A single-sided detection capacitive sensing nonwoven assembly, article, and method of making

Abstract

The application discloses a single-side detection capacitor sensing non-woven fabric assembly, an article and a preparation process, and belongs to the technical field of capacitor type moisture sensing. The application sets a single-side anti-interference capacitor sensing non-woven fabric assembly, forms an aluminum electrode evaporation on a PET film base material, and fixes the electrode on a non-woven fabric base body through point-shaped / strip-shaped local bonding. The electrode gap is water-permeable and air-permeable, and unilateral liquid moisture detection is realized by relying on the double-layer capacitor principle. The film base material can effectively block the backside moisture interference, and the detection false triggering is eliminated from the source. The application also limits a matching disposable absorbent article assembly structure, an intelligent paper diaper monitoring system and a standardized mass production preparation process. The product structure is simple, the detection precision is high, mass production is feasible, and the application is suitable for intelligent paper diaper, incontinence care and other moisture monitoring scenes, and has good practicability and market application prospect.

Description

Technical Field

[0001] This invention relates to the fields of capacitive humidity sensing, disposable hygiene products and intelligent monitoring technology, specifically to a single-sided detection capacitive sensing nonwoven fabric component, product and manufacturing process. Background Technology

[0002] Excrement exposure monitoring is a concept that has become increasingly accepted in incontinence care and smart diaper monitoring scenarios in recent years. It determines the excrement exposure status by monitoring the moisture state of the diaper surface. This is undoubtedly a significant improvement over the previously commonly used method of monitoring the moisture state of the absorbent layer or leak-proof layer of the diaper to indicate diaper changes, because the diaper surface is the layer that comes into contact with human skin and can more accurately reflect the skin sensation of the diaper user and the risk of excrement contact.

[0003] In terms of existing technology, Chinese invention patent authorization announcement number CN120616916B discloses a disposable absorbent product that can realize the function of excrement exposure monitoring. It includes a flow guiding layer, a surface layer, an absorbent layer and a leak-proof layer with the function of excrement exposure monitoring. The flow guiding layer is disposed between the surface layer and the absorbent layer. The first sensing layer is disposed facing the surface layer and the second sensing layer is disposed facing the absorbent layer. When there is flowing excrement exposed on the surface layer, the liquid contained in the excrement will pass through the highly permeable hydrophilic surface layer to reach the flow guiding layer, and enter the absorbent layer through the flow guiding holes of the flow guiding layer. The flow guiding layer is used for both liquid guidance and realizing the function of excrement exposure monitoring.

[0004] The existing excrement exposure monitoring function described above is not perfect. It cannot detect excrement exposure if only the surface layer is damp (making the first sensing layer facing the surface layer damp). The liquid in the excrement needs to penetrate the surface layer to reach the guide layer, and then enter the absorption layer through the guide holes in the guide layer, making the second sensing layer facing the absorption layer damp as well. In this case, loose stools with poor flowability may not be able to pass through the guide holes in the guide layer to enter the absorption layer, meaning they may not be detected. Ideally, excrement exposure monitoring should only require detection of surface layer dampness, without relying on the dampness of the absorption layer. Ideally, it should also shield against moisture interference from the absorption layer and determine the excrement exposure status solely through surface layer dampness detection. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a single-sided detection capacitive sensing nonwoven fabric component, product and manufacturing process, which solves the technical problem that traditional sensing structures rely on the moisture of the absorption layer to achieve detection, or are easily affected by the moisture of the absorption layer and trigger falsely.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention discloses a double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection, comprising a nonwoven fabric substrate, a plastic film substrate, and at least two thin-film flexible metal electrodes. The flexible metal electrodes are formed on one surface of the plastic film substrate, and the side of the plastic film substrate carrying the flexible metal electrodes is bonded to a portion of the same side surface of the nonwoven fabric substrate. The flexible metal electrodes are arranged longitudinally along the nonwoven fabric with predetermined gaps, which are permeable to water and air. The interface between the flexible metal electrodes and the nonwoven fabric substrate is the detection surface, allowing liquid containing electrolytes to pass through the nonwoven fabric substrate to reach the detection surface, achieving moisture detection via double-layer capacitance. The plastic film substrate forms a protective structure, blocking moisture interference from the side away from the detection surface, thereby achieving single-sided detection.

