JPH10295726A - Disposable diaper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give no uncomfortable feeling due to urination and detect urination more adequately, by providing a disposable diaper with a leakage sensor for detecting urination by a change in impedance between electrodes. SOLUTION: The disposable diaper comprises an impermeable sheet, a water absorbing layer and a permeable sheet disposed successively at least from a lining and by forming strap-shaped water-absorptive material layers 10, 11 in the impermeable sheet 1 so as to bridge between a pair of electrodes 2, 3 of a leakage detecting part composed of at least the pair of the electrodes 2, 3, a change in impedance between both electrodes due to urination is made more evident.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disposable diaper having a wetting detection sensor, and more particularly, to a disposable diaper having a sensor structure capable of reliably detecting wetting.

[0002]

2. Description of the Related Art There are two types of disposable diapers, a one-piece type in which a waterproof cover and a water-absorbing layer are integrated, and a two-piece type, in which a water-absorbing layer and a waterproof cover are separated. . Non-woven fabric, pulp,
A material such as an absorbent polymer is used, and can absorb and hold urine output several times. These disposable diapers are widely used by those who cannot handle urination and defecation by themselves, from infants to the elderly and the sick, who have difficulty in undulating. Usually, diapers are used in such a style that mothers and caregivers regularly check the diapers and replace them if they are wet. Therefore, if urination or defecation is performed before the replacement time, the patient is left unpleasant until the next replacement, which is not good for the environment and the health of the care receiver. Especially in hospitals and nursing homes where a large number of patients who need diapers are nurtured by a small number of nurses and caregivers for 24 hours, diapers should be changed regularly and changed even if they are not wet. And unnecessary labor of exchanging diapers for those who do not need to be exchanged,
In addition, extra costs are incurred economically. For this reason, many diapers having a wetness detection sensor have been devised, which detect urination or defecation and notify a caregiver of the fact.

The detection methods are roughly classified into two types: one in which the sensor is disposable, and the other in which the sensor can be washed and used many times. Many types that can be washed and used many times have a humidity sensor that is waterproof and covered with a flexible plastic film, so the detection part is used together when setting the diaper Things. In addition, it is roughly divided into the disposable sensor 2
There are different types, one is a disposable diaper and sensor integrated, the other is a separate sensor and diaper, and the sensor itself is disposable. Among these devices, the representative type of the former type will be described in more detail. Real fair 3-15063
FIG. 7 shows a plan view of a disposable diaper in which a wetting detection sensor is disposed integrally with the disposable diaper.

A water-impermeable sheet 25, a water-absorbing layer 26, and a water-permeable sheet 27 are sequentially laminated, and a metal foil 28 made of aluminum or the like is provided between the water-impermeable sheet 25 and the water-absorbing layer 26 in parallel. , 29 are laminated. The disposable diaper according to the present disclosure is a method of measuring a decrease in conductivity due to urine between two conductors 28 and 29, that is, a change in resistance value at the lead terminals 30 and 31. The sensor unit is also discarded together with the diaper. Type. Reference numerals 32 and 33 denote tapes with an adhesive for setting the diaper to the user.
As for the latter type in which only the sensor portion is separately disposable, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 7-239990. The plan view is shown in FIG.

In FIG. 8, a pair of electrodes 35, 3 formed by printing a conductive paint such as carbon paste on the surface of a film 34 such as paper or polyethylene terephthalate by a printing method.
6 is formed and connected to an external detection device at one end 37, 38. An adhesive material is applied and formed on the back surface of the film 34 so that the film 34 can be attached to the diaper surface and used. In addition, the detection methods of the devices that have been devised so far use a humidity sensor made of a material that is sensitive to humidity, use a change in the resistance value between two conductive electrodes, and use an electrically insulating material in a dry state. Two electrodes are formed at positions facing each other via the electrically insulating sheet via the sheet, and a method using a capacitance value change that detects a change in the dielectric constant of the sheet due to wetting, or a diaper sheet surface There is a method of forming a heterogeneous metal foil at regular intervals and excreting urine, which is an electrolyte, generates an electromotive force between the different metals, and measures the electromotive force.

