JP2015123195A - Absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbent article, when viewing an absorber from a surface sheet side, having a small area where liquid is spread laterally and having excellent liquid diffusivity in a lower layer of the absorber.SOLUTION: The absorbent article includes a top sheet 20, a backside sheet 21, and absorbers 10 and 10A disposed between both sheets. The absorbers 10 and 10A consist of a laminate structure formed by superposing two or more layers. A first layer 11 consisting of a resin bond non-woven fabric is disposed at a position closest to the top sheet 20. A second layer 12 consisting of a composite water absorptive polymer 14 formed by embedding a fiber material at least in a part of the absorptive polymer surface, is disposed between the backside sheet 21 and the first layer 11.

Description

  The present invention relates to absorbent articles such as disposable diapers and sanitary napkins.

  Various water-absorbing composites in which water-absorbing polymers and fibers are combined are known. For example, Patent Document 1 describes a water-absorbing composite composed of a water-absorbing polymer and hydrophilic fibers in which at least a part of the fiber length is embedded in the polymer. Patent Document 2 describes a water-insoluble water-absorbent resin, a water-absorbent composite material composed of fibers in which at least a part of the fiber length is embedded in the water-insoluble water-absorbent resin, and an absorbent article composed of cellulosic fibers. Has been.

  Apart from the above technique, a sheet material obtained by mixing a water-absorbing polymer with fibers is known. For example, Patent Document 3 includes a first layer of a sheet-like support, a second layer of a highly water-absorbent resin, and a third layer of a covering bonding agent mainly composed of microfibrillar ultrafine fibers. A super absorbent sheet is described. In Patent Document 4, a thermoplastic resin is coated on a sheet material of a water-permeable thermoplastic dry nonwoven fabric that has been subjected to a hydrophilic treatment, and a highly water-absorbing polymer is disposed on the thermoplastic resin. An absorbent sheet is described in which a polymer is fixed and held by the thermoplastic resin. Patent Document 5 describes a nanofiber assembly made of a thermoplastic polymer and an absorbent article made of a highly water-absorbent resin whose water absorption is 50 to 80 times the mass of the nanofiber assembly. Patent Document 6 describes a method of forming a nonwoven web used as a constituent member of absorbent articles such as disposable diapers and sanitary napkins. In this method, (a) a step of forming nanofibers from a melt film fibrillation process, (b) a step of forming a fluid flow containing fine particles of a liquid-absorbing gel material, and (c) the nanofibers as the fine particles. Mixing to form a nanofiber-particulate mixture, and (d) depositing the mixture on a surface to form a web.

JP 63-63723 A Japanese Unexamined Patent Publication No. 63-73958 JP-A-11-170414 JP 2001-046435 A JP 2006-057200 A Special table 2007-528944

  In the techniques described in Patent Documents 1 and 2, a water-absorbing composite material in which a water-absorbing polymer and a fiber are combined is used as it is, or mixed with hydrophilic fibers such as pulp. That is, the water-absorbing composite material is not used as a material constituting one layer of the absorber having a multilayer structure.

  In the techniques described in Patent Documents 3 to 6, since the water-absorbing polymer is not complexed with the fiber, an unpleasant granular feeling expressed by the polymer may be given to the user. Further, although the water-absorbing polymer is less likely to fall off, the polymer is not completely restrained, and thus gel blocking may occur due to swelling caused by water absorption.

  Therefore, the subject of this invention is providing the absorbent article which can eliminate the fault which the prior art mentioned above has.

The present invention relates to an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable or liquid-permeable back sheet, and a liquid-retaining absorbent disposed between both sheets.
The absorber has a laminated structure in which two or more layers are laminated,
A first layer made of a resin bonded nonwoven fabric is disposed at a position closest to the surface sheet;
Absorbent article in which a second layer made of a composite water-absorbing polymer, in which a fiber material is embedded, is disposed on at least a part of the surface of the water-absorbing polymer between the back sheet and the first layer. Is to provide.

  ADVANTAGE OF THE INVENTION According to this invention, when the absorber is seen from the surface sheet side, the spread area of the liquid to the horizontal direction is small, and the absorbent article excellent in the diffusibility of the liquid in the lower layer of an absorber is provided. Moreover, according to this invention, the water absorption speed | rate is quick and the absorbent article by which the gel blocking of the water absorbing polymer was suppressed is provided.

Drawing 1 is a mimetic diagram showing the structure of the longitudinal section of the absorber in the absorptive article of the present invention. 2 (a) and 2 (b) are schematic views showing states of liquid permeation and diffusion in the absorber shown in FIG. Drawing 3 is a mimetic diagram showing the structure of the longitudinal section of another absorber in the absorptive article of the present invention. FIG. 4 is a schematic view showing an apparatus for producing an ultrafine fiber nonwoven fabric by a melt blown method.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The absorbent article of the present invention includes a top sheet, a back sheet, and an absorbent body disposed between both sheets. The top sheet is liquid-permeable, and is disposed at a position facing the wearer's body when the absorbent article is worn. The back sheet is liquid-impermeable or hardly permeable, and is disposed on the side far from the wearer's body when the absorbent article is worn. In addition to these members, the absorbent article may include members for improving various performances of the article, depending on the specific application. For example, on the skin facing surface of the absorbent article, a pair of leak-proof cuffs extending in the longitudinal direction of the article may be provided at positions on both sides in the width direction of the article. Each leak-proof cuff has a fixed end and a free end extending in the longitudinal direction of the absorbent article, and can be fixed to the skin facing surface of the absorbent article at the position of the fixed end. An elastic member such as rubber thread may be fixed to the free end in an extended state along the extending direction.

  The absorber has a laminated structure in which two or more layers are laminated. Each layer other than the second layer composed of the composite water-absorbing polymer constituting the absorbent body may be composed of a material having shape retaining property such as a sheet, or a powder having a predetermined thickness. It may be a layer formed by spraying so as to have no shape retention. Each layer constituting the absorber is distinguished from other layers by being composed of different materials. Moreover, each layer which comprises an absorber may be joined by the predetermined joining means, and the opposing surface with an adjacent layer may be joined. Further, of the layers constituting the absorber, the layer closest to the topsheet may be bonded to the surface facing the topsheet or may not be bonded. Similarly, among the layers constituting the absorber, the layer closest to the back sheet may or may not be bonded to the surface facing the back sheet. Examples of the bonding means between the layers and the bonding means between the layer and the top sheet or the back sheet include adhesion by an adhesive, thermal fusion, and ultrasonic bonding. These joining means can be appropriately selected depending on the type of material constituting the layer and the specific application of the absorbent article.

  In the absorbent body composed of a multi-layer structure, the periphery of the multi-layer structure may or may not be covered with a liquid-permeable sheet, but is preferably not covered. . By not being coated, it is possible to suppress a decrease in the diffusion and absorption rate of the liquid immediately after the liquid has permeated the top sheet. In addition, the cost can be reduced. As the liquid-permeable sheet, for example, a hydrophilic thin paper containing pulp, a nonwoven fabric made of hydrophilic thermoplastic fibers, or the like can be used.

