CN110072500B

CN110072500B - Absorbent body and method for producing same

Info

Publication number: CN110072500B
Application number: CN201780077046.5A
Authority: CN
Inventors: 远藤阳一; 磯和树; 上野智志
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2016-12-20
Filing date: 2017-12-11
Publication date: 2021-07-23
Anticipated expiration: 2037-12-11
Also published as: TWI700077B; WO2018116893A1; CN110072500A; TW201828898A

Abstract

The absorbent body (16) of the present invention has a substrate sheet (12) and an absorbent core (14). The absorbent core (14) contains a water-absorbent resin, a non-fibrous water-soluble polymer, and a polyhydric alcohol. The content of the water-absorbent resin is 40 to 95 mass% with respect to the absorbent core. The content of the non-fibrous water-soluble polymer is 0.1 to 5 mass% based on the water-absorbent resin. The content of the polyhydric alcohol is 300 to 1500 mass% with respect to the non-fibrous water-soluble polymer. The non-fibrous water-soluble polymer is preferably at least 1 selected from the group consisting of polyvinylpyrrolidone, polyvinyl butyral, and dextrin. The polyhydric alcohol is also preferably 1 or more selected from glycerol, propylene glycol and polyethylene glycol.

Description

Absorbent body and method for producing same

Technical Field

The present invention relates to an absorbent body. The absorbent body of the present invention is suitable as an absorbent body for an absorbent article. The present invention also relates to a method for producing an absorbent body.

Background

As an absorbent material of an absorbent article, a stacked body of water-absorbent fibers such as pulp, a stacked body of a mixture of the water-absorbent fibers and particles of a super-absorbent polymer, or the like is widely used. Since an absorber including these materials is relatively bulky, an absorber aimed at reduction in thickness and size has been proposed. Examples of such an absorbent body include: a structure in which a high-absorbent polymer and a fibrous binder are dispersed in a liquid, and the dispersion is applied to a sheet-like substrate (see patent documents 1 to 3).

Patent document 1 describes a composite composition containing a cellulose-derived microfibril having a hydratable property and water-swellable solid particles bonded to each other with the microfibril. Patent document 2 describes a water-absorbent composite sheet comprising: a composite comprising a particulate SAP and a fibrous binder, and a sheet-like substrate supporting the composite. The composite contains inorganic powders such as alumina, silica, zeolite, bentonite, and kaolin. Patent document 3 describes a multifunctional sheet-like absorbent body including: an absorbent layer containing a super absorbent resin; a nonwoven fabric-like substrate on which a super absorbent resin is supported; and a binder component for binding the super absorbent resins to each other and to the base material.

Patent document 4 discloses an absorbent material having a porous sponge structure, which is composed of a highly water-absorbent polymer, fibers, and an alkylene oxide polymer. Patent document 5 describes a liquid-absorbing sheet in which a sheet-like liquid-absorbing layer is formed of a super absorbent resin, a filter aid, fibers, and an alkylene oxide-based polymer. As the filter aid, diatomaceous earth, activated carbon, talc, perlite, and the like are used.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. Hei 10-168230

Patent document 2: japanese patent laid-open No. 9-299399

Patent document 3: japanese patent laid-open No. 2000-201975

Patent document 4: international publication No. 94/07599 booklet

Patent document 5: japanese patent laid-open No. 8-80318

Disclosure of Invention

The invention provides an absorber, which comprises a base material sheet and an absorbent core arranged on the base material sheet. The absorbent core contains a water-absorbent resin, a non-fibrous water-soluble polymer, and a polyhydric alcohol. The content of the water-absorbent resin is 40 to 95 mass% with respect to the absorbent core, and the content of the non-fibrous water-soluble polymer is 0.1 to 5 mass% with respect to the water-absorbent resin. The content of the polyhydric alcohol is 110 to 1500 mass% with respect to the non-fibrous water-soluble polymer.

The present invention also provides an absorbent body comprising a base sheet and an absorbent core disposed on the base sheet, wherein the absorbent core comprises (a) a water-absorbent resin, (b) 1 or more selected from polyvinylpyrrolidone, polyvinyl butyral and dextrin, and (c) 1 or more selected from glycerol, propylene glycol and polyethylene glycol, and the absorbent body has a bending stiffness of 30g/20mm or less in at least one of the longitudinal direction and the transverse direction.

The present invention also provides an absorbent material comprising a base sheet and an absorbent core disposed on the base sheet, wherein the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer, a polyol, and porous particles, the content of the porous particles is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the water-absorbent resin, the loading rate of the water-absorbent resin in the absorbent material is 70% or more, and the absorption rate of 1 drop of the absorbent material is 30 seconds or less.

The present invention also provides an absorbent material comprising a base sheet and an absorbent core disposed on the base sheet, wherein the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer, a polyol, and porous particles, the water-absorbent resin is contained in the absorbent core in an amount of 40 to 95 mass%, the non-fibrous water-soluble polymer is contained in an amount of 0.1 to 5 mass% relative to the water-absorbent resin, the polyol is contained in an amount of 110 to 1500 mass% relative to the non-fibrous water-soluble polymer, and the porous particles are contained in an amount of 5 to 35 parts by mass relative to 100 parts by mass of the water-absorbent resin.

The present invention also provides an absorbent material comprising a base sheet and an absorbent core disposed on the base sheet, wherein the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer and a polyol, the water-absorbent resin is contained in the absorbent core in an amount of 40 to 95 mass%, the non-fibrous water-soluble polymer is contained in an amount of 0.1 to 5 mass% relative to the water-absorbent resin, the polyol is contained in an amount of 110 to 1500 mass% relative to the non-fibrous water-soluble polymer, and the water-absorbent resin has a median particle diameter of 150 to 500 μm.

Further, the present invention provides an absorbent article including the absorbent body.

Further, the present invention provides a method for producing an absorbent body, which is a suitable method for producing the absorbent body, comprising preparing a coating material in which a water-absorbent resin, a non-fibrous water-soluble polymer, and a polyol are dispersed or dissolved in a solvent, applying the coating material to one surface of a base sheet to form an application body, drying the application body, and fixing an absorbent core, which is a dried body of the application body, to the base sheet.

Drawings

Fig. 1 is a perspective view showing an apparatus that can be applied to the production of an absorbent body of the present invention.

Fig. 2 (a) and 2 (b) are perspective views each showing another apparatus which can be suitably used for producing the absorbent body of the present invention.

Detailed Description

The absorbent bodies described in patent documents 1 to 4 are essentially composed of a fiber component, and therefore may be deformed by warping during production or water absorption. When the absorbent body is warped, the wearer's body receives a local pressure when wearing the absorbent article, and therefore, a feeling of discomfort occurs and the wearing feeling is reduced.

In particular, in the technique described in patent document 4, an alkylene oxide polymer is required as a binder for the high-absorbency polymer and the fibers, and a large amount of the alkylene oxide polymer is required to develop the function thereof. In fact, in the examples of this document, an alkylene oxide-based polymer is added to the water-absorbent resin in an amount 5 times by mass. It is considered that the absorbent body is thus hardened, and when the absorbent body is used in an absorbent article such as a diaper, the absorbent article gives a feeling of discomfort when worn and the absorption performance is lowered. Further, since the absorbent body described in this document has a sponge-like structure, the absorbent body is considered to be bulky and thick. Further, it is considered that the absorbent body having a sponge-like structure described in this document has a large ratio of pores to the super absorbent polymer, and it is presumed that when the absorbent body absorbs water and is pressurized, the liquid returns to the surface, and the user may feel uncomfortable.

In the technique described in patent document 5, since the ratio of the powder contained as the filter aid is high, the absorbent body is hardened and the amount of the returned liquid increases.

The present invention provides an absorbent body, and more specifically, provides a thin absorbent body which is less likely to warp and has high flexibility, and a method for producing the same.

Further, the present invention provides an absorbent body which is thin, has high followability to the wearer's movement when not absorbing water, is hardly broken, has a high water absorption rate, and has high flexibility in which warping does not easily occur.

Further, the present invention provides an absorbent body which is thin, has a small amount of liquid returned, and has high flexibility.

The present invention will be described below based on preferred embodiments of the present invention. The absorbent body of the present invention includes a base sheet and an absorbent core on at least one side of the base sheet. The base sheet is used to improve the shape retention of the absorbent body by holding the absorbent core and to improve the handling properties of the absorbent body. Further, the substrate sheet can also be used as a coating substrate in the production of an absorbent core by the following method. On the other hand, the absorbent core is a main liquid absorption site in the absorbent body, and has a function of absorbing and holding liquid.

As the substrate sheet, a material capable of holding the absorbent core is used. The substrate sheet may be liquid-permeable, or may be liquid-impermeable or liquid-impermeable. The substrate sheet can be made of, for example, nonwoven fabric, paper, woven fabric, film, or the like. A laminate of 2 or more kinds of these materials may also be used as the substrate sheet. The substrate sheet preferably includes a liquid-permeable fibrous sheet from the viewpoint of diffusing a liquid in the planar direction.

As the nonwoven fabric, structures obtained by various production methods can be used without particular limitation. Examples of the nonwoven fabric include: spunlace nonwoven fabrics, spunbond nonwoven fabrics, hot air nonwoven fabrics, melt blown nonwoven fabrics, needle punched nonwoven fabrics, resin bonded nonwoven fabrics, and the like. These nonwoven fabrics may be used individually, or may be used in the form of a laminate of 2 or more types of nonwoven fabrics.

As the woven fabric, a structure having various fiber textures can be used. As the paper, a structure obtained by a wet paper making method or a dry paper making method using fibers capable of paper making as a raw material can be used. As the film, for example, a structure obtained by forming by a T-die method or an inflation method and uniaxially or biaxially stretching can be used.

