WO2018100704A1 - Absorber, method for manufacturing same, and absorbent article - Google Patents

Abstract

Provided is an absorber (100) comprising: an absorbent core (110) that includes hydrophilic fibers and particulate superabsorbent polymer; and a core wrap (120) that covers the absorbent core. The absorber (100) has: a length direction, a width direction, and a thickness direction, and a skin side surface and a non-skin side surface; and at least one region which has a superabsorbent polymer content of 40 to 85 mass% and an average density of 0.15 g/cm³ or more, and which has, on one or both of the skin side surface and the non-skin side surface, a plurality of interspersed recesses and projections positioned between the plurality of recesses. For two arbitrary adjacent recesses in the length direction of the absorber when the absorber is viewed in plan view and the portion of the projection positioned between the two arbitrary adjacent recesses, the average value of basis weight of the superabsorbent polymer of the two arbitrary adjacent recesses is less than the basis weight of the superabsorbent polymer of the portion of the projection. Also provided are an absorbent article comprising the absorber and a method for manufacturing the absorber.

Description

Absorber, method for producing the same, and absorbent article

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

Absorbent articles such as sanitary napkins and disposable diapers include absorbent bodies for absorbing liquids such as urine and menstrual blood. Such absorbent bodies generally include hydrophilic fibers such as pulp and superabsorbent polymers. It is manufactured by forming an absorbent core by depositing particles of (SuperabsorbentＳPolymer: SAP) and coating the absorbent core with a core wrap. About the absorber used for an absorbent article, in order to prevent the uncomfortable feeling at the time of wearing resulting from the thickness of an absorber, and twisting at the time of wearing, etc., an absorber precursor is embossed with an embossing roll. Thus, Patent Document 1 proposes that the thickness of the absorber is reduced to give rigidity. Regarding the technology for imparting rigidity to the absorbent body by embossing, the 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 embossing roll Patent Document 2 proposes embossing a covering (absorber precursor) using an embossing roll parallel to (CD direction). In Patent Document 2, when each convex portion hits the absorber precursor when the embossing roll is rotated, one side of the top surface of each convex portion first hits the absorber precursor not by point contact but by line contact. It is described that the pressing pressure by each convex part can be disperse | distributed to the width direction (CD direction) of a roll, and the failure | damage of the coating sheet (core wrap) which makes the outer peripheral part of a coating body can be prevented. When the covering sheet is damaged, SAP particles leak from the damaged portion, so that the liquid absorption holding performance of the absorber is deteriorated.

By the way, in recent years, it has been required to make the absorbent body for absorbent articles thinner without impairing the absorbability. However, in order to reduce the thickness without impairing the absorption capacity of the absorber, when the proportion of SAP particles in the constituent components of the absorbent core constituting the absorber is increased, the SAP particles in the portion compressed by embossing Are likely to coalesce or agglomerate to form a harder (feeling of touch) portion (generally called “hard spot”) than the surrounding area. The hard spot can give the wearer of the absorbent article a feeling of strangeness. Further, as described in Patent Document 3, the higher the production line of the absorbent core and / or the thinner the thickness of the absorbent core, the greater the non-uniformity of the material constituting the absorbent core. As a result, hard spots are likely to occur in areas where the basis weight or proportion of SAP particles is higher than their surroundings during the manufacture of the absorbent core. Further, when the thickness of the absorber is reduced, the height of the convex portion on the outer peripheral surface of the embossing roll is increased to increase the emboss depth, so that the convex portion is likely to break through the covering sheet (core wrap).

JP 2003-33397 A JP2015-39385A JP 2012-510849 A

The present invention has been made in view of the above problems, and although it has a region containing a high water-absorbing polymer at a high content, the occurrence of hard spots is suppressed, and it is difficult to lose its shape and is good. It aims at providing the absorber which shows a feeling of touch and a feeling of wear.

As a result of studying to solve the above-mentioned problems, the inventors of the present invention include an absorbent core containing hydrophilic fibers and a particulate superabsorbent polymer, and a core wrap covering the absorbent core, in the length direction, In an absorbent article for absorbent articles having a width direction and a thickness direction, and a skin surface side surface and a non-skin surface side surface, the absorbent body has a high water-absorbing polymer content of 40 to 85% by mass and 0. It is at least 1 area | region which has an average density of 15 g / cm < ³ > or more, Comprising: It is located between one or both of the skin surface side surface and the non-skin surface side surface, and a plurality of recessed portions, and between the plurality of recessed portions Between the two adjacent concave portions and the two adjacent concave portions in the length direction of the absorber when the absorber is viewed in plan. About the part of the convex part located, the arbitrary When the average basis weight of the superabsorbent polymer in two adjacent recesses is less than the basis weight of the superabsorbent polymer in the convex portion, at least one region containing the superabsorbent polymer at a high content The present inventors have found that the occurrence of hard spots is suppressed despite having the above, has an appropriate rigidity, is not easily deformed, and provides a good feel and feel.

Further, the present inventors have a first surface and a second surface corresponding to the skin surface side surface and the non-skin surface side surface of the absorbent body, respectively, by pressing the laminated body of the absorbent core and the core wrap with an embossing roll. When one or both of the laminates are formed with the plurality of recessed portions, the plurality of protruding portions provided on the outer peripheral surface of the embossing roll are respectively formed into a base and a hemispherical shape or an n-pyramidal frustum (n is 4 The top of the convex portion on the downstream side in the transport direction of the laminate when the top of the convex portion comes into contact with the surface of the laminate in accordance with the rotation of the embossing roll in the pressing step. It was found that breakage of the core wrap can be remarkably reduced when the angle between and is in the range of 0 to 60 degrees, particularly preferably in the range of 0 to 30 degrees. Since the breakage of the core wrap in the pressing process can be suppressed, the rotational speed of the embossing roll can be increased, thereby increasing the production speed of the absorbent body. Further, when the absorber is thinned, the emboss depth of the laminate can be increased in order to impart rigidity to the absorber without excessively increasing the density of the absorber. Even when the absorption core subjected to the pressing process includes a hard spot, the SAP particles are rearranged by deeply pushing the plurality of protruding portions of the embossing roll in the thickness direction of the absorption core or the aggregation of the SAP particles is solved. Since it can be crushed, the hard spot which existed in the absorption core before the pressing process can be eliminated or reduced. Furthermore, since the SAP particles can be rearranged by deeply pushing the plurality of protruding portions of the embossing roll in the thickness direction of the absorbent core, generation of hard spots due to the pressing process can be reduced. Therefore, in spite of having a region containing a high water-absorbing polymer at a high content rate, the occurrence of hard spots is suppressed, it has moderate rigidity, is not easily deformed, and provides an excellent feeling of touch and wearing. The body can be manufactured at high speed. The present invention has been completed based on the above findings.

