Absorber and sanitary material product

Abstract

The present invention addresses the problem of providing an absorber which is flexible and has excellent absorber strength when swollen. The absorber comprises a first nonwoven fabric, a first water-absorbing polymer group, a second nonwoven fabric, a second water-absorbing polymer group, and a third nonwoven fabric in the given order, wherein: the second nonwoven fabric comprises a plurality of through holes; the area of the through hole opening per one of the plurality of through holes is included in the range of 1.5-10.0 mm2; and the number of through holes within a 6.45 cm2 region in each of the two surfaces of the second nonwoven fabric is 10-75.

Description

Absorbent materials and sanitary materials products 【0001】 This invention relates to absorbent materials and sanitary material products. 【0002】 Sanitary materials such as disposable diapers and sanitary napkins have a sheet-like absorbent core, a surface sheet, and a back sheet that absorb and retain watery liquids such as urine and menstrual blood (hereinafter sometimes referred to as "urine, etc."). The absorbent core is sandwiched between the surface sheet and the back sheet, with the surface sheet being permeable to urine, etc., and the back sheet preventing leakage of urine, etc. The absorbent core is composed of a mixture of pulp fibers and superabsorbent polymer wrapped in nonwoven fabric or tissue. In sanitary materials, when the sanitary materials are worn, the absorbent core, surface sheet, and back sheet are arranged in the order of surface sheet, absorbent core, and back sheet from the side closest to the wearer. 【0003】 In recent years, with the widespread use of sanitary materials such as disposable diapers and sanitary napkins, there has been a growing demand for improved comfort through increased flexibility in these products. However, conventional absorbents using pulp fibers have the problem of being bulky and not flexible enough. Therefore, as an absorbent that does not use pulp fibers, an absorbent is known that is constructed by laminating a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric in this order (see, for example, Patent Documents 1 and 2). 【0004】 International Publication No. 2019 / 198821, International Publication No. 2013 / 099635 【0005】 However, the inventors have found that conventional absorbents have the following problems. The absorbent described in Patent Document 1 does not use bulky pulp fibers in the absorbent, but is an absorbent made by laminating a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric in this order. However, since the second nonwoven fabric is an air-through nonwoven fabric, it is very bulky compared to other nonwoven fabrics, and as a result, absorbents that include an air-through nonwoven fabric have the problem of insufficient overall flexibility. 【0006】Furthermore, the absorbent material described in Patent Document 2 does not use bulky pulp fibers in the absorbent material, and is an absorbent material made by laminating a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric in this order. The second nonwoven fabric in Patent Document 2 is a nonwoven fabric that does not allow particulate matter such as superabsorbent polymers to pass through, in order to separate the first group of superabsorbent polymers from the second group of superabsorbent polymers. A nonwoven fabric that does not allow particulate matter such as superabsorbent polymers to pass through is a nonwoven fabric that does not have through holes. It can also be said to be a nonwoven fabric in which the area of ​​the through holes is small and the number of through holes is extremely small. 【0007】 In the absorbent material described in Patent Document 2, the second nonwoven fabric does not have through holes, and no consideration is given to providing multiple through holes of an appropriate size in the second nonwoven fabric. If the second nonwoven fabric does not have through holes, or even if it does, if there are only a very small number of through holes, when the water-absorbing polymer group swells, a sufficient anchoring effect is not achieved between it and the nonwoven fabric, and the swollen water-absorbing polymer group tends to separate from the nonwoven fabric. As a result, the overall strength of the absorbent material decreases. This leads to the problem that when external forces such as vibration or shaking are applied to the vertical and vertically inclined parts of the absorbent material, the water-absorbing polymer group tends to separate from the nonwoven fabric. If the strength of the absorbent material decreases when swollen, when the absorbent material is used in disposable diapers, the wearer may experience discomfort in the fractional parts of the water-absorbing polymer group, making it unsuitable for practical use. Therefore, in view of the above circumstances, the object of the present invention is to provide an absorbent material that is flexible and also has excellent absorbent material strength when swollen. 【0008】 To solve the aforementioned problems, the present invention provides an absorbent material as follows: (1) an absorbent material comprising, in this order, a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric, wherein the second nonwoven fabric has a plurality of through holes, and the area of ​​each through hole is 1.5 to 10.0 mm². ２ It is within the range of 6.45 cm on each side of both sides of the second nonwoven fabric. ２ The absorbent has 10 to 75 of the aforementioned through holes within a certain range. 【0009】 (2) The absorbent material of (1), wherein a portion of the second nonwoven fabric is in contact with a portion of the first nonwoven fabric and a portion of the third nonwoven fabric. 【0010】 (3) The absorbent material of (1) or (2) is such that the 1-B surface of the first nonwoven fabric, which is the second nonwoven fabric side of the first nonwoven fabric side of the second nonwoven fabric, the 2-A surface of the second nonwoven fabric, which is the third nonwoven fabric side of the second nonwoven fabric, and the 3-A surface of the third nonwoven fabric, satisfy at least one of the following conditions I and II. <Condition I> The 2-A surface has a plurality of protrusions of different heights, and at least some of the protrusions are in close contact with the 1-B surface via a hot melt adhesive. <Condition II> The 2-B surface has a plurality of protrusions of different heights, and at least some of the protrusions are in close contact with the 3-A surface via a hot melt adhesive. 【0011】 (4) The 2-A surface of the second nonwoven fabric, which is the first nonwoven fabric side, and the 2-B surface of the second nonwoven fabric, which is the third nonwoven fabric side, are absorbents of any of (1) to (3) that satisfy at least one of the following conditions III and IV. <Condition III> There is no hot melt adhesive between the first superabsorbent polymer group and the 2-A surface, or the basis weight is 0.001 to 1 g / m ２ The presence of hot melt adhesive <Condition IV> There is no hot melt adhesive between the second group of superabsorbent polymers and the 2-B surface, or the basis weight is 0.001 to 1 g / m² ２ There is a hot melt adhesive available. 【0012】 (5) The second nonwoven fabric is an absorbent according to any of (1) to (4), wherein the content of the short fibers A is 15 to 70% by mass of the entire second nonwoven fabric, and the content of the short fibers A is 15 to 70% by mass of the entire second nonwoven fabric. 【0013】 (6) The basis weight of the first group of superabsorbent polymers is 300 g / m². ２ The following applies, and the basis weight of the second group of superabsorbent polymers is 300 g / m². ２The following is true, and the ratio of the basis weight of the first water-absorbent polymer group to the basis weight of the second water-absorbent polymer group (basis weight of the first water-absorbent polymer group / basis weight of the second water-absorbent polymer group) is 0.43 or more and 0.67 or less, and it is the absorber according to any one of (1) to (5). (7) The absorber in which the stiffness of the absorber is 90 mm or less, and it is the absorber according to any one of (1) to (6). 【0014】 (8) All of the first non-woven fabric, the second non-woven fabric, and the third non-woven fabric are spunlace non-woven fabrics, and the basis weight on the 1-B surface which is the surface of the first non-woven fabric on the side of the second non-woven fabric is 0.5 g / m ２ or more and 5.0 g / m ２ or less of a hot melt adhesive is present, and the basis weight on the 3-A surface which is the surface of the third non-woven fabric on the side of the second non-woven fabric is 0.5 g / m ２ or more and 5.0 g / m ２ or less of a hot melt adhesive is present, and it is the absorber according to any one of (1) to (7). 【0015】 (9) A sanitary material product including the absorber according to any one of (1) to (8). 【0016】 According to the present invention, it is possible to provide an absorber having flexibility and excellent absorber strength during swelling. 【0017】 It is a cross-sectional conceptual diagram showing an example of the configuration of the absorber of the present invention. It is a cross-sectional conceptual diagram showing an example of the configuration of the absorber of the present invention. It is a cross-sectional conceptual diagram of the absorber according to Comparative Example 2. 【0018】 Hereinafter, the actual form of the present invention will be described. Although the present invention will be described while appropriately referring to the drawings, the present invention is not limited by these drawings in any way. In addition, the description of the specific embodiment shown in the drawings can also be understood as the description of the present invention as a superior concept. 【0019】 The absorber of the present invention (reference numeral 10 in FIG. 1) is an absorber including a first non-woven fabric 1, a first water-absorbent polymer group 21, a second non-woven fabric 2, a second water-absorbent polymer group 22, and a third non-woven fabric 3 in this order. Further, the second non-woven fabric 2 includes a plurality of through-holes 4, and the area of the opening of each through-hole of the plurality of through-holes 4 is 1.5 to 10.0 mm２ It is included in the range. Also, on both sides of the second nonwoven fabric 2, sides 2-A and 2-B, there is 6.45 cm ２ It has 10 to 75 through-holes within that range. The absorbent of the present invention, possessing all of these features, is flexible and has excellent absorbent strength when swollen. The shape of the absorbent is typically rectangular, but Figure 1 is a conceptual diagram that shows an enlarged cross-section perpendicular to the long side of the rectangle to conceptually illustrate the structure of the absorbent. 【0020】 Here, swelling is the phenomenon in which the volume of an absorbent polymer increases as it absorbs liquids such as urine. In an absorbent body in which a group of absorbent polymers is held by a nonwoven fabric, the nonwoven fabric follows the swelling of the absorbent polymers, and as a result, the absorbent body itself also swells, which in this invention is referred to as the absorbent body in its swollen state. Furthermore, the absorbent body strength in its swollen state indicates whether the absorbent polymer group, which has swollen due to water absorption, can withstand vibration without separation occurring in the planar direction of the nonwoven fabric relative to the absorbent body. In this specification, "absorbent body strength in its swollen state" includes both the state in the vertical direction and the state in which the absorbent body is inclined with respect to the vertical direction. By making the absorbent body strength in its swollen state excellent, separation of the absorbent polymer group becomes less likely, and for example, when the absorbent body is used in disposable diapers, it is possible to suppress the discomfort that the wearer may experience due to the separation of the absorbent polymer group. 