JP2015188709A - absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbent article capable of preventing seepage (re-wetting back) of liquid excretory substance from a storage layer to a liquid-permeable layer.SOLUTION: A diaper (1) includes a top sheet (2) having through-holes (21), a back sheet (3), and an absorber (4) provided between the top sheet (2) and the back sheet (3), where the absorber (4) includes an absorbent core (41) containing a high-absorbent polymer material, and a porous particle layer (42) provided on the top sheet (2) side of the absorbent core (41). The grain size of the porous particles contained in the porous particle layer (42) is 2-10 mm, and the density of the porous particles is 2-40 particles/cm.

Description

  The present invention relates to an absorbent article.

  An absorbent article comprising a liquid permeable layer (top sheet), a liquid impermeable layer (back sheet), and an absorbent core containing a superabsorbent polymer material as an absorbent article, Absorbent articles are known in which a reservoir layer (liquid capture layer) containing chemically cross-linked cellulose fibers or the like is provided between the absorbent layer and the absorbent core (Patent Documents 1 to 4).

International Publication WO2004 / 071363 Pamphlet International Publication WO2004 / 071539 Pamphlet International Publication WO2007 / 057869 Pamphlet International Publication WO2008 / 155711 Pamphlet

  In the absorbent articles described in Patent Literatures 1 to 4, the storage layer temporarily stores the liquid excrement excreted from the user, and distributes and supplies the stored liquid excrement to the absorbent core. However, in the absorbent articles described in Patent Documents 1 to 4, liquid excrement tends to remain in the reservoir. Therefore, when the absorbent article is pressurized (for example, pressurized by the user's body weight), liquid excretion from the reservoir layer to the liquid permeable layer (rewetting back) is likely to occur, and the user is sticky. , There is a risk of giving a sense of incongruity such as a wet feeling or causing skin troubles such as a rash.

  Then, an object of this invention is to provide the absorbent article which can prevent the exudation (rewetting back) of the liquid excretion from a storage layer to a liquid-permeable layer.

In order to solve the above problems, the present invention provides an absorption device comprising a liquid-permeable layer, a liquid-impermeable layer, and an absorber provided between the liquid-permeable layer and the liquid-impermeable layer. The liquid permeable layer has a through-hole penetrating the liquid permeable layer in the thickness direction, and the absorber includes an absorbent core containing a superabsorbent polymer material, A porous particle layer provided on the liquid permeable layer side of the absorbent core, and the particle size of the porous particles contained in the porous particle layer is 2 to 10 mm, and the porous particle layer The number of porous particles per unit volume of the absorbent article is 2 to 40 / cm ³ .

  ADVANTAGE OF THE INVENTION According to this invention, the absorbent article which can prevent the exudation (rewet back) of the liquid excretion from a storage layer to a liquid-permeable layer is provided.

FIG. 1 is a perspective view of a disposable diaper according to an embodiment of the absorbent article of the present invention. FIG. 2 is a developed plan view showing a state in which the connection between the front surface portion and the rear surface portion is released in the disposable diaper of FIG. 1. FIG. 3 is an exploded perspective view of the disposable diaper of FIG. Fig.4 (a) is a top view of the absorber which the disposable diaper of FIG. 1 comprises, FIG.4 (b) is the sectional view on the AA line of Fig.4 (a). FIG. 5 is a diagram showing an embodiment of the manufacturing process of the absorbent body of the present invention. Fig.6 (a) is a top view of the absorber which concerns on another embodiment, FIG.6 (b) is the sectional view on the AA line of Fig.6 (a). Fig.7 (a) is a top view of the absorber which concerns on another embodiment, FIG.7 (b) is the sectional view on the AA line of Fig.7 (a). Fig.8 (a) is a top view of the absorber which concerns on another embodiment, FIG.8 (b) is the sectional view on the AA line of Fig.8 (a). FIG. 9 is a diagram showing images of the porous particles before and after binarization in the measurement of the particle diameter of the porous particles.

Hereinafter, the absorbent article of the present invention will be described.
The absorbent article which concerns on aspect 1 is an absorbent article provided with the liquid permeable layer, the liquid impermeable layer, and the absorber provided between the said liquid permeable layer and the said liquid impermeable layer. The liquid permeable layer has a through-hole penetrating the liquid permeable layer in the thickness direction, and the absorber includes an absorbent core containing a superabsorbent polymer material, and the absorbent core. A porous particle layer provided on the liquid permeable layer side, the particle size of the porous particles contained in the porous particle layer is 2 to 10 mm, and the unit volume of the porous particle layer The number of porous particles per hit is 2 to 40 / cm ³ in the absorbent article.

  A through-hole penetrating the liquid-permeable layer in the thickness direction is formed in the liquid-permeable layer, and this through-hole functions as a liquid-permeable hole. Therefore, the user's liquid excrement supplied to the liquid permeable layer can permeate the liquid permeable layer through the through hole. The through-hole formed in the liquid-permeable layer is particularly useful for improving the permeability of high-viscosity liquid excretion (for example, watery feces, menstrual blood, etc.) having a high solid content such as fiber. . The liquid permeability of the liquid permeable layer is not limited to the liquid permeability based on the through hole. For example, when the liquid permeable layer is a nonwoven fabric having through holes, the liquid permeable layer has liquid permeability based on the form of the nonwoven fabric in addition to the liquid permeability based on the through holes.

  The liquid excrement that has passed through the liquid permeable layer diffuses in the porous particle layer and is temporarily stored in the porous particle layer. That is, the porous particle layer functions as a storage layer (liquid excretion capturing layer) that temporarily stores liquid excretion that has passed through the liquid permeable layer. When liquid excrement is temporarily stored in the porous particle layer, the voids between the porous particles and the voids in the porous particles function as a flow path for the liquid excrement, Spreads quickly. Accordingly, the liquid excreta can be efficiently transferred from the porous particle layer to the absorbent core. The term “temporarily stored” means that the liquid excretion that has permeated through the liquid permeable layer is temporarily absorbed and retained by the porous particle layer, but the porous particle layer then absorbs the core. It is used with the intention of being absorbed and retained by the absorbent core in the end. However, all of the liquid excreta stored in the porous particle layer does not move from the porous particle layer to the absorbent core, but partially remains in the porous particle layer.

When liquid excrement moves from the porous particle layer to the absorbent core, among the components of the liquid excretion, moisture easily moves from the porous particle layer to the absorbent core, but solids such as fibers are porous. Easily trapped in the particle layer. Therefore, the movement of the liquid excrement remaining in the porous particle layer as a fluid becomes slow, thereby preventing the liquid excretion from exuding (rewetting back) from the porous particle layer to the liquid permeable layer. it can. The effect of preventing the rewet back of liquid excrement by such a porous particle layer includes the range of the particle size (mm) and density (pieces / cm ³ ) of the porous particles contained in the porous particle layer, and the top sheet. It changes significantly based on the presence or absence of through-holes formed on the surface.

That is, the effect of preventing rewet back on high-viscosity liquid excrement (for example, watery stool, menstrual blood, etc.) with a high solid content such as fibrous material is that the particle size of the porous particles is less than 2 mm, and the porous The particle diameter of the porous particles is 2 mm or more and the density of the porous particles is 40 particles / cm ³ or less than the case where the density of the porous particles exceeds 40 particles / cm ³ (see Comparative Example 4). The case (see Examples 1-6) is significantly higher. Similarly, the effect of preventing rewet back on low-viscosity liquid excrement (for example, urine) having a low solid content such as fiber is higher in the latter than in the former.

Further, the effect of preventing rewet back on high-viscosity liquid excrement is when the particle size of the porous particles exceeds 10 mm and the density of the porous particles is less than 2 particles / cm ³ (see Comparative Example 3), There is no significant difference between the case where the particle size of the porous particles is 10 mm or less and the density of the porous particles is 2 particles / cm ³ or more (see Examples 1 to 6). However, the effect of preventing rewet back on low-viscosity liquid excrement is significantly higher in the latter than in the former.

  Moreover, when the particle size and density of the porous particles are about the same, but the two cases where the presence or absence of through-holes formed in the liquid permeable layer are different (see Example 1 and Comparative Example 5) are compared, the viscosity is high. The effect of preventing rewet back on liquid excrement is more effective when the through-hole is formed in the liquid-permeable layer than when the through-hole is not formed in the liquid-permeable layer (see Comparative Example 5) (see Example 1). ) Is significantly higher. Note that the effect of preventing rewet back on low-viscosity liquid excrement generally tends to decrease by forming a through-hole in the liquid-permeable layer. However, when a porous particle layer is present, it penetrates into the liquid-permeable layer. Even if the holes are formed, such a downward tendency is not observed.

As described above, the effect of preventing rewet back of liquid excrement by the porous particle layer includes the range of the particle size (mm) and density (pieces / cm ³ ) of the porous particles contained in the porous particle layer, and the liquid It changes significantly based on the presence or absence of through-holes formed in the permeable layer. In consideration of this, in the absorbent article according to aspect 1, through holes are formed in the liquid permeable layer, the particle diameter of the porous particles is 2 to 10 mm, and the density of the porous particles is It is adjusted to 2 to 40 pieces / cm ³ . Therefore, according to the absorbent article which concerns on aspect 1, even if liquid excrement is high viscosity or low viscosity, exudation of liquid excretion from a porous particle layer to a liquid permeable layer (rewetting back) ) Can be effectively prevented. For this reason, the absorbent article which concerns on aspect 1 absorbs not only low-viscosity liquid excrement (for example, urine etc.) but high-viscosity liquid excrement (for example, watery feces, menstrual blood, etc.). It is particularly useful as an article (for example, baby diapers, sanitary napkins, etc.).

  In a preferred embodiment (aspect 2) of the absorbent article according to aspect 1, the porous particles are one or more kinds of particles selected from fiber balls and porous cellulose particles.

  In a preferred aspect (Aspect 3) of the absorbent article according to Aspect 2, the fiber ball includes one or more fibers selected from hydrophilic fibers and hydrophilized hydrophobic fibers. In the aspect 3, since the fiber ball has hydrophilicity, when the liquid excrement diffuses through the porous particle layer, the voids in the porous particle easily function as a flow path for the liquid excrement. Therefore, in aspect 3, the porous particle layer can effectively exhibit the function as a reservoir. In addition, since the porous cellulose particle of aspect 2 has hydrophilicity, the same effect as the fiber ball which has hydrophilicity can be exhibited.

