JP6515245B2 - Absorbent body and absorbent article - Google Patents

Description

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

  In absorbent articles such as disposable diapers, the material and structure of each member have been improved, and the function and feeling of wearing have been improved. With regard to the absorbent used for the absorbent article, such improvements have been intended and developed, and various proposals have been made to enhance the functionality according to the use situation and the type of the article.

Patent Document 1 discloses an absorbent pad including a tuft area, which is a low density area not densified, and a channel which mutually separates and surrounds the tuft area, and the tuft area and the channel are continuous. Is disclosed. The channel comprises 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 also separated and surrounded by storage areas. This improves penetration ability and imparts softness.
However, in the absorbent article disclosed in Patent Document 1, although the permeation ability is improved, in the case of ordinary water-absorbing polymers, the absorption rate is reduced in absorption due to repeated excretion, and it 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-impervious back sheet, and a liquid-absorbent core interposed between the both sheets. Then, suction is provided along a virtual line having a front waist area, a back waist area, and a crotch area located between these two areas and extending from the front waist area to the back waist area via the crotch area. At least a portion of the liquid core is divided. In such a disposable diaper, the absorbent core is disposed between the first fiber layer and the second fiber layer containing 1% by mass or more and 10% by mass or less of superabsorbent polymer particles mainly with pulverized pulp. It is a layered product which consists of a particle layer which occupies 5% or more and 50% or less of the absorbent core mass mainly with super absorbent polymer particles. The thickness of the first fiber layer is 1.5 or more times the thickness of the second fiber layer. The first and second fiber layers and the particle layer are on the side of the absorbent core at the divided portion, and the surface sheet is the side between the sides of the absorbent core which is divided and opposed to each other. The front and back sheets are in contact with each other at their contact points. The body fluid is not only absorbed from the top surface of the absorbent core, but also absorbed directly from the side of the absorbent core to the particle layer and the fiber layer located below the particle layer. Therefore, this diaper not only makes effective use of the liquid absorbing capacity of the particle layer, but also makes effective use of the liquid absorbing capacity of the fiber layer below the particle layer even when the particle layer forms a gel block. .

  The disposable diaper disclosed in Patent Document 3 contains a water absorbing polymer excellent in water absorbency to artificial urine under a load in an absorbent body. However, it has been difficult to achieve fast absorption rates, as multiple grooves are not placed in the absorber.

JP-A-64-45801 Japanese Patent Application Laid-Open No. 11-216161 Japanese Patent Application Laid-Open No. 11-60975

  The object of the present invention is to have good absorption performance for a liquid (aqueous liquid or body fluid such as urine, menstrual blood or sweat) repeatedly released by long-term use, that is, high absorption amount and high absorption rate And providing an absorbent and an absorbent article capable of exhibiting high absorption performance without reducing the absorption speed even in repeated absorption of the excretory fluid.

  The present invention is an absorber having a pulp and a water absorbing polymer, and is an absorber having a recess (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 amount of 30 g / g or more Provided is an absorber having a capacity of 50 g / g or less and an absorbed amount of liquid under a pressure of 2 kPa of 20 g / g or more and 40 g / g or less.

  Further, according to the present invention, a liquid-permeable top sheet in which the skin contact surface side is disposed, a liquid-impermeable back sheet in which the non-skin contact surface side is disposed, and an absorber disposed between both sheets And an absorbent article using the above-mentioned absorbent according to the present invention.

  The absorbent body and the absorbent article of the present invention are prevented from collapsing the absorbent polymer by using a water-absorbing polymer excellent in absorbability even under load, and the grooves arranged in the absorbent are clogged. Secured without falling apart. For this reason, the high absorption amount and the high absorption rate are compatible, and the absorption rate is difficult to decrease even in repeated absorption, and the excellent action and effect of exhibiting high absorption performance from the start of use to the end of use are exhibited. .

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which showed one preferable embodiment of the absorber of this invention, (1) The figure which is a perspective view which showed the outline of an absorber, (2) schematic sectional drawing which showed the detail of an absorber It is. It is a top view of the absorber explaining the uneven distribution of a water absorbing polymer. It is the perspective view which showed an example of the absorption process when the drainage liquid is supplied to an absorber. It is the unfolded top view which showed one preferable embodiment of the absorbent article of this invention. It is a schematic structure sectional view showing another preferred embodiment of the absorbent article of the present invention. It is a schematic structure sectional view showing a measuring device which measures absorption under pressure. It is a manufacturing-process figure which showed the manufacturing method of the absorbent article of a sample. It is the schematic structure sectional view which showed the position of the groove in an example and a comparative example.

One preferred embodiment of the absorbent according to the present invention will be described below with reference to FIG.
As shown in FIG. 1, the absorbent body 10 of the present invention has a pulp 21 and a water absorbing polymer 22, and the mass ratio of [mass of pulp] / [mass of water absorbing polymer] is 1/3. More than 1 / 0.01 or less, Preferably it is 1 / 2.5 or more and 1 / 0.1 or less, More preferably, it is 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 pulps 21 formed by stacking. Alternatively, the water absorbing polymer 22 may be dispersed between the layers of the pulp 21 formed by stacking. When the above mass ratio is too low, the amount of pulp is too small to hold the water absorbing polymer 22 in the pulp 21, and when the above mass ratio is too high, the amount of the water absorbing polymer 22 becomes too small. So the amount of liquid absorbed will be insufficient. Therefore, the said absorption amount was made into the said range.

