Preparation method of flexible pressure-sensitive fiber fabric and flexible pressure-sensitive fiber fabric sensor

Abstract

The invention relates to the technical field of sensitive element and sensor manufacturing and the like, and provides a preparation method of a flexible pressure-sensitive fiber fabric and a flexible pressure-sensitive fiber fabric sensor.The preparation method comprises the steps that a conductive material is prepared, carbon, carbon nanotubes, carbon graphene and silver powder are evenly mixed according to a preset proportion, and the conductive material is obtained; the preparation method comprises the following steps: preparing a mixed material of a conductive material and a matrix material, uniformly mixing the conductive material and the matrix material of polyester and nylon in a planetary high-speed stirrer to obtain the mixed material of the conductive material and the matrix material, and preparing conductive fibers and fabrics, according to the flexible pressure-sensitive fabric, the mixed material of the conductive material and the base material is prepared into the conductive fibers with the preset fineness, and then the conductive fibers with the preset fineness are woven into the piezoresistive pressure-sensitive fabric through a tatting or knitting process, so that the mechanical strength, the friction resistance and the conductive dispersion uniformity of the flexible pressure-sensitive fabric are improved, and the voltage stability is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical fields such as the manufacture of sensitive components and sensors, and particularly relates to a preparation method of a flexible pressure-sensitive fiber fabric and a flexible pressure-sensitive fiber fabric sensor. Background Art

[0002] Flexible pressure-sensitive fiber fabric sensors have a wide range of application fields. For example, they can be used in fields such as mattresses, pillows, car seats, smart wearables, humanoid robots, etc. In the production process of flexible pressure-sensitive fiber fabric sensors, flexible pressure-sensitive fiber fabrics are required. In the prior art, flexible pressure-sensitive fiber fabrics have always had unstable voltages, and are prone to resistance attenuation due to factors such as washing, pressing, and friction, forming a persistent resistance network, which ultimately affects the working performance of flexible pressure-sensitive fiber fabric sensors.

[0003] In summary, the existing production technologies of flexible pressure-sensitive fiber fabric sensors have technical problems such as unstable voltages of flexible pressure-sensitive fiber fabrics and the working performance of flexible pressure-sensitive fiber fabric sensors being easily adversely affected. Summary of the Invention

[0004] Aiming at the deficiencies of the above-mentioned prior art, the present invention provides a preparation method of a flexible pressure-sensitive fiber fabric and a flexible pressure-sensitive fiber fabric sensor to improve the mechanical strength, anti-friction property, and uniform dispersion of conductivity of the flexible pressure-sensitive fiber fabric and ensure voltage stability.

[0005] In the first aspect, the present invention provides a preparation method of a flexible pressure-sensitive fiber fabric, including: Preparing a conductive material by uniformly mixing carbon, carbon nanotubes, carbon graphene, and silver powder in a predetermined ratio to obtain the conductive material; Preparing a mixed material of the conductive material and a matrix material by uniformly mixing the conductive material with matrix materials of polyester and nylon in a planetary high-speed mixer to obtain the mixed material of the conductive material and the matrix material; Preparing conductive fiber filaments and a fabric by preparing the mixed material of the conductive material and the matrix material into conductive fiber filaments with a preset fineness, and then weaving the conductive fiber filaments with a preset fineness into a piezoresistive pressure-sensitive fabric through a weaving or knitting process.

