Pressure-sensitive layer, pressure-sensitive sensor and fabrication method based on multi-directional interconnected continuous network structure

Abstract

This invention belongs to the field of flexible sensing technology, and relates to a pressure-sensitive layer, a pressure-sensitive sensor, and a manufacturing method based on a multi-directional interconnected continuous network structure. The pressure-sensitive layer is composed of parallel composite fibers, including parallel composite conductive fibers. These parallel composite conductive fibers are helical, with their central axis oriented along the thickness direction of the pressure-sensitive layer. The two components of each parallel composite conductive fiber are designated as a first component (the substrate is a first non-conductive polymer) and a second component (the substrate is a second non-conductive polymer), with only the first component containing conductive particles. Adjacent parallel composite fibers adhere to each other at helical contact points, forming a multi-directional interconnected continuous network structure. The pressure-sensitive sensor includes this pressure-sensitive layer. The manufacturing method involves fabricating the pressure-sensitive layer by weaving a spacer fabric followed by post-processing or vertically forming a web, and then composited with a functional layer. This invention achieves high signal stability and long-term stability in the pressure-sensitive sensor, making it suitable for applications such as smart wearables.

Description

Technical Field

[0001] This invention belongs to the field of flexible sensing technology, and relates to a pressure-sensitive layer, a pressure-sensitive sensor, and a manufacturing method based on a multi-directional interconnected continuous network structure. Background Technology

[0002] As an emerging type of flexible sensor, fabric pressure sensors offer superior wearability and comfort compared to traditional silicon-based or thin-film sensors due to their breathability and moisture permeability. These characteristics have led to the increasing application of fabric sensors in fields such as smart wearable devices, health monitoring, motion detection, human-computer interaction, and electronic skin.

[0003] Existing pressure sensors often struggle to achieve both high signal stability and long-term stability.

[0004] For example, patent applications CN117606652A and CN120158864A disclose an integrally molded piezoresistive flexible sensor based on warp-knitted spacer fabric. This type of sensor integrates electrode yarns onto the surface layer of the spacer fabric, with the spacer layer connecting the two surface layers by insulating yarns. The resistive piezoresistive response is achieved through changes in the contact resistance of the electrode yarns. However, this sensor can only trigger a resistive response under relatively high pressure (when the spacer fabric surface layers are in contact with each other), resulting in a narrow detection range and difficulty in effectively detecting low-pressure changes, thus limiting its application in high-resolution signal testing scenarios.

[0005] Patent CN116288892B discloses a piezoresistive sensor based on weft-knitted spacer fabric. The upper and lower layers are electrode layers, and the spacer layer is a piezoresistive sensitive layer. The pressure-sensitive yarns in adjacent rows of the piezoresistive sensitive layer are not connected. When compressed, the contact and separation between the yarns are random, resulting in large resistance fluctuations, which seriously affects the signal stability of the sensor.

[0006] Patent CN120702636B discloses a flexible piezoresistive sensing array based on a weft-knitted spacer fabric with a triangular truss mesh structure. Its sensing area is formed by a five-layer integrated knitting structure consisting of an encapsulation layer, an electrode layer, a piezoresistive sensitive layer, another electrode layer, and an encapsulation layer. Adjacent horizontal rows of conductive yarns are connected end-to-end to form a cross-linked triangular truss mesh structure. Under cyclic compression testing conditions with pressure amplitudes ranging from 0 to 50 kPa, after 100,000 cycles of compression, the baseline resistance change rate under zero pressure does not exceed 5%. However, the physical binding based on the knitted structure is still relatively loose. Under long-term external pressure, friction, or tension, the yarn contact points are prone to slippage, damaging the original fixed-point structure, causing signal drift, and significantly reducing long-term stability. Furthermore, the inherent viscoelastic properties of textile materials cause the stress-resistance curves during loading and unloading to not coincide, resulting in a hysteresis effect.

[0007] Currently, several research and technical solutions have improved sensor performance by employing composite conductive fibers. Patent CN111678424B discloses a flexible tensile strain sensor based on core-sheath fibers, where the core layer is an elastic polymer and the sheath layer is an elastic polymer doped with carbon black nanoparticles. The sensor exhibits high tensile strength and a large tensile strain operating range. Patent application CN104726959A discloses a helical three-component composite conductive fiber, which, after alkali treatment, forms PET / PTT or PET / PBT parallel composite conductive fibers. This type of fiber possesses excellent tensile resilience and comfort. Patent application CN116157036A proposes a conductive fiber with a metal layer disposed on the surface of the helical coiled fiber, solving the discomfort of conductive fibers embedded in textiles. Patent CN107142554B discloses a single-layer fabric sensor based on a core-sheath structure piezoresistive fiber, where the core layer is a non-conductive material and the sheath layer is a thermoplastic polymer containing carbon-based conductive particles. Under pressure, continuous conductive channels are formed between the contacting monofilaments, causing a change in the overall resistance of the sensor. Patent application CN120800606A discloses a pressure-sensitive fabric based on composite conductive fibers. The pressure-sensitive yarn is a composite conductive fiber obtained by combining conductive and non-conductive yarns obtained through melt spinning. The fabric is then woven from the composite conductive fibers and non-conductive yarns. However, the "combining" and "weaving" processes are not fully disclosed. Based on the accompanying drawings, the "combining" process can be understood as a "plying" process, and the pressure-sensitive fabric prepared by this "weaving" process is a single-layer pressure-sensitive fabric. Single-layer pressure-sensitive fabrics have high sensitivity but limited load-bearing capacity. The literature (Scalable fabrication of all-fabric piezoresistive sensors via binder-free, in-situwelding of carbon nanotubes on bicomponent nonwovens, Adv. Fiber Mater., 2024, 6: 120-132) discloses a pressure-sensitive sensor based on a core-sheath structure of thermally fused fiber web, wherein the sheath is PE and the core is PP; the flatly arranged fibers are thermally fused into a web and then impregnated and coated with carbon nanotubes. The multilayer carbon nanotube-coated fiber web is stacked and assembled into a three-dimensional piezoresistive sensitive layer. The direction of pressure is perpendicular to the fiber orientation direction, resulting in low stress transmission efficiency and weak fiber web support, which is prone to permanent deformation or hysteresis effect.