[0007] Furthermore, the flexible metal electrode is a vapor-deposited aluminum electrode.

[0008] Furthermore, at least two of the flexible metal electrodes are arranged in parallel along the longitudinal direction of the nonwoven fabric.

[0009] Furthermore, the flexible metal electrode is fixed to the surface of the nonwoven fabric substrate by dot-like or strip-like adhesive bonding along with the plastic film substrate, rather than being fully sealed with adhesive, so that liquid can pass through the nonwoven fabric substrate to reach the detection surface.

[0010] Furthermore, the plastic film substrate and the thin-film flexible metal electrode have the same planar shape. The plastic film substrate is a one-way protective structure, which can block moisture interference from the side away from the detection surface, and does not block the liquid penetration path on the detection surface side.

[0011] Based on the above core structure, the present invention also provides a disposable absorbent product, comprising an electrode-nonwoven fabric assembly; the electrode-nonwoven fabric assembly serves as the surface nonwoven fabric of the disposable absorbent product, and the side of the electrode-nonwoven fabric assembly with a protective structure faces the absorbent layer; the disposable absorbent product also includes a leak-proof layer, and the overall structure is adapted to intelligent humidity detection scenarios.

[0012] Furthermore, this invention provides an intelligent diaper system device, belonging to an intelligent monitoring supporting system, including disposable absorbent materials, a capacitance detection device, a wireless transmitter, and a wireless receiver; the capacitance detection device includes a metal needle tip, which pierces the non-woven fabric substrate and is electrically connected to the flexible metal electrode for real-time acquisition of surface moisture status signals; the wireless transmitter is used to wirelessly transmit the acquired moisture status signals; the wireless receiver is used to receive the signals emitted by the wireless transmitter and display the moisture status information of the disposable absorbent materials in real time, realizing intelligent monitoring and early warning.

[0013] Based on the single-sided barrier structure of the electrode-nonwoven fabric assembly, the system only responds to the double-layer capacitance change caused by the liquid permeating from the human body side, shielding the reverse humidity interference of the liquid accumulated in the absorption layer, and realizing the intelligent monitoring function of accurate single-time urine wetness identification, no false alarms, and continuous multiple detection.

[0014] Meanwhile, this invention provides an industrial manufacturing method for electrode-nonwoven fabric assemblies, used for mass production of the electrode-nonwoven fabric assemblies, comprising the following steps: S1, substrate selection: selecting PET film with a thickness of 3-15μm and a length of 10-10000 meters as the plastic film substrate, suitable for continuous mass production of rolls; S2, electrode evaporation: vacuum evaporating a pure aluminum layer with a thickness of 20-200nm on one side of the plastic film substrate to form a uniform and dense conductive metal coating layer; S3, electrode slitting: slitting the film substrate after pure aluminum evaporation into long strip electrode structures with a width of 4-40mm, and winding them into standardized electrode substrate rolls; S4, composite molding: selecting hydrophilic nonwoven fabric as the nonwoven fabric substrate, and using a composite equipment to partially composite and bond the substrate with pure aluminum electrodes on one side to the surface of the nonwoven fabric substrate (forming a detection surface), using dot-shaped or strip-shaped partial bonding methods to avoid pore blockage problems, and producing an electrode-nonwoven fabric assembly that is water-permeable, air-permeable, and allows for precise single-sided detection.

[0015] In addition, the present invention also provides a method for manufacturing a disposable absorbent product, which includes the following steps: S1, material preparation: taking electrode-nonwoven fabric assembly, absorbent layer material and leak-proof layer material; S2, layer lamination: using the electrode-nonwoven fabric assembly as the surface nonwoven fabric, with the plastic film protective structure facing the absorbent layer and the detection surface facing the human body, the electrode-nonwoven fabric assembly, absorbent layer and leak-proof layer are sequentially stacked and bonded to form a composite blank; S3, cutting and shaping: the completed roll of composite blank is slit and cut to obtain several independent disposable absorbent product finished products.

