JP6755334B2 - Absorbent, its manufacturing method, and absorbent article - Google Patents

Description

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

Absorbent articles such as sanitary napkins and disposable diapers include absorbers for absorbing liquids such as urine and menstrual blood, which are generally hydrophilic fibers such as pulp and superabsorbent polymers. It is produced by forming an absorption core by depositing particles of (Superabsorbent Polymer: SAP) and coating the absorption core with a core wrap. For the absorber used in the absorbent article, the absorber precursor is embossed with an embossing roll in order to prevent discomfort during wearing due to the thickness of the absorber and deformation such as twisting during wearing. As a result, it is proposed in Patent Document 1 that the thickness of the absorber is reduced to impart rigidity. Regarding the technique of imparting rigidity to the absorber by embossing, a plurality of convex portions provided on the outer peripheral surface of the roll each have a rectangular top surface, and the longitudinal direction of the top surface is the width direction of the embossed roll. Patent Document 2 proposes embossing a coating (absorbent precursor) using an embossing roll parallel to (CD direction). In Patent Document 2, when each convex portion hits the absorber precursor during embossing roll rotation, one side of the top surface of each convex portion first hits the absorber precursor by line contact instead of point contact. It is described that the pressing pressure due to each convex portion can be dispersed in the width direction (CD direction) of the roll, and the coating sheet (core wrap) forming the outer peripheral portion of the covering body can be prevented from being damaged. When the coating sheet is damaged, SAP particles leak from the damaged portion, so that the liquid absorption and holding performance of the absorber deteriorates.

By the way, in recent years, it has been required to reduce the thickness of an absorber for an absorbent article without impairing its absorbability. However, when the proportion of SAP particles in the constituents of the absorption core constituting the absorber is increased in order to reduce the thickness without impairing the absorbency of the absorber, the SAP particles in the portion squeezed by the embossing process. Are likely to coalesce or aggregate to form a portion of the texture (feeling to the touch) that is harder than the surrounding area (generally called a "hard spot"). Hard spots can make the wearer of the absorbent article feel uncomfortable. Further, as described in Patent Document 3, as the speed of the absorption core production line is increased and / or the thickness of the absorption core is reduced, the non-uniformity of the material constituting the absorption core increases. Because of this, hard spots are likely to occur in regions where the basis weight or proportion of SAP particles is higher than their surroundings during the manufacture of the absorption core. Further, when the thickness of the absorber is reduced, the height of the convex portion on the outer peripheral surface of the emboss roll is increased to increase the embossing depth, so that the convex portion easily breaks through the covering sheet (core wrap).

Japanese Unexamined Patent Publication No. 2003-33397 JP-A-2015-39385 Japanese Unexamined Patent Publication No. 2012-510894

The present invention has been made in view of the above problems, and although it has a region containing a super absorbent polymer at a high content rate, the generation of hard spots is suppressed, and the shape is not easily lost, which is good. It is an object of the present invention to provide an absorber that gives a feeling of touch and wearing.

As a result of studies to solve the above problems, the present inventors include an absorption core containing a hydrophilic fiber and a superabsorbent polymer in the form of particles, and a core wrap covering the absorption core in the length direction. In an absorber for an absorbent article having a skin surface side surface and a non-skin surface side surface in the width direction and the thickness direction, the absorber has a superabsorbent polymer content of 40 to 85% by mass and 0. At least one region having an average density of 15 g / cm ³ or more, which is located between a plurality of recesses scattered on one or both of the skin surface side surface and the non-skin surface side surface, and the plurality of recesses. It has at least one region having a convex portion, and when the absorber is viewed in a plan view, it is between any two adjacent recesses in the length direction of the absorber and the two adjacent recesses. High water absorption when the average value of the superabsorbent polymer basis weight in the two adjacent concave portions is smaller than the basis weight of the superabsorbent polymer in the convex portion. It has been found that the generation of hard spots is suppressed despite having at least one region containing a high polymer content, it has appropriate rigidity, it does not easily lose its shape, and it provides a good feel and wearing feeling. It was.

Furthermore, the present inventors squeeze the laminate of the absorbent core and the core wrap with an embossed roll to have first and second surfaces corresponding to the skin surface side surface and the non-skin surface side surface of the absorber, respectively. When forming the plurality of scattered recesses on one or both of the laminated bodies, the plurality of convex portions provided on the outer peripheral surface of the embossed roll are hemispherical or n-square cone trapezoidal shape (n is 4) with the base, respectively. The side surface of the top of the convex portion on the downstream side in the transport direction of the laminated body and the laminated body when the top of the convex portion comes into contact with the surface of the laminated body according to the rotation of the embossing roll in the pressing process including the top of the above integer) It has been found that damage to the core wrap can be significantly reduced when the angle formed by the above is in the range of 0 to 60 degrees, particularly preferably 0 to 30 degrees. Since the breakage of the core wrap in the squeezing step can be suppressed, the rotation speed of the embossed roll can be increased, thereby increasing the production speed of the absorber. Further, when the absorber is thinned, the embossing depth of the laminated body can be increased in order to impart rigidity to the absorber without increasing the density of the absorber too much. Even if the absorption core subjected to the squeezing process contains hard spots, the SAP particles can be rearranged or the agglomerates of the SAP particles can be decompressed by deeply pushing the multiple interspersed protrusions of the embossed roll in the thickness direction of the absorption core. Since it can be crushed, the hard spots that were present in the absorption core prior to the squeezing process can be eliminated or reduced. Further, since the SAP particles can be rearranged by deeply pushing the plurality of scattered protrusions of the embossed roll in the thickness direction of the absorption core, the generation of hard spots due to the pressing step can be reduced. Therefore, although it has a region containing a super absorbent polymer at a high content rate, the generation of hard spots is suppressed, it has appropriate rigidity, it does not easily lose its shape, and it has a good feel and wearability. It is possible to manufacture the body at high speed. The present invention has been completed based on the above findings.

That is, the present invention, in one embodiment,
It contains an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer, and a core wrap covering the absorbent core, and includes a length direction, a width direction, a thickness direction, and a skin surface side surface and a non-skin surface. An absorber for absorbent articles with a side surface,
The absorber is at least one region having a super absorbent polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more, and is a skin-side surface and a non-skin-side surface. One or both have at least one region having a plurality of interspersed recesses and protrusions located between the plurality of recesses, and the length of the absorber when the absorber is viewed in a plan view. For the portion of the convex portion located between any two adjacent recesses in the longitudinal direction and the two adjacent recesses, the average value of the basis weight of the superabsorbent polymer in the two adjacent recesses is Less than the basis weight of the superabsorbent polymer in the convex portion,
It is an absorber characterized by.

The present invention, in another embodiment, is an absorbent article comprising the absorber.

The present invention is, in a further embodiment, a method for producing the above-mentioned absorber.
(A) A step of covering the absorption core with a core wrap to form a laminate having first and second surfaces corresponding to the skin surface side surface and the non-skin surface side surface of the absorber, respectively, and (b). A step of squeezing one or both of the first surface and the second surface of the laminate with an embossing roll rotating in the transport direction of the laminate to form the absorber while conveying the laminate.
The embossed roll has at least one region provided with a plurality of scattered protrusions on the outer peripheral surface thereof.
Each of the plurality of convex portions on the outer peripheral surface of the embossed roll includes a base portion and a top portion having a hemispherical or n-side pyramidal trapezoidal shape (n is an integer of 4 or more).
In the step (b), the angle formed by the side surface of the top and the laminate on the downstream side in the transport direction when the top comes into contact with the surface of the laminate according to the rotation of the emboss roll is 0 to 60 degrees. Is within the range of
This is a method for manufacturing an absorber.

Although the absorber for an absorbent article of the present invention has a region containing a super absorbent polymer at a high content rate, the generation of hard spots is suppressed, the shape is not easily lost, and the texture is good. Shows a feeling of wearing and a feeling of wearing. The method for producing an absorber for an absorbent article of the present invention reduces core wrap breakage and occurrence of hard spots despite having a region containing a high content of super absorbent polymer, and is less likely to lose its shape. Provides an absorber that exhibits a good feel and feel.