【0021】The mechanism by which the absorbent material exhibits superior strength when swollen is presumed to be as follows. The absorbent material of the present invention is placed inside a sanitary material product so that the first nonwoven fabric side faces the wearer of the sanitary material product. Liquids such as urine enter the absorbent material from the 1-A side of the first nonwoven fabric side and proceed through the interior of the absorbent material in the order of the first nonwoven fabric, the first superabsorbent polymer group, the second nonwoven fabric, the second superabsorbent polymer group, and the third nonwoven fabric. In the absorbent material of the present invention, the second nonwoven fabric is provided with a plurality of through holes 4, and by defining the size of the opening area of ​​the through holes and the number of through holes, the swollen first superabsorbent polymer group and / or a part of the second superabsorbent polymer group enter the through holes of the second nonwoven fabric (Figure 1), and the superabsorbent polymer group exhibits an anchoring effect (reference numeral 6) with respect to the second nonwoven fabric. As a result, the swollen first group of water-absorbing polymers and / or the second group of water-absorbing polymers are firmly fixed to the second nonwoven fabric, and the load is evenly distributed between the second nonwoven fabric and the swollen first group of water-absorbing polymers and / or the second group of water-absorbing polymers. In this case, it is important that the number of through holes 4 in the second nonwoven fabric 2 is such that water-absorbing polymer particles can easily enter and sufficient absorbent strength can be obtained when wet. As a result, localized stress concentration is reduced in response to vibration and shaking, and as a result, separation of the swollen first group of water-absorbing polymers and / or the second group of water-absorbing polymers can be suppressed. 【0022】 Furthermore, the second nonwoven fabric has a larger surface area, increasing the contact area between the second nonwoven fabric and the swollen first and / or second water-absorbing polymer groups. This increases the frictional force between the second nonwoven fabric and the swollen first and / or second water-absorbing polymer groups, allowing the swollen first and / or second water-absorbing polymer groups to be fixed in place. As a result, the overall strength of the absorber against vibration and shaking becomes superior. Note that the second nonwoven fabric in the conventional technology shown in Figure 3 is a fractionated water-absorbing polymer with no through holes, and there was no anchoring effect between the water-absorbing polymer groups and the nonwoven fabric. 【0023】Furthermore, from the viewpoint of achieving superior absorbent strength during swelling, the absorbent of the present invention preferably has the following configuration. In the absorbent of the present invention, it is preferable that the 1-B surface (see Figure 2), which is the surface of the first nonwoven fabric facing the second nonwoven fabric, the 2-A surface, which is the surface of the second nonwoven fabric facing the first nonwoven fabric, the 2-B surface, which is the surface of the second nonwoven fabric facing the third nonwoven fabric, and the 3-A surface, which is the surface of the third nonwoven fabric facing the second nonwoven fabric, satisfy at least one of the following conditions I and II. Either condition I or condition II may be satisfied, or both conditions I and II may be satisfied. Condition I is that the 2-A surface of the second nonwoven fabric has a plurality of protrusions of different heights, and at least some of the protrusions are in close contact (reference numeral 5) with the 1-B surface of the opposing first nonwoven fabric via a hot melt adhesive. Condition II is that the 2-B surface of the second nonwoven fabric has multiple protrusions of different heights, and at least some of these protrusions are in close contact with the 3-A surface of the opposing third nonwoven fabric via a hot melt adhesive. 【0024】 This configuration improves the interlayer bonding strength as the protrusions adhere closely to the adjacent nonwoven fabric via the adhesive, increasing the retention of the first and / or second water-absorbing polymer groups and fixing them to the absorber. As a result, separation of the swollen first and / or second water-absorbing polymer groups can be suppressed. Furthermore, the different heights of the protrusions create a three-dimensional uneven structure on the bonding surface, resulting in a larger surface area for the second nonwoven fabric and increasing the contact area between the second nonwoven fabric and the swollen first and / or second water-absorbing polymer groups. In addition, the three-dimensional uneven structure created by the different heights of the protrusions provides an anchoring effect to the first and / or second water-absorbing polymer groups, resulting in even load distribution between layers and reduced localized stress concentration. As a result, the overall strength of the absorber against vibration and shaking becomes evenly improved. 【0025】<Second Nonwoven Fabric> Next, the second nonwoven fabric provided in the absorbent of the present invention will be described in detail. The second nonwoven fabric has a plurality of through holes 4, and the area of ​​each through hole 4 is 1.5 to 10.0 mm ２ It is included in the range. Also, 6.45 cm on each side of both sides of the second nonwoven fabric 2, side 2-A and side 2-B. ２ The number of through holes 4 within this range ranges from 10 to 75. The area of ​​each through hole 4 is 1.5 to 10.0 mm². ２ The range is 6.45 cm on each side of both sides of the second nonwoven fabric. ２ By setting the number of through-holes within this range to 10 to 75, the strength of the absorbent material when swollen can be improved, the absorption rate of the liquid in the absorbent material can be increased, and the liquid flowability on the 2-A side of the first nonwoven fabric of the absorbent material can be improved. From the viewpoint of achieving the above effects even better, the area of ​​the opening of each through-hole in the multiple through-holes is 3.0 mm². ２ Preferably, it should be 8.0 mm or more. ２ The following is preferable. Also, 6.45 cm on each side of both sides of the second nonwoven fabric. ２ The number of through holes within the range is preferably 20 or more, and preferably 50 or less. 【0026】 Furthermore, the second nonwoven fabric 2 contains short fibers A having a single fiber strength of 0.15 N or more, and the content of short fibers A is preferably 15 to 70% by mass of the total mass of the second nonwoven fabric. Here, short fibers refer to fibers with a fiber length in the range of 10 to 100 mm. From the viewpoint of passability through the carding machine in the manufacturing process, it is more preferable that the fiber length of short fibers A is 20 to 80 mm. As described in the examples later, the single fiber strength of the short fibers is the maximum load of the elongation-load curve obtained when a tensile test is performed on a single short fiber. This is because, during the manufacturing of the second nonwoven fabric, even after going through processes that compress the short fibers in the planar direction, such as water jets and calenders, the repulsion due to the rigidity of the short fibers makes it easier to orient the fiber axis of the entire second nonwoven fabric in the thickness direction, resulting in a bulky nonwoven fabric and rough surfaces on both sides of the second nonwoven fabric. 【0027】 As a result, the frictional force between the second nonwoven fabric and the swollen first superabsorbent polymer group and / or the second superabsorbent polymer group increases, and the swollen superabsorbent polymer group can be fixed in place. As a result, the strength of the absorbent material when swollen can be improved. For the reason that this effect is more pronounced, it is more preferable that the second nonwoven fabric contains 30% by mass or more of short fibers A relative to the entire second nonwoven fabric. It is even more preferable that the second nonwoven fabric contains 40% by mass or more of short fibers A relative to the entire second nonwoven fabric. On the other hand, for the reason that it is possible to suppress a decrease in the diffusion of liquids such as urine into the second nonwoven fabric, suppress a decrease in the flexibility of the absorbent material, suppress an increase in the thickness of the absorbent material, and suppress a decrease in the flexibility of the absorbent material that affects the wearing comfort in sanitary material products, it is more preferable that the second nonwoven fabric contains 60% by mass or less of short fibers A relative to the entire second nonwoven fabric. 【0028】 Furthermore, examples of materials for the short fiber A include polyolefin short fibers such as polyethylene and polypropylene, polyester short fibers such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate, polyamide short fibers, and acrylic fibers such as acrylonitrile. Among these short fibers, polyester short fibers and polyamide short fibers are preferred due to their superior strength, handling properties, and productivity. Polyethylene terephthalate short fibers and nylon 6 or nylon 66 short fibers are even more preferred. 【0029】 Furthermore, it is preferable that the short fibers A are hollow fibers. By making them hollow fibers, the bulk of the short fibers A themselves increases, making it easier to orient the fiber axes of the entire second nonwoven fabric in the thickness direction. As a result, the rigid short fibers A protruding from each surface of both sides of the second nonwoven fabric act as anchors, increasing the frictional force between the second nonwoven fabric and the swollen first water-absorbing polymer group and / or the second water-absorbing polymer group, thereby fixing the swollen water-absorbing polymer group. Consequently, the strength of the absorbent material when swollen is improved. 【0030】<Methods for Manufacturing the First to Third Nonwoven Fabrics> Next, a specific method for manufacturing the first to third nonwoven fabrics used in the absorbent body of the present invention will be described. However, the methods for manufacturing the first to third nonwoven fabrics used in the absorbent body of the present invention are not limited to these. Furthermore, the methods for manufacturing the first to third nonwoven fabrics may be different for each of them. Short fibers used to obtain the first to third nonwoven fabrics of the present invention are fed into a carding machine, blended and opened, and then a uniform web is formed using a weaver. If the first to third nonwoven fabrics of the present invention are spunlace nonwoven fabrics, the web is then fed into a water jet type nonwoven fabrication apparatus and entangled with a high-pressure water stream to form a nonwoven fabric. After that, it is preferable to dry the nonwoven fabric in a hot air oven to obtain a spunlace nonwoven fabric. 