  In a preferred aspect (Aspect 4) of the absorbent article according to Aspect 3, the fiber ball is composed of one or more hydrophilic materials selected from cotton, pulp and paper. In the aspect 4, since the fiber ball has hydrophilicity, when the liquid excrement diffuses through the porous particle layer, the voids in the porous particle easily function as a flow path for the liquid excrement. Therefore, in aspect 4, the porous particle layer can effectively exhibit the function as the reservoir layer.

  In a preferred embodiment (embodiment 5) of the absorbent article according to any one of Embodiments 2 to 4, the mass per one porous particle is 3 to 35 g. Aspect 5 can be combined with one or more aspects of Aspects 2-4. In aspect 5, since the porous particles are fiber balls or porous cellulose particles having a particle diameter of 2 to 10 mm, and the mass per porous particle is 3 to 35 mg, There are enough voids. Therefore, when the liquid diffuses through the porous particle layer, the voids in the porous particle can easily function as a flow path for liquid excreta, and the porous particle layer can effectively function as a reservoir. Can do.

  In a preferred aspect (Aspect 6) of the absorbent article according to any one of Aspects 1 to 5, the diameter of the through hole is less than 10 mm. Aspect 6 can be combined with one or more aspects of Aspects 1-5. In the aspect 6, leakage of the porous particles from the through hole can be prevented.

  In a preferred aspect (Aspect 7) of the absorbent article according to any one of Aspects 1 to 6, the through holes are formed so that the liquid permeable layer has a porosity of 5 to 90%. Aspect 7 can be combined with one or more aspects of Aspects 1-6.

  In a preferred aspect (Aspect 8) of the absorbent article according to any one of Aspects 1 to 7, the porous particle layer, the liquid permeable layer and / or the absorbent core are bonded with an adhesive. Yes. Aspect 8 can be combined with one or more of Aspects 1-7.

The kind and application of the absorbent article of the present invention are not particularly limited. Examples of absorbent articles include disposable diapers, sanitary napkins, panty liners, incontinence pads, and hygiene articles such as sweat removal sheets. These may be intended for humans and other than humans such as pets. Animals may be targeted. The liquid to be absorbed by the absorbent article of the present invention is not particularly limited, and examples thereof include liquid excrement (for example, urine, watery stool, menstrual blood, etc.) of the user.
Hereinafter, an embodiment of the absorbent article of the present invention will be described based on the drawings, taking a disposable diaper as an example.

  As shown in FIG.1 and FIG.2, the diaper 1 which concerns on one Embodiment of the absorbent article of this invention is the front part 11 applied to a user's abdomen, and the intermediate part 12 applied to a user's crotch part. And a rear surface portion 13 applied to the user's buttocks and / or back. 2, the X-axis direction is the width direction of the diaper 1 in the unfolded state, the Y-axis direction is the longitudinal direction of the diaper 1 in the unfolded state, and the plane direction extending in the X-axis Y-axis direction is the diaper 1 in the unfolded state. Corresponds to the plane direction. The same applies to the other drawings.

  As shown in FIG. 1, in the joint portions 14 a and 14 b, the side portions 111 a and 111 b of the front surface portion 11 and the both side portions 131 a and 131 b of the rear surface portion 13 are joined to each other. A waist opening is formed by the end portion 132 of the surface portion 13, and leg openings are formed by both side portions 121 a and 121 b of the intermediate portion 12, and the diaper 1 has a pants-type shape. .

  As shown in FIGS. 1 to 3, the diaper 1 includes a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and an absorbent body 4 provided between the top sheet 2 and the back sheet 3. It has. Hereinafter, these members will be described.

<Top sheet>
The top sheet 2 is an example of a liquid permeable layer.
As shown in FIGS. 1-3, a part of top sheet 2 (a part of arrangement | positioning area | region of the absorber 4) is exposed from the opening part 61 formed in the approximate center of the cover sheet 6 mentioned later, and the diaper 1 It constitutes the skin side surface. The region where the absorber 4 is disposed is a region where the absorber 4 overlaps the top sheet 2 when the absorber 4 is projected onto the top sheet 2, and in the present embodiment is substantially the entire top sheet 2 (FIG. 2).

  As shown in FIG. 3, the top sheet 2 has a plurality of through holes 21. In FIGS. 1 and 2, the through hole 21 is omitted for simplification of the drawing. The through hole 21 penetrates the top sheet 2 in the thickness direction and reaches from the one surface of the top sheet 2 to the other surface, and functions as a liquid permeable hole. Therefore, the liquid excrement of the user can permeate the top sheet 2 through the through hole 21. The through-hole 21 formed in the top sheet 2 is particularly useful for improving the permeability of high-viscosity liquid excretion (for example, watery feces, menstrual blood, etc.) having a high solid content such as fiber. . The liquid permeability of the top sheet 2 is not limited to the liquid permeability based on the through hole 21. For example, when the top sheet 2 is a non-woven fabric having through-holes 21, the top sheet 2 has liquid permeability based on the form of the non-woven fabric in addition to the liquid permeability based on the through-holes 21.

  The through hole 21 has an opening ratio of the top sheet 2 (a ratio of the total area of the through holes 21 to the area of the top sheet 2), preferably 5 to 90%, more preferably 20 to 90%, and still more preferably. It is formed to be 25 to 80%. If the open area ratio is less than 5%, the liquid permeability of the top sheet 2 (particularly the permeability of high-viscosity liquid excreta) may be insufficient. There is a possibility that the re-wet back of the excrement (seepage from the top sheet 2) becomes remarkable.

  The measurement of the area of the through hole is performed as follows in consideration of the fact that the shape of the through hole is not necessarily a perfect circle. By extracting the through-hole region from the through-hole image by binarizing the through-hole image taken with a microscope, etc., calculating the area of the extracted region, and penetrating the calculated area into the target The area of the hole. For such measurement, for example, a digital microscope manufactured by Keyence Corporation and attached software can be used, but when these cannot be prepared, or when the area of the through hole is too large to fit in the field of view of the microscope Other photographing devices capable of storing image data and image processing software may be used. In addition, about the specific usage method of the digital microscope by Keyence, Inc. and attached software, the measuring method of the particle size of the porous particle as described in an Example can be referred.

The hole diameter of the through hole 21 is preferably smaller than the particle diameter of the porous particles contained in the porous particle layer 42. The hole diameter of the through hole 21 is preferably less than 10 mm, more preferably less than 8 mm. The lower limit of the hole diameter of the through hole 21 is not particularly limited, but is usually 0.8 mm or more, preferably 1.5 mm or more. The space | interval (distance between the centers of the through-holes 21) of the through-holes 21 is 1-20 mm normally, Preferably it is 1-6 mm. The number of through holes 21 per unit area of the top sheet 2 is usually 0.3 to 30 / cm ² , preferably 1 to 20 / cm ² . In the present embodiment, as shown in FIG. 3, the through holes 21 are arranged in a staggered manner, but the arrangement of the through holes 21 is not limited to this and can be changed as appropriate.

  The diameter of the through hole is measured as follows in consideration of the fact that the shape of the through hole is not necessarily a perfect circle. By extracting the through-hole region from the through-hole image by binarizing the image of the through-hole photographed with a microscope, etc., calculating the area of the extracted region, and penetrating the calculated area into the target The area of the hole. Under the assumption that the target through-hole is a circle, the diameter of the circle is calculated based on the area of the target through-hole, and the calculated diameter is set as the hole diameter of the target through-hole. For such measurement, for example, a digital microscope manufactured by Keyence Corporation and attached software can be used, but when these cannot be prepared, or when the area of the through hole is too large to fit in the field of view of the microscope Other photographing devices capable of storing image data and image processing software may be used. In addition, about the specific usage method of the digital microscope by Keyence, Inc. and attached software, the measuring method of the particle size of the porous particle as described in an Example can be referred.

  Examples of the top sheet 2 include non-woven fabrics, woven fabrics, and synthetic resin films in which through-holes are formed, and preferred are non-woven fabrics in which through-holes are formed. The opening process for forming the through hole can be performed according to a conventional method.

  Examples of the nonwoven fabric include an air-through nonwoven fabric, a spunbond nonwoven fabric, a point bond nonwoven fabric, a spunlace nonwoven fabric, a needle punched nonwoven fabric, a melt blown nonwoven fabric, and a combination thereof (for example, SMS).

  Examples of the fibers constituting the nonwoven fabric include natural fibers (wool, cotton, etc.), recycled fibers (rayon, acetate, etc.), inorganic fibers (glass fibers, carbon fibers, etc.), synthetic resin fibers (polyethylene, polypropylene, polybutylene, ethylene). -Polyolefin such as vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ionomer resin; polyester such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polylactic acid; And polyamides such as nylon). Examples of the form of the fibers constituting the nonwoven fabric include core / sheath fibers, side-by-side fibers, island / sea fibers, etc .; hollow fibers; flat, Y-shaped, C-shaped, etc. Atypical fiber; three-dimensional crimp fiber of latent crimp or actual crimp; split fiber divided by physical load such as water flow, heat, embossing and the like.

  Examples of the nonwoven fabric manufacturing method include a method of forming a web (fleece) and physically and chemically bonding fibers. Examples of the web forming method include a spunbond method and a dry method (card). Method, spunbond method, melt blown method, airlaid method, etc.), wet method, etc., and examples of the bonding method include thermal bond method, chemical bond method, needle punch method, stitch bond method, spunlace method, etc. It is done.

  The thickness, basis weight, density, and the like of the top sheet 2 can be appropriately adjusted as long as the user's liquid excrement can permeate. When using a non-woven fabric as the top sheet 2, the fineness, fiber length, density, basis weight, thickness, etc. of the non-woven fabric can be appropriately adjusted from the viewpoints of permeability of liquid excrement, touch, and the like. . From the viewpoint of improving the concealability of the top sheet 2, the nonwoven fabric used as the top sheet 2 may contain an inorganic filler such as titanium oxide, barium sulfate, or calcium carbonate.