[0008] While the aforementioned research and technologies have improved the performance of pressure sensors to some extent, they have not solved the problem that existing three-dimensional pressure sensors struggle to simultaneously achieve high signal stability and long-term stability. Therefore, further in-depth research is necessary to develop pressure sensors that combine both high signal stability and long-term stability. Summary of the Invention

[0009] The purpose of this invention is to solve the problems existing in the prior art and to provide a pressure-sensitive layer, a pressure-sensitive sensor, and a manufacturing method based on a multi-directional interconnected continuous network structure.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A pressure-sensitive layer based on a multi-directional interconnected continuous network structure is composed of parallel composite fibers, including parallel composite conductive fibers.

[0012] The parallel composite conductive fibers are spiral-shaped, with their central axis oriented along the thickness direction of the pressure-sensitive layer;

[0013] The two components in the parallel composite conductive fiber are referred to as the first component and the second component, respectively. Only the first component contains conductive particles. The substrate of the first component is the first non-conductive polymer, and the substrate of the second component is the second non-conductive polymer.

[0014] Adjacent parallel composite fibers adhere to each other at the helical contact points, forming a multi-directional interconnected continuous network structure.

[0015] The pressure-sensitive sensor of this invention combines high signal stability and long-term stability for the following reasons:

[0016] The adhesion points in the pressure-sensitive layer divide it into multiple structural sub-layers along the thickness direction, creating a multi-layered micronetwork. Under pressure, each micronetwork layer collapses sequentially along the thickness direction, and the conductive first component of the parallel composite conductive fibers in the micronetwork layer contacts each other layer by layer along the thickness direction. This results in a progressively increasing contact resistance change, forming a multi-level, gradual resistance variation. Since the contact sequence and contact area of ​​each micronetwork layer are determined by the adhesion points and the interlayer distance, this structure forms a relatively definite contact separation resistance structure, making the contact resistance more stable. This effectively avoids the resistance abrupt change problem caused by random point contact in traditional fabric sensors based on fabric structures, reduces resistance fluctuations caused by contact interface instability due to the difficulty in controlling the contact position and contact area, thereby reducing signal jitter and achieving high stability in signal output.

[0017] The geometric structure of the multi-directional interconnected continuous network achieves excellent three-dimensional elastic support, resulting in strong sensor load-bearing capacity and a large compressive strain operating range. Furthermore, the network structure formed by adhesion exhibits high structural stability, effectively dispersing pressure and avoiding stress concentration. After unloading, the multi-directional stress release path facilitates rapid structural recovery while reducing plastic deformation of the material. This allows the sensor to exhibit excellent deformation resilience under pressure, rapidly returning to its initial state after compression, reducing hysteresis effects, and preventing structural collapse and performance degradation caused by long-term compression, thereby improving the long-term stability of the pressure sensor. Compared to sponge-based high-resilience sensors, the pressure-sensitive layer of this invention has better air permeability, facilitates drainage and ventilation, and is less prone to prolonged water accumulation, reducing the risk of changes in conductivity or mechanical properties due to humidity.

[0018] As a preferred technical solution:

[0019] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the shrinkage rate of the first non-conductive polymer is less than that of the second non-conductive polymer. This allows conductive particles to be distributed along with the first non-conductive polymer on the outside of the spiral fiber. The conductive particles of different parallel composite conductive fibers are more likely to come into contact, which makes it easier to cause changes in contact resistance. The pressure-sensitive sensor containing this pressure-sensitive layer will have higher sensitivity.

[0020] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the shrinkage difference between the first non-conductive polymer and the second non-conductive polymer is 1.92% to 8.88%.

[0021] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the first non-conductive polymer and the second non-conductive polymer have different melting temperatures, with a difference of 10~70℃.

[0022] As described above, a pressure-sensitive layer based on a multidirectional interconnected continuous network structure comprises conductive particles selected from one or more of carbon black, carbon nanotubes, graphene / graphite, MXene, and conductive polymers; in the first component of the parallel-type composite conductive fiber, the weight percentage of conductive particles is 0.5% to 10%; the resistivity of the parallel-type composite conductive fiber is 10 ohms. 3 ~7.8×10 6 Ω / cm.

[0023] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, two adjacent parallel composite fibers are bonded together at the helical contact point by heat setting. During heat setting, the non-conductive polymer in the parallel composite fibers melts at least partially.

[0024] As described above, the pressure-sensitive layer based on a multi-directional interconnected continuous network structure further includes parallel composite non-conductive fibers;

[0025] The parallel composite non-conductive fibers are spiral-shaped, with their central axis oriented along the thickness direction of the pressure-sensitive layer;

[0026] The two components in the parallel composite non-conductive fiber are referred to as the first component and the second component, respectively. The substrate of the first component is the third non-conductive polymer, and the substrate of the second component is the fourth non-conductive polymer.

[0027] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the shrinkage difference between the third non-conductive polymer and the fourth non-conductive polymer is 1.55% to 15.6%.

[0028] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the third non-conductive polymer and the fourth non-conductive polymer have different melting temperatures, with a difference of 10~70℃.

[0029] In the pressure-sensitive layer based on a multi-directional interconnected continuous network structure as described above, the first to fourth non-conductive polymers are each independently selected from one or more of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polypropylene terephthalate (PTT), polyamide (PA), polyester thermoplastic elastomer (TPEE), and polyurethane elastomer (TPU).

[0030] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the difference in the number of spirals between the parallel composite conductive fibers and the parallel composite non-conductive fibers is 0.5 to 1 / mm. This avoids the parallel composite non-conductive fibers completely surrounding the parallel composite conductive fibers, and preserves the conductive particles of the parallel composite conductive fibers with the exposed surface of the first component as potential contact surfaces.

[0031] As described above, the pressure-sensitive layer based on a multidirectional interconnected continuous network structure has a single filament diameter of 10~35μm and a multifilament fineness of 100~800dtex for the parallel composite conductive fiber; a single filament diameter of 5~15μm and a multifilament fineness of 100~800dtex for the parallel composite non-conductive fiber; and the single filament cross-sectional shape of the parallel composite conductive fiber or the parallel composite non-conductive fiber is circular, dumbbell-shaped or gourd-shaped.