As the various materials constituting the substrate sheet, for example, synthetic polymer materials such as various thermoplastic resins, or natural polymer materials such as cellulose such as pulp can be used. Examples of the thermoplastic resin include polyolefin fibers such as Polyethylene (PE) and polypropylene (PP), polyester fibers such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyacrylic fibers such as polyacrylic acid and polymethacrylate, and vinyl fibers such as polystyrene and polyvinyl chloride. These resins may be used alone or in admixture of 2 or more. When the fibers are formed of these resins, the fibers may be formed of a single resin, or may be formed of a core-sheath type or side-by-side type composite fiber.

From the viewpoint of shape retention of the absorbent body having the absorbent core retained thereon and handling of the absorbent body, the grammage of the base sheet is preferably 10g/m²Above, more preferably 15g/m²Above, more preferably 20g/m²The above. Further, from the viewpoint of thinness and flexibility of the absorbent body, the grammage of the base sheet is preferably 70g/m²Hereinafter, more preferably 65g/m²Hereinafter, more preferably 60g/m²The following. Specifically, the grammage of the substrate sheet is preferably 10g/m²Above and 70g/m²The amount of the surfactant is preferably 15g/m or less²Above and 65g/m²Hereinafter, more preferably 20g/m²Above and 60g/m²The following.

The absorbent core is located on at least one side of the substrate sheet. The absorbent core may be positioned on the base sheet in direct contact therewith, or may be indirectly adjacent to the base sheet with 1 or 2 or more members or layers interposed therebetween.

One of the features of the absorbent core is its thinness. Since the absorbent core is thin, the entire absorbent body has flexibility. From the viewpoint of sufficiently improving the flexibility of the absorbent body, the thickness of the absorbent core is preferably 5mm or less, more preferably 4.5mm or less, and still more preferably 4mm or less. In addition, from the viewpoint of exhibiting sufficient absorption performance despite being thin, the thickness thereof is preferably 0.3mm or more, more preferably 0.4mm or more, and still more preferably 0.5mm or more. Specifically, the thickness of the absorbent core is preferably 0.3mm or more and 5mm or less, more preferably 0.4mm or more and 4.5mm or less, and still more preferably 0.5mm or more and 4mm or less.

The absorbent core contains a water-absorbent resin, a non-fibrous water-soluble polymer, and a polyol as constituent materials thereof. By forming the absorbent core from these materials, the absorbent core can be made thin and the problem of warping that occurs in conventional thin absorbent cores can be eliminated. The details of each material will be described below.

The water-absorbent resin functions as a main water-absorbing material in the absorbent core. The water-absorbent resin includes a material that swells upon contact with water and is capable of absorbing and retaining water. The water-absorbent resin preferably can absorb and retain water in an amount of 20 times by mass or more of its own weight. In addition, the water-absorbent resin is preferably capable of absorbing and retaining 20 times or more, particularly 30 times or more of its own weight when the object is urine, and preferably capable of absorbing and retaining 1 time or more, preferably 3 times or more of its own weight when it is blood. The upper limit of the water absorption/retention of the water-absorbent resin is not particularly limited, and 1000 times the weight of the water-absorbent resin can be set as the upper limit. As the water-absorbent resin, various hydrogel materials, for example, crosslinked products of polymers or copolymers of acrylic acid or acrylic acid alkali metal salts, crosslinked products of polyacrylic acid and salts thereof and polyacrylate graft copolymers, crosslinked products of starch or carboxymethylated cellulose, crosslinked products of hydrolysis products of starch-acrylate graft copolymers, crosslinked products of vinyl alcohol-acrylate copolymers, crosslinked products of maleic anhydride-grafted polyvinyl alcohol, crosslinked isobutylene-maleic anhydride copolymers, saponified products of vinyl acetate-acrylate copolymers, and the like can be used. These water-absorbent resins may be used alone in 1 kind, or in combination of 2 or more kinds.

The water-absorbent resin is generally used as a particulate material, and may be in a fibrous form. When the particulate water-absorbent resin is used, the shape thereof may be any of spherical, block, bag or amorphous. When a particulate water-absorbent resin is used, the particle diameter is preferably a particle diameter D of cumulative volume 50% as measured by a laser diffraction particle size distribution method₅₀Is 15 μm or more, more preferably 20 μm or more, and still more preferably 25 μm or more. Further, the particle diameter D₅₀Preferably 400 μm or less, more preferably 350 μm or less, and still more preferably 300 μm or less. Specifically, the particle diameter D₅₀Preferably 15 to 400 μm, more preferably 20 to 350 μm, and still more preferably 25 to 300 μm.

From the viewpoint of sufficiently improving the absorption performance of the absorbent core, the content of the water-absorbent resin in the absorbent core is preferably 40% by mass or more, more preferably 45% by mass or more, and still more preferably 50% by mass or more. From the viewpoint of flexibility of the absorbent core, the content in the absorbent core is preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less. Specifically, the content of the water-absorbent resin in the absorbent core is preferably 40 mass% or more and 95 mass% or less, more preferably 45 mass% or more and 90 mass% or less, and still more preferably 50 mass% or more and 85 mass% or less.

The content ratio of the absorbent core included in the absorbent body, i.e., the ratio of the area of the absorbent core to the area of the absorbent body, is preferably 50 area% or more, more preferably 60 area% or more, and still more preferably 70 area% or more, from the viewpoint of sufficiently improving the absorption capacity of the absorbent body. In addition, from the viewpoint of liquid diffusibility in the absorbent core, the ratio of the area of the absorbent core to the area of the absorbent body is preferably 100 area% or less, more preferably 95 area% or less, and still more preferably 90 area% or less. Specifically, the ratio of the area of the absorbent core to the area of the absorbent body is preferably 50 area% or more and 100 area% or less, more preferably 60 area% or more and 95 area% or less, and still more preferably 70 area% or more and 90 area% or less. The "area of the absorbent core" and the "area of the absorbent core" are the areas of the surface of the base sheet on which the absorbent core is provided. The term "the ratio of the area of the absorbent core to the area of the absorbent body" is 100 area%, means that the absorbent core is disposed over the entire surface of the base sheet.

The ratio of the area of the absorbent core to the area of the absorbent body was measured by the method described below. The length of the substrate sheet in the longitudinal direction and the width direction was measured, and the area was calculated. Then, the length of the absorbent core in the longitudinal direction and the length in the width direction of the base sheet are measured to calculate the area. The ratio of the area of the absorbent core to the area of the substrate sheet was calculated to determine the ratio.

As a result of the investigation by the present inventors, it has been found that the particle diameter of the water-absorbent resin is preferably controlled in terms of reducing the amount of the back liquid. The reason for this is as follows. In the thin absorbent material such as the absorbent material of the present invention, it is necessary to increase the surface area of the water-absorbent resin, to increase the absorption rate, and to reduce the amount of liquid returned. For this purpose, it is conceivable to increase the surface area of the water-absorbent resin by pulverizing and/or classifying the water-absorbent resin to form fine particles.

In order to improve the absorption rate by controlling the particle diameter and particle size distribution of the water-absorbent resin and to reduce the amount of liquid returned, it is preferable to use a particulate water-absorbent resin, and in this case, the particle diameter is preferably a particle diameter D of 50% of the cumulative volume measured by a laser diffraction particle size distribution method₅₀Namely, the median particle diameter is 150 μm or more, preferably 160 μm or more, and more preferably 170 μm or more. The median particle diameter is preferably 500 μm or less, more preferably 450 μm or less, and still more preferably 400 μm or less. Specifically, the median particle diameter is preferably 150 μm or more and 500 μm or less, more preferably 160 μm or more and 450 μm or less, and still more preferably 170 μm or more and 400 μm or less.

When the water-absorbent resin is subjected to the crushing operation and/or the classification operation, the particles of the water-absorbent resin after the operation have a particle size distribution. In this case, the inventors have found, as a result of their studies, that when the distribution of the fine particles is large, in other words, when the range of development on the small particle diameter side in the particle size distribution curve is wide, the amount of liquid returning from the absorbent body increases. The reason is considered to be that: the small-particle-diameter water-absorbent resin reduces the gap in the absorbent body. From this viewpoint, in the particle size distribution of the water-absorbent resin, the particle diameter at 10% of the cumulative volume measured by the laser diffraction particle size distribution method is represented by D₁₀D represents a particle diameter at 90% of the cumulative volume₉₀When (D)₉₀-D₁₀)/D₅₀The value of (b) is preferably 0.10 or more, more preferably 0.20 or more, and still more preferably 0.30 or more. Furthermore, (D)₉₀-D₁₀)/D₅₀The value of (d) is preferably 1.60 or less, more preferably 1.50 or less, and still more preferably 1.40 or less. Specifically, (D)₉₀-D₁₀)/D₅₀The value of (d) is preferably 0.10 or more and 1.60 or less, more preferably 0.20 or more and 1.50 or less, and still more preferably 0.30 or more and 1.40 or less.

When the water-absorbent resin has the above-mentioned median particle diameter or particle size distribution, the content of the water-absorbent resin in the absorbent core is preferably 40% by mass or more, more preferably 45% by mass or more, and still more preferably 50% by mass or more, from the viewpoint of sufficiently improving the absorption performance of the absorbent core. From the viewpoint of flexibility of the absorbent core, the content in the absorbent core is preferably 95% by mass or less, more preferably 93% by mass or less, and still more preferably 91% by mass or less. Specifically, the content of the water-absorbent resin in the absorbent core is preferably 40 mass% or more and 95 mass% or less, more preferably 45 mass% or more and 93 mass% or less, and still more preferably 50 mass% or more and 91 mass% or less.

