JP6256944B2 - Absorbent articles - Google Patents

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 non-woven fabric piece containing a heat-bonding fiber and having a three-dimensional structure formed by bonding fibers in advance; a hydrophilic fiber; and a water-absorbing polymer particle, and mixing them. The absorbent article for absorbent articles formed by the above is described. Patent Document 4 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 2002-301105 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 in the form of a sheet. Therefore, the water-absorbing composite material is easily dropped during use of the absorbent article.

  In the techniques described in Patent Documents 3 and 4, since the water-absorbing polymer is held in the sheet, it is difficult for the polymer to fall off. However, an unpleasant graininess expressed by the water-absorbing polymer may be given to the user.

  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 first nonwoven fabric is disposed at a position closest to the surface sheet;
Between the back sheet and the first layer, a second layer in which a composite water-absorbing polymer is dispersed and disposed in a second nonwoven fabric made of thermoplastic fibers is disposed,
The first nonwoven fabric is a resin bond nonwoven fabric,
The composite water-absorbing polymer provides an absorbent article in which a fiber material is embedded in at least a part of the surface of the water-absorbing polymer.

  ADVANTAGE OF THE INVENTION According to this invention, the absorbent article which is excellent in spot absorptivity, has a quick water absorption speed, has little liquid remaining amount, and has a small liquid spreading area in the horizontal direction when viewed from the top sheet side 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) to 2 (c) are schematic views showing states of liquid permeation and diffusion in the absorber shown in FIG. FIG. 3 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 constituting the absorber may be made of a material having shape retaining property such as a sheet, for example, or formed by dispersing powder so as to have a predetermined thickness, It may be a layer having 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 be covered with a liquid-permeable sheet. 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 first layer 11 is composed of a first nonwoven fabric. As the first nonwoven fabric, a resin bond nonwoven fabric is used. 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 bond nonwoven fabric preferably has a thickness under a pressure of 245 Pa of 0.5 mm or more, particularly 1 mm or more. Moreover, it is preferable that it is 10 mm or less, especially 5 mm or less. For example, the resin bond nonwoven fabric preferably has a thickness of 0.5 mm to 10 mm, particularly 1 mm to 5 mm under a pressure of 245 Pa.

  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 the 2nd nonwoven fabric 15 by which the composite water absorbing polymer 14 was disperse | distributed. “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 | grains of the property polymer. By disposing the composite water-absorbing polymer 14 in the nonwoven fabric 15, the fiber material of the composite water-absorbing polymer 14 smoothly transfers the liquid that has passed through the first layer 11, and the liquid absorption by the water-absorbing polymer is prevented. It occurs efficiently. Accordingly, the amount of liquid that diffuses in the lateral direction is reduced, and the liquid diffusion area on the back sheet 21 side of the second layer 12 can be reduced. Further, due to the interaction between the fiber material of the composite water-absorbing polymer 14 and the constituent fibers of the second nonwoven fabric 15, the movement of the composite water-absorbing polymer 14 is restricted, and the dropout is effectively prevented. Is done. 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 means a material capable of retaining the gel to become water 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 products, saponified 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 before complexing 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 mass in a dry state, dissolving and removing the water-absorbing polymer, drying it, and measuring the mass of the fiber material alone. Specifically, first, the mass (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 mass of the composite water-absorbing polymer 14 and b is the mass of the fiber material in the composite water-absorbing polymer 14, the mass 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.

  In the nonwoven fabric 15, it is preferable that the composite water-absorbing polymers 14 are not joined. Moreover, it is preferable that the constituent fibers of the nonwoven fabric 15 and the composite water-absorbing polymer 14 are not joined.

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.