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 the area B of the absorber shown in FIG. FIG. 3A is a schematic cross-sectional view taken along line III-III of region B of the absorber shown in FIG. FIG. 3B is a schematic cross-sectional view of a main part of the absorber according to another embodiment of the present invention. FIG. 4 is a schematic plan view of an absorber according to another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view taken along the line VV of the absorber shown in FIG. FIG. 6 is a schematic plan view showing an unfolded state of a disposable diaper containing the absorber of the present invention. FIG. 7 is a perspective view schematically showing the disposable diaper shown in FIG. 6 when it is deformed into a predetermined shape. FIG. 8 is a schematic view showing an example of a manufacturing apparatus for manufacturing an absorber according to an embodiment of the present invention. FIG. 9 is a schematic view showing an example of a manufacturing apparatus for manufacturing an absorber according to another embodiment of the present invention. FIG. 10A is a three-view view of an example of the embossed spin provided on the outer peripheral surface of the embossed roll. FIG. 10B is a plan view showing an example of the arrangement of embossed spins (convex portions) when the outer peripheral surface of the embossed roll is viewed in a plan view. FIG. 10C is a plan view showing another example of the arrangement of embossed spins (convex portions) when the outer peripheral surface of the embossed roll is viewed in a plan view. FIG. 11A is a plan view showing an example of the shape of the top surface of the top surface of the embossed spin (convex portion) when the outer peripheral surface of the embossed roll is viewed in a plan view. FIG. 11B is a plan view showing another example of the shape of the top surface of the top surface of the embossed spin (convex portion) when the outer peripheral surface of the embossed roll is viewed in a plan view. FIG. 11C is a plan view showing another example of the shape of the top surface of the top surface of the embossed spin (convex portion) when the outer peripheral surface of the embossed roll is viewed in a plan view. FIG. 11D is a plan view showing still another example of the shape of the top surface of the top surface of the embossed spin (convex portion) when the outer peripheral surface of the embossed roll is viewed in a plan view. FIG. 12 is a three-view view of another example of the embossed spin provided on the outer peripheral surface of the embossed roll. FIG. 13 is a schematic enlarged view of the nip between the embossed roll 805a and the anvil roll 805b of the squeezing device 805 in FIG. FIG. 14 is a graph of the density (g / cm ³ ) vs. rigidity (N) of the absorbers of Examples 1 to 3. FIG. 15 is a graph of the absorber density (g / cm ³ ) vs. rigidity (N) of Comparative Examples 1 to 3. FIG. 16 is a graph of the density (g / cm ³ ) vs. rigidity (N) of the absorbers of Comparative Examples 4 to 6.

Some of the embodiments of the invention related to the present invention are shown below.
[Aspect 1]
It contains an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer, and a core wrap covering the absorbent core, and includes a length direction, a width direction, a thickness direction, and a skin surface side surface and a non-skin surface. An absorber for absorbent articles with a side surface,
The absorber is at least one region having a super absorbent polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more, and is one of a skin surface side surface and a non-skin surface side surface. Or both have at least one region having a plurality of interspersed recesses and protrusions located between the plurality of recesses, and the length of the absorber when the absorber is viewed in a plan view. With respect to the portion of the convex portion located between any two adjacent recesses in the direction and the two adjacent recesses, the average value of the basis weight of the superabsorbent polymer in the two adjacent recesses is said. Less than the basis weight of the superabsorbent polymer in the convex part,
An absorber characterized by.
The absorber according to the first aspect is any adjacent 2 in the length direction of the absorber when the absorber is viewed in a plan view in at least one region having the above-mentioned predetermined superabsorbent polymer content and average density. For the portion of the convex portion located between the one concave portion and the two adjacent concave portions, the average value of the basis weight of the superabsorbent polymer in the two adjacent concave portions is the high water absorption in the convex portion. Since it is less than the basis weight of the sex polymer, the generation of hard spots is suppressed. Further, the absorber has a plurality of recesses formed on one or both of the skin surface side surface and the non-skin surface side surface in at least one region having the above-mentioned predetermined super absorbent polymer content and average density. As a result, the absorber is provided with rigidity, and since there are protrusions between the plurality of recesses, the absorbent article containing the absorber does not easily lose its shape when worn by the wearer. It is flexible and can provide a good feel and a good fit.

[Aspect 2]
The absorber according to the first aspect, wherein the average value of the basis weight of the superabsorbent polymer in the two recesses is 15% or more less than the basis weight of the superabsorbent polymer in the convex portion.
The absorber according to the second aspect is one in which the generation of hard spots is more reliably suppressed. Therefore, when the absorbent article containing the absorber is worn by the wearer, it does not easily lose its shape and can more reliably provide a good feel and a feeling of wearing.

[Aspect 3]
The area ratio of the plurality of recesses in the at least one region of the absorber in plan view is 25 to 65% independently on one or both of the skin surface side surface and the non-skin surface side surface. The absorber according to aspect 1 or 2.
When the area ratio of the recess is less than 25%, the effect of increasing the rigidity is not sufficient. If the area ratio of the recesses exceeds 65%, the rigidity of the absorber may become too high.

[Aspect 4]
The plurality of recesses each have a rectangular shape having an area of ² to 50 mm ^{2 in} a plan view, and the distance between adjacent recesses in the length direction of the absorber is 0.5 to 10 mm. The absorber according to any one of.
When the plan-view area of each recess is less than 2 mm ² , the contact area is small, so that the effect of rearranging the SAP to suppress the generation of hard spots is reduced and the risk of damaging the core wrap is increased. If the plan-view area of each recess exceeds 50 mm ² , the rigidity of the absorber may increase and the good touch may be impaired. If the distance between adjacent recesses in the length direction of the absorber is less than 0.5 mm, the movement of SAP is restricted, so that the effect of suppressing the generation of hard spots is not sufficient. When the distance between the adjacent recesses in the length direction of the absorber exceeds 10 mm, there is a region where the SAP cannot be rearranged, so that the effect of suppressing the generation of hard spots is reduced.

[Aspect 5]
The above aspect 1 to any one of the above aspects 1 to 4, wherein the absorber has a pair of deformation guiding portions extending in a predetermined direction, and the plurality of recesses are present between the pair of deformation guiding portions. Absorber.
The absorbent component including the absorber according to the fifth aspect fits the wearer's wearing portion and can prevent liquid leakage such as urine and menstrual blood.

[Aspect 6]
An absorbent article containing the absorber according to any one of the above aspects 1 to 5.
The absorbent article according to the sixth aspect does not easily lose its shape when worn by the wearer, and provides a good feel and a feeling of wearing.

[Aspect 7]
The method for producing an absorber for an absorbent article according to claim 1.
(A) A step of covering the absorption core with a core wrap to form a laminate having first and second surfaces corresponding to the skin surface side surface and the non-skin surface side surface of the absorber, respectively, and (b). A step of squeezing one or both of the first surface and the second surface of the laminate with an embossing roll rotating in the transport direction of the laminate to form the absorber while conveying the laminate.
The embossed roll has at least one region provided with a plurality of scattered protrusions on its outer peripheral surface.
The plurality of interspersed convex portions on the outer peripheral surface of the embossed roll each include a base portion and a hemispherical or n-side pyramidal trapezoidal shape (n is an integer of 4 or more).
In the step (b), when the top comes into contact with the surface of the laminate according to the rotation of the emboss roll, the angle formed by the side surface of the top and the laminate on the upstream side in the rotation direction of the emboss roll is 0 to 0. Within the range of 60 degrees,
Manufacturing method of absorber.
According to the method for producing an absorber according to the seventh aspect, the plurality of convex portions provided on the outer peripheral surface of the embossed roll used in the step (b) are hemispherical or n-sided pyramidal trapezoidal shape (n is 4 or more). It has a top (tip) of (integer) and is thin and not sharp, so the core wrap is not easily damaged during the squeezing process. Further, since the plurality of protrusions of the embossed roll have a structure in which the apex is bonded to the outer peripheral surface of the embossed roll via the base, the laminate is pressed deeper with a larger contact area ratio in the thickness direction thereof. be able to. After the top of the convex portion of the embossed roll comes into contact with the surface of the laminate, the top of the convex portion presses the laminate in the thickness direction while pushing away the particles of the superabsorbent polymer, so that the laminate is pressed by the convex portion. At the same time as it is compacted, some of the superabsorbent polymer particles move around the recesses. Therefore, in the portion (concave portion) squeezed by the convex portion of the embossed roll according to the present invention, the basis weight of the superabsorbent polymer is reduced as compared with that before squeezing by the embossed roll, and the portion (concave portion) adjacent to the squeezed portion (concave portion). In the portion (convex portion), the basis weight of the superabsorbent polymer increases as compared with that before pressing with embossed roll. That is, the squeezing with the embossed roll causes the rearrangement of the superabsorbent polymer particles, and the generation of hard spots is suppressed. Furthermore, if hard spots due to the non-uniform distribution of superabsorbent polymer particles are present in the absorption core before being squeezed by the embossed roll, the hard spots are eliminated or reduced by the above step (b). be able to.

