Absorber and sanitary material product

Abstract

The present invention addresses the problem of providing: an absorbent body which is thin and which has excellent absorption characteristics due to high effective utilization efficiency of an absorbent polymer disposed between non-woven fabrics; and a sanitary material product. An absorbent body and a sanitary material product including the same, the absorbent body including a fibrous layer, a first non-woven fabric, a first water-absorbent polymer group, a second non-woven fabric, a second water-absorbent polymer group, and a third non-woven fabric in this order, and having a thickness of 7.0 mm or less, the fibrous layer, the first non-woven fabric, the first water-absorbing polymer group, the second non-woven fabric, the third non-woven fabric, and the second water-absorbing polymer group have various characteristics.

Description

Technical Field

[0001] The present invention relates to an absorber and a sanitary material product. Background Art

[0002] Sanitary material products such as disposable diapers or sanitary napkins have a sheet-shaped absorber that absorbs and retains aqueous liquids such as urine or menstrual blood (hereinafter sometimes referred to as urine, etc.), a topsheet disposed on one surface of the absorber, and a backsheet disposed on the other surface of the absorber. The topsheet has permeability to urine, etc., and the backsheet has leakage prevention properties against urine, etc. In addition, the absorber is configured such that a mixture of pulp fibers and a water-absorbing polymer is wrapped with a nonwoven fabric or a tissue paper.

[0003] Moreover, in a sanitary material product, when the sanitary material product is worn, the absorber, the topsheet, and the backsheet are arranged in this order from the side closer to the wearer: the topsheet, the absorber, and the backsheet.

[0004] Here, in recent years, with the spread of sanitary material products such as disposable diapers or sanitary napkins, it is desired to improve the wearing comfort by thinning the sanitary material product. In particular, since the amount of urine, etc. in adult sanitary material products is larger than that in baby products, the thickness of the absorber inevitably increases, and thus there is a high demand for further thinning.

[0005] Therefore, as a thin absorber, an absorber configured in the order of a first nonwoven fabric containing a water-absorbing polymer, a fibrous layer containing pulp fibers and a water-absorbing polymer is known (for example, refer to Patent Document 1). In addition, as a thin absorber, an absorber configured in the order of a fibrous layer containing pulp fibers and a water-absorbing polymer, a first nonwoven fabric, and a first water-absorbing polymer group is known (for example, refer to Patent Document 2).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-237449

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-68813 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] However, the present inventors et al. have found that the prior absorbers have the following problems. As described above, the absorber described in Patent Document 1 is an absorber configured in the order of a first nonwoven fabric containing a water-absorbing polymer, a fibrous layer containing pulp fibers and a water-absorbing polymer. However, in the structure where the first nonwoven fabric containing a water-absorbing polymer is disposed on the upper part, when the amount of urine or the like is large, if the water-absorbing polymer contained in the first nonwoven fabric absorbs urine or the like and swells, it hinders the penetration of urine or the like into the fibrous layer disposed in the lower part. As a result, there is a problem that the overall absorption characteristics of the absorber are insufficient.

[0012] In addition, as described above, the absorber described in Patent Document 2 is an absorber configured in the order of a fibrous layer containing pulp fibers and a water-absorbing polymer, a first nonwoven fabric, and a first water-absorbing polymer group. However, in the absorber, no consideration is given to the relationship between the liquid diffusibility of each of the first layer formed of the first nonwoven fabric and the first water-absorbing polymer group and the second layer formed of the third nonwoven fabric and the second water-absorbing polymer group, which are disposed below the fibrous layer, and the liquid diffusibility of the second nonwoven fabric. There is a problem that the overall absorption characteristics of the absorber are insufficient.

[0013] Therefore, in view of the above circumstances, the subject of the present invention is to provide an absorber and a sanitary material product that are thin, particularly in adult sanitary material products that require absorption of a large amount of urine or the like, and have excellent absorption characteristics due to high effective utilization efficiency of the water-absorbing polymer disposed between nonwoven fabrics.

[0014] Means for Solving the Problem

[0015] Regarding the present invention, in order to solve the above problems, the absorber and the sanitary material product of the present invention are as follows.

[0016] That is,

[0017] (1) An absorber, sequentially including a fibrous layer, 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, and having a thickness of 7.0 mm or less. In the absorber,

[0018] the density of the fibrous layer is 30 kg / m 3 ~100 kg / m 3 , and the thickness is 5.0 mm or less.

[0019] The fibrous layer contains pulp fibers and a water-absorbing polymer.

[0020] The particle size of the water-absorbing polymer is 200 μm to 1000 μm.

[0021] The content ratio of the pulp fibers to the water-absorbing polymer (mass of pulp fibers contained / mass of water-absorbing polymer contained) is 1.0 to 6.0.

[0022] The first non-woven fabric and the first water-absorbent polymer group form a first layer.

[0023] The third non-woven fabric and the second water-absorbent polymer group form a second layer.

[0024] The first water-absorbent polymer group is directly or indirectly fixed to the first non-woven fabric.

[0025] The second water-absorbent polymer group is directly or indirectly fixed to the third non-woven fabric.

[0026] The second non-woven fabric contains 60% by mass or more of hydrophilic fibers with respect to the whole of the second non-woven fabric.

[0027] The liquid diffusion area of the first layer is 40 cm 2 ~90 cm 2 ,

[0028] The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer is 1.1 to 2.0.

[0029] The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer is 1.1 to 2.5.

[0030] (2) Preferably, the absorbent body according to (1), wherein the hydrophilic fiber is a rayon fiber.

[0031] (3) Preferably, the absorbent body according to (1) or (2), wherein the basis weight of the second non-woven fabric is 20 g / m 2 ~50 g / m 2 .

[0032] (4) Preferably, the absorbent body according to any one of (1) to (3), wherein the first non-woven fabric contains short fiber A having a single fiber strength of 0.15 N or more.

[0033] The content of the short fiber A is 5% by mass to 40% by mass with respect to the whole of the first non-woven fabric.

[0034] (5) Preferably, the absorbent body according to any one of (1) to (4), wherein the basis weight of the first water-absorbent polymer group is 50 g / m 2 ~400 g / m 2 .

[0035] (6) Preferably, the absorbent body according to any one of (1) to (5), wherein the saturation absorption amount of the water-absorbent polymer contained in the second water-absorbent polymer group is 25 g / g to 70 g / g.

[0036] (7) Preferably, it is a sanitary material product including an absorber according to any one of (1) to (6).

[0037] Effects of the Invention

[0038] According to the present invention, an absorber and a sanitary material product that are thin and have excellent absorption characteristics can be provided. Detailed Description of the Invention

[0039] Hereinafter, the actual state of the present invention will be described in detail.

[0040] The absorber of the present invention is an absorber that sequentially includes a fibrous layer, a first non-woven fabric, a first water-absorbing polymer group, a second non-woven fabric, a second water-absorbing polymer group, and a third non-woven fabric, and has a thickness of 7.0 mm or less. The density of the fibrous layer is 30 kg / m 3 ~100 kg / m 3 , and the thickness is 5.0 mm or less. The fibrous layer contains pulp fibers and a water-absorbing polymer, and the particle size of the water-absorbing polymer is 200 μm to 1000 μm. The content ratio of the pulp fibers to the water-absorbing polymer (mass of pulp fibers contained / mass of water-absorbing polymer contained) is 1.0 to 6.0. The first non-woven fabric and the first water-absorbing polymer group form a first layer, and the third non-woven fabric and the second water-absorbing polymer group form a second layer. The first water-absorbing polymer group is directly or indirectly fixed to the first non-woven fabric, and the second water-absorbing polymer group is directly or indirectly fixed to the third non-woven fabric. The second non-woven fabric contains 60% by mass or more of hydrophilic fibers with respect to the whole of the second non-woven fabric. The liquid diffusion area of the first layer is 40 cm 2 ~90 cm 2 . The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer is 1.1 to 2.0. The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer is 1.1 to 2.5. Moreover, the absorber of the present invention having all these characteristics is a thin absorber with excellent absorption characteristics.

[0041] Regarding the mechanism by which the above effects can be obtained, the speculation is as follows. That is, the absorber of the present invention has the above-described characteristics. By disposing such an absorber with the fibrous layer side facing the wearer side of the sanitary material product, liquids such as urine penetrate into the absorber from the fibrous layer side of the absorber and travel inside the absorber in the order of the fibrous layer, the first layer, the second non-woven fabric, and the second layer. In the absorber having such a structure, the absorption characteristics of the absorber of the present invention are excellent by making the liquid diffusion area of the second non-woven fabric larger than the liquid diffusion area of the first layer or the liquid diffusion area of the second layer. Here, the larger the value of the liquid diffusion area of the layer or non-woven fabric, the more excellent the liquid diffusibility of the layer or non-woven fabric. In addition, the liquid diffusibility of the layer or non-woven fabric is in a trade-off relationship with the liquid absorption amount per unit passing time of the layer or non-woven fabric. Here, the liquid absorption amount per unit passing time refers to the amount of liquid that the layer or non-woven fabric can absorb during the period when liquids such as urine penetrate through the layer or non-woven fabric.

[0042] Specifically, liquid entering the fibrous layer of the absorbent body quickly reaches the first layer, diffuses to a certain extent within the first layer in the surface direction, and is simultaneously absorbed to a certain extent by the first layer. The fibrous layer has an appropriate density and thickness to facilitate liquid entry. The absorbent polymer particle size is optimized, and the absorbent polymer content is either equal to or less than the pulp fiber content, resulting in the absorbent polymer tending to be dispersed within the pulp fibers within the fibrous layer. Consequently, liquid transferred from the fibrous layer to the first layer flows relatively perpendicularly along the pulp fibers within the fibrous layer. The liquid is absorbed to a certain extent by the absorbent polymer dispersed within the pulp fibers, and is subsequently diffused in the surface direction of the fibrous layer by the pulp fibers and the absorbent polymer. Furthermore, gel blocking of the absorbent polymer within the fibrous layer is suppressed. Furthermore, by optimizing the absorbent polymer particle size, gel blocking of the absorbent polymer is suppressed, and the utilization efficiency of the absorbent polymer is improved. As a result, liquid rapidly reaches the first layer from the fibrous layer. Specifically, because the liquid diffuses to a certain extent in the in-plane direction through the fibrous layer, liquid transfer from the fibrous layer to the first layer occurs over a wide area of the first layer. The so-called gel blocking phenomenon is known as the phenomenon in which, when a dense concentration of water-absorbent polymers comes into contact with urine or other substances, the swelled water-absorbent polymers come into contact with each other, hindering the contact of other unabsorbed, unswelled water-absorbent polymers with the aqueous liquid. Furthermore, much of the liquid not absorbed by the first layer reaches the second nonwoven fabric, where it diffuses widely within the second nonwoven fabric in the in-plane direction. Furthermore, much of the liquid not absorbed by the second nonwoven fabric transfers to the second layer, with the remainder transferring to the first layer. Here, liquid transferred from the second nonwoven fabric to the first or second layer transfers after fully diffusing within the second nonwoven fabric, so the transfer occurs over a wide area of the first or second layer. Therefore, even if the liquid diffusivity of the first or second layer is lower than that of the second nonwoven fabric, the transferred liquid reaches the entire in-plane spreading water-absorbent polymer group in the first or second layer in a roughly even manner. Here, even if gel blocking occurs due to swelling in the first water-absorbing polymer group of the first layer, liquid will flow around the gel-blocking portion, spreading in a circular pattern and transferring to the fibrous layer, where it will also be absorbed by the pulp fibers and water-absorbing polymer within the fibrous layer. Therefore, the water-absorbing polymers in the fibrous layer, the first layer, and the second layer can be efficiently utilized. Furthermore, in this case, since the liquid diffusivity of the first or second layer can be lower than that of the second nonwoven fabric, the amount of liquid absorbed per unit time by the first or second layer can be increased.

