WO2022118903A1

WO2022118903A1 - Multilayer body

Info

Publication number: WO2022118903A1
Application number: PCT/JP2021/044170
Authority: WO
Inventors: 海紗生谷口
Original assignee: 住友精化株式会社
Priority date: 2020-12-04
Filing date: 2021-12-01
Publication date: 2022-06-09
Also published as: CN116583251A; JPWO2022118903A1

Abstract

The purpose of the present invention is to provide a multilayer body which is useful for an absorbent article that exhibits excellent absorption rate and side leakage prevention performance with respect to multiple exposures to a liquid. A multilayer body which comprises: a liquid-permeable first sheet, a liquid-absorbing intermediate sheet, and a second sheet, said sheets having a shape that has a longitudinal direction; and a water-absorbing resin layer that is interposed at least between the first sheet and the intermediate sheet. With respect to this multilayer body, the intermediate sheet comprises a region A and a region B, which have a shape that has a longitudinal direction; and the region A and the region B satisfy at least one of the relations (1) and (2) described below, while satisfying the relation (3) described below. (1) The region A has a low density, and the region B has a high density; and if the density of the region B is taken as 1, the ratio of the density of the region A is 0.45 or less. (2) The region A is a projected part that protrudes toward the water-absorbing resin layer, and the region B is a recessed part; and the height of the projected part is 0.25 mm or more. (B) The region B is positioned inside the longitudinal ends of the intermediate sheet.

Description

Laminate

The present invention relates to a laminated body. More specifically, the present invention relates to a laminate having improved liquid permeation rate and lateral leakage prevention.

For body fluid-absorbing articles such as paper diapers, urine pads, and sanitary napkins, the absorbent layer that absorbs the liquid, the liquid-permeable surface sheet arranged on the side in contact with the body, and the side opposite to the side in contact with the body. Consists of a laminate containing a liquid impermeable back sheet arranged in.

One of the essential properties representing the performance of a body fluid-absorbing article is the rate of liquid absorption. So far, various improvements have been made to body fluid-absorbing articles so that liquids can be absorbed more quickly.

For example, Patent Document 1 has a water-permeable front surface sheet facing the body side, a back surface side sheet facing the clothes side, and a function of being encapsulated in the front surface side sheet and the back surface side sheet to absorb body fluids. In an absorbent article provided with a liquid-absorbent core, the fiber density on the side facing the liquid-absorbent core is higher than the fiber density on the side facing the surface-side sheet between the surface-side sheet and the liquid-absorbent core. An absorbent article provided with a large body fluid permeable sheet (second sheet) has been proposed, and according to this absorbent article, the body fluid that has passed through the surface side sheet and reached the upper surface of the body fluid permeable sheet has a fiber density. It has been shown that it moves so as to be guided to the higher gradient side (liquid absorbing core side), so that it is absorbed quickly.

Japanese Patent Application Laid-Open No. 2003-210523

In the absorbent article described in Patent Document 1, although the absorption rate has been studied, in view of the actual use conditions in which the liquid can be exposed to one absorbent article multiple times, the second and subsequent times are performed. For exposed liquids, gel blocking slows the absorption rate, reduces absorbability and tends to cause lateral leakage.

Therefore, the present invention exhibits an excellent absorption rate even when exposed to a plurality of liquids and is also excellent in the property of reducing the risk of lateral leakage (hereinafter, the characteristic of reducing the risk of lateral leakage is "lateral leakage prevention property". Also described.) It is an object of the present invention to provide a laminate useful for an absorbent article.

As a result of diligent studies, the present inventors have provided a liquid-absorbent sheet in the material constituting the laminate, and the liquid-absorbent sheet has a relatively coarser density than other regions. Alternatively, it has been found that by configuring the convex region on the water-absorbent resin side to be elongated at a predetermined position, it is possible to exhibit an excellent absorption rate and lateral leakage prevention property even when exposed to a plurality of liquids. rice field. The present invention has been completed by further studies based on this finding.

That is, the present invention provides the inventions of the following aspects.
Item 1. Includes a liquid-permeable first sheet, a liquid-absorbent intermediate sheet, and a second sheet having a shape having a longitudinal direction, and at least a water-absorbent resin layer interposed between the first sheet and the intermediate sheet. It ’s a laminated body,
The intermediate sheet includes a region A having a shape having a longitudinal direction and a region B.
A laminated body in which the region A and the region B satisfy at least one of the following relationships (1) and (2) and satisfy the following relationship (3).
(1) When the region A has a low density and the region B has a high density, and the density of the region B is 1, the ratio of the density of the region A is 0.45 or less.
(2) The region A is a convex portion that is convex toward the water-absorbent resin layer, and the region B is a concave portion, and the height of the convex portion is 0.25 mm or more.
(3) The region B is located inside the longitudinal end of the intermediate sheet.
Item 2. Item 2. The laminate according to Item 1, wherein the region A and the region B satisfy the relationship of the above (1) and the above (2).
Item 3. Item 2. The laminate according to Item 1 or 2, wherein the region A includes a linear portion extending in a direction including a longitudinal direction of the intermediate sheet.
Item 4. Item 2. The laminate according to any one of Items 1 to 3, wherein the region A includes a linear portion extending substantially parallel to the longitudinal direction of the intermediate sheet.
Item 5. Item 4. The laminate according to Item 4, wherein the region B includes a streak portion arranged on the short center line of the intermediate sheet.
Item 6. Item 2. The laminate according to any one of Items 1 to 5, wherein a plurality of the regions A and the regions B are alternately arranged in the lateral direction of the regions.
Item 7. Item 6. The laminated body according to Item 6, which includes a plurality of linear portions in which the region A and the region B are arranged in parallel.
Item 8. Item 2. The laminate according to any one of Items 1 to 7, wherein the region B is located inside the short end of the intermediate sheet.
Item 9. An absorbent article comprising the laminate according to any one of Items 1 to 8.

According to the present invention, there is provided a laminate useful for an absorbent article that exhibits an excellent absorption rate and lateral leakage prevention property even when exposed to a plurality of liquids.

The cross-sectional view of the 1st Embodiment of the laminated body of this invention is shown schematically. The external view of a part (a part including a longitudinal end) of the intermediate sheet of the laminated body of FIG. 1 is schematically shown. An exploded view of the part of the laminated body of FIG. 1 is schematically shown. The state in which the laminate of FIG. 1 was first exposed to liquid during use is schematically shown in an exploded view as in FIG. The external view of the intermediate sheet used in the 2nd Embodiment of the laminated body of this invention is schematically shown. An exploded view of the laminated body of the second embodiment is shown in the same format as FIG. The state in which the laminated body 10a of FIG. 6 was first exposed to liquid during use is schematically shown in an exploded view as in FIG. The external view of the intermediate sheet used in the 3rd Embodiment of the laminated body of this invention is schematically shown. The external view of the intermediate sheet used in the 4th Embodiment of the laminated body of this invention is schematically shown. The external view of the part (the part including the short end) of the intermediate sheet used in the 5th Embodiment of the laminated body of this invention is schematically shown. Some examples of the shapes of regions A and B are shown schematically. Specific examples (examples) of the shapes of the regions A and B are shown. Specific examples (examples) of the shapes of the regions A and B are shown. Specific examples (comparative examples) of the shapes of the regions A and B are shown. Specific examples (comparative examples) of the shapes of the regions A and B are shown. Specific examples (comparative examples) of the shapes of the regions A and B are shown.

[1. Structure of laminated body]
The laminate of the present invention has a shape having a longitudinal direction, and has a liquid-permeable first sheet, a water-absorbing intermediate sheet, and a second sheet, and water absorption interposed between at least the first sheet and the intermediate sheet. A laminate comprising a sex resin layer; the intermediate sheet comprises a longitudinally shaped region A and a region B; the regions A and B are described in (1) and (2) below. Of the above, at least one of the relationships is satisfied, and the relationship of the following (3) is satisfied: (1) When the region A has a low density and the region B has a high density, and the density of the region B is 1. The density ratio of the region A is 0.45 or less. (2) The region A is a convex portion that is convex toward the water-absorbent resin layer, and the region B is a concave portion. It is characterized in that the height is 0.25 mm or more, and (3) the region B is located inside the longitudinal end of the intermediate sheet. With such a structure, the laminate of the present invention can exhibit an excellent absorption rate even with a plurality of liquid exposures. Hereinafter, the laminated body of the present invention will be described in detail.

[1-1. First Embodiment]
FIG. 1 schematically shows a cross-sectional view of a first embodiment of the laminated body of the present invention. FIG. 1 shows a cross-sectional view of a laminated body cut along a plane perpendicular to the longitudinal direction thereof. FIG. 2 schematically shows an external view of a part (a part including a longitudinal end) of the intermediate sheet of the laminated body of FIG. FIG. 3 schematically shows an exploded view of the part of the laminated body of FIG. The laminate 10 shown in FIGS. 1 and 3 has a liquid-permeable first sheet 20, a liquid-absorbing intermediate sheet 30 and a second sheet 40, which have a shape having a longitudinal LD, and at least a second sheet. 1 Includes a water-absorbent resin layer 51 interposed between the sheet 20 and the intermediate sheet 30. In the following, the stacking direction of the laminated body 10 is also referred to as “stacking direction LMD10”. The laminated body 10 also includes another water-absorbent resin layer 52 between the intermediate sheet 30 and the second sheet 40. Although not shown, an adhesive layer may be interposed between the water-absorbent resin layer 51 and the intermediate sheet 30 and / or between the water-absorbent resin layer 52 and the second sheet 40.

In the laminated body 10 of the present embodiment, as shown in FIGS. 1 to 3, the intermediate sheet 30 has a low density region A as a region A having a shape having the longitudinal LD-A (hereinafter, the low density region A is used as a region A). It also has a “low density region Al”) and a high density region (hereinafter, the high density region B is also referred to as a “high density region Bh”) as the region B, and has a high density region Bh. Is located inside the longitudinal end LE of the intermediate sheet 30.

