Absorbent composites and absorbent articles

Abstract

To provide an absorbent composite having excellent absorption performance and fitting property, and absorbent article including the absorbent composite.SOLUTION: An absorbent composite 1 includes a composite sheet 1A in which a superabsorbent polymer is uniformly arranged between two identical or different liquid permeable sheets 2 and 3 in a plane direction. The composite sheet 1A is folded back to a same surface side along a pair of side edges 1S along one direction 1X in the absorbent composite, so as to form a pair of multilayer parts 7 in which composite sheets 1A formed by the folding-back face to each other. Each of the pair of multilayer parts 7 has joint parts 8 in which facing surfaces of the composites 1A are joined together with an adhesive, and a plurality of side slits 9 are formed in side areas 1L along the side edges 1S so as to extend from the side edge 1S in a direction 1Y crossing the one direction. An absorbent article includes the absorbent composite 1 as an absorber.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to absorbent composites and absorbent articles. [Background technology]

[0002] Absorbent articles such as disposable diapers and sanitary napkins include an absorbent body that absorbs and retains bodily waste such as urine and menstrual blood. In recent years, sheet-like absorbent bodies containing absorbent polymers and absorbent articles including such absorbent bodies have been developed with the aim of providing sufficient absorption performance while improving comfort when worn.

[0003] For example, Patent Document 1 describes an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a sheet-like absorbent body containing a superabsorbent polymer disposed between the top sheet and the back sheet, the absorbent body being folded in a C shape with the napped surface facing outward, and the proportion of superabsorbent polymer in the folded portion being lower than the proportion of superabsorbent polymer in the unfolded portion. The document also describes that by folding the absorbent body in a C shape, the central portion of the absorbent body is not affected by the expansion of the superabsorbent polymer even after absorbing bodily waste, and therefore the absorbent performance is good.

[0004] Patent Document 2 describes an absorbent article that includes a top sheet, a back sheet, and an absorbent body containing superabsorbent polymer particles and positioned between the top sheet and the back sheet, and the sides of the absorbent layer contained in the absorbent body are divided into a plurality of portions called winglets. The document also describes that when the absorbent article is worn, the gaps between adjacent winglets decrease, increasing the flexibility of the sides of the absorbent layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-7719 [Patent Document 2] Special Publication No. 2018-508264 Summary of the Invention [Problem to be solved by the invention]

[0006] The absorbent article described in Patent Document 1 has a C-folded absorbent body, which provides some absorption performance in the overlapping areas of the absorbent body. However, after absorbing excrement, differences in thickness occur in the absorbent body due to differences in the proportion of superabsorbent polymer present, leaving room for improvement in terms of wearing comfort.

[0007] The absorbent article described in Patent Document 2 has slits formed on the sides of the absorbent body, which is thought to improve wearing comfort to some extent, but has not been fully investigated in terms of improving absorption performance.

[0008] Therefore, the present invention relates to an absorbent composite material having excellent absorption performance and wearing comfort, and an absorbent article including the absorbent body. [Means for solving the problem]

[0009] The present invention relates to an absorbent composite material comprising a composite sheet in which a superabsorbent polymer is uniformly distributed in the planar direction between two identical or different liquid-permeable sheets. It is preferable that the composite sheet is folded back along a pair of side edges along one direction of the absorbent composite material to the same side, and that the folding back forms a pair of multilayer sections in which the composite sheets face each other. It is preferable that each of the pair of multilayer sections has a joint where the opposing surfaces of the composite sheets are joined with an adhesive, and that multiple side slits are formed in the side areas along the side edges, each extending from the side edges in a direction intersecting the one direction.

[0010] The present invention also relates to an absorbent article comprising an absorbent body, a topsheet disposed on the skin-facing side of the absorbent body, and a backsheet disposed on the non-skin-facing side of the absorbent body. The absorbent composite material is preferably used in the absorbent body. [Effects of the Invention]

[0011] According to the present invention, there are provided an absorbent composite having excellent absorption performance and a comfortable fit, and an absorbent article comprising the absorbent composite. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a plan view schematically showing one embodiment of the absorbent composite of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the absorbent composite material shown in FIG. 1 taken along line II. [Figure 3] FIG. 3 is a cross-sectional perspective view showing an example of a cross section taken along line II-II in the absorbent composite material shown in FIG. 1 in a used state. [Figure 4] FIG. 4 is a cross-sectional view schematically showing one embodiment of the absorbent article of the present invention. [Figure 5] 5(a) and 5(b) are plan views schematically showing another embodiment of the absorbent composite of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on its preferred embodiments with reference to the drawings. Figures 1 and 2 show an embodiment of the absorbent composite material of the present invention. The absorbent composite 1 shown in FIGS. 1 and 2 comprises a composite sheet 1A including two liquid-permeable sheets 2 and 3 and a superabsorbent polymer 4 disposed between the two liquid-permeable sheets 2 and 3. In the composite sheet 1A, two liquid-permeable sheets 2 and 3 are arranged opposite each other, with a superabsorbent polymer 4 sandwiched between the opposing sheets 2 and 3. The two liquid-permeable sheets 2 and 3 and the superabsorbent polymer 4 are integrated into a sheet-like form. The two liquid-permeable sheets 2 and 3 are flexible, and the composite sheet 1A is also flexible.