[0043] Furthermore, by providing a fibrous layer having the specific structure described above on top of a laminate comprising a first layer, a second nonwoven fabric, and a second layer, the amount of liquid absorbed is superior to that achieved by employing a structure comprising the first layer, a second nonwoven fabric, and a second layer. Specifically, since liquid such as urine that reaches the fibrous layer of the absorbent body is prevented from remaining on the surface of the fibrous layer or flowing back, it rapidly penetrates the fibrous layer and then diffuses to a certain extent in the plane of the fibrous layer, transferring the liquid from the fibrous layer to the first layer over a wide area. This improves the utilization efficiency of the water-absorbing polymer contained in the absorbent body, resulting in a superior amount of liquid absorbed by the absorbent body compared to a structure comprising the first layer, a second nonwoven fabric, and a second layer. Furthermore, by providing a fibrous layer having the specific structure described above on top of a laminate comprising the first layer, a second nonwoven fabric, and a second layer, the absorption position of the absorbent body is superior to that achieved by employing a structure comprising the first layer, a second nonwoven fabric, and a second layer.

[0044] The absorbent core of the present invention can absorb a large amount of liquid by having these characteristics, that is, it has excellent absorption properties.

[0045] Here, in the first and second layers, the absorbent polymer group is directly or indirectly fixed to the first or second nonwoven fabric. Therefore, the amount of absorbent polymer present within the second nonwoven fabric in the absorbent core can be minimized. As a result, the second nonwoven fabric maintains high liquid diffusivity.

[0046] Furthermore, the fact that the second nonwoven fabric contains 60% by mass or more of hydrophilic fibers relative to the entire second nonwoven fabric also contributes to improving the liquid diffusibility of the second nonwoven fabric.

[0047] As described above, since the absorbent body of the present invention has high absorption characteristics, it is possible to form a thin absorbent body with a thickness of 7.0 mm or less.

[0048] (Fiberous layer)

[0049] The fibrous layer included in the absorbent body of the present invention is described below. The density of the fibrous layer is 30 kg / m 3 ~100kg / m 3 The fibrous layer contains pulp fibers and water-absorbing polymers, has a thickness of less than 5.0 mm, a particle size of the water-absorbing polymer is 200 μm to 1000 μm, and a content ratio of pulp fibers to water-absorbing polymers (mass content of pulp fibers / mass content of water-absorbing polymers) is 1.0 to 6.0.

[0050] The fibrous layer has a moderate density and thickness that allows liquids to easily penetrate into its interior, which results in an appropriate particle size of the water-absorbent polymer. Furthermore, the content of the water-absorbent polymer is the same as that of the pulp fibers, or the content of the water-absorbent polymer is less than that of the pulp fibers but is an appropriate amount. Inside the fibrous layer, the absorbent polymer tends to be dispersed among the pulp fibers. As a result, the liquid transferred from the fibrous layer to the first layer flows along the pulp fibers in the vertical direction within the fibrous layer and is absorbed to a certain extent by the water-absorbent polymer dispersed among the pulp fibers, and then is diffused by the pulp fibers and the water-absorbent polymer in the plane direction of the fibrous layer. On the other hand, the gel blockage phenomenon of the water-absorbent polymer in the fibrous layer can be suppressed. Furthermore, by making the particle size of the water-absorbent polymer appropriate, the gel blockage phenomenon of the water-absorbent polymer can be suppressed, and the utilization efficiency of the water-absorbent polymer can be improved. As a result, the liquid quickly reaches the first layer from the fibrous layer. That is, since the liquid diffuses to a certain extent in the plane direction of the fibrous layer through the fibrous layer, the transfer of the liquid from the fibrous layer to the first layer occurs in a wide area of the first layer.

[0051] Here, the density of the fibrous layer is set to 30 kg / m 3 ~100 kg / m 3 , the fibrous layer contains pulp fibers and a water-absorbent polymer, has a thickness of 5.0 mm or less, the particle size of the water-absorbent polymer is 200 μm to 1000 μm, and the content ratio of the pulp fibers to the water-absorbent polymer (mass of pulp fibers contained / mass of water-absorbent polymer contained) is set to 1.0 to 6.0. Thus, adjustments such as the following can be made: the liquid can flow in the vertical direction within the fibrous layer through the pulp fibers in the fibrous layer, or the liquid can be diffused in the plane direction of the fibrous layer by the pulp fibers and the water-absorbent polymer in sequence, the gel blockage phenomenon of the water-absorbent polymer in the fibrous layer can be suppressed, the utilization efficiency of the water-absorbent polymer in the fibrous layer can be improved, the water-absorbent polymer can be fixed in the pulp fibers and shedding can be suppressed, and the reduction of the absorption speed of the entire absorber can be suppressed. As a result, the absorption characteristics of the entire absorber can be excellent.

[0052] By setting the density of the fibrous layer to 100 kg / m 3 or less, the reduction in softness that affects the wearing feeling of the sanitary material product can also be suppressed. From the viewpoint of obtaining the above effects, the density of the fibrous layer is preferably 40 kg / m 3 or more, and preferably 80 kg / m 3 or less.

[0053] In addition, the thickness of the fibrous layer is preferably 4.0 mm or less. On the other hand, for the reason of making the absorption characteristics of the absorber more excellent, the thickness of the fibrous layer is preferably 1.0 mm or more. The thickness of the fibrous layer mentioned here refers to the value measured based on the method of JIS L1913 (1998) 6.1.2A.

[0054] In addition, the content ratio of the pulp fiber to the water-absorbing polymer (mass of pulp fiber contained / mass of water-absorbing polymer contained) is preferably 2.0 or more and preferably 4.0 or less. The content ratio of the pulp fiber to the water-absorbing polymer in the fibrous layer refers to the value measured by the method described in the measurement method item of the examples.

[0055] In addition, as the raw material of the pulp fiber contained in the fibrous layer, raw materials including cellulose fiber, rayon, and tow fibers such as acetate can be cited. One kind can be used alone, or two or more kinds can be mixed and used. Here, as the wood that is the extraction source of cellulose fiber, broad-leaved trees or coniferous trees can be cited. For the reason of excellent strength or water absorbency, the wood that is the extraction source of cellulose fiber is preferably coniferous trees.

[0056] From the viewpoints of strength or water absorbency, the average fiber length of the pulp fiber contained in the fibrous layer is preferably 1 mm to 5 mm.

[0057] In addition, as the water-absorbing polymer contained in the fibrous layer, for example, starch or crosslinked carboxymethylated cellulose, polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid, polyacrylates such as sodium polyacrylate, or polyacrylate graft polymers can be cited. Among these, from the viewpoint of productivity, sodium polyacrylate is preferred.

[0058] (First nonwoven fabric - Third nonwoven fabric)

[0059] The first nonwoven fabric - third nonwoven fabric included in the absorber of the present invention will be described.

[0060] Here, as the fibers constituting the first nonwoven fabric - third nonwoven fabric, olefin fibers such as polyethylene fibers and polypropylene fibers, polyester fibers such as polyethylene terephthalate fibers, polytrimethylene terephthalate fibers, and polybutylene terephthalate fibers, acrylic fibers such as nylon fibers and acrylonitrile fibers, and cellulose-based fibers such as cotton, hemp, and rayon fibers can be cited. Among these, cellulose-based fibers such as cotton, hemp, and rayon fibers, which are hydrophilic fibers, are preferred, and rayon fibers, which have excellent liquid diffusibility for urine and the like and are easily fibrillated, are more preferred. In addition, from the viewpoint of the liquid diffusibility of urine and the like, each of the first nonwoven fabric - third nonwoven fabric preferably contains 50% by mass or more of rayon fibers with respect to the whole of each nonwoven fabric.

[0061] The unit area weight of the first non-woven fabric to the third non-woven fabric is preferably 20 g / m 2 - 50 g / m 2 . For the reasons that the unevenness of the unit area weight of the non-woven fabric can be reduced to reliably carry the water-absorbing polymer, and the liquid diffusibility of urine and the like into the non-woven fabric can be improved by increasing the number of fibers, the unit area weight of the first non-woven fabric to the third non-woven fabric is more preferably 30 g / m 2 or more. On the other hand, for the reason that the reduction of the water permeability of urine and the like into the non-woven fabric can be suppressed, the unit area weight of the first non-woven fabric to the third non-woven fabric is more preferably 45 g / m 2 or less.

[0062] In addition, as the types of the first non-woven fabric to the third non-woven fabric, specifically, thermally bonded non-woven fabric, spunbond non-woven fabric, and hydroentangled non-woven fabric can be mentioned. Among these, for the reason that non-woven fabric formation can be achieved without using an adhesive and the risk of foreign matters such as needles being mixed in can be suppressed, which is more suitable for sanitary materials, the type of the first non-woven fabric to the third non-woven fabric is preferably hydroentangled non-woven fabric.

[0063] In addition, the first non-woven fabric to the third non-woven fabric of the absorbent body of the present invention may be the same or different from each other.

[0064] (First non-woven fabric)

[0065] The first non-woven fabric used in the absorbent body of the present invention will be described in detail.

[0066] Here, the first nonwoven fabric is arranged on the surface sheet side of the sanitary material, quickly absorbs urine, etc., diffuses the urine, etc. absorbed by the first nonwoven fabric, and increases the water absorption capacity of the first water-absorbing polymer group. In terms of improving water permeability, the first nonwoven fabric preferably contains short fibers A with a single fiber strength of 0.15N or more, preferably containing 5% to 40% by mass of short fibers A relative to the entire first nonwoven fabric. The so-called short fibers are fibers with a fiber length within the range of 10mm to 100mm. From the perspective of passability in a carding machine described later, the fiber length of the short fibers A is more preferably 20mm to 80mm. The so-called single fiber strength of the short fibers is the maximum load of the elongation-load curve obtained when a single short fiber is subjected to a tensile test. More specifically, it refers to the value measured using the method described in the section on the measurement method in the examples. During the production of the first nonwoven fabric, even if a process such as water spraying or calendering is performed that applies a force in the planar direction to the staple fibers, the repulsion caused by the rigidity of the staple fibers tends to orient the fiber axes of the entire first nonwoven fabric in the thickness direction. This increases the bulk of the nonwoven fabric and the interstices within the nonwoven fabric, resulting in an accelerated absorption rate of urine, etc., into the first nonwoven fabric. For this reason, the first nonwoven fabric more preferably contains 10% by mass or more of the staple fibers A relative to the entire first nonwoven fabric. On the other hand, to prevent a decrease in the diffusibility of urine, etc. into the first nonwoven fabric or a decrease in the softness that affects the wearing feel of sanitary products, the first nonwoven fabric more preferably contains 35% by mass or less of the staple fibers A relative to the entire first nonwoven fabric.