  In FIG. 1, the state of the cross section along the thickness direction of the absorber 10 in the absorbent article of this invention is typically shown. In the figure, the upper side is the skin facing surface side, and the lower side is the non-skin facing surface side. The absorber 10 is disposed between the top sheet 20 and the back sheet 21. The absorber 10 in this embodiment has a two-layer structure. In detail, the absorber 10 has the 1st layer 11 distribute | arranged to the position nearest to the surface sheet 20. FIG. Moreover, the absorber 10 has the 2nd layer 12 distribute | arranged between the back surface sheet 21 and the 1st layer 11. FIG. The second layer 12 is disposed at a position closest to the back sheet 21. The first layer 11 and the second layer 12 are directly adjacent to each other, and no other layer is interposed between the two layers.

  The 1st layer 11 is comprised from the resin bond nonwoven fabric. The resin bond nonwoven fabric is obtained by making the web into a nonwoven fabric by fixing the intersection of the fibers in the fiber web with an adhesive. Since the resin-bonded nonwoven fabric has a coarse structure with a large interfiber distance, it has a feature of high liquid permeability. In addition, due to the fact that the fibrous web is made into a non-woven fabric using an adhesive, the non-woven fabric has a relatively high rigidity, and thus has a feature that it is difficult to be deformed by an external force, that is, a wearer's body pressure. . Since the resin-bonded nonwoven fabric has these characteristics, it is preferential in the thickness direction faster than the liquid that has passed through the topsheet 20 diffuses in the lateral direction by disposing it in the uppermost layer of the absorbent body 10. It becomes transparent. Thereby, the absorbent article provided with the absorber 10 is excellent in spot absorptivity. Further, the liquid remaining in the first layer 11 is small. Spot absorptivity refers to the degree of diffusion of the absorbed liquid in the lateral direction when the absorbent article is viewed from the top sheet side, and high spot absorptivity is in the lateral direction of the liquid. The degree of diffusion of is said to be small. The high spot absorptivity of the absorbent article has an advantageous effect that it is easy to give the user an impression that the absorbent article is clean even after liquid absorption. Less liquid remaining in the first layer 11 has an advantageous effect of reducing the occurrence of unpleasant stuffiness in the wearing state of the absorbent article.

From the viewpoint of making the advantageous effects described above more remarkable, the resin bonded nonwoven fabric preferably has a basis weight of 10 g / m ² or more, particularly 20 g / m ² or more. Moreover, it is preferable that it is 200 g / m < ² > or less, especially 100 g / m < ² > or less. For example, the resin bond nonwoven fabric preferably has a basis weight of 10 g / m ² or more and 200 g / m ² or less, and more preferably 20 g / m ² or more and 100 g / m ² or less. From the same viewpoint, the resin-bonded nonwoven fabric preferably has a thickness under a pressure of 245 Pa of 0.5 mm or more, particularly 1.0 mm or more. Moreover, it is preferable that it is 10 mm or less, especially 5.0 mm or less. For example, the resin-bonded nonwoven fabric preferably has a thickness under a pressure of 245 Pa of 0.5 mm to 10 mm, particularly 1.0 mm to 5.0 mm.

  As described above, the resin-bonded non-woven fabric preferably has a large inter-fiber distance from the viewpoint of the liquid permeability along the thickness direction of the resin-bonded non-woven fabric having a coarse structure with a large inter-fiber distance. However, when the interfiber distance becomes excessively large, the composite water-absorbing polymer 14 included in the second layer 12 described later may fall off through the resin bond nonwoven fabric. From this point of view, the interfiber distance of the resin bonded nonwoven fabric is preferably smaller than the size of the composite water-absorbing polymer 14. The size of the composite water-absorbing polymer 14 is represented by a sieve opening diameter (μm) based on JISZ8801-1: 2006. The interfiber distance (μm) of the resin bonded nonwoven fabric is calculated from the following equation.

  The resin bond nonwoven fabric is comprised from 1 type, or 2 or more types of fibers. As this fiber, the fiber which consists of various thermoplastic resins can be used. The fiber may be comprised from single resin, and may be comprised from what blended 2 or more types of resin. Or you may be comprised from multicomponent composite fibers, such as a core sheath type and a side-by-side type. Examples of the thermoplastic resin include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, acrylic resins such as polyacrylate and polymethacrylate, and vinyl resins such as polyvinyl chloride and polystyrene. Resin etc. are mentioned.

  The fibers suitably formed from the above resins preferably have a fineness of 1.0 dtex or more, and more preferably 1.5 dtex or more. Further, it is preferably 15 dtex or less, and more preferably 10 dtex or less. For example, the fineness is preferably 1.0 dtex or more and 15 dtex or less, and more preferably 1.5 dtex or more and 10 dtex or less. By setting the fineness within this range, it is possible to easily obtain a resin-bonded nonwoven fabric having good liquid permeability along the thickness direction.

  It is preferable that the resin bond nonwoven fabric is hydrophilized. The hydrophilization treatment is achieved, for example, by kneading a hydrophilizing agent in a resin constituting the fiber and melt spinning the resin. Alternatively, it is also achieved by producing a resin-bonded nonwoven fabric using fibers that have not been subjected to a hydrophilic treatment, and then subjecting the nonwoven fabric to a hydrophilic treatment. If the resin bond nonwoven fabric has a surface energy (20 ° C.) of 43 mN / m or more, it is determined that it has an affinity for blood. The surface energy of the resin bond nonwoven fabric is measured by the following method. Prepare various standard solutions with known surface tension. When a measurement piece of resin bond nonwoven fabric is put in the standard solution, the resin bond nonwoven fabric has the surface tension value of the standard solution having the largest surface tension value among the standard solutions in which the measurement piece settles instantaneously. Surface energy. The size of the measurement piece of the resin bond nonwoven fabric is 4 mm long × 4 mm wide × 1-3 mm thick.

  Unlike the 2nd layer 12 mentioned later, the 1st layer which consists of a resin bond nonwoven fabric does not contain a water absorbing polymer or a composite water absorbing polymer.

  The 2nd layer 12 distribute | arranged to the back sheet 21 side adjacent to the 1st layer 11 which consists of a resin bond nonwoven fabric consists of a deposit layer which deposited the composite water absorbing polymer 14. FIG. The second layer 12 is substantially composed only of the composite water-absorbing polymer 14, and does not contain a single fiber material. “Substantially only composed of the composite water-absorbing polymer 14” means that the second layer 12 is composed of only the composite water-absorbing polymer 14 except for inevitable impurities. For example, when 95% by mass or more of the second layer 12 is composed of the composite water-absorbing polymer 14, it can be said that the second layer 12 is substantially composed of only the composite water-absorbing polymer 14. Inevitable impurities include, for example, an uncomplexed water-absorbing polymer or fiber material that is mixed in the process of producing the composite water-absorbing polymer 14.