That is, the present invention, in one embodiment,
An absorbent core containing hydrophilic fibers and particulate superabsorbent polymer; and a core wrap covering the absorbent core; a length direction, a width direction and a thickness direction; a skin surface side surface and a non-skin surface An absorbent body for absorbent articles having a side surface,
The absorbent body is at least one region having a high water-absorbing polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more, wherein the skin-side surface and the non-skin-side surface It has at least one area | region which has the some recessed part scattered in one or both, and the convex part located between these recessed parts, and the length of the said absorber when the said absorber is planarly viewed The average value of the basis weight of the superabsorbent polymer in the two adjacent concave portions is about the convex portion located between the two adjacent concave portions in the vertical direction and the two adjacent concave portions. Less than the basis weight of the superabsorbent polymer in the convex part,
It is an absorber characterized by.

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

In a further embodiment, the present invention provides a method for producing the above-described absorbent,
(A) covering the absorbent core with a core wrap to form a laminate having a first surface and a second surface respectively corresponding to the skin surface side surface and the non-skin surface side surface of the absorber; and (b) Squeezing one or both of the first surface and the second surface of the laminated body with an embossing roll rotating in the conveying direction of the laminated body while conveying the laminated body to form the absorbent body;
Including
The embossing roll has at least one region provided with a plurality of interspersed convex portions on its outer peripheral surface,
Each of the plurality of protrusions on the outer peripheral surface of the embossing roll includes a base and a hemispherical or n-pyramidal frustum shape (n is an integer of 4 or more),
In the step (b), when the top portion contacts the surface of the laminated body according to the rotation of the embossing roll, the angle formed between the side surface of the top portion on the downstream side in the transport direction and the laminated body is 0 to 60 degrees. Is within the range of
It is a manufacturing method of an absorber.

The absorbent body for an absorbent article of the present invention has a region containing a high water-absorbing polymer at a high content rate, and the occurrence of hard spots is suppressed. A feeling and a feeling of wearing are shown. The method for producing an absorbent body for an absorbent article of the present invention reduces the occurrence of core wrap breakage and hard spots despite having a region containing a high water-absorbing polymer content, and is not easily deformed. This provides an absorbent body that exhibits a good feel and a feeling of wear.

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 absorber shown in FIG. FIG. 3A is a schematic cross-sectional view taken along the line III-III of the region B of the absorber shown in FIG. FIG. 3B is a schematic cross-sectional view of an essential part of an absorbent body 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 line VV of the absorber shown in FIG. FIG. 6 is a schematic plan view showing a developed state of the disposable diaper including the absorbent body of the present invention. FIG. 7 is a perspective view schematically showing the disposable diaper shown in FIG. 6 when it is transformed into a predetermined shape. FIG. 8 is a schematic diagram illustrating an example of a manufacturing apparatus for manufacturing an absorbent body according to an embodiment of the present invention. FIG. 9 is a schematic diagram illustrating an example of a manufacturing apparatus for manufacturing an absorbent body according to another embodiment of the present invention. FIG. 10A is a three-view drawing of an example of embossed spin provided on the outer peripheral surface of the embossing 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 embossing roll is viewed in plan. FIG. 10C is a plan view showing another example of the arrangement of emboss 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 embossed spin (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 embossed spin (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 embossed spin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan. FIG. 11D is a plan view showing yet another example of the shape of the top surface of the embossed spin (convex portion) when the outer peripheral surface of the embossing roll is viewed in plan. FIG. 12 is a three-view diagram of another example of embossing pins provided on the outer peripheral surface of the embossing roll. FIG. 13 is a schematic enlarged view of the nip between the embossing roll 805a and the anvil roll 805b of the pressing 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 density (g / cm ³ ) vs. rigidity (N) of the absorbers of Comparative Examples 1 to 3. FIG. 16 is a graph of the density (g / cm ³ ) versus rigidity (N) of the absorbent bodies of Comparative Examples 4 to 6.

Some of the embodiments of the invention related to the present invention are shown below.
[Aspect 1]
An absorbent core containing hydrophilic fibers and particulate superabsorbent polymer; and a core wrap covering the absorbent core; a length direction, a width direction and a thickness direction; a skin surface side surface and a non-skin surface An absorbent body for absorbent articles having a side surface,
The absorber is at least one region having a high water-absorbing 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 having at least one region having a plurality of recessed portions interspersed with each other and a protruding portion located between the plurality of recessed portions, and the length of the absorber when the absorber is viewed in plan view. The average basis weight of the superabsorbent polymer in the two adjacent concave portions is the two adjacent concave portions in the direction and the convex portion located between the two adjacent concave portions. Less than the basis weight of the superabsorbent polymer in the convex part,
Absorber characterized by.
In the absorber according to the first aspect, in at least one region having the predetermined high water-absorbing polymer content and the average density, any two adjacent two in the length direction of the absorber when the absorber is viewed in plan view. About the convex part located between two concave parts and the two adjacent concave parts, the average value of the basis weight of the superabsorbent polymer in the two adjacent concave parts is the high water absorption in the convex part. Since the basis weight of the conductive polymer is less, the generation of hard spots is suppressed. Furthermore, as for the said absorber, the several recessed part is formed in one or both of the skin surface side surface and the non-skin surface side surface in at least 1 area | region which has said predetermined high water absorption polymer content rate and average density. Since the absorber is provided with rigidity and there are convex portions between the plurality of recesses, when the absorbent article including the absorber is worn by the wearer, it is difficult to lose shape, It is flexible and can provide a good touch feeling and a good wearing feeling.

[Aspect 2]
The absorbent body according to aspect 1, wherein the average value of the basis weight of the superabsorbent polymer in the two concave portions is 15% or more less than the basis weight of the superabsorbent polymer in the convex portion.
The absorber which concerns on aspect 2 is a thing by which generation | occurrence | production of the hard spot was suppressed more reliably. Therefore, when the absorbent article containing the said absorber is worn by the wearer, it is difficult to lose its shape, and it is possible to more reliably provide a good touch feeling and wearing feeling.

[Aspect 3]
The area ratio in plan view of the plurality of recesses in the at least one region of the absorber is independently 25 to 65% on one or both of the skin surface side surface and the non-skin surface side surface, The absorbent body 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. When the area ratio of the recess exceeds 65%, the rigidity of the absorber may be too high.

[Aspect 4]
The above aspects 1 to 3, wherein each of the plurality of recesses has a rectangular shape having an area of 2 to 50 mm ^{2 in} plan view, and an interval between adjacent recesses in the length direction of the absorber is 0.5 to 10 mm. The absorber as described in any one of these.
When the planar view area of each recess is less than 2 mm ² , since the contact area is small, the effect of suppressing the occurrence of a hard spot by rearranging the SAP is reduced, and the risk of damaging the core wrap increases. When the planar view area of each recessed part exceeds 50 mm < ² >, there exists a possibility that the rigidity of an absorber may become high and a favorable touch may be impaired. If the interval between the adjacent concave portions in the length direction of the absorber is less than 0.5 mm, the SAP movement is limited, and thus the effect of suppressing the generation of hard spots is not sufficient. When the interval between the adjacent recesses in the length direction of the absorber exceeds 10 mm, there is a region where the SAP cannot be rearranged, and thus the effect of suppressing generation of hard spots is reduced.

[Aspect 5]
5. The aspect according to any one of the above aspects 1 to 4, wherein the absorbent body has a pair of deformation guide portions extending in a predetermined direction, and the plurality of recesses exist between the pair of deformation guide portions. Absorber.
The absorptive component containing the absorber which concerns on aspect 5 fits a wearer's wear site | part, and can prevent leakage of liquids, such as urine and menstrual blood.