[0006] In the second aspect, the present invention provides a flexible pressure-sensitive fiber fabric sensor, including: An upper electrode substrate, which is prepared from a fabric or leather and is used to provide mechanical support and surface protection, enabling the sensor to be sewn to the sensor usage terminal; The upper electrode trace layer is sewn onto the upper electrode substrate using stainless steel wires, carbon fiber wires, or silver fiber wires to form a longitudinal or transverse electrode grid on the upper electrode substrate. The end of the upper electrode trace layer forms a clamping terminal that clamps onto the upper electrode substrate; The upper intensifying conductive fabric layer covers the longitudinal or transverse electrode grid formed by the upper electrode trace layer on the upper electrode substrate to expand the induction area of the electrode grid; The flexible pressure-sensitive fiber fabric layer is made of a flexible pressure-sensitive fiber fabric, and the flexible pressure-sensitive fiber fabric is prepared using the preparation method of the above flexible pressure-sensitive fiber fabric; The lower electrode substrate is prepared from cloth or leather to provide mechanical support and surface protection, enabling the sensor to be sewn onto the sensor usage terminal; The lower electrode trace layer is sewn onto the lower electrode substrate using stainless steel wires, carbon fiber wires, or silver fiber wires to form a longitudinal or transverse electrode grid on the lower electrode substrate. The end of the lower electrode trace layer forms a clamping terminal that clamps onto the lower electrode substrate; the longitudinal or transverse electrode grid formed on the lower electrode substrate is perpendicular to the longitudinal or transverse electrode grid formed on the upper electrode substrate; The lower intensifying conductive fabric layer covers the longitudinal or transverse electrode grid formed by the lower electrode trace layer on the lower electrode substrate to expand the induction area of the electrode grid; Wherein, the upper side of the flexible pressure-sensitive fiber fabric layer covers the upper intensifying conductive fabric layer, the upper electrode trace layer, and the upper electrode substrate, and the lower side of the flexible pressure-sensitive fiber fabric layer covers the lower intensifying conductive fabric layer, the lower electrode trace layer, and the lower electrode substrate.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a preparation method of a flexible pressure-sensitive fiber fabric and a flexible pressure-sensitive fiber fabric sensor. By preparing a conductive material, carbon, carbon nanotubes, carbon graphene, and silver powder are uniformly mixed in a predetermined ratio to obtain the conductive material. A mixed material of the conductive material and a matrix material is prepared by uniformly mixing the conductive material with a matrix material of polyester and nylon in a planetary high-speed mixer to obtain a mixed material of the conductive material and the matrix material. Conductive fiber filaments and fabrics are prepared by preparing the mixed material of the conductive material and the matrix material into conductive fiber filaments of a preset fineness, and then weaving the conductive fiber filaments of the preset fineness into a piezoresistive pressure-sensitive fabric through a weaving or knitting process, thereby improving the mechanical strength, anti-friction property, and conductive dispersion uniformity of the flexible pressure-sensitive fiber fabric and ensuring voltage stability. Description of the Drawings

[0008] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Some specific embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings in an exemplary rather than restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 is a schematic flow chart of a method for preparing a flexible pressure-sensitive fiber fabric according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of a pressure-sensitive fiber fabric sensor according to an embodiment of the present invention. Detailed Embodiments

[0009] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0010] Embodiment 1 Refer to Figure 1 - Figure 2 , this embodiment provides a method for preparing a flexible pressure-sensitive fiber fabric, including the following steps: S101. Prepare a conductive material by uniformly mixing carbon, carbon nanotubes, carbon graphene, and silver powder in a predetermined ratio to obtain the conductive material; S102. Prepare a mixed material of the conductive material and the matrix material by uniformly mixing the conductive material with the matrix materials of polyester and nylon in a planetary high-speed mixer to obtain a mixed material of the conductive material and the matrix material; S103. Prepare conductive fiber filaments and a fabric by forming the mixed material of the conductive material and the matrix material into conductive fiber filaments with a preset fineness, and then weaving the conductive fiber filaments with a preset fineness into a piezoresistive pressure-sensitive fabric through a weaving or knitting process.

[0011] The following table shows the performance indexes of the flexible pressure-sensitive fiber fabric in this embodiment, such as mechanical strength, anti-friction ability, conductive dispersion uniformity, voltage resistance performance, and creep performance.