[0006]

However, conventional disposable diapers with a wetting detection sensor have several problems. Japanese Patent Application Laid-Open No. 7-239990 discloses a type in which a wetness detection sensor is separate from a diaper,
When a humidity sensor protected by a plastic film or the like is used by inserting it into a diaper, the contaminated diaper can be washed and used multiple times, which is advantageous in terms of cost. The sensor must be set to the optimal position for the diaper. Especially when hospitals and nursing homes need to take care of many cared people with a small number of people, it takes time to set and
If the sensor unit is set at a position deviated from the optimal position, the sensor may not operate even when urinating, which is a problem.

[0007] The configuration of the disposable sensor disclosed in Japanese Patent Application Laid-Open No. 7-239990 is such that a conductor for detecting wetting is provided on the surface of paper or plastic film. There is a problem in that the wet state continues, and the wet surface is constantly in contact with the skin of the diaper user, so that discomfort is large. Also,
The one disclosed in Japanese Utility Model Publication No. 3-15063, in which the diaper and the wetting detection sensor are both disposable and integrated, has no problem in detecting urine because a conductor electrode is formed on the surface of the water-impermeable sheet. Although it seems possible, there is a problem with detecting bowel movements. Since the detection electrode is formed between the water-impermeable sheet and the water-absorbing layer, the structure cannot be directly contacted with the stool, and it is considered that the detection cannot actually be performed. To solve this problem, it is possible to form the stool detection sensor on the surface of the water-permeable sheet that touches the user's skin.However, if you try to provide a low-cost disposable diaper equipped with urination and defecation sensors For example, forming the defecation and urination sensors on one sheet surface simplifies the manufacturing process and is advantageous in cost reduction. In order to detect defecation, it is necessary to form a sensitive part in a part close to the user's skin. Therefore, forming a urine detection sensor on the same sheet surface as the defecation detection sensor can contribute to a reduction in manufacturing cost.

Currently used water-permeable sheets (sheets that come into contact with the skin of the user) of disposable diapers (without a wetting detection sensor) are made of a material that does not absorb water at all, such as polypropylene fiber. Non-woven fabric is used, and the surface of which is treated hydrophilically is placed on the water-absorbing layer, or the water-absorbing layer is made of a special absorbent polymer, absorbs urine, becomes a gel-like semi-cured state, and becomes more wet Those that reduce discomfort are commercially available. When urine is discharged into such a disposable diaper, the urine passes through the water-permeable sheet in a short time and is absorbed and held in the water absorbing layer.

Accordingly, the water-permeable sheet is brought into a state close to a dry state in a short time. This is because the wet diaper is in contact with the skin, which causes discomfort to the user, and the water-permeable sheet is selected so that the material is dried quickly. When a wetting detection sensor is formed on a water-permeable sheet having such characteristics, particularly when a change in resistance or capacitance between conductors is used as a detecting means, the water-permeable sheet can be urgently discharged even after urination. The urine in the lower part migrates to the lower water-absorbing layer and becomes in a dry state, so that a stable measured value cannot be obtained, and there is a problem that the measured value is such that the urine does not urinate over time after urination.

FIG. 9 is a perspective view of the structure of a disposable diaper with a wetting detection sensor as disclosed in Japanese Patent Application No. 8-313252, which uses a change in resistance value due to wetting as detecting means. The structure is such that the water impermeable sheet 40, the water absorbing layer 3
9 and the water-permeable sheet 1 and are integrated in the above-described order. The water impermeable sheet 40 is an outer cover of a diaper, and its material is mainly a polyethylene film or the like. The water-absorbing layer 39 is a layer that absorbs urine, and is made of pulp, paper, nonwoven fabric, or a polymer-absorbing polymer that absorbs water and gels so that the user does not feel much discomfort. The water-permeable sheet 1 is a portion that comes into contact with the skin of the diaper user, and a sheet in which hydrophilic treatment is applied to the surface of a nonwoven fabric sheet made of a polypropylene fiber that hardly absorbs water is often used. The effect is that the urine is immediately transferred to the lower water-absorbing layer 39 as soon as the urine is excreted because the sheet 1 does not absorb urine, and the water-permeable sheet 1 is dried in a short time, so that the diaper user may not be wet. It is intended to minimize pleasure.

