Preparation Method of Flexible Pressure-Sensitive Fiber Fabric and Flexible Pressure-Sensitive Fiber Fabric Sensor

Abstract

The present invention relates to the technical fields of manufacturing of sensitive components and sensors, etc., and 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 mixed evenly in a predetermined ratio to obtain the conductive material. A mixed material of the conductive material and a matrix material is prepared, and the conductive material is mixed evenly with the 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. Conductive fiber filaments and fabrics are prepared. The mixed material of the conductive material and the matrix material is prepared into conductive fiber filaments with a preset fineness, and then the conductive fiber filaments with the preset fineness are woven 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

Technical Field

[0001] The present invention relates to the technical fields of manufacturing 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, and humanoid robots. 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 suffered from unstable voltage, 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 technology of flexible pressure-sensitive fiber fabric sensors has technical problems such as unstable voltage 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] In view of the above deficiencies in the 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 a first aspect, the present invention provides a preparation method of a flexible pressure-sensitive fiber fabric, including:

[0006] Preparing a conductive material by uniformly mixing carbon, carbon nanotubes, carbon graphene, and silver powder in a predetermined ratio to obtain the conductive material;

[0007] 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;

[0008] Preparing 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 knitting the conductive fiber filaments with a preset fineness into a piezoresistive pressure-sensitive fabric through a weaving or knitting process.

[0009] In a second aspect, the present invention provides a flexible pressure-sensitive fiber fabric sensor, including:

[0010] An upper electrode substrate, which is prepared from cloth or leather and is used to provide mechanical support and surface protection so that the sensor can be sewn to the sensor usage terminal;

[0011] 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;

[0012] 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 sensing area of the electrode grid;

[0013] 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 by using the preparation method of the above flexible pressure-sensitive fiber fabric;

[0014] 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;

[0015] 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;

[0016] 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 sensing area of the electrode grid;

[0017] 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.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The present invention provides a method for preparing 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. Conductive fiber filaments and fabrics are prepared. The mixed material of the conductive material and the matrix material is formed into conductive fiber filaments with a preset fineness, and then the conductive fiber filaments with the preset fineness are woven into a piezoresistive pressure-sensitive fabric through a weaving or knitting process, thereby improving the mechanical strength, anti-friction property, and uniform conductivity dispersion of the flexible pressure-sensitive fiber fabric and ensuring voltage stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The 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 and descriptions thereof of the present invention 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 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:

[0021] 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;

[0022] Figure 2 is a schematic structural diagram of a pressure-sensitive fiber fabric sensor according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] 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 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 of 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.

[0024] Embodiment 1

[0025] Refer to Figure 1 - Figure 2 , this embodiment provides a method for preparing a flexible pressure-sensitive fiber fabric, including the following steps:

[0026] 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;

[0027] S102. Prepare a mixed material of a conductive material and a matrix material. Mix the conductive material with the matrix materials of polyester and nylon evenly in a planetary high-speed mixer to obtain a mixed material of the conductive material and the matrix material;

[0028] S103. Prepare conductive fiber filaments and a fabric. Prepare the mixed material of the conductive material and the matrix material into conductive fiber filaments with a preset fineness, and then weave the conductive fiber filaments with the preset fineness into a piezoresistive pressure-sensitive fabric through a weaving or knitting process.

[0029] 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, creep performance, etc.

[0030]

[0031] In the table, the mechanical strength of the flexible pressure-sensitive 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 pressure-sensitive 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 is ≤ 5% and the surface roughness change is ≤ 5% after 100,000 cycles. The anti-friction ability of the flexible pressure-sensitive 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 is ≤ 5% and the surface roughness change is ≤ 5% after 100,000 cycles. The conductive dispersion uniformity of the flexible pressure-sensitive 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 particle size distribution is ≤ 5% and the resistance fluctuation is ≤ 3%. The voltage resistance performance of the flexible pressure-sensitive 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, and the experimental data obtained are that the drift is ≤ 0.1% FS in 24 hours and the annual drift is ≤ 0.1% FS. Among them, FS (Full-Scale: full scale) represents the maximum output value within the range.

[0032] It should be noted that in this embodiment, a composite system of carbon, carbon nanotubes, 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 the uniform dispersion of conductivity (resistance fluctuation ≤ 3%) ensures the voltage stability.

