Conductive fabric and high-temperature pretreatment process thereof

Abstract

The invention relates to the technical field of functional fabrics, in particular to a conductive fabric, which is characterized in that the average resistance value of any three parts of the conductive fabric is in a range of 1-1000 ohms before treatment; the conductive fabric is subjected to high-temperature treatment, the temperature of high-temperature treatment is 80-300 DEG C, the treatment time is 10-180 min, and the change rate of the resistance value of the fabric is within the range of-50% to-5% compared with the resistance value before treatment. The technical problem that an existing conductive fabric is poor in resistance stability is solved. The invention further provides a high-temperature pretreatment process of the conductive fabric.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional fabric, in particular to a conductive fabric with stable performance after high-temperature treatment and a high-temperature pretreatment process thereof. BACKGROUND

[0002] With the rapid development of science and technology, intelligent electronic devices are gradually integrated into people's daily life, and the demand for functional fabrics with special functions is also increasing. As an important functional fabric, conductive fabric has shown great application potential in many fields. For example, in intelligent wearable devices, conductive fabric can be used to make sensors that can monitor physiological signals of the human body (such as heart rate, muscle electricity, etc.).

[0003] At present, there are various types of conductive fabrics on the market, such as metal fiber blended fabric, metal-plated fiber fabric, and conductive polymer coating fabric, etc. However, these conductive fabrics still have many problems in practical application. The resistance value of many conductive fabrics fluctuates greatly under different environmental conditions (such as temperature and humidity changes), which leads to unstable conductive performance, affecting the accuracy and reliability of electronic devices made based on the fabric. SUMMARY

[0004] Therefore, in view of the above problems, the present application provides a conductive fabric which solves the technical problem of poor resistance stability of existing conductive fabrics. And a high-temperature pretreatment process of conductive fabric is proposed.

[0005] To achieve the above purpose, the present application adopts the following technical scheme: a conductive fabric, the average resistance value of any three parts of the conductive fabric before treatment is in the range of 1Ω-1000Ω;

[0006] The conductive fabric is subjected to high-temperature treatment, the temperature of the high-temperature treatment is 80℃-300℃, the treatment time is 10min-180min, and the resistance value of the fabric changes by-50% to-5% compared with before treatment.

[0007] Further, the temperature of the high-temperature treatment is 120℃-180℃, the treatment time is 20min-100min, and the resistance value of the fabric changes by-40% to-10%; the temperature of the high-temperature treatment is 140℃

[0008] C-160℃, the treatment time is 30min-50min, and the resistance value of the fabric changes by-30% to-15%.

[0009] Further, in the high-temperature treatment process, the temperature rising rate is 1℃ / min-20℃ / min, and when the set temperature is reached, the temperature is kept constant for high-temperature treatment; after the high-temperature treatment is completed, the temperature falling rate is 1℃ / min-20℃ / min until it falls to room temperature.

[0010] Further, the tensile strength of the conductive fabric after high temperature treatment is between 50-200MPa, and the elongation at break is between 5%-100%.

[0011] Further, when the elongation at break is between 15%-35%, the change range of the resistance value of the fabric under different stretching states can be reduced by 10%-20%.

[0012] Further, the test method of the resistance value of the fabric is as follows: in an environment with a temperature of 25℃±2℃ and a relative humidity of 50%±5%, the conductive fabric is cut into a square sample with a size of 10cm×10cm, a four-probe tester is used to uniformly select five test points on the surface of the sample, and the average value of the resistance values of the five test points is taken as the resistance value of the sample.

[0013] Further, the conductive fabric is a composite fabric composed of conductive fibers and conductive polymers, wherein the mass fraction of the conductive fibers is 5-80%, and the mass fraction of the conductive polymers is 5-80%.

[0014] Further, the variation coefficient of the surface resistance uniformity of the conductive fabric is between 10%-30%;

[0015] The test method of the variation coefficient is as follows: at least 10 different positions are uniformly selected on the surface of the conductive fabric, a four-probe tester or a high resistance meter is used to measure the surface resistance values of each position, the standard deviation of the surface resistance values of all measurement points is calculated, and the ratio of the standard deviation to the average value is taken as the variation coefficient; the variation coefficient = standard deviation / average value×100%; the area occupied by the 10 different positions is less than 5% of the total area, and the distance between the measurement points is not less than 10cm, so as to ensure the independence and representativeness of the test data.