On the surface of the water-permeable sheet 1, for example, a conductor 2 obtained by printing and curing a paste obtained by blending a carbon powder or a silver powder with a thermosetting resin by a screen printing method or the like,
3, 4, 5, 6, and 7 are formed, and terminal portions 8-1 to 8-6 are formed at the left end of each conductor. In the detection mechanism, for example, when urine is discharged, urine penetrates between the conductors 2 and 3 formed in the vicinity of the urine, and the resistance value between the conductors 2-3 decreases. The value is measured by a resistance value change measuring device connected to the terminal portions 8-1 and 8-2 to know that urination has occurred. Further, the bowel movement is such that the bowel contacts the comb-shaped electrode 9 formed near the bowel movement, and reduces the resistance value between the electrodes to reduce the resistance value between the conductors 6 and 7 connected to the comb-shaped body 9 and to the terminal part 8 connected thereto.
-3, 8-4 resistance change is detected by an external measuring device,
Know your bowel movements.

The conventional urine detection sensor of a disposable diaper having this structure is formed on the surface of the water-permeable sheet 1, so that when urinating, the resistance between the conductors 2-3 decreases and urine can be detected. After a lapse of time after urination, the urine is absorbed and transferred to the lower water-absorbing layer 39 in contact with the urine, and the space between the conductors 2 and 3 is in a dry state. In one example of our experiment, the resistance value began to rise within 1 minute after urination, the resistance value approached the initial state where urine was not discharged after 10 to 20 minutes, and urination could not be detected after 30 minutes or more . The present invention is capable of detecting urination irrespective of the lapse of time after urination, even if the material configuration and sensor configuration of the conventional disposable diaper follow the material as it is,
In other words, the invention provides a structure in which the resistance value does not increase with the lapse of time.

[0013]

SUMMARY OF THE INVENTION In order to solve such a conventional problem, a disposable diaper according to the present invention comprises a water-impermeable sheet, a water-absorbing layer, and a water-permeable sheet. A detection unit is formed, and a water-absorbing material layer having the same or a larger area as the wetting detection unit is formed on the water-permeable sheet of the wetting detection unit formed on the water-permeable sheet. According to this configuration, after the urine is discharged, the wet detection portion maintains the wet state due to the water absorbing material layer, and a stable measured value can be obtained regardless of the urination elapsed time. In addition, a disposable diaper that can accurately detect both defecation can be provided at low cost.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION
Water-impermeable sheet arranged at least in order from the back,
A disposable diaper comprising a water-absorbing layer and a water-permeable sheet, and detecting a change in impedance between the pair of electrodes of a wetting detection unit including at least a pair of electrodes formed on the water-permeable sheet to detect wetting. , A band-shaped water-absorbing material layer is formed on the water-permeable sheet so as to bridge between the pair of electrodes. The water-absorbing material layer is formed on the back or front surface of the water-permeable sheet or inside the water-permeable sheet. ADVANTAGE OF THE INVENTION According to the form of this invention, the sheet | seat with a wetting detection sensor which can provide the dry state to the user's skin which comprised the wetting detection part in the nonwoven fabrics, such as a polypropylene which hardly absorbs water, can be provided. That is, since the urinated urine is held in a necessary minimum amount in the small-sized water-absorbing material layer on the water-permeable sheet surface, the urination state can be detected irrespective of the elapsed time after urination. Furthermore, the present invention can provide a diaper with a wetting detection that hardly gives a diaper user an unpleasant feeling due to the wetting of the water absorbing material layer because the water absorbing material layer of a small size is formed only in a necessary portion.

Further, in the invention according to a second aspect, the water-absorbing material layer is formed such that a paste-like material containing a water-absorbing material is at least partially penetrated into the water-permeable sheet. It is formed by coating on a sheet. According to the structure of the present invention, since the water-absorbent material is impregnated in the water-permeable sheet, the water-absorbent material is strongly adhered to the sheet, and the water-absorbent material layer is subjected to peeling force due to kinking or the like when using a diaper. However, it does not peel off from the sheet.
In addition, if the water-absorbing material layer is almost completely impregnated in the water-permeable sheet, it is possible to provide a wetting detection sensor with less irregularities.