<Back sheet>
The back sheet 3 is an example of a liquid impermeable layer.
As shown in FIGS. 1 to 3, the back sheet 3 constitutes the clothing side surface of the diaper 1.
The back sheet 3 is a liquid impervious sheet that can prevent leakage of liquid excrement held by the absorber 4. Examples of the back sheet 3 include waterproof nonwoven fabric (for example, point bond nonwoven fabric, spun bond nonwoven fabric, spun lace nonwoven fabric, etc.), synthetic resin (for example, polyethylene, polypropylene, polyethylene terephthalate, etc.) film, nonwoven fabric and synthetic resin. Examples include a composite sheet with a film.

  The material, thickness, basis weight, density, and the like of the backsheet 3 can be adjusted as appropriate within a range in which leakage of the liquid excrement retained in the absorber 4 can be prevented. The back sheet 3 preferably has air permeability or moisture permeability in addition to liquid impermeability in order to reduce stuffiness when worn.

<Absorber>
As shown in FIG. 2, the absorber 4 is disposed so as to reach the rear surface portion 13 from the front surface portion 11 through the intermediate portion 12.

  As shown in FIGS. 3 and 4, the absorbent body 4 has an absorbent core 41 containing a superabsorbent polymer material and a porous particle layer 42 provided on the topsheet 2 side of the absorbent core 41. In addition, the porous particle layer 42 is provided between the top sheet 2 and the back sheet 3 so as to be positioned between the top sheet 2 and the absorbent core 41. Therefore, the liquid excrement that has permeated the top sheet 2 moves to the absorbent core 41 through the porous particle layer 42. At this time, the liquid excreta diffuses through the porous particle layer 42 and is temporarily stored in the porous particle layer 42. That is, the porous particle layer 42 functions as a storage layer (liquid excretion capturing layer) that temporarily stores liquid excretion that has passed through the top sheet 2. When the liquid excrement is temporarily stored in the porous particle layer 42, the voids between the porous particles and the voids in the porous particles function as a flow path for the liquid excrement, and the liquid excrement is the porous particle layer. 42 is diffused. For this reason, the liquid excreta can be efficiently transferred from the porous particle layer 42 to the absorbent core 41. The term “temporarily stored” means that the liquid excretion that has permeated the top sheet 2 is temporarily absorbed and retained by the porous particle layer 42, but then absorbs from the porous particle layer 42. It moves to the core 41 and is finally used with the intention of being absorbed and held by the absorbent core 41. However, all of the liquid excreta stored in the porous particle layer 42 does not move from the porous particle layer 42 to the absorbent core 41 but partially remains in the porous particle layer 42.

  As shown in FIG. 4, the absorbent core 41 includes a superabsorbent polymer (SAP) material layer 411 and a core wrap 412 that covers the superabsorbent polymer material layer 411. In FIG. 3, the core wrap 412 is omitted for simplification of the drawing.

Examples of the superabsorbent polymer material contained in the superabsorbent polymer material layer 411 include starch-based, cellulose-based, and synthetic polymer-based superabsorbent polymer materials. Examples of starch-based or cellulose-based superabsorbent polymer materials include starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, and crosslinked products of sodium carboxymethyl cellulose. Examples of polymer superabsorbent polymer materials include polyacrylates, polysulfonates, maleic anhydrides, polyacrylamides, polyvinyl alcohols, polyethylene oxides, polyaspartates, polyglutamic acids. Examples of the superabsorbent polymer materials such as salt-based, polyalginate-based, starch-based, and cellulose-based materials include polyacrylate-based (particularly sodium polyacrylate-based) superabsorbent polymer materials. . The basis weight of the superabsorbent polymer material is usually 20 to 400 g / m ² , preferably 50 to 300 g / m ² . Examples of the shape of the superabsorbent polymer material include a particulate shape, a fibrous shape, and a scaly shape. In the case of a particulate shape, the particle size is usually 200 to 1000 μm, preferably 250 to 750 μm. In addition, a particle size here is a particle size at the time of measuring based on the screening test method of JISR6002: 1998.

  The superabsorbent polymer material layer 411 may contain an absorbent material other than the superabsorbent polymer material. Examples of absorbent materials other than the superabsorbent polymer material include hydrophilic fibers, and examples of hydrophilic fibers include wood pulp obtained from coniferous or hardwood as a raw material (for example, groundwood pulp, refiner ground pulp, Mechanical pulp such as thermomechanical pulp and chemi-thermomechanical pulp; chemical pulp such as kraft pulp, sulfide pulp and alkali pulp; semi-chemical pulp); mercerized pulp or crosslinked pulp obtained by chemical treatment of wood pulp; bagasse Non-wood pulp such as kenaf, bamboo, hemp, and cotton (for example, cotton linter); regenerated cellulose such as rayon and fibrillar rayon; semisynthetic cellulose such as acetate and triacetate, etc. Among these, the cost is low, Pulverized pulp is preferred because it is easy to mold. Arbitrariness. When the superabsorbent polymer material layer 411 contains an absorptive material other than the superabsorbent polymer material, the mass ratio of the superabsorbent polymer material and the other absorbent materials in the superabsorbent polymer material layer 411 (high absorption The content of the functional polymer material: the content of the other absorbent material) is usually 10:90 to 90:10, preferably 20:80 to 80:20.

  In addition to the absorbent material, the superabsorbent polymer material layer 411 includes an antioxidant, a light stabilizer, an ultraviolet absorber, a neutralizer, a nucleating agent, an epoxy stabilizer, a lubricant, an antibacterial agent, a flame retardant, and an antistatic agent. You may contain additives, such as an agent, a pigment, and a plasticizer, as needed. For example, the superabsorbent polymer material layer 411 exhibits functions such as deodorizing property, antibacterial property, and endothermic effect by containing silver, copper, zinc, silica, activated carbon, aluminosilicate compound, zeolite, and the like. Can do.

  The core wrap 412 is a liquid permeable sheet through which a user's liquid excrement can permeate. Examples of the core wrap 412 include a nonwoven fabric, a woven fabric, a synthetic resin film in which liquid permeation holes are formed, and a net-like sheet having a mesh. By covering with the core wrap 412, it is possible to prevent the superabsorbent polymer material layer 411 from collapsing, improve the cushioning property of the absorbent body 4, improve the concealability of the absorbent body 4, and reduce the rewet back of the absorbent body 4.

  In the present embodiment, the entire surface of the superabsorbent polymer material layer 411 is covered with the core wrap 412, but a part of the surface of the superabsorbent polymer material layer 411 may be covered with the core wrap 412. The core wrap 412 may be composed of one sheet or may be composed of a plurality of sheets.

The particle size of the porous particles contained in the porous particle layer 42 is 2 to 10 mm, and the number of porous particles per unit volume of the porous particle layer 42 is 2 to 40 particles / cm ³ .

  The particle size of the porous particles contained in the porous particle layer 42 can be appropriately adjusted within a range of 2 to 10 mm, preferably 3 to 10 mm, more preferably 3 to 8 mm.

  The measurement of the particle size of the porous particle is based on the point that the shape of the porous particle is not necessarily a perfect sphere, and the outer shape (outer surface) of the porous particle when the porous particle is a fiber lump. Considering the point that it is difficult to define, it is implemented as follows. By binarizing the image of the porous particles photographed with a microscope, the target porous particle region is extracted, the area of the extraction region is calculated, and the calculated porous region is the target porous particle Is the projected area. The same measurement is performed 10 times, and the average value A is obtained. Under the assumption that the porous particle is a perfect sphere, the diameter D (D = √ (4A / π)) of the circle is calculated based on the average value A of the projected area of the porous particle, and the calculated diameter Let D be the particle size of the porous particles. For such measurement, for example, a digital microscope manufactured by Keyence Corporation and attached software can be used. However, when these cannot be prepared, or when the porous particle size is large, it does not fall within the scope of the microscope. In this case, other photographing devices and image processing software capable of storing image data may be used. In addition, regarding the specific use method of the digital microscope by Keyence Corporation and the attached software, the column of the measuring method of the particle diameter of the porous particle as described in an Example can be referred.

The number of porous particles per unit volume of the porous particle layer 42 can be appropriately adjusted within a range of 2 to 40 particles / cm ³ , preferably 2 to 30 particles / cm ³ , more preferably 3 to 3. 20 / cm ³ .

The number (g / cm ³ ) of porous particles per unit volume of the porous particle layer is calculated based on the following equation.
N _V = D / W
In the formula, N _V is the number of porous particles per unit volume of the porous particle layer (number / cm ³ ), D is the density of the porous particle layer (g / cm ³ ), and W is the porous particle 1 It represents the mass (g) per piece.

The density (g / cm ³ ) of the porous particle layer is calculated based on the following formula.
D = B / T × 10 ⁻³
In the formula, D represents the density (g / cm ³ ) of the porous particle layer, B represents the basis weight (g / m ² ) of the porous particle layer, and T represents the thickness (mm) of the porous particle layer.

The basis weight (g / m ² ) of the porous particle layer is measured as follows. Five test pieces of a predetermined size (for example, 100 mm × 100 mm) are cut out from the portion of the absorbent body where the porous particle layer is present. The mass of each test piece is measured with a direct balance (for example, electronic balance HF-300 manufactured by Kensei Kogyo Co., Ltd.), and the average value of the five measured values is taken as the mass of the test piece before removing the porous particles. After removing the porous particles from each test piece, the mass of each test piece is measured in the same manner as described above, and the average value of the five measured values is taken as the mass of the test piece after removing the porous particles. By subtracting the mass of the test piece after removing the porous particles from the mass of the test piece before removing the porous particles, the content of the porous particles in the test piece before removing the porous particles is calculated. Based on the content of the porous particles in the test piece before removing the porous particles and the size of the test piece before removing the porous particles, the mass of the porous particles per unit area in the test piece before removing the porous particles ( g / m ² ) is calculated, and this is defined as the basis weight of the porous particle layer.

The thickness (mm) of the porous particle layer is measured as follows. Five test pieces of a predetermined size (for example, 100 mm × 100 mm) are cut out from the portion of the absorbent body where the porous particle layer is present. The thickness of each test piece at a measurement pressure of 5.0 gf / cm ² using a thickness gauge (Ozaki Mfg. Co., Ltd. dial thickness gauge large type JB, upper and lower gauge head φ50 mm, measurement pressure 5.0 gf / cm ² ). And the average of the five measured values is taken as the thickness of the test piece before removal of the porous particles. After removing the porous particles from each test piece, the thickness of each test piece is measured in the same manner as described above, and the average value of the five measured values is taken as the thickness of the test piece after removing the porous particles. By subtracting the thickness of the test piece after removing the porous particles from the thickness of the test piece before removing the porous particles, the thickness (mm) of the porous particle layer in the test piece before removing the porous particles is calculated. The thickness of the porous particle layer.