  The composite water-absorbing polymer 14 is dispersed and arranged in the second nonwoven fabric 15 and is held in the second nonwoven fabric 15. “Dispersion arrangement” means that the composite water-absorbing polymer 14 exists in the second nonwoven fabric 15 in a substantially uniform distribution. That is, when viewed along the planar direction of the second nonwoven fabric 15, the composite water-absorbing polymer 14 is substantially uniformly distributed, and also when viewed along the thickness direction of the second nonwoven fabric 15, It means that the water-absorbing polymer 14 is distributed almost uniformly. The second nonwoven fabric 15 is used to guide the liquid that has permeated from the first layer 11 to the composite water-absorbing polymer 14 via the constituent fibers of the second nonwoven fabric 15. The second nonwoven fabric 15 is used for holding the composite water-absorbing polymer 14 and preventing its movement.

  The composite water-absorbing polymer 14 may exist only inside the second nonwoven fabric 15 or may exist both inside and on the surface of the second nonwoven fabric 15. From the viewpoint of effectively preventing unintentional dropping of the composite water-absorbing polymer 14, the composite water-absorbing polymer 14 is preferably mainly present inside the second nonwoven fabric 15.

  The second nonwoven fabric 15 may use either natural fibers or synthetic fibers as its constituent fibers. 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 holding the composite water-absorbing polymer 14. In particular, the constituent fiber of the second nonwoven fabric 15 is a hydrophilic fiber from the viewpoint that the liquid that has permeated from the first layer 11 can be smoothly transferred to the composite water-absorbent polymer 14, and thereby the first non-woven fabric 15 is hydrophilic. It is preferable that the two nonwoven fabrics 15 have hydrophilicity. The hydrophilic fiber includes both a fiber made of a hydrophilic material and a hydrophobic material, and includes both fibers that have been subjected to a hydrophilic treatment and show hydrophilicity.

The basis weight of the second nonwoven fabric 15 is preferably 20 g / m ² or more, particularly preferably 30 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 nonwoven fabric 15 preferably has a basis weight of 20 g / m ² or more and 200 g / m ² or less, and more preferably 30 g / m ² or more and 100 g / m ² or less. From the same viewpoint, the second nonwoven fabric 15 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 10.0 mm or less, especially 7.0 mm or less. For example, the second nonwoven fabric 15 preferably has a thickness of 0.5 mm to 10.0 mm, particularly 1.0 mm to 7.0 mm, under a pressure of 245 Pa. By setting the basis weight and thickness of the second nonwoven fabric 15 in this way, the composite water-absorbing polymer 14 can be reliably held in the second nonwoven fabric 15 and has been transmitted from the first layer 11. The liquid can be efficiently guided to the composite water-absorbing polymer 14 through the constituent fibers of the second nonwoven fabric 15.

The 2nd nonwoven fabric 15 is comprised from 1 type, or 2 or more types of fiber. 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. As the thermoplastic resin, such as polyolefin resins such as polyethylene and polypropylene, vinyl, such as polyester resins, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl chloride, polystyrene, such as polyethylene terephthalate and polybutylene terephthalate Resin etc. are mentioned.

  When the second nonwoven fabric 15 is other than the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric, the fineness of the second nonwoven fabric 15 is preferably 1.0 dtex or more, and 1.5 dtex or more. Is more preferable. 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 using a fiber having a fineness in this range, the liquid that has permeated from the first layer 11 can be more efficiently guided to the composite water-absorbing polymer 14 via the constituent fibers of the second nonwoven fabric 15. .

  In particular, as the constituent fiber of the second nonwoven fabric 15, it is preferable to use an ultrafine fiber or an ultrafine fiber called a nanofiber having a smaller fiber diameter than this. By using nanofibers or ultrafine fibers, even if the absorber is sufficiently thin as 1.0 to 1.5 mm, the liquid that has permeated from the first layer 11 is passed through the constituent fibers of the second nonwoven fabric 15. In addition, the composite water-absorbing polymer 14 can be more efficiently guided. 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. Thus, when the 2nd nonwoven fabric 15 is a nanofiber nonwoven fabric or an ultrafine fiber nonwoven fabric, it is preferable that the fiber diameter of this 2nd nonwoven fabric 15 is 500 nm or more, and is 1000 nm or more. Is more preferable. 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 nanofiber nonwoven fabric or 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.

  As the second nonwoven fabric 15, 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.