The non-fibrous water-soluble polymer contained in the absorbent core is mainly used for fixing the water-absorbent resin in the absorbent core. The term "non-fibrous water-soluble polymer" means, for example, a polymer such as cellulose microfibrils described in patent documents 1 to 3, which maintains a fibrous form even after liquid absorption, and is excluded from the scope of the present invention. Therefore, the non-fibrous water-soluble polymer in the present invention includes a water-soluble polymer which is fibrous before liquid absorption but is dissolved in water by liquid absorption to be in a non-fibrous shape. The term "water-soluble" means that the solubility of 100g of water at 25 ℃ is preferably 1g or more, more preferably 5g or more, and still more preferably 10g or more. As a measuring method, a predetermined amount of the object and 50mL of ion-exchanged water at 25 ℃ were added to and mixed with a 100mL glass beaker (5 mm. phi.), and a stirrer having a length of 20mm and a width of 7mm was placed therein, and stirred at 600rpm using a magnetic stirrer HPS-100 manufactured by AS ONE Ltd. As long as the total amount of the added object is dissolved in water within 24 hours, the object is judged to have "water solubility" 2 times its predetermined amount. In the present invention, as more preferable solubility, the total amount is preferably dissolved in water within 3 hours, and the total amount is more preferably dissolved in water within 30 minutes.

The present inventors have studied the cause of the occurrence of warpage in thin absorbers known in the prior art as in the above-mentioned patent documents 1 to 3, and have presumed that the occurrence of warpage is associated with microfibrous cellulose (hereinafter also referred to as "MFC") as a binder contained in the absorber. Specifically, the MFC fixes the MFCs to each other or the water-absorbent resin by a hydrogen bond. Therefore, when water retention or water evaporation occurs during the production of the absorbent body or during the absorption of liquid, the hydrogen-bonded fibers are easily deformed. As a result, the absorbent body is deformed and is considered to be warped. Further, since hydrogen bonding of MFC is not immediately broken immediately after the absorbent material absorbs water, it is considered that MFC deforms along with swelling of the water-absorbent resin, and the absorbent material itself warps.

In contrast, in the absorbent body of the present invention, a non-fibrous water-soluble polymer is contained in the absorbent core, and the polymer is used as a binder. Therefore, the absorbent body of the present invention can effectively suppress the occurrence of warpage even if water transfer occurs in the absorbent core at the time of its production or at the time of liquid absorption. The non-fibrous water-soluble polymer also has the following advantages: since the absorbent core dissolves by contact with water, the absorbent core is easily deformed by following an external force at the time of liquid absorption. From this viewpoint, in the absorbent body of the present invention, the absorbent core preferably does not contain a fibrous adhesive.

On the other hand, when a binder component is used for binding the water-absorbent resin to the fibers as in the above-mentioned patent document 4, a large amount of the binder component is required, and as a result, the surface of the water-absorbent resin is covered with the binder component, and it becomes difficult to exhibit the water absorption performance of the water-absorbent resin. In the technique of patent document 4, a porous sponge-like structure is obtained by the fibers, and the liquid can be held in the porous portion, but when the body pressure is applied, the body fluid cannot be held completely and leaks.

In the present invention, from the viewpoint of making the above-described various advantages brought about by the use of the non-fibrous water-soluble polymer more remarkable, the content of the non-fibrous water-soluble polymer in the absorbent core is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.5% by mass or more, relative to the water-absorbent resin. For the same reason, the content of the non-fibrous water-soluble polymer in the absorbent core is preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less, relative to the water-absorbent resin. Specifically, the content of the non-fibrous water-soluble polymer in the absorbent core is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.3% by mass or more and 4% by mass or less, and still more preferably 0.5% by mass or more and 3% by mass or less, relative to the water-absorbent resin. The "ratio of the non-fibrous water-soluble polymer to the water-absorbent resin" is a ratio calculated by using the mass of the water-absorbent resin contained in the absorbent core as a denominator and the non-fibrous water-soluble polymer as a molecule.

In addition, from the viewpoint of making the above-described various advantages brought about by the use of a non-fibrous water-soluble polymer more remarkable, examples of the water-soluble polymer include: polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl butyral, dextrin, polyethylene oxide, water-soluble nylon, etc., and among them, 1 or more selected from polyvinyl pyrrolidone, polyvinyl butyral, and dextrin is preferable. These non-fibrous water-soluble polymers may be used alone in 1 kind, or in combination with 2 or more kinds. Among these non-fibrous water-soluble polymers, polyvinylpyrrolidone is preferably used, and among them, polyvinylpyrrolidone of K-15, K-30, K-60 or K-90 grade is more preferable, particularly from the viewpoint of solubility in water and alcohols and binding force.

In connection with the use of a non-fibrous water-soluble polymer, in the absorbent body of the present invention, the absorbent core preferably does not contain a fibrous material. As the fiber material, there are natural fibers such as wood pulp and kenaf, synthetic fibers such as olefins and polyesters, regenerated fibers such as rayon, and the like. This further effectively prevents the absorbent body from being warped. The fiber material is a deformable material having a shape in which the length L is very long with respect to the thickness D. For example, a material having a shape with an L/D value of 3 or more is included in the category of the fiber material.

The polyhydric alcohol, which is a component contained in the absorbent core in addition to the water-absorbent resin and the non-fibrous water-soluble polymer, is mainly used for imparting flexibility to the absorbent core. The polyhydric alcohol preferably has higher wettability (hydration property) than the non-fibrous water-soluble polymer in terms of better liquid diffusibility in the absorbent core. The level of wettability (hydration) can be determined, for example, from the spread area of water after a certain period of time has elapsed since a certain amount of water was dropped onto a circular polyol spread in a certain area on a smooth glass plate. The larger the spread area of water, the higher the wettability (hydration), and the smaller the spread area of water, the lower the wettability (hydration). As a specific example of the determination method, for example, the polyol is spread as far as possible without unevenness to a 50mm square range on a smooth glass plate. Then, 1 drop (50. mu.g) of water was dropped to the center of the polyol face, and the area after 5 seconds was measured. The area may also be acquired in the form of an image and measured.

As the polyol, any of aliphatic polyols and aromatic polyols can be used. Among these, aliphatic polyols are preferably used from the viewpoint of further improving the flexibility of the absorbent core. As the aliphatic polyol, a saturated aliphatic polyol and an unsaturated aliphatic polyol can be used. From the viewpoint of further improving the flexibility of the absorbent core, saturated aliphatic polyols are particularly preferably used. As the saturated aliphatic polyol, for example, 1 or more selected from glycerol, propylene glycol and polyethylene glycol can be used, and 1 or 2 or more of these can be blended. Among them, glycerin is particularly preferably used.

From the viewpoint of imparting flexibility to the absorbent core, the content of the polyol in the absorbent core is preferably 110 mass% or more, more preferably 200 mass% or more, and still more preferably 300 mass% or more, relative to the non-fibrous water-soluble polymer. For the same reason, the content of the polyol in the absorbent core is preferably 1500% by mass or less, more preferably 1250% by mass or less, and still more preferably 1000% by mass or less, relative to the non-fibrous water-soluble polymer. Specifically, the content of the polyol in the absorbent core is preferably 110% by mass or more and 1500% by mass or less, more preferably 200% by mass or more and 1250% by mass or less, and still more preferably 300% by mass or more and 1000% by mass or less, relative to the non-fibrous water-soluble polymer.

In the present invention, as a specific example of a preferred embodiment, there is provided an absorbent body having a base sheet and an absorbent core on the base sheet, the absorbent core comprising (a) a water-absorbent resin, (b) 1 or more selected from polyvinylpyrrolidone, polyvinylbutyral and dextrin, and (c) 1 or more selected from glycerol, propylene glycol and polyethylene glycol, and having a bending stiffness of at least one of the longitudinal direction and the transverse direction of the absorbent body of 30g/20mm or less. As the absorbent body, it is particularly preferable that the bending stiffness in both the longitudinal direction and the transverse direction is 30g/20mm or less. Further, the absorber preferably has a warp of 4mm or less. The bending rigidity and warp can be measured by the methods described in the examples below.

In the absorbent body of the present invention, it is advantageous if the absorbent core contains porous particles in addition to the above components. The reason for this is as follows.

The invention realizes a thinner thickness by disposing a water-absorbent resin at a high density. However, it is known that a water-absorbent resin swells when it absorbs water. Therefore, spaces for swelling in response to water absorption are required between the particles of the water-absorbent resin, but when the water-absorbent resin is disposed at a high density, such spaces are hardly generated. As a result, swelling inhibition of the water-absorbent resin is likely to occur.

For the same reason, when the water-absorbent resin is disposed at a high density, water hardly penetrates from the surface to the inside of the absorbent core, and therefore, the diffusibility in the planar direction is low. In particular, if the water-absorbent resin located on the surface of the absorbent core swells, the space for water permeation is further reduced. As a result, the liquid permeation of water is easily hindered.

On the other hand, when the absorbent core contains porous particles, the space between the water-absorbent resins is created by the porous particles, although the density is high, and the swelling inhibition of the water-absorbent resins is less likely to occur. Further, the liquid permeation of water is less likely to be inhibited by the space, and the liquid diffusibility in the planar direction is improved. As a result, the absorption rate of the absorbent body increases, and the amount of liquid returning of the absorbed liquid decreases.

The space refers to both the space present between the particles of the water-absorbent resin and the space present in the porous particles.

From the viewpoint of making the above-mentioned advantages more remarkable, the particle diameter of the porous particles is preferably a particle diameter D of 50% of the cumulative volume as measured by a laser diffraction particle size distribution method₅₀Is 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more. Further, the particle diameter D₅₀Preferably 100 μm or less, more preferably 90 μm or less, and still more preferably 80 μm or less. Specifically, the particle diameter D₅₀Preferably 5 to 100 μm, more preferably 10 to 90 μm, and still more preferably 15 to 80 μm.

