a shape of a substantially hourglass in which a substantially central portion of the longitudinal direction LD is narrowed inward in the width direction WD. In the present invention, the outer shape of the absorbent article is not limited to such an outer shape, and any elongated shape (for example, a rectangle, an ellipse, a gourd-shape, or the like) can be adopted according to various applications as long as the length dimension in the longitudinal direction L is longer than the width dimension in the width direction W. The disposable diaper 1 of the present embodiment includes a liquid-permeable topsheet 2, a liquid-impermeable backsheet 3, and an absorbent body 4 of the present invention disposed between the topsheet 2 and the backsheet 3. The disposable diaper 1 further includes hydrophobic or water-

repellent side sheets

5 and 5 disposed on the skin surface side of the top sheet 2 to form a pair of leakage preventing walls, and

elastic members

6 and 6 extending in the longitudinal direction LD on the distal end side in the width direction WD of the side sheets. In the disposable diaper 1 shown in fig. 7, one end side of the longitudinal direction LD positioned below in fig. 6 is a ventral side covering the abdomen of the wearer, and the other end side of the longitudinal direction L positioned above is a back side covering the back (hip) of the wearer. The disposable diaper 1 of the present embodiment is a so-called tape-type disposable diaper which is worn by the wearer with the fastening tape 7 when worn. The disposable diaper according to one embodiment of the absorbent article of the present invention is not limited to a tape-type disposable diaper, and may be another type of disposable diaper such as a pants-type disposable diaper.

In the present embodiment, the topsheet 2 is a liquid-permeable sheet-like member that is disposed on the skin surface side of the absorbent body 4 and rapidly absorbs liquid excrement such as urine from the wearer or passes the liquid excrement through the sheet-like member to be transferred toward the absorbent body 4. In the present embodiment, the topsheet 2 is formed long in the direction along the longitudinal direction L of the disposable diaper 1. As the top sheet 2, any liquid-permeable sheet such as a nonwoven fabric, a woven fabric, a synthetic resin film having liquid-permeable holes formed therein, a mesh-like sheet having meshes, or the like can be used, but among them, a nonwoven fabric is preferably used in view of liquid permeability, flexibility, skin touch, or the like. The back sheet 3 is a liquid-impermeable sheet-like member disposed on the non-skin surface side of the disposable diaper 1 to prevent liquid excrement discharged from the wearer from leaking to the outside of the disposable diaper 1. The back sheet 3 is joined to the top sheet 2 and the

side sheets

5 and 5 with the absorbent member 4 interposed therebetween. For this joining, any joining means such as adhesion with a hot-melt adhesive or joining by various embossing treatments can be used. As the back sheet, any liquid-impermeable sheet such as a water-repellent nonwoven fabric, a synthetic resin film such as polyethylene or polypropylene, a composite sheet of a nonwoven fabric and a synthetic resin film, or a spunbond/meltblown/spunbond (SMS) composite nonwoven fabric can be used.