  Further, the water absorption amount of the water absorbing polymer 22 is 30 g / g or more and 50 g / g or less, preferably 30 g / g or more and preferably 45 g / g or less, in consideration of the absorbability of the liquid of the product. Preferably, it is 31 g / g or more and 40 g / g or less, and particularly preferably 32 g / g or more and 36 g / g or less. When the water absorption amount of the water absorbing polymer 22 is too small, it is difficult to absorb the liquid sufficiently, 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 amount of the water absorbing polymer 22 is too large (in other words, when the crosslinking of the water absorbing polymer 22 is weak and the gel strength is low), the absorbent polymer absorbs water and gels in a general absorber. In order to cause gel blocking, the liquid permeability between the gels is deteriorated, and the absorption performance of the absorber is reduced. As shown in FIG. 1, in the absorbent body 10 having the concave portion (groove 11), even if the water absorbing polymer 22 causes gel blocking to some extent, liquid permeability is ensured without blocking the groove 11 (flow path of liquid) Ru. However, if gel blocking occurs to a large extent, the absorption rate of the absorber 10 is slow, the amount of liquid reversion is large, and the absorption capacity is also small. Therefore, the water absorption amount of the water absorbing polymer 22 is in the above range.

In addition, the absorption of the excrement fluid (test is artificial urine or physiological saline as a simulated fluid) under predetermined pressure is 20 g / g or more and 40 g / g or less under pressure of 2 kPa, preferably 20 g / g or more. It is 35 g / g or less, more preferably 21 g / g or more and 30 g / g or less, and particularly preferably 22 g / g or more and 28 g / g or less. In addition, 2 kPa of pressurization value is an example of an average pressure when the baby pressurizes the absorber 10 at the time of wear of the absorber 10.
In general, (1) when 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 as the case where the amount of absorption of the water-absorbing polymer 22 under pressure is small. It may be too low. In the case of (1), although the water absorbing polymer itself is difficult to be crushed under pressure, the ability of the water absorbing polymer to absorb the liquid is insufficient, so the amount of absorption under pressure decreases, and the liquid It will not be absorbed while it will spread and leak. In the case of (2), the water-absorbing polymer is easily crushed under pressure, and if gel blocking is caused to a large extent, the absorption speed of the absorber 10 is slow, the liquid return amount is large, and the absorption capacity is reduced.
In general, the crosslinkability of the (1) polymer is very strong, and the water absorbing polymer itself does not collapse under pressure, but the water absorption amount is small. Alternatively, (2) the crosslinkability of the polymer may be weak, it may not exhibit elasticity at the time of water absorption, and the water absorbent polymer itself may be easily crushed under pressure. In the case of (1), the liquid is not absorbed into the absorbent body 10 but leaks because the ability of the water-absorbent polymer to absorb the liquid is insufficient. In the case of (2), when the water-absorbing polymer causes gel blocking over pressure under pressure, the absorption rate of the absorber 10 is slow, the liquid return amount is large, and the absorption capacity is reduced.
The water absorbing polymer 22 in which the amount of absorption of the solution under pressure is set to the above range is suitably strong in crosslinking, so the water absorbing polymer 22 itself is unlikely to be crushed. Therefore, under the condition where the liquid (for example, urine) is discharged, the load of the wearer does not collapse under the pressure applied to the absorbent body 10, so the water absorbing polymer 22 protrudes inside the groove 11 described later. It is suppressed that the groove | channel 11 is closed by the polymer 22 and the groove | channel 11 (passage of a liquid) is ensured. Therefore, since the liquid permeability in the groove 11 is secured and maintained, the liquid flow in the groove becomes faster. That is, since the liquid can be diffused quickly, the diffusion speed is increased and the absorption time of the liquid is shortened. In addition, liquid return hardly occurs.
Furthermore, the water absorbing polymer 22 may be unevenly distributed somewhere in the absorber 10 depending on the behavior of the wearer, the distribution condition, etc. (For example, in the case of the absorber 10 shown in FIG. Uneven distribution: Corresponds to the wearer's crotch area.). In general, a water-absorbing polymer having a low water absorption under pressure tends to suffer from swelling inhibition when the packing density (corresponding to the uneven distribution state) is high even under a constant load, and the water absorption tends to decrease. However, in the absorber 10 having the recess, the swelling inhibition can be alleviated to some extent by the space of the recess (groove 11).
Therefore, the lower limit of the amount of absorption of the water-absorbent polymer 22 under pressure of 2 kPa is set to the above-mentioned range.
In addition, when the absorption of the above-mentioned water-absorbent polymer 22 under pressure is too large, the water-absorbent polymer 22 swells to a large extent, and the recess (groove 11) becomes buried or clogged, and the passage of liquid The upper limit of the absorption amount under pressure of 2 kPa is set to the above-mentioned range because there is a possibility that it will not be secured.

  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. When the thickness of the absorbent body 10 is too thin, it is difficult to secure a sufficient amount of absorption, and wearing for a long time becomes difficult, and when it is too thick, the fit (body adaptability) of the absorbent body to the body decreases. Therefore, the thickness of the absorber 10 was made into the said range.

  The absorber 10 has a groove 11 on one side. The groove 11 has, for example, a plurality of longitudinal grooves 11A in the longitudinal direction (Y direction) of the absorber 10, and a plurality of lateral grooves 11B in the width direction (X direction) orthogonal to the longitudinal direction. The lateral grooves 11B are arranged, for example, at different positions in the longitudinal direction for each row in the longitudinal direction. The longitudinal grooves 11A and the lateral grooves 11B are connected to form continuous grooves. In addition, it is possible to employ | adopt various forms of arrangement | positioning forms of the groove | channel 11, for example, one part may be arrange | positioned in the diagonal grid | lattice form, and curvilinear form may be sufficient as it.

  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, further preferably 30 % 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 groove 11. As shown in the drawing, when the depth D is less than 100%, a plurality of absorber blocks 12 are separated on 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 the absorber 10B present at the bottom of the groove 11. When the depth of the groove 11 is shallower 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.