[0012]

[0013] In the table, the mechanical strength of the flexible pressure-sensitive fiber fabric was tested by methods such as three-point bending test (ASTM D790) and nanoindentation test, and the experimental data obtained were: Young's modulus ≥ 50 MPa, fracture strength ≥ 50 MPa. The anti-friction ability of the flexible pressure-sensitive fiber fabric was tested by methods such as reciprocating friction test (ISO 9352) and cyclic loading test, and the experimental data obtained were that the resistance change was ≤ 5% and the surface roughness change was ≤ 5% after 100,000 cycles. The anti-friction ability of the flexible pressure-sensitive fiber fabric was tested by methods such as reciprocating friction test (ISO 9352) and cyclic loading test, and the experimental data obtained were that the resistance change was ≤ 5% and the surface roughness change was ≤ 5% after 100,000 cycles. The conductive dispersion uniformity of the flexible pressure-sensitive fiber fabric was tested by methods such as SEM image analysis and resistance distribution statistics, and the experimental data obtained were that the standard deviation of particle size distribution was ≤ 5% and the resistance fluctuation was ≤ 3%. The pressure resistance performance of the flexible pressure-sensitive fiber fabric was tested by methods such as stepped pressure loading test (ISO 22817) and overload impact test, and the experimental data obtained were that the working pressure covered 0 - 500 kPa and the overload capacity was greater than or equal to 300% FS. The creep performance of the flexible pressure-sensitive fiber fabric was tested by methods such as static loading stability test (ISO 8013) and long-term aging test, and the experimental data obtained were that the drift was ≤ 0.1% FS in 24 hours and ≤ 0.1% FS annually. Herein, FS (Full-Scale) represents the maximum output value within the range of the measuring range.

[0014] It should be noted that in this embodiment, a composite system of carbon, carbon nanotubes, carbon graphene, and silver powder is adopted, and high conductivity and stability are achieved through multi-component synergy (carbon nanotubes provide a conductive network, silver powder reduces the contact resistance, and graphene enhances the mechanical strength). Polyester and nylon are used as the matrix, which have both flexibility and wear resistance, and can be processed by textile processes after being blended with conductive materials to ensure the weavability of the fabric. The planetary high-speed mixer ensures uniform dispersion, and the subsequent spinning and weaving processes (woven / knitted) form a stable resistance network structure, reducing the resistance attenuation caused by friction and washing at the source. In this embodiment, the preparation method of the flexible pressure-sensitive fiber fabric directly improves the mechanical strength (Young's modulus ≥ 50 MPa) and anti-friction property (resistance change ≤ 5% after 100,000 cycles) through the synergistic optimization of the material formula and process, and at the same time, the conductive dispersion uniformity (resistance fluctuation ≤ 3%) ensures the voltage stability.

[0015] In some preferred embodiments, when preparing the conductive fiber filaments, it includes: preparing a mixed material of the conductive material and the matrix material by a co-blending spinning method and a special composite spinning process to form conductive fiber filaments with a fineness of 20D - 200D. It should be noted that the fiber filaments with a fineness of 20D - 200D can ensure sufficient mechanical strength (avoiding easy breakage due to being too thin) and are also suitable for textile processes (being too thick affects the flexibility of the fabric). The co-blending spinning method ensures the uniform dispersion of the conductive material in the matrix; the special composite spinning (such as a core-shell structure) can further protect the conductive network and reduce external friction damage. In this embodiment, through the coordinated control of fineness and process, the fiber filaments can have both high conductivity (single-filament resistivity from 10 -2 Ω·cm to 10 2 Ω·cm) and processability.

[0016] In some preferred embodiments, when preparing the mixed material of the conductive material and the matrix material, the mass of the conductive material accounts for 3% - 20% of the mass of the matrix material. It should be noted that the lower limit of 3% of the mass of the conductive material accounting for the mass of the matrix material can ensure the formation of a continuous conductive path, and below this value, the conductivity drops sharply. The upper limit of 20% of the mass of the conductive material accounting for the mass of the matrix material can avoid the decrease in the flexibility of the matrix or the difficulty in spinning caused by excessive conductive material. Within this range, the fabric can not only meet the sensitivity requirements (working pressure 0 - 500 kPa) but also maintain the mechanical properties of the matrix (elongation at break 20% - 40%).

