JP6646533B2 - Absorber and absorbent article - Google Patents

Description

  The present invention relates to an absorbent body and an absorbent article.

  2. Description of the Related Art In absorbent articles such as disposable diapers, the material and structure of each member have been improved to improve their functions and wearing feeling. Absorbers for use in absorbent articles have also been developed with the aim of making such improvements, and various types of absorbents with enhanced functionality have been proposed in accordance with use conditions and types of articles.

Patent Document 1 discloses an absorbent pad including a tufted area which is a low-density area which is not densified, and a channel which separates and surrounds the tufted area, wherein the tufted area and the channel are continuous. Is disclosed. The channel includes a storage area and a transport area, the storage area having a greater density than the tuft area, and the transport area having a greater density than the storage area. The transport areas are separated from each other and surrounded by storage areas. Thereby, the penetration ability is improved, and softness is imparted.
However, in the absorbent article disclosed in Patent Document 1, although the permeation ability is improved, the absorption rate of the ordinary water-absorbing polymer is reduced in the absorption by repeated excretion, which is still insufficient to expect high absorption performance. Met.

  The disposable diaper disclosed in Patent Document 2 includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-absorbing core interposed between these two sheets. And it has a front waist area, a rear waist area, and a crotch area located between these two areas, and absorbs along an imaginary line extending from the front waist area to the rear waist area via the crotch area. At least a part of the liquid core is divided. In such a disposable diaper, the liquid-absorbent core is disposed between the first fiber layer and the second fiber layer mainly containing ground pulp and containing 1% by mass or more and 10% by mass or less of superabsorbent polymer particles, and between the fiber layers. This is a laminate comprising a superabsorbent polymer particle and a particle layer occupying 5% to 50% of the mass of the liquid-absorbent core. The thickness of the first fiber layer is at least 1.5 times the thickness of the second fiber layer. Except for the first and second fiber layers and the particle layer on the side surface of the liquid-absorbent core at the divided part, the surface sheet is formed between the side surfaces of the liquid-absorbent core that are divided and face each other. , And abuts on the back sheet, and the front and back sheets are joined to each other at the contact portion. The body fluid is not only absorbed from the top surface of the liquid-absorbent core, but is also directly absorbed from the side surface of the liquid-absorbent core into the particle layer and the fiber layer located below the particle layer. Therefore, this diaper not only effectively utilizes the liquid absorbing ability of the particle layer, but also effectively utilizes the liquid absorbing ability of the fiber layer below the particle layer even when the particle layer forms a gel block. .

  The disposable diaper disclosed in Patent Literature 3 contains a water-absorbing polymer excellent in water-absorbing properties for artificial urine under load in an absorber. However, it has been difficult to achieve a high absorption rate because a plurality of grooves are not arranged in the absorber.

JP-A-64-45801 JP-A-11-216161 JP-A-11-60975

  An object of the present invention is to have a good absorption performance for a liquid (aqueous liquid or body fluid such as urine, menstrual blood or sweat) which is repeatedly released after long use, that is, a high absorption amount and a high absorption rate An object of the present invention is to provide an absorbent body and an absorbent article that can exhibit high absorption performance without reducing the absorption speed even in repeated absorption of the excreted liquid.

  The present invention relates to an absorber having pulp and a water-absorbing polymer, the absorber having a concave portion (hereinafter, also referred to as a groove) having a depth of 20% to 100% of the thickness of the absorber, The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] in the absorber is 1/3 or more and 1 / 0.01 or less, and the water-absorbing polymer has a water absorption of 30 g / g or more. Provided is an absorber having a liquid absorption of 50 g / g or less and a liquid absorption under a pressure of 2 kPa of 20 g / g or more and 40 g / g or less.

  The present invention also provides a liquid-permeable top sheet having a skin-contacting surface, a liquid-impermeable backsheet having a non-skin-contacting surface, and an absorber interposed between the two sheets. And an absorbent article using the absorber of the present invention for the absorber.

  Since the absorbent body and the absorbent article of the present invention use the water-absorbing polymer having excellent absorbency even under a load, the absorbent polymer is prevented from being crushed, and the grooves arranged in the absorbent body are closed. It is secured without peeling. For this reason, the high absorption amount and the high absorption rate are compatible, and the absorption rate is hardly reduced even in the absorption by repeated excretion, and has an excellent effect of exhibiting high absorption performance from the start of use to the end of use. .

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which showed the preferable one Embodiment of the absorber of this invention, FIG. (1) is the perspective view which showed the outline of the absorber, FIG. 2 is the schematic cross section which showed the detail of the absorber. It is. It is a top view of an absorber explaining uneven distribution of a water absorbing polymer. It is the perspective view which showed an example of the absorption process when the excreted liquid was supplied to the absorber. FIG. 2 is a developed plan view showing a preferred embodiment of the absorbent article of the present invention. FIG. 2 is a schematic sectional view showing another preferred embodiment of the absorbent article of the present invention. It is a schematic structure sectional view showing the measuring device which measures the amount of absorption under pressure. It is a manufacturing process figure showing the manufacturing method of the sample absorptive article. It is the schematic structure sectional drawing which showed the position of the groove | channel in an Example and a comparative example.

One preferred embodiment of the absorber according to the present invention will be described below with reference to FIG.
As shown in FIG. 1, the absorber 10 of the present invention has a pulp 21 and a water-absorbing polymer 22, and the mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] is 1/3. It is 1 / 0.01 or less, preferably 1 / 2.5 or more and 1 / 0.1 or less, more preferably 1/2 or more and 1 / 0.5 or less. The absorbent body 10 is, for example, one in which a water-absorbing polymer 22 is dispersed between pulp 21 formed by stacking and forming. Alternatively, the water-absorbing polymer 22 may be dispersed between layers of the pulp 21 formed by stacking. If the mass ratio is too low, the amount of pulp is too small to hold the water-absorbing polymer 22 in the pulp 21, and if the mass ratio is too high, the amount of the water-absorbing polymer 22 is too small. As a result, the liquid absorption becomes insufficient. Therefore, the above absorption amount was set in the above range.

  The amount of water absorbed by the water-absorbing polymer 22 is 30 g / g or more and 50 g / g or less, preferably 30 g / g or more and 45 g / g or less, in terms of physiological saline, in consideration of the liquid absorptivity of the product. It is preferably from 31 g / g to 40 g / g, particularly preferably from 32 g / g to 36 g / g. If the water absorption amount of the water-absorbing polymer 22 is too small, it becomes difficult to sufficiently absorb the liquid, and the absorption capacity of the absorber 10 is small and the liquid return amount is large. On the other hand, when the water absorption of the water-absorbing polymer 22 is too large (in other words, when the cross-linking of the water-absorbing polymer 22 is weak and the gel strength is low), in a general absorbent, the absorbent polymer absorbs water and gels. Since gel blocking is caused, the liquid permeability between the gels deteriorates, and the absorption performance of the absorber decreases. As shown in FIG. 1, in the absorbent body 10 having the concave portions (grooves 11), even if the water-absorbing polymer 22 causes gel blocking to some extent, the liquid permeability is secured without blocking the grooves 11 (liquid flow paths). You. However, if gel blocking occurs to an excessive extent, the absorption rate of the absorber 10 is slow, the amount of liquid returned is large, and the absorption capacity is small. Therefore, the water absorption amount of the water-absorbing polymer 22 was set in the above range.

