JP2003235889A - Absorptive article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorptive article having an excellent resistance to leaking. <P>SOLUTION: The absorptive article including a water absorptive resin (a) of 0.01 to 3 in the rate of gel permeation (ml/min) and a water absorptive resin (b) of 5 to 200 in the rate of gel permeation (ml/min) is used. The rate of gel permeation is determined from the following equation by feeding a measuring sample into a filtration cylindrical tube having a wire net and capillary with a cock at the bottom end of an aperture of a perpendicularly erected cylinder, pouring physiological saline therein, and allowing the sample to stand still for 30 minutes after the beginning of the pouring, then inserting a load with the wire net into the filtration cylinder in such a manner that the wire net and the measuring sample come into contact with each other, placing a weight on the load with the wire net after one minute, and further allowing the sample to stand still for one minute, then opening the cock and measuring the time (T1) (second) before the liquid level of the physiological saline reaches a graduation line of 20 ml from a graduation line of 40 ml: (The rate of gel permeation)=20×60/(T1-T0). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an absorbent article.
More specifically, it relates to an absorbent article suitable as a sanitary article (disposable disposable diaper, sanitary napkin, incontinence pad, breast pad, surgical underpad, puerperium mat, dressing material for wound protection, pet sheet, etc.).

[0002]

2. Description of the Related Art Absorbent articles comprising a top sheet, a back sheet and two absorbent layers for the purpose of improving the absorption rate of urine or blood, improving the dry feeling after absorption and reducing leakage. Thus, the absorbent layer near the top sheet has a water-absorbing polymer with a liquid passage time of 20 seconds or less, and the absorbent layer near the back sheet has a water absorption rate of 5 g / 30 seconds / by the DW method (Demand Wettability method). There is known an absorbent article or the like which has a water-absorbing polymer of 0.3 g or more and prevents both polymers from being mixed (JP-A-10-118117).

[0003]

However, in the above-described absorbent article, the effect of preventing leakage from the water-absorbent article when actually used is not sufficient, and further improvement is strongly desired. Especially when used as a hygiene product, there is a problem that when urinating, urine leaks from the side of the diaper and stains the clothes. In addition, this problem tends to become more prominent as the absorbent article becomes thinner. That is, the object of the present invention is to provide a water-absorbent article having excellent leakage resistance.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that the above problems can be solved by using a plurality of specific water-absorbent resins. Arrived That is, the absorbent article of the present invention is characterized in that the gel flow rate (ml / min) is 0.0.
The gist is that it includes a water-absorbent resin (1) having a ratio of 1 or more and 3 or less and a water-absorbing resin (a) having a gel flow rate (ml / min) of 5 or more and 200 or less.

The gel flow rate is such that the wire mesh (opening 1) at the lower end of the opening of a vertically standing cylinder (inner diameter 25.4 mm).
50 μm) and a thin tube (inner diameter 4 mm) with a cock (inner diameter 2 mm)
m, length 8 cm), in a state where the cock is closed, 0.200 g of a measurement sample adjusted to a particle size of 850 to 150 μm is put into a filtration cylindrical tube having 50 ml of physiological saline.
After pouring, let it stand for 30 minutes after starting pouring, and then load with a wire mesh (opening 150 μm, diameter 25 mm) (21.2
g) is inserted into the filtration cylinder so that the wire mesh and the measurement sample are in contact with each other, and after 1 minute, the weight (77.0 g) is placed on the load with the wire mesh and left still for 1 minute, and then the cock is opened,
The time (T1) (seconds) until the liquid surface of the physiological saline reaches the scale line of 40 ml to the scale line of 20 ml is measured and calculated from the following formula {(T0) is the time when there is no measurement sample. }.

[0006]

[Equation 3]

[0007]

The gel permeation rate (ml / min) of the water absorbent resin (a) of the present invention is preferably 0.01 or more, more preferably 0.05 or more, and particularly preferably 0.10 or more. , More preferably 0.15 or more, most preferably 0.2 or more. Also, 3 or less is preferable,
More preferably 2.5 or less, particularly preferably 2 or less,
It is more preferably 1.5 or less, and most preferably 1 or less. Within this range, the absorbent article tends to have further improved resistance to leakage.

The method for measuring the gel flow rate (mi / min) will be described in more detail below. The measurement is
The measurement is performed in a measurement room at a room temperature of 25 ± 5 ° C. and a humidity of 50 ± 5% RH. First, a cylinder (inside diameter 25.
4 mm, for example, manufactured by Geberal, trade name CF-3
At the lower end of the opening (0K), a thin tube (inner diameter 4m) with a wire mesh (opening 150μm) and an openable and closable cock (inner diameter 2mm)
m, length 8 cm) in a filtration cylindrical tube with the cock closed and from the upper end of the cylindrical tube to JIS standard sieve (JIS Z8801-2000) 850-150.
0.200 g of a measurement sample adjusted to a particle size of μm is put on a wire net (opening 150 μm) so as to have a uniform thickness.

Next, from the upper part of the cylinder, 50 ml of physiological saline (0.9 wt% sodium chloride aqueous solution) at 25 ± 5 ° C. was poured within 10 seconds from the start of pouring, and after standing for 30 minutes, Wire mesh (opening 150 μm, diameter 2
5 mm) attached load (21.2 g) was inserted into the filtration cylinder so that the wire mesh and the measurement sample were in contact with each other, and after 1 minute, the weight (77.0 g) was placed on the wire attached load and left still for 1 minute. After that, open the cock and let the liquid level of the saline solution be 40
The time (T1) (seconds) from the graduation line of ml to the graduation line of 20 ml is measured, and the gel flow rate (ml / min) is calculated from the above formula. Note that (T0) is a blank (time) measured in the same manner except that 0.200 g of the measurement sample is not used. Also, the wire mesh opening is JI
It is based on S Z8801-2000 (hereinafter the same).

As a measuring device for the gel flow rate, for example, the measuring device shown in FIGS. 1 and 2 can be used. 1 and 2 are cross-sectional views of a state in which the measuring device is disassembled into parts. This measuring device is a filtration cylindrical tube {cylinder (1), wire mesh (2), packing (3), joint for fixing thin tube (4).
And a thin tube (5) with a cock}, and a load {load (6) with a wire mesh, lid (7) and weight (8)}. In addition,
As described above, a device other than a device that can be disassembled into parts can be used. It is also possible to use a device comprising a filter cylindrical tube and a load with a wire net (6), a lid (7) and a weight (8) integrated with each other.

The cylinder (1) is fixed so that the cylinder axis of the cylinder (1) is vertical. The inner diameter of the cylinder (1) is 2
It is 5.4 mm, and for example, CF-30K (external diameter 29.0 mm, length 35 cm) manufactured by Geberal Co. can be used. The lower end of the cylinder (1) has a screw thread (male) that is joined to the joint (4) for fixing the thin tube. In addition, the cylinder (1) has 40 ml and 20 ml in advance.
(The scale line showing the interface of the physiological saline in the cylinder (1) when 40 ml of physiological saline of 25 ± 5 ° C. and 20 ml of physiological saline is put into the filtration cylinder).

The mesh of the wire net (2) is 150 μm. The wire netting (2) has a circular shape and closely adheres so as to close the lower end of the cylinder (1). The size of the wire mesh (2) is
It is larger than the inner diameter of the cylinder (1) and smaller than the outer diameter of the cylinder (1). Further, a packing (3) for preventing liquid leakage is provided on the outer peripheral end of the wire net (2). The inner diameter of the packing (3) is almost the same as the inner diameter of the cylinder (1), and the outer diameter is the same as or slightly smaller than the outer diameter of the cylinder (1), for example, a diameter of 28.5 m.
m.

The thin tube fixing joint (4) has a thread (female) for joining with the cylinder (1). By joining this screw thread (female) with the screw thread (male) of the cylinder (1), the cylinder (1), the wire mesh (2), the packing (3), the joint (4) for fixing the thin tube and the cock The thin tube (5) can be integrated, and the gel flow rate can be measured in this integrated state.

The small tube portion of the thin tube (5) with a cock has an inner diameter of 4 mm and a length of 8 cm. The cock is openable and closable, the inner diameter of the cock is 2 mm, and the length of the inner diameter portion of 2 mm is 8 mm. Further, at one end of (5), a circular plate having a diameter of 25.4 mm that can be brought into close contact with the packing (3) is arranged so as to be perpendicular to the cylindrical axis of (5). There is a hole with a diameter of 4 mm in the center of the circular plate,
This hole is connected to the inside of the thin tube.

A load (6) with a wire mesh has a diameter of 25 mm at one end of a rod (for example, a cylindrical rod having a length of 44 cm and a diameter of 2 mm).
Wire mesh (opening 150 μm) is arranged so as to be orthogonal to the rod. In addition, a stopper for holding a weight is provided in a portion that is longer than the length of the cylinder (1) from one end of the rod (for example, when the cylinder (1) has a length of 35 cm, a portion closer to the center by about 4 cm from the other end). The stopper is for preventing the weight (8) from passing over the stopper and coming into contact with the cylinder (1) or moving into the inside of (1). The weight (6) with a wire mesh is 21.2 g. In addition, between the wire mesh and the stopper, there is a lid (7) that can move freely while contacting the rod.

The lid (7) can be arranged on the upper end of the cylinder (1) (the other end other than the threaded lower end) to form a lid. The lid makes it easier to hold the rod vertically and stabilizes the center of gravity of the weight, making it easier to apply a uniform load to the measurement sample. As a result, the measured value is stabilized. The weight (8) weighs 7
It is 7.0 g. In addition, the weight (8) has a hole (for example, an inner diameter of 2 mm) into which a rod can be inserted at the center thereof.

As a raw material for producing the water absorbent resin (a),
(1) Japanese Patent Publication No. 53-46199 or Japanese Patent Publication No. 5
3-46200, (2) JP-A-55-13341
No. 3, Japanese Patent Publication No. 54-30710, No. 56-26909, or No. 11-580.
No. 8, JP-A-52-14689 or JP-A-52-27455, and (5) JP-A-58-
2312 or JP 61-36309, (6) US Pat. No. 4,389,513, (7) JP 4
6-43995 or (8) US Pat. No. 4,650,71.
The production raw materials (polymerizable monomer, polymerization initiator, internal crosslinking agent, surface crosslinking agent, etc.) described in No. 6 can be used.