[Definition of terms]
The definitions of the terms used in the present specification will be described.
In the present specification, unless otherwise specified, "an object (for example, an absorbent article, an absorber, etc.) placed on a horizontal plane in an unfolded state is viewed from the upper side in the vertical direction in the thickness direction of the object. Is simply called "planar view".
The "width direction WD" refers to the "short direction (short direction) of the length of the vertically long object in the plan view", and the "length direction LD" refers to the "length of the vertically long object in the plan view". The "long direction (longitudinal direction)" and the "thickness direction TD" refer to the "vertical direction (that is, the thickness direction of the object) with respect to the unfolded state on the horizontal plane", and their widths. The direction WD, the length direction LD, and the thickness direction TD are in a relationship orthogonal to each other.
Vertically elongated object (e.g., an absorbent article, the absorbent body, etc.) in the width direction W of the inner side in the "width direction relatively proximal side with respect to the width direction central axis C _L extending in the longitudinal direction L called "in the width direction W of the vertically elongated object, the relatively distal called" outward in the width direction "with respect to the width direction central axis C _L. Further, in the length direction L of the vertically long object, the proximal side relative to the length direction central axis C _W extending in the width direction W is referred to as the "inner side in the length direction", and the vertically long object. In the length direction L of an object, the distal side relative to the central axis C _{W in the} length direction is referred to as the "outer side in the length direction".
In the thickness direction TD of the absorbent article, "the side relatively proximal to the wearer's skin surface when wearing the absorbent article" is called "skin surface side", and "the wearer when wearing the absorbent article". The "distal side relative to the skin surface" is called the "non-skin surface side".
With respect to the absorber, the "recess" refers to a portion of the absorber that is consolidated in the thickness direction.
For any two adjacent recesses in the length direction of the absorber, the "average value of the basis weight of the superabsorbent polymer" is the superabsorbent polymer content of 40 to 85% by mass of the absorber and 0.15 g. in / cm ³ region having the above average density means the average value of the basis weight of superabsorbent polymer for the two recesses adjacent in the length direction of the 10 pairs that are randomly sampled.
For the portion of the convex portion located between any two adjacent concave portions in the length direction of the absorber, the "superabsorbent polymer basis weight" is 10 pairs of lengths randomly sampled as described above. It means the average value of the basis weight of the convex portion located between two concave portions adjacent to each other in the direction.
Regarding the absorber, "the portion of the convex portion located between two adjacent concave portions in the length direction of the absorber" is the open end of any two adjacent concave portions in the length direction of the absorber. It means a region surrounded by contour lines facing each other and two straight lines connecting the corresponding ends in the width direction of these contour lines.
For the absorber, the "region having a plurality of scattered recesses" means a region surrounded by the shortest envelope connecting the outermost edges of the plurality of scattered recesses.

A preferred embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that the drawings may not be drawn in the same scale and shape as the actual components in order to facilitate understanding of the present invention. The same reference number represents the same element.
[Absorber]
An absorber according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic plan view showing an embodiment of an absorber, taking an absorber for disposable diapers as an example. As shown in FIG. 1, the absorber 100 has a length direction LD, a width direction WD, and a thickness direction TD (not shown) perpendicular to the LD and WD, and has an absorption core 110 and an absorption core 110. Includes a core wrap 120 that covers the outer circumference of the. FIG. 1 shows the skin-side surface when the absorber 100 is worn by the wearer in a state of being incorporated in a disposable diaper, and shows the wearer's ventral side, inseam ventral side, inseam dorsal side, and dorsal side. The ventral region A1, the inseam ventral region A2, the inseam dorsal region A3, and the dorsal region A4 of the absorber 100 that abuts on the side skin surface are shown. In these regions A1 to A4, there are regions A1c, A2c, A3c and A4c in which a plurality of recesses 140 are arranged at predetermined intervals in the length direction LD and the width direction WD. The absorber 100 is further provided with notches 112aR, 112aL, 112bR, 112bL, 112cR and 112cL at the end edge of the absorption core 110. The plurality of recesses 140 scattered in the regions A1c, A2c, A3c and A4c are portions that are compacted by squeezing the corresponding portions of the absorption core and the core wrap in the thickness direction of the absorber 100, and are scattered. It is a portion thinner than the flat portion (hereinafter, referred to as “outer edge portion”) 130 of the outer edge of the region having the recess 140 of the above. The absorber 100 is recessed in the regions A1c to A4c with respect to the surface of the outer edge portion 130 on the skin surface side, and the thickness of the absorber in the regions A1c to A4c is smaller than the thickness of the outer edge portion 130. The thickness of the region having a plurality of scattered recesses and the thickness of the outer edge portion 130 are the thickness measured by the PEACOCK dial thickness gauge J-B (meter diameter: 50 mm, pressure: 294 Pa) manufactured by Ozaki Seisakusho. Is. FIG. 1 shows an embodiment in which a plurality of recesses 140 are arranged at predetermined intervals in the length direction LD and the width direction WD in the regions A1c, A2c, A3c and A4c of the surface side surface of the absorber 100. However, the absorber of the present invention has at least one region having a superabsorbent polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more, and each of the at least one region has. Independently, the absorber of the present invention has a plurality of concave portions scattered on one or both of the skin surface side surface and the non-skin surface side surface, and convex portions located between the plurality of concave portions. It is not limited to the embodiment illustrated in 1. Therefore, the plurality of recesses as shown in FIG. 1 may be provided not on the skin surface side surface of the absorber but on the non-skin surface side surface, or on both the skin surface side surface and the non-skin surface side surface. ..

Absorption core 110 contains at least hydrophilic fibers and particulate superabsorbent polymer. Examples of hydrophilic fibers include cellulosic water-absorbent fibers such as pulp. In addition, hydrophilic synthetic fibers may be included. Examples of superabsorbent polymers include superabsorbent polymers that are generally used as absorbers for absorbent articles such as starch-based, cellulosic-based, and synthetic polymer-based polymers. In the consolidated portion of the absorber, the hydrophilic fiber density of the absorption core is higher than the hydrophilic fiber density of the absorption core in the non-consolidated portion.

The core wrap 120 is not particularly limited as long as it has a function of retaining liquid permeability and a constituent material of the absorbing core in the absorbing body, but is not particularly limited, but is limited to tissues, non-woven fabrics, for example, air-through non-woven fabrics, spun-pound non-woven fabrics, spunbonds / melt blown / spunbonds (SMS). ) Non-woven fabric and the like can be mentioned. The basis weight is preferably 10 to 30 g / m ² in both cases where the core wrap is made of tissue paper and the core wrap is made of non-woven fabric.

When the superabsorbent polymer content in at least one region where the plurality of interspersed recesses are provided is less than 40% by mass, the absorber keeps the absorption performance of the absorber at an appropriately high level. It is difficult to reduce the thickness of the SAP particles, and when the content of the super absorbent polymer exceeds 85% by mass, the SAP particles may give a discomfort to the wearer due to the jerky touch. Further, when the content of the super absorbent polymer exceeds 85% by mass, a gel blocking phenomenon may occur and the liquid absorption performance may be deteriorated. When the average density in at least one region where the plurality of interspersed recesses are provided is less than 0.15 g / cm ³ , appropriate rigidity is realized within the range of the above superabsorbent polymer content. It is difficult to do. In at least one region having a superabsorbent polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more of the absorber of the present invention, the area ratio of the plurality of recesses in a plan view is preferable. Is 25-65%. When the area ratio of the recess is less than 25%, the effect of increasing the rigidity is not sufficient. If the area ratio of the recesses exceeds 65%, the rigidity of the absorber may become too high. For any region of the absorber, the super absorbent polymer content is included in each sample after cutting five samples of a predetermined length and width from the absorption core (for example, 20 mm × 50 mm) and measuring the mass of each sample. The superabsorbent polymer particles are selected, the total mass of the superabsorbent polymer contained in each sample is measured, and the ratio of the mass of the superabsorbent polymer to the mass of each sample can be calculated. For an arbitrary region of the absorber, the average density is determined by cutting out five samples having a predetermined length and width from the absorber (for example, 20 mm × 50 mm), measuring the mass of each sample, and using this measured value as described above. It can be obtained by the average value obtained by dividing the thickness obtained by the measurement method of (1) and the area of the sample by the volume of the sample obtained.