  The “composite water-absorbing polymer” is a composite of a plurality of fiber materials per particle of one water-absorbing polymer. The term “composite” as used herein means that at least a part of the fiber length of the fiber material is embedded in the water-absorbing polymer particles, and at least a part of the plurality of fiber materials is water-absorbing. It is said that it is in the state which has come out from the particle of the property polymer. By disposing the second layer 12 made of the composite water-absorbing polymer 14 below the first layer 11 made of the resin-bonded nonwoven fabric, the fiber material of the composite water-absorbing polymer 14 has permeated the first layer 11. The liquid is smoothly transferred and the liquid absorption by the water-absorbing polymer is efficiently generated. Moreover, even if the composite water-absorbing polymer 14 swells rapidly due to the action of the fiber material of the composite water-absorbing polymer 14, gel blocking is difficult to occur. Further, due to the interaction between the fiber material of the composite water-absorbing polymer 14 and the constituent fibers of the resin-bonded nonwoven fabric of the first layer 11, the movement of the composite water-absorbing polymer 14 is regulated, and the dropout is effective. Is prevented. Furthermore, the presence of the fiber material on the surface of the water-absorbing polymer reduces the granular feeling caused by the water-absorbing polymer.

  The water-absorbing polymer refers to a substance that can retain water by becoming a gel by absorbing water. Examples of the water-absorbing polymer include a hydrogel material obtained by polymerizing a water-soluble ethylenically unsaturated monomer containing acrylic acid or acrylate as a main component and optionally adding a crosslinking agent. In addition, polyethylene oxide, polyvinylpyrrolidone, sulfonated polystyrene and polyvinylpyridine cross-linked product, saponified product of starch-poly (meth) acrylonitrile graft copolymer, starch-poly (meth) acrylic acid graft copolymer, starch-poly ( Examples thereof include hydrolysates of (meth) acrylic ester graft copolymers. These water-absorbing polymers can be used alone or in combination of two or more.

  The water-absorbing polymer may have various shapes known so far, for example, a spherical shape, a granular shape, a fibrous shape, a cocoon shape, and a lump shape. Further, the shape of the composite water-absorbing polymer 14 reflects the shape of the water-absorbing polymer before being combined. When the water-absorbing polymer before compounding is screened based on JISZ8801-1: 2006, it preferably passes 16 mesh, particularly 20 mesh, and preferably does not pass 200 mesh, particularly 150 mesh. For example, the water-absorbing polymer preferably passes 16 meshes and does not pass 200 meshes, more preferably passes 20 meshes and does not pass 150 meshes.

  Either natural fiber or synthetic fiber may be used as the fiber material combined with the water-absorbing polymer. Either a hydrophilic fiber or a hydrophobic fiber may be used. When using a hydrophobic fiber, it is preferable to hydrophilize the hydrophobic fiber before, during, or after complexing with the water-absorbing polymer. In particular, the fiber material is preferably made of hydrophilic fibers from the viewpoint that the liquid transmitted from the first layer 11 can be smoothly transferred to the composite water-absorbing polymer 14 in the second layer 12. The hydrophilic fiber mentioned here includes both a fiber made of a hydrophilic material and a fiber made of a hydrophobic material, and both fibers that have been subjected to a hydrophilic treatment and show hydrophilicity. Particularly preferred hydrophilic fibers are cellulose fibers which are fibers made of a hydrophilic material.

  Examples of the cellulose fiber used in the composite water-absorbing polymer 14 include natural cellulose fibers such as wood pulp, cotton pulp, and straw pulp such as softwood kraft pulp and hardwood kraft pulp. Alternatively, regenerated cellulose fibers such as rayon and cupra can be used. Furthermore, semi-synthetic cellulose fibers such as acetate can also be used.

  The fiber length used for the composite with the water-absorbing polymer may be longer or shorter than the size of the water-absorbing polymer. For example, the fiber length of the fiber material can be preferably 0.1 mm or more, more preferably 0.2 mm or more, preferably 50 mm or less, more preferably 40 mm. be able to. More preferably, the length of the fiber material is shorter than the size of the absorbent polymer. In particular, when cellulose fibers are used as the fiber material, it is preferable to have dimensions that pass through a 40-mesh sieve based on JISZ8801-1: 2006. By using cellulose fibers having such dimensions, the wettability of the surface of the water-absorbing polymer can be improved, and the liquid that has permeated from the first layer 11 is transferred to the composite water-absorbing polymer 14 in the second layer 12. Delivery can be performed more smoothly.

  The proportion of the fiber material in the composite water-absorbing polymer 14 is preferably 20% by mass or more, particularly preferably 30% by mass or more. Moreover, it is preferable that it is 80 mass% or less, especially 70 mass% or less. For example, the proportion of the fiber material in the composite water-absorbing polymer 14 is preferably 20% by mass or more and 80% by mass or less, and particularly preferably 30% by mass or more and 70% by mass or less. By containing the fiber material in this range, the composite water-absorbing polymer 14 can be effectively prevented from falling off. Moreover, a granular feeling can be reduced. Furthermore, the liquid that has permeated from the first layer 11 can be delivered more smoothly.

  For the same reason as described above, the proportion of the water-absorbing polymer in the composite water-absorbing polymer 14 is preferably 20% by mass or more, particularly preferably 30% by mass or more. Moreover, it is preferable that it is 80 mass% or less, especially 70 mass% or less. For example, the proportion of the water-absorbing polymer in the composite water-absorbing polymer 14 is preferably 20% by mass or more and 80% by mass or less, and particularly preferably 30% by mass or more and 70% by mass or less.

  The ratio of the fiber material and the water-absorbing polymer in the composite water-absorbing polymer 14 can be measured by measuring the weight in a dry state, dissolving and removing the water-absorbing polymer, drying it, and measuring the weight of the fiber material alone. Specifically, first, the weight (a) of the composite water-absorbing polymer 14 is measured. Thereafter, the composite water-absorbing polymer 14 is sealed in a mesh bag (nylon net, 250 mesh or more) and immersed in an aqueous solution of ascorbic acid and riboflavin overnight. Then, the composite water-absorbing polymer 14 is exposed to sunlight together with the soaked mesh bag. Thereafter, the mesh bag is washed with water, and the weight of the bag contents is measured (b). Here, since a is the total weight of the composite water-absorbing polymer 14, and b is the weight of the fiber material in the composite water-absorbing polymer 14, the weight of the water-absorbing polymer can be calculated by ab. The ratios of the fiber material and the water-absorbing polymer in the composite water-absorbing polymer 14 can be obtained by b / a and (ab) / a, respectively.

Further, the use amount of the composite water-absorbing polymer 14 is preferably 50 g / m ² or more, particularly preferably 100 g / m ² or more, more preferably 400 g / m ² or less, and particularly preferably 300 g / m ² or less. For example, the amount of the composite water-absorbing polymer 14 used is preferably 50 g / m ² or more and 400 g / m ² or less, and more preferably 100 g / m ² or more and 300 g / m ² or less. By using the composite water-absorbing polymer 14 in this range, it is possible to obtain the absorbent body 10 having a sufficient absorption retention capacity of the liquid. The bulk of the composite water-absorbing polymer 14 increases as the fiber length of the fiber material used for the composite water-absorbing polymer 14 increases, and decreases as the fiber length decreases. Therefore, in general, in order to configure the second layer 12 from the composite water-absorbing polymer 14, the amount of the composite water-absorbing polymer used is small when the fiber length of the fiber material is long and large when the fiber length is short. Become.