  The measurement of the mass (g) per porous particle is performed as follows. 50 porous particles are taken out from the absorber, the total mass is measured with an electronic balance, and the mass (g) per porous particle is calculated based on the measured value. The same measurement is performed 5 times, and the average value is defined as the mass per porous particle.

  The porous particles contained in the porous particle layer 42 are particles having a large number of pores (voids). Specific examples of the porous particles include fiber balls and porous cellulose particles. Among them, one kind can be used alone or two or more kinds can be used in combination.

  The porous particles preferably have hydrophilicity. By constituting the porous particles with a hydrophilic material, hydrophilicity can be imparted to the porous particles. Examples of the porous particles having hydrophilicity include fiber balls containing one or more fibers selected from hydrophilic fibers and hydrophilized hydrophobic fibers, and porous cellulose particles. The porous particles may contain a hydrophobic material as long as the hydrophilicity can be maintained. Due to the hydrophilicity of the porous particles, when the liquid excreta diffuses through the porous particle layer 42, the voids in the porous particles easily function as a flow path for the liquid excrement. Therefore, the porous particle layer 42 can effectively exhibit the function as a reservoir layer (liquid excrement capturing layer).

  The fiber ball is a spherical fiber lump and is a fiber form used for nail cotton such as bedding and stuffed animals. The intersection of the fibers in the fiber ball may be joined or not joined, but is preferably joined from the viewpoint of imparting compression resistance or compression repulsion to the fiber ball. Examples of the bonding mode include bonding using fiber heat-fusibility and bonding using a binder (binder fiber, adhesive, etc.). Decrease in the specific volume (porosity) of the porous particle layer 42 that may occur when the diaper 1 is used (for example, pressurization by the weight of the user) because the fiber ball has compression resistance or compression resilience. And a decrease in performance of the porous particle layer 42 associated therewith (for example, a decrease in the releasability of the stored liquid excretion to the absorbent core 41 caused by shortening the interfiber distance and increasing the capillary force) ) Can be prevented.

  As the fiber ball and the porous cellulose particles, those produced according to a conventional method may be used, or commercially available products may be used. As a manufacturing method of the fiber ball, for example, a method of granulating the fiber by heat-sealing or heat-shrinking (for example, JP-A Nos. 2000-345457 and 7-39659), a binder is used. Examples thereof include a granulating method (for example, JP-A-63-50373 and JP-A-11-105030). For example, Japanese Patent Laid-Open No. 2000-345457 discloses a fiber ball in which a heat-adhesive conjugate fiber having a thermoplastic elastomer as a heat-adhesive component and a polyester-based main fiber having a high dry heat shrinkability are thermally contracted while the main fiber is thermally contracted. The manufacturing method which shape | molds is disclosed. Japanese Patent Laid-Open No. 7-39659 discloses that a plurality of synthetic fiber crimped yarns are aligned and subjected to a converging process, then cut, and then heat treated at a temperature below the melting point of the synthetic fiber crimped yarn. Thus, a method for producing a fiber ball by expressing crimps of a processed yarn is disclosed. A commercially available fiber ball processing apparatus (for example, Ball Fibers Forming Machine CMM16 manufactured by Massias) can be used for manufacturing the fiber ball. Examples of the fiber ball manufactured using the fiber ball processing apparatus include a fiber ball obtained by processing fiber balls of thermoplastic resin fibers (for example, polyester fibers). In fiber ball processing of thermoplastic resin fibers, fiber intersections in the fiber ball are bonded (for example, bonded using the heat-fusibility of the fiber, and binder (binder fiber, adhesive, etc.) is used to resist the fiber ball. Compressibility or compression resilience can be imparted.

  Examples of the fiber constituting the fiber ball include a hydrophilic fiber, a hydrophobic fiber, or a mixture thereof. The fiber ball is one or more kinds selected from a hydrophilic fiber and a hydrophobic fiber subjected to a hydrophilic treatment. It is preferable that 2 or more types of fibers are included. Thereby, hydrophilicity can be imparted to the fiber ball. As long as the hydrophilicity can be maintained, the fiber ball may contain hydrophobic fibers. As a fiber ball containing a hydrophilic fiber, the fiber ball comprised by the 1 type, or 2 or more types of hydrophilic material selected from cotton, a pulp, and paper is mentioned, for example. Specifically, commercially available cotton balls, pulp particles obtained by granulating pulp powder with a tumbling granulator, paper lump obtained by cutting a paper string produced by rolling paper, and the like can be mentioned. .

  The hydrophilic fiber is not particularly limited as long as it has a hydrophilic group (for example, hydroxyl group, amino group, carboxyl group, amide group, etc.). Examples of hydrophilic fibers include wood pulp obtained from softwood or hardwood (for example, mechanical pulp such as groundwood pulp, refiner ground pulp, thermomechanical pulp, chemithermomechanical pulp; craft pulp, sulfide pulp, alkaline pulp, etc. Chemical pulp; semi-chemical pulp, etc.]; mercerized pulp or cross-linked pulp obtained by chemically treating wood pulp; non-wood pulp such as bagasse, kenaf, bamboo, hemp, cotton; Recycled fibers; Cellulosic semi-synthetic fibers such as acetate and triacetate; Other cellulosic fibers such as carboxymethyl cellulose fiber; Synthetic fibers such as acrylic fiber and vinylon.

  Examples of the hydrophobic fiber include polylactic acid fiber, polyester fiber, polyolefin fiber, and nylon fiber. Examples of the hydrophilic treatment of the hydrophobic fiber include a treatment using a surfactant, a hydrophilic agent, and the like. .

  When the porous particles are fiber balls or porous cellulose particles having a particle diameter of 2 to 10 mm, the mass per porous particle is preferably 3 to 35 mg, more preferably 3 to 30 mg. When the porous particles are fiber balls or porous cellulose particles having a particle diameter of 2 to 10 mm, and the mass per porous particle is 3 to 35 g, the porous particles have sufficient voids inside. Therefore, when the liquid excreta diffuses through the porous particle layer 42, the voids in the porous particles easily function as a flow path for the liquid excrement. Therefore, the porous particle layer 42 can effectively exhibit the function as a reservoir layer (liquid excrement capturing layer).

An adhesive (for example, a hot melt adhesive) is preferably applied to the interface between the porous particle layer 42 and the top sheet 2 and / or the interface between the porous particle layer 42 and the core wrap 412. Thereby, the porous particles contained in the porous particle layer 42 can be fixed. From the viewpoint of liquid permeability, the adhesive is preferably not applied to the entire interface, and is preferably applied in a pattern such as dots, spirals, and stripes. Examples of the method for applying the adhesive include spiral coating, coater coating, curtain coater coating, and summit gun coating. The coating amount (basis weight) of the adhesive is usually 3 to 100 g / m ² , preferably 5 to 50 g / m ² . As the adhesive, for example, styrene-ethylene-butadiene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS) or the like mainly composed of rubber or linear low density Pressure-sensitive adhesive or heat-sensitive adhesive mainly composed of olefin such as polyethylene; water-soluble polymer (for example, polyvinyl alcohol, carboxymethyl cellulose, gelatin, etc.) or water-swellable polymer (for example, polyvinyl acetate, polyacrylic acid) And water-sensitive adhesives such as sodium).

The thickness, basis weight, and the like of the porous particle layer 42 can be appropriately adjusted according to the characteristics that the diaper 1 should have (for example, absorbency, strength, lightness, etc.). The thickness of the porous particle layer 42 is usually 1 to 10 mm, preferably 2 to 6 mm, and the basis weight is usually 25 to 500 g / m ² , preferably 30 to 400 g / m ² . Note that the thickness, basis weight, and the like of the porous particle layer 42 may be constant throughout or may be partially different.

  In the absorbent body 4 according to the present embodiment, as shown in FIG. 4, the porous particle layer 42 is provided on the entire surface of the absorbent core 41 on the top sheet 2 side. It is not necessarily limited to these, and can be changed as appropriate.

Modification examples A to C of the absorbent body 4 in which the arrangement of the porous particle layer is changed are shown in FIGS.
In the absorbent body 4A according to the modified example A, as shown in FIG. 6, the porous particle layer 42A is a part of the region corresponding to the intermediate portion 12 of the diaper 1 on the topsheet 2 side surface of the absorbent core 41. Is provided. The portion where the porous particle layer 42 </ b> A is provided is a portion located on the rear surface portion 13 side of the diaper 1 in the region corresponding to the intermediate portion 12 of the diaper 1. The porous particle layer 42 </ b> A has a substantially rectangular first portion located on the rear surface portion 13 side of the diaper 1, and a first portion extending from the side edge of the first portion toward the center of the surface of the absorbent core 41 on the topsheet 2 side. And has two parts. The width of the second portion is gradually reduced toward the center of the surface of the absorbent core 41 on the top sheet 2 side. According to the modified example A, the spread of the liquid excretion excreted from the user can be prevented, and the liquid excretion can be efficiently transferred from the porous particle layer 42A to the absorbent core 41.

  In the absorbent body B according to the modified example B, as shown in FIG. 7, the porous particle layer 42 </ b> B is a part of the region corresponding to the intermediate portion 12 of the diaper 1 on the topsheet 2 side surface of the absorbent core 41. Is provided. The part in which the porous particle layer 42B is provided is a part located on the rear surface part 13 side of the diaper 1 from the center among both side edge parts extending in the longitudinal direction of the region corresponding to the intermediate part 12 of the diaper 1. . According to the modified example B, it is possible to prevent the liquid excretion excreted from the user from leaking beyond the leak-proof cuffs 7a and 7b described later. Therefore, the modified example B is particularly useful as a diaper for relatively older infants who can take a sideways posture and open and close legs.

  In the absorbent body C according to the modified example C, as shown in FIG. 8, the porous particle layer 42 </ b> C is a part of the region corresponding to the rear surface portion 13 of the diaper 1 in the surface of the absorbent core 41 on the topsheet 2 side. Is provided. According to the modified example C, the liquid excretion excreted from the user can be prevented from flowing toward the user's back. Therefore, the modified example C is particularly useful as a diaper for relatively young infants who often take a lying-down posture.