In order to make the gel permeation rate of the water absorbent resin (a) within the above range, (a1) a method of using the internal cross-linking agent in the usage amount range described later, and (a2) the surface cross-linking agent will be described later. It is possible to apply a method of using within the usage amount range, a method of using (a3) an internal cross-linking agent and a surface cross-linking agent together within the usage range below, and the like. Among these methods, from the viewpoint of water absorption performance (water retention capacity, absorption capacity under pressure), (a1) and (a1)
The method 3) is preferred.

As the polymerizable monomer, among the compounds described in the above publications, from the viewpoint of price, etc., (meth) acrylic acid, alkali metal (meth) acrylate (lithium, sodium or potassium etc.) salt, starch, etc. , Acrylonitrile and (meth) acrylamide are preferred, more preferably (meth) acrylic acid, (meth) acrylic acid alkali metal salt and starch, particularly preferably (meth) acrylic acid and (meth) acrylic acid alkali metal salt, most preferably Is (meth) acrylic acid and sodium (meth) acrylate. Two or more of these polymerizable monomers may be used in combination.

As the polymerization initiator, among those described in the above publications, a water-soluble radical polymerization initiator is used from the viewpoint of the water absorption performance (water retention capacity, absorption capacity, absorption capacity under load) of the water absorbent resin (a). And more preferably peroxides (hydrogen peroxide, t-butyl peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, etc.) and azo initiators [2,2-azobis {2- [N-
(2-Carboxyethyl) amidino] propane}, 4,
4'-azobis (4-cyanovaleric acid) and 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] etc.], particularly preferably hydrogen peroxide, t-butylperoxide Oxide, sodium persulfate, 2,2-azobis {2- [N- (2-carboxyethyl) amidino] propane}, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide ].

Two or more of these polymerization initiators may be used in combination, and the peroxide may be a reducing substance (for example, sodium sulfite, ferrous sulfate, L-ascorbic acid, etc.).
Alternatively, a redox initiator can be used in combination with an amine (dimethylaniline or the like). Also,
The amount of the polymerizable initiator used is the same as the amount described in the above publication.

As the internal cross-linking agent, the above-mentioned publication (Japanese Patent Publication No.
Among the internal cross-linking agents described in JP-A 3-46199 or JP-A-11-5808, etc., from the viewpoint of water absorption performance (water retention capacity, absorption capacity, absorption capacity under pressure) of the water absorbent resin (a), A compound having two or more polymerizable unsaturated groups, a compound having two or more functional groups in the molecule, and a compound having a polymerizable unsaturated group and a functional group are preferable, and more preferably a polymerizable unsaturated group is 2 A compound having two or more functional groups and a compound having two or more functional groups in the molecule, particularly preferably a compound having two or more polymerizable unsaturated groups. Two or more of these internal cross-linking agents may be used in combination. Here, the polymerizable unsaturated group means a (meth) acryloyl group, an allyl group, a vinyl group, and a propenyl group. The functional group means a functional group capable of reacting with a functional group contained in the polymerizable monomer (for example, a carboxyl group, a hydroxyl group, an amino group, etc.), such as a glycidyl group, an isocyanate group, and N-hydroxy group. Examples thereof include a methyl group, an epoxy group and a hydroxyl group.

The compounds having two or more polymerizable unsaturated groups include N,
N'-methylenebis (meth) acrylamide, ethylene glycol di (meth) acrylate, polyethylene glycol (degree of polymerization 2-100) di (meth) acrylate,
Propylene glycol di (meth) acrylate, glycerin-di or tri- (meth) acrylate, trimethylolpropane tri (meth) acrylate, triallylamine, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane and pentaerythritol triallyl. Ether is preferable, more preferably N, N′-methylenebis (meth) acrylamide,
Ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetraallyloxyethane, pentaerythritol triallyl ether and triallylamine.

As the compound having two or more functional groups in the molecule, among the compounds described in the above publication, ethylene glycol diglycidyl ether, polyethylene glycol (polymerization degree = 2 to 50) diglycidyl ether, propylene glycol diether Glycidyl ether, polypropylene glycol (degree of polymerization = 2 to 50) diglycidyl ether, glycerin diglycidyl ether and polyglycerin (degree of polymerization = 2 to 50) diglycidyl ether are preferred, and ethylene glycol diglycidyl ether and polyethylene glycol ( Degree of polymerization = 2-5
0) diglycidyl ether, glycerin diglycidyl ether and polyglycerin (degree of polymerization = 2 to 50) diglycidyl ether. Of the compounds described in the above publications, allylated starch, allylated cellulose and methylolated (meth) acrylamide are preferable as the compound having a polymerizable unsaturated group and a functional group.

When an internal cross-linking agent is used in the production of the water absorbent resin (a), the amount of the internal cross-linking agent used (% by weight) is
From the viewpoint of gel flow rate, it is preferably 0.001 or more, more preferably 0.05 or more, and particularly preferably 0.1 or more, based on the total weight of the polymerizable monomer and the internal crosslinking agent. Further, it is preferably 1 or less, more preferably 0.5 or less, and particularly preferably 0.3 or less. The internal cross-linking agent can be added by the method described in the above publication (Japanese Patent Publication No. 53-46).
For example, the method described in Japanese Patent Application Laid-Open No. 199 or Japanese Patent Application Laid-Open No. 11-5808 can be applied.

As the surface cross-linking agent, the above-mentioned JP-A-53-
In addition to those described in JP-A-46200 and JP-A-11-5808, polyvalent glycidyl described in JP-A-59-189103, JP-A-58-180233 or JP-A-61-16903. Polyhydric alcohols, polyhydric amines, polyhydric aziridines and polyhydric isocyanates described in JP-A No. 61-211305, JP-A No. 61-252212, and the like. The polyvalent metals described in JP-A-51-136588 or JP-A-61-257235 can be used. Among these, polyvalent glycidyl, from the viewpoint of water absorption performance (water retention capacity, water absorption capacity under pressure) and economical efficiency,
A polyvalent amine and a silane coupling agent are preferable, a polyvalent glycidyl and a silane coupling agent are more preferable, and a polyvalent glycidyl is particularly preferable.

When a surface cross-linking agent is used in the production of the water absorbent resin (a), the amount (% by weight) of the surface cross-linking agent used is
From the viewpoints of water absorption performance (water holding capacity, water absorption capacity under pressure) and gel flow rate, based on the weight of the polymerizable monomer, 0.00
1 or more, more preferably 0.005 or more,
It is particularly preferably 0.01 or more. Further, it is preferably 2 or less, more preferably 1 or less, particularly preferably 0.5.
It is the following.

The surface cross-linking treatment is carried out at any stage before the drying of the polymer (P), during the drying of the (P), and after the drying of the (P) during the production process of the water absorbent resin (A). However, from the viewpoint of easy adjustment of the crosslinking conditions with respect to the target performance, the stage during or after the drying of (P) is preferable.

As a method for carrying out this surface cross-linking treatment, a conventionally known method (for example, JP-A-53-46200) can be applied, but the surface cross-linking agent can be more uniformly added to the surface of the water absorbent resin. Therefore, the method of mixing the mixed solution of the surface cross-linking agent, water and the organic solvent with the polymer (P) and reacting with heating is preferable. The amount (% by weight) of water used for the surface cross-linking treatment is preferably 10 or less, based on the weight of the polymerizable monomer, from the viewpoint of the permeability of the surface cross-linking agent into the inside of the polymer (P), It is more preferably 8 or less, and particularly preferably 7 or less. Further, it is preferably 1 or more, more preferably 1.5 or more, and particularly preferably 2 or more.

As the type of organic solvent used in the surface cross-linking treatment, conventionally known hydrophilic solvents can be used, and the degree of penetration of the surface cross-linking agent into the polymer (P),
Although it can be appropriately selected in consideration of the reactivity of the surface cross-linking agent, for example, hydrophilic organic solvents such as methanol, ethanol, ethylene glycol, propylene glycol and diethylene glycol which are soluble in water are preferable. Such solvents may be used alone or in combination of two or more. The amount of the organic solvent used (% by weight) can be variously changed depending on the type of the organic solvent, but is preferably 0.2 or more, more preferably 0.5 or more, based on the weight of the polymerizable monomer. It is particularly preferably 1 or more. Further, it is preferably 20 or less, more preferably 15
It is preferably 10 or less, particularly preferably 10 or less.

The use ratio of the organic solvent to water can be arbitrarily changed, but the use amount (% by weight) of the organic solvent is preferably 80 or less, more preferably 75 or less, based on the weight of water. And particularly preferably 70 or less. Further, it is preferably 20 or more, more preferably 25.
The above is more preferable and the above is particularly preferable. The temperature of the surface cross-linking treatment is preferably 200 ° C. or lower, more preferably 1
The temperature is 80 ° C. or lower, particularly preferably 160 ° C. or lower, preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and particularly preferably 100 ° C. or higher.

The reaction time of the surface cross-linking treatment can be changed depending on the reaction temperature, but is preferably 60 minutes or less,
It is more preferably 50 minutes or less, particularly preferably 40 minutes or less, preferably 3 minutes or more, more preferably 5 minutes or more, particularly preferably 10 minutes or more. The water-absorbent resin obtained by surface-crosslinking with a surface-crosslinking agent may be subjected to additional surface-crosslinking with a surface-crosslinking agent of the same type or a surface-crosslinking agent of a different type. The amount of additional surface cross-linking agent used,
The treatment method, treatment temperature, treatment time, etc. are the same as in the above case.

As the method for producing the water absorbent resin (a), the polymerization methods described in the above (1) to (8) can be used. Among these, (1) to (3) in that they can be manufactured at low cost.
The polymerization methods described are preferable, and (2) and (3) are more preferable.

The water retention capacity (g / g) of the water absorbent resin (a) is
It is preferably 35 or more, more preferably 37 or more, particularly preferably 38 or more, more preferably 40 or more, and most preferably 42 or more. Further, it is preferably 80 or less, more preferably 75 or less, particularly preferably 70 or less, more preferably 65 or less, and most preferably 60.
It is the following. Within this range, the resistance to leakage under load tends to be better when applied to an absorbent article.
In order to keep the water retention capacity of the water absorbent resin (a) within the above range, the internal cross-linking agent is 0.05 wt% or more and 0.5 wt% or less based on the total weight of the polymerizable monomer and the internal cross-linking agent. The method of using and / or the method of using the surface crosslinking agent in an amount of 0.005% by weight or more and 1% by weight or less based on the weight of the polymerizable monomer can be applied.