  From the standpoint of further preventing gel blocking, it is preferable that the composite water-absorbing polymers 14 are not joined in the second layer 12.

The composite water-absorbing polymer 14 can be manufactured by a conventionally known method. For example, it can be suitably manufactured by the method described in Patent Documents 1 and 2 described above. Specifically, there is a method in which the water-absorbing polymer is combined with the fiber material at the monomer stage. Instead of this method, it is also possible to employ a method in which a water-absorbing polymer is produced in advance by polymerization and then combined with a fiber material. In particular, it is preferable to employ any one of the following methods (i) to (iii) because the composite water-absorbing polymer 14 in a state in which a part of the fiber material is out of the water-absorbing polymer can be successfully produced.
(I) A method in which a water-absorbing polymer obtained by polymerization absorbs water or a water-containing solvent and is swollen with a fiber material, and then dried and pulverized.
(Ii) A polymer obtained by mixing and dispersing a fiber material in a system in which a crosslinking agent is added to a water-soluble ethylenically unsaturated monomer as necessary to obtain a polymer, and the polymer is dissolved after drying. How to fine or crush.
(Iii) A fiber material is dispersed in a system in which a crosslinking agent is added to a water-soluble ethylenically unsaturated monomer as needed, and after papermaking and pressing, a polymer is obtained by polymerization, and the polymer is dried. How to defibrate.

  In the absorbent body 10, the mass ratio between the first layer 11 and the second layer 12 is 150 parts by mass or more, particularly 200 parts by mass or more for the second layer 12 with respect to 100 parts by mass of the first layer 11. It is preferably 800 parts by mass or less, more preferably 600 parts by mass or less. For example, it is preferable to use the second layer 12 at a ratio of 150 parts by mass or more and 800 parts by mass or less with respect to the first layer 11 of 100 parts by mass, and the second layer 12 at a ratio of 200 parts by mass or more and 600 parts by mass or less. More preferably, it is used.

  As the decoy shown in FIG. 1, the absorber 10 of the present embodiment has a two-layer structure, and therefore the first layer 11 and the second layer 12 are in direct contact with each other. In this case, the opposing surfaces of both layers 11 and 12 may be joined by a predetermined means or may not be joined. The term “joining” as used herein refers to, for example, bonding with an adhesive, thermal fusion, ultrasonic bonding, or the like. If the opposing surfaces of both layers 11 and 12 are bonded together, liquid transfer between the layers 11 and 12 is inhibited when an external force is applied to the article and deformation occurs in the mounted state of the absorbent article. Since it becomes difficult to produce a space | gap, it is preferable. However, when the layers 11 and 12 are joined, the absorbent body 10 tends to be hard, which may contribute to a decrease in fit and wearing feeling of the absorbent article. On the other hand, in the absorbent body 10 of the present embodiment, the fiber material of the composite water-absorbing polymer 14 of the second layer 12 is easily entangled with the first layer 11 made of a resin-bonded nonwoven fabric that is a relatively hard material. Therefore, even if the two layers 11 and 12 are not joined, there is an advantage that when the absorber 10 is deformed, a gap is hardly generated between the two layers 11 and 12. Further, if the layers 11 and 12 are not joined, there is no inhibition of liquid migration caused by joining means such as an adhesive, so that the liquid that has permeated the first layer 11 is smoothly second. This is advantageous because it leads to the layer 12 and the liquid absorption time is further shortened.

  FIG. 2 schematically shows the state of liquid permeation / absorption when the liquid is excreted in the absorber 10 of the present embodiment. 2A and 2B schematically show a longitudinal section of the absorbent body 10. FIG. 2A shows a state in which the liquid L excreted in the top sheet 11 is transmitted through the first layer 11 of the absorber 10. As described above, the first layer 11 made of the resin bonded nonwoven fabric has a property of high liquid permeability, so that the liquid L is in the thickness direction rather than diffusing in the lateral direction of the first layer 11. Preferentially transparent. As a result, the liquid L passes through the first layer 11 in a spot shape. Therefore, in the region other than the site where the liquid L is excreted, the first layer 11 is not contaminated by the liquid L. Due to this, when the absorbent article is viewed from the side of the top sheet 20, the area where the stain is caused by the liquid L is suppressed to a small size, thereby giving the user an impression that the absorbent article is clean. Cheap.

  FIG. 2B shows the state of permeation / diffusion of the liquid L in the second layer 12. The liquid transferred from the first layer 11 to the second layer 12 is quickly guided to the composite water-absorbing polymer 14 by the action of the fiber material in the composite water-absorbing polymer 14 included in the second layer 12. In addition, since the composite water-absorbing polymer 14 has a large number of fiber materials concentrated on the surface thereof, and a capillary force is generated due to this, the liquid L diffuses in the lateral direction using the capillary force as a driving force. Further, due to the capillary force, the liquid L is also retained between the fiber materials. Thereby, the entire composite water-absorbing polymer 14 contained in the second layer 12 is used for absorbing and holding the liquid L. As a result, the proportion of the composite water-absorbing polymer 14 that does not contribute to the absorption and retention of the liquid L is reduced, and the composite water-absorbing polymer 14 is effectively utilized.

  The diffusion of the liquid L in the lateral direction in the second layer 12 is likely to occur mainly in a portion near the back sheet 21 among the portions in the thickness direction of the second layer 12. Therefore, when the back sheet 12 has moisture permeability, the liquid L diffused in the portion of the second layer 12 near the back sheet 21 is preferably evaporated through the moisture permeable back sheet 12. The moisture-permeable back sheet is generally formed into a porous structure by molding a resin composition obtained by kneading powder into a thermoplastic resin into a film shape and stretching the molded body uniaxially or biaxially. .

  FIG. 3 shows another embodiment of the present invention. The absorber 10A shown in the figure has a three-layer structure. Of the three-layer structure, the first layer 11 and the second layer 12 are the same as those in the above-described embodiment. In addition to these two layers, the absorber 10 </ b> A has a third layer 13. The third layer 13 is disposed between the back sheet 21 and the second layer 12.

  The third layer 13 is composed of a nonwoven fabric. This nonwoven fabric may use either natural fibers or synthetic fibers as its constituent fibers. Either a hydrophilic fiber or a hydrophobic fiber may be used. When a hydrophobic fiber is used, the hydrophobic fiber may be hydrophilized. When the nonwoven fabric of the third layer 13 is used in a hydrophobic state, the liquid easily diffuses in the lateral direction in the second layer 12. In this case, the liquid spreading area is small on the surface of the absorber 10A facing the lowermost back sheet, that is, the surface facing the back sheet of the third layer 13 (see, for example, Examples 4 and 6 described later). ). On the other hand, when the nonwoven fabric of the third layer 13 is used in a hydrophilic state, the liquid that has migrated from the second layer 12 easily diffuses in the lateral direction in the third layer 13. In this case, the liquid spreading area on the surface facing the lowermost back sheet of the absorber 10A, that is, the surface facing the back sheet of the third layer 13, is larger than the liquid spreading area on the surface of the second layer 12. (See, for example, Examples 5, 7, and 8 to be described later). In addition, although the fiber which has hydrophilicity consists of a fiber which consists of a hydrophilic material, and a hydrophobic material, both the fiber which has been hydrophilized and shows hydrophilicity is included.

