JP2005015994A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article so structured that water-absorbing resin particles are fastened to fibers uniformly before and after the article absorbs water and the article has high form stability for a long period. <P>SOLUTION: This absorbent article contains the water-absorbing resin particles and the fibers, wherein the absorbent article has a fallen-off gel percentage of ≤ 10% which is defined as (A/B)×100 (A is a weight of water-absorbed and fallen-off gel, measured by making the absorbent article absorb water, applying a load of 3 Kg to the water-absorbed article, vibrating the article at an amplification of 50 cm and a vibration frequency of 80 turn/min for 30 min, and subjecting the fallen-off gel from the article to measurement; and B is a weight of the water-absorbed gel, measured before the article is vibrated). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an absorbent article, and more particularly, to an absorbent article having a high form stability because the water-absorbent resin is less likely to drop off before and after water absorption. The absorbent article of the present invention can be suitably used for sanitary materials such as disposable diapers and sanitary products, industrial materials necessary for absorbing and retaining waste water, and agricultural materials such as freshness-retaining agents such as vegetables and water retention agents. .

  Most commercially available water-absorbing resins are in the form of powder. For example, to be used as sanitary materials such as sanitary napkins and paper diapers, it is necessary to uniformly disperse them on substrates such as tissues, nonwoven fabrics, and cotton. There is. However, the water-absorbent resin powder dispersed by such a method is difficult to fix on the substrate with good stability, and is often partially assembled after dispersion. In addition, when the water-absorbing gel after water absorption is not stably fixed on the base material and easily moves from the base material, a region where the water-absorbing gel does not exist is formed and body fluid or the like has permeated again. There was a problem of leakage.

  As a method for solving these problems, a method of fixing the water-absorbent resin powder on the substrate with a binder is known. However, since the binder adheres to the surface of the water-absorbent resin, the water-absorbing swelling is inhibited and sufficient absorption is achieved. There was a problem that could not be demonstrated. In addition, absorbent materials in which fibers are attached to the surface of a water-absorbent resin have also been proposed (Patent Documents 1 to 3: Japanese Patent Laid-Open Nos. 51-35585, 56-65630, 58-163438). Issue gazette). Before water absorption, the fiber is firmly bonded to the fiber, so that the stability is also fixed. However, these absorbent materials have a problem that the fiber easily deviates from the water-absorbing gel by absorbing the liquid.

  In order to solve these problems, absorbent materials in which fibers are embedded in a water-absorbing resin have been proposed (Patent Documents 4 to 7: JP-A 61-62463, JP-A 63-63723, JP-A-1-135350, JP-B-8-19609). These absorbents are obtained by swelling a water-absorbing resin with water, mixing or kneading fibers, embedding in the water-absorbing resin, drying, and crushing. The obtained absorbent material has a sharp and smooth surface and is partially angular. When pressure is applied to increase the density of the absorbent material in order to cope with the thinning of sanitary materials and the like, the water-absorbing resins collide with each other and corners are formed, and sometimes the water-absorbing resin itself is distorted and cracked. As a result, there arises a problem that the water-absorbent resin that has become free from the fibers leaks from the absorbent article. For this reason, it has been difficult to increase the density of the absorbent material in which the water-absorbent resin is stably fixed. Further, when the water-absorbing gel and the fiber are kneaded and mixed, some of the short fibers are completely embedded in the water-absorbent resin, and the completely embedded fibers do not exhibit the original effect, and only inhibit swelling. Further, since the fiber and the water-absorbent resin are not firmly bound by polymerization, a gap is formed between the fiber and the water-absorbing gel during swelling, and the water-absorbing gel easily moves on the fiber. Further, by kneading the water-absorbing gel under mechanical pressure, the polymer chain is broken and the original water-absorbing performance cannot be obtained. Moreover, since the fiber does not exist on the surface of the water-absorbent resin in this production method, the liquid cannot be held instantaneously, and the diffusion of the liquid also deteriorates.

In order to solve these problems, an absorbent material in which a substantially spherical water-absorbing resin is discontinuously fixed on the surface of non-molded fibers has been proposed (Patent Document 8: Japanese Patent Laid-Open No. 11-93073). . Although this absorbent material certainly solves these problems, when the absorbent material is pressurized because non-molded fibers are bonded via a water-absorbing resin and the fibers form a three-dimensional network. The restoring force due to the fiber connecting the water-absorbent resin is applied to the slab. For this reason, even if sanitary materials etc. that have been made thinner by increasing the density of the absorbent material are manufactured, the package may burst due to the restoring force, or the thickness may increase when the user opens the package. There arises a problem that the shape becomes much larger than the target thickness and the feeling of wearing becomes worse. Further, since the fibers are attached to the water-absorbent resin, there is a problem that the fibers are detached from the gel during the swelling and the water-absorbing gel moves, and the liquid leaks from the absorbent material.
JP 51-35685 A JP 56-65630 A JP 58-163438 A Japanese Patent Laid-Open No. 61-62463 JP 63-63723 A JP-A-1-135350 Japanese Patent Publication No. 8-19609 JP 11-93073 A

  An object of the present invention is to provide an absorbent article in which water-absorbent resin particles are uniformly fixed to fibers through before and after water absorption, and has high form stability over a long period of time. Another object of the present invention is to provide sanitary materials, industrial materials, and agricultural materials having such absorbent articles.

As a result of intensive studies, the present inventors have found that the object can be achieved by an absorbent article containing a water absorbent resin composite having the characteristics described below.
That is, the present invention is an absorbent article containing water-absorbent resin particles and fibers, wherein the gel drop-off rate represented by the following formula (1) is 10% or less.
A
Gel drop-off rate (%) = ――― X 100 (1)
B
(In the above formula, A is the weight of the falling water-absorbing gel after a load of 3 kg is placed on the water-absorbing absorbent article and shaken for 30 minutes at an amplitude of 50 cm and a vibration frequency of 80 times / minute, and B is shaken. It is the weight of the previous water-absorbing gel.)
The present invention also provides sanitary materials, industrial materials, and agricultural materials using the absorbent article.

  In the absorbent article of the present invention, the water-absorbent resin particles are uniformly fixed to the fibers, and even if the water-absorbent resin particles absorb water and become a gel state, they are uniformly fixed to the fibers.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, the absorbent article of the present invention will be described in detail with reference to preferred embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Gel drop-off rate]
The absorbent article of the present invention is characterized in that the gel drop-off rate represented by the above formula (1) is 10% or less. The gel drop-off rate of the absorbent article is preferably 8% or less, and more preferably 5% or less.
Since the gel drop-off rate of the absorbent article of the present invention is 10% or less, it is possible to prevent the gel from coming off from the fibers during swelling and the water-absorbing gel to move, and the liquid from leaking from the absorbent article. In particular, sanitary materials such as diapers have been pointed out in the past as a result of leakage of the liquid once absorbed due to pressure and vibration loads after absorbing the liquid. Can be reduced. As a result, it is possible to provide an absorbent article having a good wearing feeling and high form stability over a long period of time. For this reason, the absorbent article of this invention whose gel drop-off rate is 10% or less has very high practicality.
An absorbent article having a gel drop-off rate of 10% or less can be manufactured by adopting a structure in which fibers are not easily detached from the gel during swelling. For example, if the water absorbent resin composite described below is used, an absorbent article that satisfies the conditions of the present invention can be provided.

[Water absorbent resin composite]
(Structure of water-absorbent resin composite and role of components)
The water absorbent resin composite contained in the absorbent article of the present invention includes one substantially spherical water absorbent resin particle and two or more fibers. One or more fibers contained in the composite are partly embedded in the water-absorbent resin particles and partly exposed from the water-absorbent resin particles. Further, one or more fibers contained in the composite are not embedded in the water-absorbent resin particles, and some of the fibers are adhered to the surface of the water-absorbent resin particles (hereinafter, “ This is referred to as the “water absorbent resin composite of the present invention”). That is, the essential constituent elements of the water-absorbent resin composite of the present invention include water-absorbent resin particles, fibers partially embedded in the water-absorbent resin particles, and the water-absorbent resin particles adhered to the surface of the water-absorbent resin particles. There are three types of fibers that are not embedded in the resin particles. The dry weight ratio between the fibers and the water-absorbent resin particles in the water-absorbent resin composite of the present invention is preferably 1: 1 to 1: 1,000,000, and preferably 1: 2 to 1: 100,000. Is more preferable, and 1: 3 to 1: 10,000 is even more preferable.

(Water absorbent resin and its role)
In the water absorbent resin composite of the present invention, the water absorbent resin plays a role of absorbing liquids such as water, urine, blood and the like according to the purpose of use.
The water absorbent resin used in the water absorbent resin composite of the present invention is a substantially spherical particle. Here, “substantially spherical” has a shape of a true sphere and an ellipsoid as a whole, and may have fine irregularities (that is, wrinkles, protrusions, depressions, etc.) on the surface. Further, there may be voids such as pores and cracks on the surface and inside. Like conventional pulverized water-absorbing resin, if it has an irregular and sharp cut surface, the skin irritation is great, and the sharp cut surface for mechanical addition is lost and fine particles are formed. There is a disadvantage that it occurs. However, the substantially spherical water-absorbing resin particles used in the present invention do not have such a defect. Further, as compared with the amorphous product, it has the advantage that it can be densely packed because it can be close-packed.

(Fiber partially embedded in water-absorbent resin and its role)
The fiber partially embedded in the water absorbent resin plays a role of ensuring the fixability of the water absorbent resin. This fiber also improves the fixability of the water absorbent resin before and after water absorption. That is, the fiber extending from the surface of the water absorbent resin prevents the rotational motion and translational motion of the water absorbent resin during pressing. A part of this fiber is embedded in the water-absorbent resin and does not detach from the water-absorbent resin even after water absorption, so that it can play an important role in fixability after water absorption. The shape of the fiber used may be hollow, side-by-side, or the like in order to increase water conductivity.

When the fiber partially embedded in the water-absorbent resin is composed of a hydrophilic fiber, the fiber exhibits an effect of increasing the water conductivity of the water-absorbent resin. That is, water can be directly introduced into the water absorbent resin through the fiber. In order to exhibit this function more effectively, it is preferable to select and use fibers having high water conductivity described later.
Furthermore, the fibers partially embedded in the water absorbent resin also have a role of ensuring the independence of each water absorbent resin composite. In the polymerization process of the composite precursor, this fiber prevents fusion of the water-absorbent resins due to steric hindrance. That is, the fibers extending from the surface of the water absorbent resin prevent the water absorbent resins being polymerized from contacting each other and prevent the water absorbent resins from fusing together. As a result, each water-absorbing resin composite (precursor) maintains independence, prevents adhesion to the reactor wall in the production process and the treatment process, and secures the opening property described later.

On the other hand, the fibers partially embedded in the water-absorbing resin give appropriate physical entanglement between the water-absorbing composites, and when the plurality of composites are collected into a lump, they are easily separated at their own weight. It also provides form retention that does not occur. That is, the lump made of this water-absorbent resin composite has its own shape retention without adding free fibers or the like. Therefore, this water-absorbent resin composite has the outstanding feature that it can give a lump that has both fiber opening and shape retention.
In addition, the fibers constituting the water-absorbent resin composite give a soft touch and the water-absorbent resin contained in the composite is substantially spherical, so that the composite is pressed even in a dry state. Sometimes it is very soft and suitable for sanitary materials.

(Fiber that adheres to the surface of the water-absorbent resin and is not embedded and its role)
The fibers that are bonded to the surface of the water-absorbent resin but are not embedded in the water-absorbent resin have an effect of securing the fixability of the water-absorbent resin before water absorption. Further, after swelling, the fibers on the surface of the water-absorbent resin have a function of creating a gap between the water-absorbent resins and securing a water flow path. In order to obtain this action, the fibers do not necessarily adhere to the water-absorbent resin after water absorption, but it is preferable that at least the fibers are closely arranged on the surface of the water-absorbent resin. Therefore, it is advantageous that the fiber is bonded to the surface of the water-absorbent resin before water absorption as in the present invention. Further, in some cases, it is preferable to use a fiber having a certain rigidity in order to create a gap between the water-absorbing resins and secure a flow path of water. Further, in combination with the fibers embedded in the water-absorbent resin, there is an effect of securing the water-absorbent resin before water absorption. The shape of the fiber used may be hollow or side-by-side to increase the diffusibility.