[Aspect 6]
An absorbent article comprising the absorbent body according to any one of the above aspects 1 to 5.
When the absorbent article according to Aspect 6 is worn by the wearer, the absorbent article is not easily deformed, and provides a good touch feeling and wearing feeling.

[Aspect 7]
It is a manufacturing method of the absorber for absorptive articles according to claim 1,
(A) covering the absorbent core with a core wrap to form a laminate having a first surface and a second surface respectively corresponding to the skin surface side surface and the non-skin surface side surface of the absorber; and (b) Squeezing one or both of the first surface and the second surface of the laminated body with an embossing roll rotating in the conveying direction of the laminated body while conveying the laminated body to form the absorbent body;
Including
The embossing roll has at least one region provided with a plurality of interspersed convex portions on its outer peripheral surface,
The plurality of interspersed convex portions on the outer peripheral surface of the embossing roll each include a base and a hemispherical or n-pyramidal frustum shape (n is an integer of 4 or more),
In the step (b), the angle formed between the side surface of the top portion and the laminate on the upstream side in the rotation direction of the emboss roll when the top portion contacts the surface of the laminate according to the rotation of the emboss roll is 0 to Within the range of 60 degrees,
Manufacturing method of absorber.
According to the manufacturing method of the absorber which concerns on the said aspect 7, the some convex part provided in the outer peripheral surface of the embossing roll used in a process (b) is a hemispherical shape or an n truncated pyramid shape (n is 4 or more). It has an integer) apex (tip) and is not thin and sharp, so it is difficult to break the core wrap during the pressing process. Further, since the plurality of convex portions of the embossing roll have a structure in which the top portion is bonded to the outer peripheral surface of the embossing roll via the base, the laminate is squeezed more deeply with a larger contact area ratio in the thickness direction. be able to. After the top of the convex part of the embossing roll comes into contact with the surface of the laminate, the top of the convex part squeezes the laminated body in the thickness direction while pushing away the particles of the superabsorbent polymer. At the same time, part of the superabsorbent polymer particles moves around the recess. Therefore, in the part (concave part) squeezed by the convex part of the embossing roll according to the present invention, the basis weight of the superabsorbent polymer is reduced as compared with before the squeezing by the embossing roll, and adjacent to the compressed part (concave part). In the portion (convex portion), the basis weight of the superabsorbent polymer is increased as compared with that before pressing with the embossing roll. In other words, the superabsorbent polymer particles are rearranged by pressing with the embossing roll, and the generation of hard spots is suppressed. Furthermore, if there are hard spots derived from the non-uniform distribution of the superabsorbent polymer particles in the absorbent core before pressing with the embossing roll, the hard spots are eliminated or reduced by the step (b). be able to.

[Definition of terms]
Definitions of terms used in this specification will be described.
In this specification, unless otherwise specified, “view an object (for example, an absorbent article, an absorbent body, etc.) placed on a horizontal surface in an unfolded state from the upper side in the vertical direction in the thickness direction of the object. Is simply referred to as “plan view”.
The “width direction WD” refers to the “direction in which the length of the vertically long object in the plan view is short (short direction)”, and the “length direction LD” refers to the “length of the vertically long object in the plan view”. “Long direction (longitudinal direction)”, “thickness direction TD” means “perpendicular direction (that is, thickness direction of the object) with respect to the unfolded state on the horizontal plane”, and these widths The direction WD, the length direction LD, and the thickness direction TD are 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 It 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 elongated object, it refers to the relatively proximal to as "inner side in the longitudinal direction" to the central longitudinal axis C _W extending in the width direction W, elongated object In the longitudinal direction L of the object, the distal side relative to the longitudinal central axis _{CW is referred} to as “the outward side in the longitudinal direction”.
In the thickness direction TD of the absorbent article, “relatively proximal to the skin surface of the wearer when the absorbent article is worn” is referred to as “skin side” and “the wearer wears the absorbent article. The “distal surface relative to the skin surface” is referred to as the “non-skin surface side”.
With respect to the absorber, the “concave portion” refers to a portion of the absorber that is consolidated in the thickness direction.
With respect to any two adjacent recesses in the length direction of the absorber, the “average basis weight of the superabsorbent polymer” means a superabsorbent polymer content of 40 to 85 mass% of the absorber and 0.15 g. It means the average value of the basis weight of the superabsorbent polymer for 10 pairs of two concave portions adjacent to each other in the length direction, which are randomly sampled in a region having an average density of / cm ³ or more.
With respect to the convex portion located between any two adjacent concave portions in the length direction of the absorbent body, the “basis weight of the superabsorbent polymer” is 10 pairs of lengths randomly sampled as described above. The average value of the basic weight of the part of the convex part located between two recessed parts adjacent to a direction is meant.
With respect to the absorber, “the portion of the convex portion positioned between any two adjacent concave portions in the length direction of the absorber” refers to the opening 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 end portions in the width direction of these contour lines.
With respect to the absorber, the “region having a plurality of scattered recesses” means a region surrounded by the shortest envelope connecting the edges of the recesses located on the outermost side of the plurality of scattered recesses.

DESCRIPTION OF EMBODIMENTS Preferred embodiments 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 to the same scale and shape as actual components in order to facilitate understanding of the present invention. The same reference number represents the same element.
[Absorber]
With reference to FIG. 1, the absorber which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a schematic plan view showing an embodiment of an absorbent body taking an absorbent body 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 LD and WD, and includes an absorption core 110 and an absorption core 110. A core wrap 120 covering the outer periphery of the core. FIG. 1 shows the skin side surface when the absorbent body 100 is worn by a wearer in a state where the absorbent body 100 is incorporated in a disposable diaper. The abdomen side, the crotch abdomen side, the crotch dorsal side and the back side of the wearer are shown. An abdominal region A1, an inseam abdomen region A2, an inseam dorsal region A3, and a dorsal region A4 of the absorbent body 100 in contact with 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 concave portions 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 edge of the absorbent core 110. The plurality of concave portions 140 scattered in the regions A1c, A2c, A3c, and A4c are portions that are consolidated by compressing corresponding portions of the absorbent core and the core wrap in the thickness direction of the absorbent body 100, and are a plurality of scattered portions. This 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. Absorber 100 is recessed in the area A1c to A4c in a concave shape with respect to the surface on the skin surface side of outer edge portion 130, and the thickness of the absorber in areas A1c to A4c is smaller than the thickness of 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 thicknesses measured by a PEACOCK dial thickness gauge JB (measurement element diameter: 50 mm, pressure: 294 Pa) manufactured by Ozaki Mfg. Co., Ltd. It 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 on the skin side surface of the absorbent body 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 is Independently, as long as it 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 a convex portion located between the plurality of concave portions, the absorbent body of the present invention is a figure. 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 absorbent body but on the non-skin surface side surface, or on both the skin surface side surface and the non-skin surface side surface. .