[0016] This invention innovatively employs a composite structure, molding flexible metal electrodes onto the surface of a plastic film substrate. The electrode-bearing substrate is then bonded to a localized area on one side of a non-woven fabric substrate using a dotted or strip-shaped non-full-area adhesive bonding method. Water and air permeable gaps are reserved between the electrodes to ensure the overall breathability and water permeability of the assembly. This invention uses the interface between the electrodes and the non-woven fabric as the detection surface, allowing electrolyte liquid to easily pass through the non-woven fabric substrate and contact the detection interface. Accurate moisture detection is achieved based on the principle of double-layer capacitance.

[0017] Compared to existing technologies, the plastic film substrate of this invention combines electrode support and unidirectional protection, eliminating the need for an additional independent protective layer and significantly simplifying the overall structure. This substrate can precisely block moisture interference from the side away from the detection surface while not affecting the liquid penetration detection pathway on that side, achieving a dedicated unidirectional detection effect and fundamentally avoiding the impact of environmental factors on the detection data.

[0018] This invention features a simple and rational structural design with outstanding core performance, effectively addressing the industry pain points of existing technologies that cannot achieve accurate and reliable single-sided (surface layer) moisture detection, or are easily affected by moisture in the absorbent layer, thus failing to achieve reliable excrement exposure monitoring. The product boasts high detection accuracy and strong resistance to back-side moisture interference, making it suitable for core excrement exposure monitoring scenarios such as incontinence care and smart diapers, demonstrating exceptional practicality and adaptability. Furthermore, this invention includes a protective product structure, end-use products, an intelligent system, and a complete set of mass production processes. With precise and reasonable parameters and high industrial feasibility, it enables standardized, large-scale, low-cost production, forming a complete technological closed loop from core sensor substrate and end-use absorbent products to intelligent monitoring systems, possessing extremely high market promotion value and promising industrial application prospects. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the double-layer capacitive sensing electrode-nonwoven fabric assembly that can realize single-sided detection function according to an embodiment of the present invention. Figure 2 for Figure 1 A schematic diagram of the cross-section of the stacked structure; Figure 3 This is a top view schematic diagram of the plastic film substrate and its surface flexible metal electrode in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1 Nonwoven fabric substrate; 2 Plastic film substrate; 3 Flexible metal electrode; 4 Preset gap; 5 Detection surface (the interface where the flexible metal electrode and the nonwoven fabric substrate are bonded); 6 Adhesive point / adhesive strip; 7 Side away from the detection surface (the outer side of the plastic film substrate away from the flexible metal electrode). Detailed Implementation

[0022] The following descriptions of the embodiments are with reference to the accompanying drawings, illustrating specific embodiments in which the present invention can be implemented. The directional and positional terms used in this invention, such as "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings and are therefore intended to illustrate and understand the present invention, and not to limit the scope of protection of the present invention.

[0023] like Figure 1 Figure 3 As shown, this invention is a double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection, comprising a nonwoven fabric substrate 1, a plastic film substrate 2, and at least two thin-film flexible metal electrodes 3. The flexible metal electrodes 3 are formed on one surface of the plastic film substrate 2. The side of the plastic film substrate 2 carrying the flexible metal electrodes 3 is bonded and fixed to a portion of the same side surface of the nonwoven fabric substrate 1 via adhesive points / adhesive strips 6 in a dotted or strip-like adhesive manner, without employing a full-surface adhesive seal structure, thus reserving a pathway for liquid permeation.

[0024] The flexible metal electrodes 3 are arranged along the longitudinal direction of the nonwoven fabric substrate 1, and a preset gap 4 is formed between adjacent flexible metal electrodes 3. The gap 4 has good water and air permeability. The interface between the flexible metal electrodes 3 and the nonwoven fabric substrate 1 forms the detection surface 5. Liquids containing electrolytes can permeate through the nonwoven fabric substrate 1 to the detection surface 5, and the moisture state is detected by the double-layer capacitance sensing principle.

[0025] The plastic film substrate 2 also serves as a protective structure for the overall assembly. The outer side of the plastic film substrate 2 away from the flexible metal electrode 3 is the side 7 facing away from the detection surface. The plastic film substrate 2 can effectively block moisture and humidity from entering from the side facing away from the detection surface 7, eliminating the need for an additional protective layer on the back of the non-woven fabric substrate 1. Structurally, this prevents moisture from the back side from interfering with the detection results, ensuring stable and accurate single-sided detection.