According to a third aspect of the present invention, there is provided a water-impermeable sheet, a water-absorbing layer, and a water-permeable sheet arranged at least in order from the back, and at least one pair of electrodes formed on the water-permeable sheet. In a disposable diaper that detects a change in impedance between the pair of electrodes of the wetting detecting unit and detects wetting, the water-permeable sheet includes two water-permeable sheets that are in close contact with each other. Each of the electrodes has a structure in which a water absorbing material layer is formed between the two water-permeable sheets so as to be located between the pair of electrodes. doing. The present invention relates to a wetting sensor using a change in impedance or dielectric constant between two electrodes due to wetting as a means for detecting wetting, and comprising the wetting sensor using a nonwoven fabric sheet made of a polymer having no water absorption. Also, since a water-absorbing material layer is formed on the sensor portion, urinated urine does not move to the lower water-absorbing layer, and stays in the water-absorbing material layer between the electrodes, thereby maintaining a wet state with urine and stable. Wetness detection is now possible.

(Embodiment) The first aspect of the present invention will be described below.
A disposable diaper with a wetting detection sensor according to the present invention described in claims 2 and 3 will be described with reference to FIGS. 1, 2, 3, 4, 5, and 6.

FIGS. 1, 2 and 3 are block diagrams showing a first embodiment of the present invention. FIG. 1 is a plan view of a water-permeable sheet portion 1 in the material configuration of the conventional disposable diaper described with reference to FIG. 9, and FIGS. 2 and 3 are cross-sectional views taken along the line AA in FIG. Each shows an enlarged view. The configuration of the disposable diaper is the same as that shown in FIG.
A water-absorbing layer 39 and a water-impermeable sheet 40 are laminated and integrated below the water-permeable sheet 1 in FIG. FIG.
In the surface of the water-permeable sheet 1 (the material, surface treatment and the like are the same as the above-mentioned conventional ones), a printing paste in which carbon powder, silver powder and the like are blended with a thermosetting resin is used. At least one pair or more of urine detection conductors 2 formed by pattern printing and curing by a screen printing method,
3, 4, 5, 6, and 7 are formed, and the other end is connected to a terminal 8-2, 8-
1, 8-5 and 8-6 are formed. In another part of the water-permeable sheet 1, a comb-shaped conductor 9 for detecting defecation is provided.
Is formed of the same material and method as the urine detection conductor,
The comb-shaped conductor 9 includes conductors 6 and 7 and terminal portions 8-3 and 8-4.
Are connected to each other. The conductor pair of the urine detection conductors 2 and 3 is formed at a position where it comes into contact with urine first when its distal end portion is urinated.
Of the diaper are located at different positions in the diaper. The purpose is to be able to detect the amount of urination to some extent. Further, water-absorbing material layers 10 and 11 are formed in the end portions of the urine detection conductors 2, 3, 4 and 5 in a band shape bridging the conductors 2, 3, 4 and 5.

FIGS. 2 and 3 are enlarged cross-sectional views taken along the line AA of FIG. In the embodiment of FIG. 2, the water-permeable sheet 1
The conductors 2 and 3 are formed on the surface of the diaper that contacts the skin of the user. As shown in FIG. 2 or FIG. 3, since the water-permeable sheet 1 is a non-woven fabric of fine fibers, when the conductors 2 and 3 are formed by a printing method, the paste partially penetrates into the water-permeable sheet 1. It has a hardened shape. The conductor 2,
The surface of the water-permeable sheet 1 opposite to the surface 3 is provided with a water-absorbing material layer 10.
The water-absorbing material layer 10 is formed in a band shape so as to connect the conductors 2 and 3. Various forming methods can be applied. For example, there is a method in which a material having water absorbency is formed into a paste, printed by a screen printing method, dried, cured, and formed. Examples of the material include various thermoplastic resins, thermosetting resins, synthetic rubbers, and starch. ,
A paste obtained by kneading a water-absorbing material such as pulp fiber, inorganic oxide, or water-absorbing polymer alone or in combination with natural glue such as glue or casein is used.