[0033] In some preferred embodiments, when preparing the conductive fiber filaments, it includes: preparing a mixed material of the conductive material and the matrix material into conductive fiber filaments with a fineness of 20D - 200D through the co-blending spinning method and the special composite spinning process. It should be noted that the fiber filaments with a fineness of 20D - 200D can not only ensure sufficient mechanical strength (avoiding easy breakage due to being too thin), but also be 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 the core-shell structure) can further protect the conductive network and reduce external friction damage. In this embodiment, through the synergistic control of the 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.

[0034] 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 the conductivity drops sharply below this value. 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%).

[0035] 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 between silane coupling agent KH550 and the hydroxylated surface of carbon nanotubes, to improve the interfacial bonding force between the carbon nanotubes and the matrix material. It should be noted that the condensation reaction between silane coupling agent KH550 and hydroxylated carbon nanotubes to improve the interfacial bonding force between the carbon nanotubes and the matrix material can reduce the shedding of conductive particles, directly enhancing the anti-friction property (surface roughness change ≤ 5% after 100,000 cycles) and long-term stability (annual drift ≤ 0.1% FS).

[0036] 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 the carbon nanotubes, so as 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 the carbon nanotubes can be reduced, preventing agglomeration and enhancing the dispersion uniformity. On the basis of the silanization treatment, the uniformity of the conductive network is further optimized (standard deviation of SEM particle size distribution ≤ 5%).

[0037] 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, so as to improve the dispersion effect of carbon nanotubes and carbon fibers in the conductive material and prevent the agglomeration phenomenon 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 airflow pulverization is implemented on the mixture of the conductive material and the matrix material, so as 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. In coordination 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 airflow pulverization, the ultrasonic cavitation effect is used to break agglomerates, and airflow pulverization is used to refine particles, double guaranteeing the dispersion uniformity, achieving a resistance fluctuation ≤ 3% and an overload capacity ≥ 300% FS.

[0038] In some preferred embodiments, the mass ratio range of each component in the conductive material is specifically as follows: carbon 10% - 40%, carbon nanotubes 20% - 50%, carbon graphene 5% - 25%, and silver powder 5% - 35%. It should be noted that carbon (10% - 40%) serves 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 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 (meeting the creep performance standard).

[0039] 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 fillers. 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. In the range of the mass ratio of polyester to nylon being 1:1 to 1:4, the length change of the fiber is minimal after wet-dry cycling, and good breaking strength can be maintained simultaneously.

[0040] In some preferred embodiments, in the co-blending spinning method and the special composite spinning process, the pore diameter 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 a spinneret pore diameter of 0.1 mm - 0.5 mm can prevent the melt containing fillers from being blocked due to too small pore diameter, and at the same time is conducive to melt drawing to form a uniform cross-section; a 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 of the transverse fracture surface, and ensure that the modulus fluctuation in nanoindentation testing is small.

[0041] In some preferred embodiments, the woven or knitted process adopts a plain or twill weave, and 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 balance 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 provide sufficient deformation space for 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.

[0042] In some preferred embodiments, the flexible pressure-sensitive fabric is subjected to a finishing process after weaving. The finishing process includes heat setting and waterproof and stain-proof treatment. The heat setting temperature is 120-180 °C and the setting time is 15-45 min. It should be noted that the heat setting temperature of 120-180 °C and the setting time of 15-45 min can eliminate textile residual stress and lock the size, and the waterproof and stain-proof treatment can prevent water vapor and ions from infiltrating into the network of the flexible pressure-sensitive fabric during washing, thereby increasing the resistance.

[0043] In some preferred embodiments, the waterproof and stain-proof treatment is carried out by impregnation with a fluorocarbon 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 of 1%-5%, the impregnation temperature controlled at 50-80 °C, and the time of 10-30 min, a dense low-energy film layer can be formed on the fiber surface, but the air permeability is still maintained, avoiding blockage of pores at too high a concentration and reducing sensitivity, and avoiding incomplete film formation at too low a temperature.

[0044] In some preferred embodiments, the resistivity of the single filament of the conductive fiber filament is controlled between 10 -2 Ω·cm and 10 2 Ω·cm to meet the high sensitivity and high stability required by the flexible pressure-sensitive fabric sensor. The tensile strength of the conductive fiber filament is controlled at 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 between 10 -2 Ω·cm and 10 2 Ω·cm, which can ensure that the noise ratio is ≥20 dB in the whole range from 1 kPa micro-pressure to 500 kPa high pressure; below this value, the sensitivity is insufficient, and above this value, the signal decays and the driving voltage requirement increases. The tensile strength of the conductive fiber filament is controlled at 400-800 MPa, which can ensure that the fabric does not produce micro-cracks under multi-axial stress; the elongation at break is 20%-40%, which can endow the required elastic recovery for bending applications.

