阅读说明：本技术 吸收体 (Absorbent body ) 是由 合田裕树 木下章惠 木村明宽 出谷耕 丹下悟 请川一夫 于 2019-08-23 设计创作，主要内容包括：本发明的目的在于提供吸收性能较高且体液反复吸收性优异的吸收体。本发明提供吸收体(17),其具有上表面(34)和下表面(35)、互相正交的长度方向(L)、宽度方向(W)及厚度方向(T),并具有吸收芯(21)和设在吸收芯(21)的厚度方向(T)的上方和下方中的至少一方的芯包覆片(26),其中,吸收芯(21)含有高吸收性聚合物,芯包覆片(26)是吸水性纤维相互缠结而成的平坦的吸水性无纺布,吸水性无纺布具有：多个高密度部(32),其沿着长度方向(L)延伸,在宽度方向(W)上排列配置；以及多个低密度部(33),其沿着长度方向(L)延伸,分别配置在多个高密度部(32)中的相邻的高密度部(32)之间。(The purpose of the present invention is to provide an absorbent body having high absorption performance and excellent repeated absorption of body fluids. The invention provides an absorber (17), which has an upper surface (34) and a lower surface (35), a length direction (L), a width direction (W) and a thickness direction (T) which are mutually orthogonal, and is provided with an absorption core (21) and a core wrap sheet (26) which is arranged above and below the thickness direction (T) of the absorption core (21), wherein, the absorption core (21) contains a high-absorption polymer, the core wrap sheet (26) is a flat water-absorption non-woven fabric formed by mutually intertwining water-absorption fibers, and the water-absorption non-woven fabric comprises: a plurality of high-density sections (32) that extend in the longitudinal direction (L) and are arranged in a row in the width direction (W); and a plurality of low-density sections (33) that extend in the longitudinal direction (L) and are respectively disposed between adjacent high-density sections (32) of the plurality of high-density sections (32).)

1. An absorbent body having an upper surface and a lower surface, a longitudinal direction, a width direction and a thickness direction orthogonal to each other,

and has an absorbent core and a core wrap sheet provided at least one of above and below the absorbent core in the thickness direction, wherein,

the absorbent core contains a superabsorbent polymer,

the core wrap sheet is a flat water-absorbent nonwoven fabric formed by mutually intertwining water-absorbent fibers,

the water-absorbent nonwoven fabric has:

a plurality of high-density portions extending in the longitudinal direction and arranged in the width direction; and

and a plurality of low-density portions extending in the longitudinal direction and each disposed between adjacent ones of the plurality of high-density portions.

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

the absorbent core is a laminated absorbent core in which a 1 st absorbent core layer, an intermediate layer, and a 2 nd absorbent core layer are laminated in this order from the upper surface toward the lower surface, the 1 st absorbent core layer, the intermediate layer, and the 2 nd absorbent core layer.

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

the intermediate layer is a liquid-permeable nonwoven fabric having hydrophilicity and liquid permeability.

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

the liquid-permeable nonwoven fabric is a through-air nonwoven fabric made of thermoplastic synthetic fibers.

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

the absorbent body further includes a super absorbent polymer-nonexistent region extending in the longitudinal direction in the 2 nd absorbent core layer, and the super absorbent polymer is nonexistent in the thickness direction.

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

the core wrap sheet comprises:

a 1 st core wrap sheet portion located above a thickness direction center plane of the absorbent body; and

a 2 nd core wrap sheet portion located below a thickness direction center plane of the absorbent body,

the core wrap sheet interiorly surrounds the laminated absorbent core.

7. The absorbent body according to claim 6, wherein,

the 1 st core wrap sheet portion comprises:

a central sheet portion disposed in the vicinity of the center in the width direction; and

a pair of outer sheet portions disposed on both outer sides in the width direction,

the 1 st core wrap sheet portion includes a pair of overlapping portions where the central sheet portion overlaps with each of the pair of outer sheet portions in the thickness direction, the pair of overlapping portions extending in the longitudinal direction.

8. The absorbent body according to claim 7, wherein,

the absorbent body is divided into two widthwise end portions disposed at both widthwise ends and a widthwise intermediate portion sandwiched between the two widthwise end portions,

the pair of overlapping portions are disposed at both ends in the width direction.

9. The absorbent body according to claim 8, wherein,

the width-directional dimension of the 1 st absorbent core layer is smaller than the width-directional dimension of the 2 nd absorbent core layer,

the 1 st absorbent core layer is disposed in the width direction intermediate portion.

10. The absorbent according to any one of claims 7 to 9, wherein,

the high-density portions are disposed at both ends of the core wrap sheet in the width direction.

11. An absorbent body for an absorbent article, having a 1 st surface and a 2 nd surface, a mutually orthogonal longitudinal direction, a width direction and a thickness direction, and comprising a laminated absorbent core in which a 1 st absorbent core layer, an intermediate layer and a 2 nd absorbent core layer are laminated in this order from the 1 st surface toward the 2 nd surface, and a core wrap sheet, wherein,

said 1 st and said 2 nd absorbent core layers comprise a superabsorbent polymer,

the core wrap sheet includes a 1 st core wrap sheet portion located on the 1 st surface side of the thickness direction center surface of the absorbent body and a 2 nd core wrap sheet portion located on the 2 nd surface side of the thickness direction center surface of the absorbent body,

the 1 st core wrapping sheet part comprises a water-absorbent nonwoven fabric composed of water-absorbent fibers having a fiber length of 25mm or more entangled with each other,

the absorbent body has a joint portion where the intermediate layer and the 1 st core wrap sheet portion are joined,

the water-absorbent nonwoven fabric has an elongation in a wet tensile test which is larger than an elongation in a dry tensile test, and a tensile strength in the wet tensile test which is lower than a tensile strength in the dry tensile test,

the intermediate layer is a thermally fused nonwoven fabric in which a plurality of thermoplastic synthetic fibers are fused,

the elongation in the wet tensile test of the heat-welded nonwoven fabric is in the range of 90% to 110% of the elongation in the dry tensile test, and the tensile strength in the wet tensile test of the heat-welded nonwoven fabric is in the range of 90% to 110% of the tensile strength in the dry tensile test.

12. The absorbent body according to claim 11, wherein,

the water-absorbing fiber having a fiber length of 25mm or more is a regenerated cellulose fiber.

13. The absorbent body according to claim 11 or 12, wherein,

the water-absorbent nonwoven fabric is a spunlace nonwoven fabric.

14. The absorbent body according to claim 11 or 12, wherein,

the heat-fusion non-woven fabric is a hot-air non-woven fabric.

15. The absorbent body according to claim 11 or 12, wherein,

the water-absorbent nonwoven fabric has:

a plurality of high-density portions extending in the longitudinal direction and arranged in the width direction; and

and a plurality of low-density portions extending in the longitudinal direction and each disposed between adjacent ones of the plurality of high-density portions.

16. The absorbent body according to claim 11 or 12, wherein,

the absorbent body is divided into two widthwise end portions disposed at both widthwise ends and a widthwise intermediate portion sandwiched between the two widthwise end portions,

the absorbent body includes an intermediate joint portion at the widthwise intermediate portion, at which the intermediate layer is joined to at least one of the 1 st and 2 nd core wrap sheet portions.

17. The absorbent body according to claim 16, wherein,

one of the 1 st and 2 nd absorbent core layers in contact with the 1 st or 2 nd core wrap sheet portions constituting the intermediate bond has a superabsorbent polymer non-existing region where a superabsorbent polymer is not present in the thickness direction,

the intermediate joint portion overlaps with the superabsorbent polymer non-existing region in the thickness direction.

18. The absorbent body according to claim 17, wherein,

the high absorbent polymer non-existing region is disposed extending in the length direction.

19. The absorbent body according to claim 11 or 12, wherein,

the 1 st surface is a skin side surface, and the 2 nd surface is a clothing side surface.

20. The absorbent body according to claim 19, wherein,

the 1 st core wrap sheet portion includes a central sheet portion disposed in the vicinity of the center in the width direction and a pair of outer sheet portions disposed on both outer sides in the width direction,

the 1 st core wrap sheet portion includes a pair of overlapping portions where the central sheet portion overlaps with each of the pair of outer sheet portions in the thickness direction, the pair of overlapping portions extending in the longitudinal direction.

21. The absorbent body according to claim 20, wherein,

in each of the pair of overlapping portions, each of the pair of outer panel portions is disposed on the 1 st surface side of the central panel portion, and an edge portion of each of the pair of outer panel portions on the central panel portion side is spaced apart from the central panel portion.

22. The absorbent body according to claim 11 or 12, wherein,

the absorbent body is divided into two widthwise end portions disposed at both widthwise ends and a widthwise intermediate portion sandwiched between the two widthwise end portions,

the absorbent body includes the joining portion at each of both ends in the width direction.

23. The absorbent body according to claim 22, wherein,

the dimension in the width direction of the 1 st absorbent core layer is smaller than the dimension in the width direction of the 2 nd absorbent core layer.

24. The absorbent body according to claim 11 or 12, wherein,

the water-absorbent nonwoven fabric has an elongation of 30% or more in both a wet tensile test and a dry tensile test, and the 30% elongation tensile strength in the wet tensile test is 25% or less of the 30% elongation tensile strength in the dry tensile test.

Technical Field

The present invention relates to an absorbent body.

Background

Absorbent articles having an Absorbent body (also referred to as an SAP sheet) with a high proportion of Super Absorbent Polymer (SAP) are known.

For example, patent document 1 discloses an absorbent body having a structure in which the entire absorbent core is covered with an upper core wrap sheet and a lower core wrap sheet, and the upper core wrap sheet is a nonwoven fabric having an uneven structure in which the upper core wrap sheet has a convex shape toward the skin of a wearer.

For example, patent document 2 discloses an absorbent body having a structure in which an absorbent core layer containing a super absorbent polymer and a binder is sandwiched between nonwoven fabrics from above and below the absorbent core layer, wherein the absorbent core layer is divided into a 1 st absorbent core layer and a 2 nd absorbent core layer by a predetermined intermediate layer.

Disclosure of Invention

Problems to be solved by the invention

In an absorbent body having a high proportion of superabsorbent polymer, when the superabsorbent polymer absorbs body fluid and swells, if the volume of the region formed inside the core wrap sheet in which the superabsorbent polymer is wrapped is too small, swelling of the superabsorbent polymer is restricted, and the absorption performance of the superabsorbent polymer tends to be lowered.

Here, in the absorbent body described in patent document 1, the core wrap sheet is provided with an uneven region. Accordingly, the concave and convex regions extend corresponding to the swelling of the super absorbent polymer, so that the core wrap sheet can extend. Thus, the swelling of the super absorbent polymer is not easily restricted.

However, in the absorbent body described in patent document 1, since the core wrap sheet of the absorbent body has the uneven regions, gaps are likely to be generated between the uneven regions and the top sheet, and there is a possibility that the transfer of body fluid from the top sheet to the absorbent body is hindered. Therefore, when the core wrap sheet described in patent document 1 is used, there is a possibility that the absorption performance of the absorber is lowered.

In the absorbent body of patent document 1, although the liquid diffusibility in the longitudinal direction of the lower core wrap sheet is disclosed, the liquid diffusibility in the longitudinal direction of the upper core wrap sheet is not disclosed. Therefore, in the absorbent body using the core wrap sheet of patent document 1, there is room for improvement in the liquid diffusibility in the longitudinal direction. That is, there is room for improvement in the body fluid absorption performance in the case of repeated absorption of body fluid as follows: even when the bodily fluid is repeatedly discharged, the absorbent body can absorb a large amount of the discharged bodily fluid over a wide range up to the vicinity of both ends in the longitudinal direction.

Accordingly, the present invention has been made in view of the above-mentioned problem 1, and an object 1 thereof is to provide an absorbent body having high absorption performance and excellent repeated absorption of body fluid.

In an absorbent body having a high proportion of superabsorbent polymer, when the superabsorbent polymer absorbs body fluid and swells, if the volume of the region formed inside the core wrap sheet in which the superabsorbent polymer is wrapped is too small, swelling of the superabsorbent polymer is restricted, and absorption performance is reduced. However, in the absorbent body described in patent document 2, since the upper core wrap sheet and the lower core wrap sheet are not bonded to each other, even if the super absorbent polymer swells, the swelling is not easily restricted by the upper core wrap sheet and the lower core wrap sheet. Therefore, in this absorbent body, a decrease in the absorption performance of the super absorbent polymer can be suppressed. However, in this absorbent body, since both the upper core wrap sheet and the lower core wrap sheet are not bonded to the intermediate layer, the upper core wrap sheet and the lower core wrap sheet are separated from each other by swelling of the super absorbent polymer and the intermediate layer is not deformed by an external force, and the absorbent body may have difficulty in deformation under conditions of absorbing body fluid, that is, form retention property in the case of moisture.

Further, if both the upper core wrap sheet and the lower core wrap sheet are bonded to the intermediate layer in order to improve the shape retention properties in the wet state, the volume of the region formed inside the upper core wrap sheet and inside the lower core wrap sheet is limited, and therefore swelling of the super absorbent polymer is suppressed, and there is a possibility that the absorption performance of the super absorbent polymer is lowered.

In the absorbent body described in patent document 2, when both the upper core wrap sheet and the lower core wrap sheet are bonded to the intermediate layer, the intermediate layer may be pressed and crushed from both sides by the swollen superabsorbent polymer of the 1 st absorbent core layer and the superabsorbent polymer of the 2 nd absorbent core layer when the body fluid is repeatedly absorbed. In this case, the gaps between the fibers in the intermediate layer are reduced, and the liquid permeability is lowered, so that the body fluid may hardly reach the 2 nd absorbent core layer through the intermediate layer. That is, there is room for improvement in the body fluid absorption performance in the case of repeated absorption of body fluid, that is, the repeated absorbability of body fluid.

Accordingly, the present invention has been made in view of the above problem 2, and an object 2 thereof is to provide an absorbent body which is excellent in shape retention when wet, has high absorption performance of a super absorbent polymer, and is excellent in repeated absorption of body fluid.

Means for solving the problems

The present inventors have conducted intensive studies in view of the above-mentioned problem 1. As a result, they have found that the above-mentioned problem 1 can be solved by using an absorbent body described later, and the present invention has been completed; the absorbent body includes an absorbent core and a core wrap sheet, the core wrap sheet is a nonwoven fabric in which water-absorbent fibers are entangled with each other, and a plurality of high-density portions and a plurality of low-density portions extending in a longitudinal direction and arranged in a width direction are alternately arranged.

Specifically, the present invention provides an absorbent body having an upper surface and a lower surface, a longitudinal direction, a width direction and a thickness direction which are orthogonal to each other, and having an absorbent core and a core wrap sheet provided above and below the absorbent core in the thickness direction, wherein the absorbent core contains a super absorbent polymer, the core wrap sheet is a flat water-absorbent nonwoven fabric in which water-absorbent fibers are entangled with each other, and the water-absorbent nonwoven fabric has: a plurality of high-density portions extending along the longitudinal direction and arranged in the width direction; and a plurality of low-density portions extending in the longitudinal direction and disposed between adjacent ones of the plurality of high-density portions.