Fig. 8 is a schematic diagram for explaining an example of a manufacturing apparatus 800 used for manufacturing an absorbent body according to an embodiment of the present invention having a plurality of recesses scattered on one of a skin-side surface and a non-skin-side surface. In the present specification, a direction along the conveyance direction F of the material or product is also referred to as an MD direction, a direction orthogonal to the MD direction in a horizontal plane (i.e., a width direction of the manufacturing line) is referred to as a CD direction, and a direction orthogonal to the MD direction and the CD direction (i.e., an up-down direction of the manufacturing line) is referred to as a TD direction. The manufacturing apparatus 800 includes: a transport pipe 801 for transporting an absorbent material containing the opened hydrophilic fibers 8F and the particulate superabsorbent polymer 8S; a suction drum 802 which is rotatable and forms a1 st laminate 811 which is a precursor of an absorbent core of an absorbent body; a unwinding roller 804 for a core-clad continuous body for unwinding a long core-clad continuous body 812 covering the outer peripheral surface of the 1 st layered body 811; and a compression device 805. The compressing device 805 is used to form a plurality of concave portions 140 scattered on the skin surface side surface of the absorbent body, and includes a pair of rollers including an embossing roller 805a having a plurality of embossing pins (convex portions) protruding outward in the radial direction of the roller arranged on the outer peripheral surface thereof in accordance with the positions and shapes of the regions A1c to A4c of the absorbent body 100 shown in fig. 1, and an anvil roller 805b having a smooth outer peripheral surface. A plurality of concave mold members 803 arranged at a constant interval in the circumferential direction are provided on the outer circumferential surface of the suction drum 802, and the absorbent material is sucked into the concave mold members 803 and laminated. After the 1 st stacked body 811 formed by the mold member 803 is transferred from the suction drum onto the core-clad continuous body, the 2 nd stacked body 813 is formed by covering the 1 st stacked body 811 with the core-clad continuous body. The 2 nd stack 813 is transported to the compression device 805 and compressed by the compression device 805. The stack passing through the nip between the embossing roll 805a and the anvil roll 805b of the compression device 805 is denoted by reference numeral 814 in fig. 8. The particulate super absorbent polymer that can be used as the precursor for forming the absorbent core is not particularly limited as long as it is a super absorbent polymer that is generally used as an absorbent material for an absorbent article. The particulate superabsorbent polymer preferably has a particle size in the range of 150 to 850 μm and a number percentage of particles of 95% or more.

Therefore, when the absorbent body is produced by using the production apparatus 800, the 1 st step of forming the 1 st layered body 811 by layering the absorbent material containing the hydrophilic fibers 8F and the super absorbent polymer particles 8S, the 2 nd step of forming the 2 nd layered body 813 by covering the 1 st layered body 811 with the core-clad continuous body 812, and the 3 rd step of forming the 3 rd layered body 815 by compressing the 2 nd layered body 813 in the thickness direction by the compression apparatus 805 and performing embossing are sequentially performed. Further, a cutting device (not shown) for cutting the 3 rd stacked body 815 embossed by the compression device 805 into a desired shape to form a single absorbent body may be provided downstream of the compression device 805 in the transport direction F. Further, the manufacturing apparatus 800 is provided with devices such as a front sheet stacking device (not shown) for supplying and stacking the front sheet continuous body on the upper surface of the absorbent body, and a back sheet stacking device (not shown) for supplying and stacking the back sheet continuous body on the lower surface of the absorbent body, whereby an absorbent article such as a disposable diaper can be manufactured on line.

Fig. 9 is a schematic diagram for explaining an example of a manufacturing apparatus for manufacturing an absorbent body according to an embodiment of the present invention having a plurality of recesses scattered on both the skin-side surface and the non-skin-side surface.

The manufacturing apparatus 800' includes, similarly to the manufacturing apparatus shown in fig. 8: a transport pipe 801 for transporting an absorbent material containing the opened hydrophilic fibers 8F and the super absorbent polymer 8S; a suction drum 802 which is rotatable and forms a1 st laminate 811 which is a precursor of an absorbent core of an absorbent body; a unwinding roller 804 for a core-clad continuous body for unwinding a long core-clad continuous body 812 covering the outer peripheral surface of the 1 st layered body 811; and a compression device 805 (1 st compression device), and further includes a2 nd compression device 805 ' including a pair of rollers including an embossing roller 805a ' and an anvil roller 805b ' having a smooth outer peripheral surface. The embossing roll 805a 'and the anvil roll 805 b' of the 2 nd compressing device 805 'are located on the same side as the anvil roll 805 b' and the embossing roll 805a of the 1 st compressing device 805 with respect to the

