JP2022100266A - Absorbent article, manufacturing method for the same, and water detection system comprising the same - Google Patents

Abstract

To provide an absorbent article that can appropriately detect water generation with a simple configuration and provides little discomfort for a wearer.SOLUTION: An absorbent article includes at least a top sheet, an absorber, a back sheet, and a sensor having a water detection unit. The absorber is composed of a core for absorbing water and a wrap sheet wrapping the core. The sensor is disposed between the wrap sheet of the absorber and the back sheet. The sensor's thickness is equal to or smaller than 1 mm.SELECTED DRAWING: Figure 1

Description

The present invention relates to an absorbent article, a method for producing the same, and a moisture detection system including the same.

Conventionally, a system using RFID (Radio Frequency Identification) is known as a technique for detecting the presence of water in an absorbent article. In particular, as a nursing care application, a technique of embedding a wireless communication device such as an IC tag in a diaper is known in order to detect water generated due to urination or the like of a care recipient.

For example, Non-Patent Document 1 discloses a technique in which a reading device transmits a radio wave signal having a frequency of 950 MHz (UHF band) to an IC tag and detects moisture using the reflected signal. In this technique, the generation of water is detected by utilizing the fact that the antenna gets wet and the reflectance coefficient changes.

Further, Patent Document 1 discloses a technique of detecting the presence or absence of moisture in response to fluctuations in the voltage value of the wetness detection terminal by providing an IC tag provided with a wett detection terminal on the diaper. In this technique, when the wetness detection terminal detects wetness, the IC tag emits a signal different from that in the dry state, or does not transmit a signal. Therefore, the reading device communicating with the IC tag determines the type of signal to be received or The wet state of the IC tag is detected according to the presence or absence of a signal.

Further, in Patent Document 2, in a diaper that detects urination by an attached sensor device, a guide unit for attaching the sensor device to the inseam of the diaper is provided in order to accurately detect urination while reducing the discomfort of the wearer. The structure is shown.

Japanese Unexamined Patent Publication No. 2006-349418 Japanese Unexamined Patent Publication No. 2019-130244

Hiromasa Nakajima, 3 outsiders, "Development of Urination Detection System Using RFID Technology", IEICE Journal B Vol.J96-B No.12 pp.1378-1385, December 1, 2013

However, in the technique described in Non-Patent Document 1, radio waves are absorbed with the generation of moisture, the impedance of the antenna changes significantly, the reception sensitivity of the IC tag is significantly lowered, and communication with the reading device is possible. Therefore, there is a problem that the reading device side cannot determine the case where the IC tag has failed.

Further, in the technique described in Patent Document 1, the state or function of the IC chip is changed according to the detection result of the wetness detection terminal, but a relatively expensive IC chip is required and the IC chip is used. There are many cost issues such as the need for high-precision mounting technology. Further, it is necessary to mount an IC chip, and there is a problem that the mechanical strength as an IC tag is weak.

Further, in the technique described in Patent Document 2, although the sensor device is arranged at a predetermined position by providing the guide portion, the thickness dimension of the sensor device is usually 1 to 30 mm, preferably 1 to 20 mm, more preferably. Was 1 to 15 mm, and the discomfort of the wearer was not sufficiently reduced.

The present invention has been made in view of the above, and an object of the present invention is to provide an absorbent article capable of accurately detecting the generation of moisture by a simple configuration and having less discomfort to the wearer.

In order to solve the above-mentioned problems and achieve the object, the absorbent article according to the present invention includes at least a top sheet, an absorber, a back sheet, and a sensor having a moisture detection unit. The absorber is composed of a core that absorbs water and a wrap sheet that covers the core, and the sensor is arranged between the wrap sheet and the back sheet of the absorber. The sensor is characterized in that the thickness is 1 mm or less.

Further, in the absorbent article according to the present invention, in the above invention, the moisture detection unit includes a conductor, and at least a part of the conductor comes into contact with the wrap sheet.

Further, in the above-mentioned invention, the absorbent article according to the present invention has a moisture detection portion having a thickness of 200 μm or less.

Further, in the absorbent article according to the present invention, in the above invention, the moisture detection unit includes a conductor, and the thickness of the conductor is 100 μm or less.

Further, in the above-mentioned invention, the absorbent article according to the present invention has a configuration in which the sensor does not come into contact with moisture except for the moisture detection unit.

Further, in the absorbent article according to the present invention, in the above invention, the sensor has an antenna portion.

Further, in the absorbent article according to the present invention, in the above invention, at least a part of the antenna portion is arranged at a portion where the top sheet and the back sheet face each other without sandwiching the absorber. ..

Further, in the absorbent article according to the present invention, in the above invention, the conductor of the moisture detection unit is composed of a pair or more of facing patterns containing at least a metal element and an organic component and not directly connected to each other.

Further, in the absorbent article according to the present invention, in the above invention, the resistance between one or more pairs of facing patterns that are not directly connected to each other in the moisture detection unit becomes 10 MΩ or less due to the contact with moisture.

Further, in the absorbent article according to the present invention, in the above invention, the sensor has a circuit unit.