The absorbent core 110 includes at least hydrophilic fibers and particulate superabsorbent polymer. Examples of the hydrophilic fiber include cellulosic water-absorbing fibers such as pulp. Furthermore, a hydrophilic synthetic fiber may be included. Examples of the superabsorbent polymer include superabsorbent polymers that are generally used in absorbent bodies for absorbent articles such as starch-based, cellulose-based, and synthetic polymer-based polymers. In the consolidated part of the absorbent body, the hydrophilic fiber density of the absorbent core is higher than the hydrophilic fiber density of the absorbent core in the unconsolidated part.

The core wrap 120 is not particularly limited as long as the core wrap 120 has a function of retaining the liquid permeable material and the constituent material of the absorbent core in the absorbent body. ) Nonwoven fabric and the like. Further, in both cases where the core wrap is made of tissue paper and the core wrap is made of a nonwoven fabric, the basis weight is preferably 10 to 30 g / m ² .

When the superabsorbent polymer content in the at least one region provided with a plurality of interspersed concave portions is less than 40% by mass, the absorbent body is kept at a moderately high level while maintaining the absorbent performance at a moderately high level. However, when the content of the superabsorbent polymer exceeds 85% by mass, the wearer may feel uncomfortable due to the crisp feel of the SAP particles. Moreover, when the content rate of a highly water-absorbing polymer exceeds 85 mass%, a gel blocking phenomenon generate | occur | produces and liquid absorption performance may fall. When the average density in the at least one region provided with a plurality of interspersed concave portions is less than 0.15 g / cm ³ , an appropriate rigidity is realized within the range of the high water-absorbing polymer content rate. 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 absorbent body of the present invention, the area ratio in plan view of the plurality of recesses is preferably Is 25 to 65%. When the area ratio of the recess is less than 25%, the effect of increasing the rigidity is not sufficient. When the area ratio of the recess exceeds 65%, the rigidity of the absorber may be too high. For any region of the absorber, the superabsorbent polymer content is determined by cutting out 5 samples of a predetermined length and width from the absorbent core (for example, 20 mm x 50 mm), and measuring each sample mass and then including it in 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 superabsorbent polymer mass to each sample mass is calculated. For an arbitrary area of the absorber, the average density is obtained 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 measuring the measured values as described above. It can obtain | require by the average value of what remove | divided by the volume of the sample obtained by the thickness obtained by the measuring method, and the area of a sample.

As described below with reference to FIG. 2, when the skin surface side surface having the plurality of recessed portions 140 interspersed with the absorbent body 100 is viewed in plan, the recessed portion 140 is L1 in the width direction WD of the absorbent body. Each of the recesses has a bottom 142 having a dimension L3 in the width direction WD of the absorber and a dimension L4 in the length direction LD. L1 is preferably 2 to 25 m, more preferably 2 to 8 mm, and further preferably 3 to 5 mm. L2 is preferably 1 to 25 mm, more preferably 1.5 to 6 mm, and still more preferably 2 to 4 mm. The area S (= L1 × L2) of the open end 141 of the recess is preferably 2 to 50 mm ² , more preferably 3 to 30 mm ² , and even more preferably 5 to 20 mm ² . The shortest distance L5 between the open ends of adjacent recesses in the width direction WD of the absorber is preferably 0.5 to 10 mm, more preferably 1 to 6 mm, and further preferably 2 to 5 mm. The shortest distance L6 between the open ends of adjacent recesses in the length direction LD of the absorber is preferably 0.5 to 10 mm, more preferably 1 to 6 mm, and further preferably 2 to 5 mm. Here, L1 to L4 and S are 10 recesses randomly sampled in a region having a high water absorption polymer content of 40 to 85% by mass of the absorber and an average density of 0.15 g / cm ³ or more, respectively. Means the average value of L1 to L4 and S. L5 and L6 are respectively between the opening ends of the recesses adjacent to each other in 10 pairs of the width direction WD and the length direction LD sampled at random in the region having the predetermined superabsorbent polymer content and average density of the absorber. Means the shortest interval. The “convex portion” located between two adjacent concave portions includes contour lines 141a and 141b facing each other at the opening ends of two concave portions adjacent to each other in the length direction of the absorber, and the width direction of these contour lines. 2 is a region surrounded by two straight lines connecting the corresponding ends of each other, and is indicated by reference numeral 146 in FIG. In FIG. 2, the contour lines 141a and 141b of the opening ends of two adjacent recesses facing each other correspond to the sides of the opening ends of the adjacent recesses facing each other. When the absorber is viewed in plan, 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, pentagon, hexagon, heptagon, or octagon. Furthermore, as will be described below with reference to FIG. 3A, the recess 140 is formed in a thickness direction of the absorber with respect to a protrusion located between the plurality of recesses, that is, a surface area between the open ends of the plurality of recesses. It is recessed at a depth d in TD. 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” refers to 10 recesses randomly sampled in a region having a superabsorbent polymer content of 40 to 85% by mass and an average density of 0.15 g / cm ³ or more. Means the maximum depth. The average values of L1 to L6 and S and the depth d of the recesses are measured using a laser displacement meter (for example, a high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Corporation). It can be measured by measuring in a non-contact manner.

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 A difference in rigidity occurs in the direction, and the absorber is easily bent along the bending guide lines BLa, BLb, and BLc where the width of the absorbent 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 can take any shape such as a polygonal shape or an arc shape as long as interference between the end portions of the absorber can be prevented. The notch part does not need to be provided in the absorption core. A notch part 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 absorbent core, and the shape and size of the core wrap are not limited to the embodiment shown in FIG. 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, the position, shape and size of the plurality of recesses 140 in these regions, and the interval between adjacent recesses may be the same or different in two or more regions. .

FIG. 2 is an enlarged view of the region B of the absorber 100 shown in FIG. In FIG. 2, the size of the absorbent body in the width direction WD is L1 and the dimension in the length direction LD is L2 of the concave portion 140 when the skin surface side surface having the plurality of recessed portions 140 interspersed with the absorbent body 100 is viewed in plan. An open end 141 is shown, and a bottom 142 having a dimension L3 in the width direction WD and a dimension L4 in the length direction LD of the absorber is shown. The interval between the opening ends of adjacent recesses in the width direction WD of the absorber is indicated by L5, and the interval between the opening ends of adjacent recesses in the length direction LD of the absorber is indicated by L6.

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

FIG. 3B shows that at least one region having the predetermined high water-absorbing polymer content rate and average density of the absorbent body 100 is provided with a plurality of concave portions scattered on both the skin surface side surface and the non-skin surface side surface. It is typical sectional drawing which shows another embodiment of the absorber of this invention used. In FIG. 3B, a plurality of the same shape and size as those of the concave portions 140 provided on the surface opposite to the convex portions 145 between the plurality of concave portions 140 provided at a predetermined interval on the skin surface side surface. A recess is indicated by reference numeral 140 ′, and a protrusion located between the plurality of recesses 140 ′ is indicated by reference numeral 145 ′. The concave portion 140 ′ is recessed at a depth d ′ in the thickness direction TD of the absorber with the top surface of the convex portion 145 ′ positioned between adjacent concave portions as a reference plane. The bottom 142 ′ has a bottom surface 142a ′ substantially 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. It 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. A region adjacent to the concave portion 140 ′ of the convex portion 145 ′, in which the superabsorbent polymer particle 114 is present at a basis weight higher than the basis weight of the superabsorbent polymer particle in the concave portion 140 ′, is a reference number 145a. It is indicated by '. About the recessed part 140 'when the non-skin surface side surface having the plurality of recessed parts 140 interspersed with the absorbent body 100 is viewed in plan, the opening end 141' and the bottom part 142 'in the width direction WD and the length direction LD of the absorbent body The distance between the opening ends of adjacent recesses in the width direction WD and the length direction LD of the absorber is within the above-described range for the skin surface side, and the plurality of recesses 140 provided on the skin surface 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. Furthermore, at least one of the plurality of recesses 140 provided on the skin surface side surface may at least partially overlap with the plurality of recesses provided on the non-skin surface side surface in the thickness direction TD of the absorber. .