The low density region Al is configured such that the ratio of the density of the low density region Al is 0.45 or less when the density of the high density region Bh is 1. From the viewpoint of further enhancing the absorption rate and / or the side leakage prevention property for several liquid exposures, the ratio is preferably 0.42 or less, more preferably 0.41 or less, still more preferably 0.4 or less. It is more preferably 0.3 or less, still more preferably 0.2 or less, and particularly preferably 0.12 or less. The lower limit of the ratio range is not particularly limited and may differ depending on the material and / or treatment of different densities of the intermediate sheet 30, but the absorption rate and / or lateral leakage prevention property to several liquid exposures are further enhanced. From the viewpoint, for example, 0.05 or more, preferably 0.08 or more can be mentioned.

Specific examples of the density of the low density region Al include 100 kg / m ³ or less. From the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property for several liquid exposures, the specific density of the low density region Al is preferably 60 kg / m ³ or less, more preferably 50 kg / m ³ or less. , More preferably 45 kg / m ³ or less, still more preferably 40 kg / m ³ or less, still more preferably 35 kg / m ³ or less, still more preferably 28 kg / m ³ or less, and particularly preferably 20 kg / m ³ or less. The lower limit of the specific density range of the low density region Al is not particularly limited as long as water retention can be guaranteed, and examples thereof include 16.5 kg / m ³ or more, preferably 18 kg / m ³ or more.

The method of making the density different in the intermediate sheet 30 is not particularly limited. Since the intermediate sheet 30 is liquid permeable, it has spaces or holes that communicate with each other in the thickness direction. Therefore, the method of making the densities different is as long as the volume occupied by these spaces or holes can be physically reduced. good. Specific methods include a method of compressing the dough of the intermediate sheet 30 at a place where the high-density region Bh should be provided, a method of fine-graining at the place where the high-density region Bh should be provided, and a method where the low-density region Al should be provided. Examples thereof include a method of producing a dough for the intermediate sheet 30 so that the thickness becomes coarse.

The fact that the high-density region Bh is located inside the longitudinal end LE of the intermediate sheet 30 means that there is no portion where the high-density region Bh reaches the longitudinal end LE of the intermediate sheet 30, and the entire high-density region Bh is It means that the intermediate sheet 30 is arranged inward in the in-plane direction from both longitudinal ends LE. That is, both longitudinal end LE portions of the intermediate sheet 30 are composed of the low density region Al.

By providing the intermediate sheet 30 with the low density region Al at a predetermined position in a predetermined shape as described above, an excellent absorption rate is exhibited even with a plurality of liquid exposures. The mechanism considered as the reason why such an excellent absorption rate can be obtained will be described with reference to FIG. FIG. 4 is an exploded view of the laminate 10 in a state of being first exposed to liquid during use (hereinafter, the laminate 10 in this state is also referred to as “laminate 10 ′”) in the same manner as in FIG. Shown schematically in.

First, in the laminated body 10, the intermediate sheet 30 has a space or a hole communicating with each other in the thickness direction and is in direct contact with the water-absorbent resin layer 51. Therefore, in the low density region Al of the intermediate sheet 30, the space is described above. Alternatively, it is considered that a part of the water-absorbent resin particles constituting the water-absorbent resin layer 51 is embedded in the pores. Even in the high-density region Bh of the intermediate sheet 30, some of the water-absorbent resin particles constituting the water-absorbent resin layer 51 may be invaded, but due to the density difference between the two regions, the low-density region Al is larger. It is considered that the water-absorbent resin particles of the above are invaginated.

When the laminated body 10 is exposed to the liquid from the first sheet 20 side, the liquid moves in the laminating direction LMD 10 and reaches the intermediate sheet 30. Since the intermediate sheet 30 is provided with the low density region Al and the high density region Bh as described above, more water is diffused in the low density region Al. Therefore, more water-absorbent resin particles trapped in the low-density region Al absorb more water more preferentially (ie, earlier after the laminate 10 is exposed to liquid). It expands by doing. That is, in the low-density region Al, the water-absorbent resin particles that first absorb water and expand are localized. As a result, there is a difference in the expansion rate of the water-absorbent resin particles corresponding to the positions of the low-density region Al and the high-density region Bh of the intermediate sheet 30 in the entire water-absorbent resin layer 51. Specifically, as schematically shown in FIG. 4, in the water-absorbent resin layer 51, the portion 51A corresponding to the low-density region Al of the intermediate sheet 30 expands more than the portion 51B corresponding to the high-density region Bh. (The water-absorbent resin layer 51 that has absorbed the initially exposed liquid is also particularly referred to as "water-absorbent resin layer 51'"). The larger expanded portion 51A corresponds to the shape having the longitudinal LD-A of the low density region Al, and forms a shape having the same longitudinal LD-A, that is, a convex portion (hereinafter, the larger expanded portion 51A). The portion 51A is also referred to as a “convex portion 51A”, and the portion 51B that is not expanded to the size of the convex portion 51A and is lowered is also referred to as a “concave portion 51B”).

When the laminate 10'is further exposed to the next liquid, a part of the liquid that has reached the water-absorbent resin layer 51'flows through the concave portion 51B along the longitudinal direction of the convex portion 51A. That is, when the liquid absorbed by the laminated body 10'is absorbed by the water-absorbent resin layer 51'after moving in the laminating direction LMD10, the liquid is absorbed by the laminated body 10'along the longitudinal direction LD-A of the convex portion 51A. Move so that it spreads in the in-plane direction. In this way, the convex portion 51A formed by the first liquid exposure spreads the absorbed liquid in the laminated body 10'without concentrating it on the portion reaching the water-absorbent resin layer 51', thereby expanding the water-absorbent resin. Maximize the area of contact between layer 51'and the liquid. It is considered that this makes it possible to improve the absorption rate. Further, the property of not concentrating the absorbed liquid in a specific place may contribute to reducing the amount of reversion of the liquid in the place. In addition, since the high-density region Bh is arranged so as to be located inside the longitudinal end LE of the intermediate sheet 30, the recess 51B in the water-absorbent resin layer 51'is also formed inside the longitudinal end LE. Therefore, even for the liquid that has reached the vicinity of the longitudinal end LE, the convex portion 51A of the longitudinal end LE acts as a physical barrier to dam the liquid. In this way, the risk of leakage (that is, lateral leakage) from the longitudinal end LE is also reduced.

In the above description, the "first liquid exposure" and the "next liquid exposure" may be continuous or intermittent.

[1-2. Second Embodiment]
FIG. 5 shows an intermediate sheet used in the second embodiment of the laminated body of the present invention in the same format as in FIG. Further, FIG. 6 shows an exploded view of the laminated body of the second embodiment in the same format as that of FIG. The laminated body 10a shown in FIG. 6 is the same as the laminated body 10 of the first embodiment described above, except that the intermediate sheet 30 is changed to the intermediate sheet 30a.

The intermediate sheet 30a used in the present embodiment has a region A having a shape having LD-A in the longitudinal direction, which forms a convex portion that is convex toward the water-absorbent resin layer (hereinafter, the region A that forms the convex portion is "convex". (Also referred to as "part region A +") and a region forming a concave portion (that is, a concave portion with respect to the convex portion region A +) as the region B (hereinafter, the concave region B is also referred to as "recessed region B-"). The recessed region B-is located inside the longitudinal end LE of the intermediate sheet 30a.

The height h of the convex portion region A + (height from the lowest portion of the concave portion region B- on the same surface side as the convex portion region A + to the highest portion of the convex portion) is 0.25 mm or more. It is configured in. From the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property for several liquid exposures, the height h is preferably 0.35 mm or more, more preferably 0.45 mm or more, still more preferably 0.6 mm. As mentioned above, 0.7 mm or more is more preferable. The upper limit of the height h range is not particularly limited, and examples thereof include 1 mm or less, preferably 0.9 mm or less.

The density of the intermediate sheet 30a in the present embodiment is substantially the same in the convex region A + and the concave region B−.

The method of providing the convex region A + and the concave region B- in the intermediate sheet 30a is not particularly limited. For example, a method of producing an intermediate sheet 30a by a watermarking technique using a substrate having concave portions and convex portions corresponding to the convex portion region A + and the concave portion region B-, respectively, a method of preparing the intermediate sheet 30a material in a block shape and forming an uneven shape. Examples thereof include a method of slicing so as to be exposed and cutting into an intermediate sheet 30a.

Even if the intermediate sheet 30a is provided with the convex region A + at a predetermined position in a predetermined shape as described above, an excellent absorption rate is exhibited against a plurality of liquid exposures. The mechanism considered as the reason why such an excellent absorption rate can be obtained will be described with reference to FIG. 7. FIG. 7 is an exploded view of the laminated body 10a in a state of being first exposed to liquid at the time of use (hereinafter, the laminated body 10a in this state is also referred to as “laminated body 10a'”) in the same manner as in FIG. Shown schematically in.

First, in the laminated body 10a, since the intermediate sheet 30a has a space or a hole communicating with each other in the thickness direction and is in direct contact with the water-absorbent resin layer 51, the convex region A + of the intermediate sheet 30a is a water-absorbent resin. It is considered that a part of the water-absorbent resin particles constituting the water-absorbent resin layer 51 has invaded the space or the hole by biting into the layer 51. A part of the water-absorbent resin particles constituting the water-absorbent resin layer 51 may be invaded even in the concave region B- of the intermediate sheet 30a, but the convex region A + is larger due to the height difference between the two regions. It is considered that the water-absorbent resin particles of the above are invaginated.