[0017] In some preferred embodiments, when mixing the conductive material with the matrix material, it includes: subjecting carbon nanotubes to silanization treatment using silane coupling agent KH550, and through the condensation reaction of silane coupling agent KH550 with the hydroxylated surface of carbon nanotubes to improve the interfacial bonding force between carbon nanotubes and the matrix material. It should be noted that the condensation reaction of silane coupling agent KH550 with hydroxylated carbon nanotubes to improve the interfacial bonding force between carbon nanotubes and the matrix material can reduce the shedding of conductive particles, directly improving the anti-friction property (surface roughness change ≤ 5% after 100,000 cycles) and long-term stability (annual drift ≤ 0.1% FS).

[0018] In some preferred embodiments, after subjecting the carbon nanotubes to silanization treatment, a non-thickening surfactant is added. The non-thickening surfactant is a polyoxyethylene ether compound, and the polyoxyethylene ether compound is used to reduce the van der Waals force between carbon nanotubes to improve the uniformity of the dispersion of conductive particles in the fabric. It should be noted that after subjecting the carbon nanotubes to silanization treatment and adding a non-thickening surfactant, the van der Waals force between carbon nanotubes can be reduced, preventing agglomeration and improving the dispersion uniformity. On the basis of silanization treatment, the uniformity of the conductive network is further optimized (standard deviation of SEM particle size distribution ≤ 5%).

[0019] In some preferred embodiments, Griltex carbon nanotubes or carbon fiber dispersant D1556A is added as the main dispersant in the mixture containing polyoxyethylene ether compounds to improve the dispersion effect of carbon nanotubes and carbon fibers in the conductive material and prevent the agglomeration of the conductive material during long-term use. After adding Griltex carbon nanotubes or carbon fiber dispersant D1556A as the main dispersant, a physical dispersion process combining ultrasonic dispersion and air jet milling is implemented on the mixture of the conductive material and the matrix material to improve the uniform dispersion effect of the conductive material. Among them, the ultrasonic frequency used for ultrasonic dispersion is controlled at 20 - 40 kHz, and the dispersion time is 30 - 60 min. It should be noted that adding Griltex carbon nanotubes or carbon fiber dispersant D1556A as the main dispersant in the mixture containing polyoxyethylene ether compounds can prevent the agglomeration of carbon nanotubes or carbon fibers during long-term use and avoid resistance drift. Collaborating with the physical dispersion process, it ensures the long-term stability of the conductive material in the matrix (drift ≤ 0.1% FS in 24 hours). In this embodiment, through the scheme of ultrasonic dispersion (20 - 40 kHz, 30 - 60 min) combined with air jet milling, the ultrasonic cavitation effect is used to break the agglomerates, and the air jet milling is used to refine the particles, double guaranteeing the dispersion uniformity, achieving a resistance fluctuation ≤ 3% and an overload capacity ≥ 300% FS.

[0020] In some preferred embodiments, the mass ratio range of each component in the conductive material is specifically: carbon 10% - 40%, carbon nanotubes 20% - 50%, carbon graphene 5% - 25%, and silver powder 5% - 35%. It should be noted that carbon (10% - 40%) is used as a low-cost filler; carbon nanotubes (20% - 50%) serve as the main conductive channels; graphene (5% - 25%) is used to enhance mechanical strength; and silver powder (5% - 35%) is used to reduce the contact resistance. In this embodiment, by setting the mass ratio range of each component in the conductive material as carbon 10% - 40%, carbon nanotubes 20% - 50%, carbon graphene 5% - 25%, and silver powder 5% - 35%, the cost and performance can be balanced to achieve high sensitivity (0 - 500 kPa pressure response) and stability (creep performance meets the standard).