FIG. 4 is a plan view schematically showing an absorbent body 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 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 guiding portions 150R and 150L can be low-basis weight regions having lower basis weights than the peripheral regions of the deformation guiding portions 150R and 150L, respectively, thereby absorbing the absorbent body and thus the absorbent body incorporated therein. It becomes easy for a property article to bend | fold with the said deformation | transformation induction | guidance | derivation part as a base axis. The shape of a pair of deformation | transformation induction | guidance | derivation parts 150R and 150L can be set so that the absorbent article in which the absorber was incorporated may become easy to follow the three-dimensional shape of a wearer's wearing part. The absorbent body may include a recessed portion formed continuously or discontinuously in the deformation guide portion so that the absorbent article including the absorbent body has a better fit to the wearer. The basis weight of the deformation induction part is not particularly limited, but is preferably 30 to 80% by mass of the basis weight of the outer edge part 130.

FIG. 5 is a view for explaining an 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 configured by a low basis weight region. In the embodiment shown in FIG. 5, the low basis weight regions constituting the deformation guiding portions 150R and 150L have widths WR and WL in the width direction WD, respectively, 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 portion Ba is the smallest, and in the inclined portion Sl, the basis weight gradually increases as the distance from the bottom portion Ba increases. The low basis weight region can be formed, for example, according to the methods described in JP 2010-233839 A and JP 2016-123636 A of the same applicant.

FIG. 6 is a schematic plan view showing a developed state of the disposable diaper including the absorbent body of the present invention, and FIG. 7 schematically shows the disposable diaper shown in FIG. 6 when it is transformed into a predetermined shape. It is a perspective view. As shown in FIG. 6, the disposable diaper 1 has a shape whose outer shape is long in the length direction LD in a plan view, and a substantially central portion of the length direction LD is directed inward in the width direction WD. It has a narrow hourglass shape. In the present invention, the outer shape of the absorbent article is not limited to such an outer shape, and if the length dimension in the length direction L is longer than the width dimension in the width direction W, An arbitrary vertically long shape (for example, a rectangle, an ellipse, a bowl, etc.) can be used according to various applications. A disposable diaper 1 according to this embodiment includes a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and the absorbent body 4 of the present invention disposed between these sheets. . Further, the disposable diaper 1 includes a 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 leak-proof walls, and the front end of the side sheet in the width direction WD. And elastic members 6 and 6 extending in the length direction LD on the side. In addition, in the disposable diaper 1 shown in FIG. 7, the one end side of the length direction LD located below FIG. 6 is the abdomen side covering the wearer's abdomen, and the other end side of the length direction L located above is the wearer's abdomen. It is the dorsal side which covers a back part (buttock). Moreover, the disposable diaper 1 which concerns on this embodiment is what is called a tape-type disposable diaper with which a wearer is mounted | worn using the tape fastener 7 at the time of wear. The disposable diaper which is 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 top sheet 2 is disposed on the skin surface side of the absorbent body 4, and liquid excretion such as urine from the wearer is quickly absorbed or permeated to move toward the absorbent body 4. It is a permeable sheet-like member. In addition, in this embodiment, the surface sheet 2 is formed long in the direction along the length direction L of the disposable diaper 1. As the surface sheet 2, for example, any liquid permeable sheet such as a nonwoven fabric, a woven fabric, a synthetic resin film in which liquid permeable holes are formed, and a net-like sheet having a mesh can be used. From the viewpoints of properties, flexibility, touch, etc., it is preferable to use a nonwoven fabric. The back sheet 3 is disposed on the non-skin side of the disposable diaper 1 and is a liquid-impermeable sheet-like member that prevents liquid excretion discharged from the wearer from leaking out of the disposable diaper 1. It is. The back sheet 3 is bonded to each other with the top sheet 2 and the side sheets 5 and 5 and the absorber 4 sandwiched therebetween. For this bonding, for example, any bonding means such as bonding with a hot melt adhesive or bonding by various embossing treatments can be used. For example, the back sheet may be any liquid such as a waterproof 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. A permeable sheet can be used.

FIG. 8 illustrates an example of a manufacturing apparatus 800 that is used to manufacture an absorbent body according to an embodiment of the present invention having a plurality of recesses scattered on one of the skin surface side surface and the non-skin surface side surface. It is a schematic diagram for doing. In the present specification, the direction along the material or product conveyance 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 direction and the CD direction (that is, the vertical direction of the production line) is referred to as the TD direction. The manufacturing apparatus 800 includes a transport pipe 801 that transports an absorbent material including the opened hydrophilic fibers 8F and particulate superabsorbent polymer 8S, and a first laminate that is a precursor of an absorbent core of the absorbent body. 8, a rotatable suction drum 802, a core wrap continuous body unwinding roll 804 for unwinding a long core wrap continuous body 812 covering the outer peripheral surface of the first laminated body 811, and a pressing device 805. With. The pressing device 805 is for forming a plurality of concave portions 140 scattered on the skin surface side surface of the absorbent body, and a plurality of embossed pins (convex portions) protruding outward in the radial direction of the roll are shown in FIG. It includes a pair of rolls composed of an embossing roll 805a disposed on the outer peripheral surface corresponding to the positions and shapes of the regions A1c to A4c of the absorber 100 shown and an anvil roll 805b having a smooth outer peripheral surface. A plurality of concave mold members 803 disposed 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. The After the first laminated body 811 formed by the mold member 803 is transferred from the suction drum onto the core wrap continuum, the second laminated body 813 is formed by covering with the core wrap continuum. The second laminated body 813 is conveyed to the pressing device 805 and is compressed by the pressing device 805. In FIG. 8, the laminate passing through the nip between the embossing roll 805a and the anvil roll 805b of the pressing device 805 is indicated by reference numeral 814. The particulate superabsorbent polymer that can be used to form the precursor of the absorbent core may be any superabsorbent polymer that is generally used in absorbent bodies for absorbent articles. The particulate superabsorbent polymer is preferably such that the number percentage of particles having a particle size in the range of 150 μm to 850 μm is 95% or more.