[0014] The two liquid-permeable sheets 2, 3 may be either the same or different. "The same sheet" means a sheet made of the same constituent material and manufactured by the same method. "The same constituent material" means that when the liquid-permeable sheet contains multiple constituent materials, for example, when the liquid-permeable sheet is a fiber sheet formed from a fiber material and the constituent fibers contain multiple fibers with different fiber diameters, fiber lengths, or constituent resins, the blending ratios of the multiple constituent materials are also the same. On the other hand, "different sheets" means sheets other than the same sheet. For example, when the liquid-permeable sheet is a fiber sheet formed from a fiber material, the sheets are sheets in which at least one of the constituent fibers and the manufacturing method is different. The superabsorbent polymer 4 is uniformly distributed in the planar direction of the composite sheet 1A. "Uniformly distributed in the planar direction" means that the superabsorbent polymer 4 is uniformly distributed when viewed along the surfaces located at both ends in the thickness direction of the composite sheet 1A, and there are no regions in the composite sheet 1A where the amount of superabsorbent polymer 4 present is intentionally reduced compared to other regions of the composite sheet 1A. Although no other components are present on the outer surfaces of the liquid-permeable sheets 2, 3 shown in Figures 1 and 2, as will be described later, this does not prevent other components, such as components of an absorbent article, from being placed on the outer surfaces of the liquid-permeable sheets 2, 3.

[0015] In this embodiment, the composite sheet 1A has, as liquid-permeable sheets, a first sheet 2 which is a liquid-permeable sheet located on the surface side of the absorbent composite 1 when it is made into the absorbent composite 1, and a second sheet 3 which is a liquid-permeable sheet located on the inner side of the absorbent composite 1. The first sheet 2 and the second sheet 3 may be of the same type or different types. Sheets of the same type include the "same sheet" described above. The first sheet 2 has superabsorbent polymer 4 uniformly distributed on one surface thereof. The superabsorbent polymer 4 is bonded to the first sheet 2 with adhesive 6A. The superabsorbent polymer 4 on the side opposite to the surface facing the first sheet 2 is bonded to the second sheet 3 with adhesive 6B. By bonding the superabsorbent polymer 4 with adhesives 6A and 6B, the superabsorbent polymer 4 is less likely to move excessively or fall off even when external stress is applied to the absorbent composite 1.

[0016] The constituent fibers of the first sheet 2 and the second sheet 3 can each independently be various fibers such as natural pulp such as wood pulp, cotton, and hemp; modified pulp such as mercerized pulp and chemically crosslinked pulp; synthetic fibers containing at least one of synthetic resins such as polyolefins such as polyethylene and polypropylene, and polyesters such as polyethylene terephthalate; recycled fibers such as rayon, cupra, and Tencel; or fibers obtained by subjecting these fibers to a hydrophilic or hydrophobic treatment.

[0017] The first sheet 2 and the second sheet 3 are each independently in the form of paper, woven fabric, or nonwoven fabric. The first sheet 2 and the second sheet 3 may each independently be single-layer or multi-layer. The first sheet 2 and the second sheet 3 may be composed of only one fiber aggregate (whether single-layer or multi-layer), or may have a multi-ply laminate structure in which the first fiber aggregate is layered with a fiber aggregate other than the first fiber aggregate or with another sheet material other than the fiber aggregate. From the viewpoint of improving the absorption performance of the absorbent composite 1, the first sheet 2 and the second sheet 3 are preferably single-layer sheets.

[0018] In the absorbent composite 1, the composite sheet 1A has a structure in which a pair of side edge portions 1S, 1S along one direction 1X of the absorbent composite 1 are folded back to the same side (see FIG. 2). More specifically, in the flat composite sheet 1A, side regions located outside the positions that would become the side edge portions 1S are folded back to the side consisting of the second sheet 3 so that the composite sheets 1A face each other, as shown in FIG. 2. In this embodiment, this folding is performed over the entire area of ​​the absorbent composite 1 in the longitudinal direction 1X.