  In addition, 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 total surface area of the separated blocks 12 and the total surface area of the grooves 11). Preferably they are 15% or more and 35% or less, More preferably, they are 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 flow through the grooves 11 decreases, so 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, when the total area of the grooves 11 is too large, the diffusibility of the liquid is enhanced, but the volume of the absorber 10 for storing and storing the liquid is too small, and it becomes difficult to absorb the liquid sufficiently. In addition, the function as a liquid flow path also decreases.

  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. When the width of the groove 11 is too wide, it does not have a function as a groove, and when it is too narrow, the liquid permeability is reduced, the range in which the liquid is diffused through the groove 11 becomes narrow, and the absorption amount of liquid decreases. It will be returned to the surface.

  When the absorber 10 is 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, the density of the absorber 10 at the bottom of the groove 11 is made lower than the density of the absorber 10 other than that, the liquid supplied into the groove 11 easily spreads in the groove 11, and the absorption at the bottom of the groove 11 is absorbed. It becomes easy to be absorbed by the body 10. When the density of the absorber 10 at the bottom of the groove 11 and the density of the absorber 10 at the side wall of the groove 11 are the same, the liquid supplied into the groove 11 flows from the bottom of the groove 11 and the side wall to the inside of the absorber 10 Absorbed by On the other hand, when the density of the absorber 10 at the bottom of the groove 11 is made higher than the density of the other absorbers 10, the liquid supplied to the groove 11 is absorbed from the side wall portion of the groove 11 into the absorber 10. It becomes difficult to spread widely. For this reason, the amount of absorption of the liquid decreases. Therefore, it was set as the above-mentioned density range.

  The absorbent body 10 of the present invention has both grooves 11 arranged longitudinally and transversely, and by using the water-absorbing polymer 22 excellent in absorbability even under load, it is possible to achieve both high absorption of liquid and high absorption speed. In addition, the absorption rate of the excretory fluid due to repeated excretion is difficult to reduce, and the excellent action and effect of exhibiting high absorption performance from the start of use to the end of use can be achieved.

For example, an example of the absorption process when the drainage liquid is supplied to the above-described absorber 10 will be described with reference to FIG. 3 which is a conceptual view.
As shown in FIG. 3 (1), a drainage solution (for example, urine) 60 is supplied to the absorber 10. Then, as shown in FIG. 3 (2), the drainage solution 60 quickly flows into the groove 11 of the absorber 10 and the flow passage of the groove 11 is secured. Go. At this time, it also diffuses to the absorber 10 at the bottom of the groove 11 and the side wall. When the absorber block 12 has a higher density than the absorber 10B at the bottom of the groove 11, it is mainly diffused to the absorber 10B at the bottom of the groove 11. Then, as shown in FIG. 3 (3), the drainage solution 60 spreads through the groove 11 as a flow path, and is diffused into the absorber 10B at the bottom of the groove 11 and is eventually absorbed by the absorber block 12 by capillary force. The excrement fluid is stored and immobilized in the absorber block 12. Thus, in the absorber 10, high absorption performance and high absorption speed are realized.

Moreover, since the liquid absorption amount of the absorber 10 is improved by using the water absorbing polymer 22 described above, the amount of the water absorbing polymer 22 used is reduced when the absorption amount is the same as that of the conventional product. Thinning is possible. Therefore, there is also an advantage such as thinning and downsizing of an absorbent article using the absorbent body 10 of the present invention.
Furthermore, since the grooves 11 are provided longitudinally and transversely on one surface side of the absorber 10, the degree of freedom for deformation of the absorber 10 is enhanced. As a result, the body compatibility of the absorber 10 is enhanced, and liquid can be passed to the end of the absorber 10, so that the amount of liquid absorbed by the absorber 10 can be improved.

Hereinafter, the water absorbing polymer 22 will be described in detail.
The water absorbent polymer 22 is a polymer particle having water absorbency, and the production method is not limited. The shape thereof may be spherical, massive, grape-like, irregularly-shaped, porous, powdery or fibrous regardless of the shape. The average particle diameter 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, in order to suppress the dropout from the product and the movement and the feeling of use deterioration (grained feeling). Preferably they are 200 micrometers or more and 500 micrometers or less. Further, the water absorption amount of the water absorbing polymer 22 and the absorption amount under pressure are as described above.

  As an example, the water absorbing polymer 22 polymerizes one or more selected from the following monomers. In addition, it crosslinks as needed. The polymerization method is not particularly limited, and various methods of generally known water absorbent polymers such as reverse phase suspension polymerization method and aqueous solution polymerization method can be adopted. Thereafter, the polymer is subjected to operations such as pulverization and classification as necessary, adjusted to a desired average particle diameter, and obtained as required by inorganic fine particle treatment.

  The monomer used in producing the water-absorbent polymer 22 is a water-soluble monomer having a polymerizable unsaturated group. Specifically, an olefinically unsaturated carboxylic acid or salt thereof, an olefinically unsaturated carboxylic acid ester, an olefinically unsaturated sulfonic acid or salt thereof, an olefinically unsaturated phosphoric acid or salt thereof, an olefinically unsaturated phosphate ester Examples are vinyl monomers having a polymerizable unsaturated group such as an olefinically unsaturated amine, an olefinically unsaturated ammonium salt, and an olefinically unsaturated amide.

  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, alkali metal salts thereof, ammonium salts and the like.

  As an olefinic unsaturated carboxylic acid ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, phenoxy polyethylene glycol (meth) An acrylate etc. are mentioned.

  As olefinic unsaturated sulfonic acid or a salt thereof, vinylsulfonic acid, allylsulfonic acid, styrenesulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- Examples include (meth) acryloyl propane sulfonic acid or a salt thereof.

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

  As the olefinically unsaturated amine, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (Meth) acrylamide etc. are mentioned.

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

  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-acryloyl piperidine, N-acryloyl pyrrolidine, N-vinyl acetamide and the like.