When the laminated body 10a is exposed to the liquid from the first sheet 20 side, the liquid moves in the laminating direction LMD 10 and reaches the intermediate sheet 30a. Since the intermediate sheet 30a is provided with the convex region A + and the concave region B− as described above, the liquid contacts the convex region A + earlier and diffuses faster in the convex region A +. Therefore, more water-absorbent resin particles trapped in the convex region A + absorb more water more preferentially (ie, earlier after the laminate 10a is exposed to liquid). It expands by doing. That is, in the convex region A +, the water-absorbent resin particles that first absorb water and expand are localized. As a result, there is a difference in the expansion coefficient of the water-absorbent resin particles corresponding to the positions of the convex portion region A + and the concave portion region B- of the intermediate sheet 30a in the entire water-absorbent resin layer 51. Specifically, as schematically shown in FIG. 7, in the water-absorbent resin layer 51', the portion 51A corresponding to the convex portion region A + of the intermediate sheet 30a is larger than the portion 51B corresponding to the concave portion region B-. Inflate. As a result, as in FIG. 4 of the first embodiment, a convex portion 51A having a shape having the LD-A in the longitudinal direction and a concave portion 51B which is not expanded to the size of the convex portion 51A and is lowered are generated.

Therefore, when the laminated body 10a'is further exposed to the next liquid, the liquid absorbed by the laminated body 10' is laminated along the longitudinal direction LD-A of the convex portion 51A, as in FIG. 4 of the first embodiment. By moving the body 10'so as to spread in the in-plane direction, it is considered possible to maximize the area of contact between the water-absorbent resin layer 51'and the liquid and improve the absorption rate. Further, the property of not concentrating the absorbed liquid in a specific place may contribute to reducing the amount of reversion of the liquid in the place, as in the first embodiment. In addition, since the convex portion 51A closest to the longitudinal end LE serves as a physical barrier, the risk of leakage (that is, lateral leakage) from the longitudinal end LE is reduced, as in the first embodiment.

[1-3. Third Embodiment]
FIG. 8 shows the intermediate sheet 30b used in the third embodiment of the laminated body of the present invention in the same format as in FIG. The laminated body of the third embodiment is the same as the laminated body 10 of the first embodiment described above, except that the intermediate sheet 30 is changed to the intermediate sheet 30b.

The intermediate sheet 30b used in the present embodiment has both the characteristics of the intermediate sheet 30 used in the first embodiment and the characteristics of the intermediate sheet 30a used in the second embodiment ((1) to (3) above. ) Satisfies the relationship). That is, the intermediate sheet 30b is a region A having a shape having LD-A in the longitudinal direction, which has a low density and a convex portion that is convex toward the water-absorbent resin layer (hereinafter, a region A that has a low density and a convex portion). Is also referred to as "low density / convex region Al +"), and as the region B, a high-density and concave region (that is, a concave portion with respect to the convex portion) (hereinafter, a high-density and non-convex region B). Also referred to as "high density / recessed region Bh-"), the high density / recessed region Bh-is located inside the longitudinal end LE of the intermediate sheet 30b.

Regarding the ratio of the density of the low density / convex region Al + when the density of the high density / concave region Bh− in the intermediate sheet 30b is 1, the density of the high density region Bh in the intermediate sheet 30 used in the first embodiment. Is the same as the ratio of the density of the low density region Al when. Further, the height h of the low density / convex region Al + in the intermediate sheet 30b is the same as the height h of the convex region A + in the intermediate sheet 30a used in the second embodiment.

Further, the density of the low density / convex region Al + in the intermediate sheet 30b is the same as the density of the low density region Al in the intermediate sheet 30 used in the first embodiment.

The method of providing the intermediate sheet 30b with a low-density and convex region and a high-density and concave region is not particularly limited. Preferably, an embossing method is used in which the fabric of the intermediate sheet 30b is compressed in the thickness direction from one side at a place where a region forming a high density and a recess is to be provided.

Since the laminated body of the third embodiment uses the intermediate sheet 30b having the above-mentioned characteristics, when the liquid is absorbed, the water-absorbent resin layer is shown in FIGS. 4 in the first embodiment and 7 in the second embodiment. By taking the characteristic expansion form described, the absorption rate is improved and the risk of lateral leakage is reduced. Since the characteristics of the intermediate sheet 30 and the characteristics of the intermediate sheet 30a have the effect of improving the absorption rate and reducing the risk of lateral leakage by themselves, the absorption rate and the prevention of lateral leakage are prevented by using the intermediate sheet 30b having these characteristics. The sex can be enhanced to each step.

[1-4. Fourth Embodiment]
FIG. 9 shows the intermediate sheet 30c used in the fourth embodiment of the laminated body of the present invention in the same format as in FIG. The laminated body of the third embodiment is the same as the laminated body 10 of the first embodiment described above, except that the intermediate sheet 30 is changed to the intermediate sheet 30c.

Further, the intermediate sheet 30c is a reversible specification having the same low density / convex region Al + and high density / concave region Bh- on both sides as the intermediate sheet 30b used in the third embodiment, and has a high density / concave region. The region Bh-is located inside the longitudinal end LE of the intermediate sheet 30c.

The method of providing the intermediate sheet 30c with a low-density and convex region and a high-density and concave region on both sides thereof is not particularly limited. Preferably, an embossing method is used in which the fabric of the intermediate sheet 30c is compressed in the thickness direction from both sides at a place where a region forming a high density and a recess is to be provided.

The laminated body of the fourth embodiment has the characteristics of the intermediate sheet 30 used in the first embodiment and the characteristics of the intermediate sheet 30a used in the second embodiment, similarly to the intermediate sheet 30b used in the third embodiment. Since the intermediate sheet 30b having both of the above is used, the absorption rate and the lateral leakage prevention property can be further improved as in the third embodiment.

[1-5. Fifth Embodiment]
In the laminated body of the present invention, as long as the region B is located inside the longitudinal end of the intermediate sheet, it does not matter whether the region B reaches the short end of the intermediate sheet. On the other hand, since the laminated body of the present invention has a configuration in which the absorption rate is improved by promoting the diffusion of the absorbed liquid in the in-plane direction, the risk of leakage from the short end is further reduced. Therefore, the region B may be located inside the short end SE of the intermediate sheet.

FIG. 10 schematically shows an external view of a part (a part including the short end) of the intermediate sheet used in the fifth embodiment of the laminated body of the present invention. The laminate of the fifth embodiment is the same as the laminate 10 of the first embodiment, except that the intermediate sheet 30 is changed to the intermediate sheet 30d.

In the intermediate sheet 30d used in the present embodiment, the high-density region Bh is located inside the short end SE. The fact that the high-density region Bh is located inside the short end SE means that there is no portion where the high-density region Bh reaches the short end SE of the intermediate sheet 30, and the entire high-density region Bh is the intermediate sheet. It means that it is arranged inward in the in-plane direction from both short end SEs of 30. That is, both short end SE portions of the intermediate sheet 30 are composed of the low density region Al.

As a result, when the liquid is absorbed, the water-absorbent resin layer expands so as to form a convex portion on the short end SE portion of the water-absorbent resin layer as well as the longitudinal end LE portion, thereby forming a physical barrier. Therefore, the risk of leakage from the short end SE (for example, rear leakage) is also reduced.

The fifth embodiment has been described with reference to the case where the region A is the same low-density region Al as the first embodiment and the region B is the same high-density region Bh as the first embodiment. In the fifth embodiment, the low density region Al is changed to the convex region A + in the second embodiment or the low density / convex region Al + in the third embodiment, and the high density region Bh is changed to the concave region B- in the second embodiment. Alternatively, it is also applied when the intermediate sheet changed to the high density / recessed region Bh- in the third embodiment is used. Further, the fifth embodiment is also applied to the case where the intermediate sheet having the cross-sectional shape described in the fourth embodiment is used.

[1-6. Modification example of area A and area B]
The shapes of the regions A and B are not limited to those shown in the first embodiment, and as long as they have a shape having a longitudinal direction, the liquid initially exposed as described with reference to FIG. It is considered that the convex portion 51A formed by the absorption of the above guides the liquid to be absorbed from the next time onward so as to spread in the in-plane direction of the laminated body 10', and the absorption rate can be improved. Further, as long as the region B is present inside the longitudinal end LE, the convex portion 51A formed by the absorption of the initially exposed liquid is lateral at the longitudinal end LE, as described with reference to FIG. It is thought to reduce the risk of leakage.

FIG. 11 schematically shows some examples of the shapes of regions A and B. In FIG. 11, a plan view of the intermediate sheet as viewed from the first sheet side is shown, the solid line represents the area B, and the blank portion other than the solid line represents the area A. As described above, as long as the region A has a shape having a longitudinal direction and the region B exists inside the longitudinal end LE, the absorption rate can be improved and the risk of lateral leakage can be reduced, which is shown in FIG. 11 (a). As described above, even if only two regions A are present at the longitudinal end LE, the laminate of the present invention can exhibit excellent absorption rate and lateral leakage prevention even when exposed to a plurality of liquids. In all the examples shown in FIG. 11, the region B is arranged inside the short end SE, but it is permissible that the region B reaches the short end SE.

It is preferable that the region A and the region B include a portion in which either or both of them form a streak portion from the viewpoint of improving the efficiency of guiding the absorbed liquid so as to spread in the in-plane direction. Examples of the region A having a portion forming a streak portion include FIGS. 11 (a), 11 (d), 11 (e), and 11 (f). Further, as an example in which the region B includes a portion forming a linear portion, FIGS. 11 (a) to 11 (f) can be mentioned.

When the region A includes a linear portion, it is preferable that the linear portion extends in the direction including the longitudinal LD of the intermediate sheet. The fact that the streak portion extends in the "direction including the longitudinal direction LD" means that the streak portion contains the longitudinal direction LD component regardless of whether or not the extending direction of the streak portion is parallel to the longitudinal direction LD. In other words, the "direction including the longitudinal LD" means an arbitrary direction other than the direction perpendicular to the longitudinal LD. That is, in all the examples of FIGS. 11 (a), 11 (d), 11 (e), and 11 (f), the streaks extend in the direction including the longitudinal LD of the intermediate sheet. .. In such an embodiment, when the liquid exposed from the second time onward moves in the in-plane direction of the laminated body, the movement in the longitudinal direction LD becomes more efficient, so that the shape of the laminated body is effectively used. It is preferable in that it can be done.