【0031】 Furthermore, in the case of a rectangular absorbent material, the web is preferably a parallel web in which the fibers are oriented in the longitudinal direction, or a crisscross web containing a parallel web in which the fibers are oriented in the longitudinal direction, because improving the diffusion of liquids such as urine in the longitudinal direction improves the utilization efficiency of the superabsorbent polymer. Nonwoven fabrics obtained from these webs have a high degree of fiber orientation in the longitudinal direction. A crisscross web is made by laminating a cross web in which parallel webs are oriented in the short side direction using a cross layer or the like, and a parallel web. 【0032】 Methods for creating through-holes in a second nonwoven fabric include the injection of high-pressure water using a water jet device or a laser. In this process, opening members such as mesh molds or perforated metal can be used to create openings in specific patterns or shapes. 【0033】<First and Second Superabsorbent Polymer Groups> The absorbent material of the present invention includes a first superabsorbent polymer group and a second superabsorbent polymer group (hereinafter sometimes simply referred to as the "superabsorbent polymer group"). The superabsorbent polymer group is composed of superabsorbent polymers. Examples of superabsorbent polymers used in the present invention include starch, cross-linked carboxymethylated cellulose, polymers or copolymers thereof of acrylic acid or alkali metal acrylate salts, polyacrylates such as sodium polyacrylate, and polyacrylate graft polymers. Among these, sodium polyacrylate is preferred from the viewpoint of productivity. 【0034】 Furthermore, the superabsorbent polymer is preferably in particulate form from the viewpoint of ease of handling in the manufacturing process, etc. When the superabsorbent polymer is in particulate form, its particle size is preferably 50 to 850 μm. More specifically, the particle size of the superabsorbent polymer is measured by the method described in the section on measurement methods in the examples. Here, by setting the particle size of the superabsorbent polymer to 50 μm or more, it is possible to suppress the superabsorbent polymer from passing through the first nonwoven fabric and the third nonwoven fabric and leaking out to the outside of the absorbent material. On the other hand, by setting the particle size of the superabsorbent polymer to 850 μm or less, it is possible to suppress a decrease in the water absorption capacity of the superabsorbent polymer. 【0035】 The basis weight of the first and second groups of superabsorbent polymers is 50 to 400 g / m². ２ It is preferable that the basis weight of the first and second superabsorbent polymer groups be 75 g / m², in order to improve the absorption capacity of urine and other substances in the absorbent material. ２ The above is more preferable. On the other hand, in order to prevent reduced air permeability when used in sanitary material products, and to prevent the absorbent polymer that has absorbed urine, etc., from leaking out of the absorbent material due to its weight, the basis weight of the first and second groups of absorbent polymers should be 300 g / m². ２ The following is more preferable: 【0036】Furthermore, the ratio of the basis weight of the first superabsorbent polymer group to the basis weight of the second superabsorbent polymer group (basis weight of the first superabsorbent polymer group / basis weight of the second superabsorbent polymer group) is preferably 0.25 or more and 0.82 or less. More preferably, the lower limit of the ratio of the basis weight of the first superabsorbent polymer group to the basis weight of the second superabsorbent polymer group is 0.43, for the reason that this suppresses the separation of the superabsorbent polymer group caused by the imbalance in the mass distribution of the absorbent material during swelling, and consequently suppresses the decrease in the strength of the absorbent material during swelling. On the other hand, more preferably, the upper limit of the ratio of the basis weight of the first superabsorbent polymer group to the basis weight of the second superabsorbent polymer group is 0.67, for the reason that this suppresses the return of urine etc. absorbed by the second superabsorbent polymer group to the first superabsorbent polymer group and the second nonwoven fabric, thereby suppressing the gel block phenomenon and consequently improving the overall absorption characteristics of the absorbent material. 【0037】 When the basis weight of the second superabsorbent polymer group is higher than that of the first superabsorbent polymer group, it is preferable that the surface roughness of the surface of the second nonwoven fabric on the side with the second superabsorbent polymer group is greater than the surface roughness of the surface of the second nonwoven fabric on the side with the first superabsorbent polymer group. By doing so, the contact area between the second nonwoven fabric and the swollen second superabsorbent polymer group becomes larger than the contact area between the second nonwoven fabric and the swollen first superabsorbent polymer group, and the surface of the second nonwoven fabric on the side with the second superabsorbent polymer group has higher fixation of the swollen superabsorbent polymer group than the surface of the second nonwoven fabric on the side with the first superabsorbent polymer group. As a result, when the basis weight of the second superabsorbent polymer group is higher than that of the first superabsorbent polymer group, the separation of the superabsorbent polymer group caused by the imbalance in the mass distribution of the absorbent during swelling can be suppressed, and consequently, the decrease in absorbent strength during swelling can be suppressed. 【0038】<Absorbent Material> The absorbent material of the present invention comprises a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric, in this order. With this configuration, when the absorbent material of the present invention is used in sanitary material products such as diapers, and the first nonwoven fabric is positioned on the wearer's side within the sanitary material product, urine etc. released from the wearer quickly penetrates into the absorbent material, is quickly absorbed by the superabsorbent polymers, and retains moisture. Therefore, the wearer is less likely to experience discomfort when wearing the product, and a sanitary material product with less leakage of urine etc. can be made. 【0039】 In this case, it is preferable that a portion of the second nonwoven fabric is in contact with a portion of the first nonwoven fabric and a portion of the third nonwoven fabric in the absorbent material of the present invention. When a portion of the second nonwoven fabric is in contact with a portion of the first nonwoven fabric and a portion of the third nonwoven fabric, frictional force is generated between the second nonwoven fabric and the first nonwoven fabric and / or between the second nonwoven fabric and the third nonwoven fabric, improving the fixation of the swollen first superabsorbent polymer group and / or the second superabsorbent polymer group. As a result, the strength of the absorbent material is improved against vibration and shaking. From the above viewpoint, it is more preferable that at least a portion of the contact points between the second nonwoven fabric and the first nonwoven fabric and / or at least a portion of the contact points between the second nonwoven fabric and the third nonwoven fabric are fixed. Examples of fixing materials include hot melt adhesives and heat-sealable resin powders. Furthermore, from the viewpoint of improving the flexibility of the absorbent material of the present invention, it is preferable that the hot melt adhesive is included only in the first nonwoven fabric and / or the third nonwoven fabric, and that the hot melt adhesive is not applied to the 2-A and 2-B sides of the second nonwoven fabric. 【0040】 In other words, it is preferable that the 2-A side and 2-B side of the second nonwoven fabric 2 satisfy at least one of conditions III and IV. Condition III is that there is no hot melt adhesive between the first superabsorbent polymer group and the 2-A side of the second nonwoven fabric, or the basis weight is 0.001 to 1 g / m². ２ There are hot melt adhesives available. Here, the basis weight of the hot melt adhesive is 0.001 to 1 g / m². ２This means that the basis weight of the hot melt adhesive is extremely small and does not impede the flexibility of the absorbent material. In other words, even if hot melt adhesive is present, a value of 0.001 g / m is small enough to allow flexibility. ２ From 1 g / m ２ Therefore, given this situation, the basis weight of the hot melt adhesive when it is present is 0.001 g / m². ２ From 0.5 g / m ２ It is more preferable to be less than 0.001 g / m³. ２ From 0.3 g / m ２ It is even more preferable that the concentration be 0.001 g / m ２ From 0.1 g / m ２ It is particularly preferable that the following conditions are met. Condition IV is that there is no hot melt adhesive between the second superabsorbent polymer group and the 2-B side of the second nonwoven fabric, or the basis weight is 0.001 to 1 g / m². ２ There are hot melt adhesives available. Here, the basis weight of the hot melt adhesive is 0.001 to 1 g / m². ２ This means that the basis weight of the hot melt adhesive is extremely small and does not impede the flexibility of the absorbent material. In other words, even if hot melt adhesive is present, the value is small enough to allow flexibility to be maintained, ranging from 0.001 g to 1 g / m². ２ Therefore, given this situation, the basis weight of the hot melt adhesive when it is present is 0.001 g / m². ２ From 0.5 g / m ２ It is more preferable to be less than 0.001 g / m³. ２ From 0.3 g / m ２ It is even more preferable that the concentration be 0.001 g / m ２ From 0.1 g / m ２ This configuration is particularly preferable. With this configuration, the amount of adhesive between the superabsorbent polymers and the nonwoven fabric is extremely small or nonexistent, resulting in flexible interlayer bonding throughout the absorbent material and increased interlayer mobility. As a result, the absorbent material can exhibit excellent flexibility. 【0041】Furthermore, from the viewpoint of further improving the balance between the flexibility and strength of the absorbent material, the absorbent material of the present invention preferably has the following configuration. In the absorbent material of the present invention, the first nonwoven fabric, the second nonwoven fabric, and the third nonwoven fabric are all spunlace nonwoven fabrics, and between the 1-B side (Figure 1) of the first nonwoven fabric and the first superabsorbent polymer group, the basis weight is 3.5 g / m². ２ The following hot melt adhesives exist, and between the 3-A side of the third nonwoven fabric and the second group of superabsorbent polymers, the basis weight is 3.5 g / m². ２ The following hot-melt adhesives are preferable. With this configuration, while utilizing the inherent flexibility of the spunlace nonwoven fabric, the basis weight of the hot-melt adhesive can be reduced, allowing each layer of the absorbent to be appropriately bonded while suppressing a decrease in flexibility. This achieves a balance between the overall flexibility of the absorbent and strength, such as suppression of shedding of the superabsorbent polymers and suppression of delamination between layers. As a result, the balance between the flexibility and strength of the absorbent can be further improved. 