  In the present 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 thereof, alkaline earth metal salts or ammonium salts are more preferable, and acrylic acid, acrylic acid alkali metal salts (Lithium salt, sodium salt, potassium salt and the like) and ammonium acrylate are more preferable.

  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 absorbent body 10 is applied will be described below with reference to FIG. In addition, in FIG. 4, the surface sheet 16 of the center part of the longitudinal direction Y of the diaper 50 is notched.

As shown in FIG. 4, the diaper 50 has a shape in which the central portion in the longitudinal direction Y corresponding to the crotch 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 dimension of the front sheet 16 in the width direction X is smaller than the dimension of the back sheet 17 in the width direction X.
The diaper 50 is a spreadable diaper, and at one end in the longitudinal direction Y, a pair of fastening tapes FT is attached to the side edges thereof. At the other end, a landing tape LT is attached on the back sheet 17.
It is preferable that the surface sheet 16 is not joined to the grooves 11 of the absorbent body 10 from the viewpoint that the water-absorbent polymer 22 easily swells sufficiently.

  The diaper 50 includes a solid gather that can rise above the side edge of the absorbent body 10 in the width direction X. That is, the sheet material (side sheet) 18 for solid gathers which has the gathers elastic member 56 is distribute | arranged to each of the both sides of the longitudinal direction Y in the diaper 50, and the solid gathers are comprised. Further, on both sides of the longitudinal direction Y in the diaper 50, one pair or one pair (two in the drawing) of leg elastic members 58 and 58 for the leg gathers are disposed to constitute the leg gathers. There is. The leg elastic members 58 for the leg gathers are arranged in a substantially linear shape in an extended state in the outwardly extending leg flaps of the both side edges in the longitudinal direction Y of the absorbent body 10. In this case, the longitudinal direction Y in the diaper 50 and the longitudinal direction Y in the absorber 10 are in the same direction.

  The sheet member 18 for three-dimensional gathers has one or a plurality of gather elastic members 56 (two each in the drawing) fixed to one side edge thereof in an extended state. The sheet material 18 is joined to the surface sheet 16 along the longitudinal direction Y of the diaper 50 at a position on the outer side in the width direction X than the left and right side edges of the absorber 10, and the junction is a solid gather It is a rising base end. The sheet material 18 extends outward in the width direction X of the diaper 50 from the rising base end, and is joined to the back sheet 17 at the extension. The sheet material 18 is joined on the top sheet 16 at front and rear end portions in the longitudinal direction Y of the diaper 50.

As the sheet material 18 for the three-dimensional gathers, one that is liquid impermeable or water repellent and moisture permeable 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 non-woven fabric, or a laminate of the porous resin film and the non-woven fabric. Examples of the non-woven fabric include thermal bond non-woven fabric, spun bond non-woven fabric, spun bond-melt blown-spun bond (SMS) non-woven fabric, spun bond-melt blown-melt blown-spun bond (SMMS) non-woven 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 top sheet 16, various kinds of conventionally used ones in this type of diaper can be used, and there is no limitation as long as it can permeate liquid such as urine, and it is liquid permeable and to the skin It is preferable to be made of soft material. For example, woven or non-woven fabrics made of synthetic fibers or natural fibers, porous sheets and the like can be mentioned. As an example, non-woven fabric made of natural fibers such as cotton or non-woven fabric made of various synthetic fibers subjected to hydrophilization treatment can be used. For example, core-sheath type (including side-by-side type) composite fibers using polypropylene or polyester as the core component and polyethylene as the sheath component are formed into a web by carding, and then nonwoven fabric is formed by air through method (It may be given a hole treatment). In addition, a perforated sheet made of a polyolefin such as low density polyethylene can be preferably used from the point of liquid permeability (dry feeling).

As the back sheet 17, various kinds of conventionally used ones in this type of diaper can be used, and one having liquid impermeability or water repellency and moisture permeability is preferably used. Specifically, in order to obtain sufficient water vapor permeability, a film made of a synthetic resin such as polyethylene in which fine powder consisting of a filler such as calcium carbonate is dispersed is stretched to use a porous film having fine pores. preferable. For example, those usable as the above-described sheet material 18 for forming a three-dimensional gather can be used. Further, the width of the back sheet 17 is made approximately the same as the width of the absorber 10 and disposed on the non-skin contact surface side of the absorber 10, and further non-woven fabric or the like on the non-skin contact surface side of the back sheet 17. A laminate of a non-woven fabric and a film or the like may be arranged as a sheet constituting the outer shape of the diaper.
The non-skin contact surface is a surface directed to the clothes side (opposite to the skin of the wearer) when the diaper is worn. Moreover, although the phrase a skin contact surface may be used hereafter, a skin contact surface is a surface turned to the wearer's skin side at the time of diaper wearing.

  Examples of the side sheets include nonwoven fabrics, film sheets, and paper. From the viewpoint of leakproofness, the side sheet is preferably formed of a liquid-impervious or impervious hydrophobic nonwoven fabric, leakproof film sheet, or the like. The number of sheets may be one, or may be two or more in combination with a functional sheet or the like.