Further, in the absorbent article according to the present invention, in the above invention, the sensor has a circuit portion and an antenna portion, and the conductive portion of the circuit portion and the antenna portion are non-contact.

Further, in the absorbent article according to the present invention, in the above invention, the moisture detection unit and the circuit unit are formed on the same surface on the same substrate.

Further, in the absorbent article according to the present invention, in the above invention, the circuit portion includes a thin film transistor containing carbon nanotubes.

Further, for the absorbent article according to the present invention, a method using a printing technique is used in any of the manufacturing processes.

Further, the moisture detection system according to the present invention includes an absorbent article according to any one of the above inventions, and a transmission / reception device provided with means for wirelessly communicating with the absorbent article.

According to the present invention, it is possible to provide an absorbent article that accurately detects the generation of moisture with a simple configuration and causes less discomfort to the wearer, and a moisture detection system using the absorbent article.

FIG. 1 is a plan view showing an absorbent article according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing an absorbent article according to the first embodiment of the present invention. FIG. 3 is a schematic view showing a moisture detection unit in a sensor in an absorbent article according to an embodiment of the present invention. FIG. 4 is a plan view showing an absorbent article according to a modification of the first embodiment of the present invention. FIG. 5 is a schematic view showing a modification 1 of the sensor in the absorbent article according to the embodiment of the present invention. FIG. 6 is a schematic diagram showing a modification 2 of the sensor according to the embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing a thin film transistor according to an embodiment of the present invention. FIG. 8 is a plan view showing the absorbent article according to the second modification of the first embodiment of the present invention. FIG. 9 is a schematic diagram showing a modification 3 of the sensor according to the embodiment of the present invention. FIG. 10 is a schematic diagram showing a modified example 4 of the sensor according to the embodiment of the present invention. FIG. 11 is a schematic diagram showing a moisture detection system according to an embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is a plan view schematically showing an absorbent article according to the first embodiment of the present invention, and FIG. 2 is a sectional view taken along the line XX'in FIG.

The absorbent article 10 according to the first embodiment has a top sheet 12 on the human body side and a back sheet 11 on the clothing side, and the absorbent body 20 is sandwiched between the top sheet 12 and the back sheet 11. The absorber 20 has a structure in which the core 21 is covered with the wrap sheet 22. Then, the sensor 30 is arranged between the back sheet 11 and the wrap sheet 22 that covers the absorber 20.

The absorbent article 10 is not particularly limited in its use and shape as long as it is an absorbent article designed and manufactured to absorb water discharged from the human body. Specific examples of the absorbent article 10 include disposable diapers, women's hygiene articles, incontinence products and the like. Further, the absorbent article 10 may be a pad that absorbs moisture. On the outside of such pads, pants-type diapers, pants that can be used repeatedly, and the like can be worn.

The material and composition of the top sheet 12 are not particularly limited as long as the moisture absorbed by the absorbent article 10 is permeable. Specific examples of the top sheet 12 include a liquid-permeable non-woven fabric, a three-dimensional perforated film, and a laminate thereof. Further, it may be a sheet obtained by combining various materials and having characteristics of partially different moisture permeability and surface condition. Since the top sheet 12 comes into direct contact with the human body, it is preferably a non-woven fabric or the like that is soft to the touch.

The material and composition of the back sheet 11 are not particularly limited as long as the back sheet 11 is configured so that the moisture absorbed by the absorbent article 10 does not permeate. Specific examples of the backsheet 11 include a non-woven fabric, a non-porous film, a porous film, and a laminate thereof. Further, a sheet obtained by combining various materials and having a partially moisture-impermeable sheet or a sheet having different surface states may be used. Although the backsheet 11 is configured so as not to allow moisture to permeate, it is desirable to have vapor permeability in order to improve the comfort of the wearer.

The material and composition of the core 21 are not particularly limited as long as it can absorb and retain water. Specific examples of the core 21 include an absorbent material composed of a cellulose fiber or a water-absorbent polymer.

The wrap sheet 22 is not particularly limited as long as it is a material that allows moisture to permeate and can hold the core 21. Specific examples of the wrap sheet 22 include paper, non-woven fabric, perforated film, and laminates and composites thereof.

The top sheet 12, the absorber 20, and the back sheet 11 are bonded to each other to form the absorbent article 10, but the bonding method, the material used for the bonding, the bonding area, the bonding range, and the like are not particularly limited, and the absorbent is absorbent. As long as the function as an article can be realized, a method and a configuration suitable for each can be appropriately adopted.

In the first embodiment, a three-dimensional gather may be provided near the end on the long side of the top sheet 12 to prevent moisture from leaking. Further, a tape for forming a pants-type diaper may be arranged near the short side end portion of the back sheet 11.

Further, in order to improve the wearing feeling of the wearer, the outer shape of the absorbent article 10 according to the first embodiment may be shaped to fit the human body.

Further, a non-woven fabric or the like for improving the feel may be arranged on the side of the back sheet 11 opposite to the top sheet 12 (the side in contact with clothing).