【0042】 The absorbent material of the present invention is preferably in the form of a substantially rectangular sheet, similar to absorbent materials used in known sanitary materials such as diapers. Furthermore, the absorbent material of the present invention is preferably 90 mm or less in rigidity. When the absorbent material of the present invention is used in sanitary materials such as diapers, the sanitary materials using the absorbent material of the present invention become flexible, stiffness is suppressed, and the wearing comfort is improved. In addition, the sanitary materials can be folded easily when packaging, and the packaging size can be reduced. For these reasons, the rigidity of the absorbent material is more preferably 80 mm or less, and even more preferably 70 mm or less. The rigidity thickness referred to here is measured according to JIS L1096 (2022) 8.21.1 Method A (45° cantilever method). The lower the rigidity value, the better the flexibility. Furthermore, the absorbent material of the present invention can be made even more flexible and less rigid by having a configuration in which hot melt adhesive is not present on a specific surface of the second nonwoven fabric, or is present in a very small amount, or by having a configuration in which the entire nonwoven fabric layer is made of spunlace nonwoven fabric. 【0043】Furthermore, the absorbent material of the present invention is preferably 4.0 mm or less in thickness. A thickness of 4.0 mm or less allows the absorbent material to be used in sanitary products such as diapers, resulting in a more flexible product with reduced stiffness and improved comfort. For the sake of improving the comfort of the sanitary product, a thinner absorbent material is preferable, more preferably 3.0 mm or less in thickness, and even more preferably 2.5 mm or less. On the other hand, for the sake of improving the absorbent properties of the absorbent material, a thickness of 1 mm or more is preferable. Note that the thickness of the absorbent material refers to the measurement based on JIS L1913 (2022) 6.1.1 Method A. 【0044】 Regarding the fixation of the superabsorbent polymer groups, it is preferable that the first superabsorbent polymer group is fixed to the first nonwoven fabric, and the second superabsorbent polymer group is fixed to the third nonwoven fabric. Examples of materials for fixing the superabsorbent polymer groups to the nonwoven fabric include hot melt adhesives and heat-sealable resin powders. As hot melt adhesives, styrene-based hot melt adhesives or olefin-based hot melt adhesives suitable for sanitary material product applications can be used as suitable materials. Furthermore, as heat-sealable resin powders, polyethylene powder or ethylene-vinyl acetate copolymer powder can be suitably used from the viewpoint that heat sealing can be performed at relatively low temperatures. As a material for fixing the superabsorbent polymer groups to the nonwoven fabric, hot melt adhesives are more preferable because they can be fixed with a low basis weight. 【0045】 The basis weight of the hot melt adhesive present on the first 1-B surface, which is the side of the first nonwoven fabric facing the second nonwoven fabric, and on the third 3-A surface, which is the side of the third nonwoven fabric facing the second nonwoven fabric, is 0.5 to 5.0 g / m² in both cases. ２It is preferable that the above-mentioned basis weight of the hot melt adhesive allows for the fixation of the superabsorbent polymer on the nonwoven fabric, improves the adhesion of some contact points between the first and third nonwoven fabrics and the second nonwoven fabric, and increases the strength of the absorbent material when swollen. For the same reasons as above, the basis weight of the hot melt adhesive between the superabsorbent polymer group and the nonwoven fabric is 1.0 g / m². ２ In addition to the above, 1.5 g / m ２ The above is more preferable. On the other hand, for the reason that it can suppress the inhibition of the expansion of the superabsorbent polymer by the hot melt adhesive, the basis weight of the hot melt adhesive between the superabsorbent polymer group and the nonwoven fabric is 3.5 g / m². ２ The following is more preferable: 【0046】 The absorbent strength of the absorbent material of the present invention when swollen is preferably 100 times or more. In the present invention, the absorbent strength when swollen is defined as the number of times the absorbent material, swollen with physiological saline, is suspended vertically and shaken up and down until separation occurs in the planar direction relative to the absorbent material within the swollen superabsorbent polymer group. More details are described in the section on measurement methods in the examples. By using the absorbent material of the present invention in sanitary material products, the absorbent strength when swollen is excellent, and the separation of the swollen superabsorbent polymer group within the absorbent material can be suppressed when physical force is applied to the absorbent material, such as when walking or sitting while wearing it. From the above viewpoint, the absorbent strength when swollen is more preferably 200 times or more, and even more preferably 300 times or more. As a means of obtaining such an absorbent material, for example, one can use the materials described in Example 1 and employ the manufacturing method described in Example 1. The absorbent strength during swelling can be set to the above range by appropriately adjusting one or more of the following: the opening area of ​​each of the multiple through holes in the second nonwoven fabric, the number of through holes on each surface of both sides of the second nonwoven fabric, the content of short fibers A in the second nonwoven fabric, the ratio of basis weights of the first superabsorbent polymer group to the second superabsorbent polymer group, and the basis weight of the hot melt adhesive between the superabsorbent polymer group and the nonwoven fabric. 【0047】The absorbent material of the present invention preferably has an absorption capacity of 150 g or more. In the present invention, the absorption capacity refers to the weight of physiological saline absorbed by the absorbent material when physiological saline is dropped onto the sample at a 45° inclination until the physiological saline leaks out from the lower side of the sample. A more detailed measurement method is described in the examples. By using the absorbent material of the present invention in sanitary material products, excellent leakage prevention is achieved, and leakage can be suppressed when the sanitary material product is in an inclined state, such as when lying down while wearing it. From the above viewpoint, the absorption capacity of the absorbent material is more preferably 175 g or more, and even more preferably 200 g or more. As a means of obtaining such an absorbent material, for example, one can use the materials described in Example 1 and employ the manufacturing method described in Example 1. The absorption capacity of the absorbent material can be brought within the above range by optimizing the type of nonwoven fabric, the rayon ratio contained in the nonwoven fabric, the size and number of through holes in the second nonwoven fabric, the type of superabsorbent polymer group, the basis weight of the superabsorbent polymer group, the ratio of the basis weight of the first superabsorbent polymer group to the basis weight of the second superabsorbent polymer group, the basis weight of the hot melt adhesive, etc. 【0048】<Method for Manufacturing the Absorbent Material> The method for manufacturing the absorbent material of the present invention will be described in detail below, but the method for manufacturing the absorbent material of the present invention is not limited to the following. An absorbent material is obtained by fixing a group of superabsorbent polymers between a first nonwoven fabric and a second nonwoven fabric, and between the second nonwoven fabric and a third nonwoven fabric. As a method for fixing the group of superabsorbent polymers, (1) a hot melt adhesive is uniformly sprayed or spirally onto one side of the third nonwoven fabric. Next, the second superabsorbent polymer is uniformly sprayed on top of it. Next, one side of the second nonwoven fabric is pressed onto it. Next, the first superabsorbent polymer is uniformly sprayed onto the other side of the second nonwoven fabric (the side on which the second superabsorbent polymer has not been sprayed). Alternatively, a hot melt adhesive may be sprayed or spirally onto one side of the first nonwoven fabric. Furthermore, the method involves pressing together the other side of the second nonwoven fabric (the side on which the first superabsorbent polymer is applied) and one side of the first nonwoven fabric (the side on which the hot melt adhesive is applied), or (2) a method in which a pre-mixed, uniform mixture of heat-fusible resin powder and the first superabsorbent polymer is applied to one side of the first nonwoven fabric, the second nonwoven fabric is placed over the first superabsorbent polymer group and heated to a temperature above the melting point of the heat-fusible powder to heat-press it, and then the pre-mixed, uniform mixture of heat-fusible resin powder and the second superabsorbent polymer is applied to the other side of the second nonwoven fabric, the third nonwoven fabric is placed over the second superabsorbent polymer group and heated to a temperature above the melting point of the heat-fusible powder to heat-press it. 【0049】<Sanitary Material Products and Manufacturing Methods> The absorbent material of the present invention is flexible and has excellent absorbent strength when swollen, making it suitable for use in various sanitary material products such as tape-type disposable diapers, pant-type disposable diapers, sanitary napkins, and incontinence pads. A method for manufacturing sanitary material products such as disposable diapers and napkins using the absorbent material of the present invention will be described. In order to prevent the superabsorbent polymer from falling off from both ends in the width direction of the absorbent material, the absorbent material of the present invention may be wrapped entirely or partially with a covering material such as a core wrap sheet so that both ends in the width direction are covered, leaving the top open. The absorbent material or the absorbent material wrapped in the covering material is sandwiched and fixed between a surface sheet and a back sheet. The surface sheet side is the skin-facing side for use, and the back sheet is the side opposite to the skin-facing side for use. Here, it is preferable to sandwich the absorbent material between the surface sheet and the back sheet so that the first nonwoven fabric or covering material (first nonwoven fabric side) of the absorbent material is in contact with the surface sheet. The first nonwoven fabric has the characteristic of allowing aqueous liquids to easily permeate from one side to the other. Therefore, when the surface sheet comes into contact with the first nonwoven fabric, the aqueous liquid that has penetrated into the surface sheet quickly permeates the first nonwoven fabric, is absorbed by the superabsorbent polymer, and is easily retained. Thus, the absorption characteristics of the absorbent material can be improved. 