In addition, the absorption amount of the excretory liquid (artificial urine or physiological saline as a simulated liquid in a test) under a predetermined pressure is 20 g / g or more and 40 g / g or less, preferably 20 g / g or more under a pressure of 2 kPa. It is 35 g / g or less, more preferably 21 g / g or more and 30 g / g or less, particularly preferably 22 g / g or more and 28 g / g or less. Note that the pressure value of 2 kPa is an example of an average pressure when the baby presses the absorber 10 when the baby wears the absorber 10.
As a case where the absorption amount of the water-absorbing polymer 22 under pressure is reduced, generally, (1) the crosslinking of the polymer is very strong and the gel strength is too high, and (2) the crosslinking of the polymer is very weak and the gel strength is low. May be too low. In the case of (1), the water-absorbing polymer itself is not easily crushed under pressure, but the absorption capacity of the water-absorbing polymer under pressure is reduced due to insufficient ability to absorb the liquid of the water-absorbing polymer. It will not be absorbed inside and will spread and leak. In the case of (2), the water-absorbing polymer is easily crushed under pressure, and when gel blocking is caused to an excessive extent, the absorption rate of the absorber 10 is slow, the amount of liquid returned is large, and the absorption capacity is small.
A water-absorbing polymer having a large amount of absorption under pressure generally has very strong (1) cross-linking of the polymer, and the water-absorbing polymer itself does not collapse under pressure but has a small water absorption. Alternatively, (2) the polymer may be weakly cross-linked, exhibit no elasticity when absorbing water, and be easily crushed under pressure. In the case of (1), since the ability of the water-absorbing polymer to absorb the liquid is insufficient, the liquid leaks without being absorbed into the absorber 10. In the case of (2), when the water-absorbing polymer causes gel blocking to an excessive degree under pressure, the absorption rate of the absorber 10 is slow, the liquid return amount is large, and the absorption capacity is small.
The water-absorbing polymer 22 in which the amount of the excreted liquid absorbed under pressure is set in the above range is moderately strong in cross-linking, so that the water-absorbing polymer 22 itself is not easily crushed. Therefore, under the situation where the liquid (for example, urine) is discharged, the load of the wearer does not collapse under the pressure applied to the absorber 10, so that the water-absorbing polymer 22 protrudes into the groove 11 described later and absorbs water. The groove 11 (the liquid passage) is suppressed from being blocked by the conductive polymer 22. Therefore, the liquid permeability in the groove 11 is ensured and maintained, so that the liquid flow in the groove becomes faster. That is, since the liquid can be rapidly diffused, the diffusion speed is increased, and the absorption time of the liquid is shortened. Moreover, liquid return hardly occurs.
Further, depending on the behavior of the wearer, the distribution situation, and the like, the water-absorbing polymer 22 may be unevenly distributed somewhere in the absorber 10 (for example, in the case of the absorber 10 shown in FIG. 2, the absorber block 12 in the center portion). Uneven distribution: Equivalent to around the crotch of the wearer.). In general, a water-absorbing polymer having a low water absorption under pressure tends to suffer from swelling inhibition at a high packing density (corresponding to an uneven distribution state) even under a constant load, resulting in a decrease in water absorption. However, in the absorbent body 10 having the concave portion, swelling inhibition can be reduced to some extent by the space of the concave portion (the groove 11).
Therefore, the lower limit of the absorption amount of the water-absorbing polymer 22 under a pressure of 2 kPa is set in the above range.
If the amount of the water-absorbing polymer 22 absorbed under pressure is too large, the water-absorbing polymer 22 swells beyond a certain extent, the recesses (grooves 11) are buried or closed, and the passage of the liquid during repeated excretion is reduced. Since there is a possibility that the absorption may not be ensured, the upper limit of the absorption amount under a pressure of 2 kPa is set in the above range.

  The thickness of the absorber 10 is 0.5 mm or more and 20 mm or less. Preferably it is 1 mm or more and 10 mm or less, more preferably 1.5 mm or more and 5 mm or less. If the thickness of the absorber 10 is too thin, it is difficult to secure a sufficient amount of absorption, and it is difficult to wear it for a long time. If it is too thick, the fit (body compatibility) of the absorber to the body decreases. Therefore, the thickness of the absorber 10 was set in the above range.

  The absorber 10 has a groove 11 on one surface side. The groove 11 has, for example, a plurality of vertical grooves 11A in a longitudinal direction (Y direction) of the absorber 10 and a plurality of lateral grooves 11B in a width direction (X direction) orthogonal to the longitudinal direction. The lateral grooves 11B are arranged, for example, by shifting the arrangement position in the longitudinal direction for each row in the longitudinal direction. The vertical groove 11A and the horizontal groove 11B are connected to form a continuous groove. The groove 11 may be arranged in various forms, for example, a part of the grooves 11 may be arranged in an oblique lattice shape or a curved shape.

  The depth D of the groove 11 is 20% or more and 100% or less of the thickness T of the absorber 10, preferably 25% or more and 95% or less, more preferably 30% or more and 90% or less, and further preferably 30% or less. % Or more and 85% or less. Although not shown, when the depth D is 100%, the absorber 10 is separated into a plurality of absorber blocks by the grooves 11. As shown in the figure, when the depth D is less than 100%, a plurality of absorber blocks 12 are divided at the side of the groove 11, and a part of the absorber 10 is left at the bottom of the groove 11. In this case, the plurality of absorber blocks 12 are connected by an absorber 10B located at the bottom of the groove 11. If the depth of the groove 11 is smaller than the above range, the absorption of the liquid supplied to the absorber 10 becomes insufficient. Therefore, the depth of the groove 11 is in the above range.

  The total area of the openings of the grooves 11 in plan view is 10% or more and 40% or less with respect to the surface area of the absorber 10 in plan view (the sum of the total surface areas of the separated blocks 12 and the total surface areas of the grooves 11). And preferably 15% or more and 35% or less, more preferably 20% or more and 30% or less. If the total area of the grooves 11 is less than 10%, the amount of liquid that can pass through the grooves 11 decreases, so that the diffusivity of the liquid decreases, and it becomes difficult to spread the liquid over a wide range of the absorber 10. On the other hand, if the total area of the grooves 11 is too large, the diffusivity of the liquid is increased, but the volume of the absorber 10 for storing the liquid is too small, and it becomes difficult to sufficiently absorb the liquid. In addition, the function as a liquid flow path is also reduced.