[0067] Examples of the raw materials for the staple fibers A include polyolefin staple fibers such as polyethylene and polypropylene, polyester staple fibers such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, polyamide staple fibers, and acrylic fibers such as acrylonitrile. Among these staple fibers, polyester staple fibers and polyamide staple fibers are preferred due to their excellent strength, handleability, and productivity. Furthermore, polyethylene terephthalate staple fibers and nylon 6 or nylon 66 staple fibers are more preferred.

[0068] The short fibers A are preferably hollow fibers. By forming hollow fibers, the short fibers A themselves become larger, making it easier to orient the fiber axes of the entire first nonwoven fabric in the thickness direction, thereby accelerating the absorption rate of the first nonwoven fabric and improving the absorption properties of the absorbent.

[0069] The first nonwoven fabric preferably contains 60% to 95% by mass of rayon fibers relative to the total mass of the first nonwoven fabric. Because of the excellent diffusion of liquids such as urine into the nonwoven fabric, the first nonwoven fabric more preferably contains 65% or more by mass of rayon fibers relative to the total mass of the first nonwoven fabric. Furthermore, because the combination with the aforementioned short fibers A having a density of 0.15N or greater can enhance water permeability, the first nonwoven fabric more preferably contains 90% or less by mass of rayon fibers relative to the total mass of the first nonwoven fabric.

[0070] (Second non-woven fabric)

[0071] Next, the second nonwoven fabric used in the absorbent core of the present invention will be described in detail. The second nonwoven fabric contains 60% by mass or more of hydrophilic fibers based on the entire second nonwoven fabric.

[0072] Here, the second nonwoven fabric is arranged between the first nonwoven fabric and the third nonwoven fabric. By further taking into account the liquid diffusibility and water permeability of urine, etc. in the second nonwoven fabric, the water absorption of the water-absorbing polymer on the first nonwoven fabric side is increased, and the effective utilization efficiency of the water-absorbing polymer on the first nonwoven fabric side is improved. Moreover, by allowing urine, etc. to permeate to the third nonwoven fabric side, the water-absorbing polymer on the third nonwoven fabric side can be effectively utilized, and the absorption characteristics of the absorbent body are excellent. From the perspective of achieving the above effect, the second nonwoven fabric contains 60% or more of hydrophilic fibers relative to the entire second nonwoven fabric, preferably 80% or more, and more preferably 95% or more. From the perspective of achieving the above effect, the unit weight of the second nonwoven fabric is preferably 20 g / m 2 ~50g / m 2 .

[0073] Furthermore, the three-dimensional arithmetic mean roughness of at least one surface of the second nonwoven fabric is preferably between 50 μm and 300 μm. The three-dimensional arithmetic mean roughness is a three-dimensional expansion of the surface roughness parameter from two dimensions. More specifically, it refers to the value measured using the method described in the section "Measurement Methods" in the Examples. To prevent uneven placement of the water-absorbing polymer on the nonwoven fabric, the three-dimensional arithmetic mean roughness of at least one surface of the second nonwoven fabric is more preferably 80 μm or greater. On the other hand, to improve the diffusivity of liquids such as urine in the planar direction by smoothing the surface, the three-dimensional arithmetic mean roughness of at least one surface of the second nonwoven fabric is more preferably 200 μm or less. Methods for achieving the three-dimensional arithmetic mean roughness of at least one surface of the second nonwoven fabric within the above range include adjusting the type of fibers constituting the nonwoven fabric, the basis weight of the nonwoven fabric, the type of nonwoven fabric, the interlacing conditions during the nonwoven fabric formation, the web production method, the type of adhesive, and the amount of adhesive used.

[0074] (Third non-woven fabric)

[0075] The third nonwoven fabric used in the absorber of the present invention will be described in detail. The third nonwoven fabric further diffuses urine or the like that has passed through the second nonwoven fabric by using the third nonwoven fabric, thereby increasing the absorption amount in the second water-absorbing polymer group. From the viewpoint of obtaining the above-described effects, the third nonwoven fabric preferably contains 80% by mass or more of rayon fibers based on the entire third nonwoven fabric, and more preferably contains 95% by mass or more. When the content of the hydrophilic rayon fibers is increased, the liquid diffusibility of urine or the like into the nonwoven fabric becomes good.

[0076] (Method for manufacturing the first to third nonwoven fabrics)

[0077] Next, a method for manufacturing the first to third nonwoven fabrics used in the absorber of the present invention will be specifically described, but the method for manufacturing the first to third nonwoven fabrics used in the absorber of the present invention is not limited to these. In addition, the methods for manufacturing the first to third nonwoven fabrics may also be different from each other.

[0078] The staple fibers for obtaining the first to third nonwoven fabrics of the present invention are put into a carding machine, and after fiber blending and fiber opening, a uniform web is formed by a lapping machine. When the first to third nonwoven fabrics of the present invention are spunlace nonwoven fabrics, the web is then put into a water jet nonwoven fabric forming device, and is intertwined by high-pressure water flow to form a nonwoven fabric. Then, the nonwoven fabric is dried by a hot air oven to obtain a spunlace nonwoven fabric.

[0079] In addition, for the reason of improving the utilization efficiency of the water-absorbing polymer by increasing the liquid diffusibility of urine or the like in the length direction in a rectangular absorber, the web is preferably a parallel web in which the constituent fibers are oriented in the length direction or a crisscross web including a parallel web in which the constituent fibers are oriented in the length direction. In the nonwoven fabric obtained from these webs, the fiber orientation degree of the constituent fibers in the length direction becomes high. In addition, the crisscross web is a web formed by laminating a parallel web in which the parallel web is oriented in the short side direction through a cross layer or the like and a parallel web.

[0080] (First water-absorbing polymer group and second water-absorbing polymer group)

[0081] The absorber of the present invention includes a first water-absorbing polymer group and a second water-absorbing polymer group (hereinafter sometimes simply referred to as "water-absorbing polymer group"). The water-absorbing polymer group contains a water-absorbing polymer.

[0082] Examples of the water-absorbing polymer used in the present invention include: starch or crosslinked carboxymethylated cellulose, polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid, polyacrylates such as sodium polyacrylate, or polyacrylate graft polymers. Among these, from the viewpoint of productivity, sodium polyacrylate is preferred.

[0083] In addition, from the perspective of operability in manufacturing processes and the like, the water-absorbing polymer is preferably in the form of particles. When the water-absorbing polymer is in the form of particles, its particle size is preferably 150 μm to 850 μm. More specifically, the particle size of the water-absorbing polymer is a value measured by the method described in the items of the measurement method in the examples. Here, by setting the particle size of the water-absorbing polymer to 150 μm or more, it is possible to suppress the case where the liquid diffusibility of urine or the like in the non-woven fabric is hindered when the water-absorbing polymer penetrates into each of the first non-woven fabric to the third non-woven fabric and the penetrated water-absorbing polymer swells upon absorbing urine or the like. On the other hand, by setting the particle size of the water-absorbing polymer to 850 μm or less, it is possible to suppress a decrease in the water absorption capacity of the water-absorbing polymer.

[0084] The unit area weight of the first water-absorbing polymer group and the second water-absorbing polymer group is preferably 50 g / m 2 ~400 g / m 2 . For the reason that the urine absorption amount of the absorbent body can be increased, the unit area weight of the first water-absorbing polymer group and the second water-absorbing polymer group is more preferably 100 g / m 2 or more. On the other hand, for the reason that it is possible to suppress a decrease in air permeability when used in sanitary material products or the water-absorbing polymer that has absorbed urine or the like leaks from the absorbent body due to its weight, the unit area weight of the first water-absorbing polymer group and the second water-absorbing polymer group is more preferably 300 g / m 2 or less.

[0085] In addition, the ratio of the unit area weight of the first water-absorbing polymer group to the second water-absorbing polymer group is preferably 20:80 to 45:55. By setting the ratio of the unit area weight of the first water-absorbing polymer group to the second water-absorbing polymer group within the above range, it is possible to prevent urine or the like absorbed by the second water-absorbing polymer group from flowing back to the first water-absorbing polymer group or the second non-woven fabric and suppress the gel blockage phenomenon. As a result, the absorption characteristics of the entire absorbent body can be improved. From the above perspective, the ratio of the unit area weight of the first water-absorbing polymer group to the second water-absorbing polymer group is further preferably 30:70 to 40:60.

[0086] In addition, the gel liquid permeability of the water-absorbing polymer contained in the first water-absorbing polymer group is preferably 50 ml / min to 350 ml / min. The gel liquid permeability refers to the speed at which physiological saline passes through the water-absorbing polymer swollen and gelled by physiological saline under load. More specifically, it refers to the value measured by the method described in the measurement method item of the examples. For the reasons that the liquid diffusibility of urine and the like in the first water-absorbing polymer group can be improved, the liquid delivery amount of urine and the like to the second non-woven fabric side can be increased, and the absorption position when used in sanitary material products such as diapers can be improved, the gel liquid permeability of the water-absorbing polymer contained in the first water-absorbing polymer group is more preferably 100 ml / min or more. On the other hand, for the reason that liquid leakage of urine and the like from the first layer containing the first water-absorbing polymer group can be suppressed during the process of insufficient absorption of the first water-absorbing polymer, the gel liquid permeability of the water-absorbing polymer contained in the first water-absorbing polymer group is more preferably 250 ml / min or less.

[0087] In addition, the saturation absorption amount of the water-absorbing polymer contained in the second water-absorbing polymer group is preferably 25 g / g to 70 g / g. The saturation absorption amount is the value measured by the tea bag method specified in JIS K7223 (1996). More specifically, it refers to the value measured by the method described in the measurement method item of the examples. For the reason that the absorption characteristics of the absorber can be improved, the saturation absorption amount of the water-absorbing polymer contained in the second water-absorbing polymer group is more preferably 30 g / g or more, and further preferably 35 g / g or more. On the other hand, for the reason that the shape of the absorber cannot be maintained and the water-absorbing polymer itself leaks from the absorber can be suppressed, the saturation absorption amount of the water-absorbing polymer contained in the second water-absorbing polymer group is more preferably 60 g / g or less.

[0088] In addition, the water-absorbing polymer contained in the second water-absorbing polymer group preferably contains spherical particles or aggregates of spherical particles, and contains 60% by mass or more of spherical particles or aggregates of spherical particles based on the total water-absorbing polymer contained in the second water-absorbing polymer group. For the reasons that the delivery of liquids such as urine to the third non-woven fabric can be suppressed and the liquid leakage of urine and the like from the third non-woven fabric can be suppressed during the process of insufficient absorption of the first water-absorbing polymer or the second water-absorbing polymer, it is more preferably contains 80% by mass or more of spherical particles or aggregates of spherical particles based on the total water-absorbing polymer contained in the second water-absorbing polymer group, and further preferably contains 95% by mass or more.

[0089] (Absorber)

[0090] The absorbent body of the present invention comprises, in order, a fibrous layer, 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. With this structure, when the absorbent body of the present invention is used in sanitary products such as diapers, urine and other fluids excreted by the wearer quickly penetrate the interior of the absorbent body and are rapidly absorbed by the water-absorbing polymers, retaining the fluid. Consequently, sanitary products can be manufactured that provide minimal discomfort when worn and minimize leakage of fluids such as urine.