Although not shown, the sensor 30 has a structure in which a water detection unit is formed on a base material, and the water detection unit detects water discharged from the human body. Moisture discharged from the human body permeates the top sheet 12 and is absorbed by the absorber 20. By arranging the sensor 30 between the absorber 20 and the back sheet 11, the moisture absorbed by the absorber 20 touches the moisture detection unit of the sensor 30, so that the moisture discharged from the human body can be detected. .. Further, since the sensor 30 is arranged not on the top sheet 12 side of the absorber 20 but on the back seat 11 side, the discomfort felt by the wearer when wearing the absorbent article 10 is reduced, and the wearing feeling is not impaired.

As long as the water detection unit has a function of changing the state depending on the presence or absence of water and detecting the presence of water, the structure thereof, the material constituting the water detection unit, and the method of detecting the water content thereof are not particularly limited. As a specific configuration of the moisture detection unit, for example, (1) a pair of conductors having a certain space distance are arranged, and moisture adheres between the conductors to change the conductivity between the conductors to change the moisture content. (2) Multiple independent conductor patterns are arranged to detect changes in conductivity between conductors due to moisture adhering between the conductors. Independent conductor patterns are arranged, and the electrostatic capacitance between conductors changes due to moisture adhering to the moisture-impermeable insulating material arranged on the conductors. (4) Specific inductance A conductor pattern formed in a loop shape is included so that the conductor can be obtained, and the capacity value generated in the conductor changes due to the proximity of moisture to the conductor.

As long as the conductor has electrical conductivity, its material and composition are not particularly limited, but it is preferable that the conductor has low corrosiveness due to moisture and high conductivity. Specific examples of the conductor include, for example, an inorganic substance containing at least one element selected from the group consisting of gold, copper, silver, nickel, tin, bismuth, lead, zinc, palladium, platinum, aluminum, tungsten, molybdenum and carbon. Examples thereof include a mixture or laminate of the above-mentioned inorganic substance and organic substance, and an organic substance having conductivity.

FIG. 3 schematically shows a preferable shape of the moisture detection unit. The moisture detection unit 60 shown in the figure has a pattern of the first electrode 61 and the second electrode 62 on the base material 63 having electrical insulation. These electrodes may be connected to an external power source or the like by wiring (not shown).

In the water detection unit 60 shown in FIG. 3, the first electrode 61 and the second electrode 62 consist of a pair of facing patterns containing at least a metal element and an organic component and not directly connected to each other. Here, when water adheres to some part between the first electrode 61 and the second electrode 62, the first electrode 61 and the second electrode 62 are electrically connected via the water. , The resistance value between the first electrode 61 and the second electrode 62 is reduced. Moisture can be detected by reading the change in the resistance value.

The metal element preferably has high conductivity and excellent workability, and examples thereof include gold, silver, copper, nickel, tin, bismuth, lead, zinc, palladium, platinum, aluminum, tungsten, molybdenum, and carbon. Be done. These metals may be used alone or as an alloy. Further, the metal element is preferably contained in the form of particles, and may be a mixed particle of two or more kinds of metal particles.

The organic component is not particularly limited, but is not particularly limited, but is a monomer, an oligomer, a polymer, a photopolymerization initiator, a compound having a carboxyl group, a polymerization inhibitor, a plasticizer, a leveling agent, a surfactant, a silane coupling agent, and a defoaming agent. , Pigments and the like.

Since the first electrode 61 and the second electrode 62 contain a mixture or laminate of a metal element and an organic component, the electrode has excellent adhesion to the substrate and has good workability.

In FIG. 3, a comb-shaped pattern shape is shown as the shape of the facing pattern, but the shape of the facing pattern is not limited to this as long as the first electrode and the second electrode face each other.

The facing pattern formed by the first electrode 61 and the second electrode 62 determines the presence or absence of water by reducing the resistance value between the facing patterns due to the adhesion of water, but the presence or absence of water is determined by the circuit. From the viewpoint of ease of determination, it is preferable that the resistance value between the facing patterns becomes 10 MΩ or less due to contact with moisture.

The thickness of the sensor 30 is 1 mm or less. This is thin enough not to reduce the wearer's fit. The thickness of the sensor is preferably 10 μm or more, more preferably 50 μm or more as the lower limit from the viewpoint of achieving both ease of handling at the time of manufacturing the sensor 30 and improvement of the wearing feeling of the wearer of the absorbent article. The upper limit is preferably 500 μm or less.

By adjusting the water absorption characteristics of the absorber 20, it is possible to control the time until the water discharged from the human body reaches the sensor 30 and the amount of the water reaching the sensor 30. This makes it possible to realize an absorbent article in which the sensor 30 detects moisture at a desired time and moisture absorption amount. Examples of the method for adjusting the water absorption characteristics of the absorber 20 include a method of adjusting the thickness of the core 21 and a method of adjusting the material and composition of the core 21 (for example, a method of changing the composition of the core 21 in the thickness direction). Can be mentioned.

After the sensor 30 detects moisture, the method of transmitting the detection of moisture to the wearer or the worker who replaces the absorbent article is not particularly limited. Such methods include, for example, a method of changing the color of the sensor 30, a method of the sensor 30 emitting light and / or sound, a means such as a magnetic field, an electric field, a radio wave, an ultrasonic wave, etc. between the sensor 30 and the reading device. There is a method of communicating with.