stacked bodies

811, 813, 815 and 817, respectively. In the manufacturing apparatus 800 'of the embodiment shown in fig. 9, a plurality of concave portions are formed by the compression apparatus 805 (1 st compression apparatus) to be scattered on the skin surface side of the absorbent body, and a plurality of concave portions are formed by the compression apparatus 805' (2 nd compression apparatus) to be scattered on the non-skin surface side of the absorbent body. In fig. 9, a laminate passing through the nip between the embossing roll 805a ' and the anvil roll 805b ' of the compression device 805 ' is denoted by reference numeral 816, and a laminate having a skin-surface-side surface and a non-skin-surface-side surface subjected to embossing processing is denoted by reference numeral 817. In the production of the absorbent body using the production apparatus 800 ', a1 st step of forming a1 st layered body 811 by layering absorbent materials containing hydrophilic fibers 8F and super absorbent polymer particles 8S, a2 nd step of forming a2 nd layered body 813 by covering the 1 st layered body 811 with a core-clad continuous body 812, a3 rd step of forming a3 rd layered body 815 by performing embossing by compressing the 2 nd layered body 813 in the thickness direction by a1 st compression apparatus 805, and a4 th step of forming a4 th layered body 817 by performing embossing by compressing the 3 rd layered body 815 in the thickness direction by a2 nd compression apparatus 805' are sequentially performed.

Fig. 10A is a three-dimensional view of an example of an embossing pin (convex portion) provided on the outer peripheral surface of the embossing roll. The embossing pin 90 shown in fig. 10A includes a base 91 and a truncated quadrangular pyramid-shaped tip 92 which are bilaterally symmetrical with respect to a center axis in a direction perpendicular to the MD direction and the CD direction. The base portion 91 extends radially outward from a smooth reference surface (not shown) of the embossing roll, and the apex portion 92 extends radially outward from the top surface of the base portion. The top 92 of the embossing pin illustrated in fig. 10A has a quadrangular frustum shape, but the top 92 may have a hemispherical shape, a semi-ellipsoidal shape, a truncated conical shape, a polygonal frustum shape such as a pentagonal frustum, a hexagonal frustum, a heptagonal frustum, or an octagonal frustum. The base 91 of the embossing pin illustrated in fig. 10A has a quadrangular prism or a quadrangular frustum shape, but the base 91 may have a polygonal prism shape such as a cylindrical or truncated conical shape, a pentagonal prism, a hexagonal prism, a heptagonal prism, or an octagonal prism, or a polygonal frustum shape such as a pentagonal prism, a hexagonal prism, a heptagonal prism, or an octagonal frustum, depending on the bottom surface of the top. In the embossing pin illustrated in FIG. 10A, the top 92 has a top surface TS, an opposing side surface SS1 parallel to the CD direction, an opposing side surface SS2 parallel to the MD direction, a bottom surface BS1, and a height h₁The base has a top surface common to the bottom surface BS1 of the top, a bottom surface BS2 and a height h₂. The top surface TS, the bottom surface BS1 and the bottom surface BS2 are parallel to each other. The top surface TS of the top portion 92 has a length LT1 in the CD direction and a length LT2 in the MD direction, and the bottom surface BS1 of the top portion 92 and the top surface of the base portion have a length LB1 in the CD direction and a length LB2 in the MD direction. In fig. 10A, for simplicity, the base 91 is shown as a rectangular parallelepiped,but based on the tilt angle alpha in the MD and CD directions₁、β₁(i.e., the angle formed by the side surface SS1 of the top 92 and the bottom surface BS1 and the angle formed by the side surface SS2 of the top 92 and the bottom surface BS 1) is smaller than the inclination angle alpha₂、β₂(i.e., the angle formed by the side surface of the base portion parallel to the CD direction and the bottom surface of the base portion and the angle formed by the side surface of the base portion parallel to the MD direction and the bottom surface of the base portion), the base portion 91 may be in the shape of a cylinder or a truncated cone having a top surface common to the bottom surface of the top portion 92, or in the shape of an n-prism or an n-truncated pyramid (n is an integer of 4 or more). Angle of inclination alpha₁Preferably 10 to 60 degrees, and an inclination angle beta₁Preferably 10 to 60 degrees. At α₂And beta₂In the case of 90 degrees, the embossing pins 90 can be provided on the outer peripheral surface of the embossing roll at a higher density, so α₂And beta₂Preferably 90 degrees. Height h of the top₁And the height h of the base₂Total of (2) (═ h)₁+h₂) Is 1mm to 20mm, preferably 2mm to 4 mm. In the case where h is less than 1mm, the effect of compressing the laminate in the thickness direction is insufficient, and thus the effect of eliminating or reducing hard spots is insufficient. The embossing roll having a plurality of embossing pins with h greater than 20mm has a problem of the cost of manufacturing. Height h of the top₁Preferably 0.2mm to 2 mm. Height h of the base₂Preferably 1.8mm to 3.8 mm. The length LB1 in the CD direction of the bottom BS1 of the apex is preferably 2mm to 25mm, more preferably 2mm to 8mm, and still more preferably 3mm to 5 mm. The length LB2 in the MD of the bottom BS1 of the apex is preferably 1mm to 25mm, more preferably 1.5mm to 6mm, and still more preferably 2mm to 4 mm. The length LT1 in the CD direction of the top surface TS of the top is preferably 1mm to 20mm, more preferably 2mm to 5mm, and still more preferably 2.5mm to 5 mm. The top surface TS of the top portion has a length LT2 in the MD direction of preferably 0.5mm to 15mm, more preferably 1mm to 5mm, and still more preferably 1mm to 3 mm. The area of the bottom surface BS2 of the base is preferably 2mm²～50mm²More preferably 3mm²～30mm²More preferably 5mm²～20mm². Spacing between adjacent embossing pins in the CD and MD directions, i.e. of the sides of the bases of adjacent embossing pinsThe shortest distances D1 and D2 are preferably 0.5mm to 13mm, more preferably 1mm to 6mm, and still more preferably 1mm to 5 mm. LT1, LT2, LB1, LB2, h can be determined according to the shape, size and interval of the recesses to be formed in the absorbent body, the radius of the embossing roll, and the like₁、h₂、α₁、β₁、α₂、β₂The values of D1 and D2, and the size and shape of BS 2.