In order to form spaces between the particles of the water-absorbent resin, it is advantageous to adjust the ratio of the particle diameter of the water-absorbent resin particles to the particle diameter of the porous particles. From this viewpoint, the particle diameter D of the water-absorbent resin particles at a cumulative volume of 50% as measured by a laser diffraction particle size distribution method is₅₀D1 denotes the particle diameter D of the porous particles₅₀When D2 is used, the value D2/D1 is preferably 0.0125 or more, more preferably 0.025 or more, and still more preferably 0.05 or more. The value of D2/D1 is preferably 0.5 or less, more preferably 0.45 or less, and still more preferably 0.4 or less. Specifically, the value of D2/D1 is preferably 0.0125 or more and 0.5 or less, more preferably 0.025 or more and 0.45 or less, and still more preferably 0.05 or more and 0.4 or less. When 2 or more kinds of porous particles are used, D2 represents D of each porous particle₅₀Is calculated as the arithmetic mean of (1).

In view of forming spaces between the particles of the water-absorbent resin, it is also advantageous to adjust the degree of porosity of the porous particles.

As the porous particles, inorganic materials are preferably used. For example, zeolite, perlite, diatomaceous earth, activated carbon, vermiculite, etc. can be used. In terms of increasing the absorption rate and reducing the amount of the back liquid, it is particularly preferable to use at least 1 selected from the group consisting of zeolite, perlite and diatomaceous earth. Even when 2 or more kinds of porous particles are used, the absorption rate can be further improved and the amount of returned liquid can be further remarkably reduced. For example, zeolite is a material advantageous in terms of reducing the amount of return liquid, and diatomaceous earth is a material advantageous in terms of increasing the absorption rate, and therefore, by combining these two materials, it is possible to further increase the absorption rate and further reduce the amount of return liquid.

As a result of the study by the present inventors, it was found that the porous particles exhibit a significant effect with a relatively small amount of use. Specifically, the content of the porous particles in the absorbent core is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 25 parts by mass or less, per 100 parts by mass of the water-absorbent resin. The content of the porous particles is preferably 5 parts by mass or more, more preferably 7.5 parts by mass or more, and still more preferably 10 parts by mass or more, per 100 parts by mass of the water-absorbent resin. Specifically, the content of the porous particles is preferably 5 parts by mass or more and 35 parts by mass, more preferably 7.5 parts by mass or more and 30 parts by mass, and still more preferably 10 parts by mass or more and 25 parts by mass, based on 100 parts by mass of the water-absorbent resin.

The absorbent core of the present invention containing the porous particles has an improved absorption rate. As one of the criteria of the absorption rate of the absorbent body, the 1-drop absorption rate is known, and the absorption rate of the absorbent body of the present invention for 1 drop is preferably 30 seconds or less, more preferably 25 seconds or less, and further preferably 20 seconds or less.

When the absorbent core of the present invention contains porous particles, the water-absorbent resin is less likely to fall off from the absorbent core. The reason for this is that: the absorbent core contains a non-fibrous water-soluble polymer. The water-absorbent resin is prevented from falling off from the absorbent core by the bonding force of the water-soluble polymer. The degree of difficulty in the water-absorbent resin falling off from the absorbent core can be expressed as a load factor. The loading ratio is a value obtained by subtracting the falling rate of the water-absorbent resin from 100. Namely, the loading rate (%) was 100 — shedding rate (%). The method for measuring the exfoliation rate is described in detail in the examples. In the absorbent body of the present invention, the loading ratio of the water-absorbent resin is preferably a high value of 70% or more, more preferably 75% or more, and still more preferably 80% or more. The method of measuring the carrying rate is described in detail in examples.

When the absorbent core of the present invention contains porous particles, the particle diameter of the water-absorbent resin contained in the absorbent core is preferably a particle diameter D of 50% of the cumulative volume measured by a laser diffraction particle size distribution method₅₀Is 150 μm or more, more preferably 160 μm or more, and still more preferably 170 μm or more. Further, the particle diameter D₅₀Preferably 500 μm or less, more preferably 450 μm or less, and still more preferably 400 μm or less. Specifically, the particle diameter D₅₀Preferably 150 to 500 μm, more preferably 160 to 450 μm, and still more preferably 170 to 400 μm.

When the absorbent core of the present invention contains porous particles, the absorbent core is further reduced in thickness and therefore is more flexible. The flexibility of the absorbent body can be evaluated as a value of bending stiffness. The absorbent body of the present invention has a flexible structure having a bending stiffness of at least one of the longitudinal direction and the transverse direction of preferably 30g/20mm or less, more preferably 25g/20mm or less, and still more preferably 20g/20mm or less. It is particularly preferable that the bending stiffness in both the longitudinal direction and the transverse direction is equal to or lower than the above value. The bending stiffness can be measured by the method described in the following examples. The longitudinal direction in the absorbent body can be, for example, a machine direction in the case of manufacturing the absorbent body by the following method, but is not limited thereto, and can be any direction in the plane of the absorbent body. The transverse direction is a direction orthogonal to the longitudinal direction.

In addition to the above components, the absorbent core may contain components capable of improving various performances of the absorbent core as required. Examples of such components include a thickener and a pH adjuster.

In the absorbent body of the present invention, the absorbent core may be continuously formed without a gap on at least one surface of the base sheet, or may be formed so that a part of the surface of the base sheet is exposed. For example, when the base sheet is rectangular, the absorbent core can be formed only in the region between the left and right side regions. Alternatively, a plurality of absorbent cores may be formed to extend in stripes in one direction, and the surface of the base sheet may be exposed in the region between the adjacent absorbent cores. Further, the absorbent core may be arranged in a checkered pattern.

When the shape of the absorbent core in plan view is any of the above, the thickness of the absorbent core is preferably the above value.

The thickness of the absorbent core was measured by the following method. That is, the absorbent core of the measurement target site was placed in a horizontal position without wrinkles or folds and measured at 5cN/cm²Thickness under load. Specifically, for the measurement of the thickness, for example, a thickness meter (PEACOCK (registered trademark) DIAL UPRIGHT GAUGES R5-C, manufactured by Nagasaki corporation) is used. At this time, the load is set to 5cN/cm between the front end of the thickness gauge and the cut object to be measured²The thickness was measured by arranging a plate (acrylic plate having a thickness of about 5 mm) which was adjusted to have a circular or square shape in plan view. The thickness of the absorbent body and the thickness of the base sheet were measured, and the difference was set as the thickness of the absorbent core.

The above description has been made on the structure in which the absorbent core is substantially single-layered, but in the present invention, the absorbent core may include a laminate structural section of 2 or more layers having the same composition or having different compositions. In this case, the shape of the absorbent core and the thickness of the absorbent core (the thickness of the maximum thickness portion) in a plan view are also preferably as described above.

The absorbent body of the present invention can be preferably obtained by applying the coating material for producing the absorbent core to at least one surface of the base sheet. Fig. 1 shows a device 10 that is preferable for producing an absorbent body by such a method. The apparatus 10 for producing an absorbent body shown in the figure includes: a supply section 20 for the paint, an application section 30 for the paint, and a drying section 40 for the paint. Hereinafter, each part will be explained.

The supply section 20 includes a reservoir 21 of paint. Paint 11 is stored in tank 21. The paint 11 in the tank 21 is stirred by the stirring blade 22 to be homogenized. The stirring blade 22 is connected to a rotation drive source 24 such as a motor via a shaft 23. One end of the pipe 25 is connected to the bottom of the tank 21. The other end of the pipe 25 is connected to the coating section 30.

The coating section 30 includes a coating head 31. The coating head 31 coats the coating material supplied from the reservoir tank 21 via the pipe line 25 on one surface of the long base material sheet 12 continuously conveyed in one direction D. As the application head 31, a member capable of applying a fluid is used. Examples of such an application head 31 include a die coater, but are not limited thereto. In fig. 1 is shown: the coating head 31 applies the coating material to the area between the both

side areas

12a, 12a of the base material sheet 12 to form the coating body 13 in a wet state.

The drying section 40 is disposed downstream of the coating section 30 as viewed in the conveyance direction D of the substrate sheet 12. The drying section 40 includes a drying device 41. The drying device 41 dries the coating body 13 formed by the coating section 30 to remove volatile matter, thereby fixing the absorbent core 14, which is a dried body of the coating body 13, to the base sheet 12. As the drying device 41, a mechanism capable of removing volatile matter from the wet coating body 13 is used. Examples of such a drying device 41 include: an infrared radiation device, a heated hot air blowing device, and the like, but the present invention is not limited thereto.

An absorbent body 16 having an absorbent core 14 formed on one surface of the base sheet 12 is thus obtained. The absorber 16 is post-treated as necessary. Examples of the post-treatment include: a step of cutting the long absorbent body 16 in the width direction thereof to process the absorbent body into a single body; a step of incorporating the absorbent body 16 into a final product such as an absorbent article; a step of winding the absorber 16 to form a blank.

According to the above method, there is an advantage that the intended absorbent core and absorbent body can be obtained by a simple process of applying only the coating material to the base sheet. Besides, the device has the advantage of light load on the device and operation. Further, since the number of steps is small, there is an advantage that investment in equipment can be reduced. In addition, in the absorbent body manufactured by the above method, the absorbent core is more densified than in the prior art, and therefore, it is easy to maintain high absorption performance and to make the absorbent body and the product including the absorbent body thin, and the absorbent body and the product including the absorbent body can be made compact. In addition, in the absorbent body manufactured by the above method, the thickness or grammage of the absorbent core is highly controlled, and local unevenness is less likely to occur in the grammage or thickness. Therefore, the absorbent body exhibits stable absorption performance. Further, in the absorbent body manufactured by the above method, the absorbent core can be formed extremely thin. Further, the grammage of the absorbent core can be arbitrarily changed over a wide area of the base sheet. Further, the surface of the absorbent core can be made flat. As a result of these techniques, the absorbent body produced by the above method can be made extremely high in flexibility. Further, the water-absorbent resin can be reliably fixed in the absorbent core regardless of the grammage of the water-absorbent resin.