  When fibers that are bonded to the surface of the water-absorbent resin but are not embedded in the water-absorbent resin are composed of hydrophilic fibers, the water-absorbent resins come into contact with each other due to swelling of the water-absorbent resin when the fibers absorb water. It shows the effect of preventing the blocking phenomenon that obstructs the water flow path. That is, when absorbing water, it plays a role of uniformly transporting and diffusing water on the surface of each water-absorbing resin. On the other hand, when the fibers that are bonded to the surface of the water-absorbent resin but are not embedded in the water-absorbent resin are composed of hydrophobic fibers, the fiber has a function of improving the diffusibility of water between the water-absorbent resins. Demonstrate. Furthermore, the fibers that are bonded to the surface of the water-absorbent resin but are not embedded in the water-absorbent resin are independent of each water-absorbent resin composite by the same action as the above-mentioned “fiber embedded in the water-absorbent resin”. It has the effect of giving a lump having a soft touch and having a shape retaining property while securing the properties and having the spreadability.

(Desired particle size and fiber length range)
The average particle diameter of the water absorbent resin particles used in the present invention is preferably 50 to 1,000 μm. The average particle size is more preferably from 100 to 900 μm, particularly preferably from 200 to 800 μm. As will be described later, the preferred fiber used in the present invention is one having a fiber length of 50 to 50,000 μm. More preferably, it is 100-30,000 micrometers, More preferably, it is 500-10,000 micrometers. Furthermore, in order to obtain the shape of the present invention, the particle diameter: fiber length ratio is preferably 2: 1 to 1: 1,000. More preferably, it is 1: 1 to 1: 500, particularly preferably 1: 2 to 1: 100.

(Composite effect of each fiber)
Generally, securing the water-absorbent resin is not compatible with securing the water-absorbing ability such as holding ability and water-absorbing ability under pressure. That is, to secure sufficient fixability not only before water absorption but also after water absorption, a strong adhesive force between the water-absorbing resins that surpasses the water absorption expansion force is required even after water absorption. For the time being, the water-absorbing resin itself inhibits water-swelling and does not give sufficient water-absorbing ability. On the other hand, if the adhesive surface is allowed to swell freely in an attempt to ensure water-absorbing ability such as holding ability and water-absorbing ability under pressure, the adhesive surface will be destroyed, and sufficient fixability will not be provided.

In the water absorbent resin composite of the present invention, fibers partially embedded in the water absorbent resin particles and partially exposed from the water absorbent resin particles, and without being embedded in the water absorbent resin particles In addition, fibers that are partially bonded to the surface of the water-absorbent resin particles are essential. In other words, the water-absorbent resin composite having only the former fiber is not sufficient in preventing the blocking phenomenon at the time of water absorption. On the other hand, the water-absorbent resin composite having only the latter fibers does not have sufficient fixability of the water-absorbent resin after water absorption. Therefore, both fibers are indispensable in order to exhibit the above-described action before and after water absorption. The coexistence of both fibers makes it possible to achieve both the securing of the water-absorbing resin, which is originally in an opposing relationship, and the securing of the water absorption capacity. That is, the water-absorbent resin composite has the distinctive feature of ensuring not only the holding ability but also the water-absorbing ability under pressure while securing sufficient fixability before and after water absorption.
The types of both fibers may be the same or different, and are appropriately selected for the purpose of use and the expression of the respective effects.

(Opening property)
One of the characteristics of the water-absorbent resin composite of the present invention is not only that the aggregate of the composite has a fiber-opening property but also a fiber-absorbing resin composite composition containing the composite. It is in the point that can be given. Such characteristics are ensured because each complex is substantially independent. That is, it is desirable that the fibers constituting one composite are not substantially bonded to the other composite. For that purpose, although it depends on production conditions, it is preferable to select the fiber length of the fiber to be used as described above. As shown in the test examples described later, the spreadability can be evaluated by the ease of eyelashes and the state of breakage of the water-absorbent resin particles after eyelashes.

(Form retention)
Further, the water-absorbent resin composite of the present invention is characterized in that not only the aggregate of the composite has shape-retaining properties, but also water-absorbent resin composite compositions containing the composite have shape-retaining properties. There is also a point that you can have. As described above, the binding fibers in the composite give moderate physical entanglement between the respective water-absorbing composites, and when the water-absorbing resin composite composition containing the composite is agglomerated, it is easily at its own weight. Gives form retention so that it does not fall apart.

(Water absorbent resin composite composition)
If necessary, it is possible to produce a water-absorbent resin composite composition by further adding fibers to the water-absorbent resin composite. In this composition, the fiber is a fiber that is not embedded or adhered to the water-absorbent resin. By adding this fiber, flexibility, soft feeling, water conductivity, water permeability, water diffusibility, air permeability and the like can be further improved. Moreover, the opening property of composition itself can also be ensured by selecting the fiber to add suitably.
In general, the composition can be produced by mixing and dispersing fibers appropriately in the produced water-absorbent resin composite. Alternatively, it can also be obtained by supplying, mixing, and dispersing fibers during the production of the water absorbent resin composite by a method that does not substantially contact the water absorbent resin in the progress of polymerization or the water absorbent resin in the water absorbent resin composite.

(Water absorbent resin)
The water-absorbent resin used in the present invention can be produced using the following polymerizable monomer and initiator.
The kind of the polymerizable monomer to be used is not limited as long as it provides a water-absorbing resin. It is particularly preferred to use a polymerizable monomer whose polymerization is initiated by a redox initiator. This polymerizable monomer is usually preferably water-soluble.

  A typical example of such a polymerizable monomer, which is also preferable for use in the present invention, is an aliphatic unsaturated carboxylic acid or a salt thereof. Specific examples include unsaturated monocarboxylic acids or salts thereof such as acrylic acid or salts thereof, methacrylic acid or salts thereof; or unsaturated dicarboxylic acids or salts thereof such as maleic acid or salts thereof, itaconic acid or salts thereof, etc. These may be used alone or in admixture of two or more. Among these, acrylic acid or a salt thereof, and methacrylic acid or a salt thereof are preferable, and acrylic acid or a salt thereof is particularly preferable.

  As the polymerizable monomer that gives the water-absorbent resin used in the present invention, an aliphatic unsaturated carboxylic acid or a salt thereof is preferable as described above. Therefore, an aliphatic unsaturated carboxylic acid or a salt thereof is mainly used as the aqueous solution of the polymerizable monomer. An aqueous solution as a component is preferred. Here, “having an aliphatic unsaturated carboxylic acid or salt thereof as a main component” means that the aliphatic unsaturated carboxylic acid or salt thereof is 50 mol% or more, preferably 80 mol%, based on the total amount of polymerizable monomers. This means that it is included.

As the salt of the aliphatic unsaturated carboxylic acid, water-soluble salts such as alkali metal salts, alkaline earth metal salts, ammonium salts and the like are usually used. The degree of neutralization is appropriately determined according to the purpose. In the case of acrylic acid, it is preferable that 20 to 90 mol% of the carboxyl group is neutralized with an alkali metal salt or an ammonium salt. When the degree of partial neutralization of the acrylic acid monomer is less than 20 mol%, the water absorption ability of the water absorbent resin to be produced tends to be remarkably lowered.
For the neutralization of the acrylic acid monomer, alkali metal hydroxides, bicarbonates, etc. or ammonium hydroxide can be used, but preferred are alkali metal hydroxides. Sodium and potassium hydroxide are mentioned.

In the present invention, in addition to the aliphatic unsaturated carboxylic acid, polymerizable monomers copolymerizable with these, for example, (meth) acrylamide, (poly) ethylene glycol (meth) acrylate, 2-hydroxyethyl ( Although it is a meth) acrylate or a low water-soluble monomer, alkyl acrylates such as methyl acrylate and ethyl acrylate may be copolymerized in an amount that does not deteriorate the performance of the resulting water absorbent resin. . In the present specification, the term “(meth) acryl” means both “acryl” and “methacryl”.
Of these polymerizable monomers, those that give a water-absorbing resin are not used as auxiliary components for the aliphatic unsaturated carboxylic acid or its salt, but as the main monomer of an “aqueous solution of a polymerizable monomer that gives a water-absorbing resin”. You can also

  An aliphatic unsaturated carboxylic acid or a salt thereof, particularly acrylic acid or a salt thereof may form a self-crosslinked polymer by itself, but a crosslinker can be used in combination to actively form a crosslinked structure. . When a crosslinking agent is used in combination, the water absorption performance of the water absorbent resin that is generally produced is improved. As the crosslinking agent, it can react with a polyvinyl compound copolymerizable with the polymerizable monomer, for example, N, N′-methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylates, and carboxylic acid. Water-soluble compounds having two or more functional groups, for example, polyglycidyl ethers such as ethylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether are preferably used. Of these, N, N'-methylenebis (meth) acrylamide is particularly preferred. The amount of the crosslinking agent used is 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight, based on the charged amount of the polymerizable monomer.

  The concentration of the polymerizable monomer in the polymerizable monomer aqueous solution containing the above-mentioned aliphatic unsaturated carboxylic acid or a salt thereof as a main component is 20% by weight or more, preferably 25% by weight or more. When the concentration is less than 20% by weight, the water absorption ability of the water absorbent resin after polymerization tends to be insufficient. The upper limit is preferably about 80% by weight from the handling of the polymerization reaction solution.

As the polymerization initiator used in the present invention, those used in aqueous solution radical polymerization can be used. Examples of such initiators include inorganic and organic peroxides such as ammonium and alkali metals, particularly persulfates such as potassium, hydrogen peroxide, t-butyl peroxide, acetyl peroxide, and the like.
Furthermore, initiators known as azo compounds can also be used. For example, 2,2′-azobis (2-amidinopropane) dihydrochloride, which shows water solubility to some extent, can be mentioned.
Polymerization is initiated by decomposition of the radical polymerization initiator. A commonly known technique is pyrolysis. Often, a polymerization initiator that has not been heated is added to the polymerizable monomer in the reaction solution that has been heated to the decomposition temperature of the polymerization initiator in advance to initiate the polymerization. Belongs.

The initiator preferably used in the present invention is a combination of an oxidizing agent and a reducing agent that forms a water-soluble redox system to some extent.
Examples of the oxidizing agent include hydrogen peroxide, persulfates such as ammonium persulfate and potassium persulfate, t-butyl hydroperoxide, cumene hydroperoxide, ceric salt, permanganate, chlorite, Examples include hypochlorite. Among these, hydrogen peroxide is particularly preferable. The amount of these oxidizing agents used is 0.01 to 10% by weight, preferably 0.1 to 2% by weight, based on the polymerizable monomer.

  The reducing agent is capable of forming a redox system with the oxidizing agent, specifically, sulfites such as sodium sulfite and sodium bisulfite, sodium thiosulfate, cobalt acetate, copper sulfate, ferrous sulfate, L- Examples include ascorbic acid or L-ascorbic acid alkali metal salts. Among these, L-ascorbic acid or L-ascorbic acid alkali metal salt is particularly preferable. The amount of these reducing agents used is 0.001 to 10% by weight, preferably 0.01 to 2% by weight, based on the polymerizable monomer.

(fiber)
As the fiber, synthetic fiber, natural fiber, semi-synthetic fiber, inorganic fiber and the like can be used.
The fiber to be used is selected according to the intended use of the water absorbent resin composite and the role of each fiber constituting the water absorbent resin composite. For example, when the composite is used for a water-absorbent article, it is preferable to select a highly hydrophilic fiber such as pulp, rayon, cotton, regenerated cellulose and other cellulosic fibers. Further, a fiber having high hydrophilicity is preferable from the viewpoint of water conductivity. Especially for sanitary materials, pulp is also preferred from the viewpoint of good touch. Although there is no limitation in particular as a pulp kind, groundwood pulp, etc. as mechanical pulp; semi-chemical pulp, chemical ground pulp, etc. as chemical mechanical pulp; sulfite pulp, sulfate pulp, soda pulp, nitric acid method pulp, chlorine method pulp, etc. as chemical pulp; Examples of recycled pulp include mechanically crushed or pulverized paper made once by paper making, or recycled recycled paper pulp that is mechanically crushed or pulverized wastepaper.
Further, in view of environmental problems, synthetic fibers such as biodegradable polylactic acid fibers and aliphatic polyesters may be used instead of synthetic fibers that are not biodegradable.

  Each fiber is preferably firmly bonded to the water-absorbent resin both before and after water absorption from the viewpoint of the fixability of the water-absorbent resin. In general, it is known that adhesion between materials having high affinity is strong. From the viewpoint of securing the adhesive strength, it is also preferable in the present invention to use fibers having high affinity with the water-absorbent resin. A fiber having a high affinity with a water-absorbing resin that is generally hydrophilic is a hydrophilic fiber. The affinity between the hydrophilic water-absorbent resin and the fibers used can be regarded as a quantitative measure based on the contact angle of water on the surface of the fiber material. That is, the smaller the contact angle on the surface of the water fiber material, the higher the affinity between the water-absorbing resin and the fiber, and the greater the adhesive strength. Conversely, a large contact angle means a low affinity and a small adhesive force. In this sense, the contact angle of water on the surface of the fiber material is preferably 60 ° or less, more preferably 50 ° or less, and most preferably 40 ° or less. The contact angle depends on the shape of the fiber material to be measured and the smoothness of the surface. The contact angle in the present invention means a contact angle with respect to distilled water when the fiber material is placed on a smooth surface such as a film or sheet, and can be measured using an apparatus described later.