Furthermore, in addition to the top sheet 16, the absorber 10, the back sheet 17, and the side sheets, members may be appropriately present according to the application and function.
Furthermore, as shown in FIG. 5, an intermediate sheet 19 (base) may be disposed between the top sheet 16 and the absorber 10.
The intermediate sheet 19 has a function to draw in and diffuse the excreted liquid and a function to hold the liquid, one to reduce the amount of liquid return, one to suppress the leakage of the water absorbing polymer, one to suppress the collapse of the absorber, etc. Used.
Examples of the sheet having such performance include non-woven fabric, film, porous body, and the like containing fibers having hydrophilicity or containing fibers treated with a hydrophilic oil and the like. Examples of fibers for the intermediate sheet include (1) wood pulp such as softwood kraft pulp and hardwood kraft pulp, natural cellulose fibers such as non-wood pulp such as cotton pulp and straw pulp, and (2) regenerated cellulose fibers such as rayon and cupra , (3) Hydrophilic synthetic fibers such as polyvinyl alcohol fibers and polyacrylonitrile fibers, (4) Surfactants of synthetic fibers such as polyethylene terephthalate (PET) fibers, polyethylene (PE) fibers, polypropylene (PP) fibers and polyester fibers The thing etc. which were hydrophilized by this, etc. are mentioned, These 1 type can be used individually or in mixture of 2 or more types.
As the intermediate sheet 19, for example, paper such as tissue paper, woven fabric, non-woven fabric, knitted fabric, parchment, papyrus, pulp fiber stack, etc. can be used. Examples of the non-woven fabric include chemical bond non-woven fabric, thermal bond non-woven fabric, air-laid non-woven fabric, spun lace non-woven fabric, spun bond non-woven fabric, meltblown non-woven fabric, needle punched non-woven fabric, stitch bonded non-woven fabric and the like.
These sheets may be in the form of a single layer, or may have a multilayer structure in which a plurality of layers are laminated to form a single sheet. In addition, a three-dimensional network is formed in the structure by a sheet having stretchability (for example, a non-woven fabric (elastic non-woven fabric) containing fibers containing an elastic resin as constituent fibers), a film (elastic film) containing an elastic resin, or foaming. Or the like may be used).
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. 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 disposed only between the top sheet 16 and the absorbent body 10, or may be disposed between the absorbent body 10 and the back sheet 17, and the absorbent sheet 10 may be packaged. It may be arranged in the same manner.

  The diaper 50 as the absorbent article according to the present invention achieves high absorption capacity and high absorption speed at the same time by the action of the absorbent body 10, and uses a stretchable sheet for the base sheet (not shown) of the absorbent body 10 The body is deformed according to the complex undulating skin surface, and it conforms to the human body adaptability that abuts on the surface without gaps and the movement of the wearer's body, and keeps the skin surface in contact with the skin surface It has the operation followability. And the diaper 50 has the versatility that it can be used similarly to a normal expansion | deployment type | mold diaper.

  The absorbent article is not limited to the above embodiment, and can be applied to another type of absorbent article of this type, such as disposable diapers, incontinence pads, incontinence liners and the like. Moreover, it is effective not only to urine but also to menstrual blood, olmono, soft stools 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 according to the application and function. In addition, the material in the surface sheet 16 of the said embodiment, the absorber 10, and the back surface sheet 17, the conditions in a manufacturing method, and the dimension specification of a product are not specifically limited, The various materials used normally can be used.

  Hereinafter, the present invention will be described in more detail by way of examples and comparative examples. The present invention is not limited to these examples.

Example 1
First, the method of calculating the average particle size of the water-absorbing polymer will be described below.
The average particle size is calculated by classifying 100 g of the water-absorbing polymer using a sieve according to JIS Z-8801-1982, and determining the average particle size from the mass fraction of each fraction.

Next, a method of measuring the amount of water absorption of the water absorbing polymer will be described below.
The amount of water absorption was measured by swelling 1.00 g of a water-absorbing polymer at room temperature (20 ± 5 ° C.) with 150 mL of room temperature (20 ± 5 ° C.) physiological saline (0.9% NaCl aqueous solution, manufactured by Otsuka Pharmaceutical) for 30 minutes Then, it is placed in a 250-mesh non-woven bag, dewatered with a centrifuge at 143G for 10 minutes, and the total mass (total mass) after dewatering is measured. And according to following Formula (1), the retention amount of the physiological saline after centrifugal dehydration is measured, and let this value be water absorption amount.

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 non-woven bag liquid remaining amount = (non-woven bag mass after centrifugal dehydration)-(non-woven bag mass).

Next, with reference to FIG. 6, a measuring apparatus for performing the method of measuring the amount of absorption under pressure will be described.
As shown in FIG. 6 (1), a column 210 in which a mesh 213 (250 mesh) is attached to the lower end opening 212 of a cylinder 211 (inner diameter 30 mm) erected vertically is prepared. Into it, 0.500 g of the water absorbing polymer 22 (particles) is put so as to have a uniform thickness. Then, a weight 221 (weight to which a pressure of 2.0 kPa is applied) slightly smaller than the outer diameter of 30 mm is placed on the water absorbing polymer 22.
In a 100 mL beaker 230, 100 mL of saline 231 (0.9 mass% aqueous sodium chloride) at room temperature (20 ± 5 ° C.) is poured. Then, the mesh 210 is not attached to the bottom of the beaker 230, and the column 210 is immersed in the physiological saline 231, and left in this state for 1 hour.
Thereafter, the column 210 is taken out of the beaker 130, and drained for 15 minutes in a state where the weight 221 is placed on the water absorbing polymer 22 as shown in FIG. 6 (2). 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, synthesis examples of the water-absorbing polymer will be described below.
As Synthesis Example 1, the synthesis of the water-absorbing polymer I was performed as follows.
In Synthesis Example 1, firstly, a stirrer, a reflux condenser, a monomer dropping port, a nitrogen gas introducing pipe, and a SUS304 5 L volume reaction vessel (using anchor wings) attached with a thermometer as a dispersing agent, manufactured by Kao Co., Ltd. Ethylene lauryl ether sodium sulfate (trade name Emar 20C) 0.11% [mass of acrylic acid] was charged, and 1600 mL of cyclohexane was added. The mixture was stirred under nitrogen atmosphere and heated to an internal temperature of 77 ° C.