When the region A includes a linear portion, it is more preferable that the linear portion extends substantially parallel to the longitudinal LD of the intermediate sheet. The fact that the streaks extend substantially parallel to the longitudinal LD of the intermediate sheet means that the extending direction of the streaks may deviate by ± 5 ° with respect to the longitudinal LD. Examples of such an embodiment include FIGS. 11 (a) and 11 (e). In such an embodiment, when the absorbed liquid moves in the in-plane direction of the laminate, the movement in the longitudinal direction LD becomes particularly efficient, so that the shape of the laminate can be used more effectively, which is preferable. ..

When the area B includes a streak, it is preferable that the streak is arranged on the short center line M of the intermediate sheet. When the region B is composed of a plurality of streaks, at least one of the streaks may be arranged on the short center line M of the intermediate sheet. Examples of such an embodiment include FIGS. 11 (a) and 11 (e). In such an embodiment, when the absorbed liquid moves in the in-plane direction of the laminate, it can move at least to the place farthest from the longitudinal end LE, so that the lateral leakage prevention property can be more preferably obtained. Is preferable.

Regardless of their shapes, it is preferable that a plurality of regions A and B are alternately arranged in the lateral SD-A of those regions. Examples of such an embodiment include FIGS. 11 (c), 11 (d), 11 (e), and 11 (f). In such an embodiment, when the liquid is absorbed, a plurality of groove-shaped recesses 42 described in FIG. 4 are formed, so that the absorbed liquid is more efficiently transferred to the LD in the longitudinal direction, and the shape of the laminated body is formed. Is preferable in that it can be effectively used.

Further, it is more preferable that both the area A and the area B include the streaks, and a plurality of the streaks of the area A and the streaks of the area B are arranged in parallel. Examples of such an embodiment include FIGS. 11 (d), 11 (e) and 11 (f). In such an embodiment, the movement of the absorbed liquid in the longitudinal direction LD becomes more efficient, and the shape of the laminated body can be used more effectively.

The shapes of the region A and the region B shown in FIG. 11 may be applied individually, or may be applied in a state where two or more types of shapes are combined.

The width of the region A (that is, the width occupied by the region A in the lateral direction SD-A) is not particularly limited, and examples thereof include 0.3 to 5 cm. The width of the region A is preferably 0.4 to 3.5 cm, more preferably 0.6 to 3 cm, still more preferably, from the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property for several liquid exposures. Is 0.8 to 2.8 cm, more preferably 1 to 2.3 cm, and even more preferably 1.2 to 1.8 cm. The width of the region A may be generally constant or may vary within the above range in the extending direction.

The width of the region B is not particularly limited, but is preferably 1 to 15 mm, more preferably 2 to 12 mm, still more preferably 3 to, from the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property with respect to several liquid exposures. 10 mm, more preferably 3 to 8 mm is mentioned. The width of the region B may be generally constant or may vary within the above range in the extending direction.

The area ratio occupied by the region B in the intermediate sheet is not particularly limited, but the lower limit is preferably 3% or more, more preferably, from the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property against several liquid exposures. It is preferably 5% or more, more preferably 10% or more, still more preferably 15% or more, still more preferably 18% or more, and the upper limit thereof is preferably 50% or less, more preferably 40% or less, still more preferably. Is 30% or less, more preferably 25% or less, still more preferably 22% or less.

Note that the modification shown in FIG. 11 can be applied to all the above-described embodiments.

[2. Material and thickness of each component of the laminate]
The material and thickness of each component constituting the laminate of the present invention are not particularly limited, and the material and thickness capable of each component having the above-mentioned characteristics are appropriately selected. The following contents can be applied in common to all the above-described embodiments, except when a specific embodiment is particularly mentioned.

[2-1. 1st sheet]
The first sheet is not particularly limited as long as it is liquid permeable. The form of the first sheet is not particularly limited as long as it has a space or a hole communicating with each other in the thickness direction and the space or the hole has a size that does not allow the water-absorbent resin constituting the water-absorbent resin layer to pass through. Examples of the form of the first sheet include non-woven fabrics, woven fabrics and porous sheets. Among these forms, a non-woven fabric is preferable from the viewpoint of further improving the absorption rate for multiple liquid exposures and / or improving the side leakage prevention property, or in addition to reducing the amount of reversion. Can be mentioned.

The form of the non-woven fabric is not particularly limited, and examples thereof include air-through non-woven fabric, point-bonded non-woven fabric, spunbond non-woven fabric, spunlace non-woven fabric, thermal bond non-woven fabric, melt-blow non-woven fabric, and air-laid non-woven fabric. Among these non-woven fabrics, air-laid non-woven fabrics are preferable from the viewpoint of further improving the absorption rate for multiple liquid exposures and / or improving the side leakage prevention property, or in addition to reducing the amount of reversion. Can be mentioned.

The material of the first sheet includes polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT) and polyethylene naphthalate (PEN), and polyamides such as nylon. Examples include resins such as rayon. These resins may be used alone or in combination of two or more.

When the form of the first sheet is non-woven or woven cloth, the material of the first sheet includes cotton, silk, linen, and pulp (cellulose) in addition to the above-mentioned resin fibers (synthetic resin fibers). Natural fibers such as are also mentioned. These fibers may be used alone or in combination of two or more.

Among the above-mentioned materials, resin fibers are preferable from the viewpoint of further improving the absorption rate for multiple liquid exposures and / or improving the side leakage prevention property, or in addition to reducing the amount of reversion. And a combination with natural fibers, more preferably a combination of polyolefin fibers and pulp.

The basis weight of the first sheet is not particularly limited, but is preferably 20 to 60 g / m ² from the viewpoint of further improving the absorption rate for multiple liquid exposures or, in addition, reducing the amount of reversion. It is preferably 30 to 50 g / m ² , and more preferably 35 to 45 g / m ² .

The thickness of the first sheet is not particularly limited, but is preferably 0.1 to 0.8 mm from the viewpoint of further improving the absorption rate for multiple liquid exposures or, in addition, reducing the amount of reversion. It is more preferably 0.2 to 0.6 mm, further preferably 0.3 to 0.5 mm, and even more preferably 0.35 to 0.45 mm.

[2-2. Water-absorbent resin layer]
As the material of the water-absorbent resin layer (that is, the water-absorbent resin), a resin that can absorb water and has a property of swelling by absorbing water, that is, generally a highly water-absorbent resin (SAP). ) Is not particularly limited as long as it is called.

Specific examples of the water-absorbent resin include a hydrolyzate of a starch-acrylonitrile graft copolymer, a neutralized product of a starch-acrylic acid graft polymer, a saponified product of a vinyl acetate-acrylic acid ester copolymer, and an acrylic acid moiety. Examples thereof include crosslinked products of Japanese polymers and water-absorbent resins such as partially neutralized polyacrylic acid. These water-absorbent resins may be used alone or in combination of two or more.

Among these water-absorbent resins, a crosslinked product of a partially neutralized acrylic acid polymer is preferable from the viewpoint of further improving the absorption rate for multiple liquid exposures. The degree of neutralization of the crosslinked product of the partially neutralized acrylic acid polymer is, for example, 50 mol% or more, preferably 60 to 90 mol%, and more preferably 70 to 80 mol%. A method for synthesizing a crosslinked product of a partially neutralized acrylic acid polymer is known, and specific examples thereof include a reverse phase suspension polymerization method and an aqueous solution polymerization method.

The thickness of the water-absorbent resin layer is not particularly limited, but is, for example, 25 to 600 g, preferably 50 to 450 g / m ² , more preferably 25 to 600 g per 1 m ² of the laminated surface of the laminated body (that is, the surface perpendicular to the laminating direction LMD 10). Has a thickness of 100 to 400 g / m ² , more preferably 150 to 200 g / m ² .

The amount of physiological saline absorbed by the water-absorbent resin is not particularly limited, but is preferably 30 to 75 g / g, more preferably 40 to 73 g / g, from the viewpoint of absorbing a larger amount of liquid and preventing the gel blocking phenomenon. Further preferably, it is 50 to 70 g / g, more preferably 60 to 70 g / g, and particularly preferably 65 to 70 g / g.

The amount of the water-absorbent resin retained in the physiological saline solution is not particularly limited, but is preferably 20 to 60 g / g, more preferably 25, from the viewpoint of further enhancing the absorption rate and / or the side leakage prevention property against several liquid exposures. Examples thereof include ~ 58 g / g, more preferably 30 to 56 g / g, still more preferably 40 to 54 g / g, and even more preferably 48 to 52 g / g.

The physiological saline water absorption rate of the water-absorbent resin is not particularly limited, but is preferably 25 to 80 seconds, more preferably 30 to 30 seconds, from the viewpoint of further improving the absorption rate and / or the side leakage prevention property for several liquid exposures. 80 seconds, more preferably 40 to 80 seconds, still more preferably 44 to 80 seconds, still more preferably 47 to 80 seconds. Since the laminate of the present invention exhibits an excellent water absorption rate improving effect and lateral leakage prevention property against a plurality of liquid exposures, the water absorption resin itself is effectively excellent in water absorption even when the water absorption rate is relatively slow. It is possible to achieve a speed improving effect and a lateral leakage prevention property. From this point of view, preferable examples of the physiological saline water absorption rate of the water-absorbent resin include 25 to 70 seconds, preferably 25 to 60 seconds, and more preferably 25 to 50 seconds.

The medium particle size of the water-absorbent resin is not particularly limited, but is preferably 100 to 600 μm, more preferably 200 to 500 μm, from the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property against several liquid exposures. More preferably, it is 300 to 400 μm, and further preferably 350 to 370 μm.