  The width of the groove 11 is 1 mm or more and 10 mm or less, preferably 2 mm or more and 8.5 mm or less, and more preferably 3 mm or more and 7 mm or less. If the width of the groove 11 is too wide, it will not have a function as a groove, and if it is too narrow, the liquid permeability will decrease and the range in which the liquid is diffused through the groove 11 will be narrow, and the absorption amount of the liquid will decrease, resulting in an absorber. The liquid will be returned to the surface.

  When the absorber 10 is provided at the bottom of the groove 11, the density of the absorber 10 at the bottom of the groove 11 is preferably lower than the density of the absorber 10 other than the bottom of the groove 11. As described above, since the density of the absorber 10 at the bottom of the groove 11 is lower than the density of the other absorbers 10, the liquid supplied into the groove 11 can easily spread inside the groove 11, and the absorption at the bottom of the groove 11 can be improved. It becomes easy to be absorbed by the body 10. When the density of the absorber 10 at the bottom of the groove 11 is equal to the density of the absorber 10 at the side wall of the groove 11, the liquid supplied into the groove 11 flows from the bottom and the side wall of the groove 11 into the absorber 10. Is absorbed by On the other hand, when the density of the absorber 10 at the bottom of the groove 11 is higher than the density of the other absorbers 10, the liquid supplied to the groove 11 is absorbed into the absorber 10 from the side wall of the groove 11, and And it is difficult to spread widely. For this reason, the liquid absorption amount decreases. Therefore, the density range was set as described above.

  The absorbent body 10 of the present invention has both a high absorption rate and a high absorption rate of a liquid by arranging a plurality of grooves 11 vertically and horizontally and using a water-absorbing polymer 22 having excellent absorbency even under a load. However, even in the absorption of the excreted liquid by repeated excretion, the absorption rate is hardly reduced, and an excellent effect of exhibiting high absorption performance from the start of use to the end of use is exhibited.

For example, an example of an absorption process in a case where the excreted liquid is supplied to the above-described absorber 10 will be described with reference to FIG. 3 which is a conceptual diagram.
As shown in FIG. 3A, an excretory liquid (for example, urine) 60 is supplied to the absorber 10. Then, as shown in FIG. 3 (2), the excretory liquid 60 quickly flows into the groove 11 of the absorber 10, and the flow path of the groove 11 is secured, so that the liquid 60 quickly spreads along the groove 11 and spreads in all directions. Go. At this time, it also diffuses into the absorber 10 at the bottom and the side wall of the groove 11. If the absorber block 12 has a higher density than the absorber 10B at the bottom of the groove 11, it is mainly diffused into the absorber 10B at the bottom of the groove 11. Then, as shown in FIG. 3 (3), the excretory liquid 60 spreads using the groove 11 as a flow path and diffuses into the absorber 10B at the bottom of the groove 11, and is eventually absorbed by the absorber block 12 by capillary force. The excreted liquid is stored in the absorber block 12 and fixed. Thus, in the absorber 10, high absorption performance and high absorption speed are realized.

Also, by using the above-described water-absorbing polymer 22, the liquid absorption amount of the absorber 10 is improved. Therefore, when the same absorption amount as the conventional product is used, the usage amount of the water-absorbing polymer 22 is reduced, This enables thinning. Therefore, there are also advantages such as reduction in thickness and size of the absorbent article using the absorber 10 of the present invention.
Furthermore, since the absorber 11 has the grooves 11 in the vertical and horizontal directions on one surface side, the degree of freedom with respect to the deformation of the absorber 10 is increased. For this reason, the body compatibility of the absorber 10 is enhanced, and liquid can be passed to the end of the absorber 10, so that the liquid absorption amount of the absorber 10 can be improved.

Hereinafter, the water absorbing polymer 22 will be described in detail.
The water-absorbing polymer 22 is a polymer particle having a water-absorbing property, and the production method is not limited. The shape is not particularly limited, and may be spherical, massive, grape-like, irregular, porous, powdery, or fibrous. The average particle size of the water-absorbing polymer 22 is 100 μm or more and 1000 μm or less, preferably 150 μm or more and 650 μm or less, for the purpose of suppressing dropout from the product, suppression of movement, and suppression of deterioration in use (roughness). Preferably it is 200 μm or more and 500 μm or less. The amount of water absorbed by the water-absorbing polymer 22 and the amount of absorption under pressure are as described above.

  As an example, the water-absorbing polymer 22 polymerizes at least one selected from the following monomers. Crosslinking is performed as necessary. The polymerization method is not particularly limited, and various generally known methods of a water-absorbing polymer such as a reversed-phase suspension polymerization method and an aqueous solution polymerization method can be employed. Thereafter, the polymer is subjected to operations such as pulverization and classification as necessary to adjust the polymer to a desired average particle size, and if necessary, treated with inorganic fine particles.

  The monomer used when producing the water-absorbing polymer 22 is a water-soluble monomer having a polymerizable unsaturated group. Specifically, olefinically unsaturated carboxylic acids or salts thereof, olefinically unsaturated carboxylic esters, olefinically unsaturated sulfonic acids or salts thereof, olefinically unsaturated phosphoric acids or salts thereof, olefinically unsaturated phosphates And vinyl monomers having a polymerizable unsaturated group such as olefinically unsaturated amines, olefinically unsaturated ammonium salts, and olefinically unsaturated amides.

  Examples of the olefinically unsaturated carboxylic acid or a salt thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid, and alkali metal salts and ammonium salts thereof.

  Examples of the olefinically unsaturated carboxylic acid ester include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, and phenoxy polyethylene glycol (meth). Acrylate and the like.

  Examples of olefinically unsaturated sulfonic acids or salts thereof include vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, 2- (meth) acrylamido-2-methylpropane sulfonic acid, 2- (meth) acryloyl ethane sulfonic acid, (Meth) acryloylpropanesulfonic acid or a salt thereof.

  Examples of the olefinically unsaturated phosphoric acid or a salt thereof include (meth) acryloyl (poly) oxyethylene phosphate and a salt thereof.

  Examples of the olefinically unsaturated amine include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (Meth) acrylamide and the like.

  Examples of the olefinically unsaturated ammonium salt include the quaternary ammonium salts of the above-mentioned olefinically unsaturated amine.

  Examples of the olefinically unsaturated amide include (meth) acrylamide, methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) And (meth) acrylamide derivatives such as acrylamide, and vinylmethylacetamide.

  Specific examples of the other monomers include nonionic hydrophilic group-containing unsaturated monomers such as vinylpyridine, N-vinylpyrrolidone, N-acryloylpiperidine, N-acryloylpyrrolidine, and N-vinylacetamide.