Further, as another method, a method of bonding a water-absorbent fabric such as paper or cotton having a large water absorption to the water-permeable sheet 1, or a method of applying a hydrophilic material itself is used. Applicable. According to the structure of the present embodiment, the discharged urine is trapped in the water-absorbing material layer 10, and the trapped urine moisture stays in the water-absorbing material layer 10, and as a result, the conductor 2-3 or 4-5 passes between the conductors 2-3 or 4-5. Since the state of bridging with urine is maintained for a long time, urination can be detected for a long time. The water absorbing material layer 10 for urine / moisture trap is 10 μm
Conductors 2 and 3 in the thin film state before and after
Alternatively, since it is only necessary to bridge between 4 and 5, it may be formed with a minimum size, and the water-absorbing material layer 10 always keeps wet with urine after urinating, but the thickness is small and small. Due to the area, the diaper user hardly feels wet or discomfort. In the present description, the conductors 2 to 5 are described as being formed on the side that comes into contact with the skin of the diaper user. However, it goes without saying that there is no problem if the conductors 2 to 5 are formed on the opposite side of the water-permeable sheet 1.

FIG. 3 shows another embodiment of the present invention, and is an enlarged cross-sectional view taken along the line AA of FIG. The difference from FIG. 2 is that the water-absorbing material layer 10 is formed on the same surface as the conductors 2 and 3, and the wetting detection sensor can be constituted by only one surface of the water-permeable sheet 1.
There is an advantage that the manufacturing cost is low. There is no difference in the wetting detection characteristic from that of FIG.

Next, another embodiment of the present invention will be described with reference to FIGS. 4 and 5 are enlarged cross-sectional views taken along the line AA of FIG. In FIG. 4, conductor pairs 2 and 3 are formed on the surface of a water-permeable sheet 1.
0 is formed. The water-absorbing material layer 10 is formed so as to penetrate the water-permeable sheet 1, and the water-absorbing material layer 10 is formed so as to cover between the conductor pairs 2-3. According to this configuration, the water-absorbing material layer 10 is
Because it is impregnated inside, its holding strength is large,
Since the water absorbing material layer is hard to fall off, the water absorbing material layer is hardly peeled off due to kinks of the diaper at the time of using the diaper, and the water absorbing material layer 10 which is hard to fall off can be formed, and stable wetting detection can be performed. The formation method can be made by forming the conductors 2 and 3 and then dropping and drying the solution containing the water absorbing material 10.

FIG. 5 is basically the same as that of FIG. 4, except that the water absorbing material layer 10 is formed only between the conductor pairs 2-3. The advantage is that the area of the water-absorbing material layer 10 can be formed to a minimum, so that the area of the wet portion that touches the skin of the diaper user can be reduced, and a product that minimizes wet discomfort can be provided.

Another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a perspective view showing the configuration of only the water-permeable sheet portion of a normal disposable diaper in which a water-impermeable sheet, a water-absorbing layer, and a water-permeable sheet are laminated and integrated in this order. This configuration shows an example in which a change in impedance and a change in dielectric constant due to wetting, that is, an example in which a resistance change type or capacitance change type wetting sensor is configured in a water permeable sheet portion. The structure of the wetting detection sensor unit of this configuration is such that at least one or more measurement electrodes 17 and 18 are formed on one surface of the water-permeable sheet 12 that has been subjected to the hydrophilic treatment using a thermosetting conductive paste. Are formed at certain intervals, and conductors 15 and 16 are connected to the electrodes 17 and 18, respectively, and terminal electrodes 8-1 for connection to a measuring device are provided at ends of the conductors 15 and 16. , And 8-2 are connected to each other. Further, in the same manner as described above, the stool detection comb-shaped electrode 9, the conductors 6, 7 connected thereto, and the terminal electrodes 8-3, 8
-4 are formed. Another water permeable sheet 1
3. On one surface, electrodes 21 and 22 having substantially the same shape and the same area as the detection electrodes 17 and 18 are formed at positions opposed to the detection electrodes 17 and 18, respectively. , 20 and terminals 8-7, 8-8 are connected.

Further, on one surface of another water-permeable sheet 14, water-absorbing material layers 23 and 24 are formed. The water-absorbing material layers 23 and 24 are formed at positions corresponding to the measurement electrodes 17 and 18, and have shapes and sizes similar to the measurement electrodes 17 and 18, and have the same or larger sizes. It is formed as follows. These three water-permeable sheets 12, 13 and 14 are laminated, adhered and integrated so as to maintain the above-mentioned positional relationship. According to this configuration, when urine is discharged, the water-absorbing material layers 23 and 24 become wet, the impedance or the dielectric constant changes, and it can be detected that urination has occurred. In addition, the water-absorbing material layers 23 and 24 stably retain moisture. Wetting can be detected. Water absorbing material layer 23,
Reference numeral 24 is not limited to that of the present embodiment as long as it has the ability to retain moisture. For example, water permeable sheet 1
4, the same characteristics can be obtained as long as the sheet has a water-retaining ability, such as paper or cloth of the same size as the water-absorbing material layers 23 and 24. The same effect can also be obtained by coating a natural or synthetic material having water absorbency and water retention or a blend of a natural or synthetic adhesive with a water absorbent material in the form of a film.