The present inventors have conducted intensive studies in view of the above problem 2. As a result, they have found that the above-mentioned problem 2 can be solved by using an absorbent body described later, and the present invention has been completed; the absorbent body comprises a core wrap sheet and a laminated absorbent core comprising an intermediate layer formed by heat-bonding a nonwoven fabric, wherein the core wrap sheet on at least one surface side comprises a water-absorbent nonwoven fabric comprising water-absorbent fibers having a predetermined fiber length entangled with each other, and at least a part of the intermediate layer and the core wrap sheet are bonded to each other, wherein the water-absorbent nonwoven fabric is more likely to stretch when wet than when dry, and the intermediate layer has the same elongation characteristics when wet and when dry.

Specifically, the present invention provides an absorbent body for an absorbent article, having a 1 st surface and a 2 nd surface, a longitudinal direction, a width direction and a thickness direction orthogonal to each other, comprising a laminated absorbent core in which a 1 st absorbent core layer, an intermediate layer and a 2 nd absorbent core layer are laminated in this order from the 1 st surface toward the 2 nd surface, and a core wrap sheet, wherein the 1 st absorbent core layer and the 2 nd absorbent core layer contain a high-absorbent polymer, the core wrap sheet comprises a 1 st core wrap sheet portion located on the 1 st surface side with respect to a thickness direction center surface of the absorbent body and a 2 nd core wrap sheet portion located on the 2 nd surface side with respect to the thickness direction center surface of the absorbent body, and the 1 st core wrap sheet portion comprises a nonwoven fabric, the absorbent nonwoven fabric comprises absorbent fibers having a fiber length of 25mm or more entangled with each other, the absorbent body has a joint portion where the intermediate layer and the 1 st core wrap sheet are joined together, the absorbent nonwoven fabric has an elongation in a wet tensile test that is larger than an elongation in a dry tensile test and a tensile strength in a wet tensile test that is lower than a tensile strength in a dry tensile test, the intermediate layer is a heat-welded nonwoven fabric in which a plurality of thermoplastic synthetic fibers are welded together, the elongation in the wet tensile test of the heat-welded nonwoven fabric is in a range of 90% to 110% of the elongation in the dry tensile test, and the tensile strength in the wet tensile test of the heat-welded nonwoven fabric is in a range of 90% to 110% of the tensile strength in the dry tensile test.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an absorbent body having high absorption performance and excellent repeated absorption of body fluid can be provided.

Further, according to the present invention, it is possible to provide an absorbent body which is excellent in shape retention when wet, has high absorption performance of a super absorbent polymer, and is excellent in repeated absorption of body fluid.

Drawings

Fig. 1 is a top developed view of a tape-fixed disposable diaper 1 including an absorber 17 according to an embodiment of the present invention.

FIG. 2 is a view taken along W in FIG. 1₁－W₁A cross-sectional view of the absorbent body 17 before absorption of the bodily fluid of the face.

FIG. 3 is a view taken along W in FIG. 1₁－W₁A cross-sectional view of the absorbent body 17 after absorption of the bodily fluid of the face.

Fig. 4 is an enlarged perspective view of the core wrap sheet 26 provided in the absorber 17 according to the embodiment of the present invention.

Description of the reference numerals

L, the length direction; w, width direction; C. a widthwise intermediate portion; E. two ends in the width direction; t, the thickness direction; tc, the thickness direction central plane; 1. a disposable diaper; 3. a topsheet; 5. a negative film; 7. a leakage preventing wall; 9. an elastic member; 15. a hook and loop fastener; 17. an absorbent body; 18. 1, an absorption core layer; 19. an intermediate layer; 20. a 2 nd absorbent core layer; 21. an absorbent core (laminated absorbent core); 22. a central sheet portion; 23. an outer sheet portion; 24. 1 st core clad sheet portion; 25. a 2 nd core wrap sheet portion; 26. a core cladding sheet; 27. an overlapping portion; 28. a region where superabsorbent polymer is absent; 29. a joint portion; 30. an intermediate joint portion; 31. an edge portion; 32. a high density section; 33. a low density section; 34. an upper surface (1 st surface); 35. lower surface (2 nd surface).

Detailed Description

Mode for the invention

The present invention relates to the following embodiments.

[ means 1 ]

(Structure)

A 1 st aspect of the present invention is an absorbent body having an upper surface and a lower surface, a longitudinal direction, a width direction, and a thickness direction orthogonal to each other, and including an absorbent core and a core wrap sheet provided above and below the absorbent core in the thickness direction, wherein the absorbent core contains a super absorbent polymer, the core wrap sheet is a flat water-absorbent nonwoven fabric in which water-absorbent fibers are entangled with each other, and the water-absorbent nonwoven fabric includes: a plurality of high-density portions extending along the longitudinal direction and arranged in the width direction; and a plurality of low-density portions extending in the longitudinal direction and respectively disposed between adjacent high-density portions of the plurality of high-density portions.

(Effect)

According to the first aspect of the present invention, a flat core wrap sheet in which water-absorbent fibers are entangled with each other is provided on at least one of the upper layer and the lower layer of the absorbent core. The core wrap sheet has a plurality of high-density portions of water-absorbent fibers and a plurality of low-density portions of water-absorbent fibers, which extend in the longitudinal direction.

Since the core wrap sheet is flat, a gap is not easily generated between the core wrap sheet and the top sheet in the absorbent article using the absorbent body. Therefore, the body fluid absorbed by the top sheet is easily transferred to the core-covering sheet and easily absorbed by the absorbent body.

In this case, since the core wrap sheet is a water-absorbent nonwoven fabric in which water-absorbent fibers are entangled, the fibers are entangled with each other loosely due to moisture when the core wrap sheet is wet, and the water-absorbent fibers themselves are also likely to stretch due to moisture. Therefore, by allowing the core wrap sheet to absorb body fluid, the core wrap sheet can be relatively easily stretched, and the ability to follow the swelling of the super absorbent polymer can be improved. Also, the core wrap sheet has a low-density portion that is prone to elongation when a load is applied. Therefore, even when the super absorbent polymer swells, the core wrap sheet can be easily stretched, and the following property to the swelling of the super absorbent polymer can be improved. This can improve the absorption performance of the super absorbent polymer and hence the absorbent.

The core wrap sheet has a high-density portion that facilitates diffusion of body fluid absorbed by the absorber in the longitudinal direction. Therefore, the absorbent body can absorb body fluid over a wide range up to the vicinity of both longitudinal end portions of the absorbent body, and thus the repeated absorbability in the case of repeated absorption of body fluid is excellent.

[ means 2 ]

(Structure)

According to the absorbent body of the above-described aspect 1, according to aspect 2 of the present invention, the absorbent core is a laminated absorbent core in which the 1 st absorbent core layer, the intermediate layer, and the 2 nd absorbent core layer are laminated in this order from the upper surface toward the lower surface.

(Effect)

According to the 2 nd aspect of the present invention, in the intermediate layer sandwiched between the 1 st absorbent core layer and the 2 nd absorbent core layer, the body fluid easily penetrates in the longitudinal direction and the width direction, and the contact area between the absorbent body and the body fluid can be increased, so that the body fluid repeat absorbability of the absorbent body is excellent.

[ means 3 ]

(Structure)

In the absorbent body according to the above aspect 2, according to the 3 rd aspect of the present invention, the intermediate layer is a liquid-permeable nonwoven fabric having hydrophilicity and liquid permeability.

(Effect)

According to the 3 rd aspect of the present invention, since the intermediate layer is a liquid-permeable nonwoven fabric having hydrophilicity and liquid permeability, even when the absorbent body absorbs water, liquid permeability can be ensured, and the absorbent body has excellent repeated absorption of body fluid.

[ 4 th mode ]

(Structure)

In the absorbent body according to the above-described aspect 3, according to the 4 th aspect of the present invention, the liquid-permeable nonwoven fabric is a through-air nonwoven fabric made of thermoplastic synthetic fibers.

(Effect)

In general, since a through-air nonwoven fabric made of thermoplastic synthetic fibers is bulky and has excellent cushioning properties, even when the 1 st and 2 nd absorbent core layers swell, the diffusion properties of body fluid in the intermediate layer are not easily impaired, and the repeated absorption properties of body fluid in the absorbent body are excellent.

[ means 5 ]

(Structure)

The absorbent body according to any one of the above 2 to 4, according to the 5 th aspect of the present invention, wherein the absorbent body further comprises a super absorbent polymer-free region in the 2 nd absorbent core layer, the super absorbent polymer-free region extending in the longitudinal direction, and the super absorbent polymer being absent in the thickness direction.

(Effect)

According to the 5 th aspect of the present invention, since the body fluid can be diffused in the longitudinal direction through the region where the super absorbent polymer does not exist, the diffused body fluid easily permeates into the absorbent body, and the body fluid repeated absorbability of the absorbent body is excellent.

[ 6 th mode ]

(Structure)

In the absorbent body according to any one of the above aspects 2 to 5, according to aspect 6 of the present invention, the core wrap sheet includes: a 1 st core wrap sheet portion located above a thickness direction center plane of the absorber; and a 2 nd core wrap sheet portion located below the thickness direction center plane of the absorber, the core wrap sheet enclosing the laminated absorbent core.

(Effect)

According to the 6 th aspect of the present invention, the core wrap sheet formed by entangling the water-absorbent fibers with each other covers the entire absorbent core. Therefore, the high-density portion can diffuse the body fluid over a wide range in the longitudinal direction, and therefore the absorbent body is excellent in repeated absorption of the body fluid. Further, even in the case where the super absorbent polymer swells, the absorption performance of the super absorbent polymer is increased by the elongation of the low density portion.

[ 7 th mode ]

(Structure)

According to the absorbent body of the above 6, according to the 7 th aspect of the present invention, the 1 st core wrap sheet portion includes: a central sheet portion disposed in the vicinity of the center in the width direction; and a pair of outer sheet portions disposed on both outer sides in the width direction, wherein the 1 st core wrap sheet portion includes a pair of overlapping portions where the center sheet portion and each of the pair of outer sheet portions overlap in the thickness direction, and the pair of overlapping portions extend in the longitudinal direction.

(Effect)

According to the 7 th aspect of the present invention, the 1 st core wrap sheet has a pair of overlapping portions where the center sheet portion and the pair of outer sheet portions overlap in the thickness direction. Therefore, when a body pressure is applied, the fiber density of the water-absorbent fibers in the pair of overlapping portions tends to be higher than the fiber density of the absorbent fibers other than the pair of overlapping portions, and the body fluid is more likely to diffuse in the longitudinal direction in the pair of overlapping portions. This provides the absorbent body with excellent repeated diffusion of body fluid.

[ 8 th mode ]

(Structure)

In the absorbent body according to the 7 th aspect of the present invention, according to the 8 th aspect of the present invention, the 1 st absorbent core layer has a dimension in the width direction smaller than a dimension in the width direction of the 2 nd absorbent core layer, and the 1 st absorbent core layer is disposed in the width direction intermediate portion.

(Effect)

According to the 8 th aspect of the present invention, the 1 st absorbent core layer has a width dimension smaller than the width dimension of the 2 nd absorbent core layer, and the 1 st absorbent core layer is disposed in the width-direction intermediate portion of the absorbent body. Therefore, even when the body fluid is hardly absorbed by the 1 st absorbent core layer, the body fluid can reach the surface of the 2 nd absorbent core layer having a wide width on the surface of the 1 st absorbent core layer in the width direction. That is, the body fluid that is not absorbed by the 1 st absorbent core layer can be absorbed by the 2 nd absorbent core layer. This enables the absorbent body to be used more effectively, and the absorbent body has excellent repeated absorption of body fluid.

[ means 9 ]

(Structure)

According to the absorbent body of the 8 th aspect of the present invention, in the 9 th aspect of the present invention, the absorbent body is divided into both width direction end portions disposed at both ends in the width direction and a width direction intermediate portion sandwiched between both width direction end portions, and the pair of overlapping portions are disposed at both width direction end portions.

(Effect)

According to the 9 th aspect of the present invention, the pair of overlapping portions are provided at both widthwise end portions of the absorbent body. Therefore, the super absorbent polymer originating in the 1 st absorbent core layer is not present in the pair of overlapped portions, and thus the body fluid easily spreads in the longitudinal direction in the pair of overlapped portions while penetrating into the 2 nd absorbent core layer. This provides the absorbent body with excellent repeated absorption of body fluid.

[ 10 th mode ]

(Structure)

In the absorbent body according to any one of the above 7 to 9, according to a 10 th aspect of the present invention, the high-density portions are disposed at both ends of the core-covering sheet in the width direction.

(Effect)

According to the 10 th aspect of the present invention, since the high-density portions having high liquid permeability along the longitudinal direction are disposed at both ends of the core wrap sheet in the width direction, the fiber density of the water-absorbent fibers in the pair of superposed portions becomes higher, the liquid diffusibility in the pair of superposed portions can be further improved, and the body fluid repeated absorbability of the absorbent body can be improved.

[ 11 th mode ]

(Structure)

An 11 th aspect of the present invention is an absorbent body for an absorbent article, having a 1 st surface and a 2 nd surface, a longitudinal direction, a width direction and a thickness direction orthogonal to each other, and having a laminated absorbent core in which a 1 st absorbent core layer, an intermediate layer and a 2 nd absorbent core layer are laminated in this order from the 1 st surface toward the 2 nd surface, and a core wrap sheet, wherein the 1 st absorbent core layer and the 2 nd absorbent core layer contain a high-absorbent polymer, the core wrap sheet contains a 1 st core wrap sheet portion located on the 1 st surface side with respect to a thickness direction center surface of the absorbent body and a 2 nd core wrap sheet portion located on the 2 nd surface side with respect to the thickness direction center surface of the absorbent body, and the 1 st nonwoven core wrap sheet portion has water-absorbing properties, the absorbent nonwoven fabric comprises absorbent fibers having a fiber length of 25mm or more entangled with each other, the absorbent body has a joint portion where the intermediate layer and the 1 st core wrap sheet are joined together, the absorbent nonwoven fabric has an elongation in a wet tensile test that is larger than an elongation in a dry tensile test and a tensile strength in a wet tensile test that is lower than a tensile strength in a dry tensile test, the intermediate layer is a heat-welded nonwoven fabric in which a plurality of thermoplastic synthetic fibers are welded together, the elongation in the wet tensile test of the heat-welded nonwoven fabric is in a range of 90% to 110% of the elongation in the dry tensile test, and the tensile strength in the wet tensile test of the heat-welded nonwoven fabric is in a range of 90% to 110% of the tensile strength in the dry tensile test.

(Effect)

The intermediate layer provided in the absorbent body according to claim 11 of the present invention is composed of a nonwoven fabric in which a plurality of thermoplastic synthetic fibers are welded together and the elongation in a wet tensile test is in the range of 90% to 110% of the elongation in a dry tensile test, and the tensile strength in a wet tensile test is in the range of 90% to 110% of the tensile strength in a dry tensile test, and the intermediate layer has little change in elongation characteristics even when water is absorbed. Here, in the 11 th aspect of the present invention, the 1 st core wrap sheet portion is joined to the intermediate layer. Therefore, even if the 1 st core wrap sheet portion elongates (deforms) due to the superabsorbent polymer absorbing water and swelling, the deformation of the entire absorbent body can be suppressed by the intermediate layer that is less likely to elongate (deform). This makes the absorbent body excellent in shape retention in the wet state, i.e., in shape retention in the wet state.