The water retention capacity (g / g) is measured as follows. That is, the opening is 63 μm (JIS Z
8801-2000) made of nylon mesh into a tea bag (20 cm long, 10 cm wide rectangular bag)
85 with S standard sieve (JIS Z8801-2000)
1.000 g of measurement sample adjusted to a particle size of 0 to 150 μm
Is weighed in and immersed in 1 liter of physiological saline (0.9 wt% sodium chloride aqueous solution) whose temperature is adjusted to 25 ± 5 ° C. for 60 minutes. Then, it is centrifuged and dehydrated at 150 G, and the weight (X) of the entire nylon mesh bag is measured.
The same operation is performed for only the tea bag, the weight (X ') is measured as a blank, and the water retention amount is calculated from the following formula. In addition, weigh 4 digits after the decimal point and measure
Round off the digits.

[0036]

[Equation 4]

Water absorption capacity (g / g) of the water absorbent resin (a)
Is preferably 40 or more, more preferably 45 or more,
It is particularly preferably 50 or more, and most preferably 55 or more. Further, it is preferably 85 or less, more preferably 80 or less, particularly preferably 75 or less, and most preferably 70 or less. Within this range, when applied to an absorbent article, the leak resistance under normal pressure tends to be further improved. In order to set the absorption capacity of the water absorbent resin (a) within the above range,
A method of using an internal cross-linking agent in an amount of 0.05 wt% or more and 0.5 wt% or less based on the total weight of the polymerizable monomer and the internal cross-linking agent, and / or a surface cross-linking agent in the weight of the polymerizable monomer. Based on this, a method of using 0.005% by weight or more and 1% by weight or less can be applied.

The absorption capacity is measured as follows. That is, the opening 63 μm (JIS Z8801
-2000) nylon bag made of nylon net (length 20 cm, width 10 cm rectangular bag), JIS standard sieve (JIS Z8801-2000) 850-15
1.000 g of a measurement sample adjusted to a particle size of 0 μm is weighed and put, and immersed in 1 liter of physiological saline (0.9 wt% sodium chloride aqueous solution) whose temperature is adjusted to 25 ± 5 ° C. for 30 minutes. Then, the tea bag is taken out of the physiological saline, hung at room temperature for 15 minutes to drain water, and then the weight (Y) is measured. The same operation is performed for only the tea bag, the weight (Y ′) is measured as a blank, and the water absorption capacity is calculated from the following equation. In addition, weigh up to four decimal places and round off the fourth digit.

[0039]

[Equation 5]

Water absorption capacity under pressure of the water absorbent resin (a) (g /
g) is preferably 8 or more, more preferably 10 or more, particularly preferably 12 or more, and most preferably 15 or more. It is preferably 40 or less, more preferably 3
5 or less, particularly preferably 30 or less, most preferably 25
It is the following. Within this range, the resistance to leakage under load tends to be better when applied to an absorbent article.
In order to set the water absorption capacity under pressure of the water absorbent resin (a) within the above range, the internal crosslinking agent is added in an amount of 0.05% by weight or more and 0.5% by weight or more based on the total weight of the polymerizable monomer and the internal crosslinking agent. weight%
The method used below and / or the method using 0.005% by weight or more and 1% by weight or less of the surface crosslinking agent based on the weight of the polymerizable monomer can be applied.

The water absorption capacity under pressure is measured as follows. That is, the opening is 63 μm (JIS Z8
(801-2000) in a cylindrical tube (inner diameter 30 mm, height 60 mm) with a nylon mesh attached to the bottom, using a standard sieve (JIS Z8801-2000) 25
Measurement sample obtained by sieving particles of 0 μm to 500 μm.
160 g is weighed and put on a nylon net so as to have a substantially uniform thickness, and a weight having an outer diameter of 29.5 mm × 22 mm (inner wall of the cylindrical tube is applied so that a load of 42 g / cm ² is applied on the measurement sample. There is a gap of 0.5 mm between the weight and the weight so that the load of the weight is directly applied to the measurement sample, and the total weight (W1) is measured. Then room temperature 25 ± 5
Saline (0.9 wt% sodium chloride aqueous solution) 60m in a room controlled at 50 ℃ and humidity of 50 ± 5RH%
Petri dish containing l {diameter: 12 cm, regular triangular prismatic acrylic rod in the center (2 mm on one side of the triangle x 5 c in length)
m) Two tubes arranged in parallel at an interval of 30 mm}, and the cylindrical tube containing the measurement sample and the weight is placed on the triangular prism with the nylon net side facing down and left. After 60 minutes, the total weight (W2) of the cylindrical can containing the measurement sample and the weight is weighed, and the water absorption capacity under pressure for physiological saline is calculated from the following formula. In addition, weigh up to four decimal places and round off the fourth digit.

[0042]

[Equation 6]

Gel permeation rate of water absorbent resin (a) (g / m
in) is preferably 5 or more, more preferably 7 or more, particularly preferably 10 or more, and particularly preferably 15
As described above, it is most preferably 20 or more. Further, it is preferably 200 or less, more preferably 180 or less, particularly preferably 150 or less, more preferably 135 or less, and most preferably 120 or less. Within this range, the liquid to be absorbed (water, urine, blood or muddy water) will be more diffused, and the absorption rate will be even better.

The raw materials (monomer, polymerization initiator, internal cross-linking agent, surface cross-linking agent, etc.) and manufacturing method (polymerization method, etc.) for the water-absorbent resin (a) are the same as those for the water-absorbent resin (a). The preferred range is also the same. In order to make the gel permeation rate of the water absorbent resin (a) within the above range, (b1) a method of using the internal crosslinking agent in a usage amount range described below, and (b2) a surface crosslinking agent used amount range described below. The method used in (1), (b3) a method of using an internal cross-linking agent and a surface cross-linking agent together in the usage amount range described below, and (b4) the use of inorganic particles described below in the polymer obtained by any of the methods of b1 to b3. In the amount range, (b5) a method in which a surfactant is added to the polymer obtained by any of the methods of b1 to b3 in an amount range described later, and (b6) any of b1 to b3 For the polymer obtained by the method, a method of using inorganic particles and a surfactant in the use amount range described below can be applied. Of these methods, from the viewpoint of water absorption performance (water retention capacity, absorption capacity under pressure),
The methods (b3), (b4), (b5) and (b6) are preferable, and more preferably (b4), (b5) and (b).
6), particularly preferably (b4) and (b6).

When an internal cross-linking agent is used in the water absorbent resin (a), the amount (% by weight) used is preferably 0.01 or more, based on the total weight of the polymerizable monomer and the internal cross-linking agent. More preferably, it is 0.1 or more, and particularly preferably, 0.
It is 2 or more. Further, it is preferably 5 or less, more preferably 3 or less, particularly preferably 1 or less. When the amount of the internal cross-linking agent is within this range, the gel liquid passing rate and the absorption capacity under pressure are likely to be further improved.

When the surface-crosslinking agent is used for the water-absorbent resin (a), the amount (% by weight) is the same as that for the water-absorbent resin (a). There is no particular limitation because it can be changed variously depending on the target water absorption performance (water retention capacity, water absorption capacity, water absorption capacity under pressure, etc.), but there is no particular limitation. From the viewpoint, it is preferably 0.01 or more, more preferably 0.0, based on the weight of the polymerizable monomer.
It is 5 or more, particularly preferably 0.1 or more. Further, it is preferably 5 or less, more preferably 3 or less, particularly preferably 1 or less.

The inorganic particles used in the water-absorbent resin (a) are not particularly limited as long as they are inorganic substances and are insoluble in water, and known ones can be freely used. Also, natural inorganic substances or synthetic substances can be used. It may be any of inorganic materials, and examples thereof include oxides such as silicon oxide, aluminum oxide, iron oxide, titanium oxide, magnesium oxide and zirconium oxide. Further, these may be used in combination of two or more kinds, or may be a composite of two or more kinds. Of these, silicon oxide, aluminum oxide and titanium oxide are preferable, silicon oxide and aluminum oxide are more preferable, and silicon oxide is particularly preferable. Amorphous silicon oxide is most preferably amorphous silicon oxide.

The average particle diameter of the inorganic particles is preferably 1 nm or more, more preferably 2 nm or more, particularly preferably 5 nm or more, and most preferably 10 nm or more. Further, it is preferably 150 μm or less, more preferably 50 μm.
Or less, particularly preferably 10 μm or less, most preferably 2
μm or less. Within this range, handling is likely to be further improved, and the water-absorbent resin (a) can be uniformly mixed, so that the gel liquid passing rate is likely to be further improved.

The amount (% by weight) of the inorganic particles used is based on the weight of the polymerizable monomer, the internal crosslinking agent and the surface crosslinking agent.
It is preferably 0.002 or more, more preferably 0.01
The above is more preferable, 0.03 or more, even more preferably 0.05 or more, most preferably 0.08 or more. Further, it is preferably 10.0 or less, more preferably 4.0 or less, particularly preferably 1.8 or less, further particularly preferably 0.8 or less, most preferably 0.5 or less. Within this range, the gel flow rate tends to be further improved.

The inorganic particles can be added in the form of powder, slurry or dispersion. The inorganic particles are preferably in the state of single particles, that is, in a non-aggregated state, and it is preferable to use a slurry or dispersion of the inorganic particles.

When the inorganic particles are added to the absorbent resin (a) in the form of slurry or dispersion, water and / or a volatile solvent can be used together with the inorganic particles.
The volatile solvent preferably has a vapor pressure (mmHg) at 20 ° C. of 17.5 or more, more preferably 20.
Above, especially preferably 30 or more. Again 70
It is preferably 0 or less, more preferably 600 or less, and particularly preferably 500 or less. Examples of such a volatile solvent include alcohols (methanol, ethanol, isopropyl alcohol, etc.), hydrocarbons (hexane, cyclohexane, toluene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), ketones (acetone, methyl ethyl ketone, etc.),
Examples thereof include esters (ethyl acetate, isopropyl acetate, diethyl carbonate, etc.). When using water and a volatile solvent, the amount of water used (% by weight) is preferably 1 or more, more preferably 5 or more, and particularly preferably 10 or more, based on the total weight of water and the volatile solvent. . Further, it is preferably 99 or less, more preferably 95 or less, and particularly preferably 90 or less. When water and / or a volatile solvent is used, the amount (% by weight) of these is preferably 1 or more, more preferably 2 or more, and particularly preferably 3 or more, based on the weight of the inorganic particles. Further, it is preferably 900 or less, more preferably 700 or less, and particularly preferably 400 or less.