[0016] Further, in the Martindale abrasion test, the conductive fabric has a friction frequency of 5000-20000 times when the conductive performance is obviously reduced or the surface is damaged.

[0017] Further, after 10-30 standard washes, the change rate of the resistance value of the conductive fabric compared with the initial value is between 1% and 20%.

[0018] Further, a high temperature pretreatment process of a conductive fabric includes the following steps:

[0019] Step S1, place the conductive fabric in a vacuum or inert gas environment, and use a direct current arc plasma torch to scan and treat the surface, high-energy particles in the plasma bombard the surface of the fabric, remove organic contaminants, dust and oxide layers, and introduce polar groups to enhance the bonding force between the fibers and the conductive polymers;

[0020] Step S2, the pretreated fabric is placed in a high-temperature furnace, and a gradient heating mode is adopted:

[0021] In the first stage, the temperature is increased to 140-160 DEG C at a rate of 2-5 DEG C / min, and the fabric is uniformly heated for 30 min to avoid thermal stress concentration;

[0022] In the second stage, the temperature is increased to the target temperature of 200-300 DEG C at a rate of 6-10 DEG C / min, and the fabric is kept at the temperature for 60-180 min to promote the cross-linking reaction of the conductive polymer and the fiber;

[0023] In the third stage, the fabric is naturally cooled to room temperature at a rate of 1-3 DEG C / min to prevent the resistance value from fluctuating due to rapid cooling;

[0024] Step S3, plasma post-treatment, after high-temperature treatment, the plasma torch is used again, the power is 30-50 W, and the time is 1-2 min, the surface of the fabric is bombarded with low energy, the inert gas plasma is introduced to neutralize the residual active groups on the surface, and a passivation layer is formed to prevent the resistance value from drifting due to environmental oxidation or moisture.

[0025] By adopting the foregoing technical solutions, the application has the following advantages:

[0026] 1. The average resistance value of the conductive fabric at any three positions before treatment is in the range of 1-1000 ohms, which covers a variety of cases from low resistance to higher resistance. After high-temperature treatment at a specific temperature (80-300 DEG C) and time (10-180 min), the resistance value of the fabric changes by-50% to-5%. This means that the resistance of the conductive fabric can be regulated to some extent by high-temperature treatment, so that the resistance value meets the requirements of actual application, and the resistance change is within a controllable range, improving the stability and predictability of the fabric resistance.

[0027] 2. The parameter range of high-temperature treatment is further refined. When the high-temperature treatment temperature is 120-180 DEG C and the treatment time is 20-100 min, the resistance value change rate is controlled in the range of-40% to-10%; when the temperature is 140-160 DEG C and the treatment time is 30-50 min, the resistance value change rate is controlled in the range of-30% to-15%.

[0028] 3. The specified heating rate during the high-temperature treatment is 1℃ / min-20℃ / min, and the cooling rate is 1℃ / min-20℃ / min. A reasonable heating rate can prevent damage to the internal structure of the fabric due to excessively rapid heating, which would affect its conductivity. An appropriate cooling rate helps prevent internal stress from forming during cooling, which could lead to fabric deformation or performance degradation. By controlling the heating and cooling rates, the high-temperature treatment process can be optimized, further improving the performance stability and quality of the conductive fabric. After reaching the set temperature, a heat preservation treatment is performed to ensure that the fabric fully reacts in the high-temperature environment, achieving the expected change in resistance. Simultaneously, a uniform cooling process also contributes to the stability of the fabric's performance, ensuring that the conductive fabric after high-temperature treatment meets the requirements.

[0029] 4. After high-temperature treatment, the conductive fabric exhibits a tensile strength between 50-200 MPa and an elongation at break between 5%-100%. Higher tensile strength indicates better tensile resistance, enabling it to withstand certain external forces without breaking. A suitable elongation at break provides the fabric with flexibility and deformation capacity under tension, preventing brittle fracture. These mechanical properties make the conductive fabric more durable in practical applications and adaptable to various usage environments and stress conditions.