  As the second nonwoven fabric 15, it is also possible to use a sheet formed by opening long fiber tows that are aligned in one direction. This long fiber preferably has crimps. By using the crimped long fibers, the composite water-absorbing polymer 14 can be stably held in the space formed by the crimped long fibers. As the 2nd nonwoven fabric 15 which consists of an open body of such a long fiber tow, the thing etc. of Unexamined-Japanese-Patent No. 2006-110329 etc. can be used, for example.

  In order to hold the composite water-absorbing polymer 14 in the second nonwoven fabric 15, for example, in the process of manufacturing the second nonwoven fabric 15, the composite water-absorbing polymer 14 is supplied, and while supplying the composite water-absorbing polymer 14, It is preferable to manufacture the nonwoven fabric 15. Alternatively, the second nonwoven fabric 15 is manufactured in advance, the composite water-absorbing polymer 14 is sprayed on one surface of the second nonwoven fabric 15, and then the second nonwoven fabric 15 is pressed from the sprayed surface side. A method of press-fitting the composite water-absorbing polymer 14 into the second nonwoven fabric 15 can also be employed. For the press, for example, a pair of calendar rolls can be used.

  In the case where the second nonwoven fabric 15 is made of a long-fiber tow spread body, the composite water-absorbing polymer 14 can be held in the spread body by the following method. First, a long fiber tow having a predetermined crimp rate is prepared. A web is obtained by opening the tow by a predetermined means while conveying the tow in a stretched state in the longitudinal direction. For the opening, for example, an air opening device using compressed air can be used. Since the long fibers have crimps, when the tension is applied, the long fibers are easily stretched in the longitudinal direction. The composite water-absorbing polymer 14 is spread on the opened web. At the time of spreading, the web is transferred onto a vacuum conveyor while the conveyance speed of the opened web is reduced. The web is untensioned on the vacuum conveyor. As a result, the stretched state of the web is released, and the long fibers return to the crimped state. Moreover, the thickness of the web is larger than that in the stretched state, and the embedded supportability of the composite water-absorbing polymer 14 is improved. Under this condition, the composite water-absorbing polymer 14 is dispersed. The long fibers in a crimped state have voids that can accommodate the composite water-absorbing polymer 14 between the fibers. The composite water-absorbing polymer 14 is buried and supported in the voids. Simultaneously with the application of the composite water-absorbing polymer 14, it is effective to suck the polymer 13 from the surface on the opposite side to the application surface of the polymer 13 to promote the embedded support of the polymer 13.

  The proportion of the second nonwoven fabric 15 in the entire second layer 12 is preferably 5% by mass or more, particularly preferably 10% by mass or more, and more preferably 95% by mass or less, and particularly preferably 90% by mass or less. For example, the proportion of the second nonwoven fabric 15 in the entire second layer 12 is preferably 5% by mass or more and 95% by mass or less, and more preferably 10% by mass or more and 90% by mass or less. By using the second nonwoven fabric 15 at this ratio, the liquid that has permeated from the first layer 11 can be efficiently guided to the composite water-absorbing polymer 14 via the constituent fibers of the second nonwoven fabric 15. . Further, the composite water-absorbing polymer 14 can be reliably held.

  On the other hand, the proportion of the composite water-absorbing polymer 14 in the entire second layer 12 is preferably 5% by mass or more, particularly preferably 10% by mass or more, and more preferably 95% by mass or less, particularly preferably 80% by mass or less. preferable. For example, the ratio of the composite water-absorbing polymer 14 in the entire second layer 12 is preferably 5% by mass or more and 10% by mass or less, and more preferably 95% by mass or more and 80% by mass or less. By using the composite water-absorbing polymer 14 at this ratio, the liquid absorption retention capacity of the absorber 10 can be sufficiently increased. In addition, it is possible to effectively prevent the composite water-absorbing polymer 14 from causing gel blocking in the second layer 12.