[0032] As described above, in a pressure-sensitive layer based on a multi-directional interconnected continuous network structure, the weight percentage of parallel composite conductive fibers in the pressure-sensitive layer is 50% to 100%; in the parallel composite conductive fibers or parallel composite non-conductive fibers, the volume ratio of the first component to the second component is 5:95 to 50:50.

[0033] The present invention also provides a pressure-sensitive sensor, including a pressure-sensitive layer and other functional layers, the other functional layers including a first electrode layer and a second electrode layer, the first electrode layer, the pressure-sensitive layer and the second electrode layer being arranged sequentially from top to bottom, and the pressure-sensitive layer being a pressure-sensitive layer based on a multi-directional interconnected continuous network structure as described in any of the above claims.

[0034] As a preferred technical solution:

[0035] As described above, the pressure-sensitive sensor also includes a first insulating encapsulation layer and a second insulating encapsulation layer. The first insulating encapsulation layer is located above and adjacent to the first electrode layer, and the second insulating encapsulation layer is located below and adjacent to the second electrode layer.

[0036] As described in any of the preceding claims, the pressure-sensitive sensor has a thickness of 2.5~33mm, and the thickness ratio of the pressure-sensitive layer is 80%~98%; the pressure-sensitive sensor undergoes 100,000 cycles of compression under compressive stress of 0~50kPa, and the baseline resistance change rate is ≤4.2%; the single loading and unloading hysteresis error of the pressure-sensitive sensor is ≤3.7%; thus, the pressure-sensitive sensor of the present invention has high signal stability and long-term stability.

[0037] The present invention also provides a method for preparing a pressure sensor as described in any of the preceding claims. The method involves using parallel composite fibers as spacer yarns and weaving them together with yarns used to form other functional layers using a double-needle bed warp knitting process, a double-sided weft knitting process, or a double-layer weaving process to create a spacer fabric. The spacer fabric is then treated so that two adjacent parallel composite fibers adhere to each other at the helical contact point, thereby obtaining the pressure sensor. This preparation process does not require changes to the traditional production method and has the capability for large-scale manufacturing.

[0038] Alternatively, as described in any of the preceding methods, a pressure-sensitive sensor can be fabricated as follows: after vertical web forming technology is used to vertically shape parallel composite fibers, the fibers are processed to allow adjacent parallel composite fibers to adhere to each other at the helical contact points, thus obtaining a pressure-sensitive layer. The pressure-sensitive layer is then combined with other functional layers by stacking, bonding, or sewing to form a single unit, thereby obtaining the pressure-sensitive sensor. The pressure-sensitive layer is a fiber web fabric formed by heat setting after vertical web forming technology to vertically shape parallel composite fibers. This fabrication process does not require changes to traditional production methods and has the capability for large-scale manufacturing.

[0039] Beneficial effects:

[0040] (1) The present invention uses a multi-directional interconnected continuous network structure formed by parallel composite conductive fibers and parallel composite non-conductive fibers in the pressure-sensitive layer to cause each micro-network layer to collapse sequentially along the thickness direction. The first conductive component contacts layer by layer to form a relatively determined contact and separation resistance structure, which avoids resistance mutation and fluctuation caused by random point contact, reduces signal jitter, and achieves high signal stability of the pressure-sensitive sensor.

[0041] (2) The geometric structure of the multi-directional interconnected continuous network of the present invention provides excellent three-dimensional elastic support, the sensor has strong load-bearing capacity, and the network structure has high structural stability, which can effectively disperse pressure, avoid stress concentration, and the multi-directional stress release path after unloading helps the structure to recover quickly, reduce the plastic deformation and hysteresis effect of the material, avoid structural collapse and performance degradation caused by long-term compression, and improve the long-term stability of the pressure sensor. Attached Figure Description

[0042] Figures 1-3 This is a schematic diagram of the pressure-sensitive layer in Embodiment 1 of the present invention. Figure 1 It is a 3D image. Figure 2 This is a top view. Figure 3 This is a side view;

[0043] Among them, 1-pressure-sensitive layer, 2-component containing non-conductive polymer with higher shrinkage rate, 3-component containing non-conductive polymer with lower shrinkage rate, 4-adhesion point, 5-parallel composite fiber. Detailed Implementation

[0044] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] To ensure that the performance of the substances used in each embodiment is fully disclosed, the manufacturer information of the substances is specified in this invention; in addition, products from other manufacturers that conform to the limitations of this invention are also applicable.

[0046] The following are the test methods for the relevant performance indicators in each embodiment:

[0047] Shrinkage: The shrinkage rates of the two components of the parallel composite fiber cannot be directly measured experimentally. The difference can only be estimated by theoretical formula. This difference is approximately estimated by the experimentally measured helical crimp structure parameters (cross-sectional shape and longitudinal crimp structure of the parallel composite fiber) based on the relationship in the literature (The crimp curvature of bicomponent fibers[J].Journal of Textile Institute, 1981, 73(6): 253-263). The relationship is as follows:

[0048] For parallel composite fibers with a circular cross-sectional shape:

[0049] ;

[0050] t=p / ;

[0051] In the formula, This represents the difference in shrinkage rates between the two components. The longitudinal three-dimensional helical curl curvature of the fiber (unit: mm) -1 ); Let be the radius of the circle (in mm); t is the distance p (in mm) from the interface between the two components to the center of the circle, and the radius of the circle. The ratio, i.e., t = p / When the volume ratio of the two components is 50:50, the interface coincides with the center of the circle. =0, t=0; when the interface approaches the outer boundary of the fiber = , t=1;

[0052] For parallel composite fibers with a dumbbell or gourd-shaped cross-section (the cross-section can be approximated as two overlapping circular structures):

[0053] ;

[0054] In the formula, This represents the difference in shrinkage rates between the two components. The longitudinal three-dimensional helical curl curvature of the fiber (unit: mm) -1 ); The radius of the overlapping circular unit (in mm); t is the distance p (in mm) from the interface between the two groups to the center of the circle and the radius of the circle. The ratio, i.e., t = p / ;

[0055] In the above formula, the longitudinal three-dimensional helical curl curvature of the fiber The approximate estimation of the relationship is based on the regular three-dimensional helical geometry of the parallel composite fiber monofilaments, as shown in the following formula:

[0056] ;

[0057] ;

[0058] In the formula, The radius of the cylindrical surface containing the three-dimensional helical curve; The cylinder length (i.e., pitch) corresponding to a complete spiral. The number of spiral curls per unit length (mm).