【0050】 Methods for fixing the parts in direct contact between the surface sheet and the absorbent, the back sheet and the absorbent, and the surface sheet and the back sheet include using a hot-melt adhesive or a heat-sealable resin powder. Furthermore, when the absorbent of the present invention is made into a sanitary material product, it is preferable to use a nonwoven fabric as the surface sheet from the viewpoint of having better liquid permeability and tactile properties. For example, wet nonwoven fabrics, resin-bonded dry nonwoven fabrics, thermal-bonded dry nonwoven fabrics, spunbonded dry nonwoven fabrics, needle-punched dry nonwoven fabrics, water-jet-punched dry nonwoven paper fabrics or flash-spun dry nonwoven fabrics can be used, as well as nonwoven fabrics manufactured by papermaking methods that can produce uniform basis weight and thickness. Among these, it is preferable to use a thermal-bonded dry nonwoven fabric as the surface sheet from the viewpoint of having excellent tactile properties, as it is located in a place that comes into contact with human skin. 【0051】Furthermore, when the absorbent material of the present invention is made into a sanitary material product, the backing sheet used is preferably a laminated sheet of a breathable waterproof film and a nonwoven fabric, from the viewpoint of allowing water vapor accumulated inside the sanitary material product to escape to the outside to provide comfort to the wearer, and from the viewpoint of providing excellent waterproofness and tactile feel. Examples of the above-mentioned breathable waterproof film include porous polyethylene film, breathable urethane film, and breathable polyester elastomer film. As for the above-mentioned nonwoven fabric, the same nonwoven fabric as the surface sheet can be used, but from the viewpoint of cost and strength, a spunbond dry nonwoven fabric is preferred. 【0052】 The present invention will be described in detail below based on examples, but the present invention is not limited to these. Furthermore, the performance in the examples was measured by the following method. [Measurement method] (1) A second nonwoven fabric taken from the pore area absorber of the through hole was used as a test piece, and 6.45 cm was measured at five locations on one side and the other side of the test piece. ２ Observation areas within this range were randomly selected, and photographs were taken at a magnification of 6x at a total of 10 observation areas, with a measurement of 6.45 cm. ２ The images were taken to capture the entire area. Next, each of the 10 obtained images was processed using image processing software (software name: WinROOF, manufactured by Mitani Corporation), and the area of ​​each through-hole in each image was measured. The average of the measured through-hole areas was used to determine the opening area (mm²) of each through-hole. ２ ) 【0053】 (2) Number of through holes In each of the 10 photographs obtained in (1) above, 6.45 cm ２ The area of ​​each through-hole in the range is 1.5 to 10.0 mm². ２ The number of through-holes within the specified range was counted, and the average number of through-holes in the 10 photographs was taken as the total number of through-holes. 【0054】(3) Fiber content of the nonwoven fabric Based on JIS L 1030-1 (2012) "Test method for blend ratio of textile products - Part 1: Fiber identification" and JIS L 1030-2 (2012) "Test method for blend ratio of textile products - Part 2: Fiber blend ratio", the correct blend ratio (mass ratio of each fiber under standard conditions) was measured and this was taken as the fiber content (mass %) of the nonwoven fabric. 【0055】 (4) Basis weight of nonwoven fabric Based on JIS L 1913 (2010) 6.2, the unit area (1 m²) of the sample ２ Mass per unit (g / m³) ２ ) was sought. 【0056】 (5) Single fiber strength of short fibers The single fiber strength was measured in accordance with JIS L1015 (2010) 8.7.1. Specifically, a sample was prepared by loosely stretching a single fiber and attaching both ends of the fiber to paper with adhesive, with the paper attached portion serving as the gripping part. At this time, a region of 20 mm consisting only of the fiber between the gripping parts was ensured. The gripping part of this sample was attached to the grips of a tensile testing machine (Orientec Co., Ltd. Tensilon universal testing machine model RTG-1210), and pulled at a gripping distance of 10 mm and a tensile speed of 10 mm / min. The maximum load in the obtained elongation (mm)-load (N) curve was taken as the single fiber strength (N). Measurements were performed on 10 samples for each short fiber, and the average value was taken as the single fiber strength of the short fiber. 【0057】 (6) Particle size of the superabsorbent polymers in the superabsorbent polymer group A total of 5.00 g of superabsorbent polymers was collected from the superabsorbent polymer group. The collected 5.00 g of superabsorbent polymers was classified using a tray and sieves with nominal mesh sizes of 75 μm, 106 μm, 212 μm, 300 μm, 425 μm, 500 μm, 600 μm, 710 μm, 850 μm, 1 mm (1000 μm), and 1.4 mm in accordance with JIS Z8801. An automatic shaker (AS ONE horizontal rotating sieve SKH-01) was used for classification, and the shaker was operated for 10 minutes at a memory setting of 3. The mass of the superabsorbent polymers on each sieve and tray was measured, and the particle size distribution of the superabsorbent polymers was obtained using the results. Here, the particle size corresponding to 50% by mass in the overall particle size distribution of the superabsorbent polymers was defined as the particle size of the polymers in the superabsorbent polymer group in this invention. 【0058】 (7) Ten absorbent samples (10 cm x 10 cm) were left standing for 24 hours or more under standard conditions for the basis weight of the superabsorbent polymer group. Superabsorbent polymers were then collected from the superabsorbent polymer group of each sample. Next, the mass (g) of each under standard conditions was measured, and 1 m ２ Mass per unit (g / m³) ２ ) is determined, and the average value of 10 points is calculated, and the basis weight (g / m²) of the superabsorbent polymer group in this invention is calculated. ２ ) 【0059】 (8) Rigidity of the absorber Based on JIS L1096 (2022) 8.21.1 Method A (45° cantilever method), the rigidity of one side and the other side of the absorber were measured with n=5 each, and the average value of 10 measurements was calculated and defined as rigidity (mm). 【0060】 (9) Absorber Thickness Based on JIS L1913 (2022) 6.1.1 Method A, the thickness of the sample was measured using a thickness measuring instrument (TECLOCK constant pressure thickness measuring instrument, model: PG11J). Measurements were taken for each sample piece (5 pieces), and the average value was calculated to determine the absorber thickness (mm). 【0061】 (10) Absorbent Strength When Swelled A sample was prepared by cutting an absorbent to a size of 12 cm in width and 22.5 cm in length and stapling the four ends of the absorbent. 50 ml of physiological saline (0.90 mass% sodium chloride aqueous solution colored with blue dye), which had been prepared in a beaker beforehand, was quickly poured into the center of the sample and left to stand for 3 minutes. Next, 50 ml of physiological saline was quickly poured into the position where the midpoint between the top end and the center in the length direction of the sample intersects with the midpoint in the width direction of the sample and left to stand for 3 minutes. Next, 50 ml of physiological saline was quickly poured into the position where the midpoint between the bottom end and the center in the length direction of the sample intersects with the midpoint in the width direction of the sample and left to stand for 3 minutes to prepare a swollen sample (absorbent). 【0062】Next, the sample was attached to a stainless steel ruler measuring 5 cm wide x 60 cm long using clips so that one end of the sample in the longitudinal direction overlapped with the 24 cm and 36 cm markings of the ruler. Then, holding both ends of the ruler with both hands, the ruler and sample were lowered into an open-top glass container measuring 30 cm wide, high, and deep, so that the sample was perpendicular and the ruler was parallel. The process was stopped when the ends of the ruler that were not holding the sample touched the container, and this point was designated as point A. Next, the ruler was raised vertically 7.5 cm upwards (point B). After that, it was allowed to fall from point B to point A by its own weight. This vertical movement between point A and point B was counted as one cycle, and the number of vertical movements until a separation of 5 cm or more in the planar direction relative to the absorbent polymer group, which had swollen due to absorbing physiological saline solution in the sample (absorbent material), was observed was defined as the absorbent strength at the time of swelling (measured with n=5, and the average value was adopted). Furthermore, the absorbent strength during swelling improved with each subsequent test. The temperature of the physiological saline solution and the measurement atmosphere used was 20±2°C. In addition, to facilitate the separation of the swollen superabsorbent polymer group inside the sample (absorbent), the test was conducted with a light projected from behind the sample. 【0063】(11) The presence or absence of protrusions of different heights on the second nonwoven fabric was determined by observation with a microscope. Specifically, UV-curing resin (UVJ-1, manufactured by Taiyo Ki Kogyo Co., Ltd.) was applied to the release surface of a silicone release film, and 20 mm square samples randomly taken from the absorber were placed on the UV-curing resin with the third nonwoven fabric side facing downwards, so that the UV-curing resin covered the entire sample. Furthermore, a similar silicone release film was placed on top, and the resin was cured by UV irradiation for 2 minutes using a UV irradiation device (UV-1, manufactured by Taiyo Ki Kogyo Co., Ltd.) to embed and fix the absorber sample. After that, it was left to stand for more than 1 hour, and the central part of the sample was cut out to obtain a resin-embedded sample. Next, this resin-embedded sample was cut with a microtome, and the obtained cross-section was observed at a magnification of 25x using a microscope (VHX-6000, manufactured by Keyence Corporation). If multiple protrusions of different heights are clearly visible within the same field of view of the observed cross-section, it was determined that the second nonwoven fabric has protrusions of different heights. 【0064】 (12) Absorption amount of the absorbent The backing sheet and the absorbent (sample) were fixed in that order on a stainless steel inclined stand with a 45° inclination angle. The sample was fixed so that its longitudinal direction coincided with the inclination direction, the third nonwoven fabric side was in contact with the backing sheet, and it was stretched out to eliminate wrinkles. A porous polyethylene film was used for the backing sheet. Next, physiological saline (0.90% by mass sodium chloride aqueous solution colored with blue dye), which had been prepared in advance in a beaker, was dropped from a microtube pump at a rate of 1.5 g / second, and the dropping of physiological saline was continued until leakage of physiological saline was observed from the lower end surface of the sample. 