  The surface of the hydrophobic fiber may be made hydrophilic so that the contact angle on the surface of the fiber material is 60 ° or less. Therefore, it can be modified with one or more known anionic, cationic or nonionic surfactants. For example, it can be hydrophilized by a method of spraying and applying directly to hydrophobic fibers, a method of applying during or after formation of fibers or nonwoven fabrics, a method of adding fibers to a polymer composition before spinning.

  On the other hand, from the viewpoint of water permeability and water diffusibility, hydrophobic fibers can be used in combination with hydrophilic fibers. For example, polyester, polyethylene, polypropylene, polystyrene, polyamide, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyurea, polyurethane, polyfluoroethylene, polycyan Vinylidene chloride fibers can be used. For example, a hydrophilic fiber is selected as a fiber partly embedded in the water absorbent resin particles and partly exposed from the water absorbent resin particles, and the fibers are not embedded in the water absorbent resin particles. Hydrophobic fibers can be selected as the fibers that are partly bonded to the surface of the water-absorbent resin particles. If such an aspect is employ | adopted, a hydrophobic fiber will exhibit the function to improve the diffusibility of the water between water absorbing resins.

  Further, two or more fiber types can be used in combination. At that time, the fiber type and the mixing ratio depend on the use of the water-absorbent resin composite composition, but can be selected within a range not impeding water permeability. Further, in the water absorbent resin composite composition, the mixing ratio of fibers can be given a gradation, or each fiber can be unevenly distributed.

From the viewpoint of preventing blocking, it is also important to select a fiber in consideration of the rigidity and fiber diameter of the fiber described later.
Preferred fibers for use in the present invention are those having an average fiber length of 50 to 50,000 μm. More preferably, it is 100-30,000 micrometers, More preferably, it is 500-10,000 micrometers. If the fiber length is longer than 50,000 μm, the fibers adhere to a plurality of water-absorbent resins, and the independence of each water-absorbent resin composite cannot be ensured, making it difficult to open a composition containing this composite Tend. On the other hand, when the fiber length is smaller than 50 μm, embedding and adhesion to the water-absorbing resin tend to be difficult.
In order to obtain a desired shape of the water absorbent resin composite, the ratio of the water absorbent resin particle diameter: fiber length is preferably 2: 1 to 1: 1000. More preferably, it is 1: 1 to 1: 500, and particularly preferably 1: 2 to 1: 100.

  In the present invention, fibers having a fiber diameter of 0.1 to 500 dtex are preferable, fibers having a diameter of 0.1 to 100 dtex are more preferable, even more preferably 1 to 50 dtex, and particularly preferably 1 to 10 dtex. . When the fiber diameter is larger than 500 dtex, not only is the fiber rigidity too high, it becomes difficult to embed and adhere to the water-absorbent resin, but compression molding becomes difficult, which may be undesirable for thinning. In addition, the use of sanitary products may be stiff or tingling, and the touch may not be preferable. On the other hand, if the fiber diameter is less than 0.1 dtex, the above-described water conductivity and diffusibility may not be ensured because the fiber is too thin. Moreover, since rigidity is insufficient, there are cases in which it is not possible to prevent such a situation.

Further, as the fibrous material, a non-linear fiber such as a curl shape or a split hair shape can also be used.
Furthermore, synthetic fibers such as polylactic acid fibers and aliphatic polyesters having biodegradability may be used instead of synthetic fibers having no biodegradability in consideration of environmental problems.
From the above viewpoints, the fiber type, fiber length, fiber diameter, and fiber shape are appropriately selected.

It is preferable that the fibers are dispersed as evenly as possible. Generally, fibers tend to form a fiber lump due to entanglement, but the apparent fiber lump diameter is preferably 20 mm or less, more preferably 10 mm or less, and most preferably 5 mm or less. Of course, it is needless to say that it is preferable to be independent for each single fiber. In general, a technique called opening is used to ensure uniformity. “Opening” includes the concept of both defibration and fiberization. Defibration includes tearing a sheet-like material such as nylon into strips or fibers. In addition, the fiberization includes cutting the base paper-like cellulose into pulp.
As a specific technique, “Fiber Handbook (Processing)” (Fiber Society of Japan, Maruzen, 1969), page 18 and below, cotton spinning type, eyelash type, woolen type, hemp type, silk spinning type or A rotary blade crusher, a hammer crusher, a pulp defibrator or the like can be used as appropriate. It is also possible to charge the fibers known as flocking and effectively disperse the fibers one by one using the electrostatic repulsion between the fibers and uniformly disperse them.

[Water-absorbent resin composite composition]
(Constitution)
The water absorbent resin composite composition of the present invention is characterized by containing the above water absorbent resin composite. For example, the water-absorbent resin composite in which the water-absorbent resin composite and the fibers are mixed in an arbitrary composition by mixing the deposited water-absorbent resin composite or the above-described opened and independent water-absorbent resin composite and the fiber. A body composition can be produced. The fiber to be mixed is not particularly limited. For example, the water absorbent resin composite composition of the present invention may contain one or more fibers that are not embedded or adhered to the water absorbent resin.

  At this time, it is preferable that the dry weight ratio of “fibers that are not embedded or adhered to the water absorbent resin” and the water absorbent resin is 90:10 to 5:95, and 90:10 to 35:75. More preferably, it is more preferably 85:15 to 35:65. If the dry weight ratio of “fibers that are not embedded or adhered to the water-absorbent resin” and the water-absorbent resin is more than 90:10, the effect of the water-absorbent resin is hardly exhibited, and the bulk density May become smaller. On the other hand, if the weight ratio is less than 5:95, further improvements in flexibility, soft feeling, water conductivity, water permeability, water diffusibility, air permeability, and the like may not be sufficient.

The water-absorbent resin composite composition of the present invention may contain a composite containing fibers and a water-absorbent resin in addition to the water-absorbent resin composite of the present invention. For example, the water absorbent resin composite composition of the present invention is a water absorbent resin composite comprising one or more water absorbent resin particles and one or more fibers, wherein the water absorbent resin particles are substantially spherical, One or more of the fibers are partially embedded in the resin particles and partially exposed from the resin particles, and all the fibers are bonded to the surface of the resin particles. May contain no water-absorbent resin composite. Further, the water-absorbent resin composite comprising one or more water-absorbing resin particles and one or more fibers, wherein the water-absorbing resin particles are substantially spherical, and the one or more fibers are part of the fibers. The fibers may be bonded to the surface of the resin particles, and each of the fibers may include a water-absorbing resin composite that is not embedded in the resin particles. The water absorbent resin composite composition of the present invention preferably contains 0.1 or more, more preferably 0.2 or more, and more preferably 0.3 or more by weight fraction of the water absorbent resin composite of the present invention. Is more preferable. The water absorbent resin composite composition of the present invention preferably has a bulk density of 0.20 to 1.10 g / cm ³ , more preferably 0.30 to 0.85 g / cm ³ , and More preferably, it is 40-0.85 g / cm < ³ >.

(Fiber that is not embedded or bonded to water-absorbent resin)
As the fiber, synthetic fiber, natural fiber, semi-synthetic fiber, inorganic fiber and the like can be used.
The fiber to be used is selected according to the intended use of the water absorbent resin composite composition. For example, when the composition is used for an absorbent article, it is preferable to select a highly hydrophilic fiber such as pulp, rayon, cotton, regenerated cellulose or other cellulosic fibers. Further, a fiber having high hydrophilicity is preferable from the viewpoint of water conductivity. Especially for sanitary materials, pulp is preferred because of its good touch.
On the other hand, hydrophobic fibers can also be used. For example, polyester, polyethylene, polypropylene, polystyrene, polyamide, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyurea, polyurethane, polyfluoroethylene, polycyan This is a vinylidene fluoride fiber. By using these hydrophobic fibers, water permeability and water diffusibility in the composition can be improved.

In addition, there is no restriction | limiting in particular about the affinity with the water absorbing resin of the fiber to be used, or the affinity with the water absorbing resin composite.
The fiber type to be used may be the same as or different from the above-mentioned “fiber embedded or adhered to the water-absorbent resin”. For example, hydrophilic fibers can be selected as “fibers embedded or bonded in water-absorbing resin”, and hydrophobic fibers can be selected as “fibers that are not embedded or bonded in water-absorbing resin”. . If such an aspect is employ | adopted, a hydrophobic fiber will exhibit the function to improve the diffusibility of the water between water absorbing resin composites.
The mixing ratio in the case of using two or more fiber types in combination is preferably selected within a range that does not impair the water permeability in the absorbent article. A gradation may be given to the mixing ratio of two kinds of fibers, or each fiber may be unevenly distributed.

From the viewpoint of preventing blocking, it is also important to select a fiber in consideration of the rigidity and fiber diameter of the fiber described later.
A fiber having a fiber length of 50 to 100,000 μm is preferable as a fiber that is neither embedded nor bonded to the water-absorbent resin. More preferably, it is 100-50,000 micrometers, More preferably, it is 500-20,000 micrometers. When the fiber length is longer than 100,000 μm, it may be difficult to open the composition. On the other hand, when the fiber length is less than 50 μm, the mobility of the fiber itself is large, so that there is a problem that the fiber leaks from the composition.

The fiber that is not embedded or adhered to the water-absorbent resin preferably has a fiber diameter of 0.1 to 500 dtex, more preferably 0.1 to 100 dtex, and even more preferably 1 ˜50 dtex, particularly preferably 1 to 10 dtex. When the fiber diameter is larger than 500 dtex, not only is the rigidity of the fiber too large and mixing with the water-absorbent resin composite becomes difficult, but compression molding becomes difficult, which may be undesirable for thinning. In addition, the use of sanitary products may be stiff or tingling, and the touch may not be preferable. On the other hand, if the fiber diameter is less than 0.1 dtex, the above-described water conductivity and diffusibility may not be ensured because the fiber is too thin. Moreover, since rigidity is insufficient, there are cases in which it is not possible to prevent such a situation.
From the above viewpoints, the fiber type, fiber length, and fiber diameter are appropriately selected.

(Production method)
The method for producing the water absorbent resin composite of the present invention is not particularly limited as long as it is a method capable of producing a water absorbent resin composite that satisfies the conditions described in the claims.

In a preferred production method, a redox polymerization initiator is disposed in an aqueous solution of a polymerizable monomer that gives a water-absorbing resin, for example, an aqueous solution of a polymerizable monomer that contains an aliphatic unsaturated carboxylic acid or a salt thereof as a main component. Polymerization of the polymerizable monomer is started, and the reaction mixture containing the polymerizable monomer and the produced polymer after the start of the reaction is formed into droplets in the gas phase, and contacted with the dispersed fibers supplied in the gas phase, It becomes a water absorbent resin composite precursor, completes polymerization, and is recovered as a water absorbent resin composite.
One preferred method for polymerizing droplets in the gas phase is a first liquid comprising a polymerizable monomer aqueous solution containing one of an oxidizing agent and a reducing agent constituting the redox polymerization initiator and the other of the redox polymerization initiator. The polymerization is started by mixing in a gas phase a second liquid comprising an aqueous solution containing a polymerizable monomer as required.

  As a specific means, for example, the first liquid and the second liquid are ejected from separate nozzles so that the crossing angle between the liquids flowing out from the nozzles is an angle of 15 degrees or more and collide in a liquid column state. There is a way. In this way, by causing the two liquids to collide with each other with an intersecting angle, a part of the outflow energy from the nozzle is used for mixing. The crossing angle between the first liquid and the second liquid flowing out from each nozzle is appropriately selected according to the properties of the polymerizable monomer to be used, the flow rate ratio, and the like. For example, if the linear velocity of the liquid is high, the crossing angle can be reduced.

In this case, the temperature of the first liquid is usually from room temperature to about 60 ° C., preferably from room temperature to about 40 ° C., and the temperature of the second liquid is also usually from room temperature to about 60 ° C., preferably from room temperature to about 40 ° C. ° C.
In this way, the respective aqueous solutions ejected from the nozzles collide in a liquid column state to combine both liquids. After the coalescence, a liquid column is formed and the state is maintained for a certain period of time, but the liquid column is then disassembled into droplets. The generated droplets undergo polymerization in the gas phase.