[0019] In this embodiment, the one direction 1X is a direction that coincides with the longitudinal direction 1X of the absorbent article that runs along the front-to-back direction of a wearer when the absorbent composite 1 is used as a constituent member of the absorbent article 10 described below, and the orthogonal direction 1Y that is orthogonal to the one direction 1X is a direction that coincides with the lateral direction 1Y that is orthogonal to the longitudinal direction 1X of the absorbent article when the absorbent composite 1 is used as a constituent member of the absorbent article 10. Hereinafter, the one direction 1X and the direction 1Y that is orthogonal to the one direction 1X in the absorbent composite 1 are also referred to as the longitudinal direction 1X and the lateral direction 1Y. It is also preferable that one direction 1X of the absorbent composite 1 is the longitudinal direction or the lateral direction of the absorbent composite 1, which has a longitudinal direction and a lateral direction in a planar view, in relation to the orientation when incorporated into an absorbent article or regardless of the orientation, and it is even more preferable that it is the longitudinal direction as shown in Figure 1.

[0020] By folding back the side regions of the composite sheet 1A, a pair of opposing portions of the composite sheet 1A is formed, as shown in Figure 2. The opposing portions of the composite sheets 1A form the multilayer portion 7. The thickness of the multilayer portion 7 is greater than the thickness of a single composite sheet 1A. The expression "opposing composite sheets 1A" includes both cases where the opposing surfaces of the composite sheets 1A are overlapping in a state of surface contact and cases where there is a gap between the opposing surfaces of the composite sheets 1A; however, from the viewpoint of improving absorbency, it is preferable that the opposing surfaces of the composite sheets 1A are in contact or close to each other.

[0021] In this way, the absorbent composite 1 of the present invention has a multilayer section 7 formed by overlapping composite sheets 1A, and the superabsorbent polymer 4 is arranged in two layers in the multilayer section 7, which further improves the absorption performance of the absorbent composite 1 and absorbent articles using the same compared to when the superabsorbent polymer 4 is arranged in a single layer. From the perspective of improving the overall absorption performance of the absorbent composite 1, it is preferable that such folding be performed over the entire area of ​​the composite sheet 1A in the longitudinal direction 1X.

[0022] In the multilayer section 7 formed by the above-described folding, the folded composite sheets 1A face each other. In this embodiment, the second sheets 3 of the composite sheets 1A face each other. Each pair of multilayer sections 7 in the absorbent composite 1 has a joining section 8 where the opposing surfaces of the composite sheets 1A, i.e., the opposing surfaces of the second sheets 3, are joined with an adhesive 6C. In the present invention, one multilayer portion 7 and the other multilayer portion 7 of a pair of multilayer portions 7 may be spaced apart from each other in an orthogonal direction 1Y that is orthogonal to one direction 1X, or may be continuous in the orthogonal direction 1Y. Similarly, the joint portion 8 of one multilayer portion 7 and the joint portion 8 of the other multilayer portion 7 may be spaced apart from each other in the orthogonal direction 1Y, or may be continuous. When one multilayer portion 7 and the other multilayer portion 7 are continuous in the orthogonal direction 1Y, they are divided into one multilayer portion 7 and the other multilayer portion 7 at the center position in the orthogonal direction 1Y, as shown in Figure 2. In this embodiment, one multilayer section 7 and the other multilayer section 7 are continuous in the width direction 1Y, thereby improving the absorption performance throughout the entire width direction 1Y of the absorbent composite 1. While Fig. 2 shows a configuration in which three layers of composite sheet 1A are overlapped in the central portion in the width direction 1Y, a configuration in which the entire width direction 1Y is a multilayer section 7 in which two layers of composite sheet 1A are overlapped, or a configuration in which only portions within a predetermined width from each end in the width direction 1Y are multilayer sections 7 are also preferred.

[0023] In the longitudinal direction 1X of the absorbent composite 1, the joints 8 of the multilayer section 7 are preferably formed at least in the longitudinal central region B of the absorbent composite 1, and more preferably formed extending in the longitudinal direction 1X from the front region A through the longitudinal central region B to the rear region C. The joints 8 of the multilayer section 7 are preferably formed continuously in the longitudinal direction 1X in the longitudinal central region B or the like, but may also be formed intermittently with gaps at predetermined intervals. The front region A, the longitudinal central region B, and the rear region C are the three regions obtained when the absorbent composite 1 is divided into three equal regions along the entire length in the longitudinal direction 1X. Because the pair of multilayer sections 7 of the absorbent composite 1 have joint sections 8, the folded structure of the absorbent composite 1 is less likely to be released even when external pressure is applied to the absorbent composite 1, and the improved absorption performance resulting from the folded structure is maintained.