The nonwoven fabric of the third layer 13 preferably has a basis weight of 10 g / m ² or more, particularly 15 g / m ² or more. Further, it is preferably 80 g / m ² or less, particularly preferably 60 g / m ² or less. For example, the basis weight of the nonwoven fabric is preferably 10 g / m ² or more and 80 g / m ² or less, and more preferably 15 g / m ² or more and 60 g / m ² or less. From the same viewpoint, when the nonwoven fabric is a resin-bonded nonwoven fabric, the thickness under a pressure of 245 Pa is preferably 0.5 mm or more, particularly 1.0 mm or more. Moreover, it is preferable that it is 10 mm or less, especially 5.0 mm or less. For example, the resin-bonded nonwoven fabric preferably has a thickness under a pressure of 245 Pa of 0.5 mm to 10 mm, particularly 1.0 mm to 5.0 mm. Moreover, when the nonwoven fabric is a nanofiber nonwoven fabric or an ultrafine fiber nonwoven fabric, the thickness under a pressure of 245 Pa is preferably 0.01 mm or more, particularly 0.05 mm or more. Moreover, it is preferable that it is 0.5 mm or less, especially 0.3 mm or less. For example, the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric preferably has a thickness under a pressure of 245 Pa of 0.01 mm to 0.5 mm, particularly 0.05 mm to 0.3 mm. By setting the basis weight and thickness of the nonwoven fabric in this way, the liquid can be efficiently diffused in the lateral direction in the second layer 12 (when the third layer is hydrophobic). Further, the liquid that has permeated from the second layer 12 can be efficiently diffused in the lateral direction in the third layer 13 (when the third layer is hydrophilic).

  The nonwoven fabric of the third layer 13 is composed of one type or two or more types of fibers. As the fiber, when a fiber made of a thermoplastic resin is used, the fiber may be composed of a single resin or may be composed of a blend of two or more resins. Or you may be comprised from multicomponent composite fibers, such as a core sheath type and a side-by-side type. Examples of the thermoplastic resin include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, acrylic resins such as polyacrylate and polymethacrylate, and vinyl resins such as polyvinyl chloride and polystyrene. Resin etc. are mentioned.

  When the nonwoven fabric of the third layer 13 is a resin bond nonwoven fabric, the constituent fibers thereof preferably have a fineness of 1.0 dtex or more, and more preferably 1.5 dtex or more. Further, it is preferably 15 dtex or less, and more preferably 10 dtex or less. For example, the fineness of the resin bonded nonwoven fabric is preferably 1.0 dtex or more and 15 dtex or less, and more preferably 1.5 dtex or more and 10 dtex or less. Moreover, when the nonwoven fabric of the 3rd layer 13 is an ultrafine fiber nonwoven fabric, it is preferable that the fiber diameter is 500 nm or more, and, as for the constituent fiber, it is more preferable that it is 1000 nm or more. Moreover, it is preferable that it is 3000 nm or less, and it is still more preferable that it is 2500 nm or less. For example, the fiber diameter of the ultrafine fiber nonwoven fabric is preferably 500 nm or more and 3000 nm or less, and more preferably 1000 nm or more and 2500 nm or less. By using fibers having fineness in this range, the liquid can be efficiently diffused in the lateral direction in the second layer 12 (when the third layer is hydrophobic), and the liquid that has permeated from the second layer 12 Can be efficiently diffused in the lateral direction in the third layer 13 (when the third layer is hydrophilic).

  In particular, as the constituent fibers of the nonwoven fabric of the third layer 13, it is preferable to use ultrafine fibers called nanofibers, which have a smaller fiber diameter than the ultrafine fibers. By using the nanofiber, the liquid transmitted from the second layer 12 can be efficiently diffused in the lateral direction in the third layer. The nanofiber is generally 10 nm or more and 3000 nm or less, particularly 10 nm or more and 1000 nm or less when the thickness is represented by a circle equivalent diameter. The thickness of the nanofiber is observed, for example, by observing the fiber at a magnification of 10,000 times by scanning electron microscope (SEM) observation. From the two-dimensional image, defects (nanofiber lump, nanofiber intersection, polymer droplet) are observed. ) Is arbitrarily selected, and a line perpendicular to the longitudinal direction of the fiber is drawn to measure the fiber diameter directly.

  When the nonwoven fabric of the 3rd layer 13 is a nonwoven fabric which consists of a nanofiber or an ultrafine fiber, it is preferable that the nanofiber nonwoven fabric or an ultrafine fiber nonwoven fabric has hydrophilicity. As a result, the advantageous effects obtained by using nanofibers or ultrafine fibers become more prominent, and the liquid that has permeated from the second layer 12 is more efficiently diffused laterally in the third layer. be able to.

  As the nonwoven fabric of the third layer 13, those produced by various methods can be used. For example, a spunbond nonwoven fabric, an air-through nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, a resin bond nonwoven fabric, a needle punch nonwoven fabric, a point bond nonwoven fabric, and the like can be given. Moreover, a nonwoven fabric can also be manufactured by a wet papermaking method. In particular, when producing a nonwoven fabric composed of the above-described nanofiber or ultrafine fiber, it is preferable to employ the melt blown method. Details of the melt blown method are described in, for example, Japanese Patent Application Laid-Open No. 4-91212. As another method for producing a nonwoven fabric composed of nanofibers or ultrafine fibers, an electrospinning method (electrospinning method) can also be employed. The electrospinning method is a well-known method for producing ultrafine fibers. For example, it is described in JP-A-2005-290610, JP-A-2008-179629, JP-A-2010-121221, JP-A-2010-168722, JP-A-2012-122176, and the like.

  In particular, when a resin bond nonwoven fabric is used as the nonwoven fabric 15 of the third layer 13, if the liquid cannot be absorbed and held by the composite water-absorbing polymer 14 of the second layer 12, the liquid that could not be held is the first layer 11. This is preferable because it diffuses in the lateral direction in the third layer 13 without going back to the side.

  The third layer 13 is directly adjacent to the second layer 12, and no other layer is interposed between the two layers. In this case, the opposing surfaces of both layers 12 and 13 may be joined by a predetermined means or may not be joined. If the opposing surfaces of both layers 12 and 13 are bonded together, the liquid transfer between the layers 12 and 13 is inhibited when an external force is applied to the article and deformation occurs when the absorbent article is mounted. Although it is preferable because voids are less likely to occur, the absorber 10 tends to be hardened by joining the layers 12 and 13 together. On the other hand, in the absorbent body 10A of the present embodiment, the fiber material of the composite water-absorbing polymer 14 of the second layer 12 is easily entangled with the constituent fibers of the nonwoven fabric of the third layer 13, and mechanical bonding force is generated. Since it is easy, even if the layers 12 and 13 are not joined, there is an advantage that when the absorber 10A is deformed, voids are unlikely to be formed in the layers 12 and 13. In addition, if the layers 12 and 13 are not joined, there is no inhibition of fluid migration caused by joining means such as an adhesive. Therefore, smooth fluid flow from the second layer 12 to the third layer 13 is prevented. Transition takes place.