The material and composition of the base material on which the moisture detection portion is formed in the sensor 30 is not particularly limited as long as it has electrical insulating properties and can be processed to a film thickness of 1 mm or less. The base material preferably has flexibility from the viewpoint of followability when the absorbent article is attached to the human body. Further, the base material is preferably one that does not allow moisture to permeate. Specific examples of the base material include PET (polyethylene terephthalate) film, PP (polypropylene) film, PVC (polyvinyl chloride) film, and laminates thereof.

The thickness of the base material is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of industrial processability. On the other hand, from the viewpoint of not deteriorating the wearing feeling of the absorbent article, it is preferably 1 mm or less, and more preferably 500 μm or less.

Further, in the water detection unit, for example, when water adheres to some part between the first electrode 61 and the second electrode 62, the first electrode 61 and the second electrode 62 pass through the water. Moisture is detected by being electrically connected to each other and reducing the resistance value between the first electrode 61 and the second electrode 62. In order to properly adhere moisture between the first electrode 61 and the second electrode 62, at least one of the first electrode 61 and the second electrode 62, preferably both, are in contact with the lap sheet. Configuration is desired. That is, it is preferable that at least a part of the conductor of the moisture detection unit comes into contact with the wrap sheet.

Further, in order to more appropriately attach moisture between the first electrode 61 and the second electrode 62, when the absorbent article is attached to the human body and the wrap sheet is deformed, the shape of the wrap sheet is followed. It is preferable that the moisture detection unit is also deformed. For that purpose, it is desired that the moisture detection unit has a certain thickness or less. The thickness of the water detection portion is preferably 200 μm or less, more preferably 100 μm or less.

Further, the thickness of the first electrode 61 and the second electrode 62 is preferably thin, preferably 100 μm or less. This is the distance between the first electrode 61 and the second electrode 62 and the distance between the first electrode 61 and the second electrode 62 when each or one of the first electrode 61 and the second electrode 62 is thick. This is because if the aspect ratio of the space portion formed by the thickness of the electrode 62 becomes large, it may be difficult for water to enter between the first electrode 61 and the second electrode 62. When the thickness of the first electrode 61 and the second electrode 62 is 100 μm or less, it has an effect of making it easier for water to adhere between the first electrode 61 and the second electrode 62.

In the first embodiment, the mounting position of the sensor 30 is substantially the central portion on the plane of the absorbent article 10. This position corresponds to the wearer's inseam. However, as long as the object of the present invention can be achieved, the mounting position of the sensor 30 is not particularly limited. From the viewpoint of increasing the reliability of the sensor and reducing the discomfort of the wearer of the water-absorbent article, it is preferable that the sensor is arranged in a portion other than the substantially central portion of the absorbent article.

For example, in the modified example of the first embodiment shown in FIG. 4, the sensor 30 arranged between the back sheet 11 of the absorbent article 15 and the absorber 20 is located at a substantially central portion on the plane of the absorbent article 15. It is not located, but is located at a position shifted in the long side direction. In this embodiment, the stress applied to the sensor 30 is smaller than that in the case where the sensor 30 is located substantially in the center. This makes it possible to provide an absorbent article with a more reliable sensor.

As described above, according to the first embodiment of the present invention, it is possible to provide an absorbent article that can accurately detect the generation of moisture with a simple configuration and cause less discomfort to the wearer.

(Modification 1)
Next, a modification of the sensor used in the absorbent article according to the embodiment of the present invention will be described. FIG. 5 is a diagram schematically showing a modification 1 of the sensor. The sensor 32 shown in the figure is provided with an antenna unit 70 in addition to the water detection unit 60 on the base material 40, and has the same configuration as the sensor 30 included in the absorbent article shown in the first embodiment except for the sensor 32. ..

The antenna unit 70 has a function of communicating the state of the moisture detection 60 to the reading device without directly connecting to the reading device outside the absorbent article 10 by wire. As long as it is possible, the material, shape, and method of the antenna portion 70 are not particularly limited.

Regarding the shape of the antenna portion 70, FIG. 5 schematically shows a so-called dipole antenna assuming communication with the outside by radio waves, but the shape is not limited to this. As the antenna unit 70, an antenna shape suitable for various communication methods can be taken, for example, a loop-shaped antenna is used when communicating with the outside by a magnetic field as described later.

Regarding the communication method with the outside, for example, when the radio wave is used as the communication method to the outside of the absorbent article 10, the following method can be adopted as an example. A reading device is arranged outside the absorbent article 10, the reading device irradiates the sensor with radio waves of a specific frequency, and the antenna unit 70 receives the radio waves. Therefore, the state of the water content detection unit 60 can be recognized by utilizing the fact that the state of the radio wave output from the antenna unit 70 changes depending on the state of the water content detection unit 60.