[0030] When the elongation at break is between 15% and 35%, the variation in the resistance value of the fabric under different tensile conditions can be reduced by 10% to 20%. This means that within this range of elongation at break, the resistance value of the conductive fabric can remain relatively stable when stretched, reducing resistance fluctuations caused by fabric deformation. This is crucial for applications that require operation under dynamic tensile conditions, such as wearable devices for motion monitoring, as it improves the measurement accuracy and reliability of the device.

[0031] 5. A clear testing method for fabric resistance values ​​was established. Testing was conducted in a specific temperature (25℃±2℃) and relative humidity (50%±5%) environment, eliminating environmental interference and ensuring the accuracy of the results. The conductive fabric was cut into 10cm×10cm square samples, and five test points were evenly selected on the sample surface using a four-probe tester, with the average value taken. This method provides a more comprehensive and accurate reflection of the conductive fabric's resistance performance, offering a reliable basis for product quality control and performance evaluation.

[0032] 6. The conductive fabric is a composite fabric, made of conductive fibers and conductive polymers, with each component accounting for 5-80% of the total mass. This composite structure combines the advantages of conductive fibers and conductive polymers. Conductive fibers typically possess good conductivity and mechanical strength, while conductive polymers offer excellent flexibility and processability. By appropriately adjusting the ratio of the two, conductive fabrics with superior overall performance can be obtained, such as simultaneously possessing high conductivity, good flexibility, and mechanical strength.

[0033] 7. The coefficient of variation of the surface resistance uniformity of conductive fabric is between 10% and 30%, indicating that the resistance value varies little at different locations on the fabric surface and the resistance distribution is uniform. This is very important for applications requiring large-area uniform conductivity, ensuring consistent conductivity across the entire fabric surface and improving product performance and quality.

[0034] 8. In the Martindale abrasion test, the conductive fabric exhibits good abrasion resistance when the number of abrasion cycles that result in a significant decrease in conductivity or surface damage is between 5,000 and 20,000. After 10-30 standard washes, the resistance value of the conductive fabric changes by 1% to 20% compared to its initial value, indicating that the fabric has good wash resistance. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the present invention.

[0036] Figure 2 This is a schematic diagram of another embodiment of the present invention. Detailed Implementation

[0037] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0038] refer to Figure 1 , Figure 2 This embodiment provides a conductive fabric, which is a composite fabric composed of conductive fibers 1 and conductive polymers 2, such as... Figure 1 or Figure 2 As shown, other methods are also possible; no specific limitation is made to the composite molding method here. The conductive fiber is silver-plated nylon fiber, which has good conductivity and stability, and its mass percentage is set at 50%. The conductive polymer is polypyrrole, which has high conductivity and flexibility, and its mass percentage is also 50%. By composited with silver-plated nylon fiber and polypyrrole, the fabric combines the advantages of both, ensuring good conductivity while also possessing a certain degree of flexibility and durability.

[0039] One of the processing techniques for the aforementioned conductive fabric includes:

[0040] 1. Fiber Pretreatment: Clean the silver-plated nylon fibers to remove surface impurities and oil. Use deionized water and an appropriate amount of neutral detergent, and clean with an ultrasonic cleaner for 20-40 minutes at a temperature of 30-50℃. Then rinse thoroughly with deionized water and dry in an oven at 50-70℃ for later use.

[0041] 2. Preparation of conductive polymer solution: Dissolve polypyrrole in a specific organic solvent, such as N-methylpyrrolidone (NMP), to prepare a 10% (w / w) polypyrrole solution. During the preparation process, use a magnetic stirrer to stir at 40-60°C for 1-3 hours to ensure that the polypyrrole is fully dissolved and a homogeneous solution is obtained.

[0042] 3. Composite Process: A dip-drying method is used to composite silver-plated nylon fibers with a polypyrrole solution. The pre-treated silver-plated nylon fibers are immersed in the polypyrrole solution for 20-40 minutes to ensure full absorption. The fibers are then removed and dried in an oven at 70-90℃ for 1-3 hours to form a uniform coating of polypyrrole on the fiber surface. This dip-drying process is repeated three times to increase the adhesion of polypyrrole to the fibers and improve the conductivity of the fabric.

[0043] 4. Weaving Process: The composite silver-plated nylon fibers are woven into a plain weave fabric using a rapier loom. During the weaving process, the density of both warp and weft yarns is controlled at 25-35 yarns / cm to ensure the fabric's structural stability and uniform conductivity.