The size of the droplet is about 5 to 3,000 μm in diameter. In order for the polymerization of the droplets to proceed and contact with the fibers to form a suitable water absorbent resin composite, the size of the droplets is particularly preferably in the range of 50 to 1,000 μm. The spatial density of the droplets in the reactor is preferably 10 to 10,000 g / m ³ . If this upper limit is exceeded, a water-absorbing resin that does not contact the fiber is generated, and if it is less than this lower limit, a fiber that does not contact the water-absorbing resin is generated, resulting in a problem that the yield of the water-absorbing resin composite is relatively lowered. .

  The gas phase gas that provides a reaction field for starting the polymerization and forming droplets during the polymerization is preferably inert to the polymerization such as nitrogen, helium, carbon dioxide, etc., but may be air. Also, there is no particular limitation on the humidity in the gas, including the case of only water vapor, but if the humidity is too low, the water in the polymerizable monomer aqueous solution evaporates before the polymerization proceeds, and the polymerizable monomer precipitates, As a result, there is a possibility that the polymerization rate is remarkably reduced or the polymerization is stopped midway. The temperature condition of the gas is room temperature or higher and 150 ° C. or lower, desirably 100 ° C. or lower. The gas flow direction may be either counter-current or co-current with respect to the liquid column and the traveling direction of the liquid droplets. If it is necessary to increase the viscosity of the droplets and thus increase the viscosity of the droplets, countercurrent (antigravity direction) is better.

(Fiber supply port)
The conversion ratio of the polymerizable monomer in the droplet when the droplet and the fiber are brought into contact with each other is preferably in the range of 0 to 90%. More preferably, it is 0 to 70%, and most preferably in the range of 0 to 60%. At a conversion rate of 90% or more, there is a possibility that the fibers used are not embedded or adhered to the water-absorbent resin.
The water-absorbent resin composite of the present invention having the above structure can also be produced by supplying fibers in a reaction field at a stage where the conversion ratio of the polymerizable monomer is equal, but two or more stages where the conversion ratio of the polymerizable monomer is different. It is preferable to produce the fiber by supplying the fiber in the reaction field. For this purpose, it is preferable to supply fibers from a plurality of supply ports. That is, when the fiber is to be partially embedded in the water-absorbent resin, it is desirable to contact the polymerizable monomer at a stage where the conversion rate of the polymerizable monomer is relatively low. When it is intended to adhere to the resin surface, it is desirable to make contact at a stage where the conversion rate of the polymerizable monomer is relatively high.

  In order to produce both fibers that are partially embedded in the water-absorbent resin and fibers that are not embedded and bonded to the surface of the water-absorbent resin, the polymerizability in the contact field between the respective fibers and the polymerizable monomer The difference in monomer conversion is preferably in the range of 10% to 80%. More preferably, it is 10 to 70%, and most preferably 10 to 60%. The conversion rate in each contact field is appropriately determined according to the polymerizable monomer species, fiber species, and the like.

(Fiber transport method)
A generally known transport method can be used as a method for supplying fibers to contact the droplets during polymerization. The spatial density of the fibers in the reactor is preferably in the range of 0.005 to 1000 g / m ³ when the fibers are partially embedded in the water absorbent resin. If this upper limit is exceeded, fibers that are not embedded in the water-absorbent resin composite will be generated, and if it is below this lower limit, a water-absorbent resin that does not embed the fibers will be generated, and the yield of the water-absorbent resin composite will be relatively reduced. Problems arise. In order to supply the fibers as finely and uniformly as possible, it is preferable to supply the fibers as a mixed phase flow with gas. As the gas used here, those mentioned above as the gas phase gas that gives the reaction field can be used. Among these, air is preferable from the viewpoint of economics and reduction of environmental load.

The weight mixing ratio of the fiber and gas supplied as a multiphase flow is preferably 1: 1 or less, and the linear velocity of the gas is preferably in the range of 1 to 50 m / sec. When the linear velocity of the gas exceeds 50 m / sec, the locus of the reaction mixture during polymerization in the reaction field may be disturbed, and adhesion to the inner surface of the reactor may become a problem. On the other hand, if it is less than the lower limit, fiber uniformity may not be ensured.
The temperature of the gas supplied as a multiphase flow is desirably selected within a range that does not significantly inhibit the polymerization. Specifically, from this point of view, the temperature is from room temperature to 150 ° C., preferably 100 ° C. or less. From the viewpoint of fiber transportation, it is preferable that the humidity in the gas is low, but if the humidity is too low, the humidity in the reactor is lowered, and the water in the polymerizable monomer aqueous solution evaporates before the polymerization proceeds. As a result, the monomer is precipitated, and as a result, the polymerization rate is remarkably reduced, or the polymerization may be stopped in the middle.

(Opening of water-absorbent resin composite)
The water absorbent resin composite is recovered as a deposit. Since each water-absorbent resin composite is independent of each other, it can be easily opened. For the opening, the opening method described in the description of the fibers can be used as appropriate, but an apparatus and conditions that do not damage the water-absorbent resin due to mechanical impact are preferable.

(Other additional processes)
In the production of the water-absorbent resin composite of the present invention, as other additional steps, a residual monomer treatment step, a surface cross-linking step, a catalyst, a reducing agent, a deodorant, a human urine stabilizer, in order to provide other functions, An additive addition step such as an antibacterial agent may be added.
Examples of the method for treating the residual monomer include 1) a method of proceeding polymerization of the residual monomer, 2) a method of introducing the residual monomer to another derivative, and 3) a method of removing the residual monomer.

Examples of the method of proceeding the polymerization of the residual monomer of 1) include, for example, a method of further heating the composite of the water-absorbent resin and fiber, and heating after adding a catalyst or catalyst component that promotes the polymerization of the residual monomer to the water-absorbent resin. And a method of irradiating with ultraviolet rays, a method of irradiating with electromagnetic radiation or particulate ionizing radiation, and the like.
In the method of further heating the water absorbent resin composite, the water absorbent resin composite is subjected to a heat treatment at 100 to 250 ° C. to polymerize monomers remaining in the water absorbent resin composite.

  The method of adding a catalyst or catalyst component that promotes the polymerization of residual monomer to the water-absorbent resin composite is that, for example, when polymerization is performed using a redox polymerization initiator, the radical generator may remain. Since there are many, what is necessary is just to provide a reducing agent solution to water absorbing resin. As the reducing agent, sodium sulfite, sodium hydrogen sulfite, L-ascorbic acid or the like used as a redox polymerization initiator may be used. Usually, these are given to the water-absorbent resin composite as an aqueous solution of 0.5 to 5% by weight. To do. The amount of the reducing agent applied is preferably 0.1 to 2% by weight based on the dry resin. Application | coating of a reducing agent solution can be performed by arbitrary methods, such as spraying using an atomizer and immersing in a reducing agent solution. The water-absorbent resin composite to which the reducing agent has been added is then heated to polymerize the monomer. Heating may be performed, for example, at 100 to 150 ° C. for about 10 to 30 minutes. Although the water content of the water-absorbent resin composite is reduced by this heating, if the water content is high, the water-absorbent resin composite is further dried with a dryer to obtain a product water-absorbing material.

  In the method of irradiating the water-absorbent resin composite with ultraviolet rays, an ordinary ultraviolet lamp may be used. Irradiation intensity, irradiation time and the like vary depending on the type of fiber used, the amount of residual monomer impregnation, etc. The lamp is 10 to 200 W / cm, preferably 30 to 120 W / cm, the irradiation time is 0.1 second to 30 minutes, and the lamp-complex distance is 2 to 30 cm. The water content in the water-absorbent resin composite at this time is generally 0.01 to 40 parts by weight, preferably 0.1 to 1.0 parts by weight, based on 1 part by weight of the polymer. Is done. A water content of less than 0.01 parts by weight or more than 40 parts by weight is not preferable because it significantly affects the reduction of residual monomers. As an atmosphere when irradiating with ultraviolet rays, any of vacuum, presence of an inorganic gas such as nitrogen, argon, helium, or air can be used. The irradiation temperature is not particularly limited, and the object can be sufficiently achieved at room temperature. There is no restriction | limiting in particular also in the ultraviolet irradiation apparatus to be used, Arbitrary methods, such as the method of irradiating for a fixed time for a fixed time, or the method of irradiating continuously with a belt conveyor, can be used.

  In the method of irradiating the water absorbent resin composite with radiation, high energy radiation such as accelerated electrons or gamma rays is used. The dose to be irradiated varies depending on the amount of residual monomer in the composite, the amount of water, and the like, but is generally 0.01 to 100 megarads, preferably 0.1 to 50 megarads. When the dose exceeds 100 megarads, the amount of water absorption becomes extremely small. When the dose is less than 0.01 megarad, the water absorption capacity and the water absorption speed intended in the present invention are large, and it is difficult to obtain a particularly small residual monomer. The water content of the water-absorbent resin composite at this time is generally 40 parts by weight or less, preferably 10 parts by weight or less, based on 1 part by weight of the polymer. If the amount of water exceeds 40 parts by weight, the effect of improving the water absorption rate is small, and particularly the reduction of the residual monomer is significantly affected. As an atmosphere for irradiating the composite with high energy radiation, any of vacuum, presence of an inorganic gas such as nitrogen, argon, helium, or air can be used. A preferable atmosphere is air. When irradiation is performed in the air, the water absorption capacity and the water absorption speed are increased, and the residual monomer is particularly reduced. Moreover, there is no restriction | limiting in particular in irradiation temperature, The objective can fully be achieved at room temperature.

  Examples of the method of introducing the residual monomer of 2) to other derivatives include a method of adding an amine, ammonia and the like, and a method of adding a reducing agent such as bisulfite, sulfite and pyrosulfite.

  Examples of the method 3) for removing the residual monomer include extraction with an organic solvent and distillation. In the method of extracting with an organic solvent, the water-absorbent resin composite is immersed in a water-containing organic solvent to extract and remove residual monomers. As the water-containing organic solvent, ethanol, methanol, acetone or the like can be used, and the water content is preferably 10 to 99% by weight, particularly preferably 30 to 60% by weight. Generally, the higher the water content, the higher the ability to remove the residual monomer. However, when a water-containing organic solvent having a high water content is used, the energy consumption in the subsequent drying step increases. The time for immersing the complex in the water-containing organic solvent is usually about 5 to 30 minutes, and it is also preferable to adopt a means for promoting the extraction of the residual monomer such as shaking the complex. After the immersion treatment, it is usually treated with a dryer and dried.

  As a method for distilling off the residual monomer, there is a method of treating the composite with superheated steam or a steam-containing gas. For example, the residual monomer in the water-absorbent resin can be reduced by heating saturated steam at 110 ° C. to 120 to 150 ° C. and bringing it into contact with the composite as superheated steam. In this method, when water in the water-absorbent resin evaporates as water vapor, it is considered that residual monomers are vaporized at the same time and escape from the water-absorbent resin. According to this method, it is possible to both remove the residual monomer and dry the product.

(Surface cross-linking)
In addition, for the purpose of improving the water absorption performance, the surface of the water absorbent resin can be crosslinked with a crosslinking agent. In general, it is known to improve the properties of resin particles by applying an appropriate amount of moisture together with a crosslinking agent to the surface of powdered water-absorbent resin particles, and then heating to crosslink the surface. As a result of the formation of a crosslinked structure, it is considered that the shape can be maintained without inhibiting the swelling when water is absorbed and swollen. In this step, first, a solution of a surface crosslinking agent is applied to the water absorbent resin composite. As the surface cross-linking agent, polyfunctional compounds that can be copolymerized with polymerizable monomers such as N, N′-methylenebis (meth) acrylamide and (poly) ethylene glycol di (meth) acrylate, (poly) ethylene glycol diglycidyl ether, etc. A compound having a plurality of functional groups capable of reacting with the carboxylic acid group is used. These surface crosslinking agents are usually used in an amount of 0.1 to 1% by weight, preferably 0.2 to 0.5% by weight, based on the water absorbent resin composite. These surface cross-linking agents are diluted with water, ethanol, methanol or the like so as to be uniformly applied to the entire water-absorbent resin composite, and are 0.1 to 1% by weight, particularly 0.2 to 0.5%. It is preferably used as a weight percent solution. The application of the cross-linking agent solution is usually preferably carried out by spraying the cross-linking agent solution onto the water-absorbent resin composite using a sprayer or applying the cross-linking agent solution with a roll brush. In addition, after providing a crosslinking agent solution excessively, you may make it remove excessive surplus crosslinking agent solution by squeezing lightly to such an extent that a resin particle is not crushed with a pressing roll, or blowing a wind. The application of the crosslinking agent solution may be performed at room temperature. The water-absorbent resin composite to which the cross-linking agent solution is applied is then heated to cause a cross-linking reaction to selectively form a cross-linked structure on the surface of the water-absorbent resin. The conditions for the crosslinking reaction may be appropriately selected depending on the crosslinking agent used, but the reaction is usually carried out at a temperature of 100 ° C. or more for 10 minutes or more. In the present invention, the unsaturated carboxylic acid polymer crosslinked product is preferable as the water absorbent resin, and the partially neutralized acrylic acid polymer crosslinked product is particularly preferable.