Fig. 10B and 10C are plan views illustrating an arrangement of the embossing pins (convex portions) when the outer circumferential surface of the embossing roll is viewed from above. In addition, the base of the knurling pin is omitted in fig. 10B and 10C for the sake of simplicity. Fig. 10B shows an embodiment in which a plurality of embossing pins have a quadrangular frustum pyramid shaped top and are arranged side by side at predetermined intervals D1 and D2 in the CD direction and the MD direction, respectively. Fig. 10C shows an embodiment in which a plurality of embossing pins have octagonal frustum-shaped tops and are arranged in a staggered manner, that is, alternately. In fig. 10C, the interval between the tops adjacent in the CD direction is denoted by D1, and the interval between the tops adjacent in the MD direction is denoted by D2. The interval between adjacent embossed pins is determined in accordance with the interval between adjacent concave portions of the absorbent body. The plurality of embossing pins may be arranged in an arrangement other than the arrangement shown in fig. 10B and 10C as long as the effect of the present invention is not impaired. For example, the embossing pins may be arranged in regular or irregular arrays so that the area ratio of the embossing pins in a plan view of the outer circumferential surface of the embossing pins is 25% to 65%. In order to provide the absorbent body with an appearance and prevent generation of a portion having locally high rigidity, the embossing pins are preferably regularly arranged at constant intervals.

Fig. 11A to 11D are plan views illustrating the shape of the top surface of the top of the embossing pin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan. The top surface of the top portion may have a rectangular shape with four corners at right angles as shown in fig. 11A, a shape with corners chamfered in an R-shape as shown in fig. 11B, and a shape with corners chamfered in a C-shape as shown in fig. 11C. The top surface of the top portion may also be oblong as shown in fig. 11D. The top may be hemispherical or semi-spheroid in shape. When the top surface of the top portion of the embossing pin has a shape with an R-shaped chamfered corner and a C-shaped chamfered corner as shown in fig. 11B to 11D, as will be described below with reference to fig. 12, when the top portion of the embossing pin hits the laminated body at the time of embossing the laminated body, the compression pressure applied to the laminated body can be dispersed, and the core clad layer can be prevented from being damaged.