Therefore, when the absorbent body is manufactured using the manufacturing apparatus 800, the first stacked body 811 is formed by stacking the absorbent material including the hydrophilic fibers 8F and the superabsorbent polymer particles 8S. The second step of forming the second laminated body 813 by covering the first laminated body 811 with the core wrap continuous body 812, and the second laminated body 813 is squeezed in the thickness direction by the squeezing device 805. Then, the third step of forming the third stacked body 815 by performing embossing is sequentially performed. In addition, the cutting device which cut | disconnects the 3rd laminated body 815 embossed with the pressing apparatus 805 to a desired shape in the downstream of the conveyance direction F rather than the pressing apparatus 805, and forms a single absorber (FIG. (Not shown). Furthermore, a front sheet laminating apparatus (not shown) for supplying and laminating a continuous surface sheet on the upper surface of the absorbent body to the manufacturing apparatus 800, and a back sheet laminating apparatus for laminating by supplying a back surface continuous body to the lower surface of the absorbent body 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 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 concave portions scattered on both the skin surface side surface and the non-skin surface side surface. FIG.
Similar to the manufacturing apparatus shown in FIG. 8, the manufacturing apparatus 800 ′ includes a transport pipe 801 that transports an absorbent material including the opened hydrophilic fibers 8F and the superabsorbent polymer 8S, and an absorbent core of the absorbent body. A rotatable suction drum 802 that forms a first laminated body 811 that is a precursor, and a core wrap continuous body for unwinding a long core wrap continuous body 812 that covers the outer peripheral surface of the first laminated body 811 A second squeeze comprising a pair of rolls comprising an unwinding roll 804 and a squeezing device 805 (first squeezing device), and further comprising an embossing roll 805a ′ and an anvil roll 805b ′ having a smooth outer peripheral surface. A device 805 'is provided. The embossing roll 805a 'and the anvil roll 805b' of the second pressing device 805 'are the same as the anvil roll 805b' and the embossing roll 805a of the first pressing device 805 with respect to the laminates 811, 813, 815 and 817, respectively. On the side. Manufacturing apparatus 800 'of embodiment shown in FIG. 9 forms the several recessed part dotted on the skin surface side of an absorber by pressing apparatus 805 (1st pressing apparatus), and pressing apparatus 805' (2nd pressing apparatus) A plurality of concave portions scattered on the non-skin surface side of the absorber is formed by the pressing device. In FIG. 9, the laminate passing through the nip between the embossing roll 805a ′ and the anvil roll 805b ′ of the pressing device 805 ′ is indicated by reference numeral 816, and the skin side surface and the non-skin side surface Is indicated by the reference numeral 817. When the absorbent body is manufactured using the manufacturing apparatus 800 ′, the first stacked body 811 is formed by stacking the absorbent material including the hydrophilic fibers 8F and the superabsorbent polymer particles 8S. A second step of forming the second laminate 813 by covering the first laminate 811 with the core wrap continuum 812, and the thickness direction of the second laminate 813 by the first pressing device 805 A third step of forming the third laminate 815 by embossing and embossing, and embossing the third laminate 815 in the thickness direction by the second pressing device 805 ′. Then, the fourth step of forming the fourth stacked body 817 is sequentially performed.

FIG. 10A is a three-view drawing of an example of embossed pins (convex portions) provided on the outer peripheral surface of the embossing roll. The embossed spin 90 shown in FIG. 10A includes a base 91 and a quadrangular pyramid-shaped apex 92, and is symmetrical twice with respect to the central axis in the direction perpendicular to the MD direction and the CD direction. The base 91 extends radially outward of the roll from a smooth reference surface (not shown) of the embossing roll, and the top 92 extends radially outward of the roll from the top of the base. Although the top 92 of the embossed spin illustrated in FIG. 10A has a quadrangular pyramid shape, the top 92 has a hemispherical shape or a semi-spheroid shape, a truncated cone shape, a pentagonal frustum, a hexagonal frustum, a heptagonal frustum. In addition, a polygonal frustum shape such as an octagonal frustum can be used. The base 91 of the embossed spin illustrated in FIG. 10A has a quadrangular prism or a truncated pyramid shape, but the shape of the base 91 may be, for example, a cylinder or a truncated cone, a pentagonal column, a hexagonal column, a The shape may be a polygonal prism shape such as a prism or octagonal prism, or a polygonal pyramid shape such as a pentagonal pyramid, hexagonal frustum, heptagonal pyramid, or octagonal pyramid. The embossing pins illustrated in FIG. 10A, top 92 has a top surface TS, side SS2 facing parallel to the side surface SS1, MD direction facing parallel to the CD direction, the bottom surface BS1 and height _{h 1,} the base top portion top surface in common with the bottom surface BS1, having a bottom surface BS2 and a height _{h 2.} 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 of LT1 in the CD direction and a length of 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 of LB1 in the CD direction and in the MD direction. It has a length of LB2. In FIG. 10A, for simplicity, the base 91 is shown as a rectangular parallelepiped. However, in the MD direction and the CD direction, the inclination angles α ₁ and β ₁ (that is, the angle formed by the side surface SS1 of the top portion 92 and the bottom surface BS1 and the top portion). The angles formed by the side surface SS2 and the bottom surface BS1 of the 92 are inclination angles α ₂ and β ₂ (that is, the angle formed by the side surface of the base and the bottom surface of the base parallel to the CD direction and the side surface of the base and the bottom surface of the base parallel to the MD direction). The base 91 is a cylinder or a truncated cone having a common top surface with the bottom surface of the top 92, or an n prism or an n truncated pyramid (n is an integer of 4 or more). Can be. The inclination angle α ₁ is preferably 10 to 60 degrees, and the inclination angle β ₁ is preferably 10 to 60 degrees. When α ₂ and β ₂ are 90 degrees, embossed spins 90 can be provided at a higher density on the outer peripheral surface of the embossing roll, so α ₂ and β ₂ are preferably 90 degrees. The height _{h 1} and the base of the height _{h 2} of the total h of the top portion ₍₌ h 1 + _{h 2)} is, 1 ~ 20 mm, preferably 2 ~ 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. There is a problem that an embossing roll having a large number of embossed spins where h exceeds 20 mm is expensive to manufacture. The height h ₁ at the top is preferably 0.2 to 2 mm. The height h _{2 of the} base is preferably 1.8 to 3.8 mm. The length LB1 of the top bottom surface BS1 in the CD direction is preferably 2 to 25 mm, more preferably 2 to 8 mm, and still more preferably 3 to 5 mm. The length LB2 of the top bottom surface BS1 in the MD direction is preferably 1 to 25 mm, more preferably 1.5 to 6 mm, and still more preferably 2 to 4 mm. The length LT1 in the CD direction of the top surface TS at the top is preferably 1 to 20 mm, more preferably 2 to 5 mm, and still more preferably 2.5 to 5 mm. The length LT2 in the MD direction of the top surface TS at the top is preferably 0.5 to 15 mm, more preferably 1 to 5 mm, and 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 mm ² , and still more preferably 5 to 20 mm ² . The distance between adjacent embossed spins in the CD direction and the MD direction, that is, the shortest distances D1 and D2 of the side surfaces of the bases of adjacent embossed spins are preferably 0.5 to 13 mm, more preferably 1 to 6 mm, still more preferably 1-5 mm. LT1, LT2, LB1, LB2, h ₁ , h ₂ , α ₁ , β ₁ , α ₂ , β ₂ , D1 and D2 and the size and shape of BS2 are the shape and size of the recess to be formed in the absorber. It can be determined according to the distance, 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 embossing roll is viewed in plan. For simplification, the embossed spin base is omitted in FIGS. 10B and 10C. FIG. 10B shows an embodiment in which a plurality of embossed spins have a quadrangular frustum-shaped top and are arranged in parallel at predetermined intervals D1 and D2 in the CD direction and MD direction, respectively. FIG. 10C shows an embodiment in which a plurality of embossed spins have an octagonal pyramidal top and are staggered, ie staggered. In FIG. 10C, the interval between the apexes adjacent in the CD direction is indicated by D1, and the interval between the apexes adjacent in the MD direction is indicated by D2. The interval between adjacent embossed spins is determined according to the interval between adjacent concave portions of the absorber. Unless the effects of the present invention are impaired, the plurality of embossed pins may be arranged in an arrangement other than the arrangement shown in FIGS. 10B and 10C. For example, the embossed spins can be arranged in a regular or irregular array so as to satisfy an embossed spin area ratio of 25 to 65% when the outer peripheral surface of the embossed spin is viewed in plan. In order to prevent the appearance of the absorber and the generation of locally high rigidity parts, it is preferable that the embossed pins are regularly arranged at regular intervals.