As the stage of mixing and treating the inorganic particles,
In the case of aqueous solution polymerization, immediately before the polymerization step, immediately after the polymerization step,
Immediately before the dehydration step (step of dehydrating up to about 10% by weight of water content), during the dehydration step, immediately after the dehydration step, immediately before the pulverizing step, immediately before the pulverizing step, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment. Immediately before the drying step (step of drying to a water content of 10% by weight or less), during the drying step, after the drying step, and the like. Of these, immediately before the polymerization step, immediately before the dehydration step, immediately after the dehydration step, immediately before the pulverization step, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment, immediately before the drying step, during the drying step and drying. It is preferable after the step, more preferably immediately before the polymerization step, immediately before the dehydration step, immediately before the pulverizing step, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately before the drying step, during the drying step and after the drying step, and especially Preferably immediately before the polymerization step, immediately before the dehydration step, immediately before the surface cross-linking treatment step, during the surface cross-linking treatment step, immediately before the drying step, during the drying step and after the drying step, and particularly preferably, immediately before the polymerization step and dehydration. Immediately before the step, immediately before the surface crosslinking treatment step and immediately before the drying step, and most preferably immediately before the surface crosslinking treatment step and immediately before the drying step.

The above water content means the content ratio (% by weight) of water with respect to the total weight of the water absorbent resin. The water content is measured by an ordinary moisture measuring instrument (for example, infrared heating type measuring instrument). For example, 5 g of a sample is weighed (WA) in a petri dish and dried in a moisture measuring instrument at 125 ± 1 ° C. for 15 minutes. From the weight loss on drying (WB) at that time, it is calculated by the following formula. Moisture content (% by weight) = (WB) × 100 / (WA)

In the case of reverse phase suspension polymerization, during the polymerization step,
Immediately after the polymerization step, during the dehydration step (during the step of dehydration up to a water content of about 10% by weight), immediately after the dehydration step, during the step of separating the water-absorbent resin obtained by the polymerization from the organic solvent used for the polymerization, surface cross-linking treatment Immediately before the step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment step, immediately before the drying step (step of drying to a water content of 10% by weight or less), during the drying step, after the drying step, and the like. Of these, immediately after the polymerization step, during the dehydration step, immediately after the dehydration step, during the step of separating the water absorbent resin obtained by the polymerization and the organic solvent used for the polymerization, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, Immediately after the surface cross-linking treatment step, immediately before the drying step, preferably during the drying step and after the drying step, more preferably immediately after the dehydration step, during the step of separating the water absorbent resin obtained by the polymerization and the organic solvent used for the polymerization. Immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment step, immediately before the drying step, during the drying step and after the drying step, particularly preferably immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, and dried. Immediately before the process and during the drying process.

The industrial device for mixing and treating the inorganic particles is not particularly limited, but for example, a conical blender, an internal mixer (Banbury mixer), a self-cleaning type mixer, a gear compounder, a screw type extruder, a screw Type kneader, mincing machine, nauter mixer, double arm type kneader, V type mixer,
Mechanical mixers such as fluidized bed mixers, turbulators, screw line blenders, ribbon mixers and mortar mixers are preferably used. These can also be used in combination. As a method of mixing and processing with these mixing devices, while stirring the polymer composed of the polymerizable monomer in the mixing device, a method of adding or spraying inorganic particles to mix and process the inorganic particles in advance. A masterbatch is prepared by adding and mixing it to a polymer composed of a polymerizable monomer at a high concentration, and the masterbatch is converted into a polymer composed of a polymerizable monomer so that a predetermined amount of inorganic particles is added. Examples thereof include a method of adding, mixing and treating.

As the surfactant used for the water absorbent resin (a), known ones described in US Pat. No. 4,331,447 can be used. Among these, an anionic surfactant and a nonionic surfactant are preferable from the viewpoint of the water absorption performance (water retention capacity, absorption capacity under pressure) and gel flow rate of the water absorbent resin (a). As this preferable anionic surfactant, (poly) oxyethylene (degree of polymerization = 1 to 100) sodium lauryl sulfate, (poly) oxyethylene (degree of polymerization = 1 to 100) sodium lauryl ether acetate, (poly) oxyethylene (Degree of polymerization = 1
˜100) disodium lauryl sulfosuccinate and (poly) oxyethylene (polymerization degree = 1 to 100) sodium lauryl ether phosphate.

As the preferred nonionic surfactant, lauryl alcohol ethylene oxide addition (polymerization degree = 1-20), oleyl alcohol ethylene oxide addition (polymerization degree = 1-10), polyethylene glycol monostearate ( Degree of polymerization = 1 to 20), distearic acid (poly) ethylene glycol (degree of polymerization = 1
~ 30), (poly) oxyethylene (degree of polymerization = 1-2
5) Lauric acid (mono- / di-) ester, (poly) oxyethylene (degree of polymerization = 1-50) Stearic acid (mono- / di-) ester, (poly) oxyethylene (degree of polymerization = 1-18) Oleic acid (mono- / di-) ester,
(Poly) oxyethylene (degree of polymerization = 1 to 50) Dioleic acid methyl glucoside, (poly) oxyethylene (degree of polymerization = 1 to 20) nonylphenyl ether, polydimethylsiloxane {viscosity (cSt) = 0.5 to 1 × 10 ⁸ }
(Poly) oxyethylene (degree of polymerization = 1 to 50) modified product,
Polydimethylsiloxane {viscosity (cSt) = 0.5 to 1
× 10 ⁸ } (Poly) oxyethylene (degree of polymerization = 1 to 5)
0) · (Poly) oxypropylene (degree of polymerization = 1 to 50)
Modified product, (poly) oxyethylene / polyoxypropylene block polymer (weight average molecular weight = 160 to 1000)
0)}. In addition, you may use together 1 type (s) or 2 or more types.

When the surfactant is used, the amount (% by weight) is the amount of the polymer composed of the polymerizable monomer, from the viewpoints of water absorption performance (water retention capacity, absorption capacity under pressure) and gel flow rate. It is preferably 0.001 or more, more preferably 0.005 or more, and particularly preferably 0.01 based on the weight.
As described above, it is most preferably 0.03 or more, preferably 10 or less, more preferably 5 or less, particularly preferably 3 or less, and most preferably 1 or less.

Regarding the method of adding the surfactant, for example, it can be produced by adding and mixing a surfactant or an aqueous solution of the surfactant with a polymer composed of a polymerizable monomer. It is more preferable to add and mix the surfactant in the form of an aqueous solution from the viewpoint that the surfactant can be more uniformly added to the polymer composed of the polymerizable monomer.

When the surfactant is added in the form of an aqueous solution, the concentration (% by weight) of the aqueous solution is 0 from the viewpoint of the blocking property of the water absorbent resin (a) and the uniformity of the surfactant at the time of addition. It is preferably 1 or more, more preferably 1 or more, and particularly preferably 5 or more. Again 8
It is preferably 0 or less, more preferably 50 or less, and particularly preferably 30 or less. The method of adding the surfactant is not particularly limited, but is, for example, JP-A 09-136.
Known methods described in Japanese Patent No. 966, etc. can be applied.

The water retention capacity (g / g) of the water absorbent resin (a) is
It is preferably 25 or more, more preferably 28 or more, particularly preferably 30 or more, more preferably 33 or more, and most preferably 35 or more. Further, it is preferably 50 or less, more preferably 48 or less, particularly preferably 45 or less, more preferably 42 or less, most preferably 40 or less.
It is the following. Within this range, the absorption rate of the liquid to be absorbed is likely to be further improved under load. In order to keep the water retention capacity of the water absorbent resin (a) within the above range, the internal crosslinking agent is used in an amount of 0.1% by weight or more and 3% by weight or less based on the total weight of the polymerizable monomer and the internal crosslinking agent. Method and / or surface cross-linking agent based on the weight of the polymerizable monomer at 0.0
A method of using 5% by weight or more and 3% by weight or less can be applied.

Water absorption capacity (g / g) of water absorbent resin (a)
Is preferably 30 or more, more preferably 35 or more,
It is particularly preferably 40 or more, and most preferably 45 or more. Further, it is preferably 70 or less, more preferably 65 or less, particularly preferably 60 or less, and most preferably 55 or less. Within this range, the absorption rate of the liquid to be absorbed is likely to be further improved under normal pressure. In order to adjust the absorption capacity of the water absorbent resin (a) to the above range, the internal cross-linking agent is adjusted to 0 ..% based on the total weight of the polymerizable monomer and the internal cross-linking agent.
A method of using 1% by weight or more and 3% by weight or less, and / or a method of using the surface crosslinking agent in an amount of 0.05% by weight or more and 3% by weight or less based on the weight of the polymerizable monomer can be applied.

Water absorption capacity under pressure of the water absorbent resin (a) (g /
g) is preferably 20 or more, more preferably 22 or more, particularly preferably 25 or more, and most preferably 30 or more. Further, it is preferably 50 or less, more preferably 4
5 or less, particularly preferably 40 or less, most preferably 35
It is the following. Within this range, the absorption rate of the liquid to be absorbed is more likely to be improved under load. In order to make the absorbency against pressure of the water absorbent resin (a) within the above range, the internal cross-linking agent is 0.1 wt% or more and 3 wt% or more based on the total weight of the polymerizable monomer and the internal cross-linking agent. Based on the weight of the polymerizable monomer, the method used below, and / or the surface cross-linking agent,
A method of using 0.05% by weight or more and 3% by weight or less can be applied.

The shape of the water-absorbent resins (a) and (a) is not particularly limited, but it is preferably granular, and more preferably spherical, granular, crushed, acicular, flaky and primary particles thereof are fused with each other. It is in a cohesive state as if worn. The size of the water-absorbent resin (a) is not particularly limited, but a particle size of 50 μm or more (preferably 75 μm or more, more preferably 150 μm or more) and 1000 μm or less (preferably 900 μm or less, more preferably 850 μm or less) is used. The content of the particles is preferably 90% by weight or more, more preferably 93% by weight or more, and particularly preferably 95% by weight or more of the total weight of the water absorbent resin (A). The same applies to the size of the water absorbent resin (a).

The sizes of the water-absorbent resins (a) and (a) were measured by a low tap test sieve shaker and JIS Z880.
Using a 1-2000 standard sieve, the method described in Perry's Chemical Engineers Handbook, 6th edition (MacGlow-Hill Book Company, 1984, p. 21) is used (hereinafter, the measurement of the particle diameter is performed by the book). It depends on the method.).

Additives may be added to the absorbent resin (A) and / or (A). Examples of the additives include antiseptics, antifungal agents, antibacterial agents, antioxidants, reducing agents,
UV absorbers, acids, colorants, fragrances, deodorants, inorganic powders and fibrous substances are used.