[0044] The parameters in the above processing technology can be adjusted according to actual needs; they are merely preferred implementation methods.

[0045] Of course, conductive fabrics can also have other structures, such as coatings or plating, chemical plating, polymerization, or nano-coating. This solution does not limit the specific structure of the conductive fabric.

[0046] After the conductive fabric is formed, it still needs to undergo post-processing, including high-temperature treatment, specifically including:

[0047] 1. Heating Stage: Place the woven conductive fabric into a high-temperature oven and set the heating rate to 10℃ / min. During the heating process, closely monitor the temperature inside the oven to ensure uniform and stable heating. When the temperature reaches 140℃, enter the heat preservation stage. The selection of 140℃ is based on the fact that this temperature range, as described in claim 2, allows the rate of change of the fabric's resistivity to be controlled within an optimal range, while also considering the balance of various fabric properties.

[0048] 2. Heat preservation stage: The fabric undergoes high-temperature treatment at 140℃ for 40 minutes. During this period, the molecular structure within the fabric undergoes certain changes, and the bond between the conductive fibers and the conductive polymer becomes tighter, thereby affecting the fabric's resistance value. This combination of heat preservation time and temperature allows the fabric's resistance value change rate to be controlled within the range of -30% to -15%, satisfying the requirements of claim 2.

[0049] 3. Cooling Stage: After the high-temperature treatment, set the cooling rate to 10℃ / min until it reaches room temperature. Slow cooling can prevent the fabric from developing internal stress due to rapid temperature changes, which could lead to fabric deformation or performance degradation.

[0050] For testing conductive fabrics, the appropriate method can be selected based on actual needs. For example, resistance testing can utilize methods such as the four-probe method, two-probe method, and van der Burg method. The testing methods in this solution are as follows:

[0051] (I) Resistance value test

[0052] In an environment with a temperature of 25℃±2℃ and a relative humidity of 50%±5%, the conductive fabric was cut into square samples of 10cm×10cm. Using a four-probe tester, five test points were evenly selected on the surface of the sample, and the average resistance value of the five test points was taken as the resistance value of the sample. After testing, the average resistance value of any three parts of the conductive fabric before treatment was in the range of 500Ω-800Ω. After high-temperature treatment, the resistance value of the fabric changed by a rate of -30% to -15% compared to before treatment.

[0053] (II) Tensile property testing

[0054] The tensile properties of the conductive fabric were tested using a universal testing machine. The fabric was cut into standard specimens, and the tensile speed was set to 100 mm / min. The tensile strength and elongation at break were tested. The results showed that after high-temperature treatment, the conductive fabric exhibited a tensile strength of approximately 120 MPa and an elongation at break of approximately 25%, falling within the range of 50-200 MPa and 5%-100% respectively. Furthermore, when the elongation at break was between 15% and 35%, testing the fabric's resistance under different tensile conditions revealed that the variation in resistance could be reduced by approximately 15%.

[0055] (III) Surface resistance uniformity test

[0056] According to the test method of claim 8, 12 different locations (the area occupied by the 12 different locations is less than 5% of the total area, and the distance between each measurement point is not less than 10 cm) are uniformly selected on the surface of the conductive fabric. The surface resistance value of each location is measured using a four-probe tester. The standard deviation of the surface resistance values ​​of all measurement points is calculated, and the ratio of its standard deviation to the mean is used as the coefficient of variation. The test results show that the coefficient of variation of the surface resistance uniformity of the conductive fabric is approximately 20%, between 10% and 30%.

[0057] (iv) Abrasion resistance test

[0058] The abrasion resistance of the conductive fabric was tested using a Martindale abrasion tester. The friction pressure was set to 12 kPa, and the friction head was a 25 mm diameter circle. Friction was applied according to standard testing methods until the fabric showed a significant decrease in conductivity or surface damage. The test results showed that the conductive fabric exhibited significant conductivity degradation or surface damage after approximately 12,000 abrasion cycles in the Martindale abrasion test, with a range of 5,000-20,000 cycles.

[0059] (V) Washing performance test

[0060] The conductive fabric was washed using a household washing machine with a neutral detergent at 30°C for 30 minutes, followed by a 5-minute spin cycle. After 20 standard washes, the fabric's resistance was tested, revealing a change of approximately 15% in resistance compared to the initial value, ranging from 1% to 20%.