Further, since the intermediate layer is formed by fusing thermoplastic fibers to each other, the characteristics with respect to the load are not easily changed at the time of drying and at the time of wetting, and therefore the intermediate layer is not easily elongated at the time of wetting, and the intermediate layer is not easily crushed even when the load is applied, for example, when the load is applied by the water absorption and expansion of the super absorbent polymers of the 1 st and 2 nd absorbent core layers. Therefore, even under the condition that the super absorbent polymer swells, the absorbent body has excellent liquid permeability as the permeability of body fluid in the intermediate layer, and the diffusibility of body fluid is not easily impaired, so that the absorbent body has excellent repeated absorption of body fluid by repeatedly absorbing body fluid.

In addition, at least the 1 st core wrap sheet portion of the core wrap sheet included in the absorbent body according to the 11 th aspect of the present invention includes a water-absorbent nonwoven fabric composed of water-absorbent fibers including water-absorbent fibers having a fiber length of 25mm or more entangled with each other, and the elongation in the wet tensile test is larger than the elongation in the dry tensile test, and the tensile strength in the wet tensile test is lower than the tensile strength in the dry tensile test. The 1 st core wrap sheet portion made of a water-absorbent nonwoven fabric has a property of being easily stretched when it absorbs moisture of body fluid, and when the 1 st surface is a skin side surface, the 1 st core wrap sheet portion absorbs body fluid that has permeated from the 1 st surface side when the absorbent body absorbs water, and is relatively easily stretched. In the case where the 1 st surface is a garment side surface, the 1 st core wrap sheet portion absorbs body fluid that has passed through the absorbent body and is held on the garment side surface of the absorbent body when the absorbent body absorbs water, and is relatively easily stretched. Thus, the absorption performance of the super absorbent polymer can be improved by the partial elongation of the 1 st core wrap sheet.

[ 12 th mode ]

(Structure)

According to the absorbent body of the 11 th aspect of the present invention, in the 12 th aspect of the present invention, the water-absorbent fibers having a fiber length of 25mm or more are regenerated cellulose fibers.

(Effect)

The regenerated cellulose fibers are superior to pulp fibers in fiber uniformity (fiber length, fiber diameter, etc.). Therefore, when the water-absorbent fiber having a fiber length of 25mm or more is a regenerated cellulose fiber, the water-absorbent nonwoven fabric is more likely to be elongated by water absorption and the absorption performance of the super-absorbent polymer is improved as compared with the case of pulp fiber, and on the other hand, when the water-absorbent nonwoven fabric is intended to be elongated at an elongation of a certain ratio or more, a relatively large tensile strength acts, and therefore the above-mentioned shape retention property in the wet state of the absorbent body is excellent.

[ 13 th mode ]

(Structure)

According to the absorbent body of the 11 th or 12 th aspect of the present invention, in the 12 th aspect of the present invention, the water-absorbent nonwoven fabric is a spunlace nonwoven fabric.

(Effect)

According to the 13 th aspect of the present invention, since the water-absorbent nonwoven fabric is a spunlace nonwoven fabric in which entanglement between fibers is likely to occur, the water-absorbent nonwoven fabric is likely to stretch, and the absorbency of the super-absorbent polymer is increased.

[ 14 th mode ]

(Structure)

An absorbent body according to any one of the above 11 to 13, wherein the heat-fusible nonwoven fabric is a hot-air nonwoven fabric according to claim 14 of the present invention.

(Effect)

Since the through-air nonwoven fabric is bulky and has excellent cushioning properties, even when the 1 st and 2 nd absorbent core layers swell, the liquid permeability of the intermediate layer is not easily impaired, and the repeated absorption of body fluid by the absorbent body is excellent.

[ 15 th mode ]

(Structure)

An 15 th aspect of the present invention is the absorbent body according to any one of the 11 th to 14 th aspects, wherein the water-absorbent nonwoven fabric includes: a plurality of high-density portions extending along the longitudinal direction and arranged in the width direction; and a plurality of low-density portions extending in the longitudinal direction and respectively disposed between adjacent high-density portions of the plurality of high-density portions.

(Effect)

According to the 15 th aspect of the present invention, the water-absorbent nonwoven fabric has high-density portions and low-density portions alternately arranged along the longitudinal direction. The plurality of high-density portions facilitate diffusion of body fluid in the longitudinal direction, and the plurality of low-density portions enable the water-absorbent nonwoven fabric to be easily stretched in the width direction of the absorbent body. Here, when the 1 st surface is a skin side surface, the 1 st core wrap sheet portion absorbs body fluid that has permeated from the 1 st surface side, and easily diffuses the body fluid in the longitudinal direction. In the case where the 1 st surface is a garment side surface, the 1 st core wrap sheet portion absorbs body fluid that has passed through the absorbent body and is held on the garment side surface of the absorbent body when the absorbent body absorbs water, and the body fluid is easily diffused in the longitudinal direction. As a result, the absorbent body can easily absorb body fluid over a wide range along the longitudinal direction thereof, and the absorption area ratio of the absorbent body is increased, and as a result, the absorbent body has excellent repeated absorption of body fluid.

[ 16 th mode ]

(Structure)

An absorbent body according to any one of the above 11 to 15, according to a 16 th aspect of the present invention, the absorbent body is divided into both widthwise end portions disposed at both widthwise ends and a widthwise intermediate portion sandwiched between the both widthwise end portions, and the absorbent body includes an intermediate joint portion in the widthwise intermediate portion, the intermediate layer being joined to at least one of the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion.

(Effect)

According to the 16 th aspect of the present invention, since the absorbent body has the intermediate joint section in which at least one of the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion is joined to the intermediate layer which is less likely to stretch when dry and when wet, the absorbent body is excellent in shape retention when dry and shape retention when wet.

[ 17 th mode ]

(Structure)

According to the absorbent body of the above 16, according to the 17 th aspect of the present invention, one of the 1 st and 2 nd absorbent core layers which is in contact with the 1 st or 2 nd core wrap sheet portion constituting the intermediate bond portion has a high-absorbent polymer nonexistence region where a high-absorbent polymer is nonexistence in the thickness direction, and the intermediate bond portion overlaps with the high-absorbent polymer nonexistence region in the thickness direction.

(Effect)

In the 17 th aspect of the present invention, since the region where the super absorbent polymer does not exist exists is present in the 1 st or 2 nd absorbent core layer in contact with the 1 st or 2 nd core wrap sheet portion constituting the intermediate joint portion, even when the super absorbent polymer swells, the body fluid penetrates into the absorbent body through the region where the super absorbent polymer does not exist, and therefore the body fluid repeat absorbability of the absorbent body is excellent. Further, since the intermediate bonded portion overlaps the superabsorbent polymer nonexistent region in the thickness direction, the intermediate bonded portion maintains the bonded structure even when the superabsorbent polymer swells, and the absorbent body has excellent shape retention properties in the wet state.

[ 18 th mode ]

(Structure)

According to the absorbent body of the 17 th aspect, the 18 th aspect of the present invention is the one in which the superabsorbent polymer nonexistence region extends in the longitudinal direction.

(Effect)

According to the 18 th aspect of the present invention, since the body fluid is diffused in the longitudinal direction by the superabsorbent polymer non-existing region, the absorbent area ratio of the absorbent body is high, and the body fluid repeated absorbency is excellent.

[ 19 th mode ]

(Structure)

According to the absorbent body of any one of the above 11 to 18, in the 19 th aspect of the present invention, the 1 st surface is a skin side surface, and the 2 nd surface is a garment side surface.

(Effect)

According to the 19 th aspect of the present invention, since the 1 st core wrap sheet portion having the water-absorbent nonwoven fabric is disposed on the skin side surface side, a part of the body fluid penetrates the water-absorbent nonwoven fabric and penetrates the water-absorbent nonwoven fabric before the body fluid is absorbed by the absorbent body, and the 1 st core wrap sheet portion is more likely to stretch when the body fluid is absorbed.

[ 20 th mode ]

(Structure)

According to the absorbent body of the 19 th aspect, the 20 th aspect of the present invention is the 1 st core wrap sheet portion including a central sheet portion disposed in the vicinity of the center in the width direction and a pair of outer sheet portions disposed on both outer sides in the width direction, the 1 st core wrap sheet portion including a pair of overlapping portions where the central sheet portion and each of the pair of outer sheet portions overlap in the thickness direction, the pair of overlapping portions extending in the longitudinal direction.

(Effect)

According to the 20 th aspect of the present invention, since the 1 st core wrap sheet portion has a pair of overlapping portions extending in the longitudinal direction, and the fiber density of the pair of overlapping portions is high, the absorption area ratio of the absorbent body is high, and the repeated absorption of body fluid is excellent.

[ 21 st mode ]

(Structure)

According to the absorbent body of the above 20 aspect, according to the 21 st aspect of the present invention, in each of the pair of overlapping portions, each of the pair of outer sheet portions is disposed on the 1 st surface side of the central sheet portion, and the edge portion of each of the pair of outer sheet portions on the central sheet portion side is separated from the central sheet portion.

(Effect)

According to the 21 st aspect of the present invention, when the intermediate portion in the width direction of the laminated absorbent core absorbs bodily fluids and swells, the edge portion of the outer sheet portion overlapping the central sheet portion floats from the surface of the central sheet portion due to the inclination of the upper surface of the absorbent body, and is in an upright state. This enables the edge portion of the outer sheet portion to function as a leakage preventing wall.

[ 22 th mode ]

(Structure)

An absorbent body according to any one of the above 11 to 21, wherein the absorbent body is divided into two widthwise end portions disposed at both widthwise ends and a widthwise intermediate portion sandwiched between the two widthwise end portions, and the absorbent body includes the joining portion at each of the two widthwise end portions.

(Effect)

According to the 22 nd aspect of the present invention, since the joining portions are located at each of the widthwise both end portions of the absorbent body, the intermediate layer supports the 1 st core wrap sheet portion at the widthwise both end portions when the absorbent body absorbs water, and the absorbent body is excellent in shape retention when wet.

[ means 23 ]

(Structure)

According to the absorbent body of the above 22, according to the 23 rd aspect of the present invention, the dimension in the width direction of the 1 st absorbent core layer is smaller than the dimension in the width direction of the 2 nd absorbent core layer.

(Effect)

According to the 23 rd aspect of the present invention, since the superabsorbent polymer derived from the 1 st absorbent core layer is not present in the region where the joint is located, the mechanical strength of the joint is less likely to be impaired by swelling accompanying water absorption of the superabsorbent polymer, and the absorbent body is excellent in shape retention under wet conditions.

[ 24 th mode ]

(Structure)

According to the absorbent body of any one of the above 11 to 23, in the 24 th aspect of the present invention, the core wrap sheet has an elongation of 30% or more in both a wet tensile test and a dry tensile test, and the 30% elongation tensile strength in the wet tensile test is 25% or less of the 30% elongation tensile strength in the dry tensile test.

(Effect)

According to the 24 th aspect of the present invention, since the 30% elongation tensile strength of the core wrap sheet in the wet tensile test is smaller than the 30% elongation tensile strength in the dry tensile test, the core wrap sheet easily follows the swelling of the super absorbent polymer, and the absorption performance of the super absorbent polymer is improved. Further, the tensile strength at 30% elongation of the core wrap sheet in the dry tensile test is greater than the tensile strength at 30% elongation in the wet tensile test, and therefore the shape retention property is excellent in dry.

(embodiment 1)

Hereinafter, embodiment 1 for solving problem 1 of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a top developed view of a tape-fixed disposable diaper 1 (hereinafter, also simply referred to as "disposable diaper") including an absorber 17 of the present embodiment, and fig. 2 is a view taken along W in fig. 1₁－W₁FIG. 3 is a cross-sectional view of the front absorbent body 17 before absorption of body fluid, taken along line W in FIG. 1₁－W₁A sectional view of the front absorbent body 17 after absorption of body fluid. As shown in fig. 1 and 2, the absorbent body 17 of the present embodiment has an upper surface 34 and a lower surface 35, has a longitudinal direction L, a width direction W, and a thickness direction T that are orthogonal to each other, and is divided into two width-direction end portions E and a width-direction intermediate portion C along the width direction W. Here, the width direction middle portion C is a region extending to about 70% of the width direction W centering on the center point of the width direction W of the portion having the largest dimension in the width direction W, and regions of about 15% of each of the left and right sides on both outer sides thereof are defined as both width direction end portions E. The longitudinal direction L of the disposable diaper 1 coincides with the longitudinal direction L of the absorbent member 17, and the width direction W of the disposable diaper 1 coincides with the length direction L of the absorbent member 17The width direction W coincides, and the thickness direction T of the disposable diaper 1 coincides with the thickness direction T of the absorbent body 17. The "absorbent article" of the present invention is not limited to a tape-fixed disposable diaper, and may be, for example, a pants-type disposable diaper, a urine pad, a light incontinence pad, a sanitary pad, a panty liner, or the like.

As shown in fig. 1, the disposable diaper 1 includes a liquid-permeable top sheet 3, a liquid-impermeable back sheet 5, an absorbent body 17 of the present embodiment disposed between the top sheet 3 and the back sheet 5, and further includes a leakage preventing wall 7 having an elastic member 9, a fastening tape 15, and the like. In the present embodiment, the absorber 17 is disposed between the top sheet 3 and the back sheet 5 such that the upper surface 34 is positioned on the top sheet 3 side of the disposable diaper 1 and the lower surface 35 is positioned on the back sheet 5 side of the disposable diaper 1, but in the present invention, the upper surface of the absorber may be disposed on the back sheet side of the absorbent article and the lower surface of the absorber may be disposed on the top sheet side of the absorbent article.

< absorbent body >

As shown in fig. 2, the absorbent body 17 of the present embodiment includes an absorbent core 21 and core wrap sheets 26 provided above and below the absorbent core 21 in the thickness direction T so as to wrap the absorbent core 21 inside. The absorbent core 21 includes a high-absorbent polymer, the core wrap sheet 26 is a flat water-absorbent nonwoven fabric in which water-absorbent fibers are entangled with each other, and as shown in fig. 4, the water-absorbent nonwoven fabric has a plurality of high-density portions 32 extending in the longitudinal direction L and arranged in a row in the width direction W, and a plurality of low-density portions 33 extending in the longitudinal direction L and arranged between adjacent high-density portions 32 of the plurality of high-density portions 32. In the present invention, the core wrap sheet may not be configured to house the absorbent core therein, and may be provided at least one of above and below the absorbent core in the thickness direction.

Since the core wrap sheet 26 is flat, in the disposable diaper 1 using this absorbent body 17, a gap is not easily generated between the core wrap sheet 26 and the top sheet 3. Therefore, the body fluid absorbed by the topsheet 3 is transferred to the core wrap sheet 26 and then easily absorbed by the absorbent body 17.