With respect to the flatness of the surface of the absorbent core, measurement was made based on a surface image of the absorbent core taken with a microscope (VHX-5000, manufactured by KEYENCE). The maximum height roughness Rz of the surface indicating the maximum difference in concavity and convexity measured from the image of the absorbent core is preferably 1.5mm or less, more preferably 1.25mm or less, and still more preferably 1.0mm or less. By making the surface of the absorbent core flat, for example, when an absorbent article having the absorbent core is worn, a good wearing feeling can be obtained. The maximum height roughness Rz of the surface is based on JIS B0601: 2013. The smaller the maximum height roughness Rz is, the more preferable it is, the closer to 0, and a specific lower limit value is 0.01 mm.

From the viewpoint of further improving the above effects, the coating material to be used is preferably one obtained by dispersing or dissolving the water-absorbent resin, the non-fibrous water-soluble polymer, and the polyol in a solvent. The coating material may further contain porous particles. The coating material may contain water to such an extent that the water-absorbent resin does not swell, but the coating material preferably contains no water in order that the water-absorbent resin does not absorb water or swell in the coating material. The term "water-free" means that water is excluded from the coating material in an amount of interest. Therefore, a trace amount of water inevitably mixed in as impurities of the raw material or a trace amount of water inevitably mixed from the atmosphere is allowed to exist. The lower the water content in the coating, the better.

The ratio of the water-absorbent resin, the non-fibrous water-soluble polymer, and the polyol contained in the coating material can be set to be the same as the ratio of the water-absorbent resin, the non-fibrous water-soluble polymer, and the polyol contained in the absorbent core. When the coating material contains porous particles, the ratio of the porous particles can be set to be the same as the ratio of the porous particles contained in the absorbent core. Furthermore, the coating preferably does not contain fibrous material.

As the solvent contained in the coating material, a nonaqueous solvent can be preferably used. Examples of such a nonaqueous solvent include: ethanol, methanol, isopropanol, acetone, methyl ethyl ketone, butyl acetate, and the like. These nonaqueous solvents can be used alone in 1 kind, or in combination of 2 or more kinds. Among these nonaqueous solvents, ethanol is preferably used in terms of ease of acquisition, versatility and safety.

The ratio of the nonaqueous solvent to the coating material is preferably 30% by mass or more, more preferably 35% by mass or more, and still more preferably 40% by mass or more, from the viewpoint of smoothly and efficiently coating the coating material. From the same viewpoint, the ratio of the nonaqueous solvent to the coating material is preferably 70% by mass or less, more preferably 65% by mass or less, and still more preferably 60% by mass or less. Specifically, the ratio of the nonaqueous solvent to the coating material is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less.

Fig. 2 (a) and 2 (b) show another device different from the device 10 shown in fig. 1. In the apparatus 10A shown in fig. 2 (a), the structure of the application head 31A of the application section 30A is different from the structure of the application head 31 shown in fig. 1. The coating head 31A shown in fig. 2 (a) has a structure in which the coating bodies 13A can be formed at intervals along the conveying direction D of the substrate sheet 12 and along the width direction W orthogonal to the conveying direction. As a result, according to the present apparatus 10A, a plurality of coating body rows 15A are formed at intervals along the width direction W, and the coating body rows 15A include a plurality of coating bodies 13A formed at intervals along the conveyance direction D.

In the apparatus 10B shown in fig. 2 (B), the coating section 30B includes 2 coating heads 31B and 31C. The coating heads 31B and 31C are arranged in series along the conveyance direction D of the substrate sheet 12. The coating head 31B is disposed on the upstream side and the coating head 31C is disposed on the downstream side as viewed in the conveyance direction D. The coating head 31B applies a coating material to a region between the both

side regions

12a, 12a of the base material sheet 12 to form a first coated body 13B. On the other hand, the coating head 31C forms the second coating body 13C having a width narrower than that of the first coating body 13B on the first coating body 13B. The second coated body 13C is formed on the center in the width direction of the first coated body 13B. The composition of the paint for forming the first coated body 13B and the composition of the paint for forming the second coated body 13C may be different from each other or may be the same. As a result, according to the present apparatus 10B, when the absorbent body is viewed in the width direction W, the central region has a plurality of absorbent core structures such as a 2-layer structure, and the side regions located on both sides thereof have a single-layer structure. As a result, the absorbent body has different thicknesses in the central region and the side regions, and different absorption performance. In the apparatus 10B shown in fig. 2 (B), 2 coating heads are arranged in series, but 2 layers may be discharged from one coating head. Alternatively, the second layer may not be formed in the central portion. Alternatively, the second layer may be a plurality of layers. Further, 3 or more layers may be overlapped instead of 2 layers.

The absorbent body of the present invention obtained by each of the above methods can be preferably used as an absorbent body for various absorbent articles such as disposable diapers and sanitary napkins. In this case, by using the absorbent body of the present invention as the absorbent body, the absorbent article can have good fit to the body and can provide comfortable wearing feeling both in the case where the absorbent body is dry and in the case where the absorbent body is wet.

The present invention further discloses the following absorbent material and a method for producing the same in relation to the above embodiment.

＜1＞

An absorbent core disposed on a base sheet, wherein the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer, and a polyol, the water-absorbent resin content is 40 mass% or more and 95 mass% or less with respect to the absorbent core, the non-fibrous water-soluble polymer content is 0.1 mass% or more and 5 mass% or less with respect to the water-absorbent resin, and the polyol content is 110 mass% or more and 1500 mass% or less with respect to the non-fibrous water-soluble polymer.

＜2＞

The absorbent body according to < 1 >, wherein the maximum height roughness Rz of the surface of the absorbent core is 1.5mm or less, preferably 1.25mm or less, and more preferably 1.0mm or less.

＜3＞

The absorbent material according to < 1 > or < 2 >, wherein the non-fibrous water-soluble polymer is at least 1 selected from the group consisting of polyvinylpyrrolidone, polyvinylbutyral and dextrin, and is preferably polyvinylpyrrolidone.

＜4＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 3 >, wherein the polyhydric alcohol is at least 1 selected from the group consisting of glycerol, propylene glycol and polyethylene glycol, and glycerol is more preferred.

＜5＞

The absorbent body according to any one of the above-mentioned < 1 > to < 4 >, wherein a ratio of an area of the absorbent core to an area of the absorbent body is 50% or more and 100% or less, preferably 60% or more and 95% or less, and more preferably 70% or more and 90% or less.

＜6＞

The absorbent body according to any one of said < 1 > to < 5 >, wherein said absorbent core does not contain a fibrous material.

＜7＞

The absorbent body according to any one of the above-mentioned < 1 > to < 6 >, wherein the thickness of the absorbent core is preferably 0.3mm or more and 5mm or less, more preferably 0.4mm or more and 4.5mm or less, and still more preferably 0.5mm or more and 4mm or less.

＜8＞

The absorbent body according to any one of the above-mentioned < 1 > to < 7 >, wherein a content of the water-absorbent resin in the absorbent core is 40% by mass or more and 95% by mass or less, preferably 45% by mass or more and 90% by mass or less, and more preferably 50% by mass or more and 85% by mass or less.

＜9＞

The absorbent material according to any one of the above-mentioned items < 1 > to < 8 >, wherein a content of the non-fibrous water-soluble polymer is preferably 0.3% by mass or more and 4% by mass or less, and more preferably 0.5% by mass or more and 3% by mass or less, relative to the water-absorbent resin.

＜10＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 9 >, wherein the content of the polyol in the absorbent core is preferably 200 mass% or more and 1250 mass% or less, and more preferably 300 mass% or more and 1000 mass% or less, with respect to the non-fibrous water-soluble polymer.

＜11＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 10 >, wherein the absorbent core includes 2 or more layers of laminated structure sections having the same composition or different compositions.

＜12＞

The absorbent body according to < 11 > wherein the absorbent body has a multi-layered absorbent core structure in a central region and a single-layered structure in side regions on both sides when viewed in the width direction of the absorbent body.

＜13＞

As described in any of said < 1 > to < 12 >Wherein the grammage of the substrate sheet is preferably 10g/m²Above and 70g/m²The amount of the surfactant is preferably 15g/m or less²Above and 65g/m²Hereinafter, more preferably 20g/m²Above and 60g/m²The following.

＜14＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 13 >, wherein the substrate sheet is a liquid-permeable fibrous sheet.

＜15＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 14 >, wherein the base sheet is composed of 1 or more selected from the group consisting of nonwoven fabric, paper, woven fabric and film.

＜16＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 15 >, wherein the absorbent core is disposed on the entire surface of the base sheet.

＜17＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 15 >, wherein the base sheet has a rectangular shape, and the absorbent core is formed only in a region between both left and right side regions of the base sheet.

＜18＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 15 >, wherein the plurality of absorbent cores are formed on the base sheet so as to extend in stripes in one direction, and a surface of the base sheet is exposed in a region between adjacent absorbent cores.

＜19＞

The absorbent body according to any one of the above-mentioned items < 1 > to < 15 >, wherein the absorbent core is disposed in a checkered pattern on the base sheet.

＜20＞

An absorbent article comprising the absorbent body as described in any one of the above-mentioned < 1 > to < 19 >.

＜21＞

The absorbent article according to < 20 > wherein the absorbent body is provided between the liquid-permeable front sheet and the back sheet.

＜22＞

The absorbent article according to < 20 > or < 21 >, wherein the absorbent article is a disposable diaper or a sanitary napkin.

＜23＞

A method for producing an absorbent body, which comprises preparing a coating material in which a water-absorbent resin, a non-fibrous water-soluble polymer and a polyhydric alcohol are dispersed or dissolved in a solvent, applying the coating material to one surface of a base sheet to form an application body, drying the application body to remove volatile components, and fixing an absorbent core, which is a dried body of the application body, to the base sheet.