FIGS. 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 embossing roll is viewed in plan. As shown in FIG. 11A, the top surface of the top part has a rectangular shape with right angles of four corners, a shape with rounded corners as shown in FIG. 11B, and a chamfered corner as shown in FIG. 11C. It can have the shape that is made. The top surface of the top may be oval as shown in FIG. 11D. The top can be hemispherical or semi-spheroid. When the top surface of the embossed spin top has a shape with a rounded chamfered corner or a shape with a rounded chamfered corner as shown in FIGS. 11B to 11D, refer to FIG. However, as will be described below, when embossing the laminated body, when the top of the embossed pin hits the laminated body, the pressure applied to the laminated body can be dispersed, and damage to the core wrap can be prevented.

FIG. 12 schematically shows a further example of embossed spin. The embossed spin 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 top shapes TS and R chamfers 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 Have The top surface TS of the top portion 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 portion has a length of LB1 in the CD direction and a length of LB2 in the MD direction. In FIG. 11, for simplicity, 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 portion 92 and the bottom surface BS1 are the side surface and bottom surface of the base portion. The base 91 is an n-prism or an n-pyramidal frustum having a top surface common to the bottom surface of the top 92 (n is an integer of 4 or more) under the condition that the angles α ₂ and β ₂ formed by Can do. There is a problem that an embossing roll having a large number of embossed spins where h exceeds 20 mm is expensive to manufacture. When the embossing roll having a plurality of embossed pins exemplified in FIG. 11 is used to perform the pressing step, the effect of preventing the core wrap from being damaged when the top of the embossed pin comes into contact with the laminate is more effective. It can be further enhanced.

FIG. 13 is a schematic enlarged view of the nip between the embossing roll 805a and the anvil roll 805b of the pressing device 805 in FIG. FIG. 13 shows an emboss pin (convex portion) in which one side of the laminate 814 has a base 91 and a top 92 when the laminate 814 conveyed in the conveyance direction F passes through the nip between the embossing roll 805a and the anvil roll 805b. ) Shows a process in which the concave portion is formed by being pressed by 90. In the manufacturing method of the absorbent body of the present invention, the embossed spin 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 follows the rotation of the embossed spin 805a and the anvil roll 805b. When the top 92 contacts the surface of the stacked body 814, the angle θ formed by the side surface SS of the top 92 and the surface of the stacked body 814 on the downstream side in the transport direction of the stacked body is in the range of 0 to 60 degrees. The angle θ is preferably 0 to 30 degrees. The greater the angle θ, the lower the effect of preventing breakage of the core wrap because the pressing pressure on the laminate is less likely to be dispersed when the top of the embossed pin contacts the laminate.

The absorbent article of the present disclosure is not particularly limited, for example, an absorbent article that mainly absorbs urine, for example, a disposable diaper, a urine collection pad, an urination sheet for animals, etc. Examples of the property article include sanitary napkins and panty liners.

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

(1) Production of absorber [Examples 1 to 10]
By using the manufacturing apparatus shown in FIG. 8, a 115 mm long x 330 mm wide absorbent material containing a basis weight pulp (NB416 manufactured by Weyerhauser) and SAP particles (SA60S manufactured by Sumitomo Seika Co., Ltd.) shown in Table 1 below is used. 1 laminate (corresponding to the precursor of the absorbent core) is formed, and the first laminate is coated with an SMS nonwoven fabric (basis weight 10 g / m ² ) as a core wrap to form a second laminate, The second laminate is squeezed at a nip interval of 0.5 to 0.7 mm and a nip pressure of 0.15 MPa by a pressing device having a pair of rolls, that is, an embossing roll and an anvil roll in which a plurality of embossed pins are arranged on the outer peripheral surface. And it cut | disconnected to the size of length 130mm x width 360mm, and produced the absorber. The speed at which the second laminate passed through the nip was about 5 m / s. The embossing pins of the embossing rolls used in Examples 1 to 10 had an octagonal columnar base as shown in FIG. The top of the embossed spin of the emboss 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 embossing rolls used in Examples 1 to 3, as shown in FIG. 10C, the embossed pins were arranged in a staggered pattern. In the embossing rolls used in Examples 4 to 10, as shown in FIG. 10B, the embossed pins were arranged in a parallel pattern in the MD direction and the CD direction. Table 1 shows the dimensions of the embossed spins of the embossing rolls used in Examples 1 to 10 (that is, the top surface CD direction length LT1, the top surface MD direction length LT2, the bottom surface CD direction length LB1. , MD direction length LB2 of the bottom surface) and the shortest distances D1 and D2 between adjacent embossed spins in the CD direction and MD direction. In the CD direction and the MD direction, the angles α ₁ and β ₁ formed by the top side surface and the bottom surface are both 30 degrees, and the angles α ₂ and β ₂ formed by the base side surface and the bottom surface are both 90 degrees. It was. Therefore, the area of the bottom surface of the base portion of the embossed spin is equal to the area of the bottom surface of the top portion. When the angles α ₂ and β ₂ are both 90 degrees, the area ratio S _r of the bottom surface of the base of the embossed spin is LB1 and LB2 respectively in the CD direction and the MD direction of the bottom surface of the top. When the shortest intervals in the CD direction and the MD direction are expressed as D1 and D2, respectively, in the staggered arrangement, the formula (1):
S _r = (LB1 × LB2) / {2 × (LB1 + D1) × (LB2 + D2)}
For a parallel array, equation (2):
S _r = (LB1 × LB2) / {(LB1 + D1) × (LB2 + D2)}
Can be asked according to.