  In addition, the nonwoven fabric which comprises the 3rd layer 13, like the resin bond nonwoven fabric which comprises the 1st layer 11, does not contain a water absorbing polymer or a composite water absorbing polymer.

  The absorbent article provided with the absorbers 10 and 10A described above is particularly excellent in spot absorptivity, and is therefore suitable as a sanitary product, particularly a sanitary napkin for daytime use.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, the absorbent article provided with the absorbent body 10 of the above-described embodiment is particularly suitable as a sanitary napkin as described above, but other absorbent articles such as disposable diapers, panty liners, incontinence pads, and the like. The same can be applied.

This invention discloses the following absorbent articles further regarding embodiment mentioned above.
<1>
In an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable or liquid-permeable back sheet, and a liquid-retaining absorbent disposed between both sheets,
The absorber has a laminated structure in which two or more layers are laminated,
A first layer made of a resin bonded nonwoven fabric is disposed at a position closest to the surface sheet;
Absorbent article in which a second layer made of a composite water-absorbing polymer, in which a fiber material is embedded, is disposed on at least a part of the surface of the water-absorbing polymer between the back sheet and the first layer. .

<2>
The amount of the composite water-absorbing polymer used in the second layer comprising the composite water-absorbing polymer is preferably 50 g / m ² or more, particularly preferably 100 g / m ² or more, and 400 g / m ² or less, particularly 300 g / m ² or less. The absorbent article according to <1>, which is more preferably present.
<3>
The resin bonded nonwoven fabric preferably has a basis weight of 10 g / m ² or more, particularly preferably 20 g / m ² or more, more preferably 200 g / m ² or less, and particularly preferably 100 g / m ² or less <1> or The absorbent article as described in <2>.
<4>
Any of the above <1> to <3>, wherein the resin-bonded nonwoven fabric has a thickness under a pressure of 245 Pa of preferably 0.5 mm or more, particularly preferably 1 mm or more, and preferably 10 mm or less, particularly preferably 5 mm or less. 2. The absorbent article according to 1.
<5>
The absorbent article according to any one of <1> to <4>, wherein a distance between fibers of the resin bond nonwoven fabric is smaller than a size of the composite water-absorbing polymer.
<6>
The fineness of the constituent fibers of the resin bond nonwoven fabric is preferably 1.0 dtex or more, more preferably 1.5 dtex or more, more preferably 15 dtex or less, and even more preferably 10 dtex or less <1 The absorbent article according to any one of> to <5>.
<7>
The absorbent article according to any one of <1> to <6>, wherein the resin-bonded nonwoven fabric is hydrophilized.

<8>
The absorbent article according to any one of <1> to <7>, wherein the first layer made of a resin-bonded nonwoven fabric does not contain the water-absorbing polymer and the composite water-absorbing polymer.
<9>
The absorbent article according to any one of <1> to <8>, wherein the fiber material is cellulose fiber.
<10>
The absorbent article according to any one of <1> to <9>, wherein the fiber material has a size that passes through a 40-mesh sieve based on JISZ8801-1: 2006.
<11>
The absorbent article according to any one of <1> to <10>, wherein 95% by mass or more of the second layer 12 is composed of the composite water-absorbing polymer.
<12>
In the composite water-absorbing polymer, at least a part of the fiber length of the fiber material is embedded in particles of the water-absorbing polymer, and at least a part of the plurality of fiber materials is The absorbent article according to any one of <1> to <11>, wherein the absorbent article is in a state of protruding from the water-absorbing polymer particles.

<13>
When the water-absorbing polymer before compounding is screened based on JISZ8801-1: 2006, it preferably passes 16 mesh, particularly 20 mesh, and preferably does not pass 200 mesh, particularly 150 mesh. The absorbent article according to any one of> to <12>.
<14>
The fiber length of the fiber material is preferably 0.1 mm or more, more preferably 0.2 mm or more, preferably 50 mm or less, more preferably 40 mm, any one of <1> to <13> Or an absorbent article according to claim 1.
<15>
The absorbent article according to any one of <1> to <14>, wherein the length of the fiber material is shorter than the size of the absorbent polymer.
<16>
The absorbent article according to any one of <1> to <15>, wherein cellulose fiber is used as the fiber material, and the cellulose fiber has a size that passes through a 40-mesh sieve based on JISZ8801-1: 2006.
<17>
<1> The proportion of the fiber material in the composite water-absorbing polymer is preferably 20% by mass or more, particularly preferably 30% by mass or more, and more preferably 80% by mass or less, particularly preferably 70% by mass or less. Thru | or <16> any one of the absorptive articles.

<18>
The proportion of the water-absorbing polymer in the composite water-absorbing polymer is preferably 20% by mass or more, particularly preferably 30% by mass or more, and more preferably 80% by mass or less, particularly preferably 70% by mass or less. > Absorptive article given in any 1 of <17>.
<19>
The absorbent article according to any one of <1> to <18>, wherein the composite water-absorbing polymer is produced by any one of the following methods (i) to (iii):
(I) A method in which the water-absorbing polymer obtained by polymerization absorbs water or a water-containing solvent and is swollen with the fiber material, and then dried and pulverized.
(Ii) A polymer obtained by mixing and dispersing the fiber material in a system in which a crosslinking agent is added to a water-soluble ethylenically unsaturated monomer as necessary, to obtain a polymer, and after drying the polymer Defibration or pulverization method.
(Iii) The fiber material is dispersed in a system in which a crosslinking agent is added to a water-soluble ethylenically unsaturated monomer as necessary, and after papermaking and pressing, a polymer is obtained by polymerization, and the polymer is dried. How to defibrate later.
<20>
The absorbent article according to any one of <1> to <19>, wherein a third layer is disposed between the back sheet and the second layer.
<21>
The basis weight of the nonwoven fabric of the third layer is preferably 10 g / m ² or more, particularly preferably 15 g / m ² or more, and preferably 80 g / m ² or less, particularly preferably 60 g / m ² or less <1. The absorbent article according to any one of> to <20>.
<22>
The absorbent article according to <21>, wherein a third layer made of a nanofiber nonwoven fabric or an ultrafine fiber nonwoven fabric is disposed between the back sheet and the second layer.

<23>
The absorbent article according to <22>, wherein the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric is produced by an electrospinning method.
<24>
The absorbent article according to <22> or <23>, wherein the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric has hydrophilicity.
<25>
The nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric preferably has a thickness under a pressure of 245 Pa of 0.01 mm or more, particularly 0.05 mm or more, and preferably 0.5 mm or less, particularly 0.3 mm or less. The absorbent article according to any one of <22> to <24>.
<26>
The constituent fiber of the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric preferably has a fiber diameter of 500 nm or more, more preferably 1000 nm or more, and preferably 3000 nm or less, and more preferably 2500 nm or less. The absorbent article according to any one of <22> to <25>.
<27>
The nanofiber of the nanofiber nonwoven fabric has an absorbent article according to any one of <22> to <26>, wherein the thickness is expressed in terms of a circle equivalent diameter, which is 10 nm to 3000 nm, particularly 10 nm to 1000 nm. .