As will be described below with reference to FIG. 2, when the skin surface side surface having the plurality of recesses 140 dotted with the absorber 100 is viewed in a plan view, the recesses 140 are L1 in the width direction WD of the absorber. It has an opening end 141 having a dimension of L2 in the longitudinal LD, and each recess has a bottom 142 having an dimension of L3 in the width WD of the absorber and L4 in the longitudinal LD. L1 is preferably 2 to 25 m, more preferably 2 to 8 mm, and even more preferably 3 to 5 mm. L2 is preferably 1 to 25 mm, more preferably 1.5 to 6 mm, still more preferably 2 to 4 mm. The area S (= L1 × L2) of the opening end 141 of the recess is preferably 2 to 50 mm.², More preferably 3 to 30 mm², More preferably 5 to 20 mm²Is. The shortest distance L5 between the opening ends of the adjacent recesses in the width direction WD of the absorber is preferably 0.5 to 10 mm, more preferably 1 to 6 mm, still more preferably 2 to 5 mm. The shortest distance L6 between the opening ends of the adjacent recesses in the length direction LD of the absorber is preferably 0.5 to 10 mm, more preferably 1 to 6 mm, still more preferably 2 to 5 mm. Here, L1 to L4 and S have a superabsorbent polymer content of 40 to 85% by mass and 0.15 g / cm, respectively, of the absorber.³It means the average value of L1 to L4 and S of 10 recesses randomly sampled in the region having the above average density. L5 and L6 are between the open ends of adjacent recesses in 10 pairs of widthwise WDs and lengthwise LDs randomly sampled in the region of the absorber having the above-mentioned superabsorbent polymer content and average density, respectively. It means the average value of the shortest interval. The "convex portion" located between the two adjacent recesses is the contour lines 141a and 141b of the open ends of the two adjacent recesses facing each other in the length direction of the absorber and the width direction of these contour lines. It is a region surrounded by two straight lines connecting the corresponding both ends of the above, and is shown by reference numeral 146 in FIG. In FIG. 2, the contour lines 141a and 141b facing each other at the opening ends of two adjacent recesses correspond to the opposite sides of the opening ends of the two adjacent recesses. When the absorber is viewed in a plan view, the open end of the recess can be a circle such as a perfect circle, an oval, or an ellipse, or a polygon such as a quadrangle, a pentagon, a hexagon, a heptagon, or an octagon. Further, as will be described below with reference to FIG. 3A, the recess 140 has a convex portion located between the plurality of recesses, that is, a surface region between the open ends of the plurality of recesses as a reference surface in the thickness direction of the absorber. It is recessed in TD at a depth of d. The average value of the depth d, that is, the average depth is preferably 0.5 to 5 mm, more preferably 1.5 to 3.5 mm. Here, the "average depth" is a superabsorbent polymer content of 40 to 85% by mass of the absorber and 0.15 g / cm. ³It means the average value of the maximum depths of 10 recesses randomly sampled in the region having the above average density. The average value of L1 to L6 and S and the depth d of the recess are determined by using a laser displacement meter (for example, a high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Co., Ltd.). It can be measured by measuring by a non-contact method.

Each notch 112aR~112cR and 112aL~112cL has a shape that tapers toward the axis _{C L,} by notch has such a shape, the length in the absorbent core There is a difference in rigidity in the direction, and it is easy to bend the absorber along the bending guide lines BLa, BLb and BLc where the width of the absorption core is locally narrow. As a result, when the absorber 110 is deformed and three-dimensionalized, the bending range in which the ends of the absorber do not interfere with each other can be widened, so that the absorber is more easily deformed due to the predetermined shape. The cutout portion may have an arbitrary shape such as a polygonal shape or an arc shape as long as the interference between the ends of the absorber can be prevented. The absorption core may not be provided with a notch. A notch may be provided in the core wrap constituting the absorber. The shape and size of the region where the plurality of recesses 140 are scattered, the shape and size of the notch, the shape and size of the absorption core, and the shape and size of the core wrap are not limited to the embodiment shown in FIG. A region in which the absorber has the above-mentioned predetermined superabsorbent polymer content and average density, and is provided with a plurality of recesses as described above on one or both of the skin surface side surface and the non-skin surface side surface. When there are two or more recesses, the positions, shapes and dimensions of the plurality of recesses 140 in these areas, and the spacing between adjacent recesses may be the same or different from each other in the two or more regions. ..

FIG. 2 is an enlarged view of the region B of the absorber 100 shown in FIG. In FIG. 2, with respect to the recess 140 when the skin surface side surface having a plurality of recesses 140 dotted with the absorber 100 is viewed in a plan view, the dimension of the absorber 100 in the width direction WD is L1 and the dimension in the length direction LD is L2. The opening end 141 is shown, and the bottom 142 is shown where the absorber has a dimension of L3 in the width direction WD and a dimension of L4 in the length direction LD. The distance between the opening ends of the adjacent recesses in the width direction WD of the absorber is indicated by L5, and the distance between the opening ends of the adjacent recesses in the length direction LD of the absorber is indicated by L6.

FIG. 3A is a schematic cross-sectional view taken along line III-III of region B of the absorber 100 shown in FIG. In FIG. 3A, the particles of the superabsorbent polymer are indicated by reference number 114, the hydrophilic fibers are indicated by reference number 116, and the protrusions located between the plurality of recesses 140 are indicated by reference number 145. ing. The plurality of recesses 140 are recessed at a depth d in the thickness direction TD of the absorber with the convex portion located between the plurality of recesses, that is, the surface region between the open ends of the plurality of recesses as a reference surface. The bottom portion 142 is composed of 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. To. The inclined surface 142b is preferably inclined at 10 to 60 degrees with respect to the in-plane direction of the absorber. In the absorber of the present invention, the superabsorbent polymer having the above-mentioned predetermined high water-absorbent polymer content and average density is absorbed by the basis weight of the superabsorbent polymer in each recess in the region provided with a plurality of scattered recesses. It is less than the basis weight of the superabsorbent polymer in the portion of the convex portion adjacent to each concave portion in the length direction of the body and having the same planological area as each concave portion. That is, as schematically shown in FIG. 3A, in the length direction LD and the width direction WD of the absorber, the superabsorbent polymer particles 114 have a basis weight higher than the basis weight of the superabsorbent polymer particles in the recess 140. It exists in the region 145a of the convex portion 145 adjacent to the concave portion 140, that is, on the outer edge of the concave portion 140. Therefore, the absorber of the present invention suppresses the coalescence or aggregation of superabsorbent polymer particles in the recesses that can cause hard spots.

FIG. 3B shows a plurality of recesses interspersed on both the skin-side surface and the non-skin-side surface in at least one region of the absorber 100 having the above-mentioned predetermined superabsorbent polymer content and average density. It is a schematic cross-sectional view which shows another embodiment of the absorber of this invention which has been made. In FIG. 3B, a plurality of recesses 140 having the same shape and dimensions as the recesses 140 provided on the non-skin surface side surface, that is, on the opposite side of the convex portions 145 between the plurality of recesses 140 provided on the skin surface side surface at predetermined intervals. The recess is indicated by reference number 140', and the convex portion located between the plurality of recesses 140'is indicated by reference number 145'. The recess 140'is recessed at a depth d'in the thickness direction TD of the absorber with the top surface of the convex portion 145'located between the adjacent recesses as a reference surface. The bottom portion 142'has a bottom surface 142a'that is substantially parallel to the in-plane direction of the absorber and an inclined surface 142b that extends along the outer edge of the bottom surface 142a'and is inclined with respect to the in-plane direction of the absorber. Consists of'and. The inclined surface 142b'is preferably inclined at 10 to 60 degrees with respect to the in-plane direction of the absorber. Reference number 145a is a region of the convex portion 145'adjacent to the concave portion 140' where the superabsorbent polymer particles 114 exist at a basis weight higher than the basis weight of the superabsorbent polymer particles in the concave portion 140'. It is indicated by'. With respect to the recess 140'when the non-skin surface side surface having a plurality of recesses 140 scattered in the absorber 100 is viewed in a plan view, the opening end 141'and the bottom 142' in the width direction WD and the length direction LD of the absorber The dimensions and the distance between the open ends of the adjacent recesses in the width direction WD and the length direction LD of the absorber are within the above range for the skin surface side surface with the plurality of recesses 140 provided on the skin surface side surface. It can be selected independently and may be the same as or different from the plurality of recesses 140 provided on the skin surface side surface. Further, at least one of the plurality of recesses 140 provided on the skin surface side surface may at least partially overlap the plurality of recesses provided on the non-skin surface side surface and the thickness direction TD of the absorber. ..