[0091] Here, the thickness of the absorbent body of the present invention is 7.0 mm or less. When the thickness of the absorbent body is 7.0 mm or less, when the absorbent body of the present invention is used in sanitary products such as diapers, the sanitary products using the absorbent body of the present invention become soft, can suppress the stiffness, and further, can make the wearing feel excellent. In order to make the wearing feel of the sanitary products better, the absorbent body is preferably thin, and the thickness of the absorbent body is preferably 5.0 mm or less. On the other hand, in order to make the absorption characteristics of the absorbent body better, the thickness of the absorbent body is preferably 1.5 mm or more. In addition, the thickness of the absorbent body mentioned here refers to the value obtained by measuring based on JIS L1913 (1998) 6.1.2A method.

[0092] In the absorbent body of the present invention, the first nonwoven fabric and the first water-absorbing polymer group form the first layer, and the third nonwoven fabric and the second water-absorbing polymer group form the second layer. Furthermore, the first water-absorbing polymer group is directly or indirectly fixed to the first nonwoven fabric, and the second water-absorbing polymer group is directly or indirectly fixed to the third nonwoven fabric. Hereinafter, the "first layer formed by the first nonwoven fabric and the first water-absorbing polymer group" may be simply referred to as the "first layer." Furthermore, the "second layer formed by the third nonwoven fabric and the second water-absorbing polymer group" may be simply referred to as the "second layer." When the absorbent body of the present invention is used in a sanitary product, the first layer side serves as the skin-facing surface, and the second layer side serves as the surface opposite the skin-facing surface.

[0093] Here, the liquid diffusion area of the first layer is 40 cm 2 ~90cm 2The so-called liquid diffusion area is the diffusion area of physiological saline on the surface of the first nonwoven fabric side in the vertical direction from the first nonwoven fabric to the third nonwoven fabric of the absorbent body after 5 ml of physiological saline is passed from the surface of the first nonwoven fabric side to the other surface in the vertical direction from the first nonwoven fabric to the third nonwoven fabric. More specifically, it refers to the value measured by the method described in the item of the measurement method of the embodiment. The liquid diffusion area of the first layer is preferably 45 cm for the following reasons, namely, it can improve the liquid diffusivity of urine, etc. of the second nonwoven fabric in contact with the first layer in the absorbent body, and it can improve the efficiency of absorbing urine, etc. of the first water-absorbing polymer forming the first layer, and it can improve the absorption amount of urine, etc. of the first nonwoven fabric itself forming the first layer, so that the absorption characteristics of the absorbent body as a whole are excellent. 2 More than 50cm, more preferably 2 On the other hand, the liquid diffusion area of the first layer is more preferably 85 cm2 in order to suppress the decrease in water permeability to the second nonwoven fabric and to suppress the leakage of liquid such as urine from the first layer. 2 Below, more preferably 80cm 2 As follows. Examples of methods for achieving the liquid diffusion area of the first layer within the aforementioned range include adjusting the type of fibers constituting the first nonwoven fabric, the basis weight of the first nonwoven fabric, the type of the first nonwoven fabric, the entanglement conditions during the first nonwoven fabric formation, the method for producing the first web, the type of the first water-absorbing polymer, the particle size of the first water-absorbing polymer, the basis weight of the first water-absorbing polymer group, the gel permeation rate of the first water-absorbing polymer, the type of adhesive, and the amount of adhesive used.

[0094] Next, the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer is 1.1 to 2.0, and the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer is 1.1 to 2.5. By setting the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer to 1.1 to 2.0 and setting the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer to 1.1 to 2.5, urine and other liquids diffusing inside the second nonwoven fabric can penetrate into the first layer or the second layer, thereby improving the efficiency of the first water-absorbing polymer in the first layer or the second water-absorbing polymer in the second layer in absorbing urine and the like. Furthermore, since various adjustments such as the following can be made: leakage of urine and other liquids from the first layer during insufficient absorption by the second water-absorbing polymer in the second layer can be suppressed, and leakage of urine and other liquids from the second layer during insufficient absorption by the first water-absorbing polymer in the first layer can be suppressed, the absorption characteristics of the absorbent body can be made excellent. From the viewpoint of obtaining the above effects, the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer is preferably 1.2 or more and preferably 1.8 or less. In addition, the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer is preferably 1.4 or more and preferably 2.0 or less. Furthermore, since liquids flow downward due to gravity, the amount of liquid transferred from the second nonwoven fabric to the second layer is greater than the amount of liquid transferred from the second nonwoven fabric to the first layer. Therefore, by making the liquid diffusion area of the first layer larger than that of the second layer, the absorption characteristics of the absorbent body of the present invention become more excellent. For the above reasons, the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer is more preferably 1.3 or more and more preferably 1.5 or less. In addition, the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer is more preferably 1.6 or more and more preferably 1.8 or less. In addition, as a method for making the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer and the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer fall within the above range, examples include adjusting the type of fibers constituting the nonwoven fabric, the unit area weight of the nonwoven fabric, the type of nonwoven fabric, the interlacing conditions during nonwoven fabric formation, the method of making the web, the type of water-absorbing polymer, the particle size of the water-absorbing polymer, the unit area weight of the water-absorbing polymer group, the gel liquid permeability of the first water-absorbing polymer, the saturation absorption amount of the second water-absorbing polymer, the shape of the second water-absorbing polymer, the type of adhesive, and the amount of adhesive used.

[0095] Materials for securing the water-absorbing polymer group required to form the first and second layers to the nonwoven fabric include hot melt adhesives or heat-fusible resin powders. Suitable hot melt adhesives include styrene-based hot melt adhesives or olefin-based hot melt adhesives suitable for sanitary products. Heat-fusible resin powders, such as polyethylene powder or ethylene-vinyl acetate copolymer powder, are suitable due to their ability to be heat-fused at relatively low temperatures. Hot melt adhesives are more preferred as materials for securing the water-absorbing polymer group to the nonwoven fabric due to their low weight per unit area.

[0096] The amount of hot melt adhesive applied to each of the first and second layers is preferably 0.5 g / m 2 ~10.0g / m 2 In order to fix the water-absorbing polymer on the nonwoven fabric, the spreading amount of the hot melt adhesive is more preferably 1.0 g / m 2 On the other hand, the amount of hot melt adhesive applied is more preferably 4.0 g / m2 for the following reasons: it is possible to suppress the hindrance of the expansion of the water-absorbing polymer due to the hot melt adhesive and to suppress the hindrance of the transfer of liquid such as urine from the fibrous layer to the first layer, thereby suppressing the reduction in the absorption characteristics of the absorbent body. 2 Below, more preferably 3.0g / m 2 Below, particularly preferably 2.5 g / m 2 the following.

[0097] The absorbent body of the present invention is preferably in a substantially rectangular sheet shape, similar to absorbent bodies used in known sanitary products such as diapers.

[0098] The absorption property of the absorber of the present invention is preferably such that the absorption amount is 250 g or more. The absorption amount in the present invention refers to the weight of the physiological saline absorbed by the absorber before the physiological saline leaks from the lower side surface of the specimen in a tilted state of 45°. More specifically, it refers to the value measured by the method described in the item of the measurement method in the examples. By using the absorber in a sanitary material product, the liquid leakage prevention property is excellent, and leakage can be suppressed when the sanitary material product is in a tilted state, such as when lying down in a wearing state. From this point of view, the absorption amount of the absorber is more preferably 275 g or more, further preferably 300 g or more, and particularly preferably 325 g or more. In addition, the absorption property of the absorber of the present invention is preferably such that the absorption position of the absorber is 30 mm or less. The absorption position of the absorber refers to the distance from the dropping position of the physiological saline to the position where the physiological saline is absorbed into the absorber and disappears from the surface of the absorber when measuring the absorption amount of the absorber. More specifically, it refers to the value measured by the method described in the item of the measurement method in the examples. By using an absorber with a low absorption position value in a sanitary material product, liquid leakage can be suppressed. From this point of view, the absorption position of the absorber is more preferably 25 mm or less, and further preferably 20 mm or less. As a method for obtaining such an absorber, for example, the materials described in Example 1 etc. can be used, and the manufacturing method described in Example 1 can be adopted. In addition, by appropriately adjusting one or more selected from the group consisting of the density of the fibrous layer, the thickness of the fibrous layer, the particle size of the water-absorbing polymer contained in the fibrous layer, the content ratio of the pulp fiber and the water-absorbing polymer in the fibrous layer, the liquid diffusion area of the first layer, the liquid diffusion area of the second non-woven fabric, the liquid diffusion area of the second layer, and the content of hydrophilic fibers in the second non-woven fabric, the absorption amount of the absorber can be made within the above range.

[0099] (Manufacturing method of absorber)

[0100] The method for manufacturing the absorber of the present invention will be specifically described, but the manufacturing method of the absorber of the present invention is not limited to the following method.

[0101] First, a pulp fiber web is mixed with a water-absorbing polymer to obtain a fibrous layer. Then, a water-absorbing polymer group is fixed between the first non-woven fabric and the second non-woven fabric, and between the second non-woven fabric and the third non-woven fabric. The fibrous layer is laminated and fixed on the side surface of the first non-woven fabric to form a sheet, and an absorber is obtained.

[0102] As a method for fixing the water-absorbing polymer group, the following methods can be cited: (1) Uniformly spray or spiral a hot-melt adhesive on one surface of the third non-woven fabric; then, uniformly disperse the second water-absorbing polymer thereon; then, press-bond one surface of the second non-woven fabric thereon; then, uniformly disperse the first water-absorbing polymer on the other surface of the second non-woven fabric (the surface on which the second water-absorbing polymer is not dispersed); in addition, spray or spiral a hot-melt adhesive on one surface of the first non-woven fabric; then, press-bond the other surface of the second non-woven fabric (the surface on which the first water-absorbing polymer is dispersed) and one surface of the first non-woven fabric (the surface on which the hot-melt adhesive is dispersed); or (2) A method in which a substance obtained by previously uniformly mixing a hot-melt resin powder and the first water-absorbing polymer is dispersed on one surface of the first non-woven fabric, the second non-woven fabric is covered on the first water-absorbing polymer group, heated to a temperature above the melting point of the hot-melt powder for hot press-bonding, and then a substance obtained by previously uniformly mixing a hot-melt resin powder and the second water-absorbing polymer is dispersed on the other surface of the second non-woven fabric, the third non-woven fabric is covered on the second water-absorbing polymer group, and heated to a temperature above the melting point of the hot-melt powder for hot press-bonding.

[0103] In addition, as a method for laminating and fixing the fibrous layer on the surface on the first non-woven fabric side, a method of spraying or spiraling a hot-melt adhesive on the surface of the first non-woven fabric (the surface on which the first water-absorbing polymer is not dispersed) can be cited.