  As shown in FIGS. 1 to 3, the diaper 1 includes a liquid impervious cover sheet 6, a liquid impervious leak-proof cuff 7 a and 7 b, a liquid, in addition to the top sheet 2, the back sheet 3 and the absorber 4. An impermeable leak-proof sheet 8, elastic members 91, 92, 93, 94 and the like are provided. Hereinafter, these members will be described.

<Cover sheet>
As shown in FIGS. 1 to 3, a liquid-impermeable cover sheet 6 is provided on the skin side surface of the top sheet 2. As shown in FIGS. 1 to 3, an opening 61 is formed at substantially the center of the cover sheet 6, and a part of the top sheet 2 (a part of the arrangement region of the absorber 4) It is exposed from the opening 61 and constitutes the skin side surface of the diaper 1 together with the cover sheet 6.

  The cover sheet 6 is a liquid impermeable sheet, and examples of the liquid impermeable sheet include a waterproofed nonwoven fabric (for example, a point bond nonwoven fabric, a spunbond nonwoven fabric, a spunlace nonwoven fabric, etc.), a synthetic resin (for example, , Polyethylene, polypropylene, polyethylene terephthalate, etc.) film, a composite sheet of a nonwoven fabric and a synthetic resin film, and the like.

<Leak-proof cuff>
As shown in FIGS. 1 to 3, leakage prevention cuffs 7 a and 7 b made of a liquid impermeable sheet are provided on both sides of the opening 61 of the cover sheet 6. One end of each of the leak-proof cuffs 7 a and 7 b is a fixed end sandwiched between the top sheet 2 and the cover sheet 6, and the other end is exposed from the opening 61 of the cover sheet 6. The free end to do. Elastic portions 71a and 71b extending in the vertical direction Y are provided at the free ends of the leak-proof cuffs 7a and 7b, and the leak-proof cuffs 7a and 7b stand up toward the skin direction of the user.

<Leak-proof sheet>
As shown in FIGS. 2 and 3, a liquid-impermeable leak-proof sheet 8 is provided between the back sheet 3 and the absorber 4. The leak-proof sheet 8 is a liquid-impermeable sheet. Examples of the liquid-impermeable sheet include a waterproofed nonwoven fabric (for example, a point bond nonwoven fabric, a spunbond nonwoven fabric, a spunlace nonwoven fabric, etc.), a synthetic resin ( For example, polyethylene, polypropylene, polyethylene terephthalate, etc.) film, a composite sheet of a nonwoven fabric and a synthetic resin film, and the like can be mentioned.

<Elastic member>
As shown in FIGS. 1 to 3, elastic members 91, 92, 93, and 94 are provided between the back sheet 3 and the cover sheet 6 that are hourglass shapes having substantially the same dimensions. In FIG. 1, some of the elastic members 91, 92, 93, and 94 are omitted.

  As shown in FIG. 1, a waist gather is formed in the waist opening by the elastic contraction force of the elastic members 91 and 92, and a leg gather (leg) is formed in the leg opening by the elastic contraction force of the elastic members 93 and 94. Side cuff) is formed. Leakage of liquid excretion from the leg opening is prevented by the leg gathers.

  As the elastic members 91 and 92, for example, a strand-like or string-like elastic body having a thickness of about 310 to 940 dtex can be used. As the elastic members 93 and 94, for example, a strand having a thickness of about 470 to 940 dtex can be used. A string-like or string-like elastic body can be used. As the elastic members 91, 92, 93, 94, elastic fiber nonwoven fabrics having elasticity or the like may be used.

  As shown in FIGS. 2 and 3, the elastic members 91 and 92 are attached to the front surface portion 11 and the rear surface portion 13 such that the elastic members 91 and 92 can be contracted in the expanded state in the lateral direction X and separated in the longitudinal direction Y. ing. As shown in FIGS. 2 and 3, the elastic member 93 includes portions 93 a and 93 b extending along both side portions 121 a and 121 b of the intermediate portion 12, and a portion 93 c extending in the lateral direction X and connecting the portions 93 a and 93 b. have. 2 and 3, the elastic member 94 includes portions 94a and 94b extending along both side portions 121a and 121b of the intermediate portion 12, and a portion 94c extending in the lateral direction X and connecting the portions 94a and 94b. have. Since the absorbent body 4 extends from the front surface portion 11 to the rear surface portion 13 through the intermediate portion 12, the absorbent body 4 is pressed against the skin side of the user by the contraction force of the elastic members 91, 92, 93, 94. Leakage of liquid excrement for the user is prevented.

  The diaper 1 is worn so that the top sheet 2 and the cover sheet 6 are located on the inner side (user's skin side) and the back sheet 3 is located on the outer side (user's clothing side). However, it is not necessary for the user to wear clothes. The liquid excrement of the user penetrates into the absorbent body 4 through the top sheet 2 exposed from the opening 61 of the cover sheet 6 and is absorbed and held by the absorbent body 4. Leakage of the liquid excretion absorbed and held by the absorber 4 is prevented by the back sheet 3 and the leak-proof sheet 6. Examples of liquid excreta to be absorbed include watery stool, urine, menstrual blood, and downstream products, but are usually watery stool and urine.

In the diaper 1, when liquid excrement moves from the porous particle layer 42 to the absorbent core 41, among the components of the liquid excretion, moisture easily moves from the porous particle layer 42 to the absorbent core 41. Solid content such as quality is easily captured by the porous particle layer 42. Therefore, the movement of the liquid excrement remaining in the porous particle layer 42 as a fluid is slowed, thereby preventing the liquid excretion from exuding (rewetting back) from the porous particle layer 42 to the top sheet 2. Can do. Such an effect of preventing re-wetting back of liquid excrement by the porous particle layer 42 includes the range of the particle size (mm) and density (pieces / cm ³ ) of the porous particles contained in the porous particle layer 42, and It changes significantly based on the presence or absence of the through-hole 21 formed in the top sheet 2.

That is, the effect of preventing rewet back of high-viscosity liquid excrement (for example, watery stool, menstrual blood, etc.) having a high solid content such as fibrous material is that the particle size of the porous particles is less than 2 mm, and the porous The particle diameter of the porous particles is 2 mm or more and the density of the porous particles is 40 particles / cm ³ or less than the case where the density of the porous particles exceeds 40 particles / cm ³ (see Comparative Example 4). The case (see Examples 1-6) is significantly higher. Similarly, the effect of preventing rewetting back of low-viscosity liquid excrement (for example, urine) having a low solid content such as fiber is higher in the latter than in the former.

Further, the effect of preventing rewet back on high-viscosity liquid excrement is when the particle size of the porous particles exceeds 10 mm and the density of the porous particles is less than 2 particles / cm ³ (see Comparative Example 3), There is no significant difference between the case where the particle size of the porous particles is 10 mm or less and the density of the porous particles is 2 particles / cm ³ or more (see Examples 1 to 6). However, the effect of preventing rewet back on low-viscosity liquid excrement is significantly higher in the latter than in the former.

  Moreover, when the particle size and density of the porous particles are about the same, but the two cases where the presence or absence of the through-holes 21 formed in the top sheet 2 are different (see Example 1 and Comparative Example 5), the viscosity is high. The effect of preventing rewet back on liquid excrement is greater when the through hole 21 is formed in the top sheet 2 than when the through hole 21 is not formed in the top sheet 2 (see Comparative Example 5) (see Example 1). ) Is significantly higher. In addition, although the rewet back prevention effect with respect to low-viscosity liquid excrement generally shows a downward tendency by forming the through-hole 21 in the top sheet 2, it penetrates into the top sheet 2 when the porous particle layer 42 exists. Even if the holes 21 are formed, such a downward tendency is not observed.

As described above, the effect of preventing rewet back of liquid excrement by the porous particle layer 42 is in the range of the particle size (mm) and density (pieces / cm ³ ) of the porous particles contained in the porous particle layer 42, and It changes significantly based on the presence or absence of the through-hole 21 formed in the top sheet 2. Considering this, in the diaper 1, the through-hole 21 is formed in the top sheet 2, the particle diameter of the porous particles is 2 to 10 mm, and the density of the porous particles is 2 to 40 / It is adjusted to cm ³ . Therefore, according to the diaper 1, even if the liquid excrement has a high viscosity or a low viscosity, the liquid excretion can be effectively exuded (rewet back) from the porous particle layer 42 to the top sheet 2. Can be prevented. Therefore, the diaper 1 is particularly useful as an infant diaper that absorbs not only low-viscosity liquid excrement (eg, urine) but also high-viscosity liquid excrement (eg, watery stool).

Hereinafter, based on FIG. 5, one Embodiment of the manufacturing method of the absorber of this invention is described.
[First step]
The first step is a step of forming the superabsorbent polymer material layer 411. As shown in FIG. 5, the superabsorbent polymer material layer 411 is formed using a suction drum 110 that rotates in the transport direction MD and an absorbent material supply unit 120 that includes a hood that covers the suction drum 110. . On the peripheral surface 111 of the suction drum 110, concave portions 112 are formed at a required pitch in the circumferential direction as a mold for filling the absorbent material. When the suction drum 110 rotates and the recess 112 enters the absorbent material supply unit 120, the suction unit 113 acts on the recess 112, and the absorbent material supplied from the absorbent material supply unit 120 is vacuum sucked into the recess 112. The The absorptive material supplied from the absorptive material supply unit 120 includes a predetermined mass of hydrophilic fibers F supplied from a pulverizer (not shown) and superabsorbent polymer particles P supplied from the particle supply unit 121. Contains in a mixing ratio. Thus, the superabsorbent polymer material layer 411 is formed in the recess 112. The superabsorbent polymer material layer 411 contains hydrophilic fibers F and superabsorbent polymer particles P in a mixed state. The superabsorbent polymer material layer 411 formed in the recess 112 is transferred onto the lower core wrap 91 that proceeds toward the transport direction MD by the action of the transfer suction portion 150. A hot melt adhesive is applied to the upper surface of the lower core wrap 91, and the superabsorbent polymer material layer 411 is bonded onto the lower core wrap 91 with the hot melt adhesive. The superabsorbent polymer material layer 411 transferred to the lower core wrap 91 travels in the transport direction MD.