[0059] Baseline resistance change rate: First, the sensor is allowed to stand for 24 hours to reach equilibrium in an environment with a temperature of 20±2℃ and a relative humidity of 65%±2%. Then, the resistance is measured under zero pressure and recorded as [value missing]. Subsequently, the sensor was cyclically compressed 100,000 times under a compressive stress of 0–50 kPa at a loading frequency of 5 Hz. After the cyclic compression was completed, the sensor was left to stand for 2 hours at a temperature of 20 ± 2℃ and a relative humidity of 65% ± 2%, and its resistance was measured under zero pressure, recorded as follows. Calculate the rate of change of baseline resistance using the following formula:

[0060] ;

[0061] The baseline resistance change rate reflects whether a material or structure undergoes permanent deformation, contact degradation, or changes in the conductive network under long-term operation.

[0062] Hysteresis error of the pressure sensor during single loading and unloading: The sensor was allowed to stand for 24 hours to reach equilibrium in an environment with a temperature of 20±2℃ and a relative humidity of 65%±2%. Loading and unloading tests were then conducted within the range of 0~50kPa at a loading and unloading rate of 10mm / min. The resistance corresponding to the 50kPa pressure is... Under the same compressive stress, compare the resistance difference output during loading and unloading processes. Take its maximum value Calculate the hysteresis error using the following formula:

[0063] ;

[0064] Hysteresis error reflects the degree to which the output response does not coincide during the loading and unloading process, and is used to evaluate the resilience and signal consistency of the sensor.

[0065] Relative resistance change: The sensor was allowed to stand still for 24 hours at a temperature of 20±2℃ and a relative humidity of 65%±2%, and the resistance was measured under zero pressure. This resistance was recorded as... Subsequently, an acrylic circular plate with a diameter of 2cm was placed on the sensor surface. Standard weights with masses of 10g, 20g, 50g, 100g, 200g, 300g, 400g, and 500g were sequentially loaded onto the plate. The resistance value of the sensor was measured under each load and recorded as follows. Calculate the relative rate of change of resistance of the sensor under different pressure conditions using the following formula:

[0066] ;

[0067] The relative change in resistance reflects the degree of resistance response of the sensor under applied pressure and can be used to evaluate the pressure response characteristics of the sensor.

[0068] In the following embodiments, only the first component of the parallel composite conductive fiber is doped with substances other than the substrate (conductive particles), while the other components contain only the substrate.

[0069] Example 1

[0070] A method for fabricating a pressure-sensitive sensor, the specific steps of which are as follows:

[0071] (1) Preparation of materials;

[0072] Parallel-type composite conductive fiber: The first component's substrate is a first non-conductive polymer (PET, melting point 265℃), which is doped with conductive particles (carbon nanotubes, manufactured by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, catalog number TNIM1), with the conductive particles accounting for 5.6% of the weight of the first component; the second component's substrate is a second non-conductive polymer (PBT, melting point 225℃); the shrinkage difference between the first and second non-conductive polymers is 8.88%, with the first non-conductive polymer having a smaller shrinkage rate than the second; the volume ratio of the first to the second component is 10:90; the parallel-type composite conductive fiber is helical, with a circular monofilament cross-section, a monofilament diameter of 12μm, a multifilament fineness of 150dtex, 4 helices / mm, a crimp radius of 0.32mm, and a resistance of 2.5×10⁻⁶. 4 Ω / cm;

[0073] Parallel composite non-conductive fiber: The matrix of the first component is the third non-conductive polymer (PET, melting point 265℃), and the matrix of the second component is the fourth non-conductive polymer (PBT, melting point 225℃); the shrinkage difference between the third and fourth non-conductive polymers is 3.58%, and the shrinkage of the third non-conductive polymer is less than that of the fourth non-conductive polymer; the volume ratio of the first component to the second component is 15:85; the parallel composite non-conductive fiber is helical, the monofilament cross-section is circular, the monofilament diameter is 10μm, the multifilament fineness is 100dtex, the number of helices is 3 / mm, and the crimp radius is 0.41mm;

[0074] The yarns used to form the first insulating encapsulation layer and the yarns used to form the second insulating encapsulation layer are both made of two polyester yarns with a linear density of 200D.

[0075] The yarns used to form the first electrode layer and the yarns used to form the second electrode layer are both made of silver-plated nylon with a linear density of 280D, manufactured by Qingdao Tianyin Textile Technology Co., Ltd., and have a resistance of 2Ω / cm.

[0076] (2) Fabrication of a pressure-sensitive sensor;

[0077] Parallel composite conductive fibers and parallel composite non-conductive fibers are used as spacer yarns. Together with yarns used to form the first electrode layer, the second electrode layer, the first insulating encapsulation layer, and the second insulating encapsulation layer, a spacer fabric is woven using a double-sided weft knitting process. The spacer yarns are connected to the upper and lower layers using a two-row tuck full-needle method. After weaving to form a spacer knitted fabric structure, the spacer fabric is sent to a heat setting machine and set at 240°C for 5 minutes. This causes two adjacent parallel composite fibers (i.e., parallel composite conductive fibers and parallel composite non-conductive fibers) to adhere to each other at the spiral contact point, thus obtaining a pressure-sensitive sensor.

[0078] The final pressure-sensitive sensor consists of a first insulating encapsulation layer, a first electrode layer, a pressure-sensitive layer, a second electrode layer, and a second insulating encapsulation layer arranged sequentially from top to bottom. Both the first and second insulating encapsulation layers are plain knit weave, while both the first and second electrode layers are padded weave. The pressure-sensitive layer is composed of parallel composite conductive fibers and parallel composite non-conductive fibers, with the central axes of the parallel composite conductive fibers and parallel composite non-conductive fibers oriented along the thickness direction of the pressure-sensitive layer. The weight percentage of the parallel composite conductive fibers in the pressure-sensitive layer is 80%.