[2-3. Intermediate sheet]
The material of the intermediate sheet is not particularly limited as long as it is liquid-absorbent. The form of the intermediate sheet is not particularly limited as long as it has at least a space, a hole, and / or a hole communicating with the water-absorbent resin layer side. Examples of intermediate sheets include non-woven fabrics, woven fabrics and porous sheets. Among these forms, a non-woven fabric is preferable from the viewpoint of further enhancing the absorption rate and / or the side leakage prevention property against several liquid exposures.

The form of the non-woven fabric is not particularly limited, and examples thereof include air-through non-woven fabric, point-bonded non-woven fabric, spunbond non-woven fabric, spunlace non-woven fabric, thermal bond non-woven fabric, melt-blow non-woven fabric, and air-laid non-woven fabric. Among these non-woven fabrics, an air-through non-woven fabric is preferable from the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property against several liquid exposures.

The texture of the intermediate sheet is not particularly limited, but the lower limit is preferably 20 g / m ² or more, more preferably 30 g, from the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property against several liquid exposures. / M ² or more, more preferably 40 g / m ² or more, still more preferably 43 g / m ² or more, and the upper limit thereof is preferably 60 g / m ² or less, more preferably 55 g / m ² or less, still more preferably. 50 g / m ² or less, more preferably 47 g / m ² or less.

The thickness t of the intermediate sheet is not particularly limited, and for example, 0.7 mm or more can be mentioned. From the viewpoint of further enhancing the absorption rate and / or the lateral leakage prevention property against several liquid exposures, the thickness t is preferably 1.5 mm or more, more preferably 2 mm or more, still more preferably 2.3 mm or more. Be done. The upper limit of the thickness t range of the intermediate sheet is not particularly limited, and examples thereof include 4 mm or less, preferably 3 mm or less, and more preferably 2.8 mm or less. The thickness t of the intermediate sheet is a portion corresponding to the region A when the region A has a convex portion and the region B has a concave portion as in the second to fourth embodiments. The thickness of.

[2-4. Other water-absorbent resin layer]
The material of the other water-absorbent resin layer is not particularly limited, but can be selected from the water-absorbent resins listed as the material of the above-mentioned water-absorbent resin layer. The water-absorbent resin used for the other water-absorbent resin layer may be the same as or different from the water-absorbent resin used for the above-mentioned water-absorbent resin layer.

The thickness of the other water-absorbent resin layer is not particularly limited, but can be selected from the values listed as the thickness of the water-absorbent resin layer described above. The thickness of the other water-absorbent resin layer and the thickness of the above-mentioned water-absorbent resin layer may be the same or different.

[2-3. 2nd sheet]
Examples of the second sheet include a liquid-permeable sheet and an impermeable sheet. The second sheet in the case of a liquid-permeable sheet is a sheet selected from those used as the first sheet, and does not have a predetermined high-wetting area and low-wetting area in the first sheet. A sheet having the same form and material as the first sheet can be mentioned.

When the second sheet is a sheet selected from those used as the first sheet, the first sheet and the second sheet may be the same or different.

[2-4. Adhesive layer]
The adhesive resin composition used for the adhesive layer is not limited as long as the water-absorbent resin and the intermediate sheet and / or the second sheet can be adhered to each other, and can be appropriately selected by those skilled in the art. Since the laminate of the present invention is used for absorbing an aqueous liquid, a preferred adhesive composition includes a hot melt adhesive composition that is stable against an aqueous solvent.

[3. Preparation of laminate]
The method for producing the laminate of the present invention is not particularly limited, but for example, it can be produced by the following method.

For example, a laminated material in which a water-absorbent resin layer and a first sheet are laminated on the surface of the intermediate sheet provided with regions A and B is produced, and another water-absorbent resin is further placed on the intermediate sheet side of the laminated material. A laminated body can be produced by laminating the layer and the second sheet and integrating all the layers.

Further, when the adhesive layer is interposed between the water-absorbent resin layer and the intermediate sheet and between the water-absorbent resin layer and the second sheet, the regions A and B of the intermediate sheet are provided. A laminated material in which an adhesive layer, a water-absorbent resin layer, and a first sheet are laminated in this order is produced on the surface of the laminated material, and another water-absorbent resin layer is laminated on the intermediate sheet side of the laminated material. Further, the second sheet in which the adhesive layer is laminated on the surface is laminated so that the adhesive layer faces the other water-absorbent resin layer, and all the layers are integrated to produce a laminated body. can.

As the first sheet and the second sheet, those having the same shape and the same size can be used, and as the intermediate sheet, ones one size smaller than the first sheet and the second sheet can be used. In this case, all layers can be used. After laminating, all the layers can be integrated by collectively joining the peripheral edges of the first sheet and the second sheet (for example, heat crimping or the like).

[4. Use of laminated body]
The above-mentioned laminate of the present invention functions as an absorber showing excellent absorption rate and lateral leakage prevention property even when exposed to a plurality of liquids. Therefore, since the laminate of the present invention is useful for an absorbent article, the present invention also provides an absorbent article containing the laminate.

The absorbent article is not particularly limited, but preferably includes an absorbent article that needs to absorb the liquid a plurality of times. The liquid may be any liquid containing water. More specific examples of absorbent articles include disposable diapers, urine pads, menstrual napkins, pet sheets, food drip sheets, water blocking materials for power cables, and the like.

The present invention will be described in detail below with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples.

(1) Synthesis of water-absorbent resin particles (highly water-absorbent resin; SAP) (1-1) Production Example 1: Synthesis of SAPa <polymerization reaction in the first stage>
A round-bottomed cylindrical separable flask with an inner diameter of 11 cm and a capacity of 2 L, equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirring blade having four inclined paddle blades with a blade diameter of 5 cm in two stages as a stirrer. Got ready. To this flask, take 293 g of n-heptane as a hydrocarbon dispersion medium, add 0.736 g of a maleic anhydride-modified ethylene-propylene copolymer (Mitsui Chemicals Co., Ltd., High Wax 1105A) as a polymer-based dispersant, and stir. The temperature was raised to 80 ° C. to dissolve the dispersant, and then the temperature was cooled to 50 ° C.

In a beaker with an internal volume of 300 mL, take 92.0 g (1.03 mol) of an 80.5 mass% acrylic acid aqueous solution as a water-soluble ethylenically unsaturated monomer and cool it from the outside to 20.9 mass%. After adding 147.7 g of an aqueous sodium hydroxide solution to neutralize 75 mol%, 0.092 g of hydroxylethyl cellulose (Sumitomo Seika Co., Ltd., HECAW-15F) as a thickener, as a water-soluble radical polymerization initiator. 0.0736 g (0.272 mmol) of potassium persulfate and 0.010 g (0.057 mmol) of ethylene glycol diglycidyl ether as an internal cross-linking agent were added and dissolved to prepare a first-stage monomer aqueous solution.

Then, the first-stage monomer aqueous solution prepared above was added to a separable flask, and after stirring for 10 minutes, 6.62 g of n-heptane was added to HLB3 sucrose stearate as a surfactant (steal acid ester of HLB3). Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370) Add a surfactant solution obtained by heating and dissolving 0.736 g, and stir the system with nitrogen at a stirring speed of 500 rpm. After the substitution, the flask was immersed in a water bath at 70 ° C. to raise the temperature, and the polymerization was carried out for 60 minutes to obtain a first-stage polymerization slurry solution.

<Second stage polymerization reaction>
In a beaker with an internal volume of 500 mL, take 128.8 g (1.44 mol) of an 80.5 mass% acrylic acid aqueous solution as a water-soluble ethylenically unsaturated monomer, and while cooling from the outside, 27 mass% sodium hydroxide. After 159.0 g of an aqueous solution was added dropwise to neutralize 75 mol%, 0.090 g (0.333 mmol) of potassium persulfate was used as a water-soluble radical polymerization initiator, and ethylene glycol diglycidyl ether was used as an internal cross-linking agent. 0116 g (0.067 mmol) was added and dissolved to prepare a second-stage monomer aqueous solution.

After cooling the inside of the separable flask system to 25 ° C. while stirring at a stirring speed of 1000 rpm, the entire amount of the monomer aqueous solution in the second stage is added to the polymerized slurry liquid in the first stage. After the addition, the inside of the system was replaced with nitrogen for 30 minutes, the flask was again immersed in a water bath at 70 ° C. to raise the temperature, and the polymerization reaction was carried out for 60 minutes to obtain a hydrogel-like polymer.

After the polymerization, 0.589 g of a 45% by mass diethylenetriamine-5 sodium acetate 5 sodium aqueous solution was added to the obtained hydrogel polymer under stirring. Then, the flask was immersed in an oil bath set at 125 ° C., and 257.2 g of water was extracted from the system while refluxing n-heptane by azeotropic distillation of n-heptane and water. Then, 4.42 g (0.507 mmol) of a 2% by mass ethylene glycol diglycidyl ether aqueous solution was added to the flask as a surface cross-linking agent, and the mixture was kept at 83 ° C. for 2 hours.

Then, n-heptane and water were heated in an oil bath at 125 ° C. to evaporate and dried to obtain a dried product of polymer particles. The polymer particles are passed through a sieve having an opening of 850 μm, and 0.2% by mass of amorphous silica (Oriental Silicas Corporation, Toxile NP-S) with respect to the mass of the polymer particles is mixed with the polymer particles. , 231.2 g of SAPa containing amorphous silica was obtained.

(1-2) Production Example 2: Synthesis of SAPb In the water-containing gel-like polymer after the second stage polymerization of Production Example 1, 257.2 g of water was extracted from the system by azeotropic distillation. The same operation as in Production Example 1 was carried out to obtain 231.2 g of SAPb.

(1-3) Production Example 3: Synthesis of SAPc <polymerization reaction in the first stage>
A round-bottomed cylindrical separable flask with an inner diameter of 11 cm and a capacity of 2 L, equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirring blade having four inclined paddle blades with a blade diameter of 5 cm in two stages as a stirrer. Got ready. To this flask, take 293 g of n-heptane as a hydrocarbon dispersion medium, add 0.736 g of a maleic anhydride-modified ethylene-propylene copolymer (Mitsui Chemicals Co., Ltd., High Wax 1105A) as a polymer-based dispersant, and stir. The temperature was raised to 80 ° C. to dissolve the dispersant, and then the temperature was cooled to 50 ° C.