[0024] From the viewpoint of improving absorption performance, the length in the lateral direction 1Y of each of the pair of multilayer sections 7 is preferably at least 10%, more preferably at least 20%, and even more preferably 40% longer than the total length in the lateral direction 1Y of the absorbent composite 1. There is no particular upper limit, and the total length of the length in the lateral direction 1Y of one multilayer section 7 and the length in the lateral direction 1Y of the other multilayer section 7 is the total length in the lateral direction 1Y of the absorbent composite 1. As shown in FIG. 2, if there is an overlapping portion between one multilayer section 7 and the other multilayer section 7, for example in the center in the lateral direction Y, the length of the overlapping portion on the outside is not included in the total length.

[0025] It is also preferable that the first sheet 2 and the second sheet 3 are directly bonded to one or both ends of the composite sheet 1A, for example, at the overlapping portion between one multilayer section 7 and the other multilayer section 7, and that an area where the superabsorbent polymer 4 is not present is provided.

[0026] It is preferable to use adhesives 6A, 6B, and 6C that are flexible enough to expand in response to the swelling changes that accompany the liquid absorption of the superabsorbent polymer 4. Examples of such raw materials include acrylic adhesives containing one or more vinyl monomer (co)polymers (such as ethylene-vinyl acetate copolymers) including 2-ethylhexyl acrylate, butyl acrylate, ethyl acrylate, cyanoacrylate, vinyl acetate, and methyl methacrylate; silicone adhesives containing polydimethylsiloxane polymers; and rubber-based adhesives such as natural rubber-based adhesives, isoprene-based adhesives containing one or more polyisoprenes, chloroprenes, and styrene-based adhesives containing one or more styrene-butadiene copolymers (SBR), styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene-butadiene-styrene block copolymers (SEBS), and styrene-ethylene-propylene-styrene block copolymers (SEPS). These may be used alone or in combination of two or more.

[0027] The adhesives 6A and 6B disposed on the surfaces of the first sheet 2 and the second sheet 3 facing the superabsorbent polymer 4 and the adhesive 6C forming the joint may be the same or different. The adhesives 6A and 6B used in the composite sheet 1A may also be the same or different.

[0028] From the viewpoints of excellent flexibility and elasticity, maintaining a direct bond between the first sheet 2 and the superabsorbent polymer 4 and between the second sheet 3 and the superabsorbent polymer 4 even after the superabsorbent polymer 4 swells, maintaining the folded structure of the absorbent composite 1, and making it easier to hold the superabsorbent polymer 4 between the first sheet 2 and the second sheet 3, it is preferable to use a rubber-based adhesive as the adhesives 6A, 6B, and 6C, and it is even more preferable to use a styrene-based adhesive among the rubber-based adhesives.

[0029] From the viewpoint of achieving both flexibility of the adhesive and adhesiveness to the first sheet 2 and the second sheet 3, the adhesives 6A and 6B are preferably hot melt adhesives. From the viewpoint of adhesiveness between the second sheets 3 and processability, the adhesive 6C is also preferably a hot melt adhesive. As the hot melt adhesive, various known adhesives can be used. For example, the various adhesives described above can contain a tackifier such as a petroleum resin or a polyterpene resin, a plasticizer such as a paraffin oil, and, if necessary, an antioxidant such as a phenol-based, amine-based, phosphorus-based, or benzimidazole-based.

[0030] The application pattern of each adhesive 6A, 6B, 6C is not particularly limited, and for example, a coating method such as spiral coating, summit coating, or omega coating may be used, which forms uncoated areas of adhesive 6A, 6B, or a method such as spray coating or coater coating, which allows adhesive 6A, 6B, 6C to be continuously applied to the sheet surface, may be used.

[0031] 1 and 3, in a plan view of the absorbent composite 1, a plurality of side slits 9 are formed in the side regions 1L along the side edge portions 1S. Each of the side slits 9 extends from the side edge portion 1S in a direction intersecting the longitudinal direction 1X, more specifically, in a direction perpendicular to the longitudinal direction 1X. The side slits 9 are formed so as to penetrate the multi-layer portion 7. The side slits 9 are not formed by cutting out a portion of the absorbent composite 1, but are formed in the shape of thin lines. By forming the side slits 9 in this manner, flexibility is imparted to the side regions 1L, which are thicker and harder due to the folded structure. This allows the absorbent composite 1, for example, to be used as an absorbent article 10, to have excellent followability to the movement of the wearer, particularly in the crotch area, and improves the wearing comfort.

[0032] In this embodiment, in each of the pair of side regions 1L, the side slits 9 are distributed over the entire area in the longitudinal direction 1X of the absorbent composite 1. More specifically, in each of the front region A, the longitudinal central region B, and the rear region C, a plurality of side slits 9 are formed in each side region 1L. From the viewpoint of improving the wearing comfort, the range in which the side slits 9 are formed in the longitudinal direction 1X of the absorbent composite 1 is preferably 30% or more, more preferably 50% or more, and also preferably 95% or less, more preferably 90% or less, and also preferably 30% or more and 95% or less, more preferably 50% or more and 90% or less, of the total length of the absorbent composite 1. From the same viewpoint, it is preferable that the side slits 9 are formed at least in the longitudinal central region B, and it is preferable that they are formed in the front region A and the rear region C in addition to the longitudinal central region B. From the same viewpoint, the number of side slits 9 per side region 1L is preferably 5 or more, more preferably 10 or more, even more preferably 15 or more, and preferably 50 or less, more preferably 40 or less, even more preferably 30 or less.