Further, for example, when a magnetic field is used as a method of communicating the absorbent article 10 to the outside, the following method can be adopted as an example. A reading device provided with a loop-shaped antenna is arranged outside the absorbent article 10, a magnetic field that changes periodically is applied from the loop-shaped antenna, and an electromotive force due to electromagnetic induction is generated in the antenna portion 70. The state of the current due to the electromotive force changes depending on the state of the presence or absence of water in the moisture detection unit 60, and the mutual inductance between the loop-shaped antenna of the reading device and the antenna unit 70 changes. By reading the change, it is possible to recognize the state of the presence or absence of water in the water detection unit 60.

In order for the absorbent article 10 to efficiently communicate with the reading device outside the absorbent article 10, it is preferable to use a material having high conductivity for the antenna portion 70. Specific examples of the material constituting the antenna portion 70 include the same materials as those constituting the conductor.

(Modification 2)
FIG. 6 is a diagram schematically showing a modification 2 of the sensor. The sensor 34 shown in the figure includes a circuit unit 80 in addition to the moisture detection unit 60 and the antenna unit 70, and has the same configuration as the sensor 32 shown in the modified example 1 except for the circuit unit 80.

The circuit unit 80 is arranged between the moisture detection unit 60 and the antenna unit 70, controls the moisture detection unit 60, controls the antenna unit 70, and communicates between the absorbent article 10 and an external reading device. Do it efficiently. More specifically, the circuit unit 80 detects water content by applying a DC voltage, an AC voltage, or a specific electric signal to the water content detection unit 60.

When, for example, a DC voltage is applied from the circuit unit 80 to the moisture detection unit 60, the current of the applied DC voltage source changes depending on the presence or absence of moisture in the moisture detection unit 60. By utilizing this phenomenon, the presence or absence of water can be recognized by the circuit unit 80. Further, when a specific electric signal is applied from the circuit unit 80 to the moisture detection unit 60, the amount of change in the signal changes depending on the presence or absence of moisture in the moisture detection unit 60. By utilizing this phenomenon, the presence or absence of water can be recognized by the circuit unit 80.

As an example of applying a specific electric signal from the circuit unit 80 to the water content detection unit 60, for example, the circuit unit 80 may output a rectangular wave having a specific frequency to the water content detection unit 60. Then, by utilizing the phenomenon that the rectangular wave signal changes depending on the presence or absence of moisture in the moisture detection unit 60, the presence or absence of moisture can be recognized by the circuit unit 80.

Further, the circuit unit 80 rectifies the voltage generated by the antenna unit 70, and changes the electrical characteristics of the antenna unit 70, for example, the impedance, so that communication between the antenna unit 70 and an external reading device can be performed. Can be performed efficiently.

The circuit unit 80 is preferably an assembly of functional elements arranged on a substrate and designed to realize a desired operation. The functional element is, for example, a transistor, a resistor, a capacitance, a diode, or the like, and the circuit unit 80 includes at least one of these.

The circuit unit 80 is preferable because it can realize a thin and inexpensive sensor by including a thin film transistor containing carbon nanotubes. FIG. 7 shows a schematic cross-sectional view of a thin film transistor containing carbon nanotubes in the semiconductor layer. The thin film transistor shown in FIG. 7 has a gate electrode 81, a gate insulating film 82, a semiconductor layer 85, a source electrode 83, and a drain electrode 84 formed on a base material 43.

The base material 43 may be different from the base material on which the sensor is formed, but is preferably common (integrated) with the base material on which the sensor is formed.

The material constituting the gate electrode 81 is, for example, at least one selected from the group consisting of gold, copper, silver, nickel, tin, bismuth, lead, zinc, palladium, platinum, aluminum, tungsten, molybdenum and carbon. Inorganic substances containing elements are preferable, but the materials and forming methods thereof are not particularly limited as long as desired electrical properties can be obtained.

The material constituting the gate insulating film 82 is not particularly limited as long as the desired insulating property can be obtained. For example, silicon oxide, siloxane, alumina, polyimide and the like can be mentioned. The material constituting the gate insulating film 82 is preferably a material that can be formed by a printing technique from the viewpoint of reducing the manufacturing cost.

The semiconductor layer 85 contains at least semiconductor-type carbon nanotubes, and controls the current between the source electrode 83 and the drain electrode 84 by an electric field from the gate electrode 81 via the gate insulating film 82. In order to control the current between the source and drain electrodes with high accuracy by the electric field generated by the gate electrode 81, it is preferable that the ratio of the semiconductor type carbon nanotubes is high. Specifically, it is preferable that 80% or more of the carbon nanotubes are of the semiconductor type, and more preferably 90% or more of them are of the semiconductor type.

Further, it is more preferable that the semiconductor layer 85 contains a carbon nanotube composite in which a conjugated polymer is attached to at least a part of the surface. Examples of such a carbon nanotube complex include those disclosed in International Publication No. 2009/139339.

The material constituting the source electrode 83 and the drain electrode 84 may be any conductive material that can be generally used as an electrode. For example, indium tin oxide (ITO), gold, silver, copper, aluminum, polysilicon, conductive polymers, carbon materials and the like can be mentioned. These electrode materials may be used alone, or a plurality of materials may be laminated or mixed. It is preferable that the material constituting the source electrode 83 and the drain electrode 84 is a material that can be formed by a printing technique from the viewpoint of reducing the manufacturing cost.