<28>
The absorbent article according to <21>, wherein a third layer made of a resin-bonded nonwoven fabric is disposed between the back sheet and the second layer.
<29>
The absorbent article according to <28>, wherein the resin-bonded nonwoven fabric has a thickness under a pressure of 245 Pa of preferably 0.5 mm or more, particularly preferably 1 mm or more, and preferably 10 mm or less, particularly preferably 5 mm or less.
<30>
The constituent fibers of the resin bond nonwoven fabric preferably have a fineness of 1.0 dtex or more, more preferably 1.5 dtex or more, and preferably 15 dtex or less, more preferably 10 dtex or less. The absorbent article as described in <28> or <29>.
<31>
The absorbent article according to any one of <1> to <30>, wherein the composite water-absorbing polymers constituting the second layer are in a non-bonded state.
<32>
The absorbent article according to any one of <1> to <31>, wherein the first layer and the second layer are located adjacent to each other and both layers are in a non-bonded state.

<33>
The absorbent article according to any one of <20> to <32>, wherein the second layer and the third layer are located adjacent to each other, and both layers are in a non-bonded state.
<34>
The absorbent article according to any one of <1> to <33>, wherein the back sheet has moisture permeability.
<35>
The absorbent article according to any one of <1> to <34>, wherein the periphery of the laminated structure is not covered with a liquid-permeable sheet.
<36>
The absorbent article according to any one of <1> to <35>, which is a sanitary napkin, a disposable diaper, a panty liner, or an incontinence pad.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “mass%”.

[Example 1]
In this example, the absorbent body 10 having the structure shown in FIG. 1 was manufactured by the following procedure.
(1) Manufacture of the first layer 11 Resin bond nonwoven fabric obtained by thinly cutting a trade name “Traveron IJ180R” and a basis weight of 300 g / cm ² using a product name “Slicer A-70LP” manufactured by Hakura Seiki Co., Ltd. Was made. When the surface energy (20 ° C.) of this nonwoven fabric was measured by the above-mentioned method, it was 73 mN / m, and it was confirmed that it had affinity for blood. The thickness of this nonwoven fabric under a pressure of 245 Pa was 3.1 mm, and the interfiber distance was 260 μm. The basis weight was as shown in Table 1.

(2) Manufacture of the composite water-absorbing polymer 14 of the second layer 12 To the water-absorbing polymer taken out from the absorber of the trade name “Merry's Sarasara Air-Through M size” manufactured by Kao Corporation, water at a mass ratio of 10 times is added and mixed with a kneader. And swollen evenly. To this, Nippon Paper Industries Co., Ltd., trade name “KC Flock W-400S” (fine cellulose fiber, 400 mesh pass 90% or more) was added, kneaded, dried and sprayed on the basis weight shown in Table 1 to obtain a composite water absorption. Polymer 14 was produced. The proportion of the fiber material in the composite water-absorbing polymer was 50%, and the proportion of the water-absorbing polymer was 50%.

(3) Manufacture of absorber 10 On the 2nd layer 12 obtained by the above (2), the 1st layer 11 obtained by the above (1) was piled up in the non-joining state. Both layers were lightly pressed to obtain the intended absorber 10. The absorber was formed in a square shape with a side of 55 mm.

[Example 2]
In this example, as the resin-bonded nonwoven fabric in the above (1) of Example 1, the one obtained by slicing to the basis weight shown in Table 1 using the trade name TRAVERON AF95A manufactured by Kanai Kangyo Kogyo Co., Ltd. was used. Except this, it carried out similarly to Example 1, and obtained the absorber 10.

Example 3
In this example, the resin bond nonwoven fabric in (1) of Example 1 was sliced into the basis weight shown in Table 1 using a trade name TRAVERON AF50A manufactured by Kanai Important Industry Co., Ltd. Except this, it carried out similarly to Example 1, and obtained the absorber 10.

Example 4
In this example, an absorbent body 10A having the structure shown in FIG. 3 was manufactured by the following procedure.
(1) Production of first layer 11 and second layer 12 The same procedure as in Example 1 was performed.

(2) Production of third layer 13 The third layer 13 was the same as the first layer 11.

(3) Manufacture of Absorbent Body 10A On the third layer 13 obtained in (2) above, the composite water-absorbing polymer of the second layer 12 is dispersed, and the first layer 11 is further unbonded thereon. Superimposed. These layers were lightly pressed to obtain the intended absorber 10A.

Example 5
In this example, as the resin-bonded nonwoven fabric of the first layer 11, those having the basis weight shown in Table 1 similar to that of Example 1 were used. Moreover, it replaced with the resin bond nonwoven fabric of the 3rd layer 13 used in Example 4, and used the ultrafine fiber nonwoven fabric. The ultrafine fiber nonwoven fabric was manufactured by the following method.

  The ultrafine fiber nonwoven fabric manufacturing apparatus 100 shown in FIG. 4 was used. The apparatus 100 shown in the figure includes a meltblown apparatus 110. Furthermore, the ultrafine fiber nonwoven fabric manufacturing apparatus 100 includes a transport conveyor 125. The melt blown device 110 includes a casing 111 having a main body 112 and a die 113, and a discharge nozzle 114 attached to the die 113. A hopper 19 is attached to the main body part 112, and PP as a raw material is supplied therefrom. Moreover, the main-body part 112 is provided with the cylinder and the screw (all are not shown) arrange | positioned in this cylinder.

  Using the ultrafine fiber nonwoven fabric manufacturing apparatus 100 having the above configuration, PP was melted at a heating temperature of a cylinder in the casing 111 of the melt blown apparatus 110 at 250 ° C. A hydrophilizing agent of 10% with respect to the mass of PP was added and melt kneading was performed in the casing. As the hydrophilizing agent, an ethylene oxide adduct of stearyl alcohol was used. The melted PP was discharged from the discharge nozzle 114 at a discharge amount of 300 g / h (indicated by symbol R in FIG. 4). An air flow heated to 300 ° C. was ejected from an air blowing nozzle (not shown) adjacent to the discharge nozzle 114 at a flow rate of 300 L / min. The PP ultrafine fibers conveyed in the air stream were made of PP mesh and conveyed by a conveyor 125 that circulates at 1 m / min. The ambient environment was 25 ° C. and 50% RH. The thickness of the ultrafine fiber in the ultrafine fiber nonwoven fabric thus obtained was 1600 nm as measured with an electron microscope. The basis weight of the ultrafine fiber nonwoven fabric was as shown in Table 1.

Example 6
In this example, the ultrafine fiber nonwoven fabric used in Example 5 was used without adding a hydrophilizing agent and remained hydrophobic. Moreover, as the resin bond nonwoven fabric of the 1st layer 11, the thing of the basic weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained absorber 10A.

Example 7
In this example, KC Flock W-100S (fine cellulose fiber, 100 mesh pass 90% or more) was used in place of the fiber material used in the production of the composite water-absorbing polymer in Example 5. Moreover, as the resin bond nonwoven fabric of the 1st layer 11, the thing of the basic weight shown in Table 1 was used. Except this, it carried out similarly to Example 5, and obtained absorber 10A.