[0021] In some preferred embodiments, in the matrix materials of polyester and nylon, the mass ratio of polyester to nylon is 1:1 to 1:4. It should be noted that polyester provides dimensional stability and wear resistance, while nylon provides polar groups to enhance the affinity of the filler. When the proportion of nylon is too low, the flexibility is insufficient and cracks are likely to occur; when it is too high, the hygrothermal shrinkage rate increases. The mass ratio of polyester to nylon in the range of 1:1 to 1:4 can make the length of the fiber change slightly after wet-dry cycling while maintaining good breaking strength.

[0022] In some preferred embodiments, in the co - blending spinning method and the special composite spinning process, the aperture of the spinneret used is 0.1 mm - 0.5 mm, and the spinning speed is controlled at 1000 - 2000 m / min to ensure that the prepared conductive fiber filaments have a uniform diameter and stable conductive performance. It should be noted that the aperture of the spinneret being 0.1 mm - 0.5 mm can prevent the melt containing fillers from being blocked due to too small an aperture, and at the same time is conducive to melt drawing to form a uniform cross - section; the high drawing tension with the spinning speed controlled at 1000 - 2000 m / min can make the conductive fillers oriented along the axial direction, reduce the resistance jump at the transverse fracture surface, and ensure that the modulus fluctuation in the nano - indentation test is small.

[0023] In some preferred embodiments, the woven or knitted process adopts a plain or twill weave method. The weft density of the conductive fiber filaments is controlled at 40 - 80 per inch, and the warp density is controlled at 60 - 120 per inch to ensure that the flexible pressure - sensitive fabric has a uniform resistance network structure. It should be noted that the plain or twill weave can take into account both softness and stability. Controlling the weft density of the conductive fiber filaments at 40 - 80 per inch and the warp density at 60 - 120 per inch can give enough deformation space to the pressure - sensitive layer when preparing the flexible pressure - sensitive fiber fabric sensor, and at the same time ensure that the electrode contact coverage is large enough.

[0024] In some preferred embodiments, after the flexible pressure - sensitive fabric is woven, it is subjected to a post - finishing process. The post - finishing process includes heat - setting treatment and waterproof and anti - staining treatment. Among them, the heat - setting temperature is 120 - 180 °C, and the setting time is 15 - 45 min. It should be noted that with the heat - setting temperature being 120 - 180 °C and the setting time being 15 - 45 min, textile residual stress can be eliminated and the size can be locked. The waterproof and anti - staining treatment can prevent water vapor and ions from infiltrating into the network of the flexible pressure - sensitive fabric during washing and increasing the resistance.

[0025] In some preferred embodiments, the waterproof and anti - staining treatment is carried out by impregnation with a fluorocarbon - based waterproof agent. The concentration of the waterproof agent is 1% - 5%, the impregnation temperature is controlled at 50 - 80 °C, and the time is 10 - 30 min to improve the protective performance and environmental adaptability of the fabric. It should be noted that under the conditions of the waterproof agent concentration being 1% - 5%, the impregnation temperature being controlled at 50 - 80 °C, and the time being 10 - 30 min, a dense and low - energy film layer can be formed on the fiber surface, but still maintain breathability, avoiding blocking pores at too high a concentration and reducing sensitivity, and avoiding incomplete film formation at too low a temperature.

[0026] In some preferred embodiments, the resistivity of the single - filament of the conductive fiber filament is controlled at 10 -2 Ω·cm to 10 2Between 10 -2 Ω·cm and 10 2 Ω·cm to meet the high sensitivity and high stability required for the flexible pressure-sensitive fabric sensor. The tensile strength of the conductive fiber filament is controlled between 400 - 800 MPa, and the elongation at break is 20% - 40% to improve the service life and stability of the fabric in a complex mechanical environment. It should be noted that the resistivity of the single filament of the conductive fiber filament is controlled at 10