(Additive)
Various additives can be added to the water-absorbent resin composite or the water-absorbent resin composite composition in order to impart a desired function depending on the intended application. Examples of these additives include a stabilizer for preventing polymer degradation and alteration due to the liquid to be absorbed, an antibacterial agent, a deodorant, a deodorant, a fragrance, and a foaming agent.

  Among these, as a stabilizer to prevent polymer degradation and alteration due to the liquid to be absorbed, excrement (ie, human urine, feces), body fluid (human fluid, menstrual blood, fluid such as secretory fluid) decomposition and alteration of the water absorbent resin Stabilizers to prevent are mentioned. JP-A-63-118375 discloses a method for containing an oxygen-containing reducing inorganic salt and / or an organic antioxidant in a polymer, JP-A-63-153060 discloses a method for containing an oxidizing agent, JP 63-127754 A contains an antioxidant, JP 63-272349 A contains a sulfur-containing reducing agent, JP 63-146964 contains a metal chelating agent. JP-A 63-15266 discloses a method containing a radical chain inhibitor, JP-A 1-275661 discloses a phosphinic acid group- or phosphonic acid group-containing amine compound or a salt thereof, Japanese Laid-Open Patent Application No. 64-29257 discloses a method of containing a polyvalent metal oxide, Japanese Patent Application Laid-Open No. 2-255804, Japanese Patent Application Laid-Open No. 3-179008 discloses polymerization. A method in which the coexistence of a water-soluble chain transfer agents have been proposed. All of these can be used in the present invention. In addition, JP-A-6-306202, JP-A-7-53884, JP-A-7-62252, JP-A-7-113048, JP-A-7-145326, JP-A-7-145263, The materials and methods described in JP-A-7-228788 and JP-A-7-228790 can also be used. Specific examples include potassium oxalate titanate, tannic acid, titanium oxide, phosphinic acid amine (or salt thereof), phosphonic acid amine (or salt thereof), metal chelate and the like. Of these, stabilizers against human urine, human blood, and menstrual blood are sometimes referred to as human urine stabilizer, human blood stabilizer, and menstrual blood stabilizer, respectively.

  Antibacterial agents are used in order to prevent spoilage due to the absorbed liquid. As antibacterial agents, for example, “New development of bactericidal / antibacterial technology”, pages 17-80 (Toray Research Center (1994)), “Testing / evaluation methods and product design of antibacterial / antifungal agents”, pages 128-344 (NTT) S (1997)), Japanese Patent No. 2760814, Japanese Unexamined Patent Publication No. 39-179114, Japanese Unexamined Patent Publication No. 56-31425, Japanese Unexamined Patent Publication No. 57-25813, Japanese Unexamined Patent Publication No. 59-189854, JP 59-105448, JP 60-158861, JP 61-181532, JP 63-135501, JP 63-139556, JP 63-156540. JP-A-64-5546, JP-A-64-5547, JP-A-1-153748, JP-A-1-221242, JP-A-2-253. No. 47, JP-A-3-59075, JP-A-3-103254, JP-A-3-221141, JP-A-4-11948, JP-A-4-92664, JP-A-4-138165. JP-A-4-266947, JP-A-5-9344, JP-A-5-68694, JP-A-5-161671, JP-A-5-179053, JP-A-5-269164, Those introduced in JP-A-7-165981 can be appropriately selected.

  Examples thereof include alkylpyridinium salts, benzalkonium chloride, chlorhexidine gluconate, pyridione zinc, silver-based inorganic powders, and the like. Representative examples of quaternary nitrogen-based antibacterial agents include methylbenzethonium chloride, benzalkonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide. Examples of the heterocyclic quaternary nitrogen-based antibacterial agents include dodecylpyridinium chloride, tetradecylpyridinium chloride, cetylpyridinium chloride (CPC), tetradecyl-4-ethylpyridinium chloride, and tetradecyl-4-methylpyridinium chloride.

  Other preferred antibacterial agents include bis-biguanides. These are described in detail, for example, in US Pat. Nos. 2,684,924, 2,990,425, 2,830,006 and 2,863,019. The most preferred bis-biguanide is 1,6-bis (4-chlorophenyl) diguanide hexane, known as chlorohexidine and its water-soluble salts. Particularly preferred are chlorohexidine hydrochloride, acetate and gluconate.

  Several other types of antibacterial agents are also useful. For example, carbanilides, substituted phenols, metal compounds, and rare earth salts of surfactants can be exemplified. The carbanilide includes 3,4,4′-trichlorocarbanilide (TCC, triclocarban) and 3- (trifluoromethyl-4,4′-dichlorocarbanilide (IRGASAN). Mention may be made of 5-chloro-2- (2,4-dichlorophenoxy) phenol (IRGASAN DP-300), which include graphite and tin salts such as zinc chloride, zinc sulfide and tin chloride. A rare earth salt of a surfactant is disclosed in European Patent Publication No. 10819. As this type of rare earth salt, a linear lanthanum salt of a C10-18 alkylbenzene sulfonate can be exemplified.

  Further, deodorizers, deodorizers and fragrances are used to prevent or alleviate the unpleasant odor of the absorbed liquid. Examples of the deodorant, deodorant, and fragrance are “new deodorant / deodorant and technology and prospect” (Toray Research Center (1994)), JP-A-59-105448, JP-A-60-158861, JP-A-61-118132, JP-A-1-153748, JP-A-1-221242, JP-A-1-265156, JP-A-2-41155, JP-A-2-253847, Those introduced in Japanese Laid-Open Patent Publication No. 3-103254, Japanese Laid-Open Patent Publication No. 5-269164, and Japanese Laid-Open Patent Publication No. 5-277143 can be appropriately selected. Specifically, examples of the deodorizer and deodorizer include iron complexes, tea extraction components, and activated carbon. Examples of fragrances include fragrances (citral, cinnamic aldehyde, heliotopine, camphor, bornyl acetate) wood vinegar, paradichlorobenzene, surfactants, higher alcohols, terpene compounds (limonene, pinene, camphor, borneol, eucalyptol, Eugenol).

  A foaming agent and a foaming aid can be used in combination to increase the porosity and the surface area in order to improve the water absorption performance of the water absorbent resin. As the foaming agent and foaming aid, for example, those introduced in “Rubber / Plastic Compounding Chemicals” (Rubber Digest, 1989, pages 259 to 267) can be appropriately selected. Examples include sodium bicarbonate, nitroso compounds, azo compounds, sulfonyl hydrazides and the like.

  These additives are appropriately added according to the purpose and action mechanism in each step of manufacturing the water-absorbent resin composite. For example, the foaming agent is suitably added in the production process of the water-absorbent resin, and is preferably added before the polymerization process or during the polymerization process. Human urine stabilizer, human blood stabilizer, antibacterial agent, deodorant, and fragrance can be added in the water absorbent resin composite manufacturing process, water absorbent resin composite composition manufacturing process, and absorbent article manufacturing process. It is. Of course, it can be applied to the fibers in advance. Moreover, you may add these additives in components other than the water absorbent resin complex which comprises an absorbent article.

As described above, the water absorbent resin composite composition of the present invention can be produced by mixing the water absorbent resin composite and fibers with a mixer. Thus, a water absorbent resin composite composition in which the water absorbent resin composite and the fibers are mixed in an arbitrary composition can be obtained. At the time of manufacture, water-absorbing resin particles that are not embedded or bonded with fibers may be mixed.
As the mixer, a solid mixing device capable of mixing powders, powders and fibers, or fibers can be used. Specific examples of the solid mixing device include a cylindrical mixer, a V mixer, a double cone mixer, a positive mixer, which are described in detail in “Chemical Engineering II” (Yoshinori Oyama, Zen Iwanami, 1963, p. 229). Examples thereof include a rotary mixer such as a cubic mixer, a screw mixer, a ribbon mixer, a rotary disk mixer, and a stationary mixer such as a fluidized mixer.

  In the polymerization step for producing the water-absorbent resin composite of the present invention, the water-absorbent resin composite composition can be obtained simultaneously by appropriately adjusting the fiber supply position and the like.

Furthermore, in order to improve the density of the water-absorbent resin composite composition and improve the adhesion to the fibers to the water-absorbent resin particles, the water-absorbent resin composite composition of the present invention may be subjected to a consolidation treatment. . The consolidation process can be performed by appropriately adjusting conditions such as pressure, temperature, and humidity using a press such as a flat plate press or a roll press. The pressure during the consolidation treatment may be within a range where the water absorbent resin particles are not broken. When the water-absorbent resin particles are broken, the broken particle pieces are detached from the fibers and leaked from the absorbent product, which is the final product, or the water-absorbing gel is released from the fibers and spills or moves when swollen. Performance will be reduced.
When heating at the time of a compaction process, it can heat to the temperature below the melting point of the fiber to be used. Heating to a temperature equal to or higher than the melting point is not preferable because the fibers bind to each other to form a network and the function of the composite may be impaired. When humidifying at the time of the consolidation process, it is usually possible to humidify using steam. By appropriately selecting the humidifying conditions, the density of the water absorbent resin composite composition can be improved, and the fixing property of the water absorbent resin particles to the fibers can be improved.

  The water-absorbing composite composition of the present invention can be easily opened because the constituent components themselves are independent of each other. For opening, the fiber opening method described in the description of the fiber and the description of the water absorbent resin composite can be used as appropriate, but it is possible to select an apparatus and conditions that do not damage the water absorbent resin due to mechanical impact. preferable.

[Absorbent articles]
(Constitution)
The absorbent article of the present invention includes one water-absorbing resin particle and two or more fibers, the water-absorbing resin particles are substantially spherical, and one or more of the two or more fibers are Part of the fibers are embedded in the resin particles and part of the fibers are exposed from the resin particles, and one or more of the two or more fibers are embedded in the resin particles. It is characterized by containing a water-absorbent resin composite in which a part of the fiber is bonded to the surface of the resin particle without being buried.

The structure of the absorbent article of the present invention can be appropriately determined according to the function and application required for the absorbent article. A typical absorbent article is a fluff pulp, tissue, nonwoven fabric, polyolefin sheet that is commonly used for absorbent articles, in which the water absorbent resin composite composition containing the water absorbent resin composite of the present invention forms a water absorption core. It is configured by appropriately combining with the above.
In particular, in so-called paper diapers and sanitary napkins, a diffusion layer of a hydrophobic fiber nonwoven fabric such as polyethylene fiber, polypropylene fiber or polyester fiber may be used in order to improve the diffusibility of body fluids during use. The water-absorbing composite may be freely mixed with fluff pulp or the like.
Moreover, you may mix powder water-absorbing resin etc. which are marketed. In the case of mixing, the water-absorbent resin dropout rate measured according to the water-absorbent resin dropout rate measuring method described later can be mixed and used within a range of preferably 5% or less.

  About the typical structural example of the diaper which is an absorbent article, the below-mentioned Example and FIG. 1 can be referred. The structure of FIG. 1 is obtained by laminating a tissue 22, a densified water-absorbent resin composite composition 24, a tissue 25, and a water-permeable polyester fiber nonwoven fabric 26 in this order on a water-impermeable polyethylene sheet 21. . After producing a laminated body, an absorbent article can be manufactured by applying pressure to bring each layer into close contact, and thermocompressing the four sides after releasing the pressure. The aqueous liquid to be absorbed is absorbed from the water permeable polyester fiber nonwoven fabric 26 side and absorbed by the water absorbent resin composite composition 24.

As shown in the structure of FIG. 1, by placing a fibrous base material such as tissue 25 or water-permeable polyester fiber nonwoven fabric 26 on the upper part of the water-absorbent resin composite composition 24, the aqueous liquid can be quickly discharged. Can be absorbed. Moreover, it is possible to make it difficult to release the absorbed aqueous liquid even when pressure is applied to the absorbent article.
Furthermore, by inserting a material imparting bulkiness such as fluff pulp into the absorbent article, the touch to the skin can be improved and the applicability to the body can be enhanced. Basis weight of the material giving bulkiness is preferably 80~250g / m ^2, and more preferably 100~220g / m ^2. The material imparting bulkiness is preferably provided between the water absorbent resin composite composition 24 and a substrate such as the water-impermeable polyethylene sheet 21, but the water absorbent resin composite composition 24 is sandwiched from above and below. It doesn't matter. However, when sandwiching from above and below, it is preferable that the lower basis weight is larger.