  In the absorbent body 10, the mass ratio between the first layer 11 and the second layer 12 is 100 parts by mass or more, particularly 300 parts by mass or more of the second layer 12 with respect to 100 parts by mass of the first layer 11. It is preferably 1000 parts by mass or less, more preferably 800 parts by mass or less. For example, it is preferable to use the second layer 12 in a ratio of 100 parts by mass or more and 1000 parts by mass or less with respect to the first layer 11 of 100 parts by mass, and the second layer 12 in a ratio of 300 parts by mass or more and 800 parts by mass or less. More preferably, it is used.

  As shown in FIG. 1, since the absorber 10 of this embodiment has a two-layer structure, 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 first nonwoven fabric that is a relatively hard material, that is, the first layer 11 made of a resin bond nonwoven fabric, the constituent fibers of the second nonwoven fabric 15 of the second layer 12, Since the fiber material of the composite water-absorbing polymer 14 is likely to be entangled and mechanical bonding force is likely to be generated, both of the layers 11 and 12 are not bonded to each other when the absorber 10 is deformed. There is an advantage that voids are hardly generated between the 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 spot absorbability is further improved.

  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 show a state in which the surfaces of the first layer 11 and the second layer of the absorbent body 10 are viewed from the top sheet 20 side. 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 non-woven fabric, that is, the first layer 11 made of the resin bond non-woven fabric has a property of high liquid permeability, so that the liquid L diffuses in the lateral direction of the first layer 11. Rather than in the thickness direction. 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 transmission / diffusion of the liquid L on the surface of the second layer 12 facing the first layer 11. 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. Accordingly, although the liquid L is diffused in the lateral direction, the liquid that has migrated from the first layer 11 to the second layer 12 is once absorbed and held by the composite water-absorbing polymer 14, so that the liquid L at this time There is no excessive diffusion in the direction. When the second nonwoven fabric 15 is sufficiently thin, the transfer of the liquid L due to the action of the fiber material in the composite water-absorbing polymer 14 becomes more conspicuous as the constituent fibers of the second nonwoven fabric 15 become thinner. Or it becomes more remarkable when it consists of an ultrafine fiber.

  In addition, since the composite water-absorbing polymer 14 has a large number of fiber materials densely on its surface, and a capillary force is generated due to this, a liquid as shown in FIG. L diffuses laterally. 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. .

  Since the absorbent article provided with the above absorbent body 10 is particularly excellent in spot absorbability, it is 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 first nonwoven fabric is disposed at a position closest to the surface sheet;
Between the back sheet and the first layer, a second layer in which a composite water-absorbing polymer is dispersed and disposed in a second nonwoven fabric made of thermoplastic fibers is disposed,
The first nonwoven fabric is a resin bond nonwoven fabric,
An absorbent article, wherein the composite water-absorbing polymer is constituted by embedding a fiber material in at least a part of the surface of the water-absorbing polymer.

<2>
The absorbent article according to <1>, wherein the fiber material is cellulose fiber.
<3>
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 or less, in the above <1> or <2> The absorbent article as described.
<4>
The absorbent article according to any one of <1> to <3>, wherein the length of the fiber material is shorter than the size of the absorbent polymer.
<5>
The absorbent article according to any one of <1> to <4>, wherein the fiber material has a size that passes through a 40-mesh sieve based on JISZ8801-1: 2006.
<6>
The second nonwoven fabric preferably has a basis weight of 20 g / m ² or more, particularly preferably 30 g / m ² or more, more preferably 200 g / m ² or less, and particularly preferably 100 g / m ² or less <1>. Thru | or <5> any one of the absorbent articles.

<7>
The thickness of the second nonwoven fabric 15 under a pressure of 245 Pa is preferably 0.5 mm or more, particularly 1.0 mm or more, and 10.0 mm or less, particularly 7.0 mm or less. The absorbent article according to any one of <1> to <6>.
<8>
When the second nonwoven fabric is other than the nanofiber nonwoven fabric or the ultrafine fiber nonwoven fabric, the fineness of the second nonwoven fabric is preferably 1.0 dtex or more, and more preferably 1.5 dtex or more. The absorbent article according to any one of <1> to <7>, preferably 15 dtex or less, and more preferably 10 dtex or less.
<9>
The absorbent article according to any one of <1> to <7>, wherein the second nonwoven fabric is a nanofiber nonwoven fabric or an ultrafine fiber nonwoven fabric produced by an electrospinning method.
<10>
The nanofiber is the absorbent article according to <9>, wherein the thickness of the nanofiber is 10 to 3000 nm, particularly 10 to 1000 nm, when the thickness is represented by a circle equivalent diameter.
<11>
The constituent fibers of the second nonwoven fabric preferably have 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 <9 > Or <10>.