  In this specification, (meth) acrylate means acrylate or methacrylate, (meth) acrylamide means acrylamide or methacrylamide, and (meth) acryloyl means acryloyl or methacryloyl.

  Among these monomers, olefinically unsaturated carboxylic acids or salts thereof are preferable, acrylic acid, methacrylic acid, alkali metal salts, alkaline earth metal salts or ammonium salts thereof are more preferable, and acrylic acid and alkali metal acrylate salts are preferable. (Lithium salt, sodium salt, potassium salt, etc.) and ammonium acrylate are more preferred.

  Next, as a preferred embodiment of the absorbent article according to the present invention, a disposable diaper (hereinafter, referred to as a diaper) 50 to which the above-described absorber 10 is applied will be described below with reference to FIG. In FIG. 4, the topsheet 16 at the central portion in the longitudinal direction Y of the diaper 50 is notched.

As shown in FIG. 4, the diaper 50 has a shape in which a central portion in the longitudinal direction Y corresponding to a crotch portion as a whole is constricted. The top sheet 16 and the back sheet 17 extend outward from the left and right side edges and the front and rear ends of the absorber 10, respectively. The size of the top sheet 16 in the width direction X is smaller than the size of the back sheet 17 in the width direction X.
The diaper 50 is a deployable diaper, and has a pair of fastening tapes FT attached to both side edges at one end in the longitudinal direction Y. At the other end, a landing tape LT is mounted on the back sheet 17.
The topsheet 16 is preferably not joined to the groove 11 of the absorber 10 from the viewpoint that the water-absorbing polymer 22 easily swells sufficiently.

  The diaper 50 is provided with three-dimensional gathers that can rise above the side edges of the absorber 10 in the width direction X. That is, on each side of the diaper 50 in the longitudinal direction Y, a three-dimensional gather sheet material (side sheet) 18 having a gather elastic member 56 is arranged to form a three-dimensional gather. Further, on both sides of the diaper 50 in the longitudinal direction Y, one or more (two in this drawing) leg elastic members 58, 58 for a pair of left and right for leg gathers are arranged to form a leg gather. I have. The leg elastic members 58 for leg gathers are arranged substantially linearly in a stretched state on the leg flaps extending outward on both side edges in the longitudinal direction Y of the absorber 10. In this case, the longitudinal direction Y of the diaper 50 and the longitudinal direction Y of the absorber 10 are the same.

  The sheet material 18 for three-dimensional gathers has one or a plurality of (two in the drawing) gather elastic members 56 fixed to one side edge in an extended state. The sheet material 18 is joined to the topsheet 16 along the longitudinal direction Y of the diaper 50 at a position outside the left and right side edges of the absorbent body 10 in the width direction X, and the joined portion is formed by a three-dimensional gather. It is the rising base end. The sheet material 18 extends outward from the base end of the diaper 50 in the width direction X of the diaper 50, and is joined to the back sheet 17 at the extended portion. The sheet material 18 is joined to the topsheet 16 at the front and rear ends of the diaper 50 in the longitudinal direction Y.

As the sheet material 18 for three-dimensional gathers, a liquid-impermeable or water-repellent and moisture-permeable material is preferably used. Examples of the sheet material 18 include a liquid-impermeable or water-repellent porous resin film, a liquid-impermeable or water-repellent nonwoven fabric, and a laminate of the porous resin film and the nonwoven fabric. Examples of the nonwoven fabric include a thermal bond nonwoven fabric, a spunbond nonwoven fabric, a spunbond-meltblown-spunbond (SMS) nonwoven fabric, a spunbond-meltblown-meltblown-spunbond (SMMS) nonwoven fabric, and the like. The basis weight of the sheet material 18 is preferably 5 g / m ² or more and 30 g / m ² or less, and more preferably 10 g / m ² or more and 20 g / m ² or less.

  As the topsheet 16, various types of diapers conventionally used in this type of diaper can be used, and there is no limitation as long as the topsheet 16 can transmit a liquid such as urine. It is preferable to use a soft material. For example, a woven or nonwoven fabric made of synthetic fibers or natural fibers, a porous sheet, and the like can be given. As an example, a nonwoven fabric made of a natural fiber such as cotton or a nonwoven fabric made of various synthetic fibers subjected to a hydrophilic treatment can be used. For example, after a core-sheath structure type (including side-by-side type) composite fiber using polypropylene or polyester as the core component and polyethylene as the sheath component is formed into a web by carding, a non-woven fabric (which is then opened at a predetermined location) by an air-through method. (A hole treatment may be performed). From the viewpoint of high liquid permeability (dry feeling), an aperture sheet made of polyolefin such as low-density polyethylene can also be preferably used.

As the back sheet 17, various kinds of diapers conventionally used in this type of diaper can be used, and a liquid-impermeable or water-repellent and moisture-permeable one is preferably used. Specifically, in order to obtain sufficient water vapor permeability, a synthetic resin film such as polyethylene in which fine powder including a filler such as calcium carbonate is dispersed is stretched, and a porous film having fine holes is used. preferable. For example, a material that can be used as the above-described sheet material 18 for forming three-dimensional gathers can be used. Further, the width of the back sheet 17 is set to be substantially the same as the width of the absorber 10 and is arranged on the non-skin contact surface side of the absorber 10. A laminate of a nonwoven fabric and a film may be arranged as a sheet constituting the outer shape of the diaper.
The non-skin contact surface is a surface that faces the clothes side (the side opposite to the wearer's skin side) when the diaper is worn. In the following, the term “skin contact surface” may be used, but the skin contact surface is a surface that is turned toward the wearer's skin when the diaper is worn.

  Examples of the side sheet include a nonwoven fabric, a film sheet, and paper. From the viewpoint of leakproofing, the side sheet is preferably formed of a liquid-impermeable or hardly permeable hydrophobic nonwoven fabric, a leakproof film sheet, or the like. The number of the above sheets may be one, or two or more may be combined with a functional sheet or the like.