(Thinner)
When manufacturing a thin absorbent article, it is preferable to make the water absorbent resin composite composition of the present invention thin. Specifically, the bulk density of the water absorbent resin composite composition of the present invention is preferably in the range of 0.20 to 1.10 g / cm ³ , and is preferably in the range of 0.20 to 0.85 g / cm ³ . It is more preferable to make it inside. The density after thinning can be adjusted by conditions such as pressurization, heating, and humidification of the water absorbent resin composite composition. The thickness after thinning is preferably 0.2 to 20 mm, more preferably 0.2 to 10 mm, and still more preferably 0.2 to 5 mm.
As a method for reducing the thickness, for example, a pressure treatment method using a press machine can be mentioned. As a press machine, a flat plate press machine, a roll press machine, etc. can be used. The pressure is selected within a range where the water absorbent resin is not broken. If the water-absorbent resin is cracked, it will be detached from the fiber and leaked from the absorbent article, or the water-absorbing gel may be detached from the fiber and leaked or moved during swelling, thereby reducing the performance of the absorbent article.

In addition to the pressure treatment, the water-absorbent resin composite composition can be subjected to heat treatment and humidification treatment as necessary. The heating temperature in the case of heating can be selected below the melting point of the fiber to be used. When heated at a temperature higher than the melting point, the fibers are bound together to form a network, resulting in a result different from the object of the present invention. When humidifying, a method of spraying water on the water-absorbent resin composite composition, a method of supplying it as steam, or the like can be employed. The humidification amount can be appropriately selected depending on the content of the water-absorbent resin particles and the like, but is usually 500 g or less per 1 m ² , preferably 300 g or less per 1 m ² , more preferably 100 g or less per 1 m ² . If the amount of humidification is too much, the water-absorbent resin particles are softened and crushed, the fibers are bound together to form a network, and the result of the present invention is different from that of the present invention. Is not economical because it must be distilled off. When supplying with steam, the steam pressure should be lower than 10 MPa, and preferably lower than 1 MPa. Steam feed rate, the content of the water-absorbing resin particles, can be appropriately selected by moistening time, etc., normally less than 1 m ² per 300 kg / hr, preferably 1 m ² per 100 kg / hr or less, more preferably 1 m ² 50 kg / hr or less per unit. The treatment time is usually 1 hour or less, preferably 30 minutes or less, more preferably 20 minutes or less. If the amount of supplied steam is too large, the water-absorbing resin absorbs moisture and is softened and crushed, or fibers are bound together to form a network, resulting in a result different from the purpose of the present invention. This is not economical because a large amount of water must be distilled off later. Further, the absorbent article can be humidified by adding water by spraying or the like.

(Water absorption resin drop-off rate)
The absorbent article of the present invention is detached from the water-absorbent article after being shaken for 60 minutes at a frequency of 165 times / minute and a rotational speed of 290 times / minute using the shaker shown in FIG. 4 of JIS Z-8815. The weight of the water absorbent resin particles is preferably 5% by weight or less of the total weight of the water absorbent resin in the water absorbent article before shaking. About the detail of this test, description of the water-absorbent resin drop-off rate measurement mentioned later and JIS Z-8815 can be referred to.

  The water absorbent resin drop-off rate of the absorbent article of the present invention is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less. When the water-absorbing resin drop-off rate exceeds 5%, the water-absorbing resin particles to be detached in the absorbent article are unevenly distributed due to vibration or the like, and there is no place where the water-absorbing resin is present, and the body fluid liquid cannot be sufficiently absorbed, May cause leakage. If an absorbent article is manufactured using the water-absorbent resin composite composition described above, an absorbent article having a water-absorbent resin dropout rate of 5% or less can be obtained. In the case where water absorbent resin particles are additionally added to the absorbent article, it is preferably 5% or less of the total weight of the water absorbent resin. Moreover, when manufacturing an absorbent article with the method including a pressurization process, it is preferable to perform pressurization of the grade which a water absorbing resin particle does not break. Even if water-absorbing resin particles that can be freely moved by cracking are formed, it is preferable to adjust the water-absorbing resin particles to 5% or less of the total water-absorbing resin weight.

(Use)
Absorbent articles of the present invention include children's disposable diapers, adult disposable diapers, incontinence pads, sanitary materials such as sanitary products, absorbent sheets such as waste water, retaining sheets, cold insulation agents, waterproofing materials, sealing materials, and anti-condensation for construction It can be suitably used for industrial materials such as agents, soil water retention agents, water retention sheets for raising seedlings, freshness retention agents such as vegetables, and agricultural materials such as water retention agents.

  JP-A-63-267370, JP-A-63-10667, JP-A-63-295251, JP-A-270801, JP-A-63-294716, JP-A-64- No. 64602, JP-A-1-231940, JP-A-1-243927, JP-A-2-30522, JP-A-2-153373, JP-A-3-21385, JP-A-4-133728 The present invention can also be applied to the use of a sheet-like water-absorbing material proposed in Japanese Patent Laid-Open No. 11-156188.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples, comparative examples, and test examples. The materials, reagents, ratios, operations, and the like shown below can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

In the following description, “Composite A”, “Composite B”, and “Composite C” mean water-absorbent resin composites each having a structure defined below.
1) Composite A: A water absorbent resin composite containing one water absorbent resin particle and two or more fibers, wherein one or more of the two or more fibers are part of the resin. Embedded in the particles and partially exposed from the resin particles, and one or more of the two or more fibers are not embedded in the resin particles, A water-absorbent resin composite having a structure in which a part of fibers adheres to the surface of the resin particles.
2) Composite B: A water-absorbent resin composite comprising one or more water-absorbing resin particles and one or more fibers, wherein a part of the fibers of the one or more fibers are embedded in the resin particles. In addition, a water absorbent resin composite in which a part is exposed from the resin particles and none of the fibers are bonded to the surface of the resin particles.
3) Composite C: A water-absorbent resin composite including one or more water-absorbing resin particles and one or more fibers, wherein a part of the fibers of the one or more fibers are bonded to the surface of the resin particles. A water-absorbent resin composite in which all of the fibers are not embedded in the resin particles.

<Production Example 1> Production of water-absorbent resin composite To 100 parts by weight of acrylic acid, 3.3 parts by weight of water was added, and 133.3 parts by weight of a 25% by weight aqueous sodium hydroxide solution was cooled to 25 ° C or lower. By addition, a partially neutralized acrylic acid aqueous solution having a monomer concentration of 50% by weight and a neutralization degree of 60 mol% was prepared.
A solution obtained by adding 0.14 parts by weight of N, N′-methylenebisacrylamide as a crosslinking agent and 4.55 parts by weight of a 31% by weight aqueous hydrogen peroxide solution as an oxidizing agent to 100 parts by weight of the partially neutralized acrylic acid aqueous solution. A was prepared.
Separately, 0.14 parts by weight of N, N′-methylenebisacrylamide as a crosslinking agent and 0.57 parts by weight of L-ascorbic acid as a reducing agent were added to 100 parts by weight of the partially neutralized acrylic acid aqueous solution. Solution B was prepared.

The prepared solution A and solution B were mixed using the nozzle shown in FIG. The inner diameter of the nozzle in FIG. 2 is 0.125 mm, and five nozzles for each solution are arranged at 1 cm intervals. The crossing angle between the solution A and the solution B flowing out from the nozzle was adjusted to 30 degrees, and the distance between the nozzle tips was adjusted to 4 mm. Solution A and solution B were each heated to a temperature of 40 ° C. and supplied with a pump at a flow rate of 5.4 m / sec.
The solution A and the solution B merge when they exit the nozzles of the respective nozzle pairs, form a liquid column about 10 mm each, and then form liquid droplets in the gas phase (in air, at a temperature of 50 C) was dropped. On the other hand, in the middle of dropping a droplet 1.6 m below the nozzle tip (polymerization rate 40%), the opened pulp fiber (average length 2,500 μm, average thickness 2.2 dtex, water contact angle 0 °) Was supplied at a speed of 23 g / min as a multiphase flow with air (fiber: air = 1: 100) at a linear speed of 10 m / s. The droplets collided with pulp fibers in the gas phase to form a composite, and were deposited on a polyester net placed 3 m below the tip of the nozzle.

After collecting and drying the deposit, it is sieved to remove fibers that did not come into contact with the water-absorbent resin (fibers that are not embedded or bonded to the water-absorbent resin, hereinafter referred to as “free fibers”), A product composed of a water-absorbent resin and fibers was obtained.
When this product was observed with a microscope, it was a composition comprising Complex A (water-absorbent resin particles were approximately spherical; FIG. 3 shows a scanning micrograph) and Complex C (water-absorbent resin particles were approximately spherical). I was able to confirm. Water-absorbing resin particles in which fibers were not embedded or adhered were not observed.

<Manufacture examples 2-6> Manufacture of a water-absorbent resin composite In the procedure of manufacture example 1, all are the same methods except having changed the fiber material, average fiber length, and average fiber diameter as shown in Table 1, and water absorption. A product containing a functional resin composite was obtained.
In Production Example 5, polyethylene terephthalate (PET) fibers having a fiber diameter of 1.7 decix, a length of 0.9 mm, and a water contact angle of 80 ° were used. In Production Example 6, nylon having the same fiber diameter and length as that of nylon having a fiber diameter of 1.7 decix, a length of 0.9 mm and a water contact angle of 50 °, and a water contact angle of 0 ° A fiber mixture having a 1: 1 weight ratio with rayon was used.

<Manufacture example 7> Manufacture of a water absorbing resin composite Based on the Example of Unexamined-Japanese-Patent No. 63-63723, the water absorbing resin composite was prepared in the following procedures.
45.0 g of acrylic acid and 1.5 g of distilled water were weighed in a 200 ml beaker and neutralized with 60.0 g of 25% aqueous sodium hydroxide under cooling at 35 ° C. or lower to obtain a partially neutralized aqueous acrylic acid solution ( Monomer concentration 50 wt%, neutralization degree 60 mol%). Further, 41.9 mg of N, N′-methylenebisacrylamide and 0.31 g of L-ascorbic acid were dissolved in the partially neutralized acrylic acid aqueous solution to obtain a mixed monomer aqueous solution.

A hole was made in the top sheet of a 300 ml stainless steel beaker whose top surface was completely sealed with a polyester sheet, and the inside of the system was sufficiently purged with nitrogen through a rubber tube. After the mixed monomer aqueous solution was poured into the stainless steel beaker, the stainless steel beaker was immersed in a bath temperature of 50 ° C., and 0.84 g of 30% hydrogen peroxide water was added with stirring to perform polymerization. The maximum temperature was 110 ° C. after about 1 minute. Thereafter, it was kept in a 50 ° C. warm bath for 2 hours and then cooled to 20 ° C. to obtain a water-containing water-absorbent resin. 70 g of this water-containing water-absorbent resin (35 g of water-absorbent resin), 200 g of water and 10 g of the same pulp used in Production Example 1 were kneaded for about 2 hours using a screw rotary mixer and then 100 ° C. in a vacuum dryer. And dried for 8 hours, and further pulverized with a rotary blade type pulverizer. Furthermore, the free fiber was removed by sieving to obtain a product composed of a water-absorbent resin and fibers.
When this product was observed with a microscope, complex B could be confirmed, but complex A and complex C could not be confirmed.

<Manufacture example 8> Manufacture of a water-absorbent resin composite In the procedure of manufacture example 1, pulp fiber is supplied to a position (polymerization rate 15%) below 0.8 m from the nozzle tip with air at a supply rate of 23 g / min. A product containing a water-absorbent resin composite was obtained in the same manner except that the point on the polyester net was changed at a position 1.6 m below the tip of the nozzle (polymerization rate 40%).
When this product was observed with a microscope, it was confirmed to be composed of the complex B. Further, it was confirmed that the composite had a sheet shape in which the fibers were three-dimensionally networked with water-absorbing resin particles interposed therebetween. On the other hand, Complex A and Complex C could not be confirmed.

<Manufacture example 9> Manufacture of a water-absorbent resin composite In the procedure of manufacture example 1, all except having supplied the fiber from the fiber supply port installed in the lower part 0.8m from the front-end | tip of a nozzle, a water-absorbent composite is the same method. A product containing a water-absorbent resin composite was produced.
When this product was observed with a microscope, it was confirmed that the product was composed of the composite A (the water-absorbent resin particles were substantially spherical) and the composite B.

<Production Example 10> Production of water-absorbent resin composite 47.5 parts by weight of the composition obtained in Production Example 3 and 47.5 parts by weight of the composition comprising the two types of water-absorbent resin composites obtained in Production Example 9 Part and 5 parts by weight of the same fiber as used in Production Example 1 were uniformly mixed with a rotary blade mixer to obtain a product.
When this product was observed with a microscope, it was confirmed that the product was composed of the composite A (the water-absorbent resin particles were substantially spherical), the composite B, the composite C, and free fibers. As a result of microscopic observation, the weight ratio of the composite A in the total weight was 0.24.