<12>
The composite water-absorbing polymer is supplied in the manufacturing process of the second nonwoven fabric, and the second nonwoven fabric is produced while the composite water-absorbing polymer is supplied, so that the second nonwoven fabric holds the composite water-absorbing polymer. The absorbent article according to any one of <1> to <11>.
<13>
A second non-woven fabric is produced in advance, and the composite water-absorbing polymer is sprayed on one side of the second non-woven fabric, and then the second non-woven fabric is pressed from the side of the sprinkling surface. The absorbent article according to any one of <1> to <12>, wherein the composite water-absorbing polymer is held in the second nonwoven fabric by being press-fitted into the second nonwoven fabric.
<14>
The absorbent article according to any one of <1> to <13>, wherein the second nonwoven fabric has hydrophilicity.
<15>
The absorbent article according to any one of <1> to <14>, wherein the first layer and the second layer are located adjacent to each other, and both layers are in a non-bonded state.
<16>
The absorbent article according to any one of <1> to <15>, wherein the back sheet has moisture permeability.

<17>
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, and preferably 200 g / m ² or less, particularly preferably 100 g / m ² or less. The absorbent article according to any one of <16>.
<18>
Any one of the above <1> to <17>, 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.
<19>
The absorbent article according to any one of <1> to <18>, wherein a distance between fibers of the constituent fibers of the resin bond nonwoven fabric is smaller than a size of the composite water-absorbing polymer.
<20>
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, and preferably 15 dtex or less, more preferably 10 dtex or less. The absorbent article according to any one of 1> to <19>.
<21>
The absorbent article according to any one of <1> to <20>, wherein the resin-bonded nonwoven fabric is hydrophilized.

<22>
The absorbent article according to any one of <1> to <21>, wherein the first layer made of a resin-bonded nonwoven fabric does not contain a water-absorbing polymer or a composite water-absorbing polymer.
<23>
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 <22>, wherein the absorbent article is in a state of protruding from the water-absorbing polymer particles.
<24>
<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 <23> any one of the absorbent articles.
<25>
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. The absorbent article according to any one of> to <24>.
<26>
The absorbent article according to any one of <1> to <25>, 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.

<27>
The proportion of the second nonwoven fabric in the entire second layer is preferably 5% by mass or more, particularly preferably 10% by mass or more, more preferably 95% by mass or less, and particularly preferably 90% by mass or less. The absorbent article according to any one of> to <26>.
<28>
The ratio of the composite water-absorbing polymer in the entire second layer is preferably 5% by mass or more, particularly preferably 10% by mass or more, more preferably 95% by mass or less, and particularly preferably 80% by mass or less. The absorbent article according to any one of 1> to <27>.
<29>
In the absorber, the mass ratio between the first layer and the second layer is preferably 100 parts by mass or more, particularly 300 parts by mass or more, with respect to the first layer of 100 parts by mass, The absorbent article according to any one of <1> to <28>, further preferably 1000 parts by mass or less, particularly preferably 800 parts by mass or less.
<30>
The absorbent article according to any one of <1> to <29>, which is a sanitary napkin 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]
(1) Manufacture of the first layer 11 Resin bond nonwoven fabric obtained by thinly cutting a trade name “Traveron IJ180R” and basis weight 300 g / cm ² by Hakura Seiki Co., Ltd., trade name “Slicer A-70LP” 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 2nd nonwoven fabric 15 of the 2nd layer 12 The nonwoven fabric which consists of an ultrafine fiber of polypropylene (PP) was manufactured using the ultrafine fiber nonwoven fabric manufacturing apparatus 100 shown in FIG. 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. 3). 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 fiber F transported in the air stream was made of PP mesh and transported by a transport 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 15 was as shown in Table 1.