[0033] From a similar perspective, for each side region 1L, the spacing between adjacent side slits 9 in the longitudinal direction 1X is preferably 5% or more, more preferably 7% or more, and preferably 15% or less, more preferably 12% or less, and preferably 5% or more and 15% or less, more preferably 7% or more and 12% or less, of the total length of the absorbent composite 1. From the same viewpoint, the length of the side slits 9 in the lateral direction 1Y is preferably 5% or more, more preferably 6% or more, even more preferably 7% or more, and preferably 15% or less, more preferably 13.5% or less, even more preferably 12% or less of the overall width of the absorbent composite 1. The length in the lateral direction 1Y is measured as the distance between one end farther from the side edge 1S and the side edge 1S, along a direction perpendicular to the side edge 1S.

[0034] The absorbent composite 1 according to this embodiment is formed by folding a composite sheet 1A. Each multilayer section 7 has a joint 8 and side slits 9 in the side regions 1L along the longitudinal direction 1X. This allows the folded structure of the composite sheet 1A to be easily maintained, even when external pressure is applied to the side regions 1L, both before and after liquid absorption. This maintains the flexibility and absorbency resulting from this structure, and also allows deformation that curves part or all of the side regions 1L of the absorbent composite 1. This improves the fit to the wearer's skin and the ability to follow the wearer's movements when used as a component of an absorbent article. These effects result in excellent absorption performance and comfort.

[0035] As shown in Fig. 2, each multilayer section 7 in the absorbent composite 1 has a non-bonded region 8S of a predetermined width between the end 7e on the side edge 1S side at the location where the composite sheets 1A face each other and the bonded section 8. The non-bonded region 8S is a region where the opposing surfaces of the composite sheets 1A are not bonded to each other. In the non-bonded region 8S of this embodiment, the opposing surfaces of the composite sheets 1A are not bonded to each other by an adhesive, nor are they bonded to each other by any bonding means other than adhesive, such as heat fusion.

[0036] When the absorbent composite 1 absorbs fluid and the superabsorbent polymer 4 swells, the components of the absorbent composite 1 tend to twist inward in the lateral direction 1Y. Because the absorbent composite 1 has the non-bonded regions 8S, the boundaries between the non-bonded regions 8S and the bonded portions 8 act as twist stoppers. As a result, even if twisting occurs, the spread of twisting to the entire absorbent composite 1 is suppressed, and the improved wearing comfort is maintained even after excretion. From the viewpoint of improving the wearing comfort, the distance from the side edge of the absorbent composite 1 to the innermost position of the non-bonded region 8S in the lateral direction 1Y is preferably 5% or more, more preferably 7% or more, and also preferably 12% or less, more preferably 10% or less, and also preferably 5% or more and 12% or less, more preferably 7% or more and 10% or less, of the total width of the absorbent composite 1.

[0037] When the multi-layer section 7 has a non-bonded region 8S, the innermost end of the side slit 9 in the lateral direction 1Y may be located in the non-bonded region 8S, or may reach the bonded section 8. It is preferable that the innermost end of the side slit 9 be located within the non-bonded region 8S, as this makes it less likely that the adhesive will come into contact with the skin. When the multilayer portion 7 has a non-bonded region 8S, it is preferable that the area in which the side slits 9 are formed and the area in which the non-bonded region 8S are formed overlap at least partially in the longitudinal direction 1X of the absorbent composite 1, and it is preferable that the non-bonded region 8S is formed over the entire area in which the slits 9 are formed.

[0038] In the non-bonded region 8S, a gap may exist between the first sheet 2 and the second sheet 3 positioned opposite each other. On the other hand, from the viewpoint of improving absorbency, it is preferable that the first sheet 2 and the second sheet 3 positioned opposite each other are in contact or at least close to each other. From these viewpoints, the maximum separation distance between the first sheet 2 and the second sheet 3 positioned opposite each other in the non-bonded region 8S is preferably 0% or more, preferably 2% or less, more preferably 1% or less of the total thickness of the absorbent composite 1 in the same thickness direction, and also preferably 0% or more and 2% or less, more preferably 0% or more and 1% or less. The maximum separation distance is measured by cutting the absorbent composite 1 along the transverse direction 1Y before liquid absorption and observing the cross section under no load. The measurement is preferably performed under magnification using a microscope or the like.