＜24＞

The method for producing an absorbent body according to the above < 23 >, comprising the steps of: the base sheet is a long strip continuously fed, and the long strip-shaped absorber is cut in the width direction thereof and processed into a single absorber.

＜25＞

The method for producing an absorbent body according to the above < 23 > or < 24 >, comprising the steps of: the absorbent body is incorporated into an absorbent article or the like final product.

＜26＞

The method for producing an absorbent body according to any one of the above-mentioned items < 23 > to < 25 >, comprising the steps of: the long absorbent body is wound to form a blank.

＜27＞

The method for producing an absorbent body according to any one of the above-mentioned items < 23 > to < 26 >, wherein the solvent is a nonaqueous solvent containing no water.

＜28＞

The method for producing an absorbent body according to any one of the above-mentioned items < 23 > to < 27 >, wherein the nonaqueous solvent is 1 or 2 or more selected from ethanol, methanol, isopropyl alcohol, acetone, methyl ethyl ketone and butyl acetate, and preferably ethanol.

＜29＞

The method for producing an absorbent body according to any one of the above-mentioned items < 23 > to < 28 >, wherein a ratio of the nonaqueous solvent to the coating material is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less.

＜30＞

The method for producing an absorbent body according to any one of the above-mentioned items < 23 > to < 29 >, wherein the coating material does not contain a fibrous material.

＜31＞

The method of manufacturing an absorbent body according to any one of the above < 23 > to < 30 >, wherein the coated bodies are formed at intervals along a transport direction of the base sheet and along a width direction orthogonal to the transport direction.

＜32＞

The method of manufacturing an absorbent body according to any one of the items < 23 > to < 30 >, wherein the first coating body is formed by applying the coating material to a region between the regions of the two side portions of the base sheet on an upstream side and the second coating body is formed on the first coating body on a downstream side, the second coating body having a width smaller than that of the first coating body, as viewed in the transport direction.

＜33＞

The method of producing an absorbent body according to the above < 32 >, wherein the coating is performed so that a central region has a 2-layer structure and side regions located on both sides have a single-layer structure when the absorbent body is viewed in a width direction thereof.

＜34＞

An absorbent core disposed on a base sheet, wherein the absorbent core comprises (a) a water-absorbent resin, (b) at least one member selected from the group consisting of polyvinylpyrrolidone, polyvinylbutyral and dextrin, and (c) at least one member selected from the group consisting of glycerol, propylene glycol and polyethylene glycol, and the absorbent core has a bending stiffness of 30g/20mm or less in at least one of the longitudinal direction and the transverse direction.

＜35＞

An absorbent article comprising the absorbent body as described in < 34 >.

＜36＞

The absorbent article according to < 35 > wherein the absorbent body is disposed between a liquid-permeable front sheet provided on the absorbent core side and a back sheet provided on the base sheet side.

＜37＞

An absorbent material comprising a base sheet and an absorbent core disposed on the base sheet, wherein the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer, a polyol and porous particles,

the content of the porous particles is 5 to 35 parts by mass based on 100 parts by mass of the water-absorbent resin,

the absorbent material has a loading ratio of the water-absorbent resin of 70% or more,

the absorption rate of 1 drop of the absorbent body is 30 seconds or less.

＜38＞

An absorbent body having a base sheet and an absorbent core provided on the base sheet, wherein in the absorbent body,

the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer, a polyol, and porous particles,

the content of the water-absorbent resin in the absorbent core is 40 to 95 mass%,

the content of the non-fibrous water-soluble polymer is 0.1 to 5 mass% based on the water-absorbent resin,

the content of the polyhydric alcohol is 110 to 1500 mass% relative to the non-fibrous water-soluble polymer,

the content of the porous particles is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the water-absorbent resin.

＜39＞

The absorbent body according to the above < 37 > or < 38 >, wherein the bending stiffness of the absorbent body in at least one of the longitudinal direction and the transverse direction is 30g/20mm or less.

＜40＞

The absorbent body according to any one of the above-mentioned < 37 > to < 39 >, wherein the thickness of the absorbent core is preferably 0.3mm or more and 5mm or less, more preferably 0.4mm or more and 4.5mm or less, and still more preferably 0.5mm or more and 4mm or less.

＜41＞

The absorber according to any one of the above-mentioned < 37 > to < 40 >, wherein the porous particles are at least 1 selected from the group consisting of zeolite, perlite, activated carbon, vermiculite and diatomaceous earth.

＜42＞

The absorbent body according to any one of the above-mentioned items < 37 > to < 41 >, wherein a ratio of an area of the absorbent core to an area of the absorbent body is preferably 50% by area or more and 100% by area or less, more preferably 60% by area or more and 95% by area or less, and still more preferably 70% by area or more and 90% by area or less.

＜43＞

The absorbent body according to any one of said items < 37 > to < 42 >, wherein said absorbent core does not contain a fibrous material.

＜44＞

The absorbent material according to any one of < 37 > to < 43 >, wherein the water-absorbent resin preferably has a particle diameter D of 50% of the cumulative volume as measured by a laser diffraction particle size distribution method₅₀Is 150 to 500 μm, more preferably 160 to 450 μm, and still more preferably 170 to 400 μm.

＜45＞

The absorbent according to any one of < 37 > to < 44 >, wherein the porous particles preferably have a particle diameter D of 50% of a cumulative volume as measured by a laser diffraction particle size distribution method₅₀Is 5 to 100 μm, more preferably 10 to 90 μm, and still more preferably 15 to 80 μm.

＜46＞

The absorber according to any one of < 37 > to < 45 >, wherein the absorber is to be diffracted by laser lightThe particle diameter D of the water-absorbent resin particles at a cumulative volume of 50% as measured by the particle size distribution method₅₀D1 represents the particle diameter D of the porous particles₅₀When D2 is used, the value of D2/D1 is preferably 0.0125 or more and 0.5 or less, more preferably 0.025 or more and 0.45 or less, and still more preferably 0.05 or more and 0.4 or less.

＜47＞

The absorbent material according to any one of < 37 > to < 46 >, wherein the porous particles are preferably contained in an amount of 7.5 parts by mass or more and 30 parts by mass, and more preferably 10 parts by mass or more and 25 parts by mass, based on 100 parts by mass of the water-absorbent resin.

＜48＞

The absorbent material according to any one of the above-mentioned items < 37 > to < 47 >, wherein the loading ratio of the water-absorbent resin is preferably 75% or more, and more preferably 80% or more.

＜49＞

The absorbent material according to any one of the above-mentioned items < 37 > to < 48 >, wherein the absorption rate of 1 drop of the absorbent material is preferably 25 seconds or less, and more preferably 20 seconds or less.

＜50＞

The absorbent body according to any one of the above-mentioned items < 37 > to < 49 >, wherein the bending stiffness of the absorbent body in at least one of the longitudinal direction and the transverse direction is preferably 30g/20mm or less, more preferably 25g/20mm or less, and still more preferably 20g/20mm or less.

＜51＞

the absorbent core comprises a water-absorbent resin, a non-fibrous water-soluble polymer and a polyhydric alcohol,

the median particle diameter of the water-absorbent resin is 150 to 500 [ mu ] m.

＜52＞

The absorbent body according to the above < 51 >, wherein the thickness of the absorbent core is preferably 0.3mm or more and 5mm or less, more preferably 0.4mm or more and 4.5mm or less, and still more preferably 0.5mm or more and 4mm or less.

＜53＞

The absorbent body according to the above < 51 > or < 52 >, wherein the ratio of the area of the absorbent core to the area of the absorbent body is 50% or more and 100% or less, preferably 60% or more and 95% or less, and more preferably 70% or more and 90% or less.

＜54＞

The absorbent body according to any one of said items < 51 > to < 53 >, wherein said absorbent core does not contain a fibrous material.

＜55＞

The absorbent material according to any one of the items < 51 > to < 54 >, wherein the water-absorbent resin has a particle size distribution in which D represents a particle size of 10% of a cumulative volume measured by a laser diffraction particle size distribution method₁₀D represents a particle diameter at 50% of the cumulative volume₅₀D represents a particle diameter at 90% of the cumulative volume₉₀When (D)₉₀-D₁₀)/D₅₀The value of (b) is 0.10 or more and 1.60 or less.

＜56＞

The absorbent material according to < 55 > above, wherein the water-absorbent resin has the formula (D)₉₀-D₁₀)/D₅₀The value of (d) is more preferably 0.20 to 1.50, and still more preferably 0.30 to 1.40.

＜57＞

The absorbent material according to any one of the above-mentioned items < 51 > to < 56 >, wherein the median particle diameter of the water-absorbent resin is more preferably 160 μm or more and 450 μm or less, and still more preferably 170 μm or more and 400 μm or less.

[ examples ]

The present invention will be described in further detail below with reference to examples. However, the scope of the present invention is not limited by this example. Unless otherwise specified, "%" means "% by mass".

[ example 1-1]

Coating liquids having the compositions shown in table 1 below were prepared. A metal plate having a thickness of 0.3mm and having a grid opening of 50mm square was placed on an 80X 120mm substrate sheet, and the prepared coating liquid was dropped and applied to the size of the grid. The sheet coated with the coating liquid was dried in an electric drying oven set to 80 ℃ for about 5 minutes, and thereafter left to stand in a normal temperature environment for about 10 minutes. The absorbent body obtained in this manner was cut into a size of an absorbent core of 50mm square to prepare a sample for evaluation. As the substrate sheet, a spunlace nonwoven fabric (a grammage of 35 g/m) containing PET, PE, rayon fiber was used²). As the water-absorbent resin, a polyacrylic acid sodium salt polymer (manufactured by SUNDIA, Inc., IM997) was pulverized to have a particle diameter D₅₀Is 160 μm material. In tables 1 and 2, the unit of "addition amount" is represented by g, and the compounding ratio is represented by "% by mass".