In this case, since the core wrap sheet 26 is a water-absorbent nonwoven fabric in which water-absorbent fibers are entangled, the entanglement between the water-absorbent fibers is loosened by moisture when the core wrap sheet is wet, and the water-absorbent fibers themselves are also liable to stretch by moisture. Therefore, as shown in fig. 3, by allowing the core wrap sheet 26 to absorb body fluid, the core wrap sheet 26 can be relatively easily extended, and the ability to follow swelling of the super absorbent polymer can be improved. As shown in fig. 4, the core wrap sheet 26 has a low-density portion 33, and the low-density portion 33 is likely to be elongated when a load is applied. Therefore, even when the super absorbent polymer swells, the core wrap sheet 26 can be easily stretched as shown in fig. 3, and the following ability to the swelling of the super absorbent polymer can be improved. This can improve the absorption performance of the super absorbent polymer and hence the absorbent body 17.

The core wrap sheet 26 has the high-density portion 32, and the high-density portion 32 allows the body fluid absorbed by the absorber 17 to easily spread in the longitudinal direction L. Therefore, the body fluid can be absorbed over a wide range up to the vicinity of both ends in the longitudinal direction of the absorber 17, and the repeated absorbability in the case of repeated absorption of body fluid is excellent.

The thickness of the absorbent body of the present invention is preferably 0.8mm to 3 mm.

[ absorbent core ]

The absorbent core 21 included in the absorbent body 17 of the present embodiment is disposed between the top sheet 3 and the back sheet 5 together with the core wrap sheet 26 in the disposable diaper 1. The absorbent core 21 included in the absorbent body 17 of the present embodiment has a planar shape of a substantially rectangular shape in which the dimension in the longitudinal direction L is longer than the dimension in the width direction W, and has a constant dimension in the thickness direction T. However, the planar shape of the absorbent core provided in the absorbent body of the present invention is not limited to the planar shape of the substantially rectangular shape, and any planar shape may be adopted within a range that does not impair the function of the absorbent core to absorb and retain liquid.

In the present embodiment, the absorbent core 21 contains a super absorbent polymer, but in the present invention, it is preferable that the absorbent core contains pulp fibers as necessary. The superabsorbent polymer of the absorbent body of the present invention preferably has a basis weight of 50g/m²Above and 500g/m²Hereinafter, the basis weight of the pulp fiber is preferably 0g/m²Above and 1000g/m²The following. In addition, the ratio of the weight per unit area of the super absorbent polymer contained in the absorbent body of the present invention to the weight per unit area of the pulp fibers is preferably 1: 6-6: 0.

in the present embodiment, the absorbent core 21 is a laminated absorbent core in which the 1 st absorbent core layer 18, the intermediate layer 19, and the 2 nd absorbent core layer 20 are laminated with adhesive layers in the order of the 1 st absorbent core layer 18, the intermediate layer 19, and the 2 nd absorbent core layer 20 from the upper surface 34 toward the lower surface 35. However, in the present invention, the absorbent core is not limited to the laminated absorbent core described above, and may be composed of a single and substantially uniform layer of a super absorbent polymer. In the present invention, examples of the adhesive used as needed include a hot melt adhesive.

(1 st absorbent core layer)

In the present embodiment, the 1 st absorbent core layer 18 is a layer of a super absorbent polymer disposed on the upper surface 34 side of the intermediate layer 19, and is formed by holding a certain amount of the super absorbent polymer in the intermediate layer 19 with an adhesive. Furthermore, the 1 st absorbent core layer 18 is sandwiched between the intermediate layer 19 and the core wrap sheet 26. In the 1 st absorbent core layer 18, the super absorbent polymers are arranged substantially uniformly in the planar direction, but the super absorbent polymers may not be arranged substantially uniformly in the planar direction in the 1 st absorbent core layer of the present invention. In the present invention, the superabsorbent polymer of the 1 st absorbent core layer preferably has a weight per unit area of 25g/m²Above and 250g/m²The following. By setting the basis weight of the absorbent polymer within the above range, the absorbent body of the present invention can sufficiently absorb body fluid in excrement and can suppress the occurrence of blocking of the swollen superabsorbent polymer to some extent. Further, in the present invention, the 1 st absorbent core layer may also have pulp fibers, and the weight per unit area of the pulp fibers in this case is preferably more than 0g/m²And 500g/m²The following. By including pulp fibers in the 1 st absorbent core layer, the absorption rate of the absorbent body can be increased. On the other hand, inWhen pulp fibers are contained, the absorbent body can be configured to have a thin structure. In the present invention, the ratio of the weight per unit area of the super absorbent polymer of the 1 st absorbent core layer to the weight per unit area of the pulp fibers is preferably 1: 6-6: 0.

in the present embodiment, the dimension in the width direction W of the 1 st absorbent core layer 18 is smaller than the dimension in the width direction W of the 2 nd absorbent core layer 20 described later over the entire length in the longitudinal direction L. As shown in fig. 2, the 1 st absorbent core layer 18 is disposed so that the center line of the 1 st absorbent core layer 18 in the width direction W substantially overlaps the center line of the absorbent body 17 in the width direction W, and both ends of the 1 st absorbent core layer 18 in the width direction W are located closer to the center of the width direction W than the respective ends of the 2 nd absorbent core layer 20 in the width direction W. By adopting such a structure, even when the body fluid is hardly absorbed by the 1 st absorbent core layer 18, the body fluid can reach the surface of the 2 nd absorbent core layer 20 having a wide width on the surface of the 1 st absorbent core layer 18 in the width direction W. That is, the body fluid which is not absorbed by the 1 st absorbent core layer 18 can be absorbed by the 2 nd absorbent core layer 20, and the absorbent body 17 can stably absorb the discharged body fluid even when the body fluid is discharged repeatedly, and thus the body fluid repeated absorbability is excellent. In the present invention, the dimension in the width direction of the 1 st absorbent core layer may be the same as the dimension in the width direction of the 2 nd absorbent core layer, or may be larger than the dimension in the width direction of the 2 nd absorbent core layer.

In the present invention, "the dimension in the width direction of the 1 st absorbent core layer" and "the dimension in the width direction of the 2 nd absorbent core layer" are defined as dimensions that mean the maximum length of the region of the 1 st absorbent core layer and the 2 nd absorbent core layer sandwiched by the outermost edges in the width direction.

(super absorbent Polymer)

In the present invention, the superabsorbent polymer is intended to absorb and retain liquid in excrement in the absorbent body, and the type thereof is not limited within a range that can achieve the purpose. More specifically, examples of the super absorbent polymer include polyaspartate polymers, sodium polyacrylate polymers, isobutylene-anhydrous maleic acid copolymers, starch-acrylic acid graft copolymers, acrylic acid-vinyl alcohol copolymers, and the like.

In the present invention, among the above-mentioned polymers and copolymers, a super absorbent polymer which is a polymer or a granulated product of the copolymer produced by reversed-phase suspension polymerization is preferably used. The super absorbent polymer as the polymer or copolymer particles produced by inverse suspension polymerization means polymer or copolymer particles obtained by polymerizing a composition containing a polymerizable monomer as a water-in-oil emulsion in the presence of a surfactant or an emulsifier. Since the surface area of the granulated highly absorbent polymer is larger than the surface area of a truly spherical highly absorbent polymer having the same volume, the specific surface area of the whole granulated highly absorbent polymer becomes large, and the absorption rate of the highly absorbent polymer becomes high. Examples of such a super absorbent polymer include those obtained by the production method described in Japanese patent application laid-open No. 57-094011.

(intermediate layer)

As described above, the absorbent core 21 of the absorbent body 17 of the present embodiment is a laminated absorbent core in which the intermediate layer 19 is present between the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20. With such a configuration, in the intermediate layer 19 sandwiched between the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20, the body fluid easily penetrates in the longitudinal direction L and the width direction W, and the contact area between the absorbent body 17 and the body fluid can be increased, so that the body fluid repeat absorbability of the absorbent body 17 is excellent. As will be described later, in the present embodiment, the absorbent body 17 has the joining portions 29 at both ends E in the width direction, at which the 1 st core wrap sheet portion 24 and the intermediate layer 19 are joined. However, in the present invention, the absorbent core is not limited to the mode having the intermediate layer. In the present invention, the intermediate layer is preferably a liquid-permeable nonwoven fabric having hydrophilicity and liquid permeability, and the liquid-permeable nonwoven fabric is preferably a through-air nonwoven fabric made of thermoplastic synthetic fibers. The intermediate layer is a liquid-permeable nonwoven fabric, so that liquid permeability can be ensured even when the absorbent body absorbs water. In addition, since the through-air nonwoven fabric made of thermoplastic synthetic fibers is generally bulky and excellent in cushioning properties, even when the first absorbent core layer 1 and the second absorbent core layer 2 swell, the liquid-permeable nonwoven fabric is a through-air nonwoven fabric made of thermoplastic synthetic fibers, and therefore, the liquid-permeable nonwoven fabric is less likely to impair the diffusion properties of the body fluid in the intermediate layer, and the absorbent body is excellent in repeated absorption of the body fluid. In particular, since the above-described through-air nonwoven fabric is formed of a nonwoven fabric in which fibers are thermally fused, the through-air nonwoven fabric has a certain resistance against an external load, and even when the super absorbent polymer contained in the absorbent body absorbs water and swells, the absorbent body can be effectively prevented from being deformed.

In the present invention, as the thermoplastic synthetic fibers constituting the above-described through-air nonwoven fabric, it is preferable to use sheath-core conjugate fibers using a thermoplastic resin as at least a sheath component constituting the fiber surface. By using a thermoplastic resin as the sheath component constituting the fiber surface, the fiber exhibits thermal fusion characteristics, and therefore the resin component used as the core component can be appropriately selected in accordance with the desired physical properties of the intermediate layer. For example, by using a composite fiber in which a resin component having relatively high strength is used as a core component that does not constitute the fiber surface as the sheath-core composite fiber, an intermediate layer having more stable resistance to tensile stress and the like can be provided. Examples of the resin that can be used as the core component and the sheath component include polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, and ionomer resin; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polylactic acid; polyamides such as nylon and the like are appropriately selected and used in combination. In the present embodiment, for the purpose of achieving both the heat-sealing property and the tensile strength, a polyolefin resin such as polyethylene or polypropylene is preferably used as the sheath component, and the above-mentioned polyolefin resin or a polyester resin such as polyethylene terephthalate is preferably used as the core component.

In the present invention, the weight per unit area of the intermediate layer is preferably 9g/m²Above and 100g/m²In the following, the following description is given,more preferably 12g/m²Above and 60g/m²The following. In the present invention, the thickness of the intermediate layer is preferably 0.1mm or more and 5mm or less, and more preferably 0.15mm or more and 3mm or less. In the present invention, the intermediate layer preferably has a stiffness of 60mm to 160mm in the MD direction, as measured by a cantilever method described later. Further, the 30% tensile strength of the intermediate layer in the CD direction is preferably 0.3N/25mm or more and 6N/25mm or less. By setting the basis weight, thickness, stiffness, and tensile strength of the intermediate layer within the above ranges, the intermediate layer can ensure liquid permeability even after the super absorbent polymer absorbs water, and can maintain the shape of the absorbent body satisfactorily, thereby effectively preventing the absorbent body from deforming.

In the present embodiment, since the intermediate layer 19 is required to have relatively strong physical strength, three-dimensional irregularities are not formed in the intermediate layer 19 by gear processing and embossing, which will be described later. By providing the intermediate layer 19 as a member that is not subjected to gear machining or embossing, resistance to external loads such as tensile stress can be improved. However, in the present invention, the intermediate layer may be provided with irregularities within a range that does not impair the tensile properties of the intermediate layer, thereby improving the apparent bulkiness of the intermediate layer and improving the retention performance with respect to the super absorbent polymer.

(No. 2 absorbent core layer)

The absorbent core 21 included in the absorbent body 17 of the present embodiment includes the 2 nd absorbent core layer 20 so as to be held on the lower surface 35 side of the intermediate layer 19, and the 2 nd absorbent core layer 20 is sandwiched between the intermediate layer 19 and the core wrap sheet 26. The structure of the 2 nd absorbent core layer 20 is substantially the same as that of the 1 st absorbent core layer 18 except for the aspects specifically described below. In the present invention, the 2 nd absorbent core layer contains a super absorbent polymer and, if necessary, pulp fibers, and the weight per unit area of the super absorbent polymer and the weight per unit area of the pulp fibers may be the same as the weight per unit area of the super absorbent polymer and the weight per unit area of the pulp fibers in the 1 st absorbent core layer, may be larger than the weight per unit area of the super absorbent polymer and the weight per unit area of the pulp fibers in the 1 st absorbent core layer, or may be smaller than the weight per unit area of the super absorbent polymer and the weight per unit area of the pulp fibers in the 1 st absorbent core layer.

As shown in fig. 2, in the present embodiment, the 2 nd absorbent core layer 20 includes two superabsorbent polymer-nonexisting regions 28 that are provided extending in the longitudinal direction L and in which superabsorbent polymer is nonexistent in the thickness direction T. Here, the super absorbent polymer swells by absorbing water, and tends to be difficult to transmit liquid due to blocking. Since the second absorbent core layer 20 includes the high absorbent polymer nonexistent region 28, the bodily fluid can be diffused in the longitudinal direction L by the high absorbent polymer nonexistent region 28, and thus the diffused bodily fluid easily penetrates into the absorbent body 17, and the repeated absorbency of the bodily fluid by the absorbent body 17 is excellent. In particular, in the present embodiment, since the 2 nd absorbent core layer 20 is positioned on the garment side of the intermediate layer 19, the absorbent body 17 can easily absorb body fluid accumulated on the garment side of the absorbent body 17. In the present invention, even when the 2 nd absorbent core layer including the super absorbent polymer non-existing region is positioned closer to the skin side than the intermediate layer, it is predicted that the permeation of body fluid from the skin side toward the garment side is promoted by the presence of the super absorbent polymer non-existing region.

In the present invention, the number of the regions of the 2 nd absorbent core layer where no superabsorbent polymer is present is not limited to two, and is preferably 1 to 4, more preferably two or 3, in the width direction of the 2 nd absorbent core layer over the full width in the width direction, from the viewpoint of maintaining the absorption performance of the absorbent body and effectively preventing blocking. In the present invention, when there are 3 or more regions where no superabsorbent polymer is present, the regions where no superabsorbent polymer is present, which extend in the longitudinal direction, are preferably provided at regular intervals on the 2 nd absorbent core layer with the widthwise center line as the center, and the width thereof is preferably 5mm to 60 mm.

In the absorbent body of the present invention, the superabsorbent polymer-free region may be present in the 1 st absorbent core layer in addition to the 2 nd absorbent core layer. In this case, the number of the regions where the super absorbent polymer of the 1 st absorbent core layer is absent may be at least more than the number of the regions where the super absorbent polymer of the 2 nd absorbent core layer is absent or may be the same as the number of the regions where the super absorbent polymer of the 2 nd absorbent core layer is absent. Further, the region of the first absorbent core layer where the superabsorbent polymer is not present and the region of the second absorbent core layer where the superabsorbent polymer is not present may overlap with each other or may be different from each other in the width direction W.

In the present invention, in the case where the region where the super absorbent polymer does not exist is present in the 1 st absorbent core layer and/or the 2 nd absorbent core layer, the widthwise dimension of the 1 st absorbent core layer and/or the 2 nd absorbent core layer means the widthwise dimension of the region including the region where the super absorbent polymer does not exist.