FIG. 4 is a plan view schematically showing an absorber according to another embodiment of the present invention. Absorber 100 shown in FIG. 4 '(in the embodiment, the direction along the length L of the absorbent article) predetermined direction symmetrically with respect to the axis C _L having a pair of deformation introducing portion 150R and 150L extending Except for this, it has the same structure as the absorber of the embodiment shown in FIG. In the embodiment of the absorber shown in FIG. 4, the deformation guiding portions 150R and 150L are provided on the outer side in the width direction. The pair of deformation induction portions 150R and 150L can be low basis weight regions having a basis weight lower than the peripheral regions of the deformation induction portions 150R and 150L, respectively, whereby the absorber, and thus the absorber, incorporates the absorber. The sex article is likely to bend around the deformation inducing portion. The shapes of the pair of deformation guiding portions 150R and 150L can be set so that the absorbent article in which the absorber is incorporated can easily follow the three-dimensional shape of the wearing portion of the wearer. The absorber may include a recess formed continuously or discontinuously in the deformation inducing portion so that the absorbent article containing the absorber has a better fit to the wearer. The basis weight of the deformation guiding portion is not particularly limited, but is preferably 30 to 80% by mass of the basis weight of the outer edge portion 130.

FIG. 5 is a diagram for explaining one embodiment of the pair of deformation guiding portions 150R and 150L, and is a schematic cross-sectional view taken along the line VV of the absorber 100'shown in FIG. FIG. 5 shows an example in which the deformation guiding portions 150R and 150L are composed of a low basis weight region. In the embodiment shown in FIG. 5, the low basis weight regions constituting the deformation induction portions 150R and 150L each have a width of WR and WL in the width direction WD, and have a bottom portion Ba and inclined portions Sl on both sides thereof. .. In the low basis weight region, the basis weight of the bottom Ba is the smallest, and in the inclined portion Sl, the basis weight gradually increases as the distance from the bottom Ba is increased. The low basis weight region can be formed, for example, according to the methods described in JP-A-2010-233839 and JP-A-2016-123636 of the same applicant.

FIG. 6 is a schematic plan view showing a developed state of a disposable diaper containing the absorber of the present invention, and FIG. 7 schematically shows the disposable diaper shown in FIG. 6 when deformed into a predetermined shape. It is a perspective view. As shown in FIG. 6, the disposable diaper 1 has a shape in which the outer shape is long in the length direction LD in a plan view, and the substantially central portion of the length direction LD is directed toward the inside of the width direction WD. It has a narrow, roughly hourglass-shaped shape. In the present invention, the outer shape of the absorbent article is not limited to such an outer shape, as long as the length dimension in the length direction L is longer than the width dimension in the width direction W. It can have an arbitrary vertically long shape (for example, a rectangle, an ellipse, a gourd, etc.) according to various uses. The disposable diaper 1 according to the present embodiment includes a liquid-permeable front surface sheet 2, a liquid-impermeable back surface sheet 3, and an absorber 4 of the present invention disposed between these sheets. .. Further, the disposable diaper 1 is a hydrophobic or water-repellent side sheet 5 or 5 disposed on the skin surface side of the surface sheet 2 to form a pair of leak-proof walls, and the tip of the WD in the width direction of the side sheet. On the side, it has elastic members 6 and 6 extending in the length direction LD. In the disposable diaper 1 shown in FIG. 7, one end side of the length direction LD located in the lower part of FIG. 6 is the ventral side covering the wearer's abdomen, and the other end side of the length direction L located above the wearer is the wearer. The dorsal side that covers the back (buttocks). Further, the disposable diaper 1 according to the present embodiment is a so-called tape-type disposable diaper that is worn on the wearer by using the tape fastener 7 when worn. The disposable diaper according to the embodiment of the absorbent article of the present invention is not limited to the tape-type disposable diaper, and may be another type of disposable diaper such as a pants-type disposable diaper.

In the present embodiment, the surface sheet 2 is disposed on the skin surface side of the absorber 4, and is a liquid that quickly absorbs or permeates liquid excrement such as urine from the wearer and transfers it toward the absorber 4. It is a permeable sheet-like member. In the present embodiment, the surface sheet 2 is formed long in the length direction L of the disposable diaper 1. As the surface sheet 2, any liquid permeable sheet such as a non-woven fabric, a woven fabric, a synthetic resin film having liquid permeable holes formed therein, or a net-like sheet having a mesh can be used. Among these, liquid permeable sheets can be used. From the viewpoint of properties, flexibility, touch, etc., it is preferable to use a non-woven fabric. The back sheet 3 is arranged on the non-skin surface side of the disposable diaper 1 and is a liquid-impermeable sheet-like member that prevents liquid excrement discharged from the wearer from leaking to the outside of the disposable diaper 1. Is. The back surface sheet 3 is joined to each other with the front surface sheet 2 and the side sheets 5 and 5 sandwiched between the absorber 4. For this bonding, any bonding means such as bonding with a hot melt type adhesive or bonding by various embossing treatments can be used. The back sheet is, for example, a non-woven fabric that has been waterproofed, a synthetic resin film such as polyethylene or polypropylene, a composite sheet of a non-woven fabric and a synthetic resin film, a spunbond / melt blow / spunbond (SMS) composite non-woven fabric, or any other liquid-free material. A permeable sheet can be used.

FIG. 8 illustrates an example of a manufacturing apparatus 800 used for manufacturing an absorber according to an embodiment of the present invention, which has a plurality of recesses scattered on one of a skin surface side surface and a non-skin surface side surface. It is a schematic diagram for doing. In the present specification, the direction along the material or product transport direction F is also referred to as the MD direction, and the direction orthogonal to the MD direction on the horizontal plane (that is, the width direction of the production line) is referred to as the CD direction. The direction orthogonal to the CD direction (that is, the vertical direction of the production line) is called the TD direction. The manufacturing apparatus 800 includes a transport tube 801 for transporting an absorbent material containing the opened hydrophilic fiber 8F and a particulate superabsorbent polymer 8S, and a first laminate which is a precursor of the absorption core of the absorber. A rotatable suction drum 802 forming the 811, a winding roll 804 for the core wrap continuum for unwinding the long core wrap continuum 812 covering the outer peripheral surface of the first laminated body 811, and a squeezing device 805. And. The squeezing device 805 is for forming a plurality of recesses 140 scattered on the skin surface side surface of the absorber, and a plurality of embossed spins (convex portions) protruding outward in the radial direction of the roll are shown in FIG. A pair of rolls composed of an embossed roll 805a arranged on the outer peripheral surface and an anvil roll 805b having a smooth outer peripheral surface corresponding to the positions and shapes of the regions A1c to A4c of the absorber 100 shown are provided. A plurality of concave mold members 803 arranged at regular intervals along the circumferential direction are provided on the outer peripheral surface of the suction drum 802, and the absorbent material is sucked and laminated in the concave mold member 803. To. The first laminated body 811 formed by the mold member 803 is transferred from the suction drum onto the core wrap continuous body, and then covered with the core wrap continuous body to form the second laminated body 813. The second laminate 813 is conveyed to the squeezing device 805 and squeezed by the squeezing device 805. In FIG. 8, the laminate passing through the nip between the embossed roll 805a and the anvil roll 805b of the squeezing device 805 is shown by reference number 814. The particulate superabsorbent polymer that can be used to form the precursor of the absorption core may be any superabsorbent polymer that is generally used for an absorber for an absorbent article. The particulate superabsorbent polymer preferably has a particle size in the range of 150 μm to 850 μm and has a particle number percentage of 95% or more.

Therefore, when the absorber is manufactured using the manufacturing apparatus 800, the first laminate 811 is formed by laminating an absorbent material containing the hydrophilic fiber 8F and the superabsorbent polymer particles 8S. And the second step of covering the first laminated body 811 with the core wrap continuous body 812 to form the second laminated body 813, and pressing the second laminated body 813 in the thickness direction by the pressing device 805. Then, the third step of forming the third laminated body 815 by embossing is sequentially carried out. A cutting device for forming a single absorber by cutting a third laminated body 815 embossed by the squeezing device 805 into a desired shape on the downstream side of the squeezing device 805 in the transport direction F (FIG. (Not shown) can be provided. Further, a front sheet laminating device (not shown) for supplying the front surface sheet continuum to the upper surface of the absorber and laminating it to the manufacturing apparatus 800, and a back surface sheet laminating device for supplying and laminating the back surface sheet continuous body to the lower surface of the absorber. By providing a device such as (not shown), an absorbent article such as a disposable diaper can be manufactured in-line.