Then, the first-stage monomer aqueous solution prepared above was added to a separable flask, and after stirring for 10 minutes, 6.62 g of n-heptane was added to HLB3 sucrose stearate as a surfactant (steal acid ester of HLB3). Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370) Add 0.736 g of a surfactant solution by heating and dissolve it, and set the rotation speed of the stirrer to 550 rpm to sufficiently stir the inside of the system with nitrogen. After the substitution, the flask was immersed in a water bath at 70 ° C. to raise the temperature, and the polymerization was carried out for 60 minutes to obtain a first-stage polymerization slurry solution.

After the polymerization, 0.265 g of a 45% by mass diethylenetriamine-5 sodium acetate 5 sodium aqueous solution was added to the obtained hydrogel polymer under stirring. Then, the flask was immersed in an oil bath set at 125 ° C., and 271.4 g of water was extracted from the system while refluxing n-heptane by azeotropic distillation of n-heptane and water. Then, 6.40 g (0.735 mmol) of a 2% by mass ethylene glycol diglycidyl ether aqueous solution was added to the flask as a surface cross-linking agent, and the mixture was kept at 83 ° C. for 2 hours.

Then, n-heptane and water were heated in an oil bath at 125 ° C. to evaporate and dried to obtain a dried product of polymer particles. The polymer particles are passed through a sieve having an opening of 850 μm, and 0.5% by mass of amorphous silica (Oriental Silicas Corporation, Toxile NP-S) with respect to the mass of the polymer particles is mixed with the polymer particles. , 230.6 g of SAPc containing amorphous silica was obtained.

(1-4) Production Example 4: Synthesis of SAPd <First-stage polymerization reaction>
A round-bottomed cylindrical separable flask with an inner diameter of 11 cm and a capacity of 2 L, equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirring blade having four inclined paddle blades with a blade diameter of 5 cm in two stages as a stirrer. Got ready. To this flask, take 293 g of n-heptane as a hydrocarbon dispersion medium, add 0.736 g of a maleic anhydride-modified ethylene-propylene copolymer (Mitsui Chemicals Co., Ltd., High Wax 1105A) as a polymer-based dispersant, and stir. The temperature was raised to 80 ° C. to dissolve the dispersant, and then the temperature was cooled to 50 ° C.

<Second stage polymerization reaction>
In a beaker with an internal volume of 500 mL, take 128.8 g (1.44 mol) of an 80.5 mass% acrylic acid aqueous solution as a water-soluble ethylenically unsaturated monomer, and while cooling from the outside, 27 mass% sodium hydroxide. After 159.0 g of an aqueous solution was added dropwise to neutralize 75 mol%, 0.103 g (0.381 mmol) of potassium persulfate was used as a water-soluble radical polymerization initiator, and ethylene glycol diglycidyl ether was used as an internal cross-linking agent. 0116 g (0.067 mmol) was added and dissolved to prepare a second-stage monomer aqueous solution.

After the polymerization, 0.589 g of a 45% by mass diethylenetriamine-5 sodium acetate 5 sodium aqueous solution was added to the obtained hydrogel polymer under stirring. Then, the flask was immersed in an oil bath set at 125 ° C., and 237.7 g of water was extracted from the system while refluxing n-heptane by azeotropic distillation of n-heptane and water. Then, 4.42 g (0.507 mmol) of a 2% by mass ethylene glycol diglycidyl ether aqueous solution was added to the flask as a surface cross-linking agent, and the mixture was kept at 83 ° C. for 2 hours.

Then, n-heptane and water were heated in an oil bath at 125 ° C. to evaporate and dried to obtain a dried product of polymer particles. The polymer particles are passed through a sieve having an opening of 850 μm, and 0.5% by mass of amorphous silica (Oriental Silicas Corporation, Toxile NP-S) with respect to the mass of the polymer particles is mixed with the polymer particles. , 226.0 g of SAPd containing amorphous silica was obtained.

(1-5) Production Example 5: Synthesis of SAP <First-stage polymerization reaction>
A round-bottomed cylindrical separable flask with an inner diameter of 11 cm and a capacity of 2 L, equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirring blade having four inclined paddle blades with a blade diameter of 5 cm in two stages as a stirrer. Got ready. To this flask, take 293 g of n-heptane as a hydrocarbon dispersion medium, add 0.736 g of a maleic anhydride-modified ethylene-propylene copolymer (Mitsui Chemicals Co., Ltd., High Wax 1105A) as a polymer-based dispersant, and stir. The temperature was raised to 80 ° C. to dissolve the dispersant, and then the temperature was cooled to 50 ° C.

In a beaker with an internal volume of 300 mL, take 92.0 g (1.03 mol) of an 80.5 mass% acrylic acid aqueous solution as a water-soluble ethylenically unsaturated monomer and cool it from the outside to 20.9 mass%. After adding 147.7 g of an aqueous sodium hydroxide solution to neutralize 75 mol%, 0.092 g of hydroxylethyl cellulose (Sumitomo Seika Co., Ltd., HECAW-15F) as a thickener, as a water-soluble radical polymerization initiator. 0.092 g (0.339 mmol) of 2,2'-azobis (2-amidinopropane) dihydrochloride, 0.018 g (0.067 mmol) of potassium persulfate, ethylene glycol diglycidyl ether 0 as an internal cross-linking agent .0046 g (0.026 mmol) was added and dissolved to prepare a first-stage monomer aqueous solution.

<Second stage polymerization reaction>
In a beaker with an internal volume of 500 mL, take 128.8 g (1.44 mol) of an 80.5 mass% acrylic acid aqueous solution as a water-soluble ethylenically unsaturated monomer, and while cooling from the outside, 27 mass% sodium hydroxide. After adding 159.0 g of the aqueous solution to neutralize 75 mol%, 0.129 g (0.476 mmol) of 2,2'-azobis (2-amidinopropane) dihydrochloride as a water-soluble radical polymerization initiator. And 0.026 g (0.096 mmol) of potassium persulfate and 0.0116 g (0.067 mmol) of ethylene glycol diglycidyl ether as an internal cross-linking agent were added and dissolved to prepare a second-stage monomer aqueous solution. ..

After the polymerization, 0.589 g of a 45% by mass diethylenetriamine-5 sodium acetate 5 sodium aqueous solution was added to the obtained hydrogel polymer under stirring. Then, the flask was immersed in an oil bath set at 125 ° C., and 201.4 g of water was extracted from the system while refluxing n-heptane by azeotropic distillation of n-heptane and water. Then, 4.42 g (0.507 mmol) of a 2% by mass ethylene glycol diglycidyl ether aqueous solution was added to the flask as a surface cross-linking agent, and the mixture was kept at 83 ° C. for 2 hours.

Then, n-heptane and water were heated in an oil bath at 125 ° C. to evaporate and dried to obtain a dried product of polymer particles. The polymer particles are passed through a sieve having an opening of 850 μm, and 0.2% by mass of amorphous silica (Oriental Silicas Corporation, Toxile NP-S) with respect to the mass of the polymer particles is mixed with the polymer particles. , 231.2 g of SAPe containing amorphous silica was obtained.

(1-6) Production Example 6: Synthesis of SAPf <polymerization reaction in the first stage>
A round-bottomed cylindrical separable flask with an inner diameter of 11 cm and a capacity of 2 L, equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirring blade having four inclined paddle blades with a blade diameter of 5 cm in two stages as a stirrer. Got ready. To this flask, take 293 g of n-heptane as a hydrocarbon dispersion medium, add 0.736 g of a maleic anhydride-modified ethylene-propylene copolymer (Mitsui Chemicals Co., Ltd., High Wax 1105A) as a polymer-based dispersant, and stir. The temperature was raised to 80 ° C. to dissolve the dispersant, and then the temperature was cooled to 50 ° C.

After the polymerization, 0.589 g of a 45% by mass diethylenetriamine-5 sodium acetate 5 sodium aqueous solution was added to the obtained hydrogel polymer under stirring. Then, the flask was immersed in an oil bath set at 125 ° C., and 234.2 g of water was extracted from the system while refluxing n-heptane by azeotropic distillation of n-heptane and water. Then, 4.42 g (0.507 mmol) of a 2% by mass ethylene glycol diglycidyl ether aqueous solution was added to the flask as a surface cross-linking agent, and the mixture was kept at 83 ° C. for 2 hours.

Then, n-heptane and water were heated in an oil bath at 125 ° C. to evaporate and dried to obtain a dried product of polymer particles. The polymer particles are passed through a sieve having an opening of 850 μm, and 0.2% by mass of amorphous silica (Oriental Silicas Corporation, Toxile NP-S) with respect to the mass of the polymer particles is mixed with the polymer particles. , 231.2 g of SAP f containing amorphous silica was obtained.