[0104] (Method for manufacturing a sanitary material product)

[0105] A method for manufacturing a sanitary material product such as a disposable diaper or a sanitary napkin using the absorbent body of the present invention will be described. For the absorbent body of the present invention cut into a rectangular shape, the absorbent body is clamped and fixed between a surface sheet and a back sheet having the same rectangular shape as the absorbent body and a larger area than the absorbent body. In addition, the surface sheet side becomes the skin-side use surface, and the back sheet becomes the surface on the opposite side of the skin-side use surface. Here, it is preferable to clamp the absorbent body using the surface sheet and the back sheet in such a manner that the fibrous layer of the absorbent body is in contact with the surface sheet. Since the fibrous layer has the characteristic of easily allowing an aqueous liquid to permeate from one surface of the fibrous layer to the other surface, the aqueous liquid that has penetrated into the surface sheet quickly permeates through the fibrous layer, and then, through the first non-woven fabric that also has the characteristic of easily allowing an aqueous liquid to permeate, and is then absorbed by the water-absorbing polymer group disposed below the fibrous layer, and is easy to retain water. Therefore, the absorption characteristics of the absorbent body can be improved. Examples of the method for fixing the portions where the surface sheet and the absorbent body, the back sheet and the absorbent body, and the surface sheet and the back sheet are in direct contact include a method using a hot melt adhesive or a method using a hot melt resin powder. In addition, as the surface sheet used when the absorbent body of the present invention is made into a sanitary material product, from the viewpoint of making the liquid permeability or the touch more excellent, it is preferable to use a non-woven fabric. For example, it is also preferable to use a wet non-woven fabric, a resin-bonded dry non-woven fabric, a heat-bonded dry non-woven fabric, a spunbonded dry non-woven fabric, a needle-punched dry non-woven fabric, a water-jet-pierced dry non-woven fabric, a flash-spun non-woven fabric, etc., and in addition, a non-woven fabric manufactured by a papermaking method that can make the basis weight per unit area or the thickness uniform. Among them, from the viewpoint of being located in contact with human skin, it is preferable to use a heat-bonded dry non-woven fabric with excellent touch as the surface sheet. In addition, as the back sheet used when the absorbent body of the present invention is made into a sanitary material product, from the viewpoint of allowing the water vapor accumulated inside the sanitary material product to be released to the outside and giving comfort to the wearer, and from the viewpoint of excellent waterproofness or touch, a laminated sheet of a moisture-permeable waterproof film and a non-woven fabric is preferable. Examples of the moisture-permeable waterproof film include a porous polyethylene film, a moisture-permeable urethane film, or a moisture-permeable polyester elastomer film. In addition, as the non-woven fabric, the same non-woven fabric as the surface sheet can be used, but from the viewpoints of cost and strength, a spunbonded dry non-woven fabric is preferable.

[0106] Examples

[0107] Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these. In addition, the performance in the examples was measured by the following methods.

[0108] [Measurement methods]

[0109] (1) Content of fibers constituting the non-woven fabric

[0110] Based on JIS L 1030-1 (2012) "Test Method for Blending Ratio of Textile Products - Part 1: Fiber Identification" and JIS L 1030-2 (2012) "Test Method for Blending Ratio of Textile Products - Part 2: Fiber Blending Ratio", the positive blending ratio (mass ratio of each fiber under standard conditions) is measured and used as the content (mass %) of the fibers constituting the nonwoven fabric.

[0111] (2) Unit area weight of the nonwoven fabric

[0112] Based on JIS L 1913 (2010) 6.2, the mass (g / m 2 ) per unit area (1 m 2 ) of the specimen is determined.

[0113] (3) Three-dimensional arithmetic roughness of the nonwoven fabric

[0114] Using a three-dimensional (3D) shape measuring machine (manufactured by Keyence Corporation, VR-3200), the three-dimensional arithmetic mean roughness (μm) of one side and the other side of each of 10 test pieces was measured by the evaluation method specified in International Standardization Organization (ISO) 25178 (2010). Then, the average value of the 20 measurement values obtained was calculated as the three-dimensional arithmetic mean roughness (μm) of the present invention. For the measurement of the three-dimensional arithmetic mean roughness (μm), at a magnification of 12 times (low magnification camera), the mode was set to the fine mode, and the filter processing settings were such that the filter category was set to "Gaussian", the S-filter was set to "none", the F-operation was set to "none", the L-filter was set to "none", and the correction of the end effect was set to "ON (open)".

[0115] (4) Single fiber strength of short fibers

[0116] The single fiber strength was measured in accordance with JIS L1015 (2010) 8.7.1. Specifically, in a state where a fiber was slowly elongated, both ends of the fiber were attached to paper using an adhesive to produce a specimen with the portion where the paper was attached as the clamping part. At this time, the area of the fiber between only the clamping parts was ensured to be 20 mm. The clamping parts of the specimen were installed in the clamp of a tensile tester (Orientec's Tensilon universal testing machine model RTG - 1210), and it was stretched at a clamp interval of 10 mm and a stretching speed of 10 mm / minute. The maximum load of the obtained elongation rate (mm) - load (N) curve was set as the single fiber strength (N). Ten specimens were measured for each, and their average value was calculated.

[0117] (5) Unit area weight of the water-absorbing polymer group

[0118] For specimens (10 cm × 10 cm) of the absorbent body that had been left standing in the standard state for 24 hours or more, water-absorbing polymers were collected from the water-absorbing polymer group of each specimen at 10 points. Then, the mass (g) of each in the standard state was weighed, and the mass per 1 m 2 was obtained (g / m 2 ), and the average value of the 10 points was calculated as the unit area weight (g / m 2 ) of the water-absorbing polymer group in the present invention.

[0119] (6) Saturated absorption amount of the water-absorbing polymer

[0120] The saturated absorption amount was measured in accordance with the tea bag method specified in JIS K7223 (1996). The test solution was physiological saline (0.90 mass% aqueous sodium chloride solution), and the immersion time was set to 24 hours. The tea bags (5 pieces) containing each specimen were measured, and the average value was calculated as the saturated absorption amount (g / g) of the water-absorbing polymer. In addition, the temperature of the physiological saline used and the measurement environment was 25 ± 2 °C.

[0121] (7) Gel liquid passing rate of the water-absorbing polymer

[0122] 0.05 g of a sample was immersed in 150 ml of physiological saline (0.90% sodium chloride aqueous solution) for 30 minutes to prepare hydrogel particles. Subsequently, the prepared hydrogel particles and the physiological saline solution were transferred to the bottom of a vertically erected cylinder (inner diameter: 25.4 mm, length: 56 cm, with scale marks at the 40 ml and 60 ml positions from the bottom). A metal mesh (106 μm mesh) and a freely openable stopcock were locked. A pressure shaft (58.5 g, 70 cm long) with a circular metal mesh (150 μm mesh) perpendicularly bonded to the metal surface was placed on the hydrogel particles, bringing the mesh into contact with the hydrogel particles. A weight (50.5 g) was then placed on the pressure shaft and allowed to stand for 1 minute. Next, the stopcock was opened and the time (T: seconds) required for the liquid level in the filtration cylinder to drop from the 60 ml mark to the 40 ml mark was measured. The gel flow rate (ml / min) in the present invention was calculated using the following formula. The temperature of the physiological saline solution used and the measurement environment was 25 ± 2°C.

[0123] Gel flow rate (ml / min) = 20ml x 60 / T seconds

[0124] (8) Particle size of water-absorbing polymer in the water-absorbing polymer group

[0125] A total of 5.00 g of water-absorbing polymer was collected from the water-absorbing polymer group. The collected 5.00 g of water-absorbing polymer was classified using trays 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 according to JIS Z8801. The classification was performed using an automatic oscillator (ASONE horizontal rotary sieve SKH-01) at a memory setting of 3 for 10 minutes. The mass of the water-absorbing polymer on each sieve and tray was measured, and the results were used to determine the particle size distribution of the water-absorbing polymer. In the overall particle size distribution of the water-absorbing polymer, the particle size corresponding to 50% by mass was defined as the particle size of the polymer in the water-absorbing polymer group of the present invention.

[0126] (9) Liquid diffusion area

[0127] Using a liquid permeability tester (manufactured by Lenzing Instruments, model: LISTER AC), the liquid diffusivity of the specimen was measured at 5 points. More specifically, at the specimen installation position of the tester, filter paper (manufactured by Nippon Paper Crecia, Kimtowel four - layer folded), a metal mesh (mesh size 1.5 mm), and a specimen (10 cm × 10 cm) were placed in sequence from the bottom. In addition, the surface of the specimen in contact with the metal mesh is the surface on the first non - woven fabric side in the first layer of the absorbent body of the present invention, the side where the second water - absorbing polymer is disposed when the absorbent body is formed in the second non - woven fabric, and the surface on the third non - woven fabric side in the second layer. Then, 5 ml of physiological saline (a substance obtained by coloring a 0.90 mass% sodium chloride aqueous solution with blue dye) was poured into the liquid inlet at the upper part of the tester, and the test was started. Then, 5 ml of physiological saline was dropped onto the surface of the specimen, and the end of the liquid passage was detected by the liquid - passage detection plate and the liquid - passage detection electrode of the tester. Next, within 5 seconds after the end of the liquid passage, a photograph was taken in such a way that the blue - dyed part of the specimen and the scale of the ruler were included in the same photograph. According to the scale of the ruler in the photograph, by relative comparison, the area (cm 2 ) of the blue - colored part was calculated. Then, the average value of the areas of 5 points of the specimen was calculated as the liquid diffusion area (cm 2 ) of the present invention. In addition, the temperature of the physiological saline and the measurement environment used was 25 ± 2°C.

[0128] (10) Density of the fibrous layer

[0129] Based on the value of the unit area weight of the fibrous layer / thickness of the fibrous layer, the mass per unit volume was calculated as the density of the fibrous layer (kg / m 3 ).

[0130] (11) Thickness of the fibrous layer

[0131] The fibrous layer was separated from the absorbent body, and based on the JIS L1913 (1998) 6.1.2A method, a thickness measuring device (a constant - pressure thickness measuring device manufactured by TECLOCK, model: PG11J) was used to measure the thickness of the separated fibrous - layer specimen. Each specimen piece (5 pieces) was measured, and the average value was calculated as the thickness (mm) of the fibrous layer. In addition, in the separation of the fibrous layer, in the case where the laminated interface is welded by an adhesive and cannot be separated by hand, while blowing cold spray onto the adhered laminated interface, it can be easily separated by pulling with hand.

[0132] (12) Particle size of the water - absorbing polymer contained in the fibrous layer

[0133] Collect 5.00 g of the water-absorbing polymer from the fibrous layer of the absorber. Next, use 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 according to JIS Z8801 to classify the 5.00 g of the collected water-absorbing polymer. In addition, the classification is carried out using an automatic shaker (horizontal rotary sieve SKH-01 manufactured by ASONE), shaking for 10 minutes at the memory setting value 3, measuring the mass of the water-absorbing polymer on each sieve and the tray, and using the results to obtain the particle size distribution of the water-absorbing polymer. Here, in the particle size distribution of the entire water-absorbing polymer, the particle diameter corresponding to 50% by mass is taken as the particle diameter of the water-absorbing polymer contained in the fibrous layer of the present invention.

[0134] (13) Content ratio of pulp fibers to water-absorbing polymer in the fibrous layer

[0135] Dig out an area of 5 cm × 5 cm in the thickness direction of the absorber to separate the fibrous layer, separate the pulp fibers and the water-absorbing polymer in the fibrous layer, find their respective weights, and divide the weight of the pulp fibers by the weight of the water-absorbing polymer to calculate the mass ratio of the pulp fibers to the water-absorbing polymer in the sample. Perform this for each sample piece (5 pieces) and calculate the average value as the content ratio of the pulp fibers to the water-absorbing polymer (mass of pulp fibers contained / mass of water-absorbing polymer contained).