Examples of the preservative include preservatives such as salicylic acid, sorbic acid, dehydroacetic acid and methylnaphthoquinone, and bactericidal agents such as chloramine B and nitrofurazone. Examples of the fungicide include butyl p-oxybenzoate and the like. As an antibacterial agent,
Examples thereof include benzalkonium chloride salt and chlorhexidine gluconate.

Examples of the antioxidant include hindered phenol antioxidants {triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6- Hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3
-(3,5-di-t-butyl-4-hydroxyphenylpropionate and 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, etc.}, amine antioxidant {n- Butylamine, triethylamine, diethylaminomethyl methacrylate, etc.}
And mixtures of two or more of these.

Examples of the reducing agent include sulfite (sodium sulfite, ammonium sulfite, etc.), bisulfite (sodium bisulfite, ammonium bisulfite, etc.), ascorbic acid, ferrous salt (ferrous chloride, ferric sulfate, etc.). Ferrous iron), cuprous salt (cuprous chloride, cuprous sulfate, etc.), amine (ammonia,
Monoethanolamine, etc.), reducing sugars (glucose, etc.) and the like.

Examples of the ultraviolet absorber include benzotriazole ultraviolet absorbers {2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-
Di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2-
(3,5-di-t-amyl-2-hydroxyphenyl)
Benzotriazole etc.}, triazine UV absorber {2
-(4,6-Diphenyl-1,3,5-triazine-2
-Yl) -5-[(hexyl) oxy] -phenol etc., benzophenone ultraviolet absorber {2-hydroxy-
4-n-octyloxybenzophenone, etc., an oxalic acid anilide ultraviolet absorber {2-ethoxy-2′-ethyloxalic acid bisanilide, etc.}, and a mixture of two or more thereof.

Examples of the acid include inorganic acids (hydrochloric acid, sulfuric acid, phosphoric acid, monosodium phosphate, etc.), organic acids (acetic acid, propionic acid, butyric acid, succinic acid, lactic acid, malic acid, tartaric acid, citric acid, hippuric acid, Glycine, alanine, fumaric acid, etc.) and the like. Examples of colorants include inorganic pigments such as carbon black, titanium oxide, red iron oxide, red lead, rose red, dark blue and ferrite, organic pigments such as azo lake, benzimidazolone and phthalocyanine, and dyes such as nigrosine and aniline. Etc. Examples of the fragrance include natural flavors such as musk, Avies oil and turpentine, and synthetic flavors such as menthol, citral, p-methylacetophenone and floral. Examples of the deodorant include activated carbon, zeolite, silica, flavonoid, cyclodextrin and the like.

Examples of the inorganic powders include calcium carbonate, kaolin, talc, mica, bentonite, clay, sericite, asbestos, carbon black, glass (powder, fiber and balloon), shirasu, graphite, metal (iron, copper, Aluminum and gold), ceramics (barium titanate, silicon carbide, carbon nitride, etc.)
And asbestos. Any form of inorganic powder can be used. Average particle size of inorganic powder (μ
m) is preferably 0.1 or more, more preferably 1 or more, and particularly preferably 2 or more, from the viewpoint of powder fluidity and moisture absorption blocking property of the water-absorbent resin (a) and / or (a). Further, it is preferably 1000 or less, more preferably 100 or less, and particularly preferably 50 or less.

The fibrous material is not particularly limited as long as it is fibrous, but natural fibers, artificial fibers and synthetic fibers, mixtures thereof, regenerated fibers thereof and the like can be used.
As the natural fiber, for example, cotton, absorbent cotton, sawdust,
Examples thereof include straw, grass charcoal, wool, microfibrils, bacterial cellulose, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP) and flats pulp. Examples of the artificial fiber include rayon and acetate. Examples of the synthetic fiber include polyolefin fiber (polyethylene fiber, polypropylene fiber and polyethylene / polypropylene composite fiber, etc.), polyester fiber (polyethylene terephthalate fiber and polyethylene terephthalate / polyethylene isophthalate copolymer composite fiber, etc.), polyolefin / polyester composite fiber. (Polyethylene / polyethylene terephthalate composite fiber and polypropylene / polyethylene terephthalate composite fiber, etc.), Polyamide fiber (polyterephthalic acid ethylenediamide fiber, polyisoterephthalic acid ethylenediamide fiber, polyterephthalic acid propylenediamide fiber, polyisoterephthalic acid propylenediamide fiber, etc.) ), Polyacrylic fibers (polybutyl acrylate fibers and 2-ethylhexyl polyacrylate)維等), and polyacrylonitrile fibers.
Of these, natural fibers and synthetic fibers are preferable, and natural fibers are more preferable.

When an additive is used, the content (% by weight) of the additive is not particularly limited, but it may be a preservative, a fungicide, an antibacterial agent, an antioxidant, a reducing agent, an ultraviolet absorber, an acid, an aroma. The content of the agent and the deodorant is preferably 0.00001 or more, and more preferably 0.00005 or more, based on the weight of the water-absorbent resins (a) and (a), respectively. Further, it is preferably 10 or less, more preferably 5 or less. The contents (% by weight) of the colorant, the inorganic powder and the fibrous substance are respectively water absorbent resins (a) and (a).
0.1 or more, more preferably 0.2 or more, and preferably 25 or less, based on the weight of
More preferably, it is 15 or less.

The absorbent article of the present invention comprises a water absorbent resin (a)
And the water absorbent resin (a), the absorbent layer (A) containing the water absorbent resin (a) and the water absorbent resin from the viewpoint of dryness (dryness) and leak resistance. An absorber layer (B) containing a resin (a), or (a)
An absorbent article containing the absorber layer (C) containing (1) and (A) and optionally (A) and / or (B) is preferable. That is, an absorbent article containing (A) and (B), an absorbent article containing (C), an absorbent article containing (C) and (A), and (C) and (B). ) And an absorbent article comprising (C), (A) and (B)
An absorbent article comprising and is preferred. The absorber layer (C) containing the water-absorbent resin (A) and the water-absorbent resin (A) contains a mixed water-absorbent resin (A) in which (A) and (A) are mixed. Absorber layer, absorber layer mainly containing (A) and absorber layer mainly containing (A), and absorption containing (A) Although any form such as an absorber layer in which the absorber layer (B) containing the body layer (A) and the absorber layer (B) is integrated may be used, the forms of and are preferable. Here, the term "integral" refers to a state in which one layer and one layer overlap each other to form one layer as a whole, or a state in which one layer and one layer are arranged in parallel or where one layer surrounds the other on the same plane. means.

The absorbent layer preferably comprises a water absorbent resin and a fibrous material. The fibrous material is not particularly limited as long as it is fibrous, but natural fibers, artificial fibers and synthetic fibers, mixtures thereof, regenerated fibers thereof, and the like can be used. Examples of natural fibers include cotton,
Absorbent cotton, sawdust, straw, grass charcoal, wool, microfibrils, bacterial cellulose, hardwood kraft pulp (L
KP), softwood bleached kraft pulp (NBKP), and flats pulp.

Examples of artificial fibers include rayon and acetate. Examples of synthetic fibers include polyolefin fibers (polyethylene fibers, polypropylene fibers, polyethylene / polypropylene composite fibers, etc.), polyester fibers (polyethylene terephthalate fibers, polyethylene terephthalate / polyethylene isophthalate copolymer composite fibers, etc.), polyolefins, etc.
Polyester composite fiber (polyethylene / polyethylene terephthalate composite fiber and polypropylene / polyethylene terephthalate composite fiber, etc.), polyamide fiber (polyterephthalic acid ethylenediamide fiber, polyisoterephthalic acid ethylenediamide fiber, polyterephthalic acid propylene diamide fiber and polyisoterephthalic acid propylene) Diamide fibers and the like), polyacrylic fibers (polybutyl acrylate fibers and poly (2-ethylhexyl acrylate fibers) and the like, and polyacrylonitrile fibers and the like.

The absorber layer (A), the absorber layer (B), and the absorber layer (C) which is included as necessary, based on the area of the largest projection plane having the largest area among the projection planes on which the absorber layer is arbitrarily projected. The total content (g / m ² ) of the water-absorbent resins (a) and (a) present in () is preferably 4 or more, more preferably 10 or more, particularly preferably 20 or more, most preferably 30 or more. And preferably 1000 or less,
It is more preferably 900 or less, particularly preferably 800 or less, and most preferably 700 or less. The total content (g / m ² ) of the water-absorbent resins (a) and (b), particularly in the case of hygiene products, is preferably 4 or more, more preferably 10 or more, particularly preferably 50 or more, most preferably Is 70 or more, preferably 500 or less, more preferably 300 or less, particularly preferably 250 or less,
Most preferably, it is 200 or less. When the total content is within this range, the water retention capacity of the absorber layer becomes higher, and there is a tendency to exhibit further excellent dryness.

The fibrous substance content (g / m ² ) contained in the absorber layer (A) or (B) is preferably 10 or more, more preferably 20 or more, particularly preferably 30 or more, and most preferably 40. It is above, and preferably 1000 or less, more preferably 900 or less, and particularly preferably 80.
It is 0 or less, and most preferably 700 or less. In the case of hygiene products, the content (g / m ² ) is preferably 10 or more, more preferably 20 or more, particularly preferably 30 or more, most preferably 40 or more, and 400
The following is preferable, more preferably 300 or less, particularly preferably 250 or less, and most preferably 200 or less. When the content of the fibrous material is within this range, the absorbent layer tends to exhibit more excellent dryness.

The absorbent layer (A) containing the water-absorbent resin (A), the absorbent layer (B) containing the water-absorbent resin (A), and (A) and (A) if necessary. Among the absorbent articles having the absorbent layer (C) contained therein, based on the total weight of the absorbent resin (A) contained in the absorbent layer (A) or (C), ) 70% by weight or more 1
An absorbent article having an outermost amount (a) of not more than 00% by weight is more preferable. When the absorbent resin (a) is present in the outermost portion (a) within the above range, the anti-leakage property tends to be further improved. Here, the outermost portion (a) includes, in the maximum projection surface having the largest area of the projection surfaces on which the absorber layer is arbitrarily projected, 50% of the total area of the maximum projection surface, and the outline of the maximum projection surface. Is a portion obtained by cutting a portion of the absorber layer corresponding to a region having an evenly spaced width with a plane perpendicular to the maximum projection plane.