<Manufacture example 11> Manufacture of a water absorbing resin composite Based on the Example of Unexamined-Japanese-Patent No. 11-93073, the water absorbing resin composite was prepared in the following procedures.
125 parts by weight of an 80% by weight acrylic acid aqueous solution and 133 parts by weight of a 30% by weight sodium hydroxide aqueous solution were mixed to obtain a partially neutralized acrylic acid aqueous solution having a neutralization degree of 72 mol% and a concentration of 47% by weight. In the partially neutralized acrylic acid aqueous solution, 0.04 part by weight of N, N′-methylenebisacrylamide as a crosslinking agent and 0.3 part by weight of 2,2′-azobis (2-amidinopropane) dihydrochloride as an initiator Was dissolved in 13 parts by weight of distilled water and degassed with nitrogen to obtain a monomer aqueous solution.

  A one-part spray nozzle was used instead of the nozzle used in Production Example 1, the liquid temperature was maintained at 25 ° C., and the liquid was supplied by a pump so that the flow rate was 40 ml / min. The monomer solution became droplets and dropped in the gas phase (in air, at a temperature of 25 ° C.) while the polymerization proceeded. On the other hand, in the process of dropping a droplet 0.8 m below the nozzle tip (polymerization rate <1%), the same fiber as used in Production Example 5 was mixed with air at a speed of 23 g / min (fiber: air = 1: 100) at a linear velocity of 10 m / sec. The droplet collided with the fiber in the gas phase to form a composite, and was deposited 3 m below the tip of the nozzle. The deposit was collected and placed in an oven at 80 ° C. to polymerize the adhering monomer aqueous solution for 30 minutes, and then treated with hot air at 140 ° C. to obtain a collected product containing a dried water-absorbent resin composite.

  Furthermore, the recovered material was sieved to try to remove free fibers that did not come into contact with the water-absorbent resin. The sheet was formed in a three-dimensional network, and there were virtually no free fibers. Thus, the product which consists of a water absorbing resin and a fiber was obtained.

  When this product was observed with a microscope, a structure in which some of the fibers were adhered to the surface of the resin particles was confirmed. However, a structure in which some of the fibers were embedded in the water-absorbing resin was not seen.

<Production of densified water-absorbing composite composition>
Using the weight ratio of each water-absorbing resin composite obtained in the above production example and the dry weight ratio of the binding fiber and the water-absorbing resin constituting each water-absorbing composite, the basis weight of the water-absorbing resin and the fiber (binding fiber + free fiber) The water absorbent resin composite and the free fiber were mixed so that the dry weight ratio of the fiber) to the water absorbent resin was a predetermined value.
For example, the dry weight ratios of the composite A, the composite B, and the composite C are a, b, and c (a + b + c = 1), respectively, and the dry weight ratio of the fibers that form each composite is α, β, and γ. From the resin composite x [g / m ² ] and the free fiber y [g / m ² ], the basis weight of the water absorbent resin is P [g / m ² ], and the dry weight ratio of the free fiber to the water absorbent resin is F [w / W] when producing a densified water-absorbent resin composite composition,
[a (1-α) + b (1-β) + c (1-γ)] x = P [g / m ² ]
When
y
――――――――――――――――――――――― ＝ F [w / w]
[a (1-α) + b (1-β) + c (1-γ)] x
X, y can be calculated if a, b, c, α, β, γ and P, F are given. However, here, P = 300 g / m ² (constant value).
This mixture is uniformly spread on a stainless steel plate so that it becomes 40 cm × 10 cm. Further, the stainless steel plate is overlaid on the stainless steel plate, a load of 0.6 MPa is applied from both sides, the mixture is left for 20 minutes, the pressure is released, and the high density A water-absorbent resin composite composition was obtained.

<Example and comparative example> Manufacture of an absorbent article Furthermore, the diaper which is 16 types of absorbent articles was manufactured in the following procedures using the densified water-absorbent resin composite composition (Examples 1-13). And Comparative Examples 1 to 3).
(1) On a water-impermeable polyethylene sheet (weight per unit area 18 g / m ² ) 21, tissue 22 (weight per unit area 14 g / m ² ), densified water absorbent resin composite composition 24 (water absorbent resin is 300 g / m). m ² and a size of 10 cm × 40 cm), tissue 25 (weight per unit area 14 g / m ² ), and water-permeable polyester fiber nonwoven fabric 26 (weight per unit area 23 g / m ² ) in this order, as shown in FIG. Then, it was sandwiched between stainless steel plates from both sides, applied with a pressure of 0.6 MPa, and allowed to stand for 20 minutes for adhesion.
(2) The pressure was released and the four sides of the water-absorbent article were thermocompression bonded.
(3) The outer end of the crimped part was cut out to produce a water-absorbent article of about 10 cm × about 40 cm.
In Example 10, however, distilled water was sprayed to 10 g / m ² before stacking the stainless steel plates, and then treated for 20 minutes under a pressure of 0.6 MPa. In Example 11, a stainless steel plate facing the water absorbent resin composite composition was overlaid with a stainless steel box having 1 mmφ holes at equal intervals, and then a pressure of 0.6 MPa was applied to the steam (STM) at 150 ° C. Was processed for 20 minutes while supplying 50 kg / hr / m ² into a stainless steel box.

<Test example> Evaluation of water-absorbent resin composite, densified water-absorbent resin composite composition and absorbent article About the water-absorbent resin composites produced in Examples 1 to 13 and Comparative Examples 1 to 3, morphology observation The average particle diameter of the water absorbent resin, the dry weight ratio of each composite, the dry weight ratio of the binding fibers and the water absorbent resin constituting each composite, the water retention capacity, and the water absorption speed were measured. In addition, the thickness, bulk density, bending resistance, restoration rate, and fiber-opening property were measured and evaluated for the densified water-absorbing resin composite composition prepared from each water-absorbing resin composite and free fibers. In addition, it considered that the weight composition ratio of each composite_body | complex and free fiber and the dry weight ratio of free fiber / water absorbent resin which comprise a densified water-absorbing-resin composite composition do not change with a densification process. Furthermore, an absorbent article was produced using the densified water-absorbing composite composition, and the absorption rate, water discharge amount, water-absorbing resin drop-off rate, and gel drop-off rate were measured. Each measurement result and evaluation result are shown in Table 1.
Moreover, the measuring method and evaluation method of each physical property in this invention are shown below.

1. Fiber 1-1) Contact angle of water (1) A solution having a concentration of 1 to 10% by weight was prepared using a solvent capable of dissolving or dispersing the fiber.
(2) The solution was thinly spread on a petri dish, and the solvent was gently evaporated with dry air at room temperature to dry sufficiently to obtain a thin film-like molded product.
(3) The contact angle of distilled water at 25 ° C. with respect to the air surface of the film-like molded product was determined. The contact angle was measured using an automatic contact angle meter CA-V type (manufactured by Kyowa Interface Science Co., Ltd.).

1-2) Spatial density The amount of residence in the reaction field of the fiber is calculated by assuming that the fiber moves from top to bottom on the air flow supplied together as a multiphase flow. The spatial density of the fibers in the reaction field was calculated by dividing by the volume of the reaction field.

2. Droplet 2-1) Droplet diameter The average particle diameter dp and the monomer concentration Cm of the water-absorbent resin particles constituting the water-absorbent resin composite, measured according to the method of 3-2) described later, were calculated according to the following formula.
Droplet diameter dd = dp / (Cm) ^1/3

2-2) Spatial density By assuming that the droplet falls in the reaction field with the downward discharge speed from the nozzle as the initial speed, the amount of residence of the droplet in the reaction field is calculated, and the amount of residence is further converted into the total reaction The spatial density of the droplets in the reaction field was calculated by dividing by the field volume.

2-3) Polymerization rate (polymerization rate at the position of contact with the fiber)
(1) A beaker containing about 150 g of methanol was placed so that the liquid level of methanol was located at the position where the fiber was introduced, and droplets of the reaction mixture that started polymerization were formed in the gas phase. About 1 g of a droplet in progress of polymerization was dropped into methanol in a beaker.
(2) The amount of monomer in methanol was measured by liquid chromatography.
(3) After the polymer in methanol was dried under reduced pressure at 130 ° C. for 3 hours, the weight was measured.
(4) The polymerization rate was calculated from the respective weights according to the following formula (Mp is the polymer weight,
Mm is monomer weight).
Mp
Polymerization rate (%) = ――――――――― × 100
Mm + Mp

3. Water-absorbing resin composite 3-1) Confirmation of form of water-absorbing resin composite By observing the water-absorbing resin composite with a scanning electron microscope at a magnification of 20 to 20,000 times, a part of the fiber is inside the resin. The structure in which a part of the fiber is exposed from the resin or the adhesion state of the fiber to the resin surface was confirmed.
Furthermore, by cutting the cross section continuously with a precision cutting device such as a microtome, and observing the cross section at a magnification of 20 to 20,000 times, a part of the fiber is embedded inside the resin, A structure in which part of the resin is exposed from the resin or the state of adhesion of fibers to the resin surface was confirmed.

3-2) Average particle diameter of water-absorbing resin particles 100 water-absorbing resin particles (the water-absorbing resin to be measured in this specification) constituting the composite by taking an optical micrograph of the water-absorbing resin composite All of the particles were substantially spherical) and their diameters were measured, and the average value based on the number was defined as the average particle size.

3-3) Dry weight ratio of each water-absorbing resin composite About 1 g of the water-absorbing resin composite was classified into a composite A, a composite B, and a composite C using an optical microscope. The weight of each composite was measured with a precision balance, and the dry weight ratio of each water absorbent composite was obtained.

3-4) Dry weight ratio of binding fiber and water-absorbent resin constituting each composite For each water-absorbent resin composite classified in 3-3) above, the water-absorbent resin in the composite is selectively decomposed. The fiber was isolated using a drug and determined by weighing the fiber weight.
Specifically, for example, regarding the water absorbent resin composite A,
(1) The weight of the water absorbent resin composite A obtained in 3-3) was defined as Wc. This water-absorbent resin composite A is charged in a 50 ml sealed glass container, and 0.03 g in 25 g of distilled water.
An aqueous solution in which L-ascorbic acid was dissolved was added to swell and kept at 40 ° C. for 24 hours.
(2) After that, the contents of the glass container were suction filtered with an aspirator having a final vacuum of 10 to 25 mmHg with a filter paper having a constant weight that was dried under reduced pressure at 80 ° C. for 3 hours, and the fibers on the filter paper were sufficiently washed with water. It was dried at 5 ° C. for 5 hours and precisely weighed, and the value was defined as Wf.
(3) The dry weight ratio between the binding fibers constituting the water absorbent resin composite A and the water absorbent resin was obtained by the following formula.
Wf
Dry weight ratio of binding fiber and water-absorbent resin = ―――――――――
Wc-Wf

3-5) Water retention capacity (1) A necessary amount of physiological saline (0.9% by weight sodium chloride aqueous solution) was prepared in advance.
(2) The ratio of the binding fiber and the water absorbent resin in the water absorbent resin composite is obtained by the same method as in the above 3-3) so that the weight of the water absorbent resin in the water absorbent resin composite is about 1 g. The water-absorbent resin composites were collected and their weight (W1) was measured. The weight (W2) of the fiber in the water absorbent resin composite was calculated from the ratio of the water absorbent resin to the fiber.
(3) This water-absorbent resin composite is 250 mesh nylon bag (20 cm × 10 cm)
And immersed in 500 ml of physiological saline at room temperature for 30 minutes.
(4) Next, the nylon bag was pulled up, suspended for 15 minutes and drained, and then dehydrated at 90 G for 90 seconds using a centrifuge.
(5) The weight W3 of the nylon bag containing the water absorbent resin composite after dehydration was measured.
(6) The same fiber as that used in the production is put in the same weight as the weight (W2) contained in the above composite, similarly in a 250 mesh nylon bag (20 cm × 10 cm), and room temperature physiological saline It was immersed in 500 ml for 30 minutes.
(7) Next, the nylon bag was pulled up, suspended for 15 minutes and drained, and then dehydrated at 90 G for 90 seconds using a centrifuge. Weight of nylon bag containing dehydrated fiber W4
Was measured.
(8) The water retention capacity S of physiological saline was calculated according to the following formula. Here, the units of W1 to W4 are all g.
W3-W4
Water retention capacity S = ――――――――――
W1-W2

3-6) Water absorption rate W1 to W4 were determined by the same method as 3-5) except that the immersion time (30 minutes) in physiological saline in the measurement method of 3-5) was changed to 5 minutes. In accordance with the same calculation formula as 3-5), the water absorption rate (= water retention capacity for 5 minutes) of the water absorbent resin composite composition was calculated.