Fig. 12 schematically shows yet another example of an embossing pin. The embossing pin of the embodiment shown in fig. 12 includes a base 1110 and a top 1120, the base 1110 has an octagonal prism shape, and the top 1120 has a top surface TS having a shape corresponding to a rectangle with four corners rounded off in an R-shape, a side surface SS rounded off in an R-shape, a bottom surface BS1 having a shape corresponding to a rectangle with a C-shape (i.e., an octagon), and a height h₁The base has a top surface common to the bottom surface BS1 of the top, a bottom surface BS2 and a height h₂. The top surface TS of the top portion has a length LT1 in the CD direction, LT2 in the MD direction, and the bottom surface BS1 of the top portion has a length LB1 in the CD direction and LB2 in the MD direction. In fig. 11, the base 91 is shown as an octagonal prism for simplicity, but is based on an angle α formed by the side surface of the top 92 and the bottom surface BS1 in the MD direction and the CD direction₁、β₁Less than the angle alpha formed by the side surface and the bottom surface of the base part₂、β₂Under such a condition, the base 91 may be an n-prism or n-truncated pyramid shape (n is an integer of 4 or more) having a top surface common to the bottom surfaces of the crests 92. The embossing roll having a plurality of embossing pins with h greater than 20mm has a problem of the cost of manufacturing. When the compression step is performed using an embossing roll having a plurality of embossing pins illustrated in fig. 11 on the outer peripheral surface, the effect of preventing the core-clad layer from being damaged when the top of the embossing pin comes into contact with the laminate can be further improved.

Fig. 13 is a schematic enlarged view of the nip between the embossing roll 805a and the anvil roll 805b of the compression device 805 in fig. 8. Fig. 13 shows a process in which, when the laminate 814 conveyed in the conveying direction F passes through the nip between the embossing roll 805a and the anvil roll 805b, one surface of the laminate 814 is compressed by the embossing pin (convex portion) 90 having the base portion 91 and the top portion 92 to form the concave portion. In the method for producing an absorbent body of the present invention, when the crests 92 of the embossing pins 90 provided on the outer peripheral surface of the embossing roll 805a rotating in the same direction as the transport direction F of the laminate 814 come into contact with the surface of the laminate 814 as the embossing roll 805a and the anvil roll 805b rotate, the angle θ formed between the side SS of the crests 92 on the downstream side in the transport direction of the laminate and the surface of the laminate 814 is in the range of 0 to 60 degrees. The angle θ is preferably 0 to 30 degrees. The larger the angle θ, the more difficult it is to disperse the compression pressure applied to the laminate when the tip of the embossing pin comes into contact with the laminate, and therefore the effect of preventing the core clad from being damaged becomes lower.

The absorbent article of the present disclosure is not particularly limited, and examples thereof include absorbent articles that mainly absorb urine, such as disposable diapers, urine-absorbing pads, and animal-use urine-discharging sheets, absorbent articles that mainly absorb menstrual blood, such as sanitary napkins and panty liners.

[ examples ] A method for producing a compound

The present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited to the examples.

(1) Production of absorbent body

[ examples 1 to 10]