[ core cladding sheet ]

Fig. 4 is an enlarged perspective view of the core wrap sheet 26 provided in the absorber 17 of the present embodiment. As described above, the core wrap sheet 26 of the present embodiment is provided above and below the absorbent core 21 in the thickness direction T so as to wrap the absorbent core 21 inside. The core wrap sheet 26 is a flat water-absorbent nonwoven fabric in which water-absorbent fibers are entangled with each other, and as shown in fig. 4, the water-absorbent nonwoven fabric has a plurality of high-density portions 32 extending in the longitudinal direction L and arranged in a row in the width direction W, and a plurality of low-density portions 33 extending in the longitudinal direction L and arranged between adjacent high-density portions 32 of the plurality of high-density portions 32. The core wrap sheet 26 included in the absorber 17 of the present embodiment is flat. In the disposable diaper 1 using the absorber 17 including the flat core wrap sheet 26, a gap is less likely to be generated between the core wrap sheet 26 and the top sheet 3. Therefore, the body fluid absorbed by the topsheet 3 is easily transferred to the core wrap sheet 26 and easily absorbed by the absorbent body 17. As shown in fig. 4, in the present embodiment, the core wrap sheet 26 has repeated irregularities in a partial region, and the height difference T between the concave portion and the convex portion in one surface of the core wrap sheet 26 is about 1 time the thickness d of the core wrap sheet 26 in the thickness direction T. In the present invention, the "flat" core wrap sheet means a state in which the core wrap sheet has substantially no repeating irregularities or, even if there are repeating irregularities, the level difference between the concave portions and the convex portions in one surface of the core wrap sheet is 3 times or less, preferably 2.5 times or less, and more preferably 1.2 times or less the thickness of the core wrap sheet in the thickness direction. In the present invention, the core wrap sheet may be formed of one piece of nonwoven fabric, or may be formed by joining a plurality of pieces of nonwoven fabric to each other, and may be provided at least one of above and below the absorbent core in the thickness direction.

In the present embodiment, as shown in fig. 3, even when the absorbent body 17 absorbs body fluid and the superabsorbent polymer swells toward the upper surface 34 and the lower surface 35, the core wrap sheet 26 can follow the swelling, and the absorption performance of the superabsorbent polymer, and thus the absorbent body 17, can be improved.

Further, the high-density portion 32 of the core wrap sheet 26 of the present embodiment makes it easy for the body fluid absorbed by the absorber 17 to spread in the longitudinal direction L. Therefore, the body fluid can be absorbed over a wide range up to the vicinity of both ends in the longitudinal direction of the absorber 17, and the repeated absorbability in the case of repeated absorption of body fluid is excellent.

In the present invention, since the water-absorbent nonwoven fabric in which the water-absorbent fibers are entangled is loosened by entanglement between the fibers due to moisture and the water-absorbent fibers themselves are easily stretched due to moisture, the core wrap sheet can be relatively easily stretched by allowing the core wrap sheet to absorb body fluid. Further, since the low-density portion of the core wrap sheet is easily elongated when a load is applied, the core wrap sheet can be easily elongated even when the super absorbent polymer swells.

(high density part and Low density part)

As shown in fig. 4, in the present embodiment, the core wrap sheet 26 has a plurality of high-density portions 32 extending in the longitudinal direction L and arranged in a row in the width direction W, and a plurality of low-density portions 33 extending in the longitudinal direction L and arranged between adjacent high-density portions 32 of the plurality of high-density portions 32, respectively, and the high-density portions 32 are arranged at both ends in the width direction W of the core wrap sheet 26. In the present invention, the distance in the width direction of the adjacent high-density portions is preferably 0.1mm or more and 1mm or less, and the distance in the width direction of the adjacent low-density portions is preferably 0.3mm or more and 4mm or less. When one low-density portion and one high-density portion are adjacent to each other, the distance of the repeating unit is preferably 0.4mm or more and 5mm or less. In the present invention, when the high-density portions are disposed at both ends in the width direction of the core wrap sheet, the dimension in the width direction of the high-density portions located at both ends in the width direction is preferably 3mm to 20 mm.

In the present invention, it is preferable that the water-absorbent fibers located in the high-density portion have an orientation along the longitudinal direction, and the water-absorbent fibers located in the low-density portion have an orientation lower than that of the fibers located in the high-density portion. This makes it easy for the high-density portion of the water-absorbent fibers having a high density to diffuse body fluid in the longitudinal direction, and the low-density portion to stretch in the width direction.

(Water-absorbent nonwoven Fabric)

In the absorbent body of the present invention, the water-absorbent fibers constituting the core wrap sheet are preferably regenerated cellulose fibers, and more preferably rayon fibers. Since regenerated cellulose fibers such as rayon fibers are superior to pulp fibers in fiber uniformity (fiber length, fiber diameter, and the like), the core wrap sheet has better extensibility in the wet state and the absorbent performance of the super absorbent polymer of the absorbent body is superior. On the other hand, in the water-absorbent nonwoven fabric formed by entangling regenerated cellulose fibers such as rayon fibers, a relatively high tensile force acts when a load is applied from the outside of the absorbent body or when the absorbent body is intended to be stretched at a displacement amount of a certain degree or more, and therefore, the absorbent body can be made to have a property of being less likely to cause running during wetting, that is, a good shape-retaining property during wetting of the absorbent body.

In the absorbent body of the present invention, the water-absorbent nonwoven fabric constituting the core wrap sheet is preferably a spunlace nonwoven fabric made of water-absorbent fibers, and more preferably a spunlace nonwoven fabric made of regenerated cellulose fibers (e.g., rayon fibers). Here, as the spunlace nonwoven fabric which can be used as the core-covering sheet, there can be mentioned a spunlace nonwoven fabric in which the fibers constituting the nonwoven fabric are mainly rayon, and from the viewpoint of elongation characteristics at the time of moisture absorption, a spunlace nonwoven fabric in which at least 85 mass% of the fibers constituting the nonwoven fabric are rayon is preferable, a spunlace nonwoven fabric in which at least 90 mass% are rayon is more preferable, and a spunlace nonwoven fabric substantially composed of only rayon is further preferable.

In the present invention, as the fiber component other than the regenerated cellulose fiber constituting the spunlace nonwoven fabric, any hydrophilic fiber can be cited. For example, the spunlace nonwoven fabric may be a spunlace nonwoven fabric containing rayon fibers and pulp fibers. Examples of such a spunlace nonwoven fabric containing rayon fibers and pulp fibers include a spunlace nonwoven fabric composed of an upper layer containing 80% to 100% of rayon fibers, a middle layer containing 80% to 100% of pulp fibers, and a lower layer containing 80% to 100% of rayon fibers. The weight per unit area of the core wrap sheet of the present invention is preferably 15g/m²Above and 200g/m²Hereinafter, more preferably 25g/m²Above and 150g/m²The thickness d is preferably 0.1mm to 2mm, more preferably 0.2mm to 1.5 mm. By setting the weight per unit area and the thickness of the core wrap sheet within the above ranges, the elongation property and the strength of the core wrap sheet can be both satisfied.

(1 st core wrap sheet part and 2 nd core wrap sheet part)

In the present embodiment, the core wrap sheet 26 includes: a 1 st core wrap sheet portion 24 located above the thickness direction center plane Tc of the absorber 17; and a 2 nd core wrap sheet portion 25 located below a thickness direction center plane Tc of the absorber 17, the thickness direction center plane Tc being a plane passing through the center of the absorber 17 in the thickness direction T at a position having the largest dimension in the thickness direction T and being parallel to the width direction W and the longitudinal direction L. The core wrap sheet 26 described above surrounds the laminated absorbent core in the width direction W to enclose the laminated absorbent core inside. According to the present embodiment, since the high-density portion 32 described above can diffuse the body fluid over a wide range in the longitudinal direction, the absorbent body 17 is excellent in repeated absorption of the body fluid. Further, even when the super absorbent polymer swells, the absorption performance of the super absorbent polymer is increased by the extension of the low density portion 33 described above.

In the present invention, the 1 st core wrap sheet part and the 2 nd core wrap sheet part may be separate independent sheets or may be different parts of a single sheet which are not separate. In the case where the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion are formed as separate single sheets, the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion may be joined along the longitudinal direction at both widthwise ends. As described later, the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion may be in a state in which at least a part of the plurality of sheets is joined.

(center sheet part and outer sheet part)

In the present embodiment, the 1 st core wrap sheet portion 24 includes a center sheet portion 22 disposed at a position close to the center in the width direction W and a pair of outer sheet portions 23 disposed on both outer sides in the width direction W. Both ends in the width direction W of the center sheet portion 22 overlap with the ends in the width direction W of the center sheet portion 22 of the pair of outer sheet portions 23 in the thickness direction T, and overlap with a pair of overlapping portions 27 extending in the longitudinal direction L. By having the above-described structure for the 1 st core wrap sheet portion 24, the fiber density of the water-absorbent fibers in the pair of overlapping portions 27 can be further increased, and the body fluid can be more easily diffused in the longitudinal direction L in the pair of overlapping portions 27. This provides the absorbent body 17 with excellent repeated diffusion of body fluid. In addition, as shown in fig. 2, in the present embodiment, the outer sheet portions 23 and the central sheet portion 22 respectively constitute at least a part of the core wrap sheet that is different from each other in a separated manner, the central sheet portion 22 constitutes one sheet, and the 2 nd core wrap sheet portion 25 and the pair of outer sheet portions 23 are integrated to constitute the other sheet.

In the present embodiment, as shown in fig. 3, in each overlapping portion 27 of the pair of overlapping portions 27, the pair of outer sheet portions 23 are respectively disposed on the upper surface 34 side of the center sheet portion 22, and the edge portions 31 of the pair of outer sheet portions 23 on the center sheet portion 22 side are separated from the center sheet portion 22. With such a configuration, as shown in fig. 3, when the intermediate portion C in the width direction of the laminated absorbent core absorbs bodily fluids and swells, the upper surface 34 of the absorbent body 17 is inclined, so that the edge portion 31 of the outer sheet portion 23 overlapping the center sheet portion 22 floats from the surface of the center sheet portion 22, and the edge portion 31 of the outer sheet portion 23 can function as a leakage preventing wall.

In the present embodiment, as described above, the dimension in the width direction W of the 1 st absorbent core layer 18 is smaller than the dimension in the width direction W of the 2 nd absorbent core layer 20, and the pair of overlapping portions 27 are disposed at both width direction end portions E. With such a configuration, the superabsorbent polymer derived from the 1 st absorbent core layer 18 is not present at the portion where the pair of superposed portions 27 are present, and therefore, the bodily fluid easily spreads in the longitudinal direction L in the pair of superposed portions 27 and permeates into the 2 nd absorbent core layer 20, and the absorbent body 17 is excellent in repeated absorbency of bodily fluid.

In the present invention, the high-density portions may be disposed at both ends in the width direction of the core wrap sheet. For example, it is preferable that the high-density portions are disposed at both ends in the width direction of the sheet including the center sheet portion, and the high-density portions are disposed at both ends in the width direction of the sheet including the outer sheet portion. With such a configuration, the fiber density of the water-absorbent fibers in the pair of superposed portions becomes higher, and the liquid permeability along the longitudinal direction is further improved, so that the liquid diffusibility in the pair of superposed portions can be further improved, and the body fluid repeated absorbability of the absorbent body can be improved.

(Joint and intermediate Joint)

As shown in fig. 2, in the present embodiment, the absorbent body 17 has a joining portion 29 where the 1 st core wrap sheet portion 24 and the intermediate layer 19 are joined at both end portions E in the width direction. By providing the joining portions 29 at both the ends E in the width direction, as shown in fig. 3, even when the absorbent body 17 absorbs water, the core wrap sheet 26 can be supported by the intermediate layer 19 having high resistance to tensile stress, and therefore the absorbent body 17 has good shape retention properties when wet. In addition, in the present embodiment, the 2 nd absorbent core layer 20 has a high absorbent polymer nonexistent region 28, but the absorbent body 17 has an intermediate joint portion 30 where the 2 nd core wrap sheet 26 and the intermediate layer 19 are joined in this high absorbent polymer nonexistent region 28. This improves the shape retention property of the absorber 17 when wet. However, in the present invention, the joint portion may be formed by joining the 2 nd core wrap sheet portion and the intermediate layer, and the intermediate joint portion may be formed by joining the 1 st core wrap sheet portion and the intermediate layer.

< method for producing absorbent body >

In the production of the absorbent body of the present invention, the production can be basically performed according to the conventional production method of the absorbent body.

In the case where the absorbent body of the present invention has a structure in which the absorbent core, which is formed by stacking the 1 st absorbent core layer, the intermediate layer, and the 2 nd absorbent core layer in this order from the upper surface side toward the lower surface side, is enclosed by the lower core wrap sheet and the upper core wrap sheet, the absorbent body can be produced by the following production method.

First, a hot melt adhesive is applied to the continuous sheet for the core wrap sheet of the lower layer while moving the continuous sheet for the core wrap sheet of the lower layer in the longitudinal direction L. Next, the superabsorbent polymer is dispersed from the superabsorbent polymer supply device along the longitudinal direction L in both end portions and a central portion in the width direction W of the continuous sheet for a core wrap sheet of the lower layer to which the hot melt adhesive is applied. Next, a continuous sheet of the intermediate layer 19 coated on both sides with hot melt adhesive is laminated on the underlying superabsorbent polymer for the core wrap sheet. Next, while moving the laminate in the longitudinal direction L, the superabsorbent polymer is dispersed from another superabsorbent polymer supplying device along the longitudinal direction L on both end portions and a central portion in the width direction W of the continuous sheet for the intermediate layer 19 to which the hot melt adhesive is applied. Next, the continuous sheet for the core wrap sheet of the upper layer to which the hot melt adhesive is applied is laminated on the super absorbent polymer on the continuous sheet for the core wrap sheet of the lower layer so that the hot melt adhesive is on the super absorbent polymer side. Then, after both side portions in the width direction W of the continuous sheet for the core wrap sheet of the lower layer are folded back onto the continuous sheet for the core wrap sheet of the upper layer, the laminate is pressed by a pair of press rolls to adjust the thickness, thereby forming the absorbent body 17.

In the present invention, it is preferable that the high-density portion and the low-density portion of the water-absorbent nonwoven fabric are formed by subjecting a nonwoven fabric formed by hydroentanglement to gear processing. The gear processing is performed by loading the original roll sheet between shaping devices provided with a pair of upper and lower stretching rollers to be described later and stretching the original roll sheet; the pair of upper and lower stretching rolls have a plurality of ridges provided in parallel with each other at a constant interval in the roll width direction along the outer peripheral surface and grooves between adjacent ridges, and the ridges of one stretching roll are engaged with the grooves of the other stretching roll. Here, since the portion between the two portions fixed adjacent to each other is extended in a state where the portion sandwiched between the top portion of the ridge and the bottom portion of the groove is fixed, the portion where the top portion of the ridge and the bottom portion of the groove are fixed becomes the high-density portion, and the portion sandwiched between the adjacent high-density portions becomes the low-density portion. In addition, in general, when a nonwoven fabric having high stiffness is subjected to gear processing, unevenness may remain on the surface of the nonwoven fabric, and the nonwoven fabric may become uneven. In the present invention, it is preferable that the stiffness of the core wrap sheet is adjusted by adjusting the basis weight and thickness of the nonwoven fabric constituting the core wrap sheet, the material of the water-absorbent fibers, and the like so that the core wrap sheet is flat even when gear processing is performed.