FIG. 9 is a schematic for explaining an example of a manufacturing apparatus for manufacturing an absorber according to an embodiment of the present invention, which has a plurality of recesses scattered on both the skin surface side surface and the non-skin surface side surface. It is a figure. Similar to the manufacturing apparatus shown in FIG. 8, the manufacturing apparatus 800 ′ includes a transport pipe 801 for transporting an absorbent material containing the opened hydrophilic fiber 8F and the superabsorbent polymer 8S, and the absorbing core of the absorber. For a rotatable suction drum 802 forming the first laminated body 811 which is a precursor and a core wrap continuous body for unwinding a long core wrap continuous body 812 covering the outer peripheral surface of the first laminated body 811. A second squeeze including an unwinding roll 804, a squeezing device 805 (first squeezing device), and a pair of rolls composed of an embossed roll 805a'and an anvil roll 805b' having a smooth outer peripheral surface. The device 805'is provided. The embossed roll 805a'and the anvil roll 805b' of the second squeezing device 805'are the same as the anvil roll 805b'and the embossed roll 805a of the first squeezing device 805 for the laminates 811, 813, 815 and 817, respectively. On the side. In the manufacturing apparatus 800'of the embodiment shown in FIG. 9, a plurality of recesses scattered on the skin surface side of the absorber are formed by the squeezing apparatus 805 (first squeezing apparatus), and the squeezing apparatus 805'(second squeezing apparatus) is formed. A squeezing device) is used to form a plurality of recesses scattered on the non-skin surface side of the absorber. In FIG. 9, the laminate passing through the nip between the embossed roll 805a'and the anvil roll 805b' of the squeezing device 805'is shown by reference number 816, with reference number 816 on the skin-side surface and the non-skin-side surface. The embossed laminate is indicated by reference numeral 817. When the absorber is manufactured by using the manufacturing apparatus 800', the first laminate 811 is formed by laminating an absorbent material containing the hydrophilic fiber 8F and the highly water-absorbent polymer particles 8S. The second step of covering the first laminated body 811 with the core wrap continuous body 812 to form the second laminated body 813, and the second step of forming the second laminated body 813, and the thickness direction of the second laminated body 813 by the first pressing device 805. The third step of forming the third laminated body 815 by squeezing and embossing the third laminated body 815 and the third laminated body 815 being squeezed in the thickness direction by the second squeezing device 805'to emboss. The fourth step of forming the fourth laminated body 817 by the application is sequentially carried out.

FIG. 10A is a three-view view of an example of an embossed spin (convex portion) provided on the outer peripheral surface of the embossed roll. The embossed spin 90 shown in FIG. 10A is composed of a base 91 and a quadrangular pyramid-shaped top 92, and is twice symmetrical with respect to the central axis in the directions perpendicular to the MD direction and the CD direction. The base 91 extends radially outward of the roll from the smooth reference plane (not shown) of the embossed roll, and the top 92 extends radially outward of the roll from the top surface of the base. The top 92 of the embossed spin illustrated in FIG. 10A has a quadrangular pyramid shape, but the shape of the top 92 is a hemispherical or semi-rotating elliptical shape, a truncated cone shape, a pentagonal pyramid, a hexagonal pyramid, or a seven-sided pyramid. , Can be a polygonal pyramid shape such as an octagonal truncated cone. The base 91 of the embossed spin illustrated in FIG. 10A has a quadrangular prism or a quadrangular pyramid shape, but the shape of the base 91 is, for example, a cylindrical or conical trapezoidal shape, a pentagonal prism, a hexagonal pillar, or seven, depending on the bottom surface of the top. It can be a polygonal pillar shape such as a prism or an octagonal pillar, or a polygonal pyramid shape such as a pentagonal pyramid, a hexagonal pyramid, a seven-sided pyramid, or an octagonal pyramid. In the embossed spin illustrated in FIG. 10A, the top 92 is the top TS, the facing side surface SS1 parallel to the CD direction, the facing side surface SS2 parallel to the MD direction, the bottom surface BS1 and the height h.₁The base has the same top surface, bottom surface BS2 and height h as the bottom surface BS1 of the top.₂Have. The top surface TS, bottom surface BS1 and bottom surface BS2 are parallel to each other. The top surface TS of the top portion 92 has the length of LT1 in the CD direction and the length of LT2 in the MD direction, and the bottom surface BS1 of the top portion 92 and the top surface of the base have the length of LB1 in the CD direction and the length in the MD direction. It has a length of LB2. In FIG. 10A, for simplicity, the base 91 is shown as a rectangular parallelepiped, but the tilt angle α in the MD and CD directions.₁， Β₁(That is, the angle formed by the side surface SS1 and the bottom surface BS1 of the top 92 and the angle formed by the side surface SS2 and the bottom surface BS1 of the top 92) are the inclination angles α, respectively.₂， Β₂Under the condition that it is smaller than (that is, the angle between the side surface of the base parallel to the CD direction and the bottom surface of the base and the angle between the side surface of the base parallel to the MD direction and the bottom surface of the base), the base 91 is the bottom surface of the top 92. It can be a cylinder or truncated cone shape having a common top surface, or an n-prism or n-square pyramidal cone (n is an integer of 4 or more). Tilt angle α₁Is preferably 10 to 60 degrees, and the inclination angle β₁Is preferably 10 to 60 degrees. α₂And β₂When is 90 degrees, the embossed spin 90 can be provided at a higher density on the outer peripheral surface of the embossed roll, so that α₂And β₂Is preferably 90 degrees. Top height h₁And the height of the base h ₂Total h (= h)₁+ H₂) Is 1 to 20 mm, preferably 2 to 4 mm. When h is less than 1 mm, the effect of squeezing the laminate in the thickness direction is not sufficient, so that the term for eliminating or reducing hard spots is not sufficient. An embossed roll having a large number of embossed spins in which h exceeds 20 mm has a problem of high manufacturing cost. Top height h₁Is preferably 0.2 to 2 mm. Base height h₂Is preferably 1.8 to 3.8 mm. The length LB1 of the bottom surface BS1 of the top in the CD direction is preferably 2 to 25 mm, more preferably 2 to 8 mm, still more preferably 3 to 5 mm. The length LB2 of the bottom surface BS1 of the top in the MD direction is preferably 1 to 25 mm, more preferably 1.5 to 6 mm, still more preferably 2 to 4 mm. The length LT1 of the top surface TS of the top surface in the CD direction is preferably 1 to 20 mm, more preferably 2 to 5 mm, and further preferably 2.5 to 5 mm. The length LT2 of the top surface TS of the top portion in the MD direction is preferably 0.5 to 15 mm, more preferably 1 to 5 mm, still more preferably 1 to 3 mm. The area of the bottom surface BS2 of the base is preferably 2 to 50 mm.², More preferably 3 to 30 mm², More preferably 5 to 20 mm²Is. The distance between adjacent embossed spins in the CD and MD directions, that is, the shortest distances D1 and D2 on the side surface of the base of the adjacent embossed spins, is preferably 0.5 to 13 mm, more preferably 1 to 6 mm, still more preferably. It is 1 to 5 mm. LT1, LT2, LB1, LB2, h₁, H₂, Α₁, Β₁, Α₂, Β₂, D1 and D2, and the size and shape of BS2 can be determined according to the shape, size and spacing of the recesses to be formed in the absorber, the radius of the embossing roll, and the like.

10B and 10C are plan views illustrating the arrangement of embossed spins (convex portions) when the outer peripheral surface of the embossed roll is viewed in a plan view. For the sake of simplicity, the base of the embossed spin is omitted in FIGS. 10B and 10C. FIG. 10B shows an embodiment in which a plurality of embossed spins have a quadrangular pyramid-shaped top and are arranged in parallel in the CD direction and the MD direction at predetermined intervals D1 and D2, respectively. FIG. 10C shows an embodiment in which a plurality of embossed spins have an octagonal pyramidal top and are staggered, i.e., staggered. In FIG. 10C, the distance between adjacent tops in the CD direction is indicated by D1, and the distance between adjacent tops in the MD direction is indicated by D2. The spacing between adjacent embossed spins is determined according to the spacing between adjacent recesses in the absorber. The plurality of embossed spins may be arranged in a sequence other than the sequences shown in FIGS. 10B and 10C as long as the effects of the present invention are not impaired. For example, the embossed spins can be arranged in a regular or irregular arrangement so as to satisfy the area ratio of the embossed spins of 25 to 65% when the outer peripheral surface of the embossed spins is viewed in a plan view. It is preferable that the embossed spins are regularly arranged at regular intervals in order to prevent the appearance of the absorber and the occurrence of locally high-rigidity portions.