[Second step]
The second step is a step of laminating the upper core wrap 92 on the superabsorbent polymer material layer 411 that proceeds in the transport direction MD. A hot melt adhesive is applied to the lower surface of the upper core wrap 92, and the superabsorbent polymer material layer 411 is joined to the upper core wrap 92 by the hot melt adhesive. In this way, a continuous body of a laminate in which the upper layer core wrap 92, the superabsorbent polymer material layer 411, and the lower layer core wrap 91 are sequentially laminated is formed. The continuous body is cut into a predetermined shape by a pair of rolls 300 and 301, and an absorbent core 41 having a superabsorbent polymer material layer 411 and a core wrap 412 covering the superabsorbent polymer material layer 411 is formed. The

[Third step]
The third step is a step of applying an adhesive on the absorbent core 41. As shown in FIG. 5, an adhesive application device 302 is used for applying the adhesive. The adhesive application device 302 applies the adhesive in a pattern of dots, spirals, stripes, and the like by a method such as spiral coating, coater coating, curtain coater coating, summit gun coating, or the like. The adhesive is preferably a hot melt adhesive. Examples of the hot melt adhesive include styrene-ethylene-butadiene-styrene (SEBS), styrene-butadiene-styrene (SBS), and styrene-isoprene-styrene (SIS). Pressure-sensitive adhesives or heat-sensitive adhesives mainly composed of rubbers such as linear olefins such as linear low density polyethylene; water-soluble polymers (eg, polyvinyl alcohol, carboxymethylcellulose, gelatin, etc.) Or the water sensitive adhesives which consist of water swelling polymers (for example, polyvinyl acetate, sodium polyacrylate, etc.) are mentioned.

[Fourth step]
The fourth step is a step of supplying porous particles to the adhesive-coated surface of the absorbent core 41 to form a porous particle layer. As shown in FIG. 5, a porous particle supply device 303 is used for supplying the porous particles.

  The absorbent body 4 having the absorbent core 41 and the porous particle layer 42 laminated on one surface of the absorbent core 41 is manufactured through the first to fourth steps. Manufacture of the diaper 1 using the absorber 4 can be implemented according to a conventional method.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, the scope of the present invention is not limited to an Example.

<Example 1>
(1) Top sheet In this example, an apertured nonwoven fabric was used as the top sheet. Production of the apertured nonwoven fabric was performed as follows.
[Nonwoven fabric]
Core-sheath composite fiber (core-sheath ratio 50:50 (cross-sectional area ratio)), fineness 2.2 dtex, fiber length 51 mm, with polyethylene terephthalate (PET) as the core component and general high-density polyethylene (HDPE) as the sheath component ) Was subjected to carding treatment to produce a fibrous web (basis weight 25 g / m ² ). This fiber web was subjected to a general air-through bonding process to produce an air-through nonwoven fabric (thickness: 1.0 mm). In the air-through bonding process, the hot air temperature was set to 135 ° C., the air volume was set to 1 m / second, and the processing time was set to 10 seconds. These conditions (basis weight, air volume, treatment time, etc.) are set so that the thickness of the nonwoven fabric is 1.0 mm.

[Opening of non-woven fabric]
Through-holes were formed in the air-through nonwoven fabric using a pair of upper and lower molds composed of an upper mold in which a plurality of pins are arranged and a lower mold in which a plurality of holes are arranged. In the hole forming using a mold, through holes are formed in the air-through nonwoven fabric sandwiched between the upper mold and the lower mold by inserting each pin of the upper mold into each hole of the lower mold. During the hole forming, the mold temperature was set to 90 ° C., and the treatment time was set to 3 seconds.
The diameter and arrangement of the through holes formed in the nonwoven fabric can be adjusted by the thickness and arrangement of the upper pins, respectively. In this example, the pin diameter was set to φ5.0 mm, the pin tip angle was set to 45 degrees, the pin pitch was set to 7.0 mm, and the pin arrangement was set to 60 degrees staggered arrangement.

(2) Absorber [porous particles]
In this example, fiber balls were used as the porous particles constituting the porous particle layer. The fiber ball was manufactured by processing a polyester fiber (fineness: 6.6 dtex, fiber length: 32 mm) with a fiber ball processing apparatus (Ball Fibers Forming Machine CMM16 manufactured by Massias). At this time, the processing time in the fiber ball processing apparatus was set to 1 minute.

[Absorbent core]
Ground pulp obtained by grinding fluff pulp (fluff pulp "Supersoft" manufactured by International Paper Co., Ltd.) with a saw mill (manufactured by Ruiko Co., Ltd.) and superabsorbent polymer particles (superabsorbent manufactured by Sumitomo Seika Co., Ltd.) Polymer particles SA50) are mixed so that they are uniformly dispersed and then laminated, and the length is 150 mm, the width is 120 mm, the basis weight of the pulverized pulp is 250 g / m ² ± 3%, and the superabsorbent polymer particles An absorbent core having a basis weight of 250 g / m ² ± 3% was produced. The absorbent core thus manufactured was sandwiched between two tissues (core wraps) coated with a hot melt adhesive on the surface on the side of the absorbent core, and then pressure-molded to a thickness of 3.0 mm with a pressure device. .

[Absorber]
The fiber ball was laminated on the absorbent core covered with the core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.

(3) Measuring method The measuring method implemented by the present Example is as follows.
[Particle size of porous particles (mm)]
The measurement of the particle size of the porous particle is based on the point that the shape of the porous particle is not necessarily a perfect sphere, and the outer shape (outer surface) of the porous particle when the porous particle is a fiber lump. Considering the point that it is difficult to define, it was carried out as follows.
By binarizing the image of the porous particles taken with a microscope, etc., the target porous particle region is extracted, the area of the extracted region is calculated, and the calculated area is the projected area of the porous particle It was. The same measurement was performed 10 times, and the average value A was obtained. Under the assumption that the porous particle is a perfect sphere (that is, the projected area of the porous particle is a circle), the diameter D of the circle (D = √) based on the average value A of the projected area of the porous particle (4A / π)) was calculated, and the calculated diameter D was taken as the particle size of the porous particles. In addition, the image of the porous particle before and behind binarization is shown in FIG.
Specifically, it was carried out as follows using a digital microscope (controller: VHX-2000, zoom lens: X20 to X200) manufactured by Keyence Corporation and attached software.
(A) Initial adjustment was performed, and the lens magnification was set to a magnification at which the target particles entered the screen.
(B) The photographing conditions (standard photographing size, image size 1600 × 1200) were adjusted.
(C) The background was black and the target particles were set on the measurement table.
(D) Once the image was saved and recalled, “Measurement”, “Automatic Area Measurement”, “Luminance”, and “Start Measurement” were selected.
(E) The binarization threshold value was adjusted, and it was confirmed that the particle size and the size of the extraction region matched. At this time, particles may be removed as necessary, and unnecessary extraction regions may be removed.
(F) The area of the extraction region was calculated and recorded.
(G) The same measurement was performed 10 times, and the average value A of the projected areas of the porous particles was determined.
(H) Under the assumption that the porous particle is a perfect sphere (that is, the projected area of the porous particle is a circle), the circle calculated based on the average value A of the projected area of the porous particle The diameter D (D = √ (4A / π)) was taken as the particle size of the porous particles.
In this example, a digital microscope manufactured by Keyence Corporation and attached software were used, but when these cannot be prepared, or when the porous particle size is too large to fit in the field of view of the microscope, Other imaging devices that can store data (for example, imaging devices with low magnification) and image processing software may be used.

[Thickness of porous particle layer (mm)]
The thickness of the porous particle layer was measured as follows.
(A) Hard polyvinyl chloride through a double-sided tape on the lower gauge of the thickness gauge (Ozaki Mfg. Co., Ltd. dial thickness gauge large type JB, vertical gauge φ50mm, measurement pressure 5.0gf / cm ² ) A plate (length 150 mm × width 100 mm × thickness 3.0 mm) was attached.
(B) The gauge when the thickness gauge is in a horizontal state, the upper gauge head is gently moved up and down three times, and then the upper gauge head is placed on the rigid polyvinyl chloride plate attached to the lower gauge head. Set to “0”.
(C) Fiber balls were laminated on a rigid polyvinyl chloride plate in the same manner as in the production of the absorber to form a rectangular porous particle layer having a length of 100 mm and a width of 60 mm. The porous particle layer was formed at a position where the upper probe could be placed on the center of the porous particle layer.
(D) The upper gauge head was gently moved up and down three times, then placed on the porous particle layer, and the gauge was read in this state to measure the thickness of the porous particle layer.
(E) The same measurement was performed 5 times, and the average value was taken as the thickness of the porous particle layer.

[Basis weight of porous particle layer (g / m ² )]
The basis weight of the porous particle layer was measured as follows.
(A) A rigid polyvinyl chloride plate (length 150 mm × width 100 mm × thickness 3.0 mm) was attached to the electronic balance via a double-sided tape, and the mass in that state was adjusted to “0”.
(B) The fiber ball was laminated on the hard polyvinyl chloride plate in the same manner as in the production of the absorber to form a rectangular porous particle layer having a length of 100 mm and a width of 60 mm.
(C) The mass of the porous particle layer was measured with an electronic balance, and the mass per unit area (g / m ² ) was calculated based on the measured value. An electronic balance having a measurement digit number of 1/100 g or less was used. The same applies to other electronic balances used for mass measurement.
(D) The same measurement was performed 5 times, and the average value was taken as the basis weight of the porous particle layer.

[Mass (g) per porous particle]
The measurement of the mass per one porous particle was implemented as follows.
(A) The total mass of 50 particles was measured with an electronic balance, and the mass per particle was calculated based on the measured value.
(B) The same measurement was performed 5 times, and the average value was defined as the mass per particle.

[Density of porous particle layer (g / cm ³ )]
The density of the porous particle layer was calculated based on the following formula.
D = B / T × 10 ⁻³
In the formula, D represents the density (g / cm ³ ) of the porous particle layer, B represents the basis weight (g / m ² ) of the porous particle layer, and T represents the thickness (mm) of the porous particle layer.

[Number of porous particles per unit area of porous particle layer (pieces / cm ² )]
The number of porous particles per unit area of the porous particle layer was calculated based on the following formula.
N _A = B / W × 10 ⁻⁴
In the formula, N _A is the number of porous particles per unit area of the porous particle layer (pieces / cm ² ), B is the basis weight (g / m ² ) of the porous particle layer, and W is the porous particles. It represents the mass (g) per piece.