When the disposable diaper 1 is manufactured using the absorber 17 of the present embodiment, the upper surface 34 is disposed on the skin side and the lower surface 35 is disposed on the garment side. However, the absorbent article including the absorbent body of the present invention may be configured such that the upper surface of the absorbent body is disposed on the clothing side and the lower surface is disposed on the skin side, and the water-absorbent nonwoven fabric may be disposed between the absorbent core and the top sheet or between the absorbent core and the back sheet.

(embodiment 2)

Hereinafter, embodiment 2 for solving problem 2 of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a tape-fixed disposable diaper 1 (hereinafter also simply referred to as "one") including an absorber 17 of the present embodimentDisposable diaper "), figure 2 is a top development view taken along W of figure 1₁－W₁FIG. 3 is a cross-sectional view of the absorbent body 17 before absorption of bodily fluids, taken along line W in FIG. 1₁－W₁A cross-sectional view of the absorbent body 17 after absorption of the bodily fluid of the face. As shown in fig. 1 and 2, the absorbent body 17 of the present embodiment has a 1 st surface 34 and a 2 nd surface 35, has a longitudinal direction L, a width direction W, and a thickness direction T orthogonal to each other, and is divided into two width-direction end portions E and a width-direction intermediate portion C along the width direction W. Here, the width direction middle portion C is a region extending to about 70% of the width direction W centering on the center point of the width direction W of the portion having the largest dimension in the width direction W, and regions of about 15% of each of the left and right sides on both outer sides thereof are defined as both width direction end portions E. The longitudinal direction L of the disposable diaper 1 coincides with the longitudinal direction L of the absorber 17, the width direction W of the disposable diaper 1 coincides with the width direction W of the absorber 17, and the thickness direction T of the disposable diaper 1 coincides with the thickness direction T of the absorber 17. The absorbent article of the present invention is not limited to the tape-fixed disposable diaper, and may be, for example, a pants-type disposable diaper, a urine-absorbing pad, a light incontinence pad, a sanitary pad, or a panty liner.

The disposable diaper 1 includes a liquid-permeable top sheet 3, a liquid-impermeable back sheet 5, an absorbent body 17 of the present embodiment disposed between the top sheet 3 and the back sheet 5, and further includes a leakage preventing wall 7 having an elastic member 9, a fastening tape 15, and the like. In the present embodiment, the absorber 17 is disposed between the top sheet 3 and the back sheet 5 such that the 1 st surface 34 is positioned on the top sheet 3 side of the disposable diaper 1 and the 2 nd surface 35 is positioned on the back sheet 5 side of the disposable diaper 1. However, in the present invention, the 1 st surface of the absorbent body may be disposed on the back sheet side of the absorbent article, and the 2 nd surface of the absorbent body may be disposed on the top sheet side of the absorbent article.

< absorbent body >

As shown in fig. 1, the absorbent body 17 of the present embodiment is applied to a disposable diaper 1. As shown in fig. 2, the absorbent body 17 of the present embodiment includes a core wrap sheet 26 and a laminated absorbent core 21, the laminated absorbent core 21 is formed by laminating a 1 st absorbent core layer 18, an intermediate layer 19, and a 2 nd absorbent core layer 20 in this order from a 1 st face 34 toward a 2 nd face 35, and the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20 contain a super absorbent polymer. The core wrap sheet 26 includes: a 1 st core wrap sheet portion 24 located closer to the 1 st surface 34 side than the thickness direction center surface Tc of the absorber 17; and a 2 nd core wrap sheet portion 25 located closer to the 2 nd surface 35 side than a thickness direction center surface Tc of the absorber 17, the thickness direction center surface Tc being a surface parallel to the width direction W and the longitudinal direction L passing through the center in the thickness direction T of the portion having the largest dimension in the thickness direction T of the absorber 17. In the present embodiment, the absorbent body 17 has a joint 29 where the intermediate layer 19 is joined to both the 1 st core wrap sheet portion 24 and the 2 nd core wrap sheet portion 25.

In the present invention, the 1 st core wrap sheet portion has a water-absorbent nonwoven fabric comprising water-absorbent fibers containing water-absorbent fibers having a fiber length of 25mm or more entangled with each other, the water-absorbent nonwoven fabric has an elongation in a wet tensile test that is larger than an elongation in a dry tensile test and a tensile strength in a wet tensile test that is lower than a tensile strength in a dry tensile test, the intermediate layer is a heat-fused nonwoven fabric in which a plurality of thermoplastic synthetic fibers are fused together, the elongation in the wet tensile test of the heat-fused nonwoven fabric is in a range of 90% to 110% of the elongation in the dry tensile test, and the tensile strength in the wet tensile test of the heat-fused nonwoven fabric is in a range of 90% to 110% of the tensile strength in the dry tensile test.

As described above, in the present embodiment, even if the intermediate layer 19 absorbs water, the elongation characteristics thereof are rarely changed, and the 1 st core wrap sheet portion 24 is joined to the intermediate layer 19. Therefore, as shown in fig. 3, even if the 1 st core wrap sheet portion 24 elongates (deforms) due to the absorbent polymer absorbing water and swelling, the deformation of the entire absorbent body 17 can be suppressed by the intermediate layer 19 that is less likely to elongate (deform). This makes the absorber 17 excellent in shape retention in the wet state, i.e., in shape retention in the wet state.

Further, since the intermediate layer 19 included in the absorbent body 17 of the present embodiment is formed by fusing thermoplastic fibers to each other, the characteristics with respect to the load are not easily changed at the time of drying and at the time of wetting, and therefore the intermediate layer is not easily stretched at the time of wetting, and the intermediate layer 19 is not easily crushed even when the load is received, for example, when the load is received by the high-absorbent polymers of the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20 absorbing water and swelling, as shown in fig. 3. Therefore, even under the condition that the super absorbent polymer swells, the absorbent body 17 has excellent liquid permeability as the permeability of body fluid of the intermediate layer 19, and the diffusibility of body fluid is less likely to be impaired, so that the absorbent body 17 has excellent repeated absorption of body fluid by repeatedly absorbing body fluid.

At least the 1 st core wrap sheet part 24 of the core wrap sheet 26 included in the absorbent body 17 of the present embodiment has a water-absorbent nonwoven fabric made of water-absorbent fibers containing water-absorbent fibers entangled with each other and having a fiber length of 25mm or more, and the elongation in the wet tensile test is larger than the elongation in the dry tensile test, and the tensile strength in the wet tensile test is lower than the tensile strength in the dry tensile test. The 1 st core wrap sheet portion 24 made of a water-absorbent nonwoven fabric has a property of being easily elongated when moisture of body fluid is absorbed, and as shown in fig. 3, when the absorbent body 17 absorbs water, the 1 st core wrap sheet portion 24 absorbs the body fluid that has permeated from the 1 st surface 34 side and is relatively easily elongated. Thus, the absorption performance of the super absorbent polymer can be improved by the elongation of the 1 st core wrap sheet portion 24.

The thickness of the absorbent body of the present invention is preferably 0.8mm to 3 mm.

[ core cladding sheet ]

As shown in fig. 2, in the absorbent body 17 of the present embodiment, the core wrap sheet 26 includes a 1 st core wrap sheet portion 24 and a 2 nd core wrap sheet portion 25, and the 1 st core wrap sheet portion 24 has a water-absorbent nonwoven fabric made of water-absorbent fibers. In the present embodiment, the core wrap sheet 26 wraps the laminated absorbent core 21 so as to surround the laminated absorbent core 21 in the width direction W, thereby wrapping the laminated absorbent core 21 inside.

(1 st core cladding sheet part)

As shown in fig. 2, in the absorbent body 17 of the present embodiment, the 1 st core wrap sheet portion 24 wraps the laminated absorbent core 21 inside together with the 2 nd core wrap sheet portion 25. The 1 st core wrap sheet portion 24 is another sheet separated from the 2 nd core wrap sheet portion 25. Both end portions in the width direction W of the 1 st core wrap sheet portion 24 and the 2 nd core wrap sheet portion 25 are joined to each other along the length direction L. However, in the present invention, the 1 st core wrap sheet portion may not be joined to the 2 nd core wrap sheet portion, or may be a part of a single sheet integrally configured with the 2 nd core wrap sheet portion. At least one of the 1 st and 2 nd core wrap sheet portions may be in a state in which at least a part of the plurality of sheets is joined.

In the present invention, the weight per unit area of the 1 st core wrap sheet portion is preferably 15g/m²Above and 200g/m²Hereinafter, more preferably 25g/m²Above and 150g/m²The thickness is preferably 0.1mm to 2mm, more preferably 0.2mm to 1.5 mm. By setting the weight per unit area and the thickness of the 1 st core wrap sheet portion within the above ranges, the elongation characteristics and the strength of the 1 st core wrap sheet portion can be both satisfied.

(Joint part)

The absorbent body 17 of the present embodiment has, at both ends E in the width direction, joint portions 29 at which the intermediate layer 19, which will be described later, is joined to both the 1 st core wrap sheet portion 24 and the 2 nd core wrap sheet portion 25. In the present embodiment, by joining the intermediate layer 19, which has little change in the water absorption elongation characteristics, to both the 1 st core wrap sheet portion 24 and the 2 nd core wrap sheet portion 25, as shown in fig. 3, even if the 1 st core wrap sheet portion 24 and the 2 nd core wrap sheet portion 25 elongate (deform) due to the superabsorbent polymer absorbing water and swelling, deformation of the entire absorbent body 17 can be suppressed by the intermediate layer 19, which is less likely to elongate (deform). Therefore, the absorbent body 17 has excellent shape retention properties in the wet state, i.e., retains its shape in the wet state. In the present invention, the joint is not limited to the form in which the intermediate layer is joined to both the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion, and may be formed by joining the intermediate layer to either the 1 st core wrap sheet portion or the 2 nd core wrap sheet portion. However, the joint is more preferable in terms of shape retention when the absorbent body is wet, in comparison with the case where one of the 1 st and 2 nd core wrap sheet portions is joined to the intermediate layer, in the case where both the 1 st and 2 nd core wrap sheet portions are joined to the intermediate layer.

In the absorbent body 17 of the present embodiment, the joint portions 29 are located at both widthwise end portions E. By providing the joining portions 29 at both the widthwise end portions E, as shown in fig. 3, even when the absorbent body 17 absorbs water, the core wrap sheet 26 can be supported by the intermediate layer 19 having high resistance to tensile stress, and therefore the absorbent body 17 has good shape retention properties when wet. However, in the present invention, the position of the joining portion is not limited to the widthwise both end portions E of the absorbent body.

(Water-absorbent nonwoven Fabric)

In the absorbent body 17 of the present embodiment, the 1 st core wrap sheet portion 24 has the water-absorbent nonwoven fabric described above. Since the water-absorbent nonwoven fabric is formed by entanglement, the bonding between the fibers of the water-absorbent nonwoven fabric tends to be weakened by water absorption. In addition, the water-absorbent fibers are liable to stretch when absorbing water. Further, since the water-absorbent fibers include water-absorbent fibers having a fiber length of 25mm or more, when the bonding force between the water-absorbent fibers is weakened, the water-absorbent nonwoven fabric is easily stretched without breaking, and the water-absorbent nonwoven fabric is easily stretched due to the elongation of the water-absorbent fibers. Further, the water-absorbent nonwoven fabric has a property of being easily elongated when wet as compared with when dry, so that the absorbent body 17 is prevented from being deformed when an external force is applied before water absorption, and the water-absorbent nonwoven fabric is easily elongated after water absorption. Therefore, when the absorbent body 17 absorbs water, the 1 st core wrap sheet portion 24 absorbs body fluid that has penetrated from the skin side surface side or body fluid that has accumulated on the garment side surface, and relatively easily stretches following the swelling of the super absorbent polymer. Thus, the 1 st core wrap sheet is partially elongated, whereby the absorption performance of the super absorbent polymer can be improved.

Since the absorbent body 17 of the present embodiment has the property that the 1 st core covering sheet portion 24 is easily elongated when wet, as shown in fig. 3, even when the 1 st absorbent core layer 18 absorbs body fluid and the super absorbent polymer swells toward the 1 st surface 34, the 1 st core covering sheet portion 24 can follow the swelling, and the super absorbent polymer and hence the absorbent performance of the absorbent body 17 can be improved. In the present embodiment, the 2 nd core wrap sheet portion 25 also has a water-absorbent nonwoven fabric having the above-described characteristics, and as shown in fig. 3, even when the 2 nd absorbent core layer 20 absorbs body fluid and the super absorbent polymer swells toward the 2 nd surface 35, the 2 nd core wrap sheet portion 25 can follow the swelling, and the absorption performance of the absorbent body 17 can be improved. However, in the present invention, the 2 nd core wrap sheet portion may not necessarily have the water-absorbent nonwoven fabric.

In the present invention, it is preferable that the water-absorbent nonwoven fabric has an elongation of 30% or more in each of a wet tensile test and a dry tensile test, and a 30% elongation tensile strength, which is a tensile strength at 30% elongation of the water-absorbent nonwoven fabric in the wet tensile test, is 25% or less of a 30% elongation tensile strength in the dry tensile test. Thus, the core wrap sheet is easy to follow the swelling of the super absorbent polymer, the absorption performance of the super absorbent polymer is improved, and the absorbent body is less likely to lose its shape before absorbing water, i.e., excellent in shape retention during drying.

More specifically, in the present invention, the maximum elongation in the wet tensile test of the water-absorbent nonwoven fabric is preferably 50% or more and 200% or less in the CD direction, the 30% tensile strength in the CD direction is preferably 0.01N/25mm or more and 1N/25mm or less, and the maximum tensile strength in the CD direction is preferably 1N/25mm or more and 15N/25mm or less. The maximum elongation in the dry tensile test of the water-absorbent nonwoven fabric is preferably 40% or more and 190% or less in the CD direction, the 30% tensile strength in the CD direction is preferably 0.1N/25mm or more and 5N/25mm or less, and the maximum tensile strength in the CD direction is preferably 1.2N/5mm or more and 20N/25mm or less. In the present invention, the CD direction of the water-absorbent nonwoven fabric preferably corresponds to the width direction W of the absorbent article.

In the present invention, the water-absorbent fibers having a fiber length of 25mm or more contained in the water-absorbent fibers constituting the water-absorbent nonwoven fabric are preferably regenerated cellulose fibers (for example, rayon fibers), and more preferably rayon fibers. Since regenerated cellulose fibers such as rayon fibers are superior to pulp fibers in fiber uniformity (fiber length, fiber diameter, and the like), the elongation properties in the wet state of the 1 st core wrap sheet portion become better, and the absorption properties of the super absorbent polymer of the absorbent body become excellent. On the other hand, in the water-absorbent nonwoven fabric formed by entangling regenerated cellulose fibers such as rayon fibers, a relatively high tensile force acts when a load is applied from the outside of the absorbent body or when the absorbent body is intended to be stretched at a displacement of a certain amount or more, and therefore, the shape retention properties of the absorbent body in the wet state can be improved.