[0039] At least one of the first sheet 2 and the second sheet 3 is preferably a nonwoven fabric, and more preferably a nonwoven fabric in which the constituent fibers are entangled. The term "entangled" as used herein refers to a state in which the constituent fibers are sufficiently entangled with each other, and does not include a state in which fiber layers are simply overlapped. By using such a sheet, the flexibility of the absorbent composite 1 is increased and the wearing comfort is improved when the absorbent composite 1 is used in an absorbent article 10.

[0040] From the viewpoint of further improving the wearing comfort, it is preferable that at least one of the first sheet 2 or the second sheet 3, in addition to the above-mentioned configuration, is a fiber sheet that does not have any heat-sealed portions of the constituent fibers, or a nonwoven fabric that has a predetermined proportion or less of heat-sealed portions. Specifically, it is preferable that at least one of the first sheet 2 and the second sheet 3 is a fiber sheet that does not have any thermally fused portions between the constituent fibers. Alternatively, it is also preferable that at least one of the first sheet 2 and the second sheet 3 is a nonwoven fabric that has 30 or less thermally fused portions between the constituent fibers, more preferably 20 or less, and even more preferably 10 or less. By using such a sheet, the flexibility of the absorbent composite 1 is increased, and when the absorbent composite 1 is used in an absorbent article 10, the discomfort caused by the side edge portion 1S of the absorbent composite 1 coming into contact with the wearer is reduced, improving the wearing comfort.

[0041] Examples of fiber sheets that do not have thermally fused portions of the constituent fibers include tissue paper obtained by wet or dry papermaking methods, and spunlace nonwoven fabrics and airlaid nonwoven fabrics, which are made by hydroentangling or using a binder from webs formed by carding or airlaying. Nonwoven fabrics with a predetermined proportion or less of thermally fused portions of the constituent fibers can be easily obtained by using a nonwoven fabric containing two or more types of fibers, including fibers containing high-melting-point components and fibers containing low-melting-point components. Examples of fibers containing high-melting-point components include fibers containing thermoplastic resins such as polyethylene terephthalate (PET). Examples of fibers containing low-melting-point components include fibers containing thermoplastic resins such as polyethylene (PE). Furthermore, thin paper can also be used as the fiber sheet used as one or both of the first sheet 2 and the second sheet 3. Such thin paper can be provided with deodorizing and antibacterial properties. From the viewpoint of providing flexibility to the absorbent composite 1 and improving the wearing comfort when made into an absorbent article, it is preferable to use deodorizing and antibacterial paper as the first sheet 2, and to use spunlace nonwoven fabric as the second sheet 3.

[0042] The number of heat-fused portions of the constituent fibers refers to the number of heat-fused portions present in a single fiber, and is defined in units of "pieces / fiber." The number of heat-sealed portions can be measured by the following method. First, the sheet to be measured is removed from the absorbent composite 1, taking care not to change the thickness of the sheet. If the sheet to be measured is joined to another member with an adhesive, the adhesive is solidified using a cooling means such as cold spray before removal. If the sheet to be measured has superabsorbent polymer 4 attached, the adhesive is similarly solidified using a cold spray or the like before the superabsorbent polymer 4 is removed. Next, the sheet to be measured is cut into 100mm squares to create measurement pieces. The measurement pieces are placed and fixed on the specimen stage of a scanning electron microscope (SEM) with carbon tape placed on it. From the SEM image obtained at 150x magnification, the total number of areas where the intersections of the constituent fibers are fused together is counted. The fused areas are areas where the boundaries between the constituent fibers are unclear. Furthermore, based on the same SEM image, the fiber length of all the constituent fibers shown is measured. This process is performed on five SEM images. Separately, an SEM image magnified 35x is obtained, 50 constituent fibers are extracted, and the arithmetic average fiber length is taken as the fiber length of each constituent fiber. The number of fusion points per constituent fiber can be calculated by dividing the total fusion points within the 140x SEM image by the total fiber length within the 140x SEM image and multiplying this by the length per constituent fiber in the 35x SEM image. These measurements are carried out in an environment with a temperature of 15°C to 35°C and a humidity of 20% RH to 70% RH.

[0043] The absorbent composite 1 of the embodiment shown in Figures 1 to 3 may be used as is. In this case, one absorbent composite 1 may be used alone, or multiple absorbent composites 1 may be stacked or aligned in a plane direction.

[0044] The absorbent composite 1 of the embodiment shown in Figures 1 to 3 can be used as a constituent member of an absorbent article, and is preferably used as an absorbent body of the absorbent article. Examples of absorbent articles include, but are not limited to, disposable diapers, incontinence pads, sanitary napkins, panty liners, etc., and broadly include articles used to absorb liquids discharged from the human body, such as urine, feces, menstrual blood, sweat, etc.