  Separately, charge 80% acrylic acid and ion-exchanged water from Toagosei Co., Ltd. in a 2 L three-necked flask, and while cooling on ice, add a 48% aqueous solution of caustic soda made by Asahi Glass Co., Ltd. 1054 g of a sodium acid aqueous solution (72% neutralized product, concentration about 48%) was obtained. A solution of 0.18 g of N-acylated glutamic acid soda (trade name: Amisoft GS-11F) manufactured by Ajinomoto Co., Ltd. in 3 g of ion-exchanged water is added to this aqueous monomer solution, and after stirring for a while, 264 g (hereinafter referred to as A monomer aqueous solution A), 264 g (hereinafter, monomer aqueous solution B), and 528 g (hereinafter, monomer aqueous solution C) were divided into three.

Next, Wako Pure Chemical Industries, Ltd. product 2,2'-azobis (2-amidinopropane) dihydrochloride (brand name V-50) 0.12 g, Kao Corporation polyethylene glycol (PEG 6000) 0.20 g, ion 14 g of exchange water was mixed and dissolved to prepare an initiator (A) aqueous solution. Further, 0.49 g of sodium persulfate manufactured by Wako Pure Chemical Industries, Ltd. was dissolved in 10 g of ion exchange water to prepare an initiator (B) aqueous solution. Further, an aqueous solution of titanium citrate (mixture of 50% citric acid and an aqueous solution of titanyl sulfate in a mass ratio of 20/27) was prepared.
7.2 g of initiator (A) aqueous solution is added to monomer aqueous solution A to prepare monomer A, and 7.2 g of initiator (A) aqueous solution and 1.5 g of titanium citrate aqueous solution are added to monomer aqueous solution B to prepare monomer B Then, 10.5 g of an initiator (B) aqueous solution and 3 g of a titanium citrate aqueous solution were added to a monomer aqueous solution C to prepare a monomer C.

  The monomer A, the monomer B and the monomer C, which were allowed to stand for 5 minutes or longer, were dropped sequentially over about 60 minutes from the monomer dropping port of the 5 L reaction container described above and polymerized. After completion of monomer dropping, azeotropic dehydration is performed using a dehydration pipe to adjust the water content of the water absorbing polymer (hydrogel) to 60%, and ethylene glycol diglycidyl ether (product of Nagase Chemical Industries, Ltd.) as a crosslinking agent A solution of 0.33 g of the name Denacol EX-810) in 10 g of water was added. Thereafter, the mixture was further subjected to azeotropic dehydration, and after cooling, cyclohexane was removed and dried under reduced pressure to obtain a water absorbing polymer. After removing coarse particles with a sieve having an opening of 850 microns, 0.5 parts 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, the synthesis of the water-absorbing polymer II was carried out as follows.
In Synthesis Example 2 above, 0.33 g of ethylene glycol diglycidyl ether (trade name Denacol EX-810) manufactured by Nagase Chemical Industries, Ltd. is changed to 0.18 g as a crosslinking agent in Synthesis Example 1 described above, and the water absorbing polymer is changed. Obtained. To this water-absorbing polymer, 1% (based on the weight of the water-absorbing polymer) was diluted with water and added to a quaternary ammonium salt (trade name Cortamine 86W, manufactured by Kao Corp.) and dried. After removing coarse particles with a sieve of 850 μm, 100 parts of this polymer particle is dry-blended with 0.5 parts of Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd.) to obtain a water absorbing polymer II. Obtained.

As Synthesis Example 3, the synthesis of the water-absorbing polymer III was carried out as follows.
Synthesis Example 3 is the same as Synthesis Example 2 described above except that 0.18 g of ethylene glycol diglycidyl ether (trade name Denacol EX-810) manufactured by Nagase Chemical Industries, Ltd. as a crosslinking agent is changed to 0.25 g. To obtain a water absorbing polymer III.

As Synthesis Example 4, the synthesis of the water absorbing polymer IV was performed as follows.
Nippon Oil and Fats Co., Ltd. sodium polyoxyethylene lauryl ether sulfate as a dispersant in a SUS304 5 L reaction vessel (using anchor blades) fitted with a stirrer, reflux condenser, monomer dropping port, nitrogen gas inlet pipe, and thermometer Charge under the trade name Persoft EL) 0.06% [to acrylic acid heavy mass] and Stearyl methyl taurine sodium (trade name Nikkol SMT) 0.04% [to acrylic acid mass] manufactured by Nikko Chemicals Co., Ltd. and heptane 1600 mL added. The mixture was stirred under nitrogen atmosphere and heated to an internal temperature of 88 ° C.

  Separately, charge 80% acrylic acid and ion-exchanged water from Toagosei Co., Ltd. in a 2 L three-necked flask, and while cooling on ice, add a 48% aqueous solution of caustic soda made by Asahi Glass Co., Ltd. 1054 g of a sodium acid aqueous solution (72% neutralized product, concentration about 48%) was obtained. A solution of 0.25 g of N-acylated glutamic acid soda (trade name: Amisoft GS-11F) manufactured by Ajinomoto Co., Ltd. in 3 g of ion-exchanged water is added to this aqueous monomer solution, and after being stirred for a while, 264 g (hereinafter referred to as The monomer aqueous solution D), 264 g (hereinafter, monomer aqueous solution E), and 528 g (hereinafter, monomer aqueous solution F) were divided into three.

Then, Wako Pure Chemical Industries Ltd. product 2,2'-azobis (2-amidino propane) dihydrochloride (brand name V-50) 0.041 g, Kao Corporation polyethylene glycol (PEG6000) 0.20 g, ion 9 g of exchanged water was mixed and dissolved to prepare an initiator (C) aqueous solution. Further, 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 initiator (D) aqueous solution. Furthermore, an aqueous solution of citric acid (a mixture of 50% citric acid and an aqueous solution of titanyl sulfate in a mass ratio of 20/54) was prepared.
2.3 g of initiator (C) aqueous solution is added to monomer aqueous solution D to prepare monomer A, and 6.9 g of initiator (C) aqueous solution and 1.5 g of titanium citrate aqueous solution are added to monomer aqueous solution E to prepare monomer E Then, 10.5 g of an initiator (D) aqueous solution and 3 g of a titanium citrate aqueous solution were added to a monomer aqueous solution F to prepare a monomer F.