[Number of porous particles per unit volume of porous particle layer (pieces / cm ³ )]
The number of porous particles per unit volume of the porous particle layer was calculated based on the following equation.
N _V = D / W
In the formula, N _V is the number of porous particles per unit volume of the porous particle layer (number / cm ³ ), D is the density of the porous particle layer (g / cm ³ ), and W is the porous particle 1 It represents the mass (g) per piece.

[Transition rate of artificial water-like flights]
The artificial water-like stool was manufactured as follows.
66 g of bentonite (bentonite “Bengel A” manufactured by Hojun Co., Ltd.), 134 g of powdered cellulose (powdered cellulose “KC Flock W-200” manufactured by Nippon Paper Industries Co., Ltd.) No. ") and 1800 g of ion-exchanged water are stirred until they are evenly dispersed using a mixer equipped with a flat beater (" Kitchen Aid KSM5 "manufactured by FMI Co., Ltd.). Manufactured.
The artificial water-like stool produced a viscosity change after the completion of stirring. Therefore, the artificial water-like stool was allowed to stand at room temperature for 24 hours after the stirring was completed, and then used for measurement. However, in the measurement, a sample with a standing time of 72 hours or less after the completion of stirring was used, and a sample with a standing time of more than 72 hours after the stirring was not used.
The measurement of the rate of transfer of artificial water-like stool was carried out as follows.
(A) Square-shaped artificial skin (artificial skin PBZ13001 manufactured by Ideatex Japan Co., Ltd.) was attached to a square columnar weight so as to cover the bottom surface (vertical 100 mm × horizontal 100 mm). The portion of the artificial skin that protrudes from the bottom surface of the weight was bent along the contour of the weight and attached to the side surface of the weight via a double-sided tape. Care was taken not to cause wrinkles on the part of the artificial skin that was affixed to the bottom of the weight. In addition, the mass of the weight was adjusted so that the mass of the weight after application of the artificial skin was within the range of 2000 g ± 20 g.
(B) The mass (A ₁ (g)) of the absorbent body before dropping artificial water-like stool was measured.
(C) The top sheet was cut into a size of 150 mm length × 120 mm width, and after measuring its mass (T ₁ (g)), it was placed on the absorber and lightly pressed.
(D) About 10 mL of artificial water-like stool was collected in a syringe, and its mass (S ₁ (g)) was measured.
(E) The syringe was placed above the top sheet so that the distance between the tip and the top sheet was 10 mm, and artificial water-like stool was dripped from the syringe to the top sheet at a dropping rate of 1 mL / second.
(F) measuring the syringe mass after dropping (S ₂ (g)), subtracting the syringe mass after dropping from the mass of the previous dropping syringe _{(S 1 (g)) (} S 2 (g)) Was used to calculate the mass (F (g)) of the artificial water-like stool dropped. In addition, the amount of artificial water-like stool collected in the syringe in step (d) was adjusted so that the mass (F (g)) of dripped artificial water-like stool was in the range of 9.7 g to 10.3 g. .
(G) The artificial skin affixed to the bottom surface of the weight was wiped with a wet tissue (a spunlace nonwoven fabric impregnated with ion exchange water of about 150% of its mass) and moistened a little, and then the artificial skin was affixed The mass of the weight (W ₁ (g)) was measured.
(H) Within 30 seconds after wiping with a wet tissue, and within 180 seconds after the start of dripping of artificial water-like stool, the weight with the artificial skin attached was gently placed on the top sheet.
(I) Ten seconds after being placed on the top sheet, the weight with the artificial skin attached was taken out and the mass (W ₂ (g)) was measured.
(J) After the top sheet was peeled from the absorber, the mass of the top sheet (T ₂ (g)) and the mass of the absorber (A ₂ (g)) were measured.
(K) The same measurement was performed 3 times, and the average value was calculated.
(L) Based on the following formula | equation, the transfer rate to an absorber, the transfer rate to a top sheet, and the transfer rate to artificial skin were computed.

Transfer rate to absorber (%) = (absorber mass after dropping (A ₂ (g)) − absorber mass before dropping (A ₁ (g))) / mass of artificial water-like stool dropped (F ( g)) x 100

Transition rate to top sheet (%) = (top sheet mass after dropping (T ₂ (g)) − top sheet mass before dropping (T ₁ (g))) / mass of dripped artificial water-like stool (F ( g)) x 100

Rate of transfer to artificial skin (%) = (weight after dropping (W ₂ (g)) − weight weight before dropping (W ₁ (g))) / mass of dropped artificial watery stool (F (g) ) × 100

[Rewet amount of artificial urine]
Artificial urine was produced as follows.
Artificial urine is obtained by adding 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate heptahydrate, 3 g of calcium chloride dihydrate and 1 g of pigment (blue No. 1) to 10 kg of ion-exchanged water and stirring well. Manufactured.
Measurement of the rewet amount of the artificial urine was performed as follows.
The top sheet was cut into a size having a length of 150 mm and a width of 120 mm, and its mass (T ₁ (g)) was measured, and then placed on the absorber and lightly pressed.
A cylinder (diameter 60 mm, weight 200 g) was placed in the center of the top sheet. The pipette was placed above the top sheet so that the distance between the tip and the top sheet was 10 mm, and artificial urine was dropped from the pipette to the top sheet at a dropping rate of 80 mL / 10 seconds. 5 minutes after the start of artificial urine dripping, filter paper (Advantech No. 2,100 mm × 100 mm) whose mass (A (g)) was measured in advance is placed on the top sheet so that the center of the filter paper coincides with the artificial urine dripping position. A weight (3.5 kg / 100 cm ² ) was placed thereon. 8 minutes after the start of dropping artificial urine (3 minutes after the weight was set), the weight was removed and the mass (B (g)) of the filter paper was measured. The amount of change in the mass of the filter paper (B (g) -A (g)) was calculated. The same measurement was repeated 5 times, and the average value was defined as the rewet amount.

<Example 2>
(1) Top sheet In the present Example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this example, fiber balls were used as the porous particles constituting the porous particle layer. In this example, a cotton ball (“cotton ball No. 3” manufactured by White Cross Co., Ltd.) was used as a fiber ball.
[Absorbent core]
In this example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
Cotton balls were laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measuring method In this example, various measuring methods were carried out in the same manner as in Example 1. In addition, the image of the porous particle before and behind binarization in the measurement of the particle size of the porous particle is shown in FIG.

<Example 3>
(1) Top sheet In the present Example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this example, porous cellulose particles (“Bisco Pearl AH-4050L” manufactured by Rengo Co., Ltd.) were used as the porous particles constituting the porous particle layer.
[Absorbent core]
In this example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
Porous cellulose particles were laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measuring method In this example, various measuring methods were carried out in the same manner as in Example 1. In addition, the image of the porous particle before and behind binarization in the measurement of the particle size of the porous particle is shown in FIG.

<Example 4>
(1) Top sheet In the present Example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this example, pulp particles were used as the porous particles constituting the porous particle layer. In this example, pulp particles were produced by the following steps.
(A) Hardwood pulp fibers for papermaking (cellulose purity of about 50%) were cut into about 1 cm square and stirred with a mixer with tap water to dissolve.
(B) Pressurized and dehydrated to adjust the moisture content (ratio of moisture content to pulp fiber mass) to about 200%, and then pulverize with a mixer.
(C) The obtained pulp powder was granulated with a tumbling granulator (Ladge mixer M-20 manufactured by Matsubo Co., Ltd.).
(D) The obtained pulp particles were dried with a hot air dryer. At this time, the drying temperature was set to 120 ° C., and the drying time was set to 180 minutes.
(E) After drying, the pulp particles were sieved. A sieve having a mesh opening of 5 mm was passed through a sieve having a mesh opening of 5 mm, and a sieve having a mesh opening of 3 mm was further used.
Note that the particle size of the pulp particles changes according to the pulp fiber length (that is, the longer the fiber, the larger the particle size, while the shorter the fiber, the smaller the particle size). By adjusting the time, rolling granulation time, etc., the particle size of the pulp particles can be adjusted. For example, the particle size can be increased by increasing the moisture content, while the particle size can be decreased by decreasing the moisture content.
[Absorbent core]
In this example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
Pulp particles were laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measuring method In this example, various measuring methods were carried out in the same manner as in Example 1.

<Example 5>
(1) Top sheet In the present Example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this example, pulp particles having a particle size smaller than that of Example 4 were used as the porous particles constituting the porous particle layer. In this example, pulp particles were produced by the following steps.
In the same manner as in Steps (a) to (d) of Example 4, after pulp particles were granulated and dried, first, a sieve having an opening of 3 mm was passed through, and a sieve having passed through a sieve having an opening of 3 mm was further opened. What passed through a 2 mm sieve and remained on the 2 mm sieve was used as pulp particles.
[Absorbent core]
In this example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
Pulp particles were laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measuring method In this example, various measuring methods were carried out in the same manner as in Example 1.

<Example 6>
(1) Top sheet In the present Example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this example, a paper lump was used as the porous particles constituting the porous particle layer. In this example, a paper lump was manufactured by the following steps.
Bleached kraft paper (basis weight 17 g / m ² , width 120 mm) was rolled to produce a paper string having a diameter of about 4 mm. A piece with a length of about 4 mm was cut out from this paper string and used as a paper block in this example.
[Absorbent core]
In this example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
The paper block was laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measuring method In this example, various measuring methods were carried out in the same manner as in Example 1.