As the method for obtaining the absorber layer, a method of simultaneously mixing a mixture of the water-absorbent resins (a) and (a) and a fibrous substance in an air stream and laminating the fibers, and a mixture of (a) and (a) And a fibrous material are mixed in advance and laminated in an air stream, a method of laminating a mixture of (a) and (a) on the fibrous material, and further laminating a fibrous material, A method in which water-absorbent resins (a) and (a) are separately and sequentially mixed with a fibrous material in an air stream and then laminated, and (a) and (a) are separately mixed with the fibrous material in advance, Examples include a method of sequentially laminating fibers in an air stream, a method of laminating (a) and (a) separately on a fibrous material, and further laminating a fibrous material. Of these methods, (A) and (A) can be added separately, and the positions of the absorber layers (A) and (B) and, if necessary, (C) in the entire absorber in the absorbent article of the present invention From the perspective that you can adjust
The methods of and are preferable, and the method of is more preferable. The device used for these methods is not particularly limited, and a normal device can be used, and examples thereof include a drum forming device.

The absorbent article containing the absorbent resin (a) in the above range in the outermost part (a) can be obtained by the following method. After separately producing (A) and (B), the content of (A) in the outermost (a) is adjusted to the above range (A).
And (B) are overlapped. A method of simultaneously forming (A) and (B) so that the content of (a) in the outermost portion (a) falls within the above range. After forming (A), the outermost portion (a) is left, the central region is removed by cutting, and the absorber layer (B) is formed in the removed central region. After forming (B), a method of forming (A) so that the content of (A) in the outermost (a) is within the above range. Also,
The method for forming these absorber layers may be a continuous method or a batch method, but the continuous method is preferable from the viewpoint of productivity. Of these, from the viewpoint of the leak resistance and productivity of the absorbent article,
The method of is preferable.

The absorber layer (A) and the absorber layer (B), or the absorber layer (C) and (A) and / or (B) if necessary.
In the absorbent article containing, the content of each layer is as follows. When the absorber layer (A) is used, the content (% by weight) of the absorber layer (A) is preferably 5 or more based on the total weight of (A), (B) and (C), and further, It is preferably 10 or more, particularly preferably 15 or more, and most preferably 20 or more. Also, 50 or less is preferable,
More preferably 40 or less, particularly preferably 35 or less,
Most preferably, it is 30 or less. When the absorber layer (B) is used, the content (% by weight) of the absorber layer (B) is
50 based on the total weight of (A), (B) and (C)
It is preferably at least 55, more preferably at least 55, particularly preferably at least 60, and most preferably at least 65. Further, it is preferably 95 or less, more preferably 90 or less, particularly preferably 85 or less, and most preferably 80 or less.
When the absorber layer (C) is used, the content (% by weight) of the absorber layer (C) is preferably 0.1 or more, more preferably 3 or more, particularly preferably 5 or more, and most preferably 8
That is all. Further, it is preferably 30 or less, more preferably 25 or less, particularly preferably 20 or less, and most preferably 15 or less.

In the absorbent article of the present invention, the content (% by weight) of the water absorbent resin (A) is preferably 5 or more, and more preferably based on the total weight of the absorbent resins (A) and (A). Is 10 or more, particularly preferably 15 or more, and most preferably 20 or more. Also, 90 or less is preferable,
More preferably 70 or less, particularly preferably 50 or less,
Most preferably, it is 30 or less. When the content of (A) is within this range, the leakage resistance tends to be further improved.

In the absorbent article of the present invention, the content (% by weight) of the water absorbent resin (A) is preferably 10 or more, and more preferably based on the total weight of the absorbent resins (A) and (A). Is 30 or more, particularly preferably 50 or more, and most preferably 70 or more. Further, it is preferably 95 or less, more preferably 90 or less, particularly preferably 85 or less, and most preferably 80 or less. When the content of (a) is within this range, the dryness, blocking resistance and leak resistance tend to be further improved.

The content (% by weight) of the water absorbent resin (A) and the water absorbent resin (A) is preferably 10 or more, based on the total content of (A), (A) and the fibrous material, and It is preferably 20 or more, particularly preferably 30 or more, and most preferably 40 or more. Further, it is preferably 95 or less, more preferably 80 or less, particularly preferably 75 or less, and most preferably 70 or less. When the contents of (a) and (a) are in this range, the water absorption speed and the leakage resistance tend to be further improved.

The content (% by weight) of the fibrous material is (a),
Based on the total content of (a) and the fibrous material, it is preferably 5 or more, more preferably 20 or more, particularly preferably 25 or more, and most preferably 30 or more. Further, it is preferably 90 or less, more preferably 80 or less, particularly preferably 70 or less, and most preferably 60 or less. When the content of the fibrous material is in this range, the diffusion speed of the substance to be absorbed in the absorbent article tends to be improved, and the absorption amount of the absorbent article tends to be further improved.

The absorbent articles comprising the water-absorbent resins (A) and (A) of the present invention are sanitary items (for example, disposable diapers (diapers for children's paper and diapers for adults), napkins (sanitary napkins), paper towels. , Pads (pads for incontinence and surgical underpads, etc.), pet sheets (pet urine absorption sheets, heat retention sheets, etc.), and various household and industrial absorption sheets other than sanitary items {for example, freshness preservation A sheet, a drip absorption sheet, a paddy rice seedling sheet, a concrete curing sheet, a sheet for preventing running of water such as cables, etc.} and the like. Among these, the absorbent article of the present invention has excellent resistance to leakage, and can reduce discomfort during use and discomfort, so that the hygiene article {paper diaper,
Preferred as a napkin, pad, pet sheet}, and various household and industrial absorbent sheets (freshness-maintaining sheet, drip absorbent sheet, paddy rice seedling sheet), and as sanitary goods {paper diapers, napkins, pads, pet sheets} It is preferable and also suitable as a hygiene article {paper diaper, napkin, pad}.

As the structure of the sanitary article, for example, a top sheet having a liquid-permeable top sheet is disposed, a bottom layer is provided with a liquid-impermeable back sheet, and an intermediate layer between them is a water-absorbent resin and a fiber. Structure (K1) in which an absorbent body layer (1 layer) composed of shaped objects (natural fiber, artificial fiber, synthetic fiber or a mixture thereof) is arranged, a liquid permeable surface sheet is arranged in the uppermost layer, and the lowermost layer is arranged. The liquid-impermeable backing sheet is placed on the sheet, and 2 to 4 absorbent layers similar to those in the case of (K1) are stacked as the intermediate layer to provide a laminated absorbent layer. In the structure (K2) in which at least one liquid-permeable intermediate sheet is provided between layers, and (K1) or (K2) structure, between the uppermost layer and the intermediate layer and / or the intermediate layer. Structure (K3) (where at least one liquid-permeable intermediate sheet is disposed between the lowermost layer and Water when absorbed into the absorbent article, urine tends to improve the diffusibility of the absorbent product such as feces and menses.) And the like. Of these, (K3) is preferable from the viewpoint of leakage of the absorbent from hygiene products.

As a specific example of a sanitary article, a paper diaper will be explained. A liquid-permeable top sheet is placed on the surface of the hygiene article, and a liquid-impermeable back sheet is placed on the back surface.
If necessary, a liquid permeable sheet may be placed on the upper or lower part of the absorber layer, and a gathering device, a tape for attaching to a human body, or the like may be further provided to finish a disposable diaper or the like.

Examples of the liquid-permeable surface sheet used for hygiene products include water, seawater, muddy water, which is absorbed by absorbent articles,
The material to be absorbed such as urine, stool and menstrual blood is not particularly limited as long as it easily penetrates its thickness and is absorbed by the absorbent layer. A non-woven fabric, a woven fabric or a knitted fabric made of a thermoplastic resin or the like, and a perforated film made of a thermoplastic resin or the like are preferably used. The hole diameter (mm) of the perforated film is preferably 0.01 or more, more preferably 0.02 or more, and particularly preferably 0.03 or more. Further, it is preferably 300 or less, more preferably 200 or less, and particularly preferably 100 or less.

Examples of the thermoplastic resin include polyolefins (polyethylene, polypropylene and polyethylene / polypropylene copolymers), polyesters (polyethylene terephthalate and polyethylene terephthalate / polyethylene isophthalate copolymers), polyolefin / polyester copolymers ( Polyethylene / polyethylene terephthalate copolymer and polypropylene
Polyethylene terephthalate copolymer etc.), polyamide (polyterephthalic acid ethylenediamide, polyisoterephthalic acid ethylenediamide, polyterephthalic acid propylenediamide and polyisoterephthalic acid propylenediamide fiber etc.), polyacryl (polyacrylate butyl fiber and polyacryl) Acid 2-ethylhexyl fiber and the like) and polyacrylonitrile fiber and the like. Among these liquid-permeable topsheets, non-woven fabrics, woven fabrics and knitted fabrics made of thermoplastic resin are preferable, more preferably non-woven fabrics made of thermoplastic resin, particularly preferably polyolefin resin, polyester resin or polyolefin-polyester A non-woven fabric made from a polymer.

The thickness (μm) of the liquid-permeable topsheet is not particularly limited, but is preferably 5 or more,
From the viewpoint of the diffusibility of the substance to be absorbed and the thickness and flexibility of the absorbent article, it is more preferably 10 or more, particularly preferably 20 or more, and most preferably 30 or more. Again 500
It is preferably 0 or less, more preferably 100 from the viewpoint of the diffusibility of the substance to be absorbed and the thickness and flexibility of the absorbent article.
0 or less, particularly preferably 750 or less, most preferably 5
It is 00 or less.

Examples of the liquid-impermeable back sheet used for sanitary goods include water, seawater, muddy water absorbed in absorbent articles,
There is no particular limitation as long as the absorbable material such as urine, feces and menstrual blood can be prevented from seeping out to the back surface. For example, a sheet made of the above-mentioned thermoplastic resin or the like is used. Of these, a sheet made of polyolefin is preferable, more preferably a sheet made of polyethylene, polypropylene or polyethylene-polypropylene,
Particularly preferred is a sheet made of polyethylene.

The thickness (μm) of the back sheet is not particularly limited, but is preferably 5 or more, and more preferably 10 from the viewpoint of the thickness and flexibility of the absorbent article.
Above, particularly preferably 20 or more, most preferably 30 or more, and preferably 5000 or less, more preferably 100 from the viewpoint of the thickness and flexibility of the absorbent article.
0 or less, particularly preferably 750 or less, most preferably 5
It is 00 or less.

As the liquid-permeable intermediate sheet used as necessary, the same ones as those used for the liquid-permeable surface sheet can be used. The liquid-permeable intermediate sheet is for facilitating the permeation of the absorbent article such as water, seawater, muddy water, urine, feces and menstrual blood, which is easily absorbed and diffused in the absorbent layer. It is a thing. The materials and types of gathers and mounting tapes are not particularly limited, and known materials used for conventional absorbent articles can be used.