[0079] The pressure sensor has a thickness of 2.5 mm, with the pressure-sensitive layer accounting for 80% of the total thickness. After 100,000 cyclic compressions under compressive stress of 0–50 kPa, the baseline resistance change rate of the pressure sensor is 1.7%. The hysteresis error of the pressure sensor during a single loading and unloading cycle is 2%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0080]

[0081] like Figures 1-3 As shown, in the pressure-sensitive sensor prepared in this embodiment, the pressure-sensitive layer 1 is composed of helical parallel composite fibers 5. Each parallel composite fiber 5 contains a component 2 containing a non-conductive polymer with a higher shrinkage rate and a component 3 containing a non-conductive polymer with a lower shrinkage rate. The component 3 containing the non-conductive polymer with a lower shrinkage rate of the parallel composite conductive fiber also contains conductive particles. Adjacent parallel composite fibers 5 adhere to each other at their helical contact points to form adhesion points 4. Each adhesion point 4, together with the parallel composite fibers 5, forms a multi-directional interconnected continuous network structure.

[0082] Example 2

[0083] A method for fabricating a pressure-sensitive sensor, the specific steps of which are as follows:

[0084] (1) Preparation of materials;

[0085] Parallel-type composite conductive fiber: The first component's substrate is a first non-conductive polymer (PET, melting point 265℃), which is doped with conductive particles (carbon black and carbon nanotubes in a mass ratio of 9:1; the carbon black is from Orion Engineered Carbons, brand name Printex XE 2B; the carbon nanotubes are from Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, product name TNIM1), and the weight of the conductive particles is 10% of the weight of the first component; the second component's substrate is a second non-conductive polymer (PET, melting point 244℃); the shrinkage difference between the first and second non-conductive polymers is 2.48%, with the first non-conductive polymer having a smaller shrinkage rate than the second non-conductive polymer; the volume ratio of the first to the second component is 50:50; the parallel-type composite conductive fiber is helical, with a dumbbell-shaped monofilament cross-section, a monofilament diameter of 35μm, a multifilament fineness of 100dtex, a helix count of 1 / mm, a crimp radius of 0.8mm, and a resistivity of 1.8×10⁻⁶. 3 Ω / cm;

[0086] Parallel composite non-conductive fiber: The base material of the first component is a third non-conductive polymer (PET, melting point 265℃), and the base material of the second component is a fourth non-conductive polymer (PET, melting point 244℃); the shrinkage difference between the third and fourth non-conductive polymers is 4.93%, and the shrinkage rate of the third non-conductive polymer is less than that of the fourth non-conductive polymer; the volume ratio of the first component to the second component is 40:60; the parallel composite non-conductive fiber is helical, the monofilament cross-section is gourd-shaped, the monofilament diameter is 5μm, the multifilament fineness is 800dtex, the number of helices is 1.5 / mm, and the crimp radius is 0.72mm;

[0087] The first electrode layer and the second electrode layer are both plain knitted fabrics, both made of silver-plated nylon with a linear density of 280D (manufacturer: Qingdao Tianyin Textile Technology Co., Ltd., resistance: 2Ω / cm);

[0088] (2) Fabrication of a pressure-sensitive sensor;

[0089] Parallel composite conductive fibers and parallel composite non-conductive fibers are mixed and combed together. Then, a vertical web-forming technique is used to make the parallel composite conductive fibers and parallel composite non-conductive fibers stand upright to form a fiber web. The fiber web is then sent to a heat setting machine and set at 250°C for 5 minutes, so that two adjacent parallel composite fibers adhere to each other at the spiral contact point to obtain a pressure-sensitive layer. The pressure-sensitive layer is then combined with the first electrode layer and the second electrode layer by stacking or bonding to obtain a pressure-sensitive sensor.

[0090] The final pressure sensor consists of a first electrode layer, a pressure-sensitive layer, and a second electrode layer arranged from top to bottom. The pressure-sensitive layer is composed of parallel composite conductive fibers and parallel composite non-conductive fibers, with the central axes of the parallel composite conductive fibers and parallel composite non-conductive fibers oriented along the thickness direction of the pressure-sensitive layer. The weight percentage of the parallel composite conductive fibers in the pressure-sensitive layer is 60%.

[0091] The pressure sensor has a thickness of 15mm, with the pressure-sensitive layer accounting for 98% of the total thickness. After 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, the baseline resistance change rate of the pressure sensor is 1.5%. The hysteresis error of the pressure sensor during a single loading and unloading cycle is 0.6%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0092]

[0093] Example 3

[0094] A method for fabricating a pressure-sensitive sensor, the specific steps of which are as follows:

[0095] (1) Preparation of materials;

[0096] Parallel-type composite conductive fiber: The first component's substrate is a first non-conductive polymer (PET, melting point 265℃), which is doped with conductive particles (carbon black, manufactured by Orion Engineered Carbons, brand name Printex XE 2B), with the weight of the conductive particles being 0.5% of the weight of the first component; the second component's substrate is a second non-conductive polymer (PTT, melting point 215℃); the shrinkage difference between the first and second non-conductive polymers is 4.24%, with the first non-conductive polymer having a smaller shrinkage rate than the second non-conductive polymer; the volume ratio of the first to the second component is 20:80; the parallel-type composite conductive fiber is helical, with a circular cross-sectional shape for each filament, a filament diameter of 15μm, a multifilament fineness of 120dtex, a helix count of 3 / mm, a crimp radius of 0.4mm, and a resistivity of 7.8×10⁻⁶. 6 Ω / cm;

[0097] Parallel composite non-conductive fiber: The matrix of the first component is the third non-conductive polymer (PET, melting point 265℃), and the matrix of the second component is the fourth non-conductive polymer (PTT, melting point 215℃); the shrinkage difference between the third and fourth non-conductive polymers is 1.89%, and the shrinkage of the third non-conductive polymer is less than that of the fourth non-conductive polymer; the volume ratio of the first component to the second component is 40:60; the parallel composite non-conductive fiber is helical, the monofilament cross-section is circular, the monofilament diameter is 14μm, the multifilament fineness is 120dtex, the number of helices is 2.5 / mm, and the crimp radius is 0.48mm;

[0098] The yarns used to form the first electrode layer and the yarns used to form the second electrode layer are both 7×0.03mm copper stranded wires manufactured by Sanling Wire (Dongguan) Co., Ltd., with a resistance of 0.05Ω / cm.