500 g of physiological saline was prepared in a beaker, and the physiological saline was dropped in the above inclined state, and the dropping was stopped when leakage of physiological saline was observed from the lower end surface of the sample. The weight Q (g) of the physiological saline that remained in the beaker without being dropped was measured, and the absorption amount of the absorbent was calculated using the following formula. The temperature of the physiological saline solution and the measurement atmosphere used was 20 ± 2°C. A higher absorption value indicates superior leakage prevention. Absorption capacity of absorbent material (g) = 500g - Q 【0065】(13) Overall Evaluation The overall evaluation of the absorbers obtained was carried out according to the following criteria. A and B were considered good. A: Absorber strength when swollen is 200 times or more, and rigidity is 90 mm or less. B: Absorber strength when swollen is 100 times or more and 199 times or less, and rigidity is 90 mm or less. C: Absorber strength when swollen is 99 times or less, and rigidity is greater than 90 mm, satisfying at least one of these conditions. 【0066】 [Example 1] An absorbent material comprising a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric in this order was used. The first nonwoven fabric was made by blending 70% by mass of rayon short fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) and 30% by mass of hollow short fibers made of polyethylene terephthalate (fiber diameter: 30 μm, fiber length: 51 mm, single fiber strength: 0.30 N) (hereinafter, the above hollow short fibers will be referred to as "short fibers A") using a card, opening the fibers, and then weaving them to a basis weight of 30 g / m². ２ This was used to create a parallel web. The resulting parallel web was entangled with a high-pressure water jet and dried at 150°C for 3 minutes, resulting in a basis weight of 30 g / m². ２ A first nonwoven fabric a, which is a spunlace nonwoven fabric, was obtained. 【0067】 The second nonwoven fabric is made by carding together 70% by mass of rayon short fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) and 30% by mass of short fibers A (fiber diameter: 30 μm, fiber length: 51 mm, single fiber strength: 0.30 N), then opening the fibers, and finally weaving them to a basis weight of 40 g / m². ２ This was used to create a parallel web. The resulting parallel web was entangled with a high-pressure water jet and dried at 150°C for 3 minutes, resulting in a basis weight of 40 g / m². ２ A spunlace nonwoven fabric was obtained. The obtained spunlace nonwoven fabric was opened into a perforated member (opening area 4.0 mm) ２ / piece, number of openings: 25 / 6.45 cm ２ By spraying a high-pressure water stream onto the spunlace nonwoven fabric, through-holes are formed, and by drying at 150°C for 3 minutes, the basis weight reaches 40 g / m². ２A second nonwoven fabric a was obtained, which is a spunlace nonwoven fabric having multiple through holes. Here, the side of the second nonwoven fabric to which the high-pressure water jet was injected was designated as surface 2-A, and the opposite side was designated as surface 2-B. The proportion of short fibers A contained in the second nonwoven fabric a was 30% by mass of the entire second nonwoven fabric a. Surfaces 2-A and 2-B of the second nonwoven fabric had protrusions of different heights. 【0068】 The third nonwoven fabric is made from rayon short fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N), which are opened with a card and then processed with a weaver to a basis weight of 30 g / m². ２ This was used to create a parallel web. The resulting parallel web was subjected to a high-pressure water stream to entangle it, and dried at 150°C for 3 minutes to obtain a basis weight of 30 g / m². ２ A third nonwoven fabric a, which is a spunlace nonwoven fabric, was obtained. 【0069】 The absorbent material has 2 g / m² of styrene-based hot melt adhesive applied to one side of the third nonwoven fabric, side 3-A. ２ The surface is sprayed on, and then a second superabsorbent polymer (SDP Global IM930) is applied on top at a basis weight of 150 g / m². ２ The material was then spread evenly. Next, the 2-B side of the second nonwoven fabric was placed on top and pressed down. Then, 2 g / m of styrene-based hot melt adhesive was applied to one side of the first nonwoven fabric. ２ The mixture is sprayed in this manner, and then the first superabsorbent polymer (SDP Global IM930) is applied on top at a basis weight of 100 g / m². ２ The material was uniformly scattered in this manner. Next, the 2-A side of the second nonwoven fabric (the side opposite to the side on which the second superabsorbent polymer was scattered) was placed over the first nonwoven fabric and pressed down so that it was in contact with the first superabsorbent polymer scattered on the first nonwoven fabric. Here, a portion of the second nonwoven fabric was in close contact with a portion of the first nonwoven fabric and a portion of the third nonwoven fabric via hot melt adhesive. The obtained material was cut into a rectangle with a long side of 20 cm and a short side of 10 cm to obtain a rectangular absorbent body. The composition and performance of this absorbent body are shown in Table 1. The rigidity of this absorbent body was 67 mm, and the absorbent body strength when swollen was 250 times, demonstrating both flexibility and excellent absorbent body strength when swollen. The composition and performance of the example and comparative example are shown in Tables 1 to 4 below. 【0070】 [Example 2] An opening member for providing through holes in the second nonwoven fabric has an opening area of ​​6.0 mm ２ / piece, number of openings: 20 / 6.45 cm ２ An absorber was obtained in the same manner as in Example 1, except that the perforated member was changed to the one shown. The rigidity of this absorber was 69 mm, and the absorber strength when swollen was 245 times, demonstrating both flexibility and excellent absorber strength when swollen. 【0071】 [Example 3] An opening member for providing a through hole in the second nonwoven fabric has an opening area of ​​3.0 mm ２ / piece, number of openings: 40 / 6.45 cm ２ An absorber was obtained in the same manner as in Example 1, except that the perforated member was changed to the one shown. The rigidity of this absorber was 65 mm, and the absorber strength when swollen was 260 times, demonstrating both flexibility and excellent absorber strength when swollen. 【0072】 [Example 4] An opening member for providing through holes in the second nonwoven fabric has an opening area of ​​1.5 mm ２ / piece, number of openings: 25 / 6.45 cm ２ An absorber was obtained in the same manner as in Example 1, except that the perforated member was changed to the one shown. The rigidity of this absorber was 70 mm, and the absorber strength when swollen was 110 times, demonstrating both flexibility and excellent absorber strength when swollen. 【0073】 [Example 5] An opening member for providing through holes in the second nonwoven fabric has an opening area of ​​10.0 mm ２ / piece, number of openings: 25 / 6.45 cm ２ An absorber was obtained in the same manner as in Example 1, except that the perforated member was changed to the one shown. The rigidity of this absorber was 65 mm, and the absorber strength when swollen was 130 times, demonstrating both flexibility and excellent absorber strength when swollen. 【0074】 [Example 6] An opening member for providing a through hole in the second nonwoven fabric has an opening area of ​​4.0 mm ２ / piece, number of openings: 10 / 6.45 cm ２An absorber was obtained in the same manner as in Example 1, except that the perforated member was changed to the one shown. The rigidity of this absorber was 70 mm, and the absorber strength when swollen was 150 times, demonstrating both flexibility and excellent absorber strength when swollen. 【0075】 [Example 7] An opening member for providing a through hole in the second nonwoven fabric has an opening area of ​​4.0 mm ２ / piece, number of openings: 75 / 6.45 cm ２ An absorber was obtained in the same manner as in Example 1, except that the perforated member was changed to the one shown. The rigidity of this absorber was 65 mm, and the absorber strength when swollen was 120 times, demonstrating both flexibility and excellent absorber strength when swollen. 【0076】 [Example 8] An absorbent was obtained in the same manner as in Example 1, except that the content of short fibers A in the second nonwoven fabric was changed to 50% by mass relative to the total amount of the second nonwoven fabric, and the proportion of short fibers made of rayon in the second nonwoven fabric was changed to 50% by mass relative to the total amount of the second nonwoven fabric. The rigidity of this absorbent was 70 mm, and the absorbent strength when swollen was 320 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0077】 [Example 9] An absorbent was obtained in the same manner as in Example 1, except that the content of short fibers A in the second nonwoven fabric was changed to 15% by mass relative to the total amount of the second nonwoven fabric, and the proportion of short fibers made of rayon in the second nonwoven fabric was changed to 85% by mass relative to the total amount of the second nonwoven fabric. The rigidity of this absorbent was 64 mm, and the absorbent strength when swollen was 210 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0078】 [Example 10] An absorbent was obtained in the same manner as in Example 1, except that the content of short fibers A in the second nonwoven fabric was changed to 70% by mass relative to the total amount of the second nonwoven fabric, and the proportion of short fibers made of rayon in the second nonwoven fabric was changed to 30% by mass relative to the total amount of the second nonwoven fabric. The rigidity of this absorbent was 80 mm, and the absorbent strength when swollen was 370 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0079】[Example 11] An absorbent was obtained in the same manner as in Example 1, except that the content of short fibers A in the second nonwoven fabric was changed to 10% by mass relative to the total amount of the second nonwoven fabric, and the proportion of short fibers made of rayon in the second nonwoven fabric was changed to 90% by mass relative to the total amount of the second nonwoven fabric. The rigidity of this absorbent was 62 mm, and the absorbent strength when swollen was 180 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0080】 [Example 12] An absorbent was obtained in the same manner as in Example 1, except that the content of short fibers A in the second nonwoven fabric was changed to 80% by mass relative to the total amount of the second nonwoven fabric, and the proportion of short fibers made of rayon in the second nonwoven fabric was changed to 20% by mass relative to the total amount of the second nonwoven fabric. The rigidity of this absorbent was 85 mm, and the absorbent strength when swollen was 390 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0081】 [Comparative Example 1] The second nonwoven fabric is an air-through nonwoven fabric (basis weight 50 g / m²) composed of short fibers made of polypropylene (fiber diameter: 4 μm, fiber length: 51 mm, single fiber strength: 0.01 N). ２ An absorbent was obtained in the same manner as in Example 1, except that the thickness was changed to 3.5 mm. The rigidity of this absorbent was 110 mm, and the strength of the absorbent when swollen was 500 cycles. It had excellent strength when swollen but poor flexibility. 