When the absorbent article of the present invention is a disposable diaper,
The leak resistance (g) of the absorbent body of this disposable diaper is preferably 200 or more, more preferably 220 or more, particularly preferably 240 or more, and most preferably 250 or more. It is preferably 1,000 or less, more preferably 900
Or less, particularly preferably 800 or less, most preferably 70 or less.
It is 0 or less. When the moisture resistance is in this range, the dryness and the moisture resistance of the absorbent article tend to be further improved.

The leakage resistance is measured by the following method. That is, an absorber (a component part of a paper diaper composed of a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber layer) is cut into a rectangle from a paper diaper using scissors or the like. At this time, the absorbent layer contained in the diaper must be cut out so that most (preferably all) of the absorbent layer is contained. Further, the top sheet and the back sheet are cut out so as to be 1 cm larger from the ends of the four sides of the absorber layer. 0.5cm from the end of the long side of the rectangle
Part of the heat sealer (eg FUJI IMPU
LSE CO. LTD. Made, model number FI-K600-5W
Type) and heat seal (for example, about 180 ℃ x 2 seconds)
To do. (However, nothing is applied to the end of the cut short side of the absorber.) Next, the back side sheet is in contact with the plate inclined at 45 degrees so that the short side of the rectangle (SH <cm>) Place one end of the top on the top and the other end of the short side on the bottom.

Then, from the other end of the short side to the long side (L
H <cm>) 10% inside, and using a glass tube with an inner diameter of 1 cm to the center of the short side, use physiological saline (0.9 wt% sodium chloride aqueous solution) Is injected at a rate of 400 g / min. The liquid is poured from about 1 cm away from the surface of the absorber, and it is allowed to fall naturally without applying pressure. After injecting saline,
The time from the other end of the short side until the saline starts to leak (e
<Second>) is measured, and the leak resistance (g) is determined from the following equation.
The measurement is performed three times and the average value is calculated. Moreover, all measurements are performed in an atmosphere of 25 ± 3 ° C. and 60 ± 5 RH%. Further, in the present measuring method, if the length of the short side of the cut absorber is 5 cm or less, physiological saline leaks from the side portion during the measurement, and the evaluation cannot be performed accurately, which is not preferable.

[0100]

[Equation 7]

[0101]

EXAMPLES The usefulness of the present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, parts means parts by weight,
% Means% by weight. <Synthesis Example 1> Acrylic acid 81.8 was placed in a glass reaction container.
Parts, 0.1 part of N, N′-methylenebisacrylamide and 241 parts of deionized water were charged, and the temperature of the contents was kept at 1 to 2 ° C. while stirring and mixing. Next, nitrogen is flowed into the liquid layer of the contents to reduce the dissolved oxygen amount in the liquid layer to 0.5 ppm.
(Central Scientific Co., Ltd. DO meter UC-12-
(Measured with SOL type), and then sealed, 5% 2,2 '
-2.8 parts of aqueous azobisamidinopropane dihydrochloride solution, 1 part of 1% aqueous hydrogen peroxide, and 1%
Polymerization was initiated by adding and mixing 1.2 parts of the ascorbic acid aqueous solution (polymerization initiation temperature of about 3 ° C.).

Subsequently, polymerization was carried out in a sealed atmosphere at 50 to 60 ° C. for about 8 hours while polymerizing, and then 300 parts of this water-containing polymer was kneaded with an internal mixer to obtain 48 parts.
% Sodium hydroxide aqueous solution (62.3 parts) was added to neutralize 72 equivalent% of the carboxyl groups. In addition, JIS K
The degree of neutralization calculated from the acid value measured according to 0113-1997 (using 0.1 N potassium hydroxide aqueous solution as a titrant) was 70.1 equivalent%. Then, shred into 2 to 5 mm with an internal mixer, 150
After drying in a ventilated band dryer under the conditions of ℃ and wind speed of 2.0 m / sec, the dried product is crushed and then standard sieve (JIS Z8801) is used.
-2000) to remove particles of 850 μm or larger and particles of 150 μm or smaller by 150 to
A water absorbent resin (A-1) was obtained by adjusting the particles having a particle diameter of 850 μm. This water absorbent resin
Regarding 1), the gel flow rate is 0.01 ml / min,
The water retention capacity was 54 g / g, the water absorption capacity was 62 g / g, and the water absorption capacity under pressure was 8 g / g.

<Synthesis Example 2> 100 parts of the water absorbent resin (A-1) prepared in Synthesis Example 1 was kept at 20 to 30 ° C. under high speed stirring to obtain 0.75% of ethylene glycol diglycidyl ether (nagase Seibun Kogyo Co., Ltd., trade name: Denacol EX810) Add 20 parts of water / methanol mixed solution (water / methanol [volume ratio] = 20/80) and continue to 2
After mixing for about 30 minutes while maintaining at 0 to 30 ° C, 140
The water-absorbent resin (a-
2) was obtained. Regarding the water absorbent resin (A-2), the gel flow rate was 3 ml / min, the water retention capacity was 38 g / g, the water absorption capacity was 55 g / g, and the water absorption capacity under pressure was 18 g / g.

<Synthesis Example 3> A water-absorbent resin (A-3) was prepared in the same manner as in Synthesis Example 2 except that ethylene glycol diglycidyl ether was changed to glycerin polyglycidyl ether (Nagase Kasei Kogyo KK, trade name: Denacol EX314).
Got Regarding the water absorbent resin (A-3), the gel flow rate was 0.6 ml / min, the water retention capacity was 37 g / g, the water absorption capacity was 54 g / g, and the water absorption capacity under pressure was 14 g / g.

<Synthesis Example 4> A water absorbent resin (A-1) was obtained in the same manner as in Synthesis Example 1 except that the amount of N, N'-methylenebisacrylamide was changed from 0.1 part to 0.25 part. It was
0.75% ethylene glycol diglycidyl ether (Nagase Chemicals Co., Ltd., trade name: Denacol EX810) water / methanol mixture under high speed stirring while maintaining 100 parts of the water absorbent resin (a-1) at 20 to 30 ° C. 20 parts of a solution (water / methanol [volume ratio] = 20/80) was added, and the mixture was continuously mixed for about 30 minutes while maintaining the temperature at 20 to 30 ° C., followed by reacting at 140 ° C. for 30 minutes to obtain a water-absorbent resin (- 2) was obtained. Regarding the water absorbent resin (a-2),
Gel flow rate is 5 ml / min, water retention is 34 g /
g, water absorption capacity is 56 g / g, water absorption capacity under pressure is 26 g / g
It was g.

<Synthesis Example 5> 208 parts of acrylic acid and 1 part of water
Add to the mixture with 3.5 parts while cooling to below 10 ° C.
% Sodium hydroxide aqueous solution 346.0 parts was added. 0.1 part of potassium persulfate, 0.02 part of sodium hypophosphite and ethylene glycol diglycidyl ether (trade name: Denacol EX81, manufactured by Nagase Chemicals Co., Ltd.)
0) 0.1 part was added and the temperature was adjusted to 5 to 10 ° C to prepare an aqueous monomer solution. Then, in a four-necked round bottom flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction tube, 624 parts of cyclohexane was put, and polyoxyethylene octyl phenyl ether phosphate ester (Daiichi Kogyo Seiyaku Co., Ltd., (Product name: Price Surf A210G)
After 1.6 parts was added and dissolved, nitrogen gas was introduced while stirring at 400 rpm.

Then heat to 75 ° C. and 400 rpm
While stirring, the above monomer aqueous solution maintained at 5 to 10 ° C. was introduced from the liquid layer together with nitrogen gas at a substantially constant rate for 60 minutes. At this time, the oxygen concentration in the flask was 10
Keep at ~ 30 ppm. After completion of the introduction of the aqueous monomer solution, polymerization was further carried out at 75 ° C. for 30 minutes while stirring at 400 rpm, and then water was removed by azeotropic distillation with cyclohexane,
When stirring was stopped at the time when the water content of the produced polymer reached about 20% (the water content was a value calculated from the amount of removed water), the polymer particles settled, and thus the polymer particles were separated by decantation. Polymer particles were obtained by separating from cyclohexane. 40 parts of the obtained polymer particles (dry basis, 130 ° C.)
X 30 minutes dry value) and 140 parts of cyclohexane were placed in an eggplant flask, and glycerin polyglycidyl ether (Nagase Kasei Kogyo Co., Ltd., trade name: Denacol EX31) was placed in the flask.
4) After adding 3.4 parts of a 5% methanol solution, the mixture was heated at 60 ° C. and kept for 30 minutes, and further kept under reflux of methanol / cyclohexane for 30 minutes. Then, the polymer particles were obtained by filtration and dried under reduced pressure at 80 ° C. to obtain a water absorbent resin (A-4). Regarding the water absorbent resin (A-4), the gel flow rate was 0.2 ml / min, the water retention capacity was 34 g / g, the water absorption capacity was 56 g / g, and the water absorption capacity under pressure was 12 g / g.

<Synthesis Example 6> 50 parts of the water-absorbent resin (a-2) obtained in Synthesis Example 4 and silica (Shionogi Pharmaceutical Co., Ltd., trade name: Carplex FPS-1, average particle size of about 8 μm)
m) 0.1 part was thoroughly shaken in a vinyl bag (about 25 ° C. for 5 minutes) and homogenized to obtain a water absorbent resin (A-3). Regarding the water absorbent resin (A-3), the gel flow rate was 72 ml / min, the water retention capacity was 34 g / g,
The water absorption capacity was 59 g / g, and the water absorption capacity under pressure was 18 g / g.

<Synthesis Example 7> 50 parts of the water absorbent resin (A-2) obtained in Synthesis Example 4 was dissolved in a silicon oxide colloidal solution (SO,
Clariant, trade name: Klebosol 3
0CAL25, solid content concentration 30%, average particle size about 25n
m) / polyether-modified silicone oil (ES, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-351), mixed solution of methanol (SO / ES / methanol [weight ratio] =
2.7 parts of 24.8 / 0.9 / 74.3) were added and mixed with an internal mixer at about 25 ° C. for 10 minutes, and then dried at 100 ° C. for 30 minutes to obtain a water absorbent resin (a). -4) was obtained. Regarding the water absorbent resin (A-4), the gel flow rate was 189 ml / min, and the water retention capacity was 34 g / min.
g, water absorption capacity is 59 g / g, water absorption capacity under pressure is 24 g /
It was g.