[0099] (2) Fabrication of a pressure-sensitive sensor;

[0100] The spacer fabric is woven using a double-needle-bed warp knitting process. The warp knitting machine is equipped with six guide bars (GB1~GB6). GB1 and GB2 are fully threaded with yarns to form the first electrode layer, knitting the first electrode layer with the following yarn padding numbers: GB1: 1-0-0-0 / 3-2-3-3 / / , GB2: 2-1-1-1 / 1-0-0-0 / / . GB5 and GB6 are fully threaded with yarns to form the second electrode layer, knitting the second electrode layer with the following yarn padding numbers: GB5: 0-0-2-1 / 1-1-1-0 / / , GB6: 3-3-1-0 / 0- 0-3-2 / / ; GB3 and GB4 use a one-through-one-open yarn method, inserting parallel composite conductive fibers and parallel composite non-conductive fibers (as spacer yarns). The first electrode layer and the second electrode layer are connected by alternately padding yarns on the front and back needle beds. The padding yarn numbers are: GB3: 1-0-3-2 / 3-2-1-0 / / , GB4: 3-2-1-0 / 1-0-3-2 / / ; After weaving, the spacer fabric is sent to a heat setting machine and set at 235℃ for 5 minutes, so that the two adjacent parallel composite fibers stick together at the spiral contact point, thus obtaining the pressure sensor.

[0101] The final pressure-sensitive sensor consists of a first electrode layer, a pressure-sensitive layer, and a second electrode layer arranged from top to bottom. Both the first and second electrode layers are warp-knitted fabric layers. The pressure-sensitive layer is composed of parallel composite conductive fibers and parallel composite non-conductive fibers. The central axes of the parallel composite conductive fibers and parallel composite non-conductive fibers are oriented along the thickness direction of the pressure-sensitive layer. The weight percentage of the parallel composite conductive fibers in the pressure-sensitive layer is 66.7%.

[0102] The pressure sensor has a thickness of 10.5 mm, with the pressure-sensitive layer accounting for 82% of the total thickness. After 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, the baseline resistance change rate of the pressure sensor is 3%. The hysteresis error of the pressure sensor during a single loading and unloading cycle is 1.4%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0103]

[0104] Example 4

[0105] A method for fabricating a pressure-sensitive sensor, the specific steps of which are as follows:

[0106] (1) Preparation of materials;

[0107] Parallel-type composite conductive fiber: The first component's substrate is a first non-conductive polymer (PET, melting point 265℃), which is doped with conductive particles (graphene, manufacturer: Zhengzhou Kaichi Chemical Products Co., Ltd., product number HGP-20), with the conductive particles accounting for 8% of the weight of the first component; the second component's substrate is a second non-conductive polymer (TPEE, melting point 195℃); the shrinkage difference between the first and second non-conductive polymers is 1.92%, with the first non-conductive polymer having a smaller shrinkage rate than the second; the volume ratio of the first to the second component is 30:70; the parallel-type composite conductive fiber is helical, with a circular monofilament cross-section, a monofilament diameter of 12μm, a multifilament fineness of 220dtex, a helix count of 2.5 / mm, a crimp radius of 0.5mm, and a resistivity of 9.2×10⁻⁶. 4 Ω / cm;

[0108] Parallel composite non-conductive fiber: The matrix of the first component is a third non-conductive polymer (PET, melting point 265℃), and the matrix of the second component is a fourth non-conductive polymer (TPEE, melting point 195℃); the shrinkage difference between the third and fourth non-conductive polymers is 1.55%, and the shrinkage of the third non-conductive polymer is less than that of the fourth non-conductive polymer; the volume ratio of the first component to the second component is 40:60; the parallel composite non-conductive fiber is helical, the monofilament cross-section is circular, the monofilament diameter is 15μm, the multifilament fineness is 220dtex, the number of helices is 2 / mm, and the crimp radius is 0.63mm;

[0109] The yarns used to form the first electrode layer and the yarns used to form the second electrode layer are both 9×0.03mm copper stranded wires manufactured by Sanling Wire Manufacturing (Dongguan) Co., Ltd., with a resistance of 0.03Ω / cm.

[0110] (2) Fabrication of a pressure-sensitive sensor;

[0111] A double-layer woven spacer fabric is produced by using parallel composite conductive fibers and parallel composite non-conductive fibers as weft spacer yarns. These fibers are alternately interwoven between the warp yarns in a plain weave. At the same time, yarns for forming the first electrode layer and yarns for forming the second electrode layer are woven into the corresponding layers to form an integral spacer fabric. After weaving, the spacer fabric is sent to a heat setting machine and set at 230°C for 5 minutes, so that two adjacent parallel composite fibers adhere to each other at the spiral contact point, thus obtaining the pressure sensor.

[0112] The final pressure-sensitive sensor consists of a first electrode layer, a pressure-sensitive layer, and a second electrode layer arranged sequentially from top to bottom. Both the first and second electrode layers have a plain weave structure. The pressure-sensitive layer is composed of parallel composite conductive fibers and parallel composite non-conductive fibers. The central axes of the parallel composite conductive fibers and parallel composite non-conductive fibers are oriented along the thickness direction of the pressure-sensitive layer. The weight percentage of the parallel composite conductive fibers in the pressure-sensitive layer is 50%.

[0113] The pressure sensor has a thickness of 21 mm, with the pressure-sensitive layer accounting for 81% of the total thickness. After 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, the baseline resistance change rate of the pressure sensor is 1.8%. The hysteresis error of the pressure sensor during a single loading and unloading cycle is 1.2%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0114]

[0115] Example 5

[0116] A method for fabricating a pressure-sensitive sensor, the specific steps of which are as follows:

[0117] (1) Preparation of materials;

[0118] Parallel composite conductive fiber: The first component's substrate is a first non-conductive polymer (TPU, melting point 220℃), which is doped with conductive particles (polypyrrole, manufacturer: Sigma-Aldrich (Merck KGaA, Darmstadt, Germany), product number 577030), with the conductive particles accounting for 5% of the weight of the first component; the second component's substrate is a second non-conductive polymer (TPU, melting point 175℃); the shrinkage difference between the first and second non-conductive polymers is 5.07%, with the first non-conductive polymer having a smaller shrinkage rate than the second; the volume ratio of the first to the second component is 40:60; the parallel composite conductive fiber is helical, with a dumbbell-shaped monofilament cross-section, a monofilament diameter of 20μm, a multifilament fineness of 800dtex, a helix count of 2.5 / mm, a crimp radius of 0.58mm, and a resistance of 2.4×10⁻⁶. 3 Ω / cm;

[0119] The first insulating encapsulation layer and the second insulating encapsulation layer are both plain knitted fabrics, woven from nylon yarn with a linear density of 600D.