[ Table 1]

[ examples 1-2]

An absorbent body was produced in the same manner as in example 1-1, except that propylene glycol (manufactured by ADEKA corporation, propylene glycol for cosmetics) was used in place of glycerin in example 1-1.

[ examples 1 to 3]

An absorbent body was produced in the same manner as in example 1-1, except that polyethylene glycol (PEG-400, manufactured by Sanyo chemical industries, Ltd.) was used instead of glycerin in example 1-1.

[ examples 1 to 4]

An absorbent body was produced in the same manner as in example 1-1, except that polyvinyl butyral (S-LECB K BM-1, manufactured by hydroprocessor chemical industries, Ltd.) was used instead of polyvinylpyrrolidone as the non-fibrous water-soluble polymer in example 1-1.

[ examples 1 to 5]

An absorbent was produced in the same manner as in example 1-1, except that dextrin (sun deck #185N, manufactured by Sanko starch industries, Ltd.) was used instead of polyvinylpyrrolidone as the non-fibrous water-soluble polymer in example 1-1.

Examples 1 to 6 and 1 to 7

An absorbent body was produced in the same manner as in example 1-1, except that the composition of the coating liquid was changed as shown in table 1.

Comparative examples 1-1 to 1-4

Coating liquids having the compositions shown in table 2 below were prepared. Except for this, an absorbent body was obtained in the same manner as in example 1-1. In comparative example 1-1, microfibril cellulose (manufactured by Daicel corporation, Celish) was used as a binder.

[ Table 2]

[ evaluation ]

The thickness and the maximum height roughness of the surface of the absorbent core and the ratio of the mass of the water-absorbent resin in the absorbent core were measured by the above-described methods for the absorbent bodies obtained in examples and comparative examples. Further, the bending rigidity, warp degree and 1-drop absorption speed of the absorbent body were measured by the following methods. The results are shown in table 3 below.

[ bending rigidity of absorbent body ]

The bending stiffness of the absorber can be evaluated from the three-point bending load. The smaller the value of the bending load, the higher the flexibility, i.e., the lower the bending rigidity can be judged. The measurement of the three-point bending load was performed in the following manner. The measurer uses a Handle-O-Meter. The measurement sample of the absorber was a square of 50mm square. The measurement sample is mounted between a pair of plate-like supports. The spacing of the supports was 20 mm. A plate-like press-fitting body is press-fitted to a measurement sample from above the measurement sample stretched between support bodies. The plate-like indentation had a width of 2mm and a length longer than that of the test specimen. The plate-like press-fitting body is pressed into the support body at a position intermediate between the pair of support bodies. The plate-like press-fitting body was press-fitted into the support body by 15mm, and the maximum value of the load generated between the movement amounts was set to a three-point bending load. The bending stiffness was evaluated by measuring three-point bending loads in the Machine Direction (MD) and the direction (CD) orthogonal to the machine direction.

[ warping degree ]

A50 mm square measurement specimen is placed on a flat, smooth floor or board and the maximum height of the measurement specimen from the floor or board is measured. In addition, the measured temperature is 25 ℃ and the humidity is 20-60% RH. The measurement was performed within 5 minutes after the preparation.

[1 drop absorption Rate ]

1 drop of physiological saline was dropped on the surface of the absorbent core of the measurement sample of 50mm square. The time from the moment when the liquid contacted the measurement sample until the measurement sample absorbed water was measured, and its value was set as the absorption rate of 1 drop.

[ Table 3]

As is clear from the results shown in table 3, the absorbent bodies of the examples have lower values of bending stiffness and are less likely to cause warpage than the absorbent body of the comparative example.

[ examples 2-1 to 2-4]

Using the following raw materials, coating liquids having the compositions shown in table 4 below were prepared. A metal plate having a thickness of 0.3mm and having a grid opening of 50mm square was placed on an 80X 120mm substrate sheet, and the prepared coating liquid was applied to the size of the grid. The sheet coated with the coating liquid was dried in an electric drying oven set to 80 ℃ for about 5 minutes, and thereafter left to stand in a normal temperature environment for about 10 minutes. The absorbent obtained in this manner was cut into a size of an absorbent core of 50mm square to prepare an absorbent core for evaluationThe sample of (1). As the base sheet, a spunlace nonwoven fabric (a grammage of 35 g/m) containing PET, PE and rayon fibers was used²). As the water-absorbent resin, a polyacrylic acid sodium salt polymer (IM 997, manufactured by San-Dia Polymers Co., Ltd.) was pulverized and used so as to have a particle diameter D₅₀Is 160 μm material.

< raw materials >

Ethanol: manufactured by Japan Synthetic Alcohol corporation, Synthetic Alcohol 95 degree polyvinylpyrrolidone: luviskol (registered trademark) K90, manufactured by BASF corporation

Glycerol: cosmetic concentrated glycerin manufactured by Huawang corporation

Zeolite: SGW-B4 manufactured by Zeeklite corporation

Diatomite: manufactured by Showa chemical industries, Ltd, Radiolite #2000S

Perlite: topco (registered trademark) 38 manufactured by Showa chemical industries, Ltd

Hydroxypropyl cellulose: HPC-H manufactured by Nippon Caoda Ltd

Comparative example 2-1

Patent document 2 was further verified in this comparative example. Based on the compositions of examples 2 to 4, acetone (manufactured by Wako pure chemical industries, Ltd.), a water-absorbent resin (polyacrylic acid sodium salt polymer), Talc (manufactured by Nippon Talc Co., Ltd., P-3) and microfibrillar cellulose (manufactured by Daicel FineChem Co., Ltd., Celish (registered trademark)) as a binder were mixed at the ratios shown in Table 4 below to prepare coating liquids. An absorbent body was obtained in the same manner as in example 2-1, except that this coating liquid was used.

[ Table 4]

[ evaluation ]

The thickness of the absorbent core was measured by the above-described method with respect to the absorbent bodies obtained in examples and comparative examples. The bulk density of the absorbent core, the loading rate of the water-absorbent resin, the bending stiffness of the absorbent body, the 1-drop absorption rate, and the warp were measured by the following methods. The results are shown in Table 5 below.

[ bulk Density of absorbent core ]

The mass (g) of the absorbent core was calculated by subtracting the mass of only the base sheet from the mass of the absorbent body at 50mm square. Further, the volume is calculated from the length, width and thickness of the absorbent core. Bulk density (g/cm) of absorbent core³) By dividing the mass (g) of the absorbent core by its volume (cm)³) And then calculated.

[ Loading Rate of Water-absorbent resin ]

The sheet was coated at 50mm square in the center of a 120mm × 100mm substrate sheet, and then dried to obtain an absorber as a measurement target. The absorbent body was held with both ends in the longitudinal direction thereof being 20mm each in a state where the absorbent core of the base sheet was faced downward, bent so that the held both ends were in contact with each other, and thereafter extended so that the base sheet was stretched. These bending and stretching operations were performed 1 time, and 1 second/time for 10 times in succession. The mass before and after bending and extension was measured, and the rate of change in mass was defined as the load carrying rate. The loading rate and the falling rate are expressed by the following formulas.

The amount of detachment (g) — the mass (g) of the absorber before bending and stretching (the mass (g) of the absorber after bending and stretching))

The peel rate (%). was 100 × the amount of peel (g)/(mass of absorbent before bending extension (g))

Loading rate (%) -100-shedding rate (%)

[ bending rigidity of absorbent body ]

As measured by the method described above.

[1 drop absorption Rate ]

As measured by the method described above.

[ warping degree ]

As measured by the method described above.

[ Table 5]

As is clear from the results shown in table 5, the absorbent bodies of the examples have a higher absorption rate, a lower bending stiffness value, and a lower occurrence of warpage than the absorbent body of the comparative example. Further, it was also found that the water-absorbent resins of the absorbent materials of the examples were less likely to fall off. The absorbent material of comparative example 2-1 had a very poor loading rate of the water-absorbent resin.

Examples 3-1 to 3-3

Coating liquids having the compositions shown in table 6 below were prepared. Details of the raw materials and the preparation method of the coating liquid shown in table 6 are as follows. A metal plate having a thickness of 0.3mm and having a lattice opening of 200mm X80 mm was placed on a 280X 120mm substrate sheet, and the prepared coating liquid was applied to the size of the lattice. The sheet coated with the coating liquid was dried in an electric drying oven set to 80 ℃ for about 10 minutes, and thereafter left to stand in a normal temperature environment for about 10 minutes. The absorbent body obtained in this manner was cut into 182mm × 60mm absorbent core sizes to prepare samples for evaluation. As the substrate sheet, WJ35-TRLD (manufactured by Taurus paper (ply)) (grammage: 35 g/m)²). As the water-absorbent resin, a polyacrylic acid sodium salt polymer (manufactured by ST-500D Sanyo chemical industries, Ltd.) was used, and it was pulverized by Lab Mill LM-05 (manufactured by DALTON). The median particle diameter and particle size distribution were adjusted by changing the pulverization conditions (the hammer rotation speed and the screen pore size of the collector) in various ways.

< raw materials >

A water-absorbent resin is dispersed in a liquid in which agents 1 to 3 are dissolved in a solvent, and the obtained liquid is used as a coating liquid.

[ solvent ] ethanol: 95 ℃ Synthetic Alcohol manufactured by Japan Synthetic Alcohol Ltd

[ agent 1] polyvinylpyrrolidone: luviskol (registered trademark) K90, manufactured by BASF corporation

[ agent 2] glycerin: cosmetic concentrated glycerin manufactured by Huawang corporation

[ agent 3] hydroxypropyl cellulose: HPC-H manufactured by Nippon Caoda Ltd

[ Table 6]

[ evaluation ]

With respect to the absorbent obtained in examples, the amount of liquid returned and the flexibility were measured by the following methods. The results are shown in Table 7 below.