Further, in addition to the top sheet 16, the absorber 10, the back sheet 17, and the side sheets, members may be present as appropriate according to uses and functions.
Further, as shown in FIG. 5, an intermediate sheet 19 (mount) may be arranged between the top sheet 16 and the absorber 10.
Examples of the intermediate sheet 19 include those having a function of drawing in and diffusing and retaining the excreted liquid, those that reduce the amount of liquid returned, those that suppress leakage of the water-absorbing polymer, those that suppress collapse of the absorber, and the like. Used.
Examples of the sheet having such performance include a nonwoven fabric or film containing fibers having hydrophilicity or fibers treated with a hydrophilic oil agent or the like, or a porous body. Examples of fibers for the intermediate sheet include (1) natural cellulose fibers such as non-wood pulp such as wood pulp such as softwood kraft pulp and hardwood kraft pulp and cotton pulp and straw pulp, and (2) regenerated cellulose fibers such as rayon and cupra. (3) hydrophilic synthetic fibers such as polyvinyl alcohol fiber and polyacrylonitrile fiber, and (4) synthetic fibers such as polyethylene terephthalate (PET) fiber, polyethylene (PE) fiber, polypropylene (PP) fiber and polyester fiber as surfactants. And the like can be used alone or in combination of two or more.
As the intermediate sheet 19, for example, paper such as tissue paper, woven fabric, non-woven fabric, knitted fabric, parchment, papyrus, pulp pile, or the like can be used. Examples of the nonwoven fabric include a chemical bond nonwoven fabric, a thermal bonded nonwoven fabric, an airlaid nonwoven fabric, a spunlace nonwoven fabric, a spunbonded nonwoven fabric, a melt blown nonwoven fabric, a needle punched nonwoven fabric, a stitch bonded nonwoven fabric, and the like.
These sheets may be in a single-layer state, or may have a multilayer structure in which a plurality of layers are stacked to form one sheet. In addition, a three-dimensional network is formed in the structure by means of a sheet having elasticity (for example, a nonwoven fabric (elastic nonwoven fabric) containing fibers containing an elastic resin as constituent fibers, a film containing an elastic resin (elastic film), or foaming). Or an elastic porous body made of an elastic resin.
The basis weight of the intermediate sheet 19 is preferably 5 g / m ² or more and 80 g / m ² or less, and particularly preferably 10 g / m ² or more and 30 g / m ² or less. Further, the thickness is preferably 0.05 mm or more and 5.0 mm or less, and particularly preferably 0.1 mm or more and 3.0 mm or less.
The intermediate sheet 19 may be provided only between the top sheet 16 and the absorber 10 or may be provided between the absorber 10 and the back sheet 17. It may be arranged so that it may be.

  The diaper 50 as the absorbent article of the present invention achieves both high absorption and high absorption speed by the action of the absorber 10, and uses a stretchable sheet as a base sheet (not shown) of the absorber 10. Due to this, it is deformed according to the complexly undulating skin surface, conforms to the human body to contact with the surface without gaps, and deforms according to the movement of the wearer's body, maintaining the state of contact with the skin surface It has the ability to follow movements. The diaper 50 has the versatility that it can be used in the same manner as a normal unfolded diaper.

  The absorbent article is not limited to the above-described embodiment, but can be applied as another embodiment to this type of absorbent article, for example, a disposable diaper, an incontinence pad, an incontinence liner, and the like. It is also effective not only for urine but also for menstrual blood, orimono, loose stool and the like. In addition to the top sheet 16, the absorber 10, the back sheet 17, and the side sheets, members may be appropriately incorporated in accordance with the use or function. The materials of the topsheet 16, the absorber 10, and the backsheet 17 of the above-described embodiment, the conditions in the manufacturing method, and the dimensions of the product are not particularly limited, and various commonly used materials can be used.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples.

Example 1
First, a method for calculating the average particle size of the water-absorbing polymer will be described below.
As a method for calculating the average particle diameter, 100 g of the water-absorbing polymer is classified using a sieve according to JIS Z-8801-1982, and the average particle diameter is determined from the mass fraction of each fraction.

Next, a method for measuring the water absorption of the water-absorbing polymer will be described below.
The amount of water absorption was measured at room temperature (20 ± 5 ° C.) by swelling 1.00 g of the water-absorbent polymer with 150 mL of room temperature (20 ± 5 ° C.) physiological saline (0.9% NaCl aqueous solution, manufactured by Otsuka Pharmaceutical) for 30 minutes. After that, the mixture is placed in a 250-mesh nonwoven fabric bag, dehydrated with a centrifuge at 143 G for 10 minutes, and the total mass (total mass) after the dehydration is measured. Then, according to the following equation (1), the amount of physiological saline retained after centrifugal dehydration is measured, and this value is defined as the water absorption.

ここで、不織布袋液残り量＝（遠心脱水後の不織布袋質量）−（不織布袋質量）である。

Here, the remaining amount of liquid in the nonwoven fabric bag = (mass of nonwoven fabric bag after centrifugal dehydration) − (mass of nonwoven fabric bag).

Next, with reference to FIG. 6, a measuring device for performing the method of measuring the amount of absorption under pressure will be described.
As shown in FIG. 6A, a column 210 is prepared in which a mesh 213 (250 mesh) is stuck to a lower end opening 212 of a cylinder 211 (30 mm in inner diameter) which is set up vertically. 0.500 g of the water-absorbing polymer 22 (particles) is put therein so as to have a uniform thickness. Next, a weight 221 (a weight to which a pressure of 2.0 kPa can be applied) slightly smaller than the outer diameter of 30 mm is placed on the water-absorbing polymer 22.
Into a 100 mL beaker 230, 100 mL of physiological saline 231 (0.9% by mass sodium chloride aqueous solution) at room temperature (20 ± 5 ° C.) is poured. Then, the column 210 is immersed in a physiological saline solution 231 so that the mesh 213 is not attached to the bottom of the beaker 230, and left for 1 hour in this state.
Thereafter, the column 210 is taken out of the beaker 130 and drained for 15 minutes while the weight 221 is placed on the water-absorbing polymer 22, as shown in FIG. The temperature of this test atmosphere is room temperature (20 ± 5 ° C.).
Then, the absorption amount under pressure is calculated according to the following equation (2).

Next, a synthesis example of the water-absorbing polymer will be described below.
As Synthesis Example 1, synthesis of water-absorbing polymer I was performed as follows.
In Synthesis Example 1, first, as a dispersant, a polyoxy resin manufactured by Kao Corporation was used as a dispersant in a SUS304 5 L reaction vessel (using an anchor blade) equipped with a stirrer, a reflux condenser, a monomer dropping port, a nitrogen gas inlet pipe, and a thermometer. 0.11% [mass of acrylic acid] of sodium ethylene lauryl ether sulfate (trade name: Emal 20C) was charged, and 1600 mL of cyclohexane was added. The mixture was stirred under a nitrogen atmosphere and heated to an internal temperature of 77 ° C.

  On the other hand, 80% acrylic acid and ion-exchanged water manufactured by Toagosei Co., Ltd. were charged into a 2 L three-necked flask, and a 48% aqueous solution of caustic soda manufactured by Asahi Glass Co., Ltd. was dropped while cooling with ice. 1054 g of an aqueous solution of sodium acid (72% neutralized product, concentration: about 48%) was obtained. To this aqueous monomer solution was added a solution prepared by dissolving 0.18 g of N-acylated sodium glutamate (trade name: Amisoft GS-11F) manufactured by Ajinomoto Co., Inc. in 3 g of ion-exchanged water. Aqueous monomer solution A), 264 g (hereinafter, monomer aqueous solution B), and 528 g (hereinafter, monomer aqueous solution C) were divided into three parts.