[0136] (14) Absorber thickness

[0137] Based on the JIS L1913 (1998) 6.1.2A method, use a thickness measuring instrument (constant pressure thickness measuring instrument PG11J manufactured by TECLOCK) to measure the thickness of the sample. Perform the measurement for each sample piece (5 pieces) and calculate the average value as the thickness (mm) of the absorber.

[0138] (15) Absorbency of the absorber

[0139] Fix it to a stainless-steel inclined table with an inclination angle of 45° in the order of the backsheet and the absorbent body (specimen). In addition, the specimen is fixed in such a way that the longitudinal direction is consistent with the inclined direction, and the surface on the side of the third non-woven fabric is in contact with the backsheet, and it is fixed in an elongated state to eliminate wrinkles. Here, a porous polyethylene film is used for the backsheet. Then, at a position 1 cm downward from the upper end of the specimen, drip the physiological saline (a substance obtained by coloring a 0.90 mass% sodium chloride aqueous solution with a blue dye) prepared in a beaker from a microtube pump at a rate of 1.5 g / second, and continue to drip the physiological saline until it is observed that the physiological saline leaks out from the lower end face of the specimen. More specifically, prepare 500 g of physiological saline in the beaker, drip the physiological saline in the inclined state, and end the dripping at the time point when it is observed that the physiological saline leaks out from the lower end face of the specimen. Measure the weight (g) of the physiological saline remaining in the beaker without dripping, and calculate the absorption amount of the absorbent body by the following formula. In addition, the temperature of the physiological saline used and the measurement environment is 25 ± 2 °C.

[0140] Absorption amount of absorbent body (g) = 500 g - Q

[0141] Q (g): The amount of physiological saline remaining in the beaker without dripping

[0142] In addition, the higher the absorption amount shows, the more excellent the liquid leakage prevention property is.

[0143] (16) Absorption position of absorbent body

[0144] During the measurement of the absorption amount of the absorbent body in (15) above, it is observed that the physiological saline flows down along the inclined direction on the surface of the absorbent body and is absorbed inside the absorbent body and disappears at a certain position. Taking the dripping position as the starting point, taking the distance until the physiological saline disappears as the absorption position, and taking the maximum absorption position observed during the measurement of the absorption amount of the absorbent body in (15) (until the time point when it is observed that the physiological saline leaks out from the lower end face of the specimen) as the absorption position of the absorbent body.

[0145] (17) Comprehensive evaluation

[0146] Perform the comprehensive evaluation of the obtained absorbent body according to the following criteria.

[0147] A: The absorption amount is 300 g or more and the thickness is 7.0 mm or less.

[0148] B: The absorption amount is 250 g or more and the thickness is 7.0 mm or less.

[0149] C: Satisfy at least any one of the absorption amount less than 250 g and the thickness exceeding 7.0 mm.

[0150] [Example 1]

[0151] (Fiberous layer)

[0152] Commercially available water-absorbing polymers, SG-N21 (manufactured by SDP Global) and SA60SXII (manufactured by Sumitomo Seika Chemicals), were mixed at a ratio of 60:40 to prepare water-absorbing polymer A. Next, a fiber-opened pulp fiber web and water-absorbing polymer A were prepared at a mass ratio of 70:30 to give a total weight of 150 g / m 2 , and mix them uniformly in the air flow to obtain a fibrous layer with a thickness of 3.0 mm.

[0153] (First Nonwoven Fabric)

[0154] The staple fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) containing rayon were opened by a carding machine and then formed into a sheet with a weight of 20 g / m2 by a laying machine. 2 In addition, 70% by mass of the staple fibers containing rayon and 30% by mass of hollow staple fibers containing polyethylene terephthalate (fiber diameter: 30 μm, fiber length: 51 mm, single fiber strength: 0.30 N, hereinafter sometimes referred to as "short fibers A") were mixed using a carding machine, and after opening the fibers, a web laying machine was used to form a web with a unit area weight of 20 g / m 2 The obtained parallel net is overlapped with the cross net (cross net), and high-pressure water flow is applied from the cross net side to make them entangled with each other, and dried at 150°C for 3 minutes, thereby obtaining a unit area weight of 40g / m 2 The first nonwoven fabric a is a spunlace nonwoven fabric. The ratio of the staple fibers A contained in the first nonwoven fabric a is 15% by mass relative to the entire first nonwoven fabric a. Furthermore, the ratio of the staple fibers including rayon contained in the first nonwoven fabric a is 85% by mass relative to the entire first nonwoven fabric a.

[0155] (Second non-woven fabric)

[0156] The staple fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) containing rayon were opened by a carding machine and then formed into a sheet with a weight of 15 g / m2 by a laying machine. 2 Parallel mesh and unit area weight 15g / m 2 The obtained parallel web and cross web are overlapped, high pressure water flow is applied to make them entangled with each other, and dried at 150°C for 3 minutes, thereby obtaining a unit area weight of 30g / m 2 The second nonwoven fabric a of the spunlace nonwoven fabric.

[0157] (Third non-woven fabric)

[0158] Use the same non-woven fabric as the second non-woven fabric.

[0159] (Absorbent body)

[0160] Take the parallel net side of the first non-woven fabric as the first side, and spray styrene-based hot melt adhesive on the first side to make it 2 g / m 2 , and evenly disperse the first water-absorbing polymer (NS300 manufactured by SDP Global) thereon to make the unit area weight 100 g / m 2 . Then, cover one side of the second non-woven fabric thereon and press-bond. Then, spray styrene-based hot melt adhesive on one side of the third non-woven fabric to make it 2 g / m 2 , and evenly disperse the second water-absorbing polymer (SA60S manufactured by Sumitomo Seika) thereon to make the unit area weight 150 g / m 2 . Then, cover and press-bond in such a way that the other side of the second non-woven fabric (the side opposite to the first water-absorbing polymer dispersion side) contacts the second water-absorbing polymer dispersed on the third non-woven fabric. Here, the first water-absorbing polymer group is directly or indirectly fixed to the first non-woven fabric. In addition, the second water-absorbing polymer group is directly or indirectly fixed to the third non-woven fabric. Then, spray styrene-based hot melt adhesive on the side on the first non-woven fabric side (the side opposite to the first water-absorbing polymer dispersion side) to make it 2 g / m 2 , cover the fibrous layer thereon and fix it. By cutting the obtained object into a rectangular shape with a long side of 20 cm × a short side of 10 cm, an absorbent body in a rectangular shape is obtained. The structure and performance of the absorbent body are shown in Table 1.

[0161] [Examples 2 to 4]

[0162] An absorbent body is obtained in the same manner as in Example 1 except for changing the thickness of the fibrous layer. The structures and performances of these absorbent bodies are shown in Table 1 (Examples 2 to 3) and Table 2 (Example 4).

[0163] [Example 5]

[0164] An absorbent body is obtained in the same manner as in Example 1 except for changing the mass ratio of the fibrillated pulp fiber web of the fibrous layer to the water-absorbing polymer A to 50:50. The structure and performance of the absorbent body are shown in Table 2.

[0165] [Example 6]

[0166] An absorbent body is obtained in the same manner as in Example 1 except for changing the mass ratio of the fibrillated pulp fiber web of the fibrous layer to the water-absorbing polymer A to 85:15. The structure and performance of the absorbent body are shown in Table 2.

[0167] [Example 7]

[0168] An absorbent body was obtained in the same manner as in Example 1, except that the water-absorbing polymer contained in the fibrous layer was changed to a substance obtained by classifying the water-absorbing polymer A using sieves with a nominal mesh size of 212 μm and 300 μm according to JIS Z8801. The structure and properties of the absorbent body are shown in Table 3.

[0169] [Example 8]

[0170] An absorbent body was obtained in the same manner as in Example 1, except that the water-absorbing polymer contained in the fibrous layer was changed to a substance obtained by classifying the water-absorbing polymer A using sieves with a nominal mesh size of 850 μm and 1 mm according to JIS Z8801. The structure and properties of the absorbent body are shown in Table 3.

[0171] [Example 9]

[0172] (First non-woven fabric)

[0173] The short fibers containing rayon (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) were opened by a carding machine and then formed into a parallel web with a basis weight of 10 g / m 2 by a cross-laying machine. In addition, 40% by mass of the short fibers containing rayon and 60% by mass of the short fibers containing short fiber A were mixed by a carding machine, opened, and then formed into a cross web with a basis weight of 10 g / m 2 by a cross-laying machine. The obtained parallel web and cross web were overlapped (cross-cross web), and high-pressure water was applied from the cross-web side to entangle them with each other, and then dried at 150 °C for 3 minutes to obtain a first non-woven fabric b which is a spunlace non-woven fabric with a basis weight of 20 g / m 2 . In addition, the proportion of short fiber A contained in the first non-woven fabric b is 30% by mass based on the whole of the first non-woven fabric b. In addition, the proportion of the short fibers containing rayon contained in the first non-woven fabric b is 70% by mass based on the whole of the first non-woven fabric b.

[0174] (Absorbent body) An absorbent body was obtained in the same manner as in Example 1, except that the first non-woven fabric was changed to the first non-woven fabric b and the basis weight of the first water-absorbing polymer was changed to 125 g / m 2 . The structure and properties of the absorbent body are shown in Table 3.

[0175] [Example 10]

[0176] (First non-woven fabric)

[0177] The short fibers containing rayon staple fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) were opened by a carding machine and then formed into a parallel web with a basis weight of 25 g / m² by a cross-lapper. 2 In addition, 80% by mass of the short fibers containing rayon and 20% by mass of the short fibers containing short fiber A were mixed by a carding machine, opened, and then formed into a cross-web with a basis weight of 25 g / m² by a cross-lapper. 2 The obtained parallel web and cross-web were overlapped (cross-cross web), and high-pressure water was applied from the cross-web side to entangle them with each other, and then dried at 150 °C for 3 minutes, thereby obtaining a first nonwoven fabric c of spunlace nonwoven fabric with a basis weight of 50 g / m². 2 In addition, the proportion of short fiber A contained in the first nonwoven fabric c was 10% by mass based on the whole of the first nonwoven fabric c. In addition, the proportion of the short fibers containing rayon contained in the first nonwoven fabric c was 90% by mass based on the whole of the first nonwoven fabric c.

[0178] (Second nonwoven fabric)

[0179] The short fibers containing rayon staple fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) were opened by a carding machine and then formed into a parallel web with a basis weight of 22.5 g / m² and a cross-web with a basis weight of 22.5 g / m² by a cross-lapper. 2 The obtained parallel web and cross-web were overlapped, and high-pressure water was applied to entangle them with each other, and then dried at 150 °C for 3 minutes, thereby obtaining a second nonwoven fabric c of spunlace nonwoven fabric with a basis weight of 45 g / m². 2 2

[0180] (Absorbent)

[0181] Except that the first nonwoven fabric was changed to the first nonwoven fabric c, the second nonwoven fabric was changed to the second nonwoven fabric c, and the basis weight of the first water-absorbing polymer was changed to 75 g / m², 2 an absorbent was obtained in the same manner as in Example 1. The structure and properties of the absorbent are shown in Table 4.