4). Densified water-absorbing resin composite composition 4-1) Thickness The high-density water-absorbing resin composite composition was cut into 5 cm × 5 cm, and in accordance with JIS 1-1096, the densified water-absorbing resin composite composition. The thickness of the composition was measured (FIG. 4).
(1) A rheometer (FUDOH product, model number: NRM-2003J) with a diameter of 30 m
m adapter 1 is attached and the sample stage 2 is raised at a speed of 2 cm / min,
It was set to stop when a pressure of 0.2 psi was applied.
(2) Set the sample 3 on the measurement table and raise the sample table 2 to a distance of 4 from the upper surface of the adapter 1 to the lower surface of the sample table 2 at a position where the pressure is 0.2 psi and stopped. And measured.
(3) Five samples were measured and the average value was obtained.
(4) A blank measurement was performed at the same time without placing the sample on the sample stage 2.
(5) The thickness was determined from the following formula.
Thickness (mm) = Sample measurement value (mm)-Blank measurement value (mm)

4-2) Bulk density The densified water-absorbent resin composite composition was cut into 5 cm x 5 cm, its weight was measured, and the bulk density was determined from the following formula. Five samples were measured and the average value was obtained.
Sample weight (g)
Bulk density (g / cm ³ ) = ――――――――――――――――――――――
Sample thickness (cm) x sample area (cm ² )

4-3) Rigid softness The densified water-absorbent resin composite composition is cut into 2 cm × 25 cm, stored at a temperature of 25 ° C. and a humidity of 50% for a whole day and night, and then formed into a relatively soft woven fabric of JIS L-1096 shown in FIG. The stiffness was measured using the heart loop method used.
(1) A sample piece 52 was attached in a heart loop shape to a horizontal bar grip 51 shown in FIG. 5 so that the effective length of the sample piece was 20 cm.
(2) After 1 minute, the distance L (cm) between the top of the horizontal bar and the lowest point of the loop was measured. Here, L was defined as bending resistance. Five samples were measured and the average value was obtained.
Note that the sample of Comparative Example 2 was not flexible and did not form a heart loop, and could not be measured because it was broken in the middle (impossible to measure).

4-4) Restoration rate The densified water-absorbent resin composite composition was cut into 5 cm x 5 cm and compressed at a pressure of 10 MPa over 10 minutes, and 4-2) immediately after compression and at a temperature of 25 ° C based on the thickness measurement method. The thickness after storage for 30 days under the condition of humidity 50% was measured and calculated by the following formula. Five samples were measured and the average value was obtained.
Thickness after 30 days compression-Thickness immediately after compression (mm)
Restoration rate (%) = ――――――――――――――――――――― × 100
Thickness immediately after compression (mm)

4-5) Opening property (1) About 5 g of the water-absorbent resin composite composition was sandwiched between a pair of hand cards (22 cm × 12.5 cm) manufactured by Ashford, and manually lashed five times.
(2) Based on the ease of eyelashes and the state of breakage of the water-absorbent resin particles after eyelashes, the evaluation was made in three stages as follows.
◯: Easily lashed and the water-absorbent resin particles after lashing are hardly damaged.
Δ: The eyelashes have a feeling of resistance.
×: Resistance is strong enough to prevent eyelashes, or strong resistance to eyelashes,
When the eyelashes are broken, the water-absorbent resin particles after the eyelashes are significantly damaged.

5. Absorbent article 5-1) Absorption rate and water discharge amount With respect to the absorbent article, the absorption rate of artificial urine and the amount of artificial urine released by pressurization were measured by the following methods. An absorbent article 31 is placed on a flat surface, a cylinder 32 having an open inner diameter of 40 mm is attached at the center, and seven through-holes 33 having a diameter of 5 mm are formed in a portion surrounded by the cylinder 32. Acrylic plates 34 (100 × 100 × 10 mm, total weight 150 g) provided so as to be substantially equally spaced were placed as shown in FIG. Further, a metal disc (500 g) having a diameter of 100 mm and a hole having a diameter of 45 mm was inserted into the cylinder 32 and placed thereon. 25 ml of artificial urine was placed in the cylinder 32, and the time until it was absorbed was measured with a stopwatch, and this was taken as the absorption rate (seconds). After 10 minutes, the disc and the acrylic plate 34 with the cylinder 32 are removed, and 20 sheets of filter paper (Toyo Roshi Kaisha, ADVANTEC No. 424, 100 × 100 mm) are stacked on the absorbent article 31 on the acrylic plate 34. A load of 4 kg having a bottom area (10 cm × 10 cm) was placed on the filter paper. After 5 minutes, the load was removed, the weight of the filter paper was measured, and the amount of artificial urine absorbed by the filter paper was measured to obtain the water discharge amount (g). The above measurement was repeated three times, and the average value was taken as the absorption rate and the amount of water discharged.

5-2) Dropping rate of water-absorbing resin (1) A water-absorbing article was cut into a size of 10 cm × 10 cm (all sides were open), and the weight was measured. The total amount of water absorbent resin was determined from the weight ratio of the water absorbent resin in the water absorbent resin composite. Standard mesh sieve specified in JISZ8801 (the inner frame has an inner diameter of 1
The water-absorbent article cut out to 50 mm, depth 45 mm, 20 mesh) was fixed to the center with tape.
(2) A model SS-S-228 type low tap type shaker manufactured by Tokyo Shinohara Seisakusho Co., Ltd. was prepared.
(3) The number of impulses was set to 165 times / minute and the rotation number was set to 290 times / minute. The weight of the water-absorbent resin particles released from the water-absorbent article after 60 minutes of shaking was measured, and the drop-off rate was calculated from the following formula.
Dropped water-absorbing resin amount (g)
Water-absorbing resin dropout rate (%) = ――――――――――――――― × 100
Total water-absorbing resin before shaking (g)

5-3) Gel drop-off rate When the force acting so as to rub the water-absorbent article was repeatedly applied, the amount of the water-absorbent gel drop-off of the water-absorbent article was measured by the following procedure.
(1) A water-absorbing article 31 is placed on a flat surface, and a cylinder 32 having an inner diameter of 40 mm opened at the center is attached to a portion surrounded by the cylinder 32. Acrylic plate 34 provided with holes 33 at substantially equal intervals.
(100 × 100 × 10 mm, total weight 150 g) was placed as shown in FIG.
(2) 150 ml of artificial urine (composition later) was placed in a cylinder and absorbed by a water-absorbent article.
(3) After complete water absorption, the product was allowed to stand at room temperature for 30 minutes, and as shown in FIG. The weight of the cut part was measured.
(4) After the measurement, it was placed on the center of a 20 cm × 20 cm acrylic plate. A load (3 Kg) having a bottom area (10 cm × 10 cm) of the same size as the cut sample was placed so as not to protrude into the shape.
(5) Set the sample so that the cut end of the sample is perpendicular to the moving direction of the shaking machine (product of Inoue Seieido, Model No. MS-1), and the amplitude is 50 mm and the frequency is 80 times / minute. And shaken for 30 minutes.
(6) The load after shaking was removed, the weight of the water-absorbing gel dropped from the sample was measured, and the gel drop-off rate was calculated using the following formula.
Extruded gel amount (g)
Gel drop-off rate (%) = ―――――――――――――――― × 100
Total gel amount before extrusion (g)

6). Others Artificial urine having the following composition was used for the measurement of 5-1) absorption rate and water discharge amount, and 5-3) measurement of gel shedding rate.
1.94% by weight of urea
Sodium chloride 0.80% by weight
Calcium chloride 0.06% by weight
Magnesium sulfate 0.11% by weight
Distilled water 97.09% by weight

  In the absorbent article of the present invention, the water-absorbent resin particles are uniformly fixed to the fibers, and even if the water-absorbent resin particles absorb water and become a gel state, they are uniformly fixed to the fibers. The absorbent article of the present invention exhibiting such excellent performance has a very high utility value and is useful.

It is a cross-sectional view which shows the structure of an absorbent article. It is this schematic for demonstrating the nozzle used in order to produce a water absorbing resin composite. 3 is a scanning electron micrograph of the water absorbent resin composite obtained in Production Example 1. FIG. It is a cross-sectional view for demonstrating a thickness measuring tool. It is the schematic for demonstrating the measuring tool by a heart loop method. It is a cross-sectional view for demonstrating the liquid absorber to an absorbent article. It is the schematic which shows a low tap type shaker. It is a figure which shows the cutting line of the sample in a gel drop-off rate measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adapter 2 Sample stand 3 Sample 4 Distance 21 Water-impermeable polyethylene sheet 22 Tissue 24 Water-absorbent composite composition 25 Tissue 26 Water-permeable polyester fiber nonwoven fabric 31 Absorbent article 32 Cylinder 33 Through-hole 34 Acrylic plate 37 Standard mesh sieve 38 Tape 41 Center 42 Cutting line 45 Load 46 Cut sample 47 Acrylic plate 51 Grasp 52 Sample piece

Claims (22)

An absorbent article comprising water-absorbent resin particles and fibers, wherein the gel drop-off rate represented by the following formula (1) is 10% or less.
A
Gel drop-off rate (%) = ――― X 100 (1)
B
(In the above formula, A is the weight of the falling water-absorbing gel after a load of 3 kg is placed on the water-absorbing absorbent article and shaken for 30 minutes at an amplitude of 50 cm and a frequency of 80 times / minute, and B is shaken. It is the weight of the previous water-absorbing gel.)   An absorbent article comprising a water absorbent resin composite comprising one water absorbent resin particle and two or more fibers, wherein the water absorbent resin particles are substantially spherical and of the two or more fibers. At least one of the fibers is embedded in the resin particles and part of the fibers are exposed from the resin particles, and at least one of the two or more fibers is formed of the resin. The absorbent article according to claim 1, wherein a part of the fiber is adhered to the surface of the resin particle without being embedded in the particle.   The absorbent article according to claim 1 or 2, wherein a dry weight ratio between the fibers and the water-absorbent resin particles is 1: 1 to 1: 1,000,000.   The absorbent article according to any one of claims 1 to 3, wherein the water absorbent resin particles have an average particle diameter of 50 to 1,000 µm.   The absorbent article according to any one of claims 1 to 4, wherein an average fiber length of the fibers is 50 to 10,000 µm.   The absorbent article according to any one of claims 1 to 5, wherein an average fiber diameter of the fibers is 0.1 to 500 dtex.   The absorbent article according to any one of claims 1 to 6, wherein one or more of the two or more fibers are fibers having a contact angle with water of 60 ° or less.   The absorbent article according to claim 7, wherein the fiber is cellulose.   The absorbent article according to claim 1, wherein the water absorbent resin is an unsaturated carboxylic acid polymer crosslinked product.   The absorbent article according to any one of claims 1 to 9, comprising a water absorbent resin composite composition mainly comprising a water absorbent resin and fibers, and comprising the water absorbent resin composite.   The absorbent article according to claim 10, wherein the water-absorbent resin composite composition contains the water-absorbent resin composite in a weight fraction of 0.1 or more.   A water-absorbing resin composite comprising one or more water-absorbing resin particles and one or more fibers, wherein the water-absorbing resin particles are substantially spherical, and one or more of the fibers of the one or more fibers are the resin. A water-absorbing resin composite that is embedded in particles and part of which is exposed from the resin particles, and in which all the fibers are not bonded to the surface of the resin particles. The absorbent article according to claim 10 or 11, which is contained in the composition.   A water-absorbing resin composite comprising one or more water-absorbing resin particles and one or more fibers, wherein the water-absorbing resin particles are substantially spherical, and one or more of the fibers of the one or more fibers are the resin. The water-absorbent resin composite composition comprising a water-absorbent resin composite that is bonded to the surface of the particles and in which none of the fibers are embedded in the resin particles. The absorbent article in any one.   The absorbent article according to any one of claims 10 to 13, wherein the water-absorbent resin composite composition includes one or more fibers that are not embedded or adhered to the water-absorbent resin.   The dry weight ratio of the fiber and the water absorbent resin that is not embedded or adhered to the water absorbent resin in the water absorbent resin composite composition is 90:10 to 5:95. Absorbent article.   The absorbent article according to claim 14 or 15, wherein the length of the fiber that is not embedded or adhered to the water-absorbent resin is 50 to 50,000 µm. The absorbent article according to any one of claims 10 to 16, wherein the water-absorbent resin composite composition has a bulk density of 0.20 to 1.10 g / cm ³ .   The absorbent article according to any one of claims 10 to 17, wherein a thickness of the water absorbent resin composite composition is 0.2 to 5.0 mm.   The absorbent article according to any one of claims 10 to 18, wherein the water absorbent resin composite composition is openable.   Sanitary material using the absorbent article according to any one of claims 1 to 19.   The industrial material using the absorbent article in any one of Claims 1-19.   Agricultural material using the absorbent article according to any one of claims 1 to 19.