In the absorbent body of the present invention, the water-absorbent nonwoven fabric included in the 1 st core wrap sheet portion is preferably a spunlace nonwoven fabric made of water-absorbent fibers, and more preferably a spunlace nonwoven fabric made of regenerated cellulose fibers. Since the spunlace nonwoven fabric is a nonwoven fabric in which entanglement between fibers is likely to occur, the water-absorbent nonwoven fabric is likely to stretch, and the absorbency of the super-absorbent polymer is increased.

In this case, the water-absorbent fibers may contain water-absorbent fibers having a fiber length of less than 25mm, but it is preferable that the water-absorbent fibers mainly contain water-absorbent fibers having a fiber length of 25mm or more, and it is more preferable that the water-absorbent fibers are composed of only water-absorbent fibers having a fiber length of 25mm or more. The water-repellent nonwoven fabric composed of such water-absorbent fibers includes a water-repellent nonwoven fabric in which the fibers constituting the nonwoven fabric are mainly rayon, and is preferably a water-repellent nonwoven fabric in which at least 85 mass% of the fibers constituting the nonwoven fabric are rayon, more preferably a water-repellent nonwoven fabric in which at least 90 mass% are rayon, and still more preferably a water-repellent nonwoven fabric composed of only rayon, from the viewpoint of elongation characteristics at the time of moisture absorption.

In the present invention, as the fiber component other than the regenerated cellulose fiber constituting the spunlace nonwoven fabric, any hydrophilic fiber can be cited. As such a hydrophilic nonwoven fabric, pulp fibers can be cited. For example, the spunlace nonwoven fabric may be a spunlace nonwoven fabric containing rayon fibers and pulp fibers. Examples of such a spunlace nonwoven fabric containing rayon fibers and pulp fibers include a spunlace nonwoven fabric composed of an upper layer containing 80% to 100% of rayon fibers, a middle layer containing 80% to 100% of pulp fibers, and a lower layer containing 80% to 100% of rayon fibers.

(high density part and Low density part)

Fig. 4 is an enlarged perspective view of the water-absorbent nonwoven fabric included in the 1 st core wrap sheet portion 24. As shown in fig. 4, the water-absorbent nonwoven fabric included in the absorbent body 17 of the present embodiment includes a plurality of high-density portions 32, in which the fiber density of the water-absorbent fibers arranged in a row in the width direction W is high, extending in the longitudinal direction L, and a plurality of low-density portions 33, in which the fiber density of the water-absorbent fibers arranged between the adjacent high-density portions 32 of the plurality of high-density portions 32 is low, extending in the longitudinal direction L. Since the plurality of high-density portions 32 facilitate diffusion of body fluid in the longitudinal direction L, the 1 st core wrap sheet portion 24 readily absorbs body fluid that has permeated from the skin side surface side and diffuses the body fluid in the longitudinal direction L. As a result, the absorbent body 17 can absorb body fluid over a wide range up to the vicinity of both ends in the longitudinal direction L, and the ratio of the area of the portion of the absorbent body 17 that absorbs body fluid to the entire area including the surfaces in the longitudinal direction L and the width direction W, that is, the absorption area ratio, increases, and as a result, the absorbent body 17 is excellent in the above-described repeated absorption of body fluid. In the present embodiment, the plurality of low-density portions 33 can facilitate the water-absorbent nonwoven fabric to be stretched in the width direction W of the absorbent body 17. Therefore, the absorption performance of the super absorbent polymer included in the absorbent body 17 of the present embodiment can be improved.

In addition, in the absorbent body of the present invention, the configuration is not limited to the configuration in which the 1 st surface is disposed on the skin side surface side, and a configuration in which the 1 st surface is the garment side surface is also conceivable, but in the case where the 1 st surface is the garment side surface, the 1 st core wrap sheet portion easily absorbs the body fluid that has passed through the absorbent body and diffuses the body fluid in the longitudinal direction when the absorbent body absorbs water.

In the present embodiment, as shown in fig. 4, the water-absorbent nonwoven fabric has irregularities that repeat in the form that the projections and the recesses are located in the high-density portions 32 adjacent to each other in the width direction W, and the height difference T between the recesses and the projections on one surface of the core wrap sheet 26 is about 1 time the thickness d of the core wrap sheet 26 in the thickness direction T. In the present invention, the height difference between the concave portion and the convex portion is preferably 3 times or less, more preferably 2.5 times or less, and further preferably 1.2 times or less the thickness d of the core wrap sheet.

In the present invention, the distance in the width direction of the adjacent high-density portions is preferably 0.1mm or more and 1mm or less, and the distance in the width direction of the adjacent low-density portions is preferably 0.3mm or more and 4mm or less. When one low-density portion and one high-density portion are adjacent to each other, the distance of the repeating unit is preferably 0.4mm or more and 5mm or less. In addition, it is preferable that the high-density portions are disposed at both ends in the width direction of the water-absorbent nonwoven fabric, and in this case, the dimension in the width direction of the high-density portions located at both ends in the width direction is preferably 3mm or more and 20mm or less.

In the present invention, it is preferable that the water-absorbent fibers located in the high-density portion have an orientation along the longitudinal direction, and the water-absorbent fibers located in the low-density portion have an orientation lower than that of the fibers located in the high-density portion. This makes it easy for the body fluid to diffuse in the longitudinal direction in the high-density portion where the density of the water-absorbent fibers is high.

(center sheet part and outer sheet part)

In the present embodiment, the 1 st core wrap sheet portion 24 includes a center sheet portion 22 disposed at a position close to the center in the width direction W and a pair of outer sheet portions 23 disposed at both outer sides in the width direction W, and both end portions in the width direction W of the center sheet portion 22 overlap with the end portions in the width direction W of the center sheet portion 22 of the pair of outer sheet portions 23 in the thickness direction T and overlap with a pair of overlapping portions 27 extending in the longitudinal direction L. By having the above-described structure for the 1 st core wrap sheet portion 24, the fiber density of the water-absorbent fibers in the pair of overlapping portions 27 can be further increased, and the body fluid can be more easily diffused in the longitudinal direction L in the pair of overlapping portions 27. This provides the absorbent body 17 with excellent repeated diffusion of body fluid. In the present embodiment, the center sheet portion 22 is configured as one sheet, and the 2 nd core wrap sheet portion 25 and the pair of outer sheet portions 23 are integrated with each other to be configured as another sheet.

As shown in fig. 3, in the present embodiment, in each overlapping portion 27 of the pair of overlapping portions 27, the pair of outer sheet portions 23 are respectively disposed on the 1 st surface 34 side of the center sheet portion 22, and the edge portions 31 of the pair of outer sheet portions 23 on the center sheet portion 22 side are separated from the center sheet portion 22. With such a configuration, when the intermediate portion C in the width direction of the laminated absorbent core 21 absorbs bodily fluids and swells, the edge portion 31 of the outer sheet portion 23 overlapping the center sheet portion 22 floats from the surface of the center sheet portion 22 due to the inclination of the 1 st surface 34 of the absorbent body 17, and the edge portion 31 of the outer sheet portion 23 can function as a leakage preventing wall.

In the present invention, the "outer sheet portion" and the "central sheet portion" are included in the 1 st core wrap sheet portion, but preferably, the outer sheet portion and the central sheet portion constitute at least a part of different core wrap sheets separated from each other. In the present invention, the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion may be formed as separate single sheets, and the 1 st core wrap sheet portion and the 2 nd core wrap sheet portion may be joined along the longitudinal direction at both widthwise ends.

In the absorbent body 17 of the present embodiment, the dimension in the width direction W of the 1 st absorbent core layer 18 is smaller than the dimension in the width direction W of the 2 nd absorbent core layer 20, and the pair of overlapping portions 27 are disposed at both width direction end portions E. With such a configuration, the superabsorbent polymer derived from the 1 st absorbent core layer 18 is not present at the portion where the pair of superposed portions 27 are present, and therefore, the bodily fluid easily spreads in the longitudinal direction L in the pair of superposed portions 27 and permeates into the 2 nd absorbent core layer 20, and the absorbent body 17 is excellent in repeated absorbency of bodily fluid.

In the present embodiment, the high-density portions 32 are disposed at both ends in the width direction W of the central panel portion 22, and the high-density portions 32 are disposed at both ends in the width direction W of the panel including the outer panel portion 23. With such a configuration, the fiber density of the water-absorbent fibers in the pair of superposed sections 27 is increased, the liquid permeability along the longitudinal direction L is further improved, the liquid diffusibility in the pair of superposed sections 27 can be further improved, and the body fluid repeating absorbability in the absorbent body 17 can be improved.

As shown in fig. 3, in the present embodiment, the central sheet portion 22 is formed as one sheet, and the outer sheet portion 23 is formed as one sheet integrally with the 2 nd core wrap sheet portion 25. Thus, in the present embodiment, the sheet corresponding to the central sheet portion 22 and the sheet constituted by the outer sheet portion 23 and the 2 nd core wrap sheet portion 25 form a pair of overlapping portions 27 extending in the longitudinal direction L. However, the core wrap sheet of the present invention is not limited to such a structure.

(2 nd core cladding sheet part)

The absorber 17 of the present embodiment has the 2 nd core wrap sheet portion 25 located closer to the 2 nd surface 35 than the thickness direction center surface Tc of the absorber 17. In the present embodiment, the nonwoven fabric constituting the 2 nd core wrap sheet part 25 is composed of a water-absorbent nonwoven fabric similarly to the 1 st core wrap sheet part 24, and both the 1 st core wrap sheet part 24 and the 2 nd core wrap sheet part 25 are composed of a water-absorbent nonwoven fabric, but the 2 nd core wrap sheet part of the present invention is not limited to the embodiment having the water-absorbent nonwoven fabric.

(intermediate joint part)

As shown in fig. 2, in the present embodiment, the absorber 17 includes an intermediate joining section 30 in which an intermediate layer 19 and a 2 nd core wrap sheet portion 25, which will be described later, are joined together at a widthwise intermediate section C. This provides the absorbent body 17 with excellent shape retention properties in dry and wet states. However, in the present invention, the intermediate joint portion may be formed by joining the first core wrap sheet and the intermediate layer.

[ laminated absorbent core ]

The laminated absorbent core 21 included in the absorbent body 17 of the present embodiment is formed by laminating the 1 st absorbent core layer 18, the intermediate layer 19, and the 2 nd absorbent core layer 20 in this order with an adhesive in between the 1 st absorbent core layer 18, the intermediate layer 19, and the 2 nd absorbent core layer 20. In the bookIn the embodiment, the laminated absorbent core 21 has a substantially rectangular planar shape having a dimension in the longitudinal direction L longer than a dimension in the width direction W and a substantially rectangular parallelepiped shape having a constant thickness, but the shape of the laminated absorbent core of the present invention is not limited to such a shape, and any planar shape may be adopted within a range not impairing the functions of the laminated absorbent core for absorbing and retaining liquid. As described later, the 1 st and 2 nd absorbent core layers included in the laminated absorbent core of the present invention contain a super absorbent polymer, and preferably contain pulp fibers as needed. The total superabsorbent polymer of the absorbent body of the present invention preferably has a basis weight of 50g/m²Above and 500g/m²Hereinafter, the basis weight of the pulp fiber is preferably 0g/m²Above and 1000g/m²The following. In addition, the ratio of the weight per unit area of the super absorbent polymer contained in the entire absorbent body of the present invention to the weight per unit area of the pulp fibers is preferably 1: 6-6: 0. in the present invention, an adhesive used for forming the laminated absorbent core as needed may be, for example, a hot melt adhesive. The absorbent body of the present invention is not necessarily limited to the form requiring an adhesive for forming the laminated absorbent core.

(1 st absorbent core layer)

The 1 st absorbent core layer 18 included in the absorbent body 17 of the present embodiment contains a super absorbent polymer carried by an adhesive, but the 1 st absorbent core layer 18 is sandwiched between the intermediate layer 19 and the 1 st core covering sheet portion 24 in the absorbent body 17. In the 1 st absorbent core layer 18 included in the absorbent body 17 of the present embodiment, the super absorbent polymer is arranged substantially uniformly in the planar direction. In the present invention, the superabsorbent polymer of the 1 st absorbent core layer preferably has a weight per unit area of 25g/m²Above and 250g/m²The following. By setting the weight per unit area of the super absorbent polymer within the above range, the absorbent body of the present invention can sufficiently absorb body fluid in excrement and can suppress the occurrence of blocking of the swollen super absorbent polymer to some extent. In the present invention, the 1 st absorbent core layer may also have pulp fibers, in which case the pulp fibersThe weight per unit area is preferably more than 0g/m²And 500g/m²The following. By including pulp fibers in the first absorbent core layer 1, the absorption rate of the absorbent body can be increased, and when pulp fibers are not included, the absorbent body can be configured to be thin. The ratio of the weight per unit area of the superabsorbent polymer of the 1 st absorbent core layer to the weight per unit area of the pulp fibers is preferably 1: 6-6: 0.

in the absorbent body 17 of the present embodiment, the dimension in the width direction W of the 1 st absorbent core layer 18 is smaller than the dimension in the width direction W of the 2 nd absorbent core layer 20 described later over the entire length in the longitudinal direction L. Here, the 1 st absorbent core layer 18 is disposed so that the center line of the 1 st absorbent core layer 18 in the width direction W substantially overlaps the center line of the absorbent body 17 in the width direction W, and both ends of the 1 st absorbent core layer 18 in the width direction W are located closer to the center of the width direction W than each end of the 2 nd absorbent core layer 20 in the width direction W. In the present embodiment, by adopting such a configuration, even when the body fluid is difficult to be absorbed by the 1 st absorbent core layer 18, the body fluid can reach the surface of the 2 nd absorbent core layer 20 having a wide width along the width direction W on the surface of the 1 st absorbent core layer 18. That is, the body fluid which is not absorbed by the 1 st absorbent core layer 18 can be absorbed by the 2 nd absorbent core layer 20, and the absorbent body 17 can absorb the discharged body fluid even when the body fluid is discharged repeatedly, and thus the body fluid repeated absorbability is excellent. As described above, in the present embodiment, the joint portions 29 are provided at both the ends E in the width direction, but since the superabsorbent polymers derived from the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20 are not present at the positions where the joint portions 29 are located, the mechanical strength of the joint portions 29 is less likely to be impaired by swelling accompanied by water absorption of the superabsorbent polymers, and the absorbent body 17 is excellent in shape retention in the wet state.

In the present invention, "the dimension in the width direction of the 1 st absorbent core layer" and "the dimension in the width direction of the 2 nd absorbent core layer" are defined as dimensions that mean the maximum length of the region of the 1 st absorbent core layer and the 2 nd absorbent core layer sandwiched by the outermost edges in the width direction. In the present invention, the dimension in the width direction of the 1 st absorbent core layer may be larger than the dimension in the width direction of the 2 nd absorbent core layer, or may be the same as the dimension in the width direction of the 2 nd absorbent core layer. Also, in the present invention, "the dimension in the longitudinal direction of the 1 st absorbent core layer" and "the dimension in the longitudinal direction of the 2 nd absorbent core layer" mean the maximum length of the region of the 1 st absorbent core layer and the 2 nd absorbent core layer sandwiched by the outermost edges in the longitudinal direction. In the present invention, the dimension in the longitudinal direction of the 1 st absorbent core layer may be larger than the dimension in the longitudinal direction of the 2 nd absorbent core layer, may be smaller than the dimension in the longitudinal direction of the 2 nd absorbent core layer, or may be the same as the dimension in the longitudinal direction of the 2 nd absorbent core layer.