<Comparative Example 1>
(1) Top sheet In this comparative example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [nonwoven fabric]
In this comparative example, a nonwoven fabric layer was used instead of the porous particle layer. The nonwoven fabric was manufactured by the following steps.
Core-sheath type composite fiber (core-sheath ratio 50:50 (cross-sectional area ratio)) having a core component of polyethylene terephthalate (PET) and a sheath component of general high-density polyethylene (HDPE), fineness 3.3 dtex, fiber length 51 mm ) Was subjected to carding treatment to produce a fibrous web (basis weight 120 g / m ² ). This fiber web was subjected to a general air-through bonding process to produce an air-through nonwoven fabric (thickness 5.0 mm). In the air-through bonding process, the hot air temperature was set to 135 ° C., the air volume was set to 1 m / second, and the processing time was set to 10 seconds. These conditions (basis weight, air volume, processing time, etc.) are set so that the nonwoven fabric has a thickness of 5.0 mm.
[Absorbent core]
In this comparative example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
The nonwoven fabric was laminated onto an absorbent core covered with a core wrap. Thus, an absorbent body having an absorbent core covered with a core wrap and a nonwoven fabric layer (reservoir layer) laminated thereon was manufactured.
(3) Measurement method In this comparative example, various measurement methods were carried out in the same manner as in Example 1. In addition, the thickness (mm) of the nonwoven fabric layer was measured as follows.
(A) Set the thickness gauge (Dial Thickness Gauge, manufactured by Ozaki Mfg. Co., Ltd., measuring surface φ44mm, measuring pressure 3g / cm ² ) horizontally, and gently move the upper probe up and down three times, then set the gauge to “0” Combined.
(B) A nonwoven fabric layer cut to a length of 100 mm and a width of 100 mm was placed on a table with the upper measuring element raised.
(C) The upper gauge head was gently moved up and down three times and then placed on the nonwoven fabric layer. In this state, the gauge was read to measure the thickness of the nonwoven fabric layer.
(D) The same measurement was performed 10 times, and the average value was defined as the thickness of the nonwoven fabric layer.

<Comparative Example 2>
(1) Top sheet In this comparative example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [nonwoven fabric]
In this comparative example, a laminate of four nonwoven fabrics was used instead of the porous particle layer. Each nonwoven fabric was manufactured by the following steps.
Core-sheath type composite fiber (core-sheath ratio 50:50 (cross-sectional area ratio)) having a core component of polyethylene terephthalate (PET) and a sheath component of general high-density polyethylene (HDPE), fineness 3.3 dtex, fiber length 51 mm ) To which a hydrophilic oil agent (composition: unknown) was attached was carded to produce a fiber web (basis weight 30 g / m ² ). This fiber web was subjected to a general air-through bonding process to produce an air-through nonwoven fabric (thickness: 1.3 mm). In the air-through bonding process, the hot air temperature was set to 135 ° C., the air volume was set to 1.2 m / second, and the processing time was set to 10 seconds. These conditions (basis weight, air volume, treatment time, etc.) are set so that the thickness of the nonwoven fabric is 1.3 mm.
[Absorbent core]
In this comparative example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
A laminate of four nonwoven fabrics was laminated on an absorbent core covered with a core wrap. Thus, an absorbent body having an absorbent core covered with a core wrap and a nonwoven fabric layer (reservoir layer) laminated thereon was manufactured.
(3) Measurement method In this comparative example, various measurement methods were carried out in the same manner as in Example 1. The thickness (mm) of the nonwoven fabric layer was measured in the same manner as in Comparative Example 1.

<Comparative Example 3>
(1) Top sheet In this comparative example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this comparative example, a cotton ball having a larger particle diameter than the cotton ball of Example 2 (“cotton ball No. 7” manufactured by White Cross Co., Ltd.) was used as the porous particle constituting the porous particle layer.
[Absorbent core]
In this comparative example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
Cotton balls were laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measurement method In this comparative example, various measurement methods were carried out in the same manner as in Example 1.

<Comparative Example 4>
(1) Top sheet In this comparative example, the apertured nonwoven fabric manufactured like Example 1 was used as a top sheet.
(2) Absorber [porous particles]
In this comparative example, pulp particles having a particle diameter smaller than that of Example 5 were used as the porous particles constituting the porous particle layer. In this comparative example, pulp particles were produced by the following steps.
In the same manner as in Steps (a) to (d) of Example 4, after pulp particles were granulated and dried, the particles were passed through a sieve having an opening of 2 mm, and passed through the sieve having an opening of 2 mm were used as pulp particles. .
[Absorbent core]
In this comparative example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
Pulp particles were laminated on an absorbent core covered with a core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measurement method In this comparative example, various measurement methods were carried out in the same manner as in Example 1.

<Comparative Example 5>
In this comparative example, a nonwoven fabric produced in the same manner as in Example 1 was used as a top sheet without forming through holes.
(2) Absorber [porous particles]
In this comparative example, a fiber ball manufactured in the same manner as in Example 1 was used as the porous particles constituting the porous particle layer.
[Absorbent core]
In this comparative example, an absorbent core produced in the same manner as in Example 1 was used.
[Absorber]
The fiber ball was laminated on the absorbent core covered with the core wrap to form a porous particle layer. The porous particle layer was formed to have a rectangular shape with a length of 100 mm and a width of 60 mm. Thus, an absorbent body having an absorbent core covered with a core wrap and a porous particle layer (reservoir layer) laminated thereon was manufactured.
(3) Measurement method In this comparative example, various measurement methods were carried out in the same manner as in Example 1.

  Tables 1 and 2 show the results of Examples 1 to 6 and Comparative Examples 1 to 5.

  As shown in Table 2, Examples 1 to 6 using a porous particle layer as a reservoir layer are more of an artificial water-like stool absorber than Comparative Examples 1 and 2 using a nonwoven fabric layer as a reservoir layer. The rate of transfer to the top sheet and artificial skin of the artificial watery stool was significantly small. Moreover, although the rewetting amount of artificial urine in Examples 1-6 was comparable or more than the rewetting amount of artificial urine in Comparative Examples 1 and 2, the rewetting amount of artificial urine in Examples 1-6 was sufficient. It was small. Therefore, by using a porous particle layer as a reservoir layer, it is possible to effectively exude liquid excretion (artificial watery stool and artificial urine in this embodiment) from the porous particle layer to the top sheet (rewet back). It became clear that it can be prevented. When liquid excrement moves from the porous particle layer to the absorbent core through the core wrap, among the components of the liquid excrement, moisture tends to move from the porous particle layer to the absorbent core through the core wrap, but the fiber etc. Since the solid content of the liquid is easily trapped by the porous particle layer, the movement of the liquid excrement remaining in the porous particle layer becomes slow, and this causes the liquid excrement to stain from the porous particle layer to the top sheet. It is thought that it is possible to effectively prevent the discharge (rewet back).

As shown in Table 2, the effect of preventing the rewet back of liquid excrement by the porous particle layer is the particle size (mm) and density (pieces / cm ³ ) of the porous particles contained in the porous particle layer. ) As well as the presence or absence of through-holes formed in the topsheet.

That is, the effect of preventing the rewet back of high-viscosity liquid excrement (in the present example, artificial water-like feces) having a high solid content such as fibrous material is that the particle size of the porous particles is less than 2 mm, and the porous than Comparative example 4 in which the density of the particles exceeds 40 / cm ^3, the particle size of the porous particles is not less 2mm or more, and examples 1-6 density of the porous particles is 40 / cm ³ or less Was significantly higher. Similarly, the effect of preventing the rewet back of the low-viscosity liquid excrement (artificial urine in this example) having a low solid content such as fiber was higher in Examples 1 to 6 than in Comparative Example 4.

Further, the effect of preventing the rewet back of the high-viscosity liquid excrement (artificial water-like feces in this embodiment) is that the particle size of the porous particles exceeds 10 mm and the density of the porous particles is less than 2 particles / cm ³ . There was no significant difference between a comparative example 3 and Examples 1 to 6 in which the particle size of the porous particles was 10 mm or less and the density of the porous particles was 2 particles / cm ³ or more. However, the rewet back preventing effect of the low-viscosity liquid excrement (artificial urine in this example) was significantly higher in Examples 1 to 6 than in Comparative Example 3.

  Moreover, although the particle size and density of porous particles are comparable, when comparing Example 1 and Comparative Example 5 in which the presence or absence of through-holes formed in the top sheet is different, high-viscosity liquid excreta (in this example) The effect of preventing the rewet back of the artificial water-like stool was significantly higher in Example 1 in which the through holes were formed in the top sheet than in Comparative Example 5 in which the through holes were not formed in the top sheet. In addition, the rewetting back prevention effect of low-viscosity liquid excrement generally shows a tendency to decrease by forming a through hole in the top sheet. However, when a porous particle layer is used as a storage layer, the through hole is formed in the top sheet. Such a tendency to decrease was not observed even when formed.

From these results, when a porous particle layer is used as the reservoir layer, a through hole is formed in the top sheet, the particle size of the porous particle is 2 to 10 mm, and the density of the porous particle is 2 to 40 It was clarified that the rewetting back of the liquid excretion remaining in the porous particle layer can be effectively prevented by setting the number of particles / cm ³ , regardless of whether the liquid excrement has high viscosity or low viscosity. .

1 Disposable diaper (absorbent article)
2 Top sheet (liquid permeable layer)
21 Through hole 3 Back sheet (liquid impervious layer)
4 Absorber 41 Absorbent Core 42 Porous Particle Layer

Claims (8)

An absorbent article comprising a liquid permeable layer, a liquid impermeable layer, and an absorbent provided between the liquid permeable layer and the liquid impermeable layer,
The liquid permeable layer has a through hole penetrating the liquid permeable layer in a thickness direction,
The absorber has an absorbent core containing a superabsorbent polymer material, and a porous particle layer provided on the liquid permeable layer side of the absorbent core,
The particle size of the porous particles contained in the porous particle layer is 2 to 10 mm,
The absorbent article, wherein the number of porous particles per unit volume of the porous particle layer is 2 to 40 particles / cm ³ .   The absorptive article according to claim 1 in which said porous particles are 1 type, or 2 or more types of particles chosen from fiber ball and porous cellulose particles.   The absorptive article according to claim 2 in which said fiber ball contains 1 type, or 2 or more types of fibers chosen from hydrophilic fiber and hydrophobic fiber hydrophilized.   The absorbent article according to claim 3, wherein the fiber ball is made of one or more hydrophilic materials selected from cotton, pulp, and paper.   The absorptive article according to any one of claims 2 to 4 whose mass per piece of said porous particles is 3-35 mg.   The absorbent article of any one of Claims 1-5 whose hole diameter of the said through-hole is less than 10 mm.   The absorptive article according to any one of claims 1 to 6 in which said penetration hole is formed so that the opening rate of said liquid permeability layer may be 5 to 90%.   The absorbent article according to any one of claims 1 to 7, wherein the porous particle layer, the liquid permeable layer, and / or the absorbent core are bonded with an adhesive.