【0082】 [Comparative Example 2] (Second Nonwoven Fabric) 70% by mass of rayon short fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) and 30% by mass of short fibers A (fiber diameter: 30 μm, fiber length: 51 mm, single fiber strength: 0.30 N) were blended using a card, opened, and then processed with a weaver to a basis weight of 40 g / m². ２ This was used to create a parallel web. The resulting parallel web was entangled with a high-pressure water jet and dried at 150°C for 3 minutes, resulting in a basis weight of 40 g / m². ２A second non-woven fabric b that is a span lace non-woven fabric was obtained. The content of the short fibers A contained in the second non-woven fabric b was 30% by mass with respect to the whole of the second non-woven fabric b. The absorber was obtained in the same manner as in Example 1 except that the second non-woven fabric was changed to the second non-woven fabric b. The stiffness and softness of this absorber was 65 mm, the absorber strength during swelling was 25 times, and it had flexibility, but was inferior in absorber strength during swelling. 【0083】 [Comparative Example 3] An aperturing member for providing through-holes in the second non-woven fabric was changed to an aperturing member having an aperturing area of 1.0 mm ２ / piece and 25 apertures / 6.45 cm ２ and an absorber was obtained in the same manner as in Example 1. The stiffness and softness of this absorber was 70 mm, the absorber strength during swelling was 70 times, and it had flexibility, but was inferior in absorber strength during swelling. 【0084】 [Comparative Example 4] An aperturing member for providing through-holes in the second non-woven fabric was changed to an aperturing member having an aperturing area of 15.0 mm ２ / piece and 25 apertures / 6.45 cm ２ and an absorber was obtained in the same manner as in Example 1. The stiffness and softness of this absorber was 63 mm, the absorber strength during swelling was 90 times, and it had flexibility, but was inferior in absorber strength during swelling. 【0085】 [Comparative Example 5] An aperturing member for providing through-holes in the second non-woven fabric was changed to an aperturing member having an aperturing area of 4.0 mm ２ / piece and 5 apertures / 6.45 cm ２ and an absorber was obtained in the same manner as in Example 1. The stiffness and softness of this absorber was 71 mm, the absorber strength during swelling was 70 times, and it had flexibility, but was inferior in absorber strength during swelling. 【0086】 [Comparative Example 6] An aperturing member for providing through-holes in the second non-woven fabric was changed to an aperturing member having an aperturing area of 4.0 mm ２ / piece and 100 apertures / 6.45 cm ２An absorber was obtained in the same manner as in Example 1, except that it was changed to a perforated member. The stiffness-flexibility of this absorber was 62 mm, the absorber strength during swelling was 70 times, and it had flexibility but was inferior in absorber strength during swelling. 【0087】 [Example 13] An absorber was obtained in the same manner as in Example 1, except that the method of providing through-holes in the second nonwoven fabric was changed from injection with high-pressure water flow to punching using a punch and die of a mold. The stiffness-flexibility of this absorber was 65 mm, the absorber strength during swelling was 150 times, and it had flexibility and was also excellent in absorber strength during swelling. In addition, the 2-A surface and 2-B surface of the second nonwoven fabric did not have protrusions with different heights. 【0088】 [Example 14] The basis weight of the first water-absorbing polymer was 50 g / m ２ , the basis weight of the second water-absorbing polymer was 200 g / m ２ and an absorber was obtained in the same manner as in Example 1, except that the ratio of the basis weight of the first water-absorbing polymer group to the basis weight of the second water-absorbing polymer group was changed to 0.25. The stiffness-flexibility of this absorber was 67 mm, the absorber strength during swelling was 180 times, and it had flexibility and was also excellent in absorber strength during swelling. 【0089】 [Example 15] The basis weight of the first water-absorbing polymer was 113 g / m ２ , the basis weight of the second water-absorbing polymer was 137 g / m ２ and an absorber was obtained in the same manner as in Example 1, except that the ratio of the basis weight of the first water-absorbing polymer group to the basis weight of the second water-absorbing polymer group was changed to 0.82. The stiffness-flexibility of this absorber was 67 mm, the absorber strength during swelling was 220 times, and it had flexibility and was also excellent in absorber strength during swelling. 【0090】 [Example 16] The basis weight of the first water-absorbing polymer was 25 g / m ２ , the basis weight of the second water-absorbing polymer was 225 g / m ２An absorbent was obtained in the same manner as in Example 1, except that the ratio of the basis weight of the first group of superabsorbent polymers to the basis weight of the second group of superabsorbent polymers was changed to 0.11. The rigidity of this absorbent was 66 mm, and the absorbent strength when swollen was 120 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0091】 [Example 17] The basis weight of the first superabsorbent polymer was 125 g / m². ２ The basis weight of the second superabsorbent polymer is 125 g / m². ２ An absorbent was obtained in the same manner as in Example 1, except that the ratio of the basis weight of the first group of superabsorbent polymers to the basis weight of the second group of superabsorbent polymers was changed to 1.00. The rigidity of this absorbent was 68 mm, and the absorbent strength when swollen was 260 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0092】 [Example 18] The basis weight of the second superabsorbent polymer was 300 g / m². ２ An absorbent was obtained in the same manner as in Example 1, except for the change made to [specific component]. The rigidity of this absorbent was 74 mm, and the absorbent strength when swollen was 205 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0093】 [Example 19] The basis weight of the second superabsorbent polymer was 350 g / m². ２ An absorbent was obtained in the same manner as in Example 1, except for the change made to [specific component]. The rigidity of this absorbent was 77 mm, and the absorbent strength when swollen was 150 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0094】 [Example 20] The basis weight of the first superabsorbent polymer was 350 g / m². ２ An absorbent was obtained in the same manner as in Example 1, except for the change made to [specific component]. The rigidity of this absorbent was 77 mm, and the absorbent strength when swollen was 130 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0095】 [Example 21] In the absorbent material, the amount of styrene-based hot melt adhesive applied to each of the two nonwoven fabric surfaces (2-A and 2-B) was 0.0 g / m². ２ (Without application) 2.0 g / m ２An absorbent was obtained in the same manner as in Example 1, except for the change made to [specific component]. The rigidity of this absorbent was 88 mm, and the absorbent strength when swollen was 230 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0096】 [Example 22] In the absorbent material, the amount of styrene-based hot melt adhesive applied to the 1-B side of the first nonwoven fabric and the 3-A side of the third nonwoven fabric was 2.0 g / m². ２ From 3.5 g / m ２ An absorbent was obtained in the same manner as in Example 1, except for the change made to [specific component]. The rigidity of this absorbent was 74 mm, and the absorbent strength when swollen was 220 times, demonstrating both flexibility and excellent absorbent strength when swollen. 【0097】 [Example 23] In the absorbent material, the amount of styrene-based hot melt adhesive applied to the 1-B side of the first nonwoven fabric and the 3-A side of the third nonwoven fabric was 2.0 g / m². ２ From 5.0 g / m ２ An absorbent was obtained in the same manner as in Example 1, except for the change made to [specific component]. The rigidity of this absorbent was 88 mm, and the strength of the absorbent when swollen was 235 times, demonstrating both flexibility and excellent strength when swollen. 【0098】 【0099】 【0100】 【0101】 【0102】Here, the absorbents of Examples 1 to 12 were compared with the absorbent of Comparative Example 1. In Examples 1 to 12, the second nonwoven fabric was composed of spunlace nonwoven fabric having multiple through-holes, whereas in Comparative Example 1, the second nonwoven fabric was composed of air-through nonwoven fabric. In air-through nonwoven fabric, the fibers are heat-fused together by hot air treatment of the formed web, resulting in point-like bonding between fibers, which in turn results in a bulky structure and poor flexibility. On the other hand, spunlace nonwoven fabric entangles fibers with a high-pressure water stream and does not use adhesives or heat, thus preserving the inherent softness of the fibers. As a result, the absorbents of Examples 1 to 12 were superior in flexibility compared to the absorbent of Comparative Example 1. Furthermore, the absorbent material of Comparative Example 1 exhibited superior absorbent strength during swelling despite lacking the second nonwoven fabric characteristics (having multiple through-holes, with an appropriate area for the through-holes, and an appropriate number of through-holes) found in the absorbent materials of Examples 1 to 12. This is presumed to be because the air-through nonwoven fabric of the second nonwoven fabric in the absorbent material of Comparative Example 1 has a low-density, bulky structure, making it easier to retain the water-absorbing polymer within the air-through nonwoven fabric. This suppresses localized stress concentration when the water-absorbing polymer swells, resulting in superior absorbent strength during swelling. 【0103】 The absorbents of Examples 1 to 12 were compared with those of Comparative Examples 2 to 6. The absorbents of Examples 1 to 12 were composed of a spunlace nonwoven fabric in which the second nonwoven fabric had multiple through-holes, with an appropriate area and number of through-holes. In contrast, the absorbents of Comparative Examples 2 to 6 were composed of a spunlace nonwoven fabric in which the second nonwoven fabric had no through-holes, or if it had through-holes, the area of ​​the through-holes was extremely small, or the number of through-holes was extremely small. As a result, the absorbent strength of the absorbents of Examples 1 to 12 when swollen was superior to that of the absorbents of Comparative Examples 2 to 6 when swollen. 【0104】 The absorbent material of the present invention is flexible and also exhibits excellent absorbent strength when swollen, making it suitable for use in various sanitary material products such as tape-type disposable diapers, pant-type disposable diapers, sanitary napkins, and urine absorption pads. 【0105】 1: First nonwoven fabric 2: Second nonwoven fabric 3: Third nonwoven fabric 4: Through hole 5: Adhesion area between the second nonwoven fabric and the first nonwoven fabric 6: Anchor effect of the superabsorbent polymer on the second nonwoven fabric 10: Absorbent material 21: First superabsorbent polymer group 22: Second superabsorbent polymer group 1-A: Outer surface of the first nonwoven fabric 1-B: Surface of the first nonwoven fabric facing the first superabsorbent polymer group, or the surface facing the second nonwoven fabric 2-A: Surface of the second nonwoven fabric facing the first superabsorbent polymer group, or the surface facing the first nonwoven fabric 2-B: Surface of the second nonwoven fabric facing the second superabsorbent polymer group, or the surface facing the third nonwoven fabric 3-A: Surface of the third nonwoven fabric facing the second superabsorbent polymer group, or the surface facing the second nonwoven fabric 3-B: Outer surface of the third nonwoven fabric