[0045] Example 2

[0046] See Figure 1 - Figure 2 , this embodiment provides a flexible pressure-sensitive fiber fabric sensor, including:

[0047] The upper electrode substrate 1, which is made of cloth or leather, is used to provide mechanical support and surface protection so that the sensor can be sewn to the sensor usage terminal;

[0048] The upper electrode trace layer 2 is 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 clamping terminal that clamps onto the upper electrode substrate;

[0049] The upper intensifying conductive fabric layer 3 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;

[0050] The flexible pressure-sensitive fiber fabric layer 4 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;

[0051] The lower electrode substrate 5 is made of cloth or leather to provide mechanical support and surface protection, enabling the sensor to be sewn onto the sensor usage terminal;

[0052] The lower electrode trace layer 6 is 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 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;

[0053] The lower intensifying conductive fabric layer 7 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;

[0054] 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.

[0055] It should be noted that in this embodiment, the multi-layer sandwich structure of the flexible pressure-sensitive fiber fabric sensor can solve technical problems such as unstable voltage, easy attenuation of the piezoresistive network, and short service life of the flexible pressure-sensitive fiber fabric sensor. First, both the upper and lower electrode substrates are made of fabric or leather, which can be sewn and bent. Their flexible buffering effect can disperse macroscopic stress when the sensor is folded, bent, or washed at the usage end, avoiding 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 are themselves oxidation-resistant and corrosion-resistant to sweat and washing liquids; the disk embroidery makes the metal wires in a state of winding and embedding with the substrate fibers, and its drawing 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, inhibit fiber powdering or filler migration caused by repeated compression, and delay the curing of the persistent resistance network. The flexible pressure-sensitive 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 pressure-sensitive fiber fabric in this embodiment are shown. Among them, the mechanical strength of the flexible pressure-sensitive 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 pressure-sensitive 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 is ≤ 5% and the surface roughness change is ≤ 5% after 100,000 cycles. The anti-friction ability of the flexible pressure-sensitive 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 is ≤ 5% and the surface roughness change is ≤ 5% after 100,000 cycles. The conductive dispersion uniformity of the flexible pressure-sensitive 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 is ≤ 5% and the resistance fluctuation is ≤ 3%. The pressure resistance performance of the flexible pressure-sensitive 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 is 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. Herein, 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. 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. At the same time, the uniform conductive dispersion (resistance fluctuation ≤ 3%) ensures voltage stability.

[0056] 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 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 forming conductive fiber filaments with a preset fineness from the mixed material of the conductive material and the matrix material, and then weaving the conductive fiber filaments with a preset fineness into a piezoresistive pressure-sensitive fabric through a weaving or knitting process; 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; When mixing the conductive material with the matrix material, it includes: subjecting carbon nanotubes to silanization treatment using a silane coupling agent KH550, and through the condensation reaction of 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; 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%.

2. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 1, wherein, When preparing the conductive fiber filaments, it includes: forming conductive fiber filaments with a fineness of 20D-200D from the mixed material of the conductive material and the matrix material 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, 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 the carbon nanotubes to improve the uniformity of the dispersion of conductive particles in the fabric.

4. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 3, characterized in that, 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 from occurring during the long-term use of the conductive material.

5. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 3, characterized in that, 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.

6. The preparation method of the flexible pressure-sensitive fiber fabric according to claim 5, characterized in that, The ultrasonic frequency used for ultrasonic dispersion is controlled at 20-40 kHz, and the dispersion time is 30-60 min.

7. 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, enabling the sensor to be sewn onto the sensor usage terminal; An upper electrode wiring layer, which is sewn onto the upper electrode substrate using stainless steel wires, carbon fiber filaments, or silver fiber filaments 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 sensitizing 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 1-6; Lower electrode substrate, which is prepared from cloth 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 trace 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 trace layer forms a biting 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 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 enhancement 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 enhancement conductive fabric layer, the lower electrode trace layer and the lower electrode substrate.

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