Then, 0.12 g of 2,2′-azobis (2-amidinopropane) dihydrochloride (trade name: V-50) manufactured by Wako Pure Chemical Industries, Ltd., 0.20 g of polyethylene glycol (PEG6000) manufactured by Kao Corporation, ion 14 g of exchanged water was mixed and dissolved to prepare an aqueous solution of the initiator (A). In addition, 0.49 g of sodium persulfate manufactured by Wako Pure Chemical Industries, Ltd. was dissolved in 10 g of ion-exchanged water to prepare an aqueous solution of the initiator (B). Further, an aqueous solution of titanium citrate (50% citric acid and an aqueous solution of titanyl sulfate were mixed at a mass ratio of 20/27) was prepared.
7.2 g of aqueous solution of initiator (A) is added to aqueous solution A of monomer to prepare monomer A, and 7.2 g of aqueous solution of initiator (A) and 1.5 g of aqueous solution of titanium citrate are added to aqueous solution of monomer B to prepare monomer B Then, 10.5 g of the initiator (B) aqueous solution and 3 g of the titanium citrate aqueous solution were added to the monomer aqueous solution C to prepare a monomer C.

  Using a microtube pump, monomer A, monomer B, and monomer C, which had been allowed to stand for 5 minutes or more, were sequentially dropped from the monomer dropping port of the 5 L reaction vessel over about 60 minutes to polymerize. After the dropping of the monomer is completed, azeotropic dehydration is performed using a dehydration tube to adjust the water content of the water-absorbing polymer (hydrogel) to 60%, and ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.) A solution prepared by dissolving 0.33 g of Nanadenacol EX-810 in 10 g of water was added. After that, azeotropic dehydration was further performed, and after cooling, cyclohexane was removed, followed by drying under reduced pressure to obtain a water-absorbing polymer. After removing coarse particles with a sieve having an opening of 850 microns, 0.5 part of Aerosil 200 manufactured by Nippon Aerosil Co., Ltd. was dry-blended with 100 parts of the polymer particles to obtain a water-absorbing polymer I.

As Synthesis Example 2, synthesis of water-absorbing polymer II was performed as follows.
In Synthesis Example 2, 0.33 g of ethylene glycol diglycidyl ether (trade name: Denacol EX-810) manufactured by Nagase Kasei Kogyo Co., Ltd. was changed to 0.18 g as the crosslinking agent in the above Synthesis Example 1, and the water-absorbing polymer was changed to 0.18 g. Obtained. To this water-absorbing polymer, 1% (based on the weight of the water-absorbing polymer) of a quaternary ammonium salt (trade name: Cotamine 86W) manufactured by Kao Corporation was added after dilution with water and dried. After removing coarse particles with a sieve having an aperture of 850 microns, 100 parts of the polymer particles were dry-blended with 0.5 part of Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd.) to obtain the water-absorbing polymer II. Obtained.

As Synthesis Example 3, synthesis of water-absorbing polymer III was performed as follows.
In Synthesis Example 3, the same operation as in Synthesis Example 2 was performed except that 0.18 g of ethylene glycol diglycidyl ether (trade name: Denacol EX-810) manufactured by Nagase Kasei Kogyo Co., Ltd. was changed to 0.25 g as a crosslinking agent. Was carried out to obtain a water absorbent polymer III.

As Synthesis Example 4, synthesis of water-absorbing polymer IV was performed as follows.
As a dispersant, a sodium polyoxyethylene lauryl ether sulfate (manufactured by NOF Corporation) was used as a dispersant in a SUS304 5 L reaction vessel (using an anchor blade) equipped with a stirrer, a reflux condenser, a monomer dropping port, a nitrogen gas inlet pipe, and a thermometer. 0.06% [mass weight of acrylic acid] of trade name and 0.04% [mass weight of acrylic acid] of sodium stearoylmethyltaurine (trade name of Nikkor SMT) manufactured by Nikko Chemicals Co., Ltd. were charged with 1600 mL of heptane. added. The mixture was stirred under a nitrogen atmosphere and heated to an internal temperature of 88 ° C.

  On the other hand, 80% acrylic acid and ion-exchanged water manufactured by Toagosei Co., Ltd. were charged into a 2 L three-necked flask, and a 48% aqueous solution of caustic soda manufactured by Asahi Glass Co., Ltd. was dropped while cooling with ice. 1054 g of an aqueous solution of sodium acid (72% neutralized product, concentration: about 48%) was obtained. A solution obtained by dissolving 0.25 g of N-acylated sodium glutamate (trade name: Amisoft GS-11F) in 3 g of ion-exchanged water was added to the aqueous monomer solution, and the mixture was stirred for a while. Aqueous monomer solution D), 264 g (hereinafter, monomer aqueous solution E), and 528 g (hereinafter, monomer aqueous solution F) were divided into three parts.

Next, 0.041 g of 2,2'-azobis (2-amidinopropane) dihydrochloride (trade name: V-50) manufactured by Wako Pure Chemical Industries, Ltd., 0.20 g of polyethylene glycol (PEG6000) manufactured by Kao Corporation, ion 9 g of exchanged water was mixed and dissolved to prepare an initiator (C) aqueous solution. In addition, 0.49 g of sodium persulfate manufactured by Wako Pure Chemical Industries, Ltd. was dissolved in 10 g of ion-exchanged water to prepare an aqueous solution of the initiator (D). Further, an aqueous solution of titanium citrate (50% citric acid and an aqueous solution of titanyl sulfate mixed at a mass ratio of 20/54) was prepared.
2.3 g of aqueous solution of initiator (C) is added to aqueous solution D of monomer to prepare monomer A, and 6.9 g of aqueous solution of initiator (C) and 1.5 g of aqueous solution of titanium citrate are added to aqueous solution of monomer E to prepare monomer E Then, 10.5 g of the initiator (D) aqueous solution and 3 g of the titanium citrate aqueous solution were added to the monomer aqueous solution F to prepare the monomer F.

  Using a microtube pump, monomer D, monomer E, and monomer F, which had been allowed to stand for 5 minutes or more, were sequentially dropped from the monomer dropping port of the 5 L reaction vessel over about 60 minutes to carry out polymerization. After the polymerization is completed, azeotropic dehydration is performed using a dehydration tube, the water content of the water-absorbing polymer (hydrogel) is adjusted to 60%, and ethylene glycol diglycidyl ether (trade name) manufactured by Nagase Kasei Kogyo Co., Ltd. as a crosslinking agent A solution prepared by dissolving 0.12 g of Denacol EX-810) in 10 g of water was added. Thereafter, azeotropic dehydration was further performed, and after cooling, heptane was removed, followed by drying under reduced pressure to obtain a water-absorbing polymer. After removing coarse particles with a sieve having an opening of 850 μm, 0.5 part of Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd.) is dry-blended with 100 parts of the polymer particles to obtain a water absorbent polymer IV. Was.