[0027] Example Two See Figure 1 - Figure 2 , this example provides a flexible pressure-sensitive fiber fabric sensor, including: Upper electrode substrate 1, which is prepared from fabric or leather, used to provide mechanical support and surface protection so that the sensor can be sewn to the sensor usage terminal; Upper electrode trace layer 2, sewn onto the upper electrode substrate using stainless steel wire, carbon fiber wire or silver fiber wire to form a longitudinal or transverse electrode grid on the upper electrode substrate. The end of the upper electrode trace layer forms a bite terminal that bites with the upper electrode substrate; Upper enhanced conductive fabric layer 3, which covers the longitudinal or transverse electrode grid formed by the upper electrode trace layer on the upper electrode substrate to expand the sensing area of the electrode grid; Flexible pressure-sensitive fiber fabric layer 4, which is made of a flexible pressure-sensitive fiber fabric, and the flexible pressure-sensitive fiber fabric is prepared by the preparation method of the flexible pressure-sensitive fiber fabric described in any one of the above embodiments; Lower electrode substrate 5, which is prepared from fabric or leather, used to provide mechanical support and surface protection so that the sensor can be sewn to the sensor usage terminal; Lower electrode trace layer 6, sewn onto the lower electrode substrate using stainless steel wire, carbon fiber wire or silver fiber wire to form a longitudinal or transverse electrode grid on the lower electrode substrate. The end of the lower electrode trace layer forms a bite terminal that bites with the lower electrode substrate; the longitudinal or transverse electrode grid formed on the lower electrode substrate is perpendicular to the longitudinal or transverse electrode grid formed on the upper electrode substrate; Lower enhanced conductive fabric layer 7, which covers the longitudinal or transverse electrode grid formed by the lower electrode trace layer on the lower electrode substrate to expand the sensing area of the electrode grid; Among them, the upper side of the flexible pressure-sensitive fiber fabric layer covers the upper sensitizing conductive fabric layer, the upper electrode trace layer, and the upper electrode substrate, and the lower side of the flexible pressure-sensitive fiber fabric layer covers the lower sensitizing conductive fabric layer, the lower electrode trace layer, and the lower electrode substrate.