Using the manufacturing apparatus shown in FIG. 8, a1 st laminate (corresponding to a precursor of an absorbent core) having a length of 115 mm. times.330 mm in width was formed from an absorbent material containing pulp (NB 416 manufactured by Weyerhauser) and SAP particles (SA 60S manufactured by Sumitomo Seisaku Co., Ltd.) having a basis weight shown in Table 1 below, and an SMS nonwoven fabric (having a basis weight of 10 g/m) was used as a core wrap layer²) The 1 st laminate was coated to form a2 nd laminate, and then the 2 nd laminate was compressed at a nip interval of 0.5mm to 0.7mm and a nip pressure of 0.15MPa by a compression device including a pair of rolls, i.e., an embossing roll and an anvil roll, in which a plurality of embossing pins were arranged on the outer peripheral surface, and cut into a size of 130mm in length × 360mm in width to produce an absorbent body. The speed of the 2 nd laminate through the nip was about 5 m/s. As shown in fig. 12, the base of the embossing pin of the embossing roll used in examples 1 to 10 was octagonal. The embossing pins of the embossing rolls used in examples 1 to 10 had a shape in which the four corners of the top surface were chamfered at R0.25 and the four corners of the bottom surface were chamfered at C0.9. In the embossing rolls used in examples 1 to 3, as shown in fig. 10C, the embossing pins were arranged in a staggered pattern. Examples 4 to 10In the embossing roll, as shown in fig. 10B, the embossing pins are arranged in a side-by-side pattern in the MD direction and the CD direction. Table 1 below shows the dimensions of the top portions of the embossing pins of the embossing roll used in examples 1 to 10 (i.e., the CD-direction length LT1 of the top surface, the MD-direction length LT2 of the top surface, the CD-direction length LB1 of the bottom surface, and the MD-direction length LB2 of the bottom surface), and the shortest intervals D1, D2 between adjacent embossing pins in the CD direction and the MD direction. In addition, the side surface of the top part forms an angle alpha with the bottom surface in the CD direction and the MD direction₁、β₁Both of which are 30 degrees, the side surface of the base and the bottom surface form an angle alpha₂、β₂Both at 90 degrees. Thus, the area of the bottom surface of the base of the embossing pin is equal to the area of the bottom surface of the top. At an angle alpha₂、β₂In the case where both are 90 degrees, when the lengths in the CD direction and the MD direction of the bottom surface of the top portion are represented as LB1 and LB2, respectively, and the shortest intervals between the embossing pins in the CD direction and the MD direction are represented as D1 and D2, respectively, the following formula (1) can be satisfied in the staggered arrangement:

S_r＝(LB1×LB2)/{2×(LB1+D1)×(LB2+D2)}

determining the area ratio S of the bottom surface of the base of the ginning pin_r，

In the parallel arrangement, the following formula (2) can be used:

S_r＝(LB1×LB2)/{(LB1+D1)×(LB2+D2)}

determining the area ratio S of the bottom surface of the base of the ginning pin_r。

[ TABLE 1]

TABLE 1

[ comparative examples 1 to 3]

Absorbers of comparative examples 1 to 3 were produced in the same manner as the absorbers of examples 1 to 3, respectively, except that a flat press was used instead of the embossing roll. The flat press was set to a gap of 0mm, a press pressure of 5.8MPa and a press time of 5 seconds.

[ comparative examples 4 to 6]

The absorbent bodies of comparative examples 4 to 6 were produced in the same manner as in examples 1 to 3, except that embossing rolls were used in which a plurality of square-truncated-pyramid-shaped embossing pins having a top surface of 1.40mm × 0.60mm in dimension, a bottom surface of 2.30mm × 1.50mm in dimension, a height of 0.45mm, and 4 side surfaces forming 45-degree angles with the bottom surface were provided on the outer peripheral surface at intervals of 2.70mm in the CD direction and at intervals of 4.5mm in the MD direction. The shape and size of the embossing pin correspond to the projections formed on the outer peripheral surface of the upper roller of the embossing processing device described in patent document 2.

(2) Method for evaluating absorber

The absorbers of examples 1 to 10 and comparative examples 1 to 6 were evaluated by the following evaluation methods.

[ X-ray CT Observation ]

The distribution of the superabsorbent polymer in the absorber was investigated by observing the internal structure of the absorber in a non-destructive manner using an X-ray CT apparatus. The X-ray CT apparatus used was FLEX-M863 manufactured by Beamsense (Ltd.). The software used for X-ray CT imaging was BSFM manufactured by Beamsense, the software used for image synthesis was Beamsense CT, and the software used for image analysis was Volume Extractor. The tube voltage 40kV, the tube current 100. mu.A, and the photographing time per 1 time were 1 second. An absorber sample is placed and fixed on a stage which can be rotated by 360 degrees around a rotation axis perpendicular to an axis line connecting centers of an X-ray source and a two-dimensional detector, and the absorber sample is imaged 1 time at 0.5 degrees while being rotated by 360 degrees, thereby obtaining 720 images in total. The 720 images were combined. Two embossed depressions that are adjacent to each other in the longitudinal direction of the absorber sample in 10 pairs in a plan view of the absorber sample are randomly sampled from the X-ray CT synthetic image, and the average basis weight of the superabsorbent polymer in the embossed depressions is determined (b 1). Then, the average value of the basis weight of the super absorbent polymer in the convex portion between the 10 pairs of adjacent embossed concave portions sampled randomly was obtained (b 2). The percentage of b1 relative to b2, i.e., the value of 100 × b1/b2, was determined. Table 2 shows the values of 100 Xb 1/b2 in examples 1 to 10. In comparative examples 1 to 6, no bias was observed in the distribution of the super absorbent polymer under the X-ray CT observation conditions.