[0182] [Example 11]

[0183] (Third nonwoven fabric)

[0184] The short fibers containing rayon staple fibers (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) were opened by a carding machine and then formed into a parallel web with a basis weight of 25 g / m² and a cross-web with a basis weight of 25 g / m² by a cross-lapper. 2 2Cross web. The obtained parallel web and cross web are overlapped, and high-pressure water flow is applied to make them wind around each other, and dried at 150 °C for 3 minutes, thereby obtaining the third non-woven fabric d of the spunlace non-woven fabric with a basis weight of 50 g / m². 2

[0185] (Absorbent body)

[0186] Except that the third non-woven fabric is changed to the third non-woven fabric d, the second water-absorbing polymer is changed to NS300 manufactured globally by SDP, and the basis weight of the second water-absorbing polymer is changed to 125 g / m², 2 an absorbent body is obtained in the same manner as in Example 1. The structure and properties of the absorbent body are shown in Table 4.

[0187] [Example 12]

[0188] (Third non-woven fabric)

[0189] 70% by mass of short fibers containing rayon (fiber diameter: 13 μm, fiber length: 51 mm, single fiber strength: 0.04 N) and 30% by mass of short fibers containing short fiber A are mixed by a carding machine. After fiber opening, a parallel web with a basis weight of 10 g / m² 2 and a cross web with a basis weight of 10 g / m² 2 are obtained. The obtained parallel web and cross web are overlapped, and high-pressure water flow is applied to make them wind around each other, and dried at 150 °C for 3 minutes, thereby obtaining the third non-woven fabric e of the spunlace non-woven fabric with a basis weight of 20 g / m². 2

[0190] (Absorbent body)

[0191] Except that the third non-woven fabric is changed to the third non-woven fabric e and the basis weight of the second water-absorbing polymer is changed to 175 g / m², 2 an absorbent body is obtained in the same manner as in Example 1. The structure and properties of the absorbent body are shown in Table 4.

[0192] [Example 13]

[0193] Except that the proportion of short fibers containing rayon in the first non-woven fabric is changed to 100% by mass with respect to the whole of the first non-woven fabric, that is, except that the first non-woven fabric is changed to a non-woven fabric not containing short fiber A, an absorbent body is obtained in the same manner as in Example 1. The structure and properties of the absorbent body are shown in Table 5.

[0194] [Example 14]

[0195] An absorber was obtained in the same manner as in Example 1, except that the proportion of the short fiber A contained in the first nonwoven fabric was changed to 50% by mass based on the whole of the first nonwoven fabric, and the proportion of the short fiber containing rayon contained in the first nonwoven fabric was changed to 50% by mass based on the whole of the first nonwoven fabric. The structure and properties of the absorber are shown in Table 5.

[0196] [Example 15]

[0197] An absorber was obtained in the same manner as in Example 1, except that the weight per unit area of the first water-absorbent polymer was changed to 25 g / m 2 . The structure and properties of the absorber are shown in Table 5.

[0198] [Example 16]

[0199] An absorber was obtained in the same manner as in Example 1, except that the short fibers in the second nonwoven fabric were changed to 6,0% by mass of the short fibers containing rayon and 40% by mass of the short fibers containing polyethylene terephthalate (fiber diameter: 15 μm, fiber length: 51 mm). The structure and properties of the absorber are shown in Table 6.

[0200] [Example 17]

[0201] An absorber was obtained in the same manner as in Example 1, except that the weight per unit area of the second nonwoven fabric was changed to 15 g / m 2 . The structure and properties of the absorber are shown in Table 6.

[0202] [Example 18]

[0203] An absorber was obtained in the same manner as in Example 1, except that the weight per unit area of the second nonwoven fabric was changed to 60 g / m 2 . The structure and properties of the absorber are shown in Table 6.

[0204] [Comparative Example 1]

[0205] An absorber was obtained in the same manner as in Example 1, except that the second nonwoven fabric and the second layer (the second water-absorbent polymer group and the third nonwoven fabric) were not used, the weight per unit area of the first water-absorbent polymer was set to 250 g / m 2 , and the arrangement of the fibrous layer was changed to the lower part of the surface of the first water-absorbent polymer group that became the first layer (the surface opposite to the surface of the first nonwoven fabric). The structure and properties of the absorber are shown in Table 7.

[0206] [Comparative Example 2]

[0207] An absorber was obtained in the same manner as in Example 1, except that the second nonwoven fabric and the second layer (the second water-absorbent polymer group and the third nonwoven fabric) were not used, and the weight per unit area of the first water-absorbent polymer was set to 250 g / m2 , except for changing the arrangement of the fibrous layer to the lower part of the surface of the first nonwoven fabric that becomes the first layer (the surface opposite to the surface of the first water-absorbent polymer group), an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 7.

[0208] [Comparative Example 3]

[0209] Except that the basis weight of the fibrous layer was set to 400 g / m 2 , the thickness of the fibrous layer was set to 8.0 mm, and the structure of the absorber was changed to only the fibrous layer, an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 7.

[0210] [Comparative Example 4]

[0211] Except that the thickness of the fibrous layer was changed to 6.0 mm, an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 8.

[0212] [Comparative Example 5]

[0213] Except that, as the water-absorbent polymer contained in the fibrous layer, a material obtained by classifying water-absorbent polymer A using sieves with nominal mesh sizes of 75 μm and 106 μm according to JIS Z8801 was used, an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 8.

[0214] [Comparative Example 6]

[0215] Except that, as the water-absorbent polymer contained in the fibrous layer, a material obtained by classifying water-absorbent polymer A using sieves with nominal mesh sizes of 1 mm and 1.4 mm according to JIS Z8801 was used, an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 8.

[0216] [Comparative Example 7]

[0217] Except that the mass ratio of the fibrillated pulp fiber web of the fibrous layer to water-absorbent polymer A was changed to 35:65, an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 9.

[0218] [Comparative Example 8]

[0219] Except that the mass ratio of the fibrillated pulp fiber web of the fibrous layer to water-absorbent polymer A was changed to 90:10, an absorber was obtained in the same manner as in Example 1. The structure and properties of the absorber are shown in Table 9.

[0220] [Comparative Example 9]

[0221] An absorbent body was obtained in the same manner as in Example 1, except that the second non-woven fabric was changed to a spunbond non-woven fabric (made of polypropylene, basis weight 10 g / m 2 ). The structure and properties of the absorbent body are shown in Table 9.

[0222] [Comparative Example 10]

[0223] An absorbent body was obtained in the same manner as in Example 1, except that the first non-woven fabric was changed to a spunbond non-woven fabric (made of polypropylene, basis weight 10 g / m 2 ). The structure and properties of the absorbent body are shown in Table 10.

[0224] [Comparative Example 11]

[0225] (First non-woven fabric)

[0226] A first non-woven fabric ca was obtained by calendering the first non-woven fabric c (cylinder pressure: 4 kgf / cm 2 , roll temperature: 20 °C, speed: 1 m / min).

[0227] (Absorbent body)

[0228] An absorbent body was obtained in the same manner as in Example 1, except that the first non-woven fabric was changed to the first non-woven fabric ca. The structure and properties of the absorbent body are shown in Table 10.

[0229] [Comparative Example 12]

[0230] An absorbent body was obtained in the same manner as in Example 1, except that the third non-woven fabric was changed to a spunbond non-woven fabric (made of polypropylene, basis weight 10 g / m 2 ). The structure and properties of the absorbent body are shown in Table 10. [Comparative Example 13]

[0231] An absorbent body was obtained in the same manner as in Example 1, except that the fibrous layer was not used. The structure and properties of the absorbent body are shown in Table 11.

[0232] [Example 19]

[0233] An absorbent body was obtained in the same manner as in Example 1, except that the amount of hot melt adhesive applied to the first non-woven fabric and the third non-woven fabric was changed to 4 g / m 2 respectively. The structure and properties of the absorbent body are shown in Table 11.

[0234] [Example 20]

[0235] An absorbent body was obtained in the same manner as in Example 1, except that the amount of hot melt adhesive applied to the first non-woven fabric and the third non-woven fabric was changed to 10 g / m 2 respectively. The structure and properties of the absorbent body are shown in Table 11.

[0236] [Table 1]

[0237] [Table 1]

[0238]

[0239] 1) Value obtained by dividing the mass content of the pulp fibers in the fibrous layer by the mass content of the water-absorbing polymer

[0240] 2) The proportion of short fibers A having a single fiber strength of 0.15 N or more relative to the entire first nonwoven fabric

[0241] 3) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer

[0242] 4) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer

[0243] [Table 2]

[0244] [Table 2]

[0245]

[0246] 1) Value obtained by dividing the mass content of the pulp fibers in the fibrous layer by the mass content of the water-absorbing polymer

[0247] 2) The proportion of short fibers A having a single fiber strength of 0.15 N or more relative to the entire first nonwoven fabric

[0248] 3) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer

[0249] 4) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer

[0250] [Table 3]

[0251] [Table 3]

[0252]

[0253] 1) Value obtained by dividing the mass content of the pulp fibers in the fibrous layer by the mass content of the water-absorbing polymer

[0254] 2) The proportion of short fibers A having a single fiber strength of 0.15 N or more relative to the entire first nonwoven fabric

[0255] 3) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer

[0256] 4) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer

[0257] [Table 4]

[0258] [Table 4]

[0259]

[0260] 1) The value obtained by dividing the contained mass of pulp fibers in the fibrous layer by the contained mass of the water-absorbing polymer

[0261] 2) The proportion of short fiber A with a single fiber strength of 0.15 N or more relative to the entire first non-woven fabric

[0262] 3) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer

[0263] 4) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer

[0264] [Table 5]

[0265] [Table 5]

[0266]

[0267] 1) The value obtained by dividing the contained mass of pulp fibers in the fibrous layer by the contained mass of the water-absorbing polymer

[0268] 2) The proportion of short fiber A with a single fiber strength of 0.15 N or more relative to the entire first non-woven fabric

[0269] 3) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer

[0270] 4) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer

[0271] [Table 6]

[0272] [Table 6]

[0273]

[0274] 1) The value obtained by dividing the contained mass of pulp fibers in the fibrous layer by the contained mass of the water-absorbing polymer

[0275] 2) The proportion of short fiber A with a single fiber strength of 0.15 N or more relative to the entire first non-woven fabric

[0276] 3) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer

[0277] 4) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer

[0278] [Table 7]

[0279] [Table 7]

[0280]

[0281] 1) Value obtained by dividing the mass content of the pulp fibers in the fibrous layer by the mass content of the water-absorbing polymer

[0282] 2) The proportion of short fibers A having a single fiber strength of 0.15 N or more relative to the entire first nonwoven fabric

[0283] 3) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer

[0284] 4) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer

[0285] [Table 8]

[0286] [Table 8]

[0287]

[0288] 1) Value obtained by dividing the mass content of the pulp fibers in the fibrous layer by the mass content of the water-absorbing polymer

[0289] 2) The proportion of short fibers A having a single fiber strength of 0.15 N or more relative to the entire first nonwoven fabric

[0290] 3) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer

[0291] 4) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer

[0292] [Table 9]

[0293] [Table 9]

[0294]

[0295] 1) Value obtained by dividing the mass content of the pulp fibers in the fibrous layer by the mass content of the water-absorbing polymer

[0296] 2) The proportion of short fibers A having a single fiber strength of 0.15 N or more relative to the entire first nonwoven fabric

[0297] 3) The value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer

[0298] 4) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer

[0299] [Table 10]

[0300] [Table 10]

[0301]

[0302] 1) The value obtained by dividing the contained mass of pulp fibers in the fibrous layer by the contained mass of the water-absorbing polymer

[0303] 2) The proportion of short fiber A having a single fiber strength of 0.15 N or more with respect to the entire first non-woven fabric

[0304] 3) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer

[0305] 4) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer

[0306] [Table 11]

[0307] [Table 11]

[0308]

[0309] 1) The value obtained by dividing the contained mass of pulp fibers in the fibrous layer by the contained mass of the water-absorbing polymer

[0310] 2) The proportion of short fiber A having a single fiber strength of 0.15 N or more with respect to the entire first non-woven fabric

[0311] 3) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the first layer

[0312] 4) The value obtained by dividing the liquid diffusion area of the second non-woven fabric by the liquid diffusion area of the second layer

[0313] Here, the absorbers of Examples 1 to 20 are compared with the absorbers of Comparative Examples 1 to 3. The absorbers of Examples 1 to 20 are absorbers composed of a fibrous layer, a first layer, a second non-woven fabric, and a second layer in this order. In contrast, the absorber of Comparative Example 1 is an absorber composed of a first layer and a fibrous layer in this order, the absorber of Comparative Example 2 is an absorber composed of a fibrous layer and a first layer in this order, and the absorber of Comparative Example 3 is an absorber containing only a fibrous layer. Thus, it can be said that the absorption characteristics of the absorbers of Examples 1 to 20 are superior to those of Comparative Examples 1 to 2, the thickness of the absorber is thinner than that of the absorber of Comparative Example 3, and the wearing feeling is excellent when applied to sanitary material products.