[0061] The conductive fibers mentioned above can be carbon fibers, such as polyacrylonitrile-based carbon fibers, or metal fibers, such as copper wire or silver fibers, or other fibers capable of conducting electricity, such as silver-plated fibers. The conductive polymers mentioned above can be polyaniline, polypyrrole, and polythiophene, or other types of conductive polymers. The ratio of conductive fibers to conductive polymers can be selected according to actual needs.

[0062] The aforementioned conductive fabric undergoes high-temperature treatment at temperatures ranging from 80℃ to 300℃ for 10 to 180 minutes. Alternatively, high-temperature treatment at 120℃ to 180℃ for 20 to 100 minutes controls the fabric's resistance change rate within the range of -40% to -10%. For example, setting the temperature to 150℃ and the treatment time to 50 minutes allows for more precise control of the resistance change rate within the desired range. When the high-temperature treatment temperature is 140℃ to 160℃ for 30 to 50 minutes, the fabric's resistance change rate is controlled within the range of -30% to -15%. For instance, a temperature of 150℃ and a treatment time of 40 minutes allows for further precise control of the resistance, ensuring the change rate remains within a manageable range.

[0063] During the high-temperature treatment, the heating rate is 1℃ / min-20℃ / min. Preferably, for conductive fabrics sensitive to temperature changes, the heating rate can be controlled at 5℃ / min-10℃ / min to avoid damage to the internal structure of the fabric due to excessively rapid heating, which would affect its conductivity. Once the set temperature is reached, the fabric is kept at that temperature for further high-temperature treatment to ensure a full reaction. After the high-temperature treatment, the cooling rate is 1℃ / min-20℃ / min until the temperature drops to room temperature. Similarly, for fabrics with higher requirements, the cooling rate can be controlled at 5℃ / min-10℃ / min to prevent internal stress from forming during cooling, which could lead to fabric deformation or performance degradation, thus ensuring the stability of the conductive fabric after high-temperature treatment.

[0064] After high-temperature treatment, the conductive fabric exhibits a tensile strength between 50 and 200 MPa. For example, a tensile strength of 100 MPa indicates good tensile strength, capable of withstanding certain external forces without breaking. The elongation at break is between 5% and 100%. A break elongation of 30% indicates that the fabric possesses a certain degree of flexibility and deformation under tension, making it less prone to brittle fracture. These excellent mechanical properties make conductive fabrics suitable for wearable devices and other applications requiring resistance to certain mechanical forces, thus broadening their application range. When the elongation at break is between 15% and 35%, the change in resistance under different stretching conditions can be reduced by 10% to 20%. For example, without optimization, a 20% stretch results in a 30% change in resistance; after optimization to bring the elongation at break within this range, the resistance change can be reduced to 24% to 27%, minimizing the impact of stretching on resistance. This is crucial for motion monitoring wearable devices, improving measurement accuracy and reliability and ensuring stable resistance of the conductive fabric during human movement.

[0065] Environmental conditions were controlled using a constant temperature and humidity chamber at a temperature of 25℃±2℃ and a relative humidity of 50%±5%. The conductive fabric was cut into 10cm×10cm square samples. A four-probe tester, a standard device in this field, was used to measure the resistance by having four probes contact the sample surface. Five test points were evenly selected on the sample surface, for example, the center point and four corner points in a cross pattern. The average resistance value of the five test points was taken as the resistance value of the sample. This testing method eliminates environmental interference, accurately reflects the resistive performance of the conductive fabric, and provides a reliable basis for product quality control.

[0066] The aforementioned conductive fabric can be a woven structure, with conductive fibers comprising 5-80% of the total mass and conductive polymers comprising 5-80% of the total mass. For example, a 30% conductive fiber and 70% conductive polymer combination combines the high strength of conductive fibers with the flexibility of conductive polymers, giving the conductive fabric excellent overall performance, such as good conductivity and flexibility, making it suitable for fields such as smart textiles. The specific mass percentage can be selected based on actual needs.