[0120] The first electrode layer and the second electrode layer are both plain knitted fabrics, woven from 7×0.03mm copper stranded wire (manufacturer: Sanling Wire (Dongguan) Co., Ltd., resistance: 0.05Ω / cm);

[0121] (2) Fabrication of a pressure-sensitive sensor;

[0122] After the parallel composite conductive fibers are upright and formed into a web using vertical web forming technology, the web is sent to a heat setting machine and set at 195°C for 5 minutes, so that two adjacent parallel composite conductive fibers adhere to each other at the spiral contact point to obtain a pressure-sensitive layer. Then, the pressure-sensitive layer is combined with the first electrode layer, the second electrode layer, the first insulating encapsulation layer, and the second insulating encapsulation layer by stitching to obtain a pressure-sensitive sensor.

[0123] The final pressure sensor consists of a first insulating encapsulation layer, a first electrode layer, a pressure-sensitive layer, a second electrode layer, and a second insulating encapsulation layer arranged sequentially from top to bottom; the pressure-sensitive layer is composed of parallel composite conductive fibers, with the central axis of the parallel composite conductive fibers oriented along the thickness direction of the pressure-sensitive layer;

[0124] The pressure sensor has a thickness of 33 mm, with the pressure-sensitive layer accounting for 85% of the total thickness. After 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, the baseline resistance change rate is 0.8%. The hysteresis error during a single loading and unloading cycle is 0.7%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0125]

[0126] Example 6

[0127] A method for fabricating a pressure-sensitive sensor, the specific steps of which are as follows:

[0128] (1) Preparation of materials;

[0129] Parallel-type composite conductive fiber: The first component's substrate is a first non-conductive polymer (PET, melting point 270℃), which is doped with conductive particles (MXene, manufacturer: Sisco Research Laboratories Pvt. Ltd. (SRL, India), item number 95822), with the conductive particles accounting for 3% of the weight of the first component; the second component's substrate is a second non-conductive polymer (PA66, melting point 260℃); the shrinkage difference between the first and second non-conductive polymers is 5.91%, with the first non-conductive polymer having a smaller shrinkage rate than the second; the volume ratio of the first to the second component is 10:90; the parallel-type composite conductive fiber is helical, with a circular monofilament cross-section, a monofilament diameter of 10μm, a multifilament fineness of 200dtex, a helix count of 3 / mm, a crimp radius of 0.4mm, and a resistivity of 4.5×10⁻⁶. 6 Ω / cm;

[0130] Parallel composite non-conductive fiber: The first component's matrix is ​​a third non-conductive polymer (PET, melting point 270℃), and the second component's matrix is ​​a fourth non-conductive polymer (PA66, melting point 260℃); the shrinkage difference between the third and fourth non-conductive polymers is 15.6%, with the third non-conductive polymer having a smaller shrinkage rate than the fourth non-conductive polymer; the volume ratio of the first to the second component is 5:95; the parallel composite non-conductive fiber is helical, with a circular monofilament cross-section, a monofilament diameter of 10μm, a multifilament fineness of 200dtex, a helix count of 4 / mm, and a crimp radius of 0.31mm;

[0131] The yarns used to form the first insulating encapsulation layer and the yarns used to form the second insulating encapsulation layer are both 210D spandex yarns wrapped with double layers of 100D polyester yarns.

[0132] The yarns used to form the first electrode layer and the yarns used to form the second electrode layer are both made of silver-plated nylon with a linear density of 280D, manufactured by Qingdao Tianyin Textile Technology Co., Ltd., and have a resistance of 2Ω / cm.

[0133] (2) Fabrication of a pressure-sensitive sensor;

[0134] Parallel composite conductive fibers and parallel composite non-conductive fibers are used as spacer yarns. Together with yarns used to form the first electrode layer, the second electrode layer, the first insulating encapsulation layer, and the second insulating encapsulation layer, a spacer fabric is woven using a double-sided weft knitting process. The spacer yarns are connected to the upper and lower layers using a two-row tuck full-needle method. After weaving to form a spacer knitted fabric structure, the spacer fabric is sent to a heat setting machine and set at 265°C for 5 minutes, so that two adjacent parallel composite fibers adhere to each other at the spiral contact point, thus obtaining the pressure sensor.

[0135] The final pressure-sensitive sensor consists of a first insulating encapsulation layer, a first electrode layer, a pressure-sensitive layer, a second electrode layer, and a second insulating encapsulation layer arranged sequentially from top to bottom. Both the first and second insulating encapsulation layers are of flat needle structure, and both the first and second electrode layers are of coil structure. The pressure-sensitive layer is composed of parallel composite conductive fibers and parallel composite non-conductive fibers, with the central axes of the parallel composite conductive fibers and parallel composite non-conductive fibers oriented along the thickness direction of the pressure-sensitive layer. The weight percentage of the parallel composite conductive fibers in the pressure-sensitive layer is 90%.

[0136] The pressure sensor has a thickness of 5.6 mm, with the pressure-sensitive layer accounting for 84% of the total thickness. After 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, the baseline resistance change rate of the pressure sensor is 1.5%. The hysteresis error of the pressure sensor during a single loading and unloading cycle is 1.6%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0137]

[0138] Example 7

[0139] A method for preparing a pressure-sensitive sensor differs from Example 6 only in that, in the parallel composite conductive fibers used, the first non-conductive polymer is replaced with PA66 (melting point 260°C) and the second non-conductive polymer is replaced with PET (melting point 270°C), which makes the shrinkage rate of the first non-conductive polymer greater than that of the second non-conductive polymer.

[0140] The final pressure sensor, after 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, exhibited a baseline resistance change rate of 1.4%. The single-cycle loading and unloading hysteresis error of the pressure sensor was 1.8%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0141]

[0142] Comparing Examples 6 and 7, it can be seen that when the shrinkage rate of the first non-conductive polymer is less than that of the second non-conductive polymer, the conductive particles can be distributed on the outside of the spiral fiber along with the first non-conductive polymer. The conductive particles of different parallel composite conductive fibers are more likely to come into contact, which makes it easier to cause changes in contact resistance. The pressure sensor containing this pressure-sensitive layer will have higher sensitivity.