With the above configuration, in the manufacturing process of the thin film transistor including at least the formation of the semiconductor layer 85, for example, screen printing, gravure printing, offset printing, inkjet method, dispenser coating method, nozzle coating method, drop cast coating method and the like. By using the above, it becomes possible to form a thin film transistor at low cost. Therefore, an inexpensive, highly functional, and thin circuit unit 80 can be realized.

In addition to the thin film transistor, the circuit unit 80 may include functional elements such as a diode, a resistor, and a capacitance. The type of functional element required is not particularly limited, but it is a functional element formed on a substrate by using printing technology from the viewpoint of manufacturing cost and the viewpoint of not impairing the wearing feeling of the wearer of the absorbent article. Is preferable.

From the viewpoint of detecting moisture with higher sensitivity, the sensor 34 is preferably a sensor of a type in which the moisture detection unit 60 detects moisture by directly touching it. On the other hand, the circuit unit 80 and the antenna unit 70 are deteriorated due to changes in characteristics and corrosion due to direct contact with moisture. Therefore, it is preferable to provide a protective layer to prevent direct contact with moisture.

That is, it is preferable that the sensor 34 has a configuration that does not come into contact with moisture except for the moisture detection unit 60. As a specific configuration thereof, for example, the circuit unit 80 and the antenna unit 70 are provided with a protective layer that does not allow moisture to pass through, while the moisture detection unit 60 is provided with a protective layer that allows moisture to pass through. An example is a configuration in which a protective layer is not provided. By adopting such a configuration, it becomes possible to provide a sensor having more durability. This point preferably applies not only to the sensor 34 according to the second modification, but also to all the sensors applied to the present invention.

Further, it is preferable that the antenna portion 70 is as far away from the moisture as possible because the characteristics of the antenna portion 70 may change due to the presence of moisture, which is a dielectric, in the vicinity. Therefore, it is preferable that the antenna portion 70 is arranged in a portion where the top sheet and the back sheet face each other without sandwiching the absorber. Such a portion is, for example, a peripheral portion of the absorbent article 10 according to the first embodiment of the present invention, and FIG. 8 shows an example thereof. In the absorbent article 18 shown in FIG. 8, the sensor 34 is arranged so as to straddle a portion facing the top sheet and the back sheet without sandwiching the absorber 20 and a portion facing the absorbent body 20 sandwiching the absorber 20. The antenna portion is arranged on the facing portion without sandwiching the absorber 20. With such an arrangement, it is possible to suppress fluctuations in the characteristics of the antenna portion due to moisture without the antenna portion coming into contact with the absorber 20 that absorbs and retains moisture.

It should be noted that it is not necessary that all of the antennas are arranged in opposite portions without sandwiching the absorber 20 between the top sheet and the back sheet, and as long as the influence of moisture on the antenna can be reduced, one of the antennas is used. There is no problem even if only the portion is arranged in the facing portion without sandwiching the absorber 20 between the top sheet and the back sheet.

In FIG. 6, the wiring between the moisture detection unit 60 and the circuit unit 80 is shown by one, but this is for a schematic diagram, and the number of the wiring is not particularly limited in the actual sensor. Hereinafter, in the diagram schematically showing the sensor, the number of wires between the moisture detection unit 60 and the circuit unit 80 is not limited to the number shown in the figure.

(Modification 3)
FIG. 9 is a diagram schematically showing a modified example 3 of the sensor. The sensor 36 shown in the figure is formed by forming a moisture detection unit 60, an antenna unit 70, and a circuit unit 80 on the same surface of the base material 40. Of the configurations of the sensors 36 according to the present modification 3, the configurations are the same as those of the sensors 32 and 34 shown in the modifications 1 and 2 except for the points described below.

In the sensor 36 according to the third modification, the moisture detection unit 60, the antenna unit 70, and the circuit unit 80 are formed on the same surface of the base material 40, so that a circuit made of, for example, an IC chip is mounted on the base material. The thickness of the sensor can be reduced as compared with the case where the moisture detection sensor is individually formed or the case where the moisture detection sensor is attached to the base material. Therefore, it is possible to provide an absorbent article that is thin and does not cause discomfort to the wearer.

Here, for example, the fact that the moisture detection unit 60 is formed on the surface of the base material 40 means that at least one of the elements necessary for forming the moisture detection unit is printed by using, for example, a printing technique. As described above, it means that the moisture detection unit 60 is directly formed on the surface of the base material 40.

The printing technique refers to a technique of forming at least one of the materials constituting each part by printing directly on the base material 40. Examples of the printing method include screen printing, gravure printing, offset printing, inkjet method, dispenser coating method, nozzle coating method, drop cast coating method and the like.

As described above, in the method for manufacturing an absorbent article according to the embodiment of the present invention, it is preferable that the printing technique is included in the manufacturing process of the sensor.