  A monomer D, a monomer E and a monomer F which were allowed to stand for 5 minutes or longer were sequentially dropped over about 60 minutes from the monomer dropping port of the 5 L reaction container described above and polymerized. After completion of the polymerization, azeotropic dehydration is carried out using a dehydration pipe to adjust the water content of the water-absorbing polymer (hydrogel) to 60%, and ethylene glycol diglycidyl ether (trade name, manufactured by Nagase Chemical Industries, Ltd.) as a crosslinking agent. A solution of 0.12 g of Denacol EX-810) in 10 g of water was added. Thereafter, the mixture was further subjected to azeotropic dehydration, and after cooling, heptane was removed and dried under reduced pressure to obtain a water absorbing polymer. After removing coarse particles with a sieve of 850 μm, 100 parts of this polymer particle is dry blended with 0.5 parts of Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd.) to obtain a water absorbing polymer IV. The

  The average particle diameter, the water absorption amount, and the absorption amount under 2 kPa pressurization of each of the water-absorbent polymers I, II, III and IV in the above-mentioned Synthesis Examples 1 to 4 are as shown in Table 1.

As Example 1, the absorbent article which comprises the absorber of the shape shown in FIG. 7 as follows was produced.
As shown in FIG. 7 (1), a laminate 23 of pulp sheet 21S and water-absorbing polymer 22 (weight 50 g / m ² ) is used as the water-absorbing polymer 22 using the water-absorbing polymer III obtained in Synthesis Example 3. A water absorbing polymer 22 was dispersed between the four layers of the pulp sheet 21S at a basis weight of 100 g / m ² of each layer and three layers were dispersed. As shown in FIG. 7 (2), this 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 with 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 absorber block 24 cut above on the base sheet 13 has a horizontal gap e = 5 mm and a vertical distance d = 5 mm, and arranged and fixed at 3 × 7 in width.
Next, a tissue paper (not shown) with 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. Moreover, the thickness of the absorber was 3 mm.
Although not shown, the absorbent body obtained by pressing was disposed between the top sheet and the back sheet to obtain an absorbent article. Kao Co., Ltd.'s surface material of Merry's is used for the surface sheet that is the skin contact surface, and the liquid-impermeable back sheet is the back sheet of Kao's product name, Merry's It was.

Examples 2, 3 and 4 and Comparative Examples As Example 2, the same operation as in Example 1 is carried out except that the water-absorbing polymer III is changed to the water-absorbing polymer IV obtained in Synthesis Example 4 in Example 1. , To obtain an absorbent article.

As Example 3, after arranging and fixing the above-mentioned cut absorber blocks 24 on the base sheet 13 in 3 × 7 columns on the base sheet 13, a portion of the groove (width 5 mm) between the absorber blocks 24 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 disposed on the base sheet 13 side.
Next, a tissue paper (not shown) with 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. Moreover, the thickness of the absorber was 3 mm, and the depth of the recess was 1.5 mm (50%).
Thereafter, the same operation as in Example 1 was performed to obtain an absorbent article. When the pressed absorber was placed between the top sheet and the back sheet, a pulp continuous layer was placed on the back sheet side.

  As Example 4, when arrange | positioned the pressed absorber in a front sheet and a back sheet in above-mentioned Example 3, up-down was reversed and the pulp continuous layer was distribute | arranged to the surface sheet side.

As Comparative Example 1, an absorbent article was obtained by performing the same operation as in Example 1 except that the water absorbent polymer III was changed to the water absorbent polymer I obtained in Synthesis Example 1 in Example 1.
The mass ratio represented by [mass of pulp] / [mass of water absorbing polymer] in the absorbent was 1 / 1.5, and the thickness of the absorbent 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 absorbent polymer III was changed to the water absorbent polymer II obtained in Synthesis Example 2 in Example 1.
The mass ratio represented by [mass of pulp] / [mass of water absorbing polymer] in the absorbent was 1 / 1.5, and the thickness of the absorbent was 3 mm.
As Comparative Example 3, in Example 1, a laminate of the pulp and the water-absorbent polymer (having a basis weight of 80 g / m ² of each layer between four layers of pulp sheet having a basis weight of 50 g / m ² ) The three-layer dispersion was cut to a width of 100 mm and a height of 375 mm to obtain an absorbent article. The basis weight of the water-absorbing polymer was lowered by the amount of increase in the area of the absorbent than 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 absorbent was 1 / 1.2, and the thickness of the absorbent was 3 mm.
As Comparative Example 4, in Comparative Example 1, a laminate of the pulp and the water-absorbent polymer (having a basis weight of 90 g / m ² of each layer between four layers of pulp sheet having a basis weight of 50 g / m ² ) The three-layer dispersion was cut to a width of 100 mm and a height of 375 mm to obtain an absorbent article. The area of the absorber is larger than that of Comparative Example 1, and the basis weight of the water-absorbing polymer is lowered, and the amount of the water-absorbing polymer used is 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, methods of measuring the absorption speed and the liquid return amount of the absorbent article will be described. As an example, the case of baby diapers (M size) will be described.
An acrylic cylinder with an inner diameter of 35 mm is placed 150 mm from the ventral 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 is applied while applying a load of 2.0 kPa to the entire absorbent article. The solution was injected while maintaining the height of 10 mm. The lowermost portion of the cylinder is provided with an acrylic plate of a size covering the entire absorbent article. 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 again injected, and the absorption time was measured (absorption time 2). This operation was further repeated twice, and a total of 160 g of physiological saline was injected, and the absorption time was measured (absorption time 3, 4). The temperature of the test atmosphere was room temperature (20 ± 5 ° C.), and the temperature of the artificial urine was room temperature (20 ± 5 ° C.).
Ten minutes after the completion of injection, the 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 a 5 mm thick, 100 mm × 100 mm acrylic plate, and after 2 minutes, the mass of the filter paper was measured (W2), and the liquid return amount was calculated according to the following equation.