[0143] Example 8

[0144] The only difference between the method for preparing a pressure-sensitive sensor and Example 6 is that the volume ratio of the first component to the second component in the parallel composite conductive fiber used is 20:80, which makes the number of spirals of the parallel composite conductive fiber 2.5 / mm.

[0145] The final pressure sensor, after 100,000 cyclic compressions under compressive stresses ranging from 0 to 50 kPa, exhibited a baseline resistance change rate of 4.2%. The single-cycle loading and unloading hysteresis error of the pressure sensor was 3.7%. The relative resistance changes of the pressure sensor under various load levels are shown in the table below.

[0146]

[0147] Comparing Examples 6 and 8, it can be seen that a suitable difference in the number of spirals can ensure the effective contact probability of the exposed contact surface of the conductive particles, thereby improving the sensitivity, cycle stability and measurement accuracy of the pressure sensor.

Claims

1. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure, characterized in that, It is composed of parallel composite fibers, including parallel composite conductive fibers; The parallel composite conductive fibers are spiral-shaped, with their central axis oriented along the thickness direction of the pressure-sensitive layer; The two components in the parallel composite conductive fiber are referred to as the first component and the second component, respectively. Only the first component contains conductive particles. The substrate of the first component is the first non-conductive polymer, and the substrate of the second component is the second non-conductive polymer. Adjacent parallel composite fibers adhere to each other at the helical contact points, forming a multi-directional interconnected continuous network structure.

2. The pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 1, characterized in that, The shrinkage rate of the first non-conductive polymer is less than that of the second non-conductive polymer.

3. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 1, characterized in that, The shrinkage difference between the first non-conductive polymer and the second non-conductive polymer is 1.92% to 8.88%.

4. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 1, characterized in that, The first non-conductive polymer and the second non-conductive polymer have different melting temperatures, with a difference of 10~70℃.

5. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 1, characterized in that, The conductive particles are one or more of carbon black, carbon nanotubes, graphene / graphite, MXene, and conductive polymers; in the first component of the parallel composite conductive fiber, the weight percentage of conductive particles is 0.5%~10%; the resistance of the parallel composite conductive fiber is 10 ohms. 3 ~7.8×10 6 Ω / cm.

6. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 1, characterized in that, Two adjacent parallel composite fibers are bonded together at the helical contact point by heat setting.

7. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 1, characterized in that, Parallel composite fibers also include parallel composite non-conductive fibers; The parallel composite non-conductive fibers are spiral-shaped, with their central axis oriented along the thickness direction of the pressure-sensitive layer; The two components in the parallel composite non-conductive fiber are referred to as the first component and the second component, respectively. The substrate of the first component is the third non-conductive polymer, and the substrate of the second component is the fourth non-conductive polymer.

8. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 7, characterized in that, The shrinkage difference between the third and fourth non-conductive polymers is 1.55% to 15.6%.

9. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 7, characterized in that, The third non-conductive polymer and the fourth non-conductive polymer have different melting temperatures, with a difference of 10~70℃.

10. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 7, characterized in that, The first to fourth non-conductive polymers are each independently selected from one or more of polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyamide, polyester thermoplastic elastomers, and polyurethane elastomers.

11. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 7, characterized in that, The difference in the number of spirals between parallel composite conductive fibers and parallel composite non-conductive fibers is 0.5 to 1 spiral / mm.

12. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 7, characterized in that, The diameter of the monofilament of the parallel composite conductive fiber is 10~35μm, and the fineness of the multifilament is 100~800dtex; the diameter of the monofilament of the parallel composite non-conductive fiber is 5~15μm, and the fineness of the multifilament is 100~800dtex; the cross-sectional shape of the monofilament of the parallel composite conductive fiber or the parallel composite non-conductive fiber is circular, dumbbell-shaped or gourd-shaped.

13. A pressure-sensitive layer based on a multi-directional interconnected continuous network structure according to claim 7, characterized in that, In the pressure-sensitive layer, the weight percentage of parallel composite conductive fibers is 50% to 100%; in the parallel composite conductive fibers or parallel composite non-conductive fibers, the volume ratio of the first component to the second component is 5:95 to 50:

50.

14. A pressure-sensitive sensor, comprising a pressure-sensitive layer and other functional layers, wherein the other functional layers include a first electrode layer and a second electrode layer, the first electrode layer, the pressure-sensitive layer, and the second electrode layer are arranged sequentially from top to bottom, characterized in that, The pressure-sensitive layer is a pressure-sensitive layer based on a multi-directional interconnected continuous network structure as described in any one of claims 1 to 13.

15. A pressure-sensitive sensor according to claim 14, characterized in that, Other functional layers include a first insulating encapsulation layer and a second insulating encapsulation layer. The first insulating encapsulation layer is located above and adjacent to the first electrode layer, and the second insulating encapsulation layer is located below and adjacent to the second electrode layer.

16. A pressure-sensitive sensor according to claim 14 or 15, characterized in that, The thickness of the pressure sensor is 2.5~33mm, and the thickness of the pressure-sensitive layer accounts for 80%~98%; the pressure sensor is cyclically compressed 100,000 times under compressive stress of 0~50kPa, and the baseline resistance change rate is ≤4.2%; the hysteresis error of the pressure sensor during a single loading and unloading is ≤3.7%.

17. A method for preparing a pressure-sensitive sensor as described in any one of claims 14-16, characterized in that, By using parallel composite fibers as spacer yarns and weaving them together with yarns used to form other functional layers to create a spacer fabric, the spacer fabric is then treated so that adjacent parallel composite fibers adhere to each other at the helical contact point, thus obtaining a pressure-sensitive sensor.

18. A method for preparing a pressure-sensitive sensor as described in any one of claims 14-16, characterized in that, After the parallel composite fibers are formed upright using vertical web forming technology, they are processed so that two adjacent parallel composite fibers adhere to each other at the spiral contact point to obtain a pressure-sensitive layer. The pressure-sensitive layer is then combined with other functional layers to form a pressure-sensitive sensor.

Images