By forming the moisture detection unit 60, the antenna unit 70, and the circuit unit 80 on the same surface, the sensor can be manufactured by a simple process as compared with the case where these are formed on both sides. Further, by using the surface on which the moisture detection unit 60, the antenna unit 70, and the circuit unit 80 are not formed as the attachment portion to the absorbent article, it is possible to reduce the area of the entire sensor. Further, since the moisture detection unit 60 and the circuit unit 80 are formed on the same surface, the moisture detection unit 60 and the circuit unit 80 can be integrally formed, and can be manufactured at a lower cost than when they are manufactured separately. It will be possible. Further, one of the steps of forming the circuit unit 80 is used by using at least one of the conductive materials used for the circuit unit 80 and the same material for the conductive material forming the moisture detection unit 60. It is possible to form the moisture detection unit 60, which is preferable from the viewpoint of simplification of the manufacturing process and cost reduction, and it is not necessary to use a process or a material for connecting the circuit unit 80 and the moisture detection unit 60. It also has the effect of.

(Modification example 4)
FIG. 10 is a diagram schematically showing a modified example 4 of the sensor. The sensor 38 shown in the figure is provided with a moisture detection unit 60 and a circuit unit 80 on the first base material 41, and an antenna unit 70 on the second base material 42. Other than that, the configuration is the same as that of the sensor 36 shown in the modified example 3.

The first base material 41 and the second base material 42 are adhered to each other at the portion of the double arrow indicated between them. That is, the sensor 38 has a structure in which the base material 41 on which the circuit portion 80 is formed and the base material 42 on which the antenna portion 70 is formed are bonded together. The bonding area and the bonding method are not particularly limited as long as an electrical connection is established between the first base material 41 and the second base material 42 at a necessary position. For example, the smaller area of the first base material 41 and the second base material 42 may be adhered to the other over the entire surface. Further, only a part of the base material having the smaller area may be adhered to the other base material. Further, examples of the bonding method include, but are not limited to, bonding using an adhesive or thermocompression bonding.

In FIG. 10, a sensor having a configuration in which the first base material 41 is larger than the second base material 42 is shown, but the magnitude relationship between them is not particularly limited. The relationship between the thickness of the first base material 41 and the thickness of the second base material 42 is not particularly limited, but it is preferable that the second base material 42 is thinner than the first base material 41.

By adopting the configuration shown in the present modification 4, it is possible to manufacture some of the elements necessary for the sensor, the moisture detection unit, the circuit unit, and the antenna unit, on different base materials, and each element can be manufactured. It is possible to manufacture with only the minimum manufacturing process required for the above. For example, in the case of the configuration shown in FIG. 10, only the antenna portion needs to be manufactured on the second base material 42, and functional elements such as those required in the circuit portion 80, such as a transistor, a resistor, a capacitance, and a diode, need to be manufactured. There is no need to go through the process of manufacturing such as. Therefore, wasteful materials are not used during manufacturing, electric power for manufacturing, industrial water, and the like can be reduced, and the environmental load during sensor manufacturing can be reduced.

Further, the thickness of the first base material 41 and the second base material 42 can be arbitrarily selected according to the conditions such as the respective functions and manufacturing processes, so that the absorbent article is inexpensive and has an improved wearing feeling. Can be provided. Specifically, for example, since the first base material 41 includes a moisture detection unit 60 and a circuit unit 80, it is necessary to manufacture the first base material through a relatively complicated manufacturing process. It is preferable to use a relatively thick base material in order to improve the controllability during the process so that the process can be smoothly performed. On the other hand, the second base material 42 includes only the antenna portion 70, and can be manufactured only by forming a conductor pattern for forming the antenna. Therefore, since the number of manufacturing steps and the number of heat treatment steps are small, it is possible to use a relatively thin base material. That is, although the thickness of the bonded portion is increased as compared with the case where all the elements are made of the same base material, the portion of only the second base material 42 can be made thinner. Therefore, it is possible to provide a sensor having a better fit as a whole.

The antenna unit 70 is preferably manufactured in a large size from the viewpoint of improving characteristics such as communication distance and communication speed. On the other hand, from the viewpoint of cost and the wearing feeling of the wearer, it is desirable that the antenna portion 70 is manufactured in a small size. In determining the size of the antenna portion 70, it is preferable to consider the relationship between these trade-offs and the necessary characteristics when designing.

At this time, as shown in the present modification 4, the first base material 41 forming the circuit portion 80 and the moisture detection portion 60 and the second base material 42 forming the antenna portion are used, and the second base material 42 is used. By thinning the base material 42 of the above material, the material cost can be reduced and the thickness can be increased so as not to increase the discomfort to the wearer. In this way, the restriction on increasing the size of the antenna portion 70 is reduced, and the communication characteristics of the absorbent article with the outside can be improved.

When at least two base materials are bonded together as in the present modification 4, an electrical connection is required between the base materials. Therefore, in general, it is preferable to make electrical connection by laminating the base materials so that the conductive parts of each substrate are in physical contact with each other. Hereinafter, making an electrical connection by such a method is referred to as "making a physical connection".

On the other hand, when making a physical connection, it is necessary to strictly control the positional relationship between the base materials and then bond them together, which is likely to lead to an increase in cost. When there is such a concern, it is preferable to bond the base materials together so that the conductive parts of each substrate do not come into contact with each other. Hereinafter, making an electrical connection by such a method is referred to as "making a non-contact connection". By making a non-contact connection, it is not necessary to strictly align the base materials with each other, and it becomes possible to manufacture the sensor at a lower cost.