[0314] The absorbent bodies of Examples 1 to 20 were compared with the absorbent body of Comparative Example 4. Focusing on the density and thickness of the fibrous layer, the absorbent body of Comparative Example 4 had a very low density and a very large thickness of the fibrous layer. In contrast, the absorbent bodies of Examples 1 to 20 had a moderately high density and a moderately thin thickness of the fibrous layer. Therefore, the absorbent bodies of Examples 1 to 20 had superior absorption properties to those of Comparative Example 4.

[0315] The absorbent bodies of Examples 1 to 20 were compared with the absorbent bodies of Comparative Examples 5 and 6. Focusing on the particle size of the water-absorbing polymer contained in the fibrous layer, the absorbent body of Comparative Example 5 had a very small particle size of the water-absorbing polymer contained in the fibrous layer, while the absorbent body of Comparative Example 6 had a very large particle size of the water-absorbing polymer contained in the fibrous layer. In comparison, the absorbent bodies of Examples 1 to 20 had a moderate particle size of the water-absorbing polymer contained in the fibrous layer. Therefore, the absorbent bodies of Examples 1 to 20 had superior absorption properties to those of Comparative Examples 5 and 6.

[0316] The absorbent bodies of Examples 1-20 were compared with the absorbent bodies of Comparative Examples 7-8. Focusing on the ratio of pulp fiber to water-absorbent polymer content in the fibrous layer, the absorbent body of Comparative Example 7 had a very low ratio of pulp fiber to water-absorbent polymer content in the fibrous layer, while the absorbent body of Comparative Example 8 had a very high ratio of pulp fiber to water-absorbent polymer content in the fibrous layer. In comparison, the absorbent bodies of Examples 1-20 had a moderate ratio of pulp fiber to water-absorbent polymer content in the fibrous layer. Therefore, the absorbent bodies of Examples 1-20 exhibit superior absorption properties compared to those of Comparative Examples 7-8.

[0317] The absorbent bodies of Examples 1 to 20 were compared with the absorbent body of Comparative Example 9. The absorbent bodies of Examples 1 to 20 had a second nonwoven fabric composed solely of hydrophilic fibers, whereas the absorbent body of Comparative Example 9 had a second nonwoven fabric composed solely of hydrophobic fibers. Furthermore, considering the values obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer, and the values obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer, the absorbent body of Comparative Example 9 had a second nonwoven fabric with poorer liquid diffusion properties than the first and second layers. In contrast, the absorbent bodies of Examples 1 to 20 had a second nonwoven fabric with better liquid diffusion properties than the first and second layers. Therefore, the absorption characteristics of the absorbent bodies of Examples 1 to 20 were superior to those of Comparative Example 9.

[0318] The absorbents of Examples 1 to 20 were compared with the absorbent of Comparative Example 10. Focusing on the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer, the absorbent of Comparative Example 10 was an absorbent in which the liquid diffusion area of the first layer was very small relative to the liquid diffusion area of the second nonwoven fabric. In contrast, the absorbents of Examples 1 to 20 were absorbents in which the liquid diffusion area of the first layer was moderately small relative to the liquid diffusion area of the second nonwoven fabric. Thus, the absorbent characteristics of the absorbents of Examples 1 to 20 were superior to those of the absorbent of Comparative Example 10.

[0319] The absorbents of Examples 1 to 20 were compared with the absorbent of Comparative Example 11. Focusing on the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer, the absorbent of Comparative Example 11 was an absorbent in which the liquid diffusion area of the second nonwoven fabric was inferior to that of the first layer. In contrast, the absorbents of Examples 1 to 20 were absorbents in which the liquid diffusion area of the second nonwoven fabric was superior to that of the first layer. Thus, the absorbent characteristics of the absorbents of Examples 1 to 20 were superior to those of the absorbent of Comparative Example 11.

[0320] The absorbents of Examples 1 to 20 were compared with the absorbent of Comparative Example 12. Focusing on the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer, the absorbent of Comparative Example 12 was an absorbent in which the liquid diffusion area of the second layer was very small relative to the liquid diffusion area of the second nonwoven fabric. In contrast, the absorbents of Examples 1 to 20 were absorbents in which the liquid diffusion area of the second layer was moderately small relative to the liquid diffusion area of the second nonwoven fabric. Thus, the absorbent characteristics of the absorbents of Examples 1 to 20 were superior to those of the absorbent of Comparative Example 12.

[0321] The absorbent of Example 1 was compared with the absorbent of Example 3. The density of the fibrous layer included in the absorbent of Example 1 was moderately larger than the density of the fibrous layer included in the absorbent of Example 3. The absorbent of Example 1 could further suppress liquid leakage from the fibrous layer. Thus, the absorbent characteristics of the absorbent of Example 1 were superior to those of the absorbent of Example 3.

[0322] The absorbent of Example 1 was compared with the absorbent of Example 6. The ratio of the content of pulp fibers to the water-absorbing polymer in the fibrous layer included in the absorbent of Example 1 was moderately smaller than the ratio of the content of pulp fibers to the water-absorbing polymer in the fibrous layer included in the absorbent of Example 6. The absorbent of Example 1 could further suppress liquid leakage from the fibrous layer. Thus, the absorbent characteristics of the absorbent of Example 1 were superior to those of the absorbent of Example 6.

[0323] The absorber of Example 1 was compared with the absorber of Example 7. In terms of the particle size of the water-absorbing polymer in the fibrous layer included in the absorber of Example 7, the particle size of the water-absorbing polymer in the fibrous layer included in the absorber of Example 1 was moderately large, and the absorber of Example 1 could further suppress liquid leakage from the fibrous layer. Thus, the absorption characteristics of the absorber of Example 1 were superior to those of the absorber of Example 7.

[0324] The absorbers of Examples 1 to 20 were compared with the absorber of Comparative Example 13. Focusing on the absorption amount of the absorber, the absorber of Comparative Example 13 was an absorber with a small absorption amount, while the absorbers of Examples 1 to 20 were absorbers with a large absorption amount. Thus, the absorption characteristics of the absorbers of Examples 1 to 20 were superior to those of the absorber of Comparative Example 13.

[0325] In addition, the absorber of Example 1 was compared with the absorbers of Example 19 and Example 20. Regarding the spreading amount of the adhesive for each of the first layer and the second layer, the absorber of Example 1 was moderately smaller than the absorbers of Example 19 and Example 20. The liquid diffusion area of the first layer included in the absorber of Example 1 was moderately larger than the liquid diffusion area of the first layer included in the absorbers of Example 19 and Example 20, and the absorber of Example 1 could increase the absorption amount of urine or the like by the water-absorbing polymer or the first nonwoven fabric itself in the first layer. In addition, regarding the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer, the absorber of Example 1 was moderately smaller than the absorbers of Example 19 and Example 20. In addition, regarding the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer, the absorber of Example 1 was moderately smaller than the absorbers of Example 19 and Example 20. Thus, compared with the absorbers of Example 19 and Example 20, the transfer of urine or other liquids from the fibrous layer to the first layer in the absorber of Example 1 became smooth, and the absorption characteristics of the absorber of Example 1 were superior to those of the absorbers of Example 19 and Example 20.

[0326] Industrial Applicability

[0327] The absorber of the present invention is an absorber with excellent absorption characteristics and can be suitably used as various sanitary material products such as tape-type disposable diapers, panties-type disposable diapers, sanitary napkins, and urine-absorbing pads.

Claims

1. An absorber, sequentially comprising a fibrous layer, a first nonwoven fabric, a first water-absorbent polymer group, a second nonwoven fabric, a second water-absorbent polymer group, and a third nonwoven fabric, and having a thickness of 7.0 mm or less. In the absorber, The density of the fibrous layer is 30 kg / m 3 ~100 kg / m 3 , and the thickness is 5.0 mm or less. the fibrous layer contains pulp fibers and a water-absorbent polymer, the particle size of the water-absorbent polymer is 200 μm to 1000 μm, the content ratio of the pulp fibers to the water-absorbent polymer (the mass of the pulp fibers contained / the mass of the water-absorbent polymer contained) is 1.0 to 6.0, the first nonwoven fabric and the first water-absorbent polymer group form a first layer, the third nonwoven fabric and the second water-absorbent polymer group form a second layer, the first water-absorbent polymer group is directly or indirectly fixed to the first nonwoven fabric, the second water-absorbent polymer group is directly or indirectly fixed to the third nonwoven fabric, the second nonwoven fabric contains 60% by mass or more of hydrophilic fibers with respect to the whole of the second nonwoven fabric, The liquid diffusion area of the first layer is 40 cm 2 ~90 cm 2 , the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the first layer is 1.1 to 2.0, the value obtained by dividing the liquid diffusion area of the second nonwoven fabric by the liquid diffusion area of the second layer is 1.1 to 2.

5.

2. The absorber according to claim 1, wherein The hydrophilic fiber is a rayon fiber.

3. The absorber according to claim 1 or 2, wherein, The unit area weight of the second non-woven fabric is 20 g / m 2 ~50 g / m 2 .

4. The absorber according to any one of claims 1 to 3, wherein, The first nonwoven fabric contains short fiber A having a single fiber strength of 0.15 N or more, the content of the short fiber A is 5% by mass to 40% by mass with respect to the whole of the first nonwoven fabric.

5. The absorber according to any one of claims 1 to 4, wherein, The unit area weight of the first water-absorbing polymer group is 50 g / m 2 ~400 g / m 2 .

6. The absorber according to any one of claims 1 to 5, wherein The saturation absorption amount of the water-absorbent polymer contained in the second water-absorbent polymer group is 25 g / g to 70 g / g.

7. A sanitary material product, comprising the absorber according to any one of claims 1 to 6.

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