Claims

1. An absorbent comprising, in this order, a first nonwoven fabric, a first group of superabsorbent polymers, a second nonwoven fabric, a second group of superabsorbent polymers, and a third nonwoven fabric, wherein the second nonwoven fabric has a plurality of through holes, and the area of ​​each through hole is 1.5 to 10.0 mm². ２ It is within the range of 6.45 cm on each side of both sides of the second nonwoven fabric. ２ An absorbent having 10 to 75 through holes within a certain range.

2. The absorbent material according to claim 1, wherein a portion of the second nonwoven fabric is in contact with a portion of the first nonwoven fabric and a portion of the third nonwoven fabric.

3. The absorbent according to claim 1 or 2, wherein the 1-B surface of the first nonwoven fabric, which is the second nonwoven fabric side, the 2-A surface of the second nonwoven fabric, the 2-B surface of the second nonwoven fabric, which is the third nonwoven fabric side, and the 3-A surface of the third nonwoven fabric, which is the second nonwoven fabric side, satisfy at least one of the following conditions I and II. <Condition I> The 2-A surface has a plurality of protrusions of different heights, and at least some of the protrusions are in close contact with the 1-B surface via a hot melt adhesive. <Condition II> The 2-B surface has a plurality of protrusions of different heights, and at least some of the protrusions are in close contact with the 3-A surface via a hot melt adhesive.

4. The absorbent material according to any one of claims 1 to 3, wherein the 2-A surface, which is the first nonwoven side of the second nonwoven fabric, and the 2-B surface, which is the third nonwoven side of the second nonwoven fabric, satisfy at least one of the following conditions III and IV. <Condition III> There is no hot melt adhesive between the first superabsorbent polymer group and the 2-A surface, or the basis weight is 0.001 to 1 g / m². ２ The presence of hot melt adhesive <Condition IV> There is no hot melt adhesive between the second group of superabsorbent polymers and the 2-B surface, or the basis weight is 0.001 to 1 g / m² ２ There is a hot melt adhesive available.

5. The absorbent according to any one of claims 1 to 4, wherein the second nonwoven fabric contains short fibers A having a single fiber strength of 0.15 N or more, and the content of the short fibers A is 15 to 70% by mass of the entire second nonwoven fabric.

6. The basis weight of the first group of superabsorbent polymers is 300 g / m². ２ The following applies, and the basis weight of the second group of superabsorbent polymers is 300 g / m². ２ The absorbent material according to any one of claims 1 to 5, wherein the ratio of the basis weight of the first superabsorbent polymer group to the basis weight of the second superabsorbent polymer group (basis weight of the first superabsorbent polymer group / basis weight of the second superabsorbent polymer group) is 0.43 or more and 0.67 or less.

7. The absorbent material according to any one of claims 1 to 6, wherein the rigidity of the absorbent material is 90 mm or less.

8. The first non-woven fabric, the second non-woven fabric, and the third non-woven fabric are all spunlace non-woven fabrics, and there is a basis weight of 0.5 g / m ２ or more and 5.0 g / m ２ or less of a hot melt adhesive present on the 1-B surface, which is the surface of the first non-woven fabric on the side of the second non-woven fabric, and there is a basis weight of 0.5 g / m ２ or more and 5.0 g / m ２ or less of a hot melt adhesive present on the 3-A surface, which is the surface of the third non-woven fabric on the side of the second non-woven fabric. The absorber according to any one of claims 1 to 7.

9. A sanitary material product comprising an absorbent according to any one of claims 1 to 8.

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