(2) Measurement of water-absorbent resin particles (2-1) Water absorption amount The water absorption amount was measured in a room adjusted to 25 ° C. ± 1 ° C. 500 g of physiological saline was weighed in a 500 mL beaker, and a stirrer bar (8 mmφ × 30 mm without ring) was put into the beaker. A beaker was placed on a magnetic stirrer and stirred at 600 r / min to disperse 2.0 g of water-absorbent resin particles so as not to generate mamaco. It was left in that state for 60 minutes to sufficiently swell the water-absorbent resin particles. Subsequently, the contents in the beaker were filtered using a standard sieve having a mesh size of 75 μm (mass Ma [g]). Excess water was filtered off from the swollen gel on the sieve by allowing the sieve to be tilted at an inclination angle of about 30 degrees with respect to the horizontal for 30 minutes. Then, the total mass Mb [g] of the sieve and the swollen gel on the sieve was measured, and the water absorption amount of the physiological saline of the water-absorbent resin particles was calculated from the following formula. The results are shown in Tables 1 and 2.
Water absorption [g / g] = (Mb-Ma) /2.0

(2-2) Water retention amount The water retention amount was measured in a room adjusted to 25 ° C ± 1 ° C. A cotton bag (Membrod No. 60, width 100 mm × length 200 mm) weighing 2.0 g of water-absorbent resin particles was placed in a beaker having an internal volume of 500 mL. After pouring 500 g of 0.9 mass% sodium chloride aqueous solution (physiological saline) into a cotton bag containing water-absorbent resin particles at once so that mamaco cannot be formed, tie the upper part of the cotton bag with a rubber ring and let it sit for 30 minutes. The water-absorbent resin particles were swollen by placing them. After 30 minutes, the cotton bag was dehydrated for 1 minute using a dehydrator (manufactured by Kokusan Co., Ltd., product number: H-122) set to have a centrifugal force of 167 G, and then contained the swollen gel after dehydration. The mass Wa [g] of the cotton bag was measured. The same operation was performed without adding the water-absorbent resin particles, the empty mass Wb [g] of the cotton bag when wet was measured, and the water retention amount of the physiological saline of the water-absorbent resin particles was calculated from the following formula. The results are shown in Tables 1 and 2.
Water retention [g / g] = (Wa-Wb) /2.0

(2-3) Water absorption rate The water absorption rate was measured in a room adjusted to 25 ° C ± 1 ° C. Weigh 50 ± 0.1 g of physiological saline into a 100 mL beaker, add a magnetic stirrer bar (8 mm φ × 30 mm without ring), immerse the beaker in a constant temperature water tank, and set the liquid temperature to 25 ± 0. The temperature was adjusted to 2 ° C. Next, a beaker is placed on a magnetic stirrer, a vortex is generated in a physiological saline solution at a rotation speed of 600 r / min, and then 2.0 ± 0.002 g of water-absorbent resin particles are quickly added to the beaker. Using a stopwatch, the time (seconds) from the addition of the water-absorbent resin to the time when the vortex on the liquid surface converges was measured and used as the water absorption rate of the water-absorbent resin particles. The results are shown in Tables 1 and 2.

(2-4) Medium particle size From the top, a JIS standard sieve with a mesh size of 600 μm, a mesh size of 500 μm, a mesh size of 425 μm, a mesh size of 300 μm, a mesh size of 250 μm, and a mesh size of 180 μm. Sieve, a sieve with an opening of 150 μm, and a saucer were combined in this order. 50 g of water-absorbent resin particles were placed in the combined top sieve and shaken for 10 minutes using a low-tap type shaker for classification. After classification, the mass of the particles remaining on each sieve was calculated as a mass percentage with respect to the total amount, and the particle size distribution was obtained. The relationship between the mesh size of the sieve and the integrated value of the mass percentage of the particles remaining on the sieve was plotted on a logarithmic probability paper by integrating the particles on the sieve in order from the one having the largest particle size with respect to this particle size distribution. By connecting the plots on the probability paper with a straight line, the particle size corresponding to the integrated mass percentage of 50% by mass was obtained as the medium particle size. The results are shown in Tables 1 and 2.

(3) Preparation of intermediate sheet The following non-woven fabric was prepared and cut into a shape having a longitudinal direction (rectangle of 10 cm × 40 cm).
・ Air-through non-woven fabric a (Guangzhou Jinhan Non-woven Fabric Co., Ltd., D45-200, basis weight 45 g / m ² )
・ Air-through non-woven fabric b (Jiangsu Hualong Non-woven Fabric Co., Ltd., basis weight 32 g / m ² )
・ Air-through non-woven fabric c (Jiangsu Hualong Non-woven Fabric Co., Ltd., basis weight 45 g / m ² )
・ Air-through non-woven fabric d (KNH Enterprise Co., Ltd., AT025-CP49-0, basis weight 25 g / m ² )
Air-laid non-woven fabric (KNH Enterprise Co., Ltd., 6190516-1A01, basis weight 40 g / m ² )
・ Spunlace non-woven fabric (Kuraray Co., Ltd., 70% rayon; 20% PET; 10% PP / PE, basis weight 35 g / m ² )

(3-1) Processing of Air-Through Nonwoven Fabric a The following processing was performed on the air-through nonwoven fabric a to obtain six types of nonwoven fabrics having different shapes of regions A and B.

(3-1-1)
A heat sealer (Fuji Impulse Co., Ltd., FI-450-5, time setting 3 to 5) is used for the air-through nonwoven fabric a, and the region Bh- is formed as an embossed portion (processed region) by the heat seal embossing method, and the residue is formed. Region (non-processed region) was defined as region Al +. Specifically, as shown in FIG. 12, the length of the nonwoven fabric is formed by forming four regions Bh- (embossed portions) having a width of about 5 mm in a direction parallel to the longitudinal direction of the nonwoven fabric at intervals of about 2 cm. A linear region Al + was obtained in a direction parallel to the direction. The obtained processed air-through nonwoven fabric a had the form of the intermediate sheet 30c shown in FIG.

(3-1-2)
By forming three strip regions Bh- (embossed portions) having a width of about 5 mm at intervals of about 3 cm, the strip region Al + was obtained in a direction parallel to the longitudinal direction of the nonwoven fabric, but (3). The same operation as in 1-1) was performed. The obtained processed air-through nonwoven fabric a had the form of the intermediate sheet 30c shown in FIG.

(3-1-3)
As shown in FIG. 13, by forming one region Bh- (embossed portion) of a streak having a width of about 5 mm on the short center line of the intermediate sheet, a region Al + is obtained in a direction parallel to the longitudinal direction of the nonwoven fabric. Except for the above, the same operation as in (3-1-1) was performed. The obtained processed air-through nonwoven fabric a had the form of the intermediate sheet 30c shown in FIG.

(3-1-4)
As shown in FIG. 14, by forming 12 streak regions Bh- (embossed portions) having a width of about 5 mm in a direction parallel to the lateral direction of the non-woven fabric at intervals of about 3 cm, the regions are parallel to the lateral direction of the non-woven fabric. A linear region Al + was obtained in the above direction. The obtained processed air-through nonwoven fabric a had the form of the intermediate sheet 30c shown in FIG.

(3-1-5)
As shown in FIG. 15, by forming 15 strip regions Bh- (embossed portions) having a width of about 5 mm at an angle of 45 ° with respect to the longitudinal direction of the nonwoven fabric at intervals of about 3 cm, in the longitudinal direction of the nonwoven fabric. On the other hand, a region of 45 ° striations Al + was obtained. The obtained processed air-through nonwoven fabric a had the form of the intermediate sheet 30c shown in FIG.

(3-1-6)
As shown in FIG. 16, three strips in the direction parallel to the longitudinal direction of the non-woven fabric and twelve in the direction parallel to the lateral direction, and a striation region Bh- (embossed portion) having a width of about 5 mm are arranged at intervals of about 3 cm. By doing so, a grid-like region Bh- was formed. The obtained processed air-through nonwoven fabric a had the form of the intermediate sheet 30c shown in FIG.

(3-2) Processing of air-through nonwoven fabric b The same processing as in (3-1-1) above was performed. The obtained processed air-through nonwoven fabric b had the form of the intermediate sheet 30c shown in FIG.

(3-3) Processing of air-through nonwoven fabric c The same processing as in (3-1-1) above was performed. The obtained processed air-through nonwoven fabric c had the form of the intermediate sheet 30c shown in FIG.

(3-4) Processing of air-through nonwoven fabric d The same processing as in (3-1-2) above was performed. The obtained processed air-through nonwoven fabric d had the form of the intermediate sheet 30c shown in FIG.

(3-5) Processing of air-laid nonwoven fabric The same processing as in (3-1-2) above was performed. The obtained processed air-laid nonwoven fabric had the form of the intermediate sheet 30c shown in FIG.

(3-6) Processing of spunlace non-woven fabric The same processing as in (3-1-2) above was performed. The obtained processed spunlace non-woven fabric had the form of the intermediate sheet 30c shown in FIG.

(4) Measurement of intermediate sheet The thickness of the area A (mm), the height of the area A (mm), the density of the area A (kg / m ³ ), and the density of the area A when the density of the area B is 1. The ratio and the area ratio (%) of the area B were measured. The results are shown in Tables 1 and 2.

(4-1) Thickness of region A The thickness of region A was measured by lightly sandwiching region A once in a thickness measuring instrument (Dial Thickness Gauge JB manufactured by Ozaki Seisakusho Co., Ltd.).

(4-2) Height of region A The thickness of region B is measured in the same manner as in (4-1), the difference from the thickness of region A is derived, and the value of half (1/2) of the difference is set. The height of the area A was set.

(4-3) Density of region A (kg / m ³ )
It was calculated by dividing the basis weight of the non-woven fabric of the intermediate sheet material by the thickness of the region A.

(5) Preparation of laminated body (5-1) Structure of laminated body First sheet, water-absorbent resin layer, adhesive layer, intermediate sheet, other water-absorbent resin layer, adhesive layer, and second sheet are in this order. A laminated body laminated with the above was produced.