[0045] The absorbent article 10 typically has a longitudinal direction aligned with the front-to-back direction of the wearer and a width direction perpendicular to the longitudinal direction. It comprises an absorbent core, a topsheet disposed on the skin-facing side of the absorbent core, and a backsheet disposed on the non-skin-facing side of the absorbent core. The absorbent article 10 of the present invention can include the above-described absorbent composite 1 as the absorbent core. Examples of the absorbent article 10 include incontinence pads, sanitary napkins, and disposable diapers. When the absorbent composite 1 is used as a component of the absorbent article 10 to improve the liquid absorption of the absorbent article 10, the absorbent composite 1 may be used alone or in a stack of multiple sheets. Alternatively, an absorbent core other than the absorbent composite 1 may be further laminated in addition to the absorbent composite 1. When an absorbent core other than the absorbent composite 1 is laminated on the absorbent composite 1, the other absorbent core is preferably disposed at least in the central region of the absorbent composite 1. Other absorbent bodies include, for example, stacks of hydrophilic fibers such as cellulose, including pulp, and mixed stacks of such hydrophilic fibers and absorbent polymers.

[0046] FIG. 4 shows an example of an absorbent article 10 that uses the absorbent composite 1 as an absorbent body. The top sheet 11 used in the absorbent article 10 is a sheet that constitutes the side that faces the skin of a wearer wearing the absorbent article 10 (hereinafter, this will also be referred to as the "skin-facing side") when the absorbent article 10 is worn in the correct position, and the back sheet 12 is a sheet that constitutes the side that faces away from the skin of a wearer wearing the absorbent article 10 (hereinafter, this will also be referred to as the "non-skin-facing side"). The top sheet 11 and the back sheet 12 used in the absorbent article 10 can be any of those that have been conventionally used in absorbent articles 10, without any particular restrictions. For example, various liquid-permeable nonwoven fabrics and perforated films can be used as the top sheet 11. For example, various liquid-impermeable or water-repellent resin films, laminates of resin films and nonwoven fabrics, etc. can be used as the back sheet 12.

[0047] In addition to the top sheet, back sheet, and absorbent core described above, depending on the specific use of the absorbent article 10, leakage-preventing cuffs extending along the longitudinal direction may be arranged on both longitudinal sides of the skin-facing side. The leakage-preventing cuffs generally have a base end and a free end. The leakage-preventing cuffs have their base end on the skin-facing side of the absorbent article and stand up from the skin-facing side. The leakage-preventing cuffs are made of a liquid-resistant or water-repellent and breathable material. An elastic member made of rubber thread or the like may be arranged in a stretched state at or near the free end of the leakage-preventing cuff. When the pants-type absorbent article is worn, contraction of this elastic member causes the leakage-preventing cuffs to stand up toward the wearer's body, effectively preventing liquid excreted on the top sheet from leaking outward in the width direction of the absorbent article 10.

[0048] When the absorbent composite 1 is used as a component of the absorbent article 10, it is preferable that the absorbent composite 1 be arranged so that the surface opposite to the folded side of the composite sheet 1A faces the skin-facing side of the absorbent article 10 (see FIG. 4). By arranging the absorbent composite 1 in this way, the flat surface faces the skin, which has the effect of reducing the discomfort caused by the unevenness of the fold.

[0049] Figures 5(a) and 5(b) show other embodiments of the absorbent composite 1 of the present invention. Regarding the embodiment of the absorbent composite 1 shown in these figures, the configurations that differ from the absorbent composite 1 shown in Figures 1 to 3 will be mainly described, and the same configurations as those of the absorbent composite 1 will be assigned the same reference numerals and will not be described again. Furthermore, for the configurations that are not specifically described in the embodiments shown in these figures, the description of the absorbent composite 1 shown in Figures 1 to 3 will be applied as appropriate.

[0050] In the embodiment shown in Figure 5(a), in a plan view of the absorbent composite 1, a plurality of intermediate region slits 9A extending in the lateral direction 1Y are formed in an intermediate region located between a pair of side regions 1L, 1L. The intermediate region slits 9A are formed in a staggered pattern across the entire area in the longitudinal direction 1X of the absorbent composite 1. Furthermore, the distance between adjacent side slits 9 in the absorbent composite 1 is narrower than the distance between adjacent intermediate region slits 9A in the longitudinal direction 1X. Forming the intermediate slits 9A in addition to the side slits 9 in the absorbent composite 1 improves the flexibility of the entire absorbent composite 1. As a result, when the absorbent composite 1 is used in an absorbent article 10, the wearing comfort is improved.