  Table 1 shows the average particle size, water absorption and absorption under pressure of 2 kPa of each of the water-absorbing polymers I, II, III and IV in Synthesis Examples 1 to 4 described above.

As Example 1, an absorbent article provided with an absorber having the shape shown in FIG. 7 was produced as follows.
As shown in FIG. 7A, the water-absorbing polymer 22 was prepared using the water-absorbing polymer III obtained in Synthesis Example 3, and a laminate 23 of the pulp sheet 21S and the water-absorbing polymer 22 (with a basis weight of 50 g / m ² ). Three layers of the water-absorbing polymer 22 were sprayed at a basis weight of 100 g / m ^{2 on} each of the four layers of the pulp sheet 21S. As shown in FIG. 7 (2), the laminate 23 was cut so as to have a horizontal width h2 = 30 mm and a vertical width h1 = 50 mm to produce an absorber block 24. A tissue paper having a basis weight of 16 g / m ² coated with a hot melt agent (not shown) is used as the base sheet 13, and the cut absorber block 24 is cut on the base sheet 13 with a horizontal gap e = 5 mm and a vertical gap d. = 5 mm, and arranged and fixed in 3 rows × 7 columns.
Next, a tissue paper (not shown) having a basis weight of 16 g / m ² coated with a hot melt agent was placed on the upper side (skin contact surface side) of each absorber block 24, and pressed with a mangle.
The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] was 1 / 1.5. The thickness of the absorber was 3 mm.
Although not shown, the absorbent obtained by pressing was arranged between the top sheet and the back sheet to obtain an absorbent article. For the surface sheet that is the skin contacting surface, use the Kao Corporation product name Merize surface material. For the liquid-impermeable back sheet, use the Kao Corporation product name Merize back sheet. Was.

Examples 2, 3, 4 and Comparative Example
As Example 2 , an absorbent article was obtained in the same manner as in Example 1, except that the water absorbing polymer III was changed to the water absorbing polymer IV obtained in Synthesis Example 4.

As Example 3, in Example 1, after the absorber blocks 24 cut in the above-described manner were arranged in a matrix of 3 × 7 on the base sheet 13 and fixed, the grooves (width 5 mm) between the absorber blocks 24 were removed. as basis weight is 50 g / ^{m 2,} connecting between the absorber blocks 24 arranged one use the basis weight of 50 g / ^{m 2} pulp sheet 21S (width 5mm) in example 1 and the groove, A pulp continuous layer having a thickness of one pulp sheet was arranged on the base sheet 13 side.
Next, a tissue paper (not shown) having a basis weight of 16 g / m ² coated with a hot melt agent was placed on the upper side (skin contact surface side) of each absorber block 24, and pressed with a mangle. The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] was 1 / 1.4. The thickness of the absorber was 3 mm, and the depth of the recess was 1.5 mm (50%).
Hereinafter, the same operation as in Example 1 was performed to obtain an absorbent article. When the pressed absorber was arranged between the top sheet and the back sheet, a pulp continuous layer was arranged on the back sheet side.

  As Example 4, when the pressed absorber was placed between the top sheet and the back sheet in the above-described Example 3, the pulp continuous layer was arranged on the top sheet side upside down.

As Comparative Example 1, an absorbent article was obtained in the same manner as in Example 1, except that the water absorbing polymer III was changed to the water absorbing polymer I obtained in Synthesis Example 1.
The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] in the absorber was 1 / 1.5, and the thickness of the absorber was 3 mm.
As Comparative Example 2, an absorbent article was obtained by performing the same operation as in Example 1 except that the water absorbing polymer III in Example 1 was changed to the water absorbing polymer II obtained in Synthesis Example 2.
The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] in the absorber was 1 / 1.5, and the thickness of the absorber was 3 mm.
As Comparative Example 3, in Example 1, with basis weight of each layer 80 g / m ² water-absorbing polymer III between the laminate (basis weight 50 g / m ² pulp sheets 4 layers of a pulp and water-absorbing polymer prepared (Three-layer spray) was cut into a width of 100 mm and a length of 375 mm to obtain an absorbent article. Incidentally, the basis weight of the water-absorbing polymer was reduced by the extent that the area of the absorber was larger than that in Example 1, and the amount of the water-absorbing polymer used was the same as in Example 1.
The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] in the absorber was 1 / 1.2, and the thickness of the absorber was 3 mm.
As Comparative Example 4, Comparative Example 1, with basis weight of each layer 90 g / m ² water-absorbing polymer I between the laminate (basis weight 50 g / m ² pulp sheets 4 layers of a pulp and water-absorbing polymer prepared (Three-layer spray) was cut into a width of 100 mm and a length of 375 mm to obtain an absorbent article. The area of the absorber was larger than that of Comparative Example 1, and the basis weight of the water-absorbing polymer was reduced, and the amount of the water-absorbing polymer used was about 1.13 times that of Example 1.
The mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] in the absorber was 1 / 1.4, and the thickness of the absorber was 3 mm.

Next, a method of measuring the absorption rate and the liquid return amount of the absorbent article will be described. As an example, the case of a baby diaper (M size) will be described.
An acrylic cylinder having an inner diameter of 35 mm was placed 150 mm from the abdominal edge in the longitudinal direction of the absorbent article and 35 mm in the center in the width direction, and 40 g of colored artificial urine was applied while applying a load of 2.0 kPa to the entire absorbent article. The liquid was injected while maintaining the liquid at a height of 10 mm. In addition, an acrylic plate large enough to cover the entire absorbent article is provided at the bottom of the cylinder. At this time, the time required for absorption was measured (absorption time 1). The shorter the absorption time, the better the performance. Ten minutes after the start of absorption, 40 g was injected again and the absorption time was measured (absorption time 2). This operation was repeated twice more, a total of 160 g of physiological saline was injected, and the absorption time was measured (absorption times 3, 4). The temperature of the test atmosphere was room temperature (20 ± 5 ° C.), and the temperature of artificial urine was room temperature (20 ± 5 ° C.).
Ten minutes after the completion of the injection, a filter paper No. A stack of 10 sheets of 4A (100 mm × 100 mm, mass measurement W1) was placed on the absorbent article centering on the injection point.
A pressure of 3.5 kPa was applied through an acrylic plate having a thickness of 5 mm and 100 mm x 100 mm, and after 2 minutes, the weight of the filter paper was measured (W2), and the liquid return amount was calculated by the following equation.