[0026] In a preferred embodiment, the flexible metal electrode 3 is prepared as a metal aluminum vapor deposition electrode using a vacuum evaporation process and formed on the surface of the plastic film substrate 2; at least two flexible metal electrodes 3 are arranged parallel to each other along the longitudinal direction of the nonwoven fabric substrate 1 and are continuous long strip structures, covering only a part of one side of the nonwoven fabric substrate 1 and not completely covering the entire surface.

[0027] When the present invention is in operation, the electrolyte-containing liquid seeps in from the outside of the non-woven fabric substrate 1, penetrates the substrate and reaches the detection surface 5 to complete the capacitive moisture detection; while the moisture on the side 7 away from the detection surface is effectively blocked by the plastic film substrate 2 and cannot contact the detection interface, thus completely eliminating the interference of the back side environment and greatly improving the detection accuracy and stability.

[0028] This invention also provides an industrialized preparation method for electrode-nonwoven fabric assemblies, employing a standardized roll-to-roll mass production process suitable for large-scale batch production. During preparation, PET film with a thickness of 3-15 μm and a length of 10-10000 meters is selected as the plastic film substrate. The substrate size parameters are adapted to continuous roll-to-roll production, avoiding the problems of low processing efficiency and poor product consistency associated with short materials. A 20-200 nm thick pure aluminum layer is deposited on one side of the PET film using a vacuum evaporation process, forming a uniform and dense conductive metal layer to ensure the sensitivity and stability of the electrode's capacitive sensing. After evaporation, the coated film is cut into long strip electrode structures with a width of 4-40 mm, and simultaneously wound up to form electrode substrate rolls, achieving standardized storage of the electrode substrate. Finally, hydrophilic nonwoven fabric was selected as the matrix material. Using specialized composite equipment, a dotted or strip-shaped local bonding process was adopted to partially bond the side of the electrode substrate with the pure aluminum electrode to the surface of the nonwoven fabric matrix. No full glue sealing process was used throughout the process, which fully preserved the water and air permeability of the nonwoven fabric pores and the electrode gap. This resulted in the stable production of electrode-nonwoven fabric assemblies with single-sided accurate detection function. The process is highly controllable and the product yield is high.

[0029] This invention also provides a suitable method for preparing disposable absorbent products, which can be seamlessly integrated with the mass production process of the aforementioned electrode-nonwoven fabric assembly to form a complete product production chain. During production, the raw materials for the electrode-nonwoven fabric assembly, absorbent layer, and waterproof / leak-proof layer prepared according to claim 8 are first prepared. Then, layered lamination is performed, strictly limiting the electrode-nonwoven fabric assembly to the product surface layer, with the side with the protective structure facing the absorbent layer. This ensures that body fluids can penetrate the surface nonwoven fabric and accurately contact the electrode detection surface. Simultaneously, relying on the unidirectional protective properties of the plastic film substrate, the reverse interference of moisture inside the absorbent layer with detection accuracy is prevented. The surface layer, absorbent layer, and leak-proof layer are sequentially stacked, bonded, and fixed to form a complete roll of composite blank. Finally, the continuous blank is slit, cut, and shaped to obtain batch-processed, uniformly sized, independent disposable absorbent products. The production process is simple and efficient, suitable for automated assembly line operations.

[0030] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection, characterized in that, The device includes a nonwoven fabric substrate, a plastic film substrate, and at least two thin-film flexible metal electrodes. The flexible metal electrodes are formed on one surface of the plastic film substrate, and the side of the plastic film substrate carrying the flexible metal electrodes is bonded to a portion of the same side surface of the nonwoven fabric substrate. The flexible metal electrodes are arranged longitudinally along the nonwoven fabric with predetermined gaps, which are permeable to water and air. The interface between the flexible metal electrodes and the nonwoven fabric substrate is the detection surface, allowing liquid containing electrolytes to pass through the nonwoven fabric substrate and reach the detection surface, achieving moisture detection via double-layer capacitance. The plastic film substrate forms a protective structure, blocking moisture interference from the side away from the detection surface, thus enabling single-sided detection.