(super absorbent Polymer)

The super absorbent polymer included in the absorbent body of the present invention is intended to absorb and retain liquid in excrement in the absorbent body, and the type thereof is not limited within a range that can achieve the purpose. In the present invention, more specifically, examples of the super absorbent polymer include polyaspartic acid salt polymers, sodium polyacrylate polymers, isobutylene-anhydrous maleic acid copolymers, starch-acrylic acid graft copolymers, acrylic acid-vinyl alcohol copolymers, and the like.

In the present invention, among the above-mentioned polymers and copolymers, a super absorbent polymer which is a polymer or a granulated product of the copolymer produced by reversed-phase suspension polymerization is preferably used. The super absorbent polymer as the polymer or copolymer particles produced by inverse suspension polymerization means polymer or copolymer particles obtained by polymerizing a composition containing a polymerizable monomer as a water-in-oil emulsion in the presence of a surfactant or an emulsifier. Since the surface area of the granulated highly absorbent polymer is larger than the surface area of a truly spherical highly absorbent polymer having the same volume, the specific surface area of the whole granulated highly absorbent polymer becomes large, and the absorption rate of the highly absorbent polymer becomes high. Examples of such a super absorbent polymer include those obtained by the production method described in Japanese patent application laid-open No. 57-094011.

(intermediate layer)

As shown in fig. 2, the laminated absorbent core 21 of the absorbent body 17 of the present embodiment has an intermediate layer 19 between the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20, and the intermediate layer 19 is a thermally fused nonwoven fabric in which a plurality of thermoplastic synthetic fibers are fused. In the present embodiment, since the characteristics of the intermediate layer 19 with respect to the load are less likely to change when the intermediate layer 19 is dry or wet, the intermediate layer 19 is less likely to stretch when wet, and the intermediate layer 19 is less likely to collapse even when the load is applied by the water absorption and expansion of the super absorbent polymers of the 1 st absorbent core layer 18 and the 2 nd absorbent core layer 20, as shown in fig. 3. Therefore, in the absorbent body 17 of the present embodiment, even under the condition where the super absorbent polymer swells, the intermediate layer 19 allows the body fluid to easily penetrate in the longitudinal direction L and the width direction W, and is excellent in liquid permeability and less likely to impair the diffusibility of the body fluid, so that the contact area between the absorbent body 17 and the body fluid is increased, and the body fluid repeated absorbability of the absorbent body 17 is excellent.

In the present embodiment, since the intermediate layer 19 is required to have relatively strong physical strength, three-dimensional irregularities are not formed in the intermediate layer 19 by gear processing and embossing, which will be described later. By providing the intermediate layer 19 as a member that is not subjected to gear machining or embossing, resistance to external loads such as tensile stress can be improved. However, in the present invention, when the elongation in the wet tensile test is in the range of 90% to 110% of the elongation in the dry tensile test and the tensile strength in the wet tensile test is in the range of 90% to 110% of the tensile strength in the dry tensile test, the unevenness may be formed in the intermediate layer, and the apparent bulk of the intermediate layer may be improved or the holding performance of the super absorbent polymer may be improved.

In the present invention, the elongation in the wet tensile test of the heat-fusible nonwoven fabric constituting the intermediate layer is in the range of 90% to 110% of the elongation in the dry tensile test, and the tensile strength in the wet tensile test is in the range of 90% to 110% of the tensile strength in the dry tensile test. In the present invention, the heat-fusible nonwoven fabric is preferably a through-air nonwoven fabric made of thermoplastic synthetic fibers. It is also preferable to subject the heat-fused nonwoven fabric to hydrophilization treatment as necessary. Since the through-air nonwoven fabric is bulky and has excellent cushioning properties, the liquid permeability of the intermediate layer is not easily impaired even when the 1 st and 2 nd absorbent core layers swell, and the absorbent body of the present invention has excellent repeated absorption of body fluid.

In the present invention, as the thermoplastic synthetic fibers constituting the above-described through-air nonwoven fabric, it is preferable to use sheath-core conjugate fibers using a thermoplastic resin as at least a sheath component constituting the fiber surface. By using a thermoplastic resin as the sheath component constituting the fiber surface, the fiber exhibits thermal fusion characteristics, and therefore the resin component used as the core component can be appropriately selected in accordance with the desired physical properties of the intermediate layer. For example, by using a composite fiber in which a resin component having relatively high strength is used as a core component that does not constitute the fiber surface as the sheath-core composite fiber, an intermediate layer having more stable resistance to tensile stress and the like can be provided. Examples of the resin that can be used as the core component and the sheath component include polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, and ionomer resin; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polylactic acid; polyamides such as nylon and the like are appropriately selected and used in combination. In the present invention, for the purpose of achieving both heat-sealing properties and tensile strength, a polyolefin resin such as polyethylene or polypropylene is preferably used as the sheath component, and the above-mentioned polyolefin resin or a polyester resin such as polyethylene terephthalate is preferably used as the core component.

The maximum elongation in the wet tensile test of the heat-fusible nonwoven fabric of the present invention is preferably 20% to 150% in the CD direction, the 30% tensile strength in the CD direction is preferably 0.3N/25mm to 6N/25mm, and the maximum tensile strength in the CD direction is preferably 5N/25mm to 30N/25 mm. The maximum elongation in the dry tensile test of the heat-fusible nonwoven fabric of the present invention is preferably 20% to 150% in the CD direction, the 30% tensile strength in the CD direction is preferably 0.3N/25mm to 6N/25mm, and the maximum tensile strength in the CD direction is preferably 5N/25mm to 30N/25 mm. By setting the elongation and tensile strength of the heat-fused nonwoven fabric within the above ranges, the absorbent body is excellent in shape retention when wet and repeated absorption of body fluid.

In the present invention, the weight per unit area of the intermediate layer is preferably 9g/m²Above and 100g/m²Hereinafter, it is more preferably 12g/m²Above and 60g/m²The following. The thickness of the intermediate layer is preferably 0.1mm or more and 5mm or less, and more preferably 0.15mm or more and 3mm or less. The intermediate layer preferably has a stiffness measured by a cantilever method, which will be described later, of 60mm to 160m in the MD direction. In the present invention, by setting the basis weight, thickness and stiffness of the intermediate layer within the above ranges, the absorbent body is excellent in shape retention properties when wet and repeated absorption properties of body fluids.

(No. 2 absorbent core layer)

The laminated absorbent core 21 included in the absorbent body 17 of the present embodiment has a 2 nd absorbent core layer 20 in which a certain amount of superabsorbent polymer is carried by an adhesive, and the 2 nd absorbent core layer 20 is sandwiched between the intermediate layer 19 and the 2 nd core wrap sheet portion 25, but the structure of the 2 nd absorbent core layer 20 is the same as that of the 1 st absorbent core layer 18 except for the structure relating to the superabsorbent polymer nonexistence region 28 described below. In the present invention, the weight per unit area of the superabsorbent polymer and the weight per unit area of the pulp fiber in the 2 nd absorbent core layer may be the same as the weight per unit area of the superabsorbent polymer and the weight per unit area of the pulp fiber in the 1 st absorbent core layer, may be larger than the weight per unit area of the superabsorbent polymer and the weight per unit area of the pulp fiber in the 1 st absorbent core layer, or may be smaller than the weight per unit area of the superabsorbent polymer and the weight per unit area of the pulp fiber in the 1 st absorbent core layer.

(region where superabsorbent polymer does not exist)

As shown in fig. 2, in the present embodiment, the 2 nd absorbent core layer 20 includes two high absorbent polymer non-existing regions 28 which are provided extending in the longitudinal direction L and in which no high absorbent polymer exists in the thickness direction T from one end portion to the other end portion thereof. Here, the super absorbent polymer swells by absorbing water, and tends to be difficult to transmit liquid due to blocking. In the present embodiment, the 2 nd absorbent core layer 20 includes the high absorbent polymer nonexistent region 28, and the 2 nd absorbent core layer 20 is present on the garment-side surface side, so the absorbent body 17 easily absorbs body fluid that has penetrated into the absorbent body 17 and has accumulated in the portion of the absorbent body 17 close to the backsheet 5. In the present invention, the superabsorbent polymer-free region may be present in the 1 st absorbent core layer, and the 2 nd absorbent core layer may be present on the skin-side surface. In the case described above, that is, in the case where the superabsorbent polymer nonexisting region is located on the skin side surface side relative to the intermediate layer, the body fluid can be diffused in the longitudinal direction in view of the presence of the superabsorbent polymer nonexistent region, and therefore the diffused body fluid easily permeates into the absorbent body, and the permeation of the body fluid from the skin side surface toward the clothing side surface is promoted.

In view of maintaining the absorption performance of the absorbent body and effectively preventing blocking, the number of superabsorbent polymer nonexistent regions of at least one of the 1 st and 2 nd absorbent core layers of the present invention is preferably 1 or more and 4 or less, and preferably two or 3, in the full width of the at least one absorbent core layer in the width direction. In the case where 3 or more regions where superabsorbent polymer is not present are present in the 1 st or 2 nd absorbent core layer, the regions where superabsorbent polymer is not present are preferably provided at equal intervals in the 1 st or 2 nd absorbent core layer, and the width of the regions where superabsorbent polymer is not present is preferably 5mm or more and 60mm or less.

In the present invention, when the superabsorbent polymer nonexistent regions are provided in both the 1 st absorbent core layer and the 2 nd absorbent core layer, the number of superabsorbent polymer nonexistent regions of the 1 st absorbent core layer may be at least greater than the number of superabsorbent polymers of the 2 nd absorbent core layer, or may be the same as the number of superabsorbent polymers of the 2 nd absorbent core layer. Further, the region of the first absorbent core layer where the super absorbent polymer is not present and the region of the second absorbent core layer where the super absorbent polymer is not present may overlap with each other in the width direction or may be different from each other.

In the present invention, in the case where a region where a super absorbent polymer does not exist exists in at least one of the 1 st and 2 nd absorbent core layers, the width-directional dimension of the at least one absorbent core layer means the width-directional dimension of a region including the region where the super absorbent polymer does not exist.

In the present embodiment, the intermediate bonded portion 30 is formed by bonding the 2 nd core covering sheet portion 25 and the intermediate layer 19, the high absorbent polymer nonexistence region 28 exists in the 2 nd absorbent core layer 20, and the high absorbent polymer nonexistence region 28 and the intermediate bonded portion 30 overlap in the thickness direction T. In the present invention, in the case where the intermediate joint portion is provided, one of the 1 st and 2 nd absorbent core layers which is in contact with the 1 st or 2 nd core wrap sheet portions constituting the intermediate joint portion includes a high-absorbent polymer nonexistent region, and the intermediate joint portion overlaps with the high-absorbent polymer nonexistent region in the thickness direction. For example, in the case where the 1 st core wrap sheet portion and the intermediate layer are joined to form the intermediate joint portion, the high absorbent polymer non-existing region exists in the 1 st absorbent core layer, and in the case where the 2 nd core wrap sheet portion and the intermediate layer are joined to form the intermediate joint portion, the high absorbent polymer non-existing region exists in the 2 nd absorbent core layer. In the present invention, since the intermediate bonded portion overlaps the superabsorbent polymer nonexistent region in the thickness direction, the intermediate bonded portion maintains the bonded structure even when the superabsorbent polymer swells, and the absorbent body has excellent shape retention properties in the wet state.

< method for producing absorbent body >

In the production of the absorbent body of the present invention, the production can be basically performed according to the conventional production method of the absorbent body.

First, a hot melt adhesive is applied to the continuous sheet for the core wrap sheet of the lower layer while moving the continuous sheet for the core wrap sheet of the lower layer in the longitudinal direction L. Next, the superabsorbent polymer is dispersed from the superabsorbent polymer supply device along the longitudinal direction L in both end portions and a central portion in the width direction W of the continuous sheet for a core wrap sheet of the lower layer to which the hot melt adhesive is applied. Next, a continuous sheet of the intermediate layer 19 coated on both sides with hot melt adhesive is laminated on the underlying superabsorbent polymer for the core wrap sheet. Next, while moving the laminate in the longitudinal direction L, the superabsorbent polymer is dispersed from another superabsorbent polymer supplying device along the longitudinal direction L on both end portions and a central portion in the width direction W of the continuous sheet for the intermediate layer 19 to which the hot melt adhesive is applied. Next, the continuous sheet for the core wrap sheet of the upper layer to which the hot melt adhesive is applied is laminated on the super absorbent polymer on the continuous sheet for the core wrap sheet of the lower layer so that the hot melt adhesive is on the super absorbent polymer side. Then, after both side portions in the width direction W of the continuous sheet for the core wrap sheet of the lower layer are folded back onto the continuous sheet for the core wrap sheet of the upper layer, the laminate is pressed by a pair of press rolls to adjust the thickness, thereby forming the absorbent body 17.

In the present invention, the water-absorbent nonwoven fabric preferably includes a high-density portion and a low-density portion, and the high-density portion and the low-density portion are preferably formed by subjecting a nonwoven fabric formed by hydroentanglement to gear processing. The gear processing is performed by loading the original roll sheet between shaping devices provided with a pair of upper and lower stretching rollers to be described later and stretching the original roll sheet; the pair of upper and lower stretching rolls have a plurality of ridges provided in parallel with each other at a constant interval in the roll width direction along the outer peripheral surface and grooves between adjacent ridges, and the ridges of one stretching roll are engaged with the grooves of the other stretching roll. Here, since the portion between the two portions fixed adjacent to each other is extended in a state where the portion sandwiched between the top portion of the ridge and the bottom portion of the groove is fixed, the portion where the top portion of the ridge and the bottom portion of the groove are fixed becomes the high-density portion, and the portion sandwiched between the adjacent high-density portions becomes the low-density portion. In addition, in general, when a nonwoven fabric having high stiffness is subjected to gear processing, unevenness may remain on the surface of the nonwoven fabric. In the present invention, the stiffness of the core wrap sheet can be adjusted by adjusting the basis weight and thickness of the nonwoven fabric constituting the core wrap sheet, the material of the water-absorbent fibers, and the like, so that the core wrap sheet is flat even when gear processing is performed.

In addition, in the case of manufacturing the disposable diaper 1 using the absorber 17 of the present embodiment, the 1 st surface 34 is disposed on the skin-side surface, the 2 nd surface 35 is disposed on the garment-side surface, and the 1 st core wrap sheet portion 24 described above is disposed between the absorbent core 21 and the top sheet 3. However, the absorbent article including the absorbent body of the present invention may be configured such that the 1 st surface of the absorbent body is disposed on the clothing side surface and the 2 nd surface is disposed on the skin side surface, and the 1 st core wrap sheet may be disposed between the absorbent core and the top sheet or between the absorbent core and the back sheet.