In the above embodiment, the conductor formation method by screen printing using various thick film materials as the conductor material has been described. However, a method in which a conductive foil such as an aluminum foil is joined, or a vapor deposition or sputtering method or the like is used. Various conductor materials, such as those formed with a conductor film, can be applied without significant difference. Further, as the wetting detection method, the embodiment using the resistance value change and the capacitance value change has been described, but the present invention is not limited to the wetting detection method, so there is no problem with other wetting detection methods. It goes without saying that it can be applied. Furthermore, since the main point of the present invention is that the sensing portion has a water absorbing material layer, the water absorbing material is not limited, and has the functions shown in this embodiment in addition to the materials shown in the above-described embodiment. There is no problem with any material.

[0027]

As described above, when the disposable diaper of the present invention is used, the resistance value of the non-woven sheet made of synthetic fiber having almost no water absorption to reduce the discomfort of the diaper user, that is, to reduce wet discomfort due to urination. By forming a thin layer of water-absorbing material with water retention on the wetting detection unit, which has a wetting sensor that detects changes and changes in volume, etc. Is inaccurate, but a structure that maintains stable electrical displacement can be provided, so that a wet state can be accurately detected regardless of the elapsed time after urination. In addition, even if there is a difference in the wetting detection means, this configuration is a method that can be applied in a wide range of applications, and can be applied without major restrictions. Further, since the structure only forms the water-absorbing material layer, the influence on the manufacturing cost is small, and the increase in cost is negligible during mass production by an automated device.

[Brief description of the drawings]

FIG. 1 is a plan view of a disposable diaper according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along a line AA in FIG. 1;

FIG. 3 is an enlarged cross-sectional view of another configuration of the AA section in FIG. 1;

FIG. 4 is an enlarged cross-sectional view of still another configuration taken along the line AA in FIG. 1;

FIG. 5 is an enlarged cross-sectional view of still another configuration of the section AA in FIG. 1;

FIG. 6 is an exploded perspective view of a disposable diaper according to another embodiment of the present invention.

FIG. 7 is a plan view of a conventional disposable diaper with a wetting sensor.

FIG. 8 is a plan view of a wetness sensor portion, which is separate from the conventional diaper portion.

FIG. 9 is a perspective view of a conventional sensor-integrated disposable diaper configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water-permeable sheet 2, 3, 4, 5, 6, 7 Conductor 8-1 to 8-8 Terminal part 9 Comb-shaped conductor 10 Water-absorbing material layer 25 Water-impermeable sheet 26 Water-absorbing layer

Claims (3)

[Claims] 1. A water-impermeable sheet, a water-absorbing layer, and a water-permeable sheet, which are arranged at least in order from the back surface, and wherein said pair of wetting detecting units each include at least a pair of electrodes formed on said water-permeable sheet. In a disposable diaper that detects a change in impedance between the electrodes and detects wetting, a band-shaped water-absorbing material layer is formed on the water-permeable sheet so as to bridge between the pair of electrodes. Disposable diapers. 2. The water-absorbing material layer is formed by applying a paste-like material containing a water-absorbing material on the water-permeable sheet so that at least a part thereof penetrates the water-permeable sheet. The disposable diaper according to claim 1, wherein the diaper is made. 3. A water-impermeable sheet, a water-absorbing layer, and a water-permeable sheet, which are arranged at least in order from the back surface, and wherein said pair of wetting detecting units each include at least a pair of electrodes formed on said water-permeable sheet. In a disposable diaper that detects a change in impedance between the electrodes and detects wetting, the water-permeable sheet is composed of two water-permeable sheets adhered to each other, and each electrode of the pair of electrodes is A disposable diaper which is formed so as to face each of the water-permeable sheets, and wherein a water-absorbing material layer is formed between the water-permeable sheets so as to be located between the pair of electrodes.