(3) 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 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%.

(4) Production of second layer 12 On one surface of the second nonwoven fabric 15 made of the ultrafine fiber obtained in (2) above, the composite water-absorbing polymer 14 obtained in (3) above has a basis weight of 200 g / m ^2. Scattered with. The second nonwoven fabric 15 was pressed with a pair of calender rolls, and the composite water-absorbing polymer 14 was pressed into the nonwoven fabric 15 to obtain the second layer 12. The basis weight of the obtained second layer 12 was as shown in Table 1.

(5) Manufacture of absorber 10 On the 2nd layer 12 obtained by the above (4), 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.

[Example 2]
In this example, KC Flock W-50S (fine cellulose fiber, 42 mesh pass 90% or more) was used instead of the fiber material used in the production of the composite water-absorbing polymer 14 in (3) of Example 1. . Except this, it carried out similarly to Example 1, and obtained the absorber 10.

Example 3
In this example, a second nonwoven fabric made of an air-through nonwoven fabric was used instead of the second nonwoven fabric made of the ultrafine fiber used in (2) of Example 1. This air-through non-woven fabric is produced by processing a 2.8 dtex × 51 mm core-sheath type composite fiber having a core made of polyethylene terephthalate and a sheath made of polyethylene into a fiber web, and supplying the fiber web to a web shaping device. It is manufactured. In the web shaping apparatus, hot air having a temperature of 130 ° C. and a wind speed of 47.5 m / second is supplied, and the above-described pedestal (MD-direction pitch: 8 mm, CD-direction pitch: 5 mm) having a large number of protrusions is provided on the pedestal. The fiber web was fixed. Next, hot air (temperature: 145 ° C., wind speed: 5 m / s) is blown onto the fiber web on the pedestal to shape the fiber web along the protrusions on the pedestal, and the fibers of each core-sheath structure are fused. Thus, a desired air-through nonwoven fabric was obtained. 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 10.

Example 4
In this example, instead of the second non-woven fabric made of the ultrafine fiber used in (2) of Example 1, a second non-woven fabric made of a tow spread of acetate long fiber was used, and the second layer 12 was Manufactured. The fiber diameter of the long fibers was 1.9 dtex, and the total number of tow fibers was 25,000. The tow was opened using an air opening device under elongation to obtain a spread web. Further, the web was wound through a spread web between a roll in which a large number of disks were incorporated at predetermined intervals around the axis and a smooth receiving roll. Thereafter, the web was adjusted to a width of 100 mm, transferred to a vacuum conveyor with the conveyance speed reduced, and the tension of the web on the vacuum conveyor was relaxed to develop crimps. As a result, the space between the long fibers was widened to make it easier for the composite water-absorbing polymer 14 to enter, and the web was thickened to improve the embedding supportability of the composite water-absorbing polymer 14. The composite water-absorbing polymer 14 was sprayed on the web to obtain a second layer 12 in which the composite water-absorbing polymer 14 was embedded and supported in the spread web. Except this, it carried out similarly to Example 1, and obtained the absorber 10.