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

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

Next, the evaluation method regarding the absorption amount of an absorbent article is demonstrated below.
Place the produced absorbent article on an acrylic plate inclined at 20 degrees (bent side edge part is lower side), put an acrylic plate and a weight on it, and apply a load of 2.0 kPa to the whole absorbent article The In this state, artificial urine colored at a position of 200 mm from the upper end of the absorbent article is repeatedly injected at a fixed amount and at regular intervals, and the injection amount until it leaks from the lower end of the absorbent Compared. The temperature of the test atmosphere was room temperature (20 ± 5 ° C.), and the artificial urine was room temperature (20 ± 5 ° C.).
The relative value when the absorption capacity of Comparative Example 4 was 1.0 was calculated using the following formula.

  Absorbent capacity (relative value) = (absorbed capacity of sample) / (absorbed capacity of comparative example 4)

  The composition of artificial urine is as shown in Table 2.

  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 "the position of a groove | channel" in Tables 3-5, it showed by schematic structure sectional drawing of the absorbent article 50 in FIG. The reference numerals shown in the figure are the same as the reference numerals of the respective components described above.

  As shown in Tables 3 to 5 above, in each of Examples 1 to 4, the absorption time of the liquid is less than 30 seconds in the first time, and the absorption time is less than 60 seconds in the second to fourth absorption. The On the other hand, in the comparative example, in the comparative example 1, the evaluation result almost equivalent to that of the example was obtained 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 in which the absorbers were not used, the second and subsequent absorption times took 60 seconds or more, and the absorption time was prolonged. As a result, it was found that the absorption performance of the liquid of the example is maintained high from the start of use to the end of absorption repeatedly.

  Thus, for example, assuming that the water absorption polymer 22 used in the absorbent body 10 of the present invention has about 40 cc of urine per infant, the first excretion (voiding), the second, the third, and the fourth Even if it is excreted, it is difficult for the water-absorbent polymer 22 to swell even if it absorbs excreted liquid (urine), and therefore the state of the groove 11 at the time of the first expulsion is maintained. For this reason, the groove 11 is not clogged by the water absorbing polymer 22, and the liquid permeability of the groove 11 is secured. As a result, the rate of absorption of the excretory fluid is increased.

  In Examples 1 to 4, Comparative Example 1 using a water-absorbing polymer having a small amount of liquid reversion and less water absorption, Comparative Example 2 using a water-absorbing polymer having a low absorption under pressure, and In the comparative example 3 which does not have a 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 in 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, it is possible to flow 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, whereby the water-absorbing polymer is crushed and protrudes into the groove 11, and in the worst case, the groove 11 As it is blocked, it is difficult to flow through the groove 11. For this reason, in the second and subsequent discharges, since the draining liquid becomes difficult to flow or does not flow in the groove 11, the liquid can not be sufficiently diffused, and the amount of liquid return becomes large.
On the other hand, in the case of the absorbent polymer used in each example, the water-absorbing polymer hardly swells even after the second and subsequent discharges, so that the drainage liquid is diffused throughout the absorber without blocking the groove 11 Since it can be absorbed, the amount of liquid return can be less than 1.5 g.

Furthermore, the absorption capacity of each of Examples 1 to 4 is 1.0 as compared with Comparative Example 4 in which the amount of the water-absorbing polymer used is 1.13 times more than that of Example 1, and is equivalent to that of Comparative Example 4. It turned out that it was absorption capacity. That is, it was found that each example had a sufficient absorption capacity.
As described above, since each example has a sufficient absorption capacity, in each example, the liquid return amount is reduced to less than 1.5 g, while in Comparative Example 1, the absorption capacity is 0.8. And the amount of liquid return increases. Further, in Comparative Example 3, the same amount of the same water-absorbent polymer III as in Example 1 is used, but since there is no groove, the absorption capacity as an absorber also becomes as low as 0.8, and the liquid return amount is Become more.

  As explained above, according to the absorbent body 10 of the present invention and the absorbent article 50 using the absorbent body 10, both of the high absorption amount and the high absorption rate can be achieved in the repeated absorption of the excretory liquid after long use. Therefore, the amount of liquid return is small and high absorption performance can be exhibited.

Reference Signs List 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 (6)

An absorbent having pulp and a water absorbing polymer,
The absorber has a plurality of recesses extending in the intersecting direction, and the plurality of recesses are connected to each other to form a flow channel for the drainage liquid in the absorber, and 20% or more of the thickness of the absorber 95 Have a depth of less than%,
The density of the absorber at the bottom of the recess is lower than the density of the absorber at a portion other than the bottom of the recess including the portion adjacent to the bottom of the recess;
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,
An absorbent body, wherein the water-absorbing polymer has a water absorption amount of 30 g / g to 45 g / g and an absorption amount of liquid under a pressure of 2 kPa of 20 g / g to 40 g / g.   The absorbent according to claim 1, wherein the water-absorbent polymer has a liquid absorption of 20 g / g or more and 35 g / g or less under a pressure of 2 kPa.   The absorber according to claim 1 or 2, wherein a total area of the recesses when viewed in plan is 10% or more and 40% or less with respect to an area of the absorber viewed in plan.   The thickness of the said absorber is 0.5 mm or more and 20 mm or less, The absorber of any one of Claims 1-3.   The width | variety of the said recessed part is 1 mm or more and 10 mm or less, The absorber of any one of Claims 1-4. A liquid-permeable top sheet disposed on the skin contact surface side;
A liquid impermeable back sheet disposed on the non-skin contact side;
And an absorber disposed between the sheets.
The absorbent article which is an absorber according to any one of claims 1 to 5 as the absorber.

Images