Water-Absorbent Resins (A-1) of Synthesis Examples 1 to 7
Using (A-4) and (B-2) to (B-4), the absorber layers (AB-1) to (AB-4) and (A-
1)-(A-2) and (B-1)-(B-2) were created. <Preparation Example 1> 4.5 parts of water-absorbent resin (A-1) and 8 parts of Japanese Pharmacopoeia absorbent cotton (Kawamoto Sangyo Co., Ltd.) were fibrillated by hand about 500 times while mixing until the appearance was uniform. Then, a mixture (X) was obtained. Similarly, the water absorbent resin (A-2) 5.5
Parts and Japanese Pharmacopoeia absorbent cotton 7 parts were mixed to obtain a mixture (Y). Next, using a paper pattern in which a central portion of the corrugated cardboard paper (ellipse shape centering on the intersection of the diagonal lines of the rectangle, long axis 40 cm x short axis 10 cm) cut into a size of 15 cm × 45 cm in advance was cut with a cutter, The finely mixed mixture (Y) was evenly stacked on the center of the ellipse, and then the pattern was gently removed. Subsequently, the mixture (X) was formed in a portion other than the elliptical central portion and had an overall size of 15 cm × 4.
Fibers were uniformly deposited in a 5 cm area. And a heater plate press machine (model number N4008- manufactured by NPA System Co., Ltd.)
00) at 50 ° C. and 8 kg / cm ² of 30
By pressing for 2 seconds, an absorber layer (B) having an absorber layer (B) at the center of the elliptical shape and an absorber layer (A) at a portion other than the center of the ellipse was obtained.

<Preparation Example 2> An absorber layer (C-2) was obtained in the same manner as in Preparation Example 1 except that the water absorbent resin (A-4) was used instead of the water absorbent resin (A-2).

<Preparation Example 3> Other than using the water absorbent resin (A-2) instead of the water absorbent resin (A-1) and the water absorbent resin (A-3) instead of the water absorbent resin (A-2). In the same manner as in Preparation Example 1, an absorber layer (C-3) was obtained.

<Preparation Example 4> Other than using the water absorbent resin (A-4) in place of the water absorbent resin (A-1) and the water absorbent resin (A-3) in place of the water absorbent resin (A-2). In the same manner as in Preparation Example 1, an absorber layer (C-4) was obtained.

<Preparation Example 5> 10 parts of water-absorbent resin (A-3) and 15 parts of Japanese Pharmacopoeia absorbent cotton (Kawamoto Sangyo Co., Ltd.) were mixed by hand about 500 times with mixing until the appearance was uniform. A refined mixture (Z) was obtained. 15 pieces of defibrated mixture (Z)
cm * 45 cm and then uniformly sprinkled, then a heater plate press made by NPA System Co., Ltd. (Model N400
8-00) was pressed at 50 ° C. at 8 Kg / cm ² for 30 seconds to obtain an absorber layer (A-1).

<Preparation Example 6> An absorber layer (B-1) was obtained in the same manner as in Preparation Example 5 except that the water absorbent resin (A-3) was used in place of the water absorbent resin (A-3).

<Preparation Example 7> An absorber layer (A-2) was obtained in the same manner as in Preparation Example 1 except that the water absorbent resin (A-3) was used instead of the water absorbent resin (A-2).

<Preparation Example 8> Except that the water absorbent resin (a-2) is used instead of the water absorbent resin (a-1) and the water absorbent resin (a-4) is used instead of the water absorbent resin (a-2). In the same manner as in Preparation Example 1, an absorber layer (B-2) was obtained.

Absorber layers (C-1) to (C of Preparation Examples 1 to 8)
-4), (A-1) to (A-2) and (B-1) to (B
-2) and using the following absorbent articles (1) to
(4) and comparative absorbent articles (1) to (4) were produced. <Example 1> 40 μm thick as a liquid-impermeable back sheet
m absorber film (C-1) is arranged in the central part on a polypropylene film (20 cm x 50 cm), and a 100 μm thick polyethylene terephthalate nonwoven fabric (20 cm x 50 cm) as a liquid-permeable surface sheet on the absorber layer (C-1). After arranging, by using a heater plate press machine (model number N4008-00) manufactured by NPA System Co., Ltd., at 50 ° C., and pressing at 8 Kg / cm ² for 30 seconds,
An absorbent article (1) was obtained.

Example 2 An absorbent article (2) was obtained in the same manner as in Example 1 except that the absorber layer (C-1) was changed to the absorber layer (C-2).

<Example 3> An absorbent article (3) was obtained in the same manner as in Example 1 except that the absorber layer (C-1) was changed to the absorber layer (C-3).

Example 4 An absorbent article (4) was obtained in the same manner as in Example 1 except that the absorber layer (C-1) was changed to the absorber layer (C-4).

Comparative Example 1 A comparative absorbent article (1) was obtained in the same manner as in Example 1 except that the absorbent layer (C-1) was changed to the absorbent layer (A-1).

Comparative Example 2 A comparative absorbent article (2) was obtained in the same manner as in Example 1 except that the absorbent layer (C-1) was changed to the absorbent layer (B-1).

Comparative Example 3 A comparative absorbent article (3) was obtained in the same manner as in Example 1 except that the absorbent layer (C-1) was changed to the absorbent layer (A-2).

<Comparative Example 4> A comparative absorbent article (4) was obtained in the same manner as in Example 1 except that the absorbent layer (C-1) was changed to the absorbent layer (B-2).

With respect to the absorbent articles 1 to 4 of the present invention and the comparative absorbent articles 1 to 4, the resistance to leakage was evaluated, and the results are shown in Table 1. The size of the absorber cut out from the absorbent article was SH = 17 cm and LH = 47 cm.

[0127]

[Table 1]

[0128]

The absorbent article of the present invention has a very high anti-leak effect. Therefore, particularly when used as a hygiene product, even if the absorbent article is made thin, the problem that excreted urine leaks from the lateral portion of the hygiene product and stains the clothes is extremely small. Therefore, the absorbent article of the present invention,
Ideal for disposable disposable diapers, various pads and sanitary napkins.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an outline of a state in which a filtration cylindrical tube of a gel liquid permeability measuring apparatus is disassembled into parts.

FIG. 2 is a cross-sectional view showing an outline of a load of a device for measuring gel liquid permeability.

[Explanation of symbols]

1 cylinder 2 wire mesh 3 packing 4 Joint for fixing thin tube Capillary tube with 5 cocks 6 Wire mesh load 7 lid 8 weights

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4C003 AA22 AA23                 4C098 AA09 CE06 DD04 DD05 DD06                       DD10 DD14 DD16 DD24 DD25                       DD26 DD27 DD28

Claims (7)

[Claims] 1. A gel flow rate (ml / min) of 0.0
An absorbent article comprising a water-absorbent resin (a) of 1 or more and 3 or less and a water-absorbent resin (a) of 5 or more and 200 or less in gel flow rate (ml / min). It should be noted that the gel flow rate was determined by using a vertically standing cylinder (inner diameter 25.4).
mm) with a wire mesh (opening 150 μm) and a cock (inner diameter 2 mm) at the lower end of the opening (inner diameter 4 mm, length 8 c)
m) and 0.200 g of a measurement sample adjusted to a particle size of 850 to 150 μm were put into the filtration cylinder tube with the cock closed, 50 ml of physiological saline was poured, and the mixture was allowed to stand for 30 minutes after starting pouring. After that, wire mesh (opening 150
μm, diameter 25 mm) with a load (21.2 g) inserted into the filtration cylinder so that the wire mesh and the measurement sample are in contact with each other, and 1 minute later, a weight (77.0 g) is placed on the load with the wire mesh,
After still standing for 1 minute, the cock is opened and the time (T1) (seconds) until the liquid level of the physiological saline reaches the scale line of 40 ml to the scale line of 20 ml is measured and calculated from the following formula {( T0) is the time when there is no measurement sample}. [Equation 1] 2. An absorber layer (A) containing a water absorbent resin (A) and an absorber layer (B) containing a water absorbent resin (A), or (A) and (A). ) Containing an absorber layer (C) and optionally (A) and / or (B)
The absorbent article according to claim 1, comprising: 3. The content of the absorbent resin (a) existing in the outermost portion (a) is such that the absorbent layer (A) and the absorbent layer (C) are
7 based on the total weight of the absorbent resin (a) contained in
The absorbent article according to claim 2, which is 0% by weight or more and 100% by weight or less. The outermost portion (a) is a maximum projection surface having the maximum area of the projection surfaces on which the absorber layer is arbitrarily projected, and includes 50% of the total area of the maximum projection surface, and the contour of the maximum projection surface. Is a portion obtained by cutting a portion of the absorber layer corresponding to a region having an evenly spaced width with a plane perpendicular to the maximum projection plane. 4. The content of the absorber layer (A) is 5% by weight or more and 50% by weight or less based on the total weight of the absorber layer (A), the absorber layer (B) and the absorber layer (C). The absorbent article according to claim 2 or 3, wherein the content of the absorber layer (B) is 50% by weight or more and 95% by weight or less, and the content of the absorber layer (C) is 30% by weight or less. . 5. An absorber layer (A), an absorber layer (B) and an absorber layer (C) based on the area of the largest projection plane having the largest area among the projection planes on which the absorber layer is arbitrarily projected. The total content (g / m ² ) of the water-absorbent resin (a) and the water-absorbent resin (a) present in the composition is 50 or more and 250 or less, and based on the total content of (a) and (a) The absorbent article according to any one of claims 2 to 4, wherein the content (% by weight) of (a) is 10 or more and 95 or less. 6. The content of (A) and (A) based on the total content of the water-absorbent resin (A), the water-absorbent resin (A) and the fibrous material (% by weight) ) Is 10 or more and 95 or less, The absorbent article according to any one of claims 1 to 5. 7. The absorbent article according to claim 1, wherein the absorbent article is a disposable diaper, and the water-absorbent article has a leak resistance (g) of 200 or more and 1,000 or less. In addition, the anti-leakage property is a plate obtained by cutting an absorber (a component part of a paper diaper consisting of a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber layer) from a paper diaper into a rectangle and inclining it at 45 degrees. The rectangular sheet has a short side (SH <cm>) with one end on the upper side and the other end on the lower side, and the long side of the absorber from the other end of the short side ( L
H <cm>) is filled with physiological saline at a rate of 400 g / min using a glass tube with an inner diameter of 1 cm to the inner part corresponding to 10% of H <cm>) and the center of the short side. ,
The time (e <second>) from the start of injecting physiological saline to the start of leakage of physiological saline from the other end of the short side is measured and calculated from the following equation. [Equation 2]