[Comparative Examples 1 to 3]
Absorbers of Comparative Examples 1 to 3 were prepared 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 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 absorbent bodies 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. Example 1 except that an embossing roll in which a square frustum-shaped embossed pin having an angle of 45 degrees with each other is provided on the outer peripheral surface at intervals of 2.70 mm in the CD direction and 4.5 mm in the MD direction is used. It was produced in the same manner as in. In addition, the shape and dimension of this embossed spin correspond to the protrusion formed in 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 superabsorbent polymer in the absorber was examined by observing the internal structure of the absorber in a nondestructive manner 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 Beam Sense Co., Ltd., the software used for synthesizing the captured images was Beamsense CT, and the software used for analyzing the captured images was Volume Extractor. The tube voltage was 40 kV, the tube current was 100 μA, and the imaging time per time was 1 second. The absorber sample is mounted 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 photographing once every 0.5 degrees. 720 images were synthesized. From the X-ray CT composite image, when the absorber sample is viewed in plan, two pairs of adjacent embossed recesses in the length direction of the absorber sample are randomly sampled, and the basis weight of the superabsorbent polymer in these embossed recesses is sampled. The average value (b1) of quantity was calculated | required. Furthermore, the average value (b2) of the basis weight of the superabsorbent polymer of the convex part located between the 10 pairs of two embossed concave parts sampled at random was obtained. The percentage of b1 with respect to b2, that is, a value of 100 × b1 / b2 was obtained. The value of 100 × b1 / b2 for Examples 1 to 10 is shown in Table 2. In Comparative Examples 1 to 6, no bias was observed in the distribution of the superabsorbent polymer by X-ray CT observation.

[Rigidity test]
A sample having a size of 20 mm × 50 mm was punched out 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 (manufacturer diameter: 50 mm, pressure: 294 Pa) manufactured by Ozaki Mfg. Co., Ltd. Attach a digital force gauge (FGP-2 manufactured by Nidec Sympo Co., Ltd.) to a force gauge stand (FGS-50S manufactured by Nidec Sympo Co., Ltd.) and bend it at the probe mounting part of the digital force gauge. A pressing part (indenter) of a jig (GA-10N manufactured by Imada Co., Ltd.) was attached, and the base part of the three-point bending jig was placed on a measurement table of a 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 base of the bending jig so that the tip of the pressing part (indenter) of the bending jig was in contact with the center 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 the stiffness value. Tables 3 to 5 show the evaluation results of rigidity together with the density of the absorbent body determined from the size, mass and thickness of the absorbent body.

A graph of density (g / cm ³ ) versus stiffness (N) for the absorbers of Examples 1-3 embossed using an embossing roll according to the present invention is shown in FIG. A graph of density (g / cm ³ ) versus stiffness (N) for Comparative Examples 1 to 3 embossed using a flat press is shown in FIG. A graph of density (g / cm ³ ) versus stiffness (N) for the absorbers of Comparative Examples 4-6 embossed using an embossing roll is shown in FIG.

14 to 16 and Table 8, in Examples 1 to 3, a 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). ³ or 0.3 g / rigidity cm ³ less than the area) is high, the standard absorber density is relatively high region (i.e., area under the absorber density 0.4 g / cm ³ or more 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 with extremely high rigidity.

[Tactile evaluation]
For the samples of Examples 1 to 3 and Comparative Examples 1 to 6, the tactile sensation was sensory-evaluated by 10 skilled panelists, and the evaluation results were graded by 1 to 3 grades.
Grade 1: Hard spot is not recognized, which is preferable for use in baby diapers.
Grade 2: Slight hard spots were observed, but acceptable for use in baby diapers.
Grade 3: It contains a very hard part and is not suitable for use in baby diapers.
A sample rated “1” was given a “0” rating, a sample rated “2” was given a “1” rating, and a sample rated “3” was given a “2” rating. Points were assigned and the total score was calculated. The smaller the sum of the evaluation points, the better the tactile sensation and the more preferable it is for use in baby diapers.

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

DESCRIPTION OF SYMBOLS 1 Disposable diaper 2 Liquid-permeable surface sheet 3 Liquid- impermeable back sheet 5,5 Side sheet 6,6 Elastic member 7 Tape fastener 4,100,100 'Absorbent body 110 Absorbing core 114, 8S Superabsorbent polymer particle 116,8F hydrophilic fiber 120 core wrap 130 outer edge portion 140,140 ′ concave portion 141,141 ′ concave end opening 142 concave bottom portion 142a, 142a ′ bottom bottom surface 142b, 142b ′ bottom inclined surface 145,145 ′ convex portion 145a , 145a ′ Region adjacent to the concave portion 146 Convex portion 150R, 150L Deformation guide portion 800, 800 ′ Absorber manufacturing device 801 Conveying pipe 802 Suction drum 803 Concave mold member 804 Unwinding roll 805, 805 ′ Squeezing device 805a , 805a 'Embossing roll 80 5b, 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 (7)

1. An absorbent core containing hydrophilic fibers and particulate superabsorbent polymer; and a core wrap covering the absorbent core; a length direction, a width direction and a thickness direction; a skin surface side surface and a non-skin surface An absorbent body for absorbent articles having a side surface,
   The absorber is at least one region having a high water-absorbing 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 having at least one region having a plurality of recessed portions interspersed with each other and a protruding portion located between the plurality of recessed portions, and the length of the absorber when the absorber is viewed in plan view. The average basis weight of the superabsorbent polymer in the two adjacent concave portions is the two adjacent concave portions in the direction and the convex portion located between the two adjacent concave portions. Less than the basis weight of the superabsorbent polymer in the convex part,
   Absorber characterized by.
2. The absorbent body according to claim 1, wherein an average basis weight of the superabsorbent polymer in the two concave portions is 15% or more less than a basis weight of the superabsorbent polymer in the convex portion.
3. The area ratio in plan view of the plurality of recesses in the at least one region of the absorbent body is independently 25 to 65% on one or both of the skin side surface and the non-skin side surface. Item 3. The absorber according to Item 1 or 2.
4. The plurality of recesses each have a rectangular shape with an area of 2 to 50 mm ^{2 in} plan view, and the interval between adjacent recesses in the length direction of the absorber is 0.5 to 10 mm. The absorber as described in any one of these.
5. The absorbent body according to any one of claims 1 to 4, wherein the absorber has a pair of deformation guide portions extending in a predetermined direction, and the plurality of concave portions are present between the pair of deformation guide portions. Absorber.
6. An absorbent article comprising the absorber according to any one of claims 1 to 5.
7. It is a manufacturing method of the absorber for absorptive articles according to claim 1,
   (A) covering the absorbent core with a core wrap to form a laminate having a first surface and a second surface respectively corresponding to the skin surface side surface and the non-skin surface side surface of the absorber; and (b) The process of forming the absorber of Claim 1 by pressing one or both of the 1st surface and the 2nd surface of the said laminated body with the embossing roll which rotates in the conveyance direction of the said laminated body, conveying the said laminated body. ,
   Including
   The embossing roll has at least one region provided with a plurality of interspersed convex portions on its outer peripheral surface,
   The plurality of interspersed convex portions on the outer peripheral surface of the embossing roll each include a base and a hemispherical or n-pyramidal frustum shape (n is an integer of 4 or more),
   In the step (b), an angle formed between a side surface of the top portion on the downstream side in the transport direction and the laminated body when the top portion contacts the surface of the laminated body according to the rotation of the embossing roll is 0 to 60 degrees. Is within the range of
   Manufacturing method of absorber.

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