  Liquid return amount (g) = mass of filter paper after pressurization (W2)-mass of first filter paper (W1)

The measured absorption rate and liquid return amount were evaluated in three steps according to the following evaluation criteria.
The case where the absorption time was less than 30 seconds was rated as ○, the case where the absorption time was 30 seconds or more and less than 60 seconds was rated as Δ, and the case where the absorption time was 60 seconds or more was rated as x. In addition, the case where the liquid return amount was less than 1.0 g was rated as ○, the case where it was 1.0 g or more and less than 1.5 g was rated as Δ, and the case where it was 1.5 g or more was rated as x.

Next, a method for evaluating the absorption amount of the absorbent article will be described below.
The prepared absorbent article is placed on an acrylic plate inclined at 20 degrees (the belly edge is on the lower side), and an acrylic plate and a weight are placed thereon, and a load of 2.0 kPa is applied to the entire absorbent article. Was. In this state, the artificial urine colored at a position 200 mm from the upper end of the absorbent article is repeatedly injected at regular intervals and at regular intervals, and the injection amount until leaking from the lower end of the absorber is measured. Compared. The temperature of the test atmosphere was room temperature (20 ± 5 ° C.), and the artificial urine used was room temperature (20 ± 5 ° C.).
The relative value when the absorption capacity of Comparative Example 4 was set to 1.0 was calculated using the following formula.

  Absorption capacity (relative value) = (absorption capacity of sample) / (absorption capacity of comparative example 4)

  Table 2 shows the composition of the artificial urine.

  Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated by the above evaluation method. The results are shown in Tables 3 to 5. In addition, about "groove position" in Tables 3-5, it showed by the schematic structure sectional drawing of the absorbent article 50 in FIG. The reference numerals shown in the drawing are the same as the reference numerals of the respective components described above.

  As shown in Tables 3 to 5, in Examples 1 to 4, the absorption time of the liquid was less than 30 seconds in the first time, and the absorption time was less than 60 seconds in the second to fourth absorptions. Was. On the other hand, in the comparative example, comparative example 1 obtained almost the same evaluation result as the example with respect to the absorption time, but the comparative example 2 using the water-absorbing polymer having a low absorption amount under pressure and the groove. In Comparative Examples 3 and 4 using absorbers that were not used, the absorption time for the second and subsequent times took 60 seconds or more, and the absorption time was prolonged. As a result, it was found that the liquid absorption performance of the example was maintained high from the start of use to the end of repeated absorption.

  As described above, the water-absorbing polymer 22 used in the absorbent body 10 of the present invention is, for example, assuming that the urine of the baby is about 40 cc per one time, the first excretion (urination), the second time, the third time, and the fourth time. Even in the case of excretion, since the water-absorbing polymer 22 does not easily swell even when absorbing the excretion liquid (urine), the state of the groove 11 at the time of the first excretion is maintained. For this reason, the groove 11 is not closed by the water-absorbing polymer 22, and the liquid permeability of the groove 11 is ensured. As a result, the absorption rate of the excreted liquid is increased.

  Further, in Examples 1 to 4, the liquid return amount was less than 1.5 g and Comparative Example 1 using a water-absorbing polymer having a small water absorption, Comparative Example 2 using a water-absorbing polymer having a low absorption under pressure, and In Comparative Example 3 having no groove in the absorber, the liquid return amount was 1.5 g or more. As a result, it was found that the liquid return amount of each example was small.

Thus, in the case of the conventional water-absorbing polymer having a low absorption amount under pressure as in Comparative Example 2, the liquid can be passed through the groove 11 in the first urination. However, in the second and subsequent urination, the load of the wearer is applied to the water-absorbing polymer swollen in the first urination, the water-absorbing polymer is crushed and protrudes into the groove 11, and in the worst case, the groove 11 Since the liquid is blocked, it is difficult to pass the liquid through the groove 11. For this reason, in the second and subsequent discharges, the liquid discharged in the groove 11 becomes difficult to flow or does not flow, so that the liquid cannot be sufficiently diffused and the liquid return amount increases.
On the other hand, in the absorbent polymer used in each of the examples, since the water-absorbing polymer hardly swells for the second and subsequent discharges, the drainage liquid is diffused throughout the absorber without closing the groove 11. , The amount of liquid returned can be less than 1.5 g.

Further, the absorption capacities of Examples 1 to 4 were all 1.0 compared to Comparative Example 4 in which the amount of the water-absorbing polymer used was 1.13 times larger than that of Example 1, and the same as Comparative Example 4. It was found to be the absorption capacity. That is, it was found that each example had a sufficient absorption capacity.
As described above, since each of the examples has a sufficient absorption capacity, in each of the examples, the liquid return amount is as small as less than 1.5 g, while in Comparative Example 1, the absorption capacity is 0.8 g. And the liquid return amount increases. Further, in Comparative Example 3, the same amount of the water-absorbing polymer III as in Example 1 was used, but since it did not have a groove, the absorption capacity as an absorber was as low as 0.8, and the liquid return amount was small. More.

  As described above, according to the absorbent body 10 and the absorbent article 50 using the absorbent body 10 of the present invention, a high absorption amount and a high absorption rate can be achieved at the same time in the repeated absorption of the drainage liquid by long-term use. In addition, the liquid return amount is small, and high absorption performance can be exhibited.

DESCRIPTION OF SYMBOLS 10 Absorber 11 Groove 12 Absorber block 16 Top sheet 17 Back sheet 19 Intermediate sheet 21 Pulp 22 Water absorbing polymer 50 Absorbent article (diaper)

Claims (5)

An absorbent body having a liquid-permeable top sheet disposed on the skin contact surface side, a back sheet disposed on the non-skin contact surface side, and pulp and a water-absorbing polymer disposed on both of the sheets. With
Before Symbol absorber has a plurality of recesses extending in a direction intersecting the recesses of said plurality of, optionally interconnected, form a flow channel of excretion solution in the absorber,
A mass ratio represented by [mass of pulp] / [mass of water-absorbing polymer] in the absorber is 1/3 or more and 1 / 0.01 or less;
The water-absorbing polymer has a water absorption of 30 g / g or more and 36 g / g or less, and a liquid absorption under a pressure of 2 kPa of 20 g / g or more and 30 g / g or less ,
A thickness of the absorber is 0.5 mm or more and 20 mm or less, the recess has a depth of 20% or more and 100% or less of a thickness of the absorber, and a width of the recess is 1 mm or more and 10 mm or less; The total area of the openings of the concave portions as viewed in plan with respect to the surface area of the absorber as viewed from 10% to 40%.
Absorbent articles.   2. The absorbent article according to claim 1, wherein the total area of the openings of the recesses in plan view is 10% or more and 30% or less with respect to the surface area of the absorber in plan view.   The absorbent article according to claim 1, wherein the recess has a depth of 100% of a thickness of the absorber.   The absorbent article according to any one of claims 1 to 3, wherein a concave portion exists on the side of the top sheet of the absorber.   The absorbent article according to any one of claims 1 to 4, wherein a concave portion exists on the back sheet side of the absorber.

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