11A to 11D are plan views illustrating the shape of the top surface of the top of the embossed spin (convex portion) when the outer peripheral surface of the embossed roll is viewed in a plan view. The top surface of the top has a rectangular shape with four corners at right angles as shown in FIG. 11A, a shape with R chamfered corners as shown in FIG. 11B, and a C chamfered corner as shown in FIG. 11C. Can have a shaped shape. The top surface of the top may be oval, as shown in FIG. 11D. The apex can be hemispherical or semi-spheroidal. When the top surface of the embossed spin top has a shape in which the corners are R-chamfered or a corner is C-chamfered as shown in FIGS. 11B to 11D, refer to FIG. However, as described below, when embossing the laminate, when the top of the embossed spin hits the laminate, the squeezing pressure on the laminate can be dispersed and the core wrap can be prevented from being damaged.

FIG. 12 schematically shows a further example of embossed spin. The embossed spin of the embodiment shown in FIG. 12 is composed of a base portion 1110 and a top portion 1120, the base portion 1110 is an octagonal columnar shape, and the top portion 1120 has a top surface TS and R chamfer having a shape corresponding to a rectangle whose four corners are R-chamfered. has been side SS, shape corresponding to the C chamfered rectangle (i.e. octagonal) has a bottom surface BS1 and the height h ₁ of the top surface of the base is common with the bottom surface BS1 in the top, bottom BS2 and the height h ₂ Has. The top surface TS of the top has a length of LT1 in the CD direction and a length of LT2 in the MD direction, and the bottom surface BS1 of the top has a length of LB1 in the CD direction and a length of LB2 in the MD direction. In FIG. 11, for simplification, the base 91 is shown as an octagonal prism, but in the MD direction and the CD direction, the angles α ₁ and β ₁ formed by the side surface of the top 92 and the bottom surface BS ₁ are the side surface and bottom surface of the base. Under the condition that the angles α ₂ and β ₂ are smaller than the angles α ₂ and β ₂ formed by the above, the base 91 shall be an n-square prism or an n-side pyramid trapezoid shape (n is an integer of 4 or more) having a top surface common to the bottom surface of the top 92. Can be done. An embossed roll having a large number of embossed spins in which h exceeds 20 mm has a problem of high manufacturing cost. When the pressing step is carried out using an embossed roll having a plurality of embossed spins illustrated on the outer peripheral surface, the effect of preventing damage to the core wrap when the top of the embossed spins comes into contact with the laminate is further improved. It can be further enhanced.

FIG. 13 is a schematic enlarged view of the nip between the embossed roll 805a and the anvil roll 805b of the squeezing device 805 in FIG. FIG. 13 shows an embossed spin (convex portion) in which one side of the laminated body 814 has a base 91 and a top 92 when the laminated body 814 transported in the transport direction F passes through the nip between the embossed roll 805a and the anvil roll 805b. ) 90 shows the process of being squeezed to form a recess. In the method for producing an absorber of the present invention, the embossed spin 90 provided on the outer peripheral surface of the embossed roll 805a rotating in the same direction as the transport direction F of the laminated body 814 is the embossed spin 90 according to the rotation of the 805a and the anvil roll 805b. When the top portion 92 comes into contact with the surface of the laminated body 814, the angle θ formed by the side surface SS of the top portion 92 and the surface of the laminated body 814 on the downstream side in the transport direction of the laminated body is in the range of 0 to 60 degrees. The angle θ is preferably 0 to 30 degrees. The larger the angle θ, the less effective it is to prevent the core wrap from being damaged because the pressing pressure on the laminate is less likely to be dispersed when the top of the embossed spin comes into contact with the laminate.

The absorbent articles of the present disclosure are not particularly limited, and for example, absorbent articles that mainly absorb urine, such as disposable diapers, urine absorbing pads, urination sheets for animals, and the like, absorb menstrual blood and the like. Sexual articles such as sanitary napkins, panty liners and the like can be mentioned.

Hereinafter, the present invention will be described in more detail based on Examples, but the scope of the present invention is not limited to Examples.

(1) Preparation of absorber [Examples 1 to 10]
From the absorbent material containing the basis weight pulp (NB416 manufactured by Wayerhauser) and SAP particles (SA60S manufactured by Sumitomo Seika Co., Ltd.) shown in Table 1 below by the manufacturing apparatus shown in FIG. 8, the first length 115 mm × width 330 mm. 1 laminate (corresponding to the precursor of the absorption core) is formed, and the first laminate is coated with an SMS non-woven fabric (basis weight 10 g / m ² ) as a core wrap to form a second laminate, and then the second laminate is formed. The second laminate is squeezed by a pair of rolls, that is, a squeezing device equipped with embossed rolls and anvil rolls in which a plurality of embossed spins are arranged on the outer peripheral surface at a nip interval of 0.5 to 0.7 mm and a nip pressure of 0.15 MPa. Then, it was cut into a size of 130 mm in length × 360 mm in width to prepare an absorber. The speed at which the second laminate passed through the nip was about 5 m / s. As shown in FIG. 12, the embossed rolls of the embossed rolls used in Examples 1 to 10 had an octagonal columnar base. The top of the embossed spin of the embossed roll used in Examples 1 to 10 had a shape in which the four corners of the top surface were chamfered with R0.25 and the four corners of the bottom surface were chamfered with C0.9. In the embossed rolls used in Examples 1 to 3, the embossed spins were arranged in a staggered pattern, as shown in FIG. 10C. In the embossed rolls used in Examples 4 to 10, the embossed spins were arranged in a parallel pattern in the MD direction and the CD direction, as shown in FIG. 10B. Table 1 below shows the dimensions of the top of the embossed spins of the embossed rolls used in Examples 1 to 10 (that is, the CD-direction length LT1 of the top surface, the MD-direction length LT2 of the top surface, and the CD-direction length LB1 of the bottom surface. , MD direction length LB2) of the bottom surface and the shortest distances D1 and D2 between adjacent embossed spins in the CD direction and the MD direction. In the CD direction and the MD direction, the angles α ₁ and β ₁ formed by the side surface and the bottom surface of the top are both 30 degrees, and the angles α ₂ and β ₂ formed by the side surface and the bottom surface of the base are both 90 degrees. It was. Therefore, the area of the bottom surface of the base of the embossed spin is equal to the area of the bottom surface of the top. If the angle alpha _2, beta ₂ are both 90 degrees, the area ratio S _r of the bottom surface of the base of the embossing pins, and the CD direction and the MD direction of the bottom surface of the top length and respectively LB1 and LB2, between the embossing pins When the shortest intervals in the CD direction and the MD direction are expressed as D1 and D2, respectively, in the staggered arrangement, the equation (1):
S _r = (LB1 x LB2) / {2 x (LB1 + D1) x (LB2 + D2)}
In a parallel array, equation (2):
S _r = (LB1 x LB2) / {(LB1 + D1) x (LB2 + D2)}
Can be obtained according to.

[Comparative Examples 1 to 3]
Except for the fact that a flat press was used instead of the embossed roll, the absorbers of Comparative Examples 1 to 3 were prepared in the same manner as the absorbers of Examples 1 to 3, respectively. The flat press was set to have a clearance of 0 mm, a press pressure of 5.8 MPa, and a press time of 5 seconds.
[Comparative Examples 4 to 6]
The absorbers of Comparative Examples 4 to 6 have a top surface dimension of 1.40 mm × 0.60 mm, a bottom surface dimension of 2.30 mm × 1.50 mm, and a height of 0.45 mm, and each of the four side surfaces has a bottom surface. Example 1 except that a plurality of embossed rolls having a quadrangular pyramid shape forming an angle of 45 degrees are provided on the outer peripheral surface at intervals of 2.70 mm in the CD direction and 4.5 mm in the MD direction. It was prepared in the same manner as in ~ 3. The shape and dimensions of the embossed spin correspond to the protrusions formed on the outer peripheral surface of the upper roll of the embossing apparatus described in Patent Document 2.