[ TABLE 2]

TABLE 2

[ rigidity test ]

A sample of 20mm by 50mm in size was drawn out from the absorber, and the mass and thickness of the sample were measured. The mass was measured by an electronic scale, and the thickness was measured by a PEACOCK dial thickness gauge J-B (diameter of a gauge head: 50mm, pressure: 294Pa) manufactured by Kawasaki corporation. A digital dynamometer (FGP-2 manufactured by NIDEC-shipo corporation, japan) was attached to a dynamometer frame (FGS-50S manufactured by NIDEC-shipo corporation), an attachment portion (indenter) of a 3-point bending jig (GA-10N manufactured by joy motor, japan) was attached to a stylus attachment portion of the digital dynamometer, and a base portion of the 3-point bending jig was disposed on a measurement table of the dynamometer frame. The radius of the pressure head is 2.5mm, and the radius of the fulcrum is 2.5 mm. The sample was placed on the base of the bending jig so that the tip of the pressing portion (indenter) of the bending jig was in contact with the center of the sample, with the opening width set to 15 mm. The sample was loaded at a crosshead speed of 1.5mm/s and the maximum load at which the sample bent was recorded as the stiffness value. The evaluation results of the stiffness are shown in tables 3 to 5 together with the density of the absorber determined from the above-mentioned size, mass and thickness of the absorber.

[ TABLE 3]

TABLE 3

[ TABLE 4]

TABLE 4

[ TABLE 5]

TABLE 5

[ TABLE 6]

TABLE 6

[ TABLE 7]

TABLE 7

FIG. 14 shows densities (g/cm) of the absorbers of examples 1 to 3, which were embossed using an embossing roll according to the present invention³) Graph for stiffness (N). FIG. 15 shows densities (g/cm) of comparative examples 1 to 3 in which embossing was performed using a flat press³) Graph for stiffness (N). FIG. 16 shows densities (g/cm) of absorbers of comparative examples 4 to 6, which were embossed using embossing rolls³) Graph for stiffness (N).

[ TABLE 8 ]

TABLE 8

As is clear from FIGS. 14 to 16 and Table 8, in examples 1 to 3, the regions having a relatively low absorber density (i.e., absorber density of 0.2 g/cm) were found to be present in comparison with comparative examples 1 to 3 and comparative examples 4 to 6³Above and less than 0.3g/cm³Region (s)) having a relatively high stiffness and a relatively high absorbent density (i.e., absorbent density of 0.4g/cm³Above and less than 0.5g/cm³Area) is smaller (i.e., the deviation is smaller). The samples of comparative examples 1 to 3 and comparative examples 4 to 6 had extremely high rigidity, i.e., so-called hard spots.

[ evaluation of touch feeling ]

The samples of examples 1 to 3 and comparative examples 1 to 6 were subjected to sensory evaluation for the tactile sensation by 10 skilled participants, and the evaluation results were ranked on a scale of 1 to 3.

Grade 1: hard spots are not touched, and the diaper is suitable for being used in baby diapers.

Grade 2: it is slightly hard to touch but is acceptable for use in diapers for babies.

Grade 3: contains a very hard portion and is not suitable for use in a baby diaper.

The total of the evaluation points is determined by assigning an evaluation point of "0 point" to the sample evaluated as level 1, assigning an evaluation point of "1 point" to the sample evaluated as level 2, and assigning an evaluation point of "2 point" to the sample evaluated as level 3. The smaller the total of evaluation points, the better the feeling, and the more suitable it is for use in a diaper for infants.