[ amount of liquid returned ]

The measurement sample of the absorber was a rectangle of 182mm × 60 mm. The grammage of the water-absorbent resin contained in the absorbent body measurement sample at the time of evaluation was 200g/m². The measurement sample was inserted into a front part used for a light incontinence absorbent pad (for 50cc, manufactured by queen corporation) and 50cc of artificial urine was injected at 5g/sec and left for 2 minutes. The measurement sample after the liquid injection was pressurized at 2.25kPa for 3 minutes via an acrylic plate, and thereafter the pressurization was stopped and left for 30 seconds. Subsequently, a structure obtained by stacking 20 sheets of filter paper No.4A (manufactured by ADVANTEC) was sandwiched between the measurement sample and the front member, and the pressure was applied again at 2.25kPa for 2 minutes. The mass of the filter paper before and after the pressurization was measured, and the amount of the return liquid was calculated according to the following equation.

The amount of return liquid (g) — the mass (g) of the filter paper after liquid injection and pressurization (mass (g) of the filter paper before liquid injection)

[ flexibility ]

The standard for flexibility is obtained by dividing the value of the flexural rigidity of the absorbent body by the grammage of the water-absorbent resin. The bending stiffness of the absorber can be evaluated from the three-point bending load. The smaller the value of the bending load, the higher the flexibility, i.e., the lower the bending rigidity can be judged. The measurement of the three-point bending load was performed in the following manner. The gauges used rigid-flexible gauges (Handle-O-meters).

The measurement sample of the absorbent body was a rectangle of 182mm × 60 mm. The measurement sample is mounted between a pair of plate-like supports. The spacing of the supports was 20 mm. A plate-like pressure-fitting body is pressed into a measurement sample from above the measurement sample mounted between support bodies. The plate-like pressed body had a width of 2mm and a length longer than that of the measurement specimen. Press and pressThe plate-like press-fitting body is located at an intermediate position between the pair of support bodies. The plate-like press-fitting body was press-fitted into the support body by 15mm, and the maximum value of the load generated between the movement amounts was defined as a three-point bending load. The bending stiffness (gf ═ N × 10) was evaluated by measuring a three-point bending load in a direction (CD) orthogonal to the machine direction^-3). Further, the measurement was carried out by dividing the measured bending rigidity by the grammage (g/m) of the water-absorbent resin in the measurement sample²Gsm) to calculate softness. The following is a conversion equation for obtaining flexibility.

Flexibility (Nx 10)^-3(gsm) — (bending stiffness (N × 10)^-3) )/(grammage (gsm) of Water-absorbent resin)

[ Table 7]

	Example 3-1	Examples 3 to 2	Examples 3 to 3
				Amount of reflux (g)	0.5	1.3	2.7
Flexural rigidity (gf)	6.6	9.9	10.8
				Softness (gf/gsm)	0.034	0.049	0.054
Flexibility (Nx 10)^-3/gsm)	0.33	0.48	0.53

As is clear from the results shown in table 7, the absorbent bodies of the examples had a small amount of rewet and high flexibility.

Industrial applicability of the invention

As described above in detail, according to the present invention, an absorbent body having high flexibility and suppressed occurrence of warp can be provided. In particular, when used as an absorbent body for an absorbent article, the absorbent body has good conformability and is less likely to cause discomfort when worn.

Further, according to the present invention, an absorbent body having a high water absorption rate can be provided.

Further, according to the present invention, an absorber with a small amount of return liquid can be provided.

Further, according to the present invention, an absorber that is thin and is suppressed in the occurrence of warpage can be easily manufactured.

Claims

1. An absorbent body having a base sheet and an absorbent core on the base sheet, the absorbent body characterized by:

the content of the water-absorbent resin is 40 to 95 mass% with respect to the absorbent core,

the absorbent core is free of fibrous material.

2. The absorbent of claim 1, wherein:

the non-fibrous water-soluble polymer is at least 1 selected from polyvinylpyrrolidone, polyvinyl butyral and dextrin.

3. The absorbent body according to claim 1 or 2, wherein:

the polyol is more than 1 selected from glycerol, propylene glycol and polyethylene glycol.

4. The absorbent body according to claim 1 or 2, wherein:

the ratio of the area of the absorbent core to the area of the absorbent body is 50% or more and 100% or less.

5. The absorbent body according to claim 1 or 2, wherein:

the thickness of the absorbent core is 0.3mm to 5 mm.

6. The absorbent body according to claim 1 or 2, wherein:

the content of the water-absorbent resin in the absorbent core is 45 mass% or more and 90 mass% or less.

7. The absorbent body according to claim 1 or 2, wherein:

the content of the non-fibrous water-soluble polymer is 0.3 to 4 mass% with respect to the water-absorbent resin.

8. The absorbent body according to claim 1 or 2, wherein:

the content of the polyhydric alcohol is 200 to 1250 mass% relative to the non-fibrous water-soluble polymer.

9. The absorbent body according to claim 1 or 2, wherein:

the absorbent core includes 2 or more layers of laminated construction sections having the same composition or having different compositions.

10. The absorbent of claim 9, wherein:

when the absorbent body is viewed in the width direction thereof, the central region has a multi-layered absorbent core structure, and the side regions on both sides thereof have a single-layered structure.

11. The absorbent body according to claim 1 or 2, wherein:

the substrate sheet is a liquid-permeable fibrous sheet.

12. The absorbent body according to claim 1 or 2, wherein:

the absorbent core is disposed on the entire surface of the substrate sheet.

13. The absorbent body according to claim 1 or 2, wherein:

the absorbent core is formed in a plurality of strips extending in one direction on the base material sheet, and the surface of the base material sheet is exposed in an area between adjacent absorbent cores.

14. The absorbent body according to claim 1 or 2, wherein:

the absorbent core is arranged in a checkered pattern on the base sheet.

15. An absorbent article characterized by:

an absorbent body as claimed in any one of claims 1 to 14.

16. A method for producing an absorbent, characterized by comprising:

preparing a coating material in which a water-absorbent resin, a non-fibrous water-soluble polymer and a polyhydric alcohol are dispersed or dissolved in a solvent, applying the coating material to one surface of a base sheet to form a coated body, drying the coated body to remove volatile components, thereby fixing an absorbent core, which is a dried body of the coated body, to the base sheet,

the coating is free of fibrous material.

17. The method for producing an absorbent body according to claim 16, wherein:

the solvent is a non-aqueous solvent that is free of water.

18. The method for producing an absorbent body according to claim 17, wherein:

the non-aqueous solvent is 1 or more than 2 selected from ethanol, methanol, isopropanol, acetone, methyl ethyl ketone and butyl acetate.

19. The method for producing an absorbent body according to claim 17 or 18, wherein:

the nonaqueous solvent accounts for 30-70 mass% of the coating material.

20. An absorbent body having a base sheet and an absorbent core on the base sheet, the absorbent body characterized by:

the absorbent core comprises (a) a water-absorbent resin, (b) 1 or more of polyvinylpyrrolidone, polyvinyl butyral and dextrin, and (c) 1 or more of glycerin, propylene glycol and polyethylene glycol,

the bending rigidity of the absorber in at least one of the longitudinal direction and the transverse direction is 30g/20mm or less,

the absorbent core is free of fibrous material.

21. An absorbent article characterized by:

having an absorbent body according to claim 20.

22. An absorbent body having a base sheet and an absorbent core on the base sheet, the absorbent body characterized by:

the absorption rate of 1 drop of the absorbent is 30 seconds or less,

the absorbent core is free of fibrous material.

23. An absorbent body having a base sheet and an absorbent core on the base sheet, the absorbent body characterized by:

the absorbent core is free of fibrous material.

24. The absorbent body according to claim 22 or 23, wherein:

the bending rigidity of at least one of the longitudinal direction and the transverse direction of the absorber is 30g/20mm or less.

25. The absorbent body according to claim 22 or 23, wherein:

the porous particles are at least 1 selected from the group consisting of zeolite, perlite, activated carbon, vermiculite, and diatomaceous earth.

26. The absorbent body according to claim 22 or 23, wherein:

among the particle diameters of the water-absorbent resin, the particle diameter D of which the cumulative volume is 50% as measured by a laser diffraction particle size distribution method₅₀Is 150 to 500 μm in diameter.

27. The absorbent body according to claim 22 or 23, wherein:

among the particle diameters of the porous particles, the particle diameter D of 50% of the cumulative volume measured by a laser diffraction particle size distribution method₅₀Is 5 to 100 μm in diameter.

28. The absorbent body according to claim 22 or 23, wherein:

the content of the porous particles is 7.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the water-absorbent resin.

29. An absorbent body having a base sheet and an absorbent core on the base sheet, the absorbent body characterized by:

the median particle diameter of the water-absorbent resin is 150 to 500 [ mu ] m,

the absorbent core is free of fibrous material.

30. The absorbent body of claim 29, wherein:

the water-absorbent resin has a particle size D of 10% of the cumulative volume in the particle size distribution of the water-absorbent resin measured by a laser diffraction particle size distribution method₁₀D represents a particle diameter at 50% of the cumulative volume₅₀D represents a particle diameter at 90% of the cumulative volume₉₀When (D)₉₀-D₁₀)/D₅₀The value of (b) is 0.10 or more and 1.60 or less.

31. The absorbent body of claim 30, wherein: particle diameter of Water-absorbent resin (D)₉₀-D₁₀)/D₅₀The value of (A) is 0.20 or more and 1.50 or less.

32. The absorbent according to any one of claims 29 to 31, wherein:

the median particle diameter of the particle diameters of the water-absorbent resin is 160 μm or more and 450 μm or less.