(5-2) Material-Water-absorbent resin particles for the water-absorbent resin layer and other water-absorbent resin layers (Examples 1 to 13 and Comparative Examples 1 to 16)
・・ SAPa synthesized in Production Example 1
.. SAPb synthesized in Production Example 2
.. SAPc synthesized in Production Example 3
.. SAPd synthesized in Production Example 4
・・ SAPe synthesized in Production Example 5
.. SAPf synthesized in Production Example 6

Intermediate sheet (Examples 1 to 13 and comparative examples 7 to 9, 15)
・・ Processed air-through a non-woven fabric (longitudinal direction at 2 cm intervals)
・・ Processed air-through a non-woven fabric (longitudinal direction at 3 cm intervals)
・・ Processed air-through a non-woven fabric (1 piece in the longitudinal direction)
・・ Processed air-through a non-woven fabric (in the short direction)
・・ Processed air-through a non-woven fabric (diagonal 45 °)
・・ Processed air-through a non-woven fabric (lattice)
・・ Processed air-through b non-woven fabric (longitudinal direction)
・・ Processed air-through c non-woven fabric (longitudinal direction)
・・ Processed air-through d non-woven fabric (longitudinal direction)
・・ Processed air-laid non-woven fabric (longitudinal direction)
・・ Processed spunlace non-woven fabric (longitudinal direction)
-Intermediate sheet (Comparative Examples 1 to 6, 10 to 14, 16)
・・ Unprocessed air-through a non-woven fabric ・・ Unprocessed air-through b non-woven fabric ・・ Unprocessed air-through c non-woven fabric ・・ Unprocessed air-through d non-woven fabric ・・ Unprocessed air-laid non-woven fabric ・・ Unprocessed spunlace non-woven fabric

1st sheet and 2nd sheet (Examples 1 to 13 and Comparative Examples 1 to 16)
・・ Air-laid non-woven fabric (KNH Enterprise Co., Ltd., 6190516-1A01, basis weight 40 g / m ² )

・ Adhesive layer ・・ Hot melt adhesive (Henkel Japan Ltd. Softening point 96 ℃ TECHNOMELT DM5912)

(5-3) Fabrication method A first sheet and a second sheet (both of the same material) cut into 14 cm × 42 cm were prepared. Hot melt coating machine (Harry's Co., Ltd., pump: Marshal150, table: XA-DT, tank set temperature: 150 ° C, hose set temperature: 165 ° C, gun head set temperature: 170 ° C) on the intermediate sheet, the total amount is 0. Ten 2 g of hot melt adhesive was applied at intervals of 10 mm along the longitudinal direction of the intermediate sheets shown in Tables 1 and 2. The adhesive application pattern was a spiral stripe. After that, the intermediate sheet is placed so that the surface to which the adhesive is not applied is in contact with the second sheet, so that the base material for the second sheet is 2 cm each in the front and back (from the short end) and 1 cm each in the left and right (from the long end). It was placed so that it would be exposed. Further, using an air flow type mixing device (Padformer manufactured by Otec Co., Ltd.), a total of 7.2 g of SAP for the water-absorbent resin layer shown in Tables 1 and 2 is uniformly sprayed on the intermediate sheet to absorb water. The resin layer was laminated. Subsequently, the first sheet is placed from the water-absorbent resin layer side of the intermediate sheet, sandwiched from above and below with a release paper, and a laminating machine (Hashima Co., Ltd., Straight Liner Fasting Press, model HP-600LFS, 110 ° C., 0.1 MPa). ) Was pressed and laminated to remove the release paper, and a laminated material to which the first sheet, the water-absorbent resin layer and the intermediate sheet were adhered was obtained.

After the obtained laminated material is inverted in the vertical direction, the second sheet is gently peeled off from the intermediate sheet, and again using the air flow type mixing device, the intermediate sheet of the laminated material is shown in Tables 1 and 2. A total of 7.2 g of SAP for the other water-absorbent resin layer was uniformly sprayed, and the other water-absorbent resin layer was laminated. In the same manner as above, 10 hot melt adhesives (total amount 0.2 g) were applied to the surface of the peeled second sheet that was in contact with the intermediate sheet. After that, the second sheet is laminated so that the adhesive layer faces the other water-absorbent resin layer, the entire layer is sandwiched between the release papers, pressed by a laminating machine and laminated, the release paper is removed, and the desired lamination is performed. I got a body.

(6) Evaluation of laminated body (6-1) Test solution A test solution having the following composition was prepared.
-Ion-exchanged water: 9865.75 g
NaCl: 100.0 g
・ CaCl _{2.2H 2} _O : 3.0g
・ MgCl _{2.6H 2} _O : 6.0g
-Triton X-100 (1%): 25.0 g
-Edible blue No. 1 (for coloring): 0.25 g

(6-2) Penetration rate In a room with a temperature of 25 ± 2 ° C, the laminate is placed on a horizontal table, and an air-through non-woven fabric (Rengo Nonwoven Products Co., Ltd., material composition) is placed on the first sheet as a top sheet. : 50% PP and 50% PE, grain amount: 21 g / m ² ) was placed. Next, a liquid injection cylinder (cylinder with both ends open) having a capacity of 100 mL and having an inner diameter of 3 cm was placed in the center of the top sheet. Subsequently, 80 mL of the test solution adjusted to 25 ± 1 ° C. in advance was poured into the cylinder from the upper part in the vertical direction at once. Using a stopwatch, the absorption time from the start of charging until the test solution completely disappeared from the cylinder was measured. This operation was further performed twice (three times in total) at intervals of 30 minutes, and the total value of the absorption time of each time was obtained as the total permeation rate [seconds]. The smaller the total value of the permeation rate, the shorter the total time required for the absorption of the liquid exposed 1 to 3 times, so that it can be evaluated that the absorption rate is excellent for a plurality of liquid exposures. The results are shown in Tables 1 and 2.

As a score (total permeation time shortening score) for evaluating the effect of improving the absorption rate for a plurality of liquid exposures, the total value according to Examples 1 to 6 and the total value according to the corresponding Comparative Examples 1 to 6 are used. Difference; difference between Examples 7 to 9 and Comparative Examples 7 to 9 and the total value according to the corresponding Comparative Example 10; Difference between the total value according to Examples 10 to 13 and the corresponding total value according to the corresponding Comparative Examples 11 to 14. Difference from each total value; and the difference between each of the total values according to Comparative Example 15 and the total value according to the corresponding Comparative Example 16 is obtained, and each of the obtained differences is the total value according to the corresponding Comparative Example. Was converted into a relative quantity with 100%. The total penetration time reduction score [%] is an evaluation value indicating how much the total time required for absorption of the exposed liquid 1 to 3 times could be reduced with respect to the corresponding comparative example. If the score is a positive number, the absorption rate for a plurality of liquid exposures can be improved, and it can be evaluated that the larger the score, the higher the effect of improving the absorption rate for a plurality of liquid exposures. The results are shown in Tables 1 and 2.

(6-3) Reversion amount Using the laminate (with top sheet) used for measuring the permeation rate, the reversion amount was measured by the following procedure. After 60 minutes have passed since the third test solution was added, a 10 cm square filter paper whose mass (Wd (g)) had been measured in advance was placed near the test solution injection position on the top sheet, and the bottom surface was placed on it. A 10 cm × 10 cm weight with a mass of 5 kg was placed. After loading for 5 minutes, the mass of the filter paper (We (g)) was measured, and the increased mass was defined as the reversion amount (g). The results are shown in Tables 1 and 2.
Reversion amount (g) = We-Wd

(6-4) Diffusion distance The length of the laminate (with the top sheet) for which the measurement of the amount of reversion has been completed is inverted in the vertical direction, and the laminate infiltrated with the test solution from the direction opposite to the direction in which the test solution is poured. Spreading dimension in the direction (planar direction of the absorber in the absorbent article) (length of the region of the diffusion region of the test solution through which the short center line of the laminate passes. Unit: cm [In other words, the diffusion region of the test solution. The length of the short center line of the laminate above]) was measured. The longer the diffusion distance, the more efficient the movement of the absorbed liquid in the longitudinal direction when it moves in the in-plane direction, indicating that the shape of the laminated body can be effectively used. The results are shown in Tables 1 and 2.

10, 10a ... Laminated body 10', 10'a ... Laminated body in a state of absorbing liquid 20 ...

First sheet

30, 30a, 30b, 30c, 30d ... Intermediate sheet 40 ... Second sheet 51 ... Water-absorbent resin layer 51 '... Water-absorbent resin layer 52 in a state of absorbing water ... Another water-absorbent resin layer A ... Region A
Al ... Low density region A + ... Convex region Al + ... Low density / convex region LD-A ... Longitudinal direction B of region A ... Region B
Bh ... High-density region B -... Recessed region Bh- ... High-density / recessed region LMD10 ... Laminating direction of laminated body LD ... Longitudinal direction (of laminated body, first sheet, water-absorbent resin layer, intermediate sheet, second sheet) LE ... Longitudinal end SE ... Short end M ... Short center line

Claims

Includes a liquid-permeable first sheet, a liquid-absorbent intermediate sheet, and a second sheet having a shape having a longitudinal direction, and at least a water-absorbent resin layer interposed between the first sheet and the intermediate sheet. It ’s a laminated body,
The intermediate sheet includes a region A and a region B having a shape having a longitudinal direction.
A laminated body in which the region A and the region B satisfy at least one of the following relationships (1) and (2) and satisfy the following relationship (3).
(1) When the region A has a low density and the region B has a high density, and the density of the region B is 1, the ratio of the density of the region A is 0.45 or less.
(2) The region A is a convex portion that is convex toward the water-absorbent resin layer, and the region B is a concave portion, and the height of the convex portion is 0.25 mm or more.
(3) The region B is located inside the longitudinal end of the intermediate sheet.
The laminate according to claim 1, wherein the region A and the region B satisfy the relationship of the above (1) and the above (2).
The laminate according to claim 1 or 2, wherein the region A includes a linear portion extending in a direction including the longitudinal direction of the intermediate sheet.
The laminate according to any one of claims 1 to 3, wherein the region A includes a linear portion extending substantially parallel to the longitudinal direction of the intermediate sheet.
The laminated body according to claim 4, wherein the region B includes a streak portion arranged on the short center line of the intermediate sheet.
The laminate according to any one of claims 1 to 5, wherein a plurality of the regions A and the regions B are alternately arranged in the lateral direction of those regions.
The laminated body according to claim 6, which includes a plurality of linear portions in which the region A and the region B are arranged in parallel.
The laminate according to any one of claims 1 to 7, wherein the region B is located inside the short end of the intermediate sheet.
An absorbent article containing the laminate according to any one of claims 1 to 8.