[Comparative Example 1]
In this comparative example, the first layer 11 was not used. Moreover, instead of the 2nd nonwoven fabric 15 which consists of a thermoplastic fiber of the 2nd layer 12, the dry weight pulp sheet of the basic weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 2]
In this comparative example, the first layer 11 was not used. Further, the composite water-absorbing polymer 14 was not used, and a normal water-absorbing polymer (same as the water-absorbing polymer before complexing used in Example 1) was used instead. Furthermore, instead of the second nonwoven fabric 15 made of the thermoplastic fibers of the second layer 12, a dry pulp sheet having a basis weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 3]
In this comparative example, as the resin bond nonwoven fabric which is the first nonwoven fabric of the first layer 11, those having the basis weight shown in Table 1 were used. Moreover, instead of the 2nd nonwoven fabric 15 which consists of a thermoplastic fiber of the 2nd layer 12, the dry weight pulp sheet of the basic weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 4]
In this comparative example, as the resin bond nonwoven fabric which is the first nonwoven fabric of the first layer 11, those having the basis weight shown in Table 1 were used. Furthermore, instead of the second nonwoven fabric 15 made of the thermoplastic fibers of the second layer 12, a dry pulp sheet having a basis weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 5]
In this comparative example, the composite water-absorbing polymer 14 was not used, and 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 which is the 1st nonwoven fabric of the 1st layer 11, the thing of the basic weight shown in Table 1 was used. Furthermore, instead of the second nonwoven fabric 15 made of the thermoplastic fibers of the second layer 12, a dry pulp sheet having a basis weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 6]
In this comparative example, the composite water-absorbing polymer 14 was not used, and 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 which is the 1st nonwoven fabric of the 1st layer 11, the thing of the basic weight shown in Table 1 was used. Furthermore, instead of the second nonwoven fabric 15 made of the thermoplastic fibers of the second layer 12, a dry pulp sheet having a basis weight shown in Table 1 was used. Except this, it carried out similarly to Example 1, and obtained the absorber.

[Comparative Example 7]
In this comparative example, the composite water-absorbing polymer 14 was not used, and 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 which is the 1st 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 the absorber.

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

[Liquid diffusion area, absorption time, and remaining amount of liquid]
The liquid diffusion area on the surface of the first layer, the surface of the second layer, and the back surface of the second layer in the absorber 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 second layer in the absorber was measured using image software (Media Cybernetics, Inc. (Trade name “Image-Pro Plus” manufactured by the company).
Furthermore, the mass of the first layer was measured, and the amount of liquid remaining in the first layer was determined by subtracting the mass of the first layer before horse blood injection.
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 diffusion area of the liquid in the first layer was small. In each example, the diffusion area of the front surface and the back surface of the second layer is smaller than three times the diffusion area of the first layer (the diffusion area of the second layer surface <3 × the diffusion area of the first layer). A sense of security can be obtained. That is, in these examples, the spread area of the liquid in the lateral direction when viewed from the top sheet side is small, and the spot absorption that diffuses in the lower layer without diffusing the liquid in the upper layer is particularly excellent. I understand. In addition, it can be seen that each example has a short liquid absorption time and a small amount of liquid remaining in the first layer. In particular, Example 2 had the least amount of remaining liquid in the first layer. Furthermore, in Examples 1 and 2, it can be seen that these excellent results can be obtained even though the second layer is thinner than Examples 3 and 4.
In contrast, in Comparative Examples 1 and 2 in which the first layer made of the resin bonded nonwoven fabric was not used, it can be seen that it takes a long time to absorb the liquid. In Comparative Examples 3 to 6 in which a non-woven fabric is not used for the second layer and a dry pulp sheet is used instead, the diffusion area of the front and back liquids of the second layer is larger than three times the diffusion area of the first layer. I understand that. It can be seen that even in Comparative Example 7, which is different from Example 1 only in that the composite water-absorbing polymer is not used, the liquid diffusion area in the first layer is increased.

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

Claims (6)

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 first nonwoven fabric is disposed at a position closest to the surface sheet;
Between the back sheet and the first layer, a second layer in which a composite water-absorbing polymer is dispersed and disposed in a second nonwoven fabric made of thermoplastic fibers is disposed,
The first nonwoven fabric is a resin bond nonwoven fabric,
An absorbent article, wherein the composite water-absorbing polymer is constituted by embedding a fiber material in at least a part of the surface of the water-absorbing polymer.   The absorbent article according to claim 1, wherein the fiber material is cellulose fiber. The absorptive article according to claim 2 in which said cellulose fiber has a size which passes a 40-mesh sieve based on JISZ8801-1: 2006.   The absorptive article according to any one of claims 1 to 3 in which the 2nd nonwoven fabric has hydrophilicity.   The absorbent article according to any one of claims 1 to 4, wherein the first layer and the second 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 5 in which said back sheet has moisture permeability.

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