2. The double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection according to claim 1, characterized in that, The flexible metal electrode is an aluminum vapor-deposited electrode.

3. The double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection according to claim 1, characterized in that, At least two of the flexible metal electrodes are arranged in parallel along the longitudinal direction of the nonwoven fabric.

4. The double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection according to claim 1, characterized in that, The flexible metal electrode is fixed to the surface of the nonwoven fabric substrate by dot-like or strip-like adhesive bonding along with the plastic film substrate, rather than being fully sealed with adhesive, so that liquid can pass through the nonwoven fabric substrate to reach the detection surface.

5. The double-layer capacitive sensing electrode-nonwoven fabric assembly capable of single-sided detection according to claim 1, characterized in that, The plastic film substrate and the thin-film flexible metal electrode have the same planar shape. The plastic film substrate is a one-way protective structure, which can block moisture interference from the side away from the detection surface, and does not block the liquid penetration path on the detection surface side.

6. A disposable absorbent product, characterized in that, The disposable absorbent product includes an electrode-nonwoven fabric assembly as described in any one of claims 1-5; the electrode-nonwoven fabric assembly serves as the surface nonwoven fabric of the disposable absorbent product, with the side of the electrode-nonwoven fabric assembly having a plastic film protective structure facing the absorbent layer, and the detection side of the electrode adhering to the nonwoven fabric facing the human body side; the disposable absorbent product further includes a leak-proof layer.

7. A smart diaper system device, characterized in that, The disposable absorbent material as described in claim 6 further includes a capacitance detection device, a wireless transmitter, and a wireless receiver; the capacitance detection device includes a metal needle tip that pierces the nonwoven fabric substrate and is electrically connected to the flexible metal electrode for collecting a moisture status signal; the wireless transmitter is used to transmit the collected moisture status signal outward; and the wireless receiver is used to receive the signal transmitted by the wireless transmitter and display the moisture status information of the surface layer of the disposable absorbent material.

8. The intelligent diaper system device according to claim 7, characterized in that, Based on the single-sided barrier structure of the electrode-nonwoven fabric assembly, the system only responds to the double-layer capacitance change caused by the liquid permeating from the human body side, shielding the reverse humidity interference of the liquid accumulated in the absorption layer, and realizing the intelligent monitoring function of accurate single-time urine wetness identification, no false alarms, and continuous multiple detection.

9. A method for manufacturing an electrode-nonwoven fabric assembly, characterized in that, The preparation of the electrode-nonwoven fabric assembly according to any one of claims 1-5 comprises the following steps: S1, substrate selection: selecting a PET film with a thickness of 3-15 μm and a length of 10 meters to 10,000 meters as the plastic film substrate; S2, electrode evaporation: vacuum evaporating a pure aluminum layer with a thickness of 20-200 nm on one side of the plastic film substrate to form a complete metal coating layer; S3, electrode slitting: slitting the film substrate after pure aluminum evaporation into long strip electrode structures with a width of 4-40 mm, and winding them into electrode substrate rolls; S4, composite molding: selecting a hydrophilic nonwoven fabric as the nonwoven fabric substrate, and using a composite equipment to partially composite and bond the side of the electrode substrate with the pure aluminum electrode to the surface of the nonwoven fabric substrate, using a dotted or strip-shaped partial bonding method to produce a water-permeable and air-permeable electrode-nonwoven fabric assembly with single-sided detection.

10. A method for manufacturing a disposable absorbent product, characterized in that, The preparation of the disposable absorbent material according to claim 6 includes the following steps: S1, material preparation: taking the electrode-nonwoven fabric assembly, absorbent layer material, and leak-proof layer material obtained according to claim 9; S2, layer lamination: using the electrode-nonwoven fabric assembly as the surface nonwoven fabric, with the plastic film protective structure facing the absorbent layer and the detection surface facing the human body, the electrode-nonwoven fabric assembly, absorbent layer, and leak-proof layer are sequentially stacked and bonded to form a composite blank; S3, cutting and shaping: slitting and cutting the completed roll of composite blank to obtain several independent disposable absorbent product finished products.

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