For example, when a non-contact connection is made in a sensor having a circuit portion and an antenna portion, the conductive portion of the circuit portion and the antenna are not in direct contact with each other. That is, the conductive portion of the circuit portion and the antenna are not in contact with each other. It is possible to make a non-contact connection not only with the sensor according to the present modification 4 but also with the sensors according to the above-mentioned modifications 2 and 3.

When making a non-contact connection, for example, in the modification 4, the electrical connection between the circuit unit 80 and the antenna unit 70 can be realized by using an electric field or a magnetic field individually or in combination. As a method of making an electrical connection by coupling an electric field, for example, a pattern that capacitively couples to each other is arranged in a circuit portion 80 and an antenna portion 70, and both are capacitively coupled via a material having an electrically insulating property. There is a method of combining. Further, as a method of making an electrical connection by coupling a magnetic field via a second base material 42, a loop-shaped conductor pattern is formed in each of the circuit portion 80 and the antenna portion 70, and an electromagnetic induction method between the two patterns is adopted. There is a method of making an electrical connection.

(Moisture detection system)
FIG. 11 is a diagram schematically showing a moisture detection system 100 using the absorbent article 10 according to the embodiment of the present invention. The moisture detection system 100 shown in the figure is composed of an absorbent article 10 and a reading device 90 which is a means for wirelessly communicating with the absorbent article 10. The absorbent article 10 includes the top sheet, the absorbent body, the back sheet, and the like shown in the embodiments so far, but is omitted in FIG. 11.

Information on the presence or absence of moisture inside the absorbent article 10 is communicated between the absorbent article 10 and the reading device 90 without connecting a physical wire, and the moisture state of the absorbent article 10 is communicated by the reading device 90. Can be detected. Although omitted in FIG. 11, the reading device 90 is connected to the outside of the device and a network line, and includes a system for notifying the wearer or a worker exchanging absorbent articles as needed.

By constructing the system shown above, it is possible to notify the moisture state of the absorbent article, and by replacing the absorbent article when necessary, the wearer of the absorbent article continues to be in a comfortable state. can do.

10 Absorbent article 11 Back sheet 12 Top sheet 15 Absorbent article 18 Absorbent article 20 Absorber 21 Core 22 Wrap sheet 30, 32, 34, 36, 38 Sensor 40 Base material 41 First base material 42 Second base Material 43 Base material 60 Moisture detection unit 61 First electrode 62 Second electrode 63 Base material 70 Antenna part 80 Circuit part 81 Gate electrode 82 Gate insulation layer 83 Source electrode 84 Drain electrode 85 Semiconductor layer 90 Reading device 100 Moisture detection system

Claims (16)

An absorbent article comprising at least a top sheet, an absorber, a back sheet, and a sensor having a moisture detector.
The absorber comprises a core that absorbs moisture and a wrap sheet that covers the core.
The sensor is placed between the wrap sheet and the back sheet of the absorber.
An absorbent article characterized in that the thickness of the sensor is 1 mm or less. The absorbent article according to claim 1, wherein the moisture detection unit includes a conductor, and at least a part of the conductor comes into contact with the wrap sheet. The absorbent article according to claim 1 or 2, wherein the moisture detection portion has a thickness of 200 μm or less. The absorbent article according to any one of claims 1 to 3, wherein the moisture detecting portion includes a conductor, and the thickness of the conductor is 100 μm or less. The absorbent article according to any one of claims 1 to 4, wherein the sensor is configured so as not to come into contact with moisture except for the moisture detection unit. The absorbent article according to any one of claims 1 to 5, wherein the sensor has an antenna portion. The absorbent article according to claim 6, wherein at least a part of the antenna portion is arranged in a portion where the top sheet and the back sheet face each other without sandwiching the absorber. The absorbent article according to any one of claims 1 to 7, wherein the moisture detection unit includes a conductor, and the conductor comprises a pair or more of facing patterns that are not directly connected to each other and contain at least a metal element and an organic component. The absorbent article according to claim 8, wherein the resistance between one or more pairs of facing patterns that are not directly connected to each other of the moisture detection unit is 10 MΩ or less due to contact with moisture. The absorbent article according to any one of claims 1 to 9, wherein the sensor has a circuit portion. The absorbent article according to any one of claims 1 to 10, wherein the sensor has a circuit portion and an antenna portion, and the conductive portion of the circuit portion and the antenna portion do not contact each other. The absorbent article according to claim 10 or 11, wherein the sensor is formed by forming the moisture detection unit and the circuit unit on the same surface on the same substrate. The absorbent article according to any one of claims 10 to 12, wherein at least one kind of the conductive material in the circuit section is the same as the conductive material forming the moisture detection section. The absorbent article according to any one of claims 10 to 13, wherein the circuit portion includes a thin film transistor containing carbon nanotubes. The method for manufacturing an absorbent article according to any one of claims 1 to 14, wherein the manufacturing process of the sensor includes a printing technique. A moisture detection system comprising the absorbent article according to any one of claims 1 to 14 and a transmission / reception device provided with means for wirelessly communicating with the absorbent article.

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