[0051] In the embodiment shown in FIG. 5(b), a plurality of intermediate area slits 9A are formed in a V-shape that opens rearward in the vertical direction 1X. The intermediate region slits 9A are formed in a V-shape, which improves the flexibility of the entire absorbent composite 1 and results in a better wearing comfort. Furthermore, the force applied inward in the lateral direction 1Y from the side regions 1L can be dispersed and received by the intermediate region of the absorbent composite 1, which makes the intermediate region less likely to fold and reduce discomfort when worn.

[0052] When providing an intermediate region slit 9A, from the viewpoint of receiving the force applied inward in the horizontal direction 1Y from both side regions 1L while dispersing it in the intermediate region of the absorbent composite 1, the angle θ2 (see Figure 5(b)) of the intermediate region slit 9A with respect to the horizontal direction 1Y perpendicular to the longitudinal direction 1X is preferably less than 45°, more preferably 30° or less, and even more preferably 15° or less, with the lower limit being 0°, and when parallel to the horizontal direction 1Y.

[0053] The angle θ1 of the side slits 9 relative to the direction perpendicular to the longitudinal direction 1X, i.e., the transverse direction 1Y (see FIG. 5(a)), is preferably less than 45°, more preferably 30° or less, and even more preferably 15° or less. The lower limit of the angle θ1 is 0°. When the angle θ1 is 5° or less, including 0°, it is expressed as being parallel to the transverse direction 1Y, and parallel to the transverse direction 1Y is most preferable. By making the angle θ1 less than 45° and forming the side slits 9 in a direction intersecting the longitudinal direction 1X, the effect of reducing the stiffness of the folded-back side regions 1L is more reliably achieved.

[0054] The present invention has been described above based on its preferred embodiments, but the present invention is not limited to the above embodiments and can be modified as appropriate within the scope of the invention. For example, the side slits 9 may be formed only in the longitudinal central region B, or only in the longitudinal central region B and the front region A, or only in the longitudinal central region B and the rear region C. Similarly, the non-bonded region 8S may be formed only in the longitudinal central region B, or only in the longitudinal central region B and the front region A, or only in the longitudinal central region B and the rear region C.

[0055] The intermediate region slits 9A may not be provided, and when the intermediate region slits 9A are provided, the orientation and arrangement pattern thereof may be changed as appropriate. For example, the orientation of the intermediate region slits 9A in the embodiment shown in Figures 5(a) and 5(b) may be changed to a direction extending in the vertical direction 1X, and the arrangement pattern thereof may also be changed as appropriate. [Explanation of symbols]

[0056] 1. Absorbable composites 1A Composite Sheet 2. First sheet (liquid-permeable sheet) 3. Second sheet (liquid-permeable sheet) 4. Superabsorbent polymer 6A Adhesive 6B Adhesive 7 Multi-layer section 8 Joint 6C Adhesive 8S non-bonded area 9 Side slits 9A Mid-range slit 1S side edge 1L Side area 1X vertical (one direction) 1Y Horizontal direction (direction perpendicular to one direction) A front area B Vertical center area C Posterior area 10 Absorbent articles

Claims

1. An absorbent composite material comprising a composite sheet in which a superabsorbent polymer is uniformly arranged in a planar direction between two identical or different liquid-permeable sheets, the composite sheet is folded back along a pair of side edges of the absorbent composite material in one direction to the same side, and a pair of multilayer sections are formed by the folding back of the composite sheets facing each other, Each of the pair of multilayer sections has a joint portion where opposing surfaces of the composite sheets are joined with an adhesive, and a plurality of side slits are formed in side regions along the side edges, each extending from the side edge in a direction intersecting the one direction, An absorbent composite material in which each of the pair of multilayer sections has a non-bonded area of ​​a predetermined width between the end on the side edge side at the location where the composite sheets face each other and the joint, where the opposing surfaces of the composite sheets are not bonded to each other.

2. At least one of the two liquid-permeable sheets is The absorbent composite material according to claim 1, which is a fiber sheet that does not contain any heat-sealed portions of the constituent fibers, or a nonwoven fabric in which the number of heat-sealed portions of the constituent fibers is 30 or less per fiber and the constituent fibers are entangled with each other.

3. 3. The absorbent composite according to claim 1, wherein a middle region slit is formed in the middle region located between the pair of side regions.

4. 4. The absorbent composite according to claim 3, wherein the distance between adjacent side slits in the one direction is narrower than the distance between adjacent intermediate slits in the one direction.

5. 5. The absorbent composite of claim 1, wherein the angle of the side slits relative to the direction perpendicular to the one direction is less than 45 degrees.

6. An absorbent article comprising an absorbent body, a top sheet disposed on the skin-facing side of the absorbent body, and a back sheet disposed on the non-skin-facing side of the absorbent body, An absorbent article, wherein the absorbent composite material according to any one of claims 1 to 5 is used in the absorbent body.

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