[ TABLE 9 ]

TABLE 9

As is clear from Table 9, examples 1 to 3 of the present invention have a more suitable feel for use in diapers for infants than comparative examples 1 to 3.

Description of the reference numerals

1. A disposable diaper; 2. a liquid-permeable surface sheet; 3. a liquid-impermeable back sheet; 5. 5, side pieces; 6. 6, an elastic member; 7. a hook and loop fastener; 4. 100, 100', absorber; 110. an absorbent core; 114. 8S, superabsorbent polymer particles; 116. 8F, hydrophilic fibers; 120. a core cladding; 130. an outer edge portion; 140. 140', a recess; 141. 141', open ends of the recesses; 142. a bottom of the recess; 142a, 142 a', the bottom surface of the bottom; 142b, 142 b', inclined faces of the bottom; 145. 145', a convex part; 145a, a region adjacent to the recess; 146. a portion of the boss; 150R, 150L, deformation inducing part; 800. 800', an absorbent body manufacturing apparatus; 801. a delivery pipe; 802. a suction drum; 803. a concave mold member; 804. unwinding rollers; 805. 805'A compression device; 805a, 805 a', embossing rolls; 805b, 805 b', an anvil roll; 811. a1 st stacked body; 812. a core-cladding continuum; 813. a2 nd laminated body; 814. 816, a laminate; 815. a3 rd laminated body; 817. a4 th stacked body; 90. rolling a flower pin; 91. a base; 92. a top portion; D. d', recess depth; H. ginning pin height; alpha is alpha₁、β₁、α₂、β₂And an inclination angle.

Claims

1. An absorbent body for use in an absorbent article, comprising an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer and a core wrap covering the absorbent core, and having a longitudinal direction, a width direction, and a thickness direction, and a skin-side surface and a non-skin-side surface, the absorbent body being characterized in that,

2. The absorbent body according to claim 1, wherein,

the plurality of scattered concave portions are portions of the absorbent body which are compacted in the thickness direction.

3. The absorbent body according to claim 1, wherein,

the average of the basis weights of the superabsorbent polymers in the two concave portions is 15% or more smaller than the basis weight of the superabsorbent polymer in the convex portion.

4. The absorbent body according to claim 1 or 2, wherein,

the area ratio of the plurality of concave portions in the at least 1 region of the absorbent body in a plan view is 25% to 65% on one surface or both surfaces of the skin-side surface and the non-skin-side surface, respectively.

5. The absorbent body according to claim 1 or 2, wherein,

the concave portions are respectively 2mm in a plan view²～50mm²The absorbent core has a rectangular shape, and the interval between adjacent concave portions in the longitudinal direction of the absorbent core is 0.5mm to 10 mm.

6. The absorbent body according to claim 1 or 2, wherein,

the absorber has a pair of deformation-inducing portions extending in a predetermined direction, and the plurality of concave portions are present between the pair of deformation-inducing portions.

7. An absorbent article in which, in the case of a disposable absorbent article,

an absorbent article comprising the absorbent according to any one of claims 1 to 6.

8. A method for producing an absorbent body for an absorbent article according to claim 1, wherein,

the method for producing the absorber includes the following steps:

(a) a laminate having a1 st surface corresponding to the skin-surface-side surface of the absorber and a2 nd surface corresponding to the non-skin-surface-side surface of the absorber, the laminate being formed by covering an absorbent core with a core wrap; and

(b) the absorbent body according to claim 1, wherein the absorbent body is formed by compressing one or both of the 1 st surface and the 2 nd surface of the laminate by an embossing roll rotating in the transport direction of the laminate while transporting the laminate,

the embossing roll has at least 1 region provided with a plurality of scattered convex parts on the outer circumferential surface thereof,

the plurality of scattered convex portions on the outer peripheral surface of the embossing roll each include a base portion and a hemispherical or n-truncated pyramid shaped top portion,

in the step (b), an angle formed by a side surface of the top portion on the downstream side in the transport direction and the laminate when the top portion comes into contact with the surface of the laminate with the rotation of the embossing roll is in a range of 0 to 60 degrees,

wherein n is an integer of 4 or more.