(2) Evaluation method of 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 super absorbent polymer in the absorber was investigated by observing the internal structure of the absorber non-destructively using an X-ray CT apparatus. The X-ray CT apparatus used was FLEX-M863 manufactured by Beamsense Co., Ltd. The software used for X-ray CT imaging was BSFM manufactured by Beamsense Co., Ltd., the software used for synthesizing captured images was Beamsense CT, and the software used for analyzing captured images was Volume Exector. The tube voltage was 40 kV, the tube current was 100 μA, and the imaging time per shot was 1 second. The absorber sample is placed and fixed on a table that can rotate 360 degrees around the rotation axis perpendicular to the axis connecting the X-ray source and the center of the detection surface of the two-dimensional detector, and the absorber sample is rotated 360 degrees. However, a total of 720 images were obtained by taking a picture once every 0.5 degrees. 720 images were combined. When the absorber sample is viewed in a plan view from the X-ray CT composite image, 10 pairs of two adjacent embossed recesses are randomly sampled in the length direction of the absorber sample, and the tsubo of the superabsorbent polymer in these embossed recesses. The average value (b1) of the amount was calculated. Further, the average value (b2) of the basis weight of the superabsorbent polymer in the convex portion located between the two adjacent embossed recesses of 10 pairs sampled at random was determined. The percentage of b1 to b2, that is, the value of 100 × b1 / b2 was determined. The values of 100 × b1 / b2 for Examples 1 to 10 are shown in Table 2. In Comparative Examples 1 to 6, no bias was observed in the distribution of the superabsorbent polymer in the X-ray CT observation.

[Rigidity test]
A sample having a size of 20 mm × 50 mm was punched from the absorber, and the mass and thickness of the sample were measured. The mass was measured with an electronic balance, and the thickness was measured with a PEACOCK dial thickness gauge JB (meter diameter: 50 mm, pressure: 294 Pa) manufactured by Ozaki Seisakusho Co., Ltd. Attach the digital force gauge (FGP-2 manufactured by Nippon Densan Symposium Co., Ltd.) to the force gauge stand (FGS-50S manufactured by Nippon Densan Symposium Co., Ltd.), and bend it at three points to the stylus mounting part of the digital force gauge. A pressing portion (indenter) of a jig (GA-10N manufactured by Imada Co., Ltd.) was attached, and the pedestal portion of the three-point bending jig was placed on the measurement table of the force gauge stand. The indenter radius was 2.5 mm and the fulcrum radius was 2.5 mm. The opening width was set to 15 mm, and the sample was placed on the pedestal portion of the bending jig so that the tip of the pressing portion (indenter) of the bending jig was in contact with the central portion of the sample. A load was applied to the sample at a crosshead speed of 1.5 mm / s, and the maximum load when the sample was bent was recorded as a rigidity value. Tables 3 to 5 show the evaluation results of the rigidity together with the density of the absorber obtained from the above size, mass and thickness of the absorber.

FIG. 14 shows a graph of density (g / cm ³ ) vs. rigidity (N) of the absorbers of Examples 1 to 3 embossed using embossed rolls according to the present invention. A graph of density (g / cm ³ ) vs. rigidity (N) for Comparative Examples 1 to 3 embossed using a flat press is shown in FIG. A graph of density (g / cm ³ ) vs. rigidity (N) for the absorbers of Comparative Examples 4 to 6 embossed using embossed rolls is shown in FIG.

From FIGS. 14 to 16 and Table 8, for Examples 1 to 3, the region where the absorber density is relatively low as compared with Comparative Examples 1 to 3 and 4 to 6 (that is, the absorber density is 0.2 g / cm). Standard for regions with high rigidity (regions of ³ or more and less than 0.3 g / cm ³ ) and relatively high absorber densities (ie, regions of absorber densities of 0.4 g / cm ³ or more and less than 0.5 g / cm ³ ) The deviation value was small (ie, the variation was small). It can be seen that the samples of Comparative Examples 1 to 3 and 4 to 6 had so-called hard spots having extremely high rigidity.

[Tactile evaluation]
The tactile sensations of the samples of Examples 1 to 3 and Comparative Examples 1 to 6 were sensory evaluated by 10 skilled panelists, and the evaluation results were graded on a scale of 1 to 3.
Grade 1: No hard spots are observed, which is preferable for use in baby diapers.
Grade 2: Slightly hard spots were found, but acceptable for use in baby diapers.
Grade 3: Contains very hard parts and is not preferred for use in baby diapers.
Samples rated as Grade 1 are given a rating of "0", samples rated as Grade 2 are rated as "1", and samples rated as Grade 3 are rated as "2". Scores were given and the total evaluation points were calculated. The smaller the total of the evaluation points, the better the tactile sensation, which is more preferable for use in baby diapers.

From Table 9, it can be seen that Examples 1 to 3 of the present invention have a preferable tactile sensation for use in baby diapers as compared with Comparative Examples 1 to 3.

1 Disposable diaper 2 Liquid permeable front sheet 3 Liquid permeable back sheet 5, 5 Side sheet 6, 6 Elastic member 7 Tape embosser 4,100,100'absorbent 110 Absorbent core 114,8S Superabsorbent polymer particles 116,8F Hydrophilic fiber 120 Core wrap 130 Outer edge 140, 140'Recess 141, 141' Recessed open end 142 Recess bottom 142a, 142a' Bottom bottom 142b, 142b' Bottom inclined surface 145, 145'Convex 145a , 145a'Area adjacent to the concave part 146 Convex part 150R, 150L Deformation induction part 800,800' Absorbent manufacturing equipment 801 Conveyor pipe 802 Suction drum 803 Concave mold member 804 Unwinding roll 805,805' Squeezing equipment 805a , 805a'embossed roll 805b, 805b' anvil roll 811 first laminated body 812 core wrap continuum 813 second laminated body 814,816 laminated body 815 third laminated body 817 fourth laminated body 90 embossed spin 91 base 92 Top d, d'Recess depth h Embossed spin height α ₁ , β ₁ , α ₂ , β ₂ Tilt angle

Claims (8)

It contains an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer, and a core wrap covering the absorbent core, and includes a length direction, a width direction, a thickness direction, and a skin surface side surface and a non-skin surface. An absorber for absorbent articles with a side surface,
The absorber is at least one region having a super absorbent polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more, and is one of a skin surface side surface and a non-skin surface side surface. Or both have at least one region having a plurality of interspersed recesses and protrusions located between the plurality of recesses, and the length of the absorber when the absorber is viewed in a plan view. With respect to the portion of the convex portion located between any two adjacent recesses in the direction and the two adjacent recesses, the average value of the basis weight of the superabsorbent polymer in the two adjacent recesses is said. Less than the basis weight of the superabsorbent polymer in the convex part,
An absorber characterized by. The absorber according to claim 1, wherein the plurality of interspersed recesses are portions of the absorber that are consolidated in the thickness direction. The absorber according to claim 1 or 2 , wherein the average value of the basis weight of the superabsorbent polymer in the two recesses is 15% or more less than the basis weight of the superabsorbent polymer in the convex portion. Claimed that the area ratio of the plurality of recesses in the at least one region of the absorber in plan view is 25 to 65% independently on one or both of the skin surface side surface and the non-skin surface side surface. Item 2. The absorber according to any one of Items 1 to 3 . Claims 1 to 4 wherein the plurality of recesses each have a rectangular shape having an area of ² to 50 mm ^{2 in} a plan view, and the distance between adjacent recesses in the length direction of the absorber is 0.5 to 10 mm. The absorber according to any one of the above. The invention according to any one of claims 1 to 5 , wherein the absorber has a pair of deformation guiding portions extending in a predetermined direction, and the plurality of recesses are present between the pair of deformation guiding portions. Absorber. An absorbent article containing the absorber according to any one of claims 1 to 6 . The method for producing an absorber for an absorbent article according to claim 1.
(A) A step of covering the absorption core with a core wrap to form a laminate having first and second surfaces corresponding to the skin surface side surface and the non-skin surface side surface of the absorber, respectively, and (b). The step of forming the absorber according to claim 1 by pressing one or both of the first surface and the second surface of the laminate with an embossing roll that rotates in the transport direction of the laminate while conveying the laminate. ,
Including
The embossed roll has at least one region provided with a plurality of scattered protrusions on its outer peripheral surface.
The plurality of interspersed convex portions on the outer peripheral surface of the embossed roll each include a base portion and a hemispherical or n-side pyramidal trapezoidal shape (n is an integer of 4 or more).
In the step (b), the angle between the side surface of the top and the laminate on the downstream side in the transport direction when the top comes into contact with the surface of the laminate according to the rotation of the emboss roll is 0 to 60 degrees. Is within the range of
Manufacturing method of absorber.

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