[0028] It should be noted that in this embodiment, the multi-layer sandwich structure of the flexible piezoresistive fiber fabric sensor can solve technical problems such as unstable voltage, easy attenuation of the piezoresistive network, and short service life of the flexible piezoresistive fiber fabric sensor. First of all, both the upper and lower electrode substrates are selected as fabrics or leathers, which can be sewn and bent. Their flexible buffering effect can disperse macroscopic stresses when the sensor is folded, bent or washed at the usage end, avoiding the direct action of concentrated strain on the conductive circuit, and reducing the probability of electrode wire breakage and resistance mutation at the source. Secondly, the electrode wiring layer uses disk-embroidered stainless steel wires, carbon fiber wires or silver fiber wires instead of traditional copper foils or printed silver pastes: stainless steel wires, carbon fiber wires or silver fiber wires themselves are antioxidant and resistant to corrosion by sweat and washing liquids; the disk embroidery makes the metal wires in a state of winding and embedding with the substrate fibers, and its draw strength is higher than that of ordinary stitches, and it can withstand millions of bending and stretching cycles, thus solving the problem of the drift of the electrode contact resistance over time. The superimposed enhanced conductive fabric layer expands the point contact into a surface contact. On the one hand, it significantly reduces the interface contact impedance. On the other hand, it forms a soft buffer pad to absorb microscopic friction energy, inhibits fiber powdering or filler migration caused by repeated compression, and delays the curing of the permanent resistance network. The flexible piezoresistive fiber fabric layer is symmetrically coated by the upper and lower enhanced layers in the sandwich, which can avoid resistance drift caused by unilateral friction and wear. The upper and lower electrode grids are arranged orthogonally at 90°, which is convenient for matrix row-column scanning to obtain two-dimensional pressure distribution, and at the same time ensures that the area of each sensing unit is the same, reducing the output non-uniformity. In addition, terminal biting replaces stitch welding, which can improve the number of external plug-ins and long-term reliability. As shown in the above table, the performance indicators such as the mechanical strength, anti-friction ability, conductive dispersion uniformity, pressure resistance performance, and creep performance of the flexible piezoresistive fiber fabric in this embodiment are shown. Among them, the mechanical strength of the flexible piezoresistive fiber fabric is tested by methods such as three-point bending test (ASTM D790) and nanoindentation test, and the experimental data obtained are: Young's modulus ≥ 50 MPa, fracture strength ≥ 50 MPa. The anti-friction ability of the flexible piezoresistive fiber fabric is tested by methods such as reciprocating friction test (ISO9352) and cyclic loading test, and the experimental data obtained are that the resistance change ≤ 5% and the surface roughness change ≤ 5% after 100,000 cycles. The anti-friction ability of the flexible piezoresistive fiber fabric is tested by methods such as reciprocating friction test (ISO 9352) and cyclic loading test, and the experimental data obtained are that the resistance change ≤ 5% and the surface roughness change ≤ 5% after 100,000 cycles. The conductive dispersion uniformity of the flexible piezoresistive fiber fabric is tested by methods such as SEM image analysis and resistance distribution statistics, and the experimental data obtained are that the standard deviation of the particle size distribution ≤ 5% and the resistance fluctuation ≤ 3%. The pressure resistance performance of the flexible piezoresistive fiber fabric is tested by methods such as stepped pressure loading test (ISO 22817) and overload impact test, and the experimental data obtained are that the working pressure covers 0 - 500 kPa and the overload capacity is greater than or equal to 300% FS.The creep performance of the flexible pressure-sensitive fiber fabric is tested by methods such as static loading stability test (ISO 8013) and long-term aging test. The experimental data obtained are that the drift within 24 hours is less than or equal to 0.1% FS, and the annual drift is less than or equal to 0.1% FS. Among them, FS (Full-Scale) represents the maximum output value within the range. In this embodiment, a composite system of carbon, carbon nanotubes, carbon graphene and silver powder is adopted, and high conductivity and stability are achieved through multi-component synergy (carbon nanotubes provide a conductive network, silver powder reduces the contact resistance, and graphene enhances the mechanical strength). Polyester and nylon are used as the matrix, which have both flexibility and wear resistance. After being blended with the conductive material, they can be processed by textile processes to ensure the weavability of the fabric. The planetary high-speed mixer ensures uniform dispersion. The subsequent spinning and weaving processes (woven / knitted) form a stable resistance network structure, reducing the resistance attenuation caused by friction and washing from the root. In this embodiment, the preparation method of the flexible pressure-sensitive fiber fabric directly improves the mechanical strength (Young's modulus ≥ 50 MPa) and anti-friction property (resistance change ≤ 5% after 100,000 cycles) through the synergistic optimization of the material formula and process. At the same time, the uniform conductive dispersion (resistance fluctuation ≤ 3%) ensures the voltage stability.

[0029] It should be noted that the above embodiments are only preferred specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. The protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation method of a flexible pressure-sensitive fiber fabric, characterized in that, Including: Preparing a conductive material by uniformly mixing carbon, carbon nanotubes, graphene, and silver powder in a predetermined ratio to obtain the conductive material; Preparing a mixed material of the conductive material and a matrix material by uniformly mixing the conductive material with a matrix material of polyester and nylon in a planetary high-speed mixer to obtain the mixed material of the conductive material and the matrix material; Preparing a conductive fiber filament and a fabric by forming the mixed material of the conductive material and the matrix material into a conductive fiber filament with a preset fineness, and then weaving the conductive fiber filament with a fineness of 20D - 200D into a piezoresistive pressure-sensitive fabric through a weaving or knitting process.

2. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 1, characterized in that When preparing the conductive fiber filament, it includes: forming the mixed material of the conductive material and the matrix material into a conductive fiber filament with a fineness of 20D - 200D through a co-blending spinning method and a special composite spinning process.

3. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 1, characterized in that, When preparing the mixed material of the conductive material and the matrix material, the mass of the conductive material accounts for 3% - 20% of the mass of the matrix material.

4. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 1, characterized in that, When mixing the conductive material with the matrix material, it includes: subjecting the carbon nanotubes to silanization treatment with a silane coupling agent KH550, and condensing the silane coupling agent KH550 with the hydroxylated surface of the carbon nanotubes to improve the interfacial bonding force between the carbon nanotubes and the matrix material.

5. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 4, characterized in that, After the silanization treatment of the carbon nanotubes, a non-thickening surfactant is added. The non-thickening surfactant is a polyoxyethylene ether compound, and the polyoxyethylene ether compound is used to reduce the van der Waals force between the carbon nanotubes to improve the uniformity of the dispersion of conductive particles in the fabric.

6. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 5, wherein, Adding Griltex carbon nanotubes or carbon fiber dispersant D1556A as the main dispersant to the mixture containing the polyoxyethylene ether compound to improve the dispersion effect of carbon nanotubes and carbon fibers in the conductive material and prevent agglomeration of the conductive material during long-term use.

7. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 5, wherein, After adding Griltex carbon nanotubes or carbon fiber dispersant D1556A as the main dispersant, a physical dispersion process combining ultrasonic dispersion and airflow pulverization is performed on the mixed material of the conductive material and the matrix material to improve the uniform dispersion effect of the conductive material.

8. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 7, characterized in that, The ultrasonic frequency used for ultrasonic dispersion is controlled within 20 - 40 kHz, and the dispersion time is 30 - 60 min.

9. The preparation method of the flexible pressure-sensitive fiber fabric according to any one of claims 1-8, characterized in that, The specific mass ratio range of each component in the conductive material is: carbon 10% - 40%, carbon nanotubes 20% - 50%, graphene 5% - 25%, and silver powder 5% - 35%.

10. A flexible pressure-sensitive fiber fabric sensor, characterized in that, Including: An upper electrode substrate, which is prepared from fabric or leather and is used to provide mechanical support and surface protection so that the sensor can be sewn to the sensor usage terminal; An upper electrode wiring layer, which is sewn onto the upper electrode substrate with stainless steel wire, carbon fiber wire, or silver fiber wire to form a longitudinal or transverse electrode grid on the upper electrode substrate, and the end of the upper electrode wiring layer forms a biting terminal to bite with the upper electrode substrate; An upper sensitivity-enhancing conductive fabric layer, which covers the longitudinal or transverse electrode grid formed by the upper electrode wiring layer on the upper electrode substrate to expand the sensing area of the electrode grid; Flexible pressure-sensitive fiber fabric layer, which is made of flexible pressure-sensitive fiber fabric, and the flexible pressure-sensitive fiber fabric is prepared by using the preparation method of the flexible pressure-sensitive fiber fabric according to any one of claims 1-9; Lower electrode substrate, which is prepared from fabric or leather and is used to provide mechanical support and surface protection so that the sensor can be sewn to the sensor usage terminal; Lower electrode wiring layer, which is sewn onto the lower electrode substrate with stainless steel wire, carbon fiber wire or silver fiber wire to form a longitudinal or transverse electrode grid on the lower electrode substrate, and the end of the lower electrode wiring layer forms a bite terminal to bite with the lower electrode substrate; the longitudinal or transverse electrode grid formed on the lower electrode substrate is perpendicular to the longitudinal or transverse electrode grid formed on the upper electrode substrate; Lower enhancement conductive fabric layer, which covers the longitudinal or transverse electrode grid formed by the lower electrode wiring layer on the lower electrode substrate to expand the induction area of the electrode grid; Wherein, the upper side of the flexible pressure-sensitive fiber fabric layer covers the upper enhancement conductive fabric layer, the upper electrode wiring layer and the upper electrode substrate, and the lower side of the flexible pressure-sensitive fiber fabric layer covers the lower enhancement conductive fabric layer, the lower electrode wiring layer and the lower electrode substrate.

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