Example 8
In this example, KC Flock W-50S (fine cellulose fiber, 42 mesh pass 90% or more) was used in place of the fiber material used in the production of the composite water-absorbing polymer in Example 5. Moreover, as the resin bond nonwoven fabric of the 1st layer 11, the thing of the basic weight shown in Table 1 similar to Example 1 was used. Except this, it carried out similarly to Example 5, and obtained absorber 10A.

[Comparative Example 1]
In this comparative example, wet pulp sheets having a basis weight shown in Table 1 were used as the first layer 11 and the third layer 13. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 2]
In this comparative example, the third layer 13 was not used. An air-through nonwoven fabric was used as the first layer 11. This air-through nonwoven fabric was made from a core-sheath type composite fiber having a fineness of 2.3 dtex, whose core is made of polyethylene terephthalate and whose sheath is made of polyethylene. Table 1 shows the basis weight of this air-through nonwoven fabric. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 3]
In this comparative example, the third layer was not used. The resin-bonded nonwoven fabric of the first layer 11 was the same as in Example 1. Further, the composite water-absorbing polymer of the second layer 12 was not used, and instead, a normal water-absorbing polymer (the same as the water-absorbing polymer before complexing used in Example 1) was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 4]
The absorbent sheet was removed by carefully peeling off the top sheet and the back sheet from a commercially available disposable diaper “Paper's Cruisers Diapers size 5” (manufactured by The Procter & Gamble Company, sales location: USA). The resulting structure of the absorber, from the surface side in this order, resin bonded nonwoven layer having a basis weight of 60 g / ^{m 2,} crosslinked cellulose layer having a basis weight of 200 g / ^{m 2,} spun bond having a basis weight of 10 g / ^{m 2} - meltblown - Span ^They were a bond nonwoven fabric (hereinafter referred to as “SMS nonwoven fabric”) layer, a water-absorbing polymer (non-complexed) layer having a basis weight of 250 g / m ^{2, and} an SMS nonwoven fabric layer having a basis weight of 10 g / m ² . Further, the water-absorbing polymer and the SMS nonwoven fabric sandwiching the water-absorbing polymer layer were bonded by a hot melt adhesive. And the absorber was cut out in the shape of a 55 mm square. This absorber was used as Comparative Example 4.

[Comparative Example 5]
In this comparative example, the composite water-absorbing polymer of the second layer 12 was not used, but a normal water-absorbing polymer (same as the water-absorbing polymer before complexing used in Example 1) was used instead. Moreover, as the resin bond nonwoven fabric of the 1st layer 11, the thing of the basic weight shown in Table 1 was used. Except this, it carried out similarly to Example 5, and obtained the absorber.

[Evaluation]
About the absorber obtained by the Example and the comparative example, the spreading | diffusion area of a liquid was measured with the following method, and a result is shown in the following Table 1.

[Liquid diffusion area]
On the surface of the first layer, the surface of the second layer, and the back surface of the lowermost layer (that is, the back surface of the second layer (in the case of a two-layer structure) or the back surface of the third layer (in the case of a three-layer structure)) The diffusion area of the liquid was determined by the following procedure. The absorber was cut into a 55 mm square so as to be parallel to the longitudinal direction and the width direction, and a measurement sample was produced. On the 1st layer in a measurement sample, the acrylic board of the width which covers this was mounted. A cylinder having a diameter of 10 mm was provided at the center of the acrylic plate, and the acrylic plate was open in the cylinder. Under the condition that the pressure by the acrylic plate was 650 Pa, 3 g of horse blood was injected into the cylinder at once. The time until the injected horse blood was completely absorbed was measured, and this was taken as the absorption time.
After 3 minutes from the end of the injection, the acrylic plate was removed, and the diffusion area of the liquid on the surface of the first layer, the surface of the second layer, and the back surface of the lowermost layer in the absorber was measured using image software (Media Cybernetics, Inc. (Trade name “Image-Pro Plus”).
The equine blood was adjusted to a viscosity of 8.0 ± 0.1 cP (25 ° C.). The viscosity was adjusted by adding plasma and blood cell components extracted from horse blood itself to horse blood. Plasma and blood cell components are a supernatant portion and a sediment portion, respectively, when horse blood is left and separated.

  As is clear from the results shown in Table 1, in each example, the liquid diffusion area on the surface of the first layer is as small as 1/2 or less of the liquid diffusion area on the surface of the second layer, and the liquid is sufficiently absorbed by the second layer. However, it is spot-absorbed and gives you a sense of security. In Examples 5 and 7, the diffusion area of the lowermost layer is 3.5 times or more that of the surface of the first layer, and it can be seen that the spot absorptivity is particularly excellent. On the other hand, in Comparative Examples 1 and 2 in which the first layer made of the resin bonded nonwoven fabric was not used, the diffusion area in the first layer was large and the second layer could not be utilized. It can be seen that also in Comparative Examples 3 and 5 in which the composite water-absorbing polymer is not used in the second layer, the liquid diffusion area becomes large. Comparative Example 4 also did not use the composite water-absorbing polymer, but the diffusion area on the surface of the first layer was small due to the presence of the crosslinked cellulose layer. However, the diffusion area on the surface of the first layer is larger than ½ of the diffusion area on the surface of the second layer, that is, the effect of diffusing the liquid in the lower layer is small, and Comparative Example 4 has a sufficiently low spot absorptivity. I understand.

DESCRIPTION OF SYMBOLS 10 Absorber 11 1st layer 12 2nd layer 13 3rd layer 14 Composite water-absorbing polymer 15 Non-woven fabric 20 Top sheet 21 Back sheet

Claims (10)

In an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable or liquid-permeable back sheet, and a liquid-retaining absorbent disposed between both sheets,
The absorber has a laminated structure in which two or more layers are laminated,
A first layer made of a resin bonded nonwoven fabric is disposed at a position closest to the surface sheet;
Absorbent article in which a second layer made of a composite water-absorbing polymer, in which a fiber material is embedded, is disposed on at least a part of the surface of the water-absorbing polymer between the back sheet and the first layer. .   The absorbent article according to claim 1, wherein the fiber material is cellulose fiber.   The absorptive article according to claim 1 or 2 in which said textile material has a size which passes a 40-mesh sieve based on JISZ8801-1: 2006.   The absorbent article as described in any one of Claim 1 thru | or 3 with which the 3rd layer which consists of a nanofiber nonwoven fabric or an ultrafine fiber nonwoven fabric is distribute | arranged between the said back surface sheet and the 2nd layer.   The absorbent article according to claim 4, wherein the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric is hydrophilic.   The absorbent article as described in any one of Claim 1 thru | or 3 with which the 3rd layer which consists of a resin bond nonwoven fabric is distribute | arranged between the said back surface sheet and the 2nd layer.   The absorbent article according to any one of claims 1 to 6, wherein the composite water-absorbing polymers constituting the second layer are in a non-bonded state.   The absorbent article according to any one of claims 1 to 7, wherein the first layer and the second layer are located adjacent to each other, and both the layers are in a non-bonded state.   The absorbent article according to any one of claims 4 to 8, wherein the second layer and the third layer are located adjacent to each other, and both layers are in a non-bonded state.   The absorptive article according to any one of claims 1 to 9 in which said back sheet has moisture permeability.

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