[0067] The coefficient of variation (COV) for the surface resistance uniformity of conductive fabrics ranges from 10% to 30%. The COV test method involves uniformly selecting at least 10 different locations on the conductive fabric surface and measuring the surface resistance at each location using a four-probe tester or a high-resistivity meter (both standard measuring equipment in this field). The standard deviation of the surface resistance values ​​at all measurement points is calculated, and the ratio of this standard deviation to the mean is used as the COV: COV = (Standard Deviation / Mean) × 100%. The area occupied by the 10 different locations should be less than 5% of the total area, and the distance between each measurement point should be no less than 10 cm to ensure the independence and representativeness of the test data. For example, measuring the resistance values ​​at 10 points and calculating a COV of 20% indicates a relatively uniform surface resistance distribution, suitable for applications requiring large-area uniform conductivity, such as electromagnetic shielding materials.

[0068] From a microscopic perspective, the distribution density and connection method of conductive fibers or conductive particles in a fabric affect its resistance. If the conductive material is densely distributed and well connected, there is less resistance to electron transport in the fabric, resulting in lower resistance. Conversely, if the conductive material is sparsely distributed or there are many breaks in the connection, electron transport is hindered, leading to higher resistance.

[0069] Conductive fibers, such as silver-plated nylon fibers, utilize the excellent conductivity of silver, allowing electrons to move freely within the silver layer. Conductive polymers, such as polypyrrole, possess conjugated π bonds in their molecular structure, enabling electrons to move delocalized within the molecular chains, thus conducting electricity. When these two are combined, the conductive fibers provide a rapid, long-distance electron transport channel, while the conductive polymer fills the gaps between the fibers, forming a continuous conductive network and enhancing the overall conductivity of the fabric.

[0070] The resistance of conductive fabric is determined by the characteristics and distribution of its internal conductive materials, as well as the fabric's structure. Before processing, the average resistance of any three parts of the conductive fabric is set within the range of 1Ω-1000Ω, based on the conductivity requirements of different application scenarios.

[0071] In practical applications,

[0072] Low resistance (1Ω-100Ω): Suitable for scenarios with high current transmission requirements, such as circuit connections and conductive paths for electronic components. For example, in some wearable electronic devices, it is necessary to efficiently transfer battery power to various electronic components. Low-resistance conductive fabrics can reduce energy loss and improve the device's battery life.

[0073] Medium resistance (100Ω-500Ω): Suitable for electronic applications where current is limited, such as electromagnetic shielding materials. The conductive material of medium resistance can absorb and reflect electromagnetic waves to a certain extent, without generating excessive heat due to excessive current due to low resistance, thus avoiding affecting the normal operation of the equipment.

[0074] High resistance (500Ω-1000Ω): Suitable for sensor applications requiring precise current control. The high-resistance conductive fabric can produce a significant resistance response to minute changes in current, thereby enabling accurate measurement of physical quantities such as temperature, pressure, and humidity.

[0075] High-temperature treatment is a crucial step in altering the resistance of conductive fabrics. By applying high temperatures, the internal crystal structure, molecular arrangement, and interfacial state between the conductive material and the matrix material can be changed, thereby affecting electron transport and ultimately controlling the fabric's resistance. In some cases, to prevent oxidation or other chemical reactions of the conductive material at high temperatures, high-temperature treatment in a specific atmosphere is necessary. Commonly used atmospheres include inert gases such as nitrogen and argon. By introducing an inert gas into the high-temperature treatment equipment, oxygen within the equipment can be eliminated, protecting the conductive material from oxidation.

[0076] Low-temperature range (80℃-150℃): Within this temperature range, the main processes are the evaporation of adsorbed moisture on the surface of the conductive material and some minor physical changes. For example, after the moisture on the surface of the conductive fibers evaporates, the contact between the fibers becomes tighter, the obstacle to electron transport decreases, and the resistance value will decrease to some extent, but the rate of change is relatively small, generally between -5% and -20%. This temperature treatment is suitable for situations where the required change in resistance is small and only the surface moisture of the fabric needs to be removed or preliminary pretreatment is required.

[0077] Mid-temperature range (150℃-250℃): This temperature range is where the internal structure of conductive materials undergoes significant changes. For some conductive polymers, such as polyaniline, thermal decomposition and rearrangement reactions occur at this temperature, leading to a significant change in their conductivity. Simultaneously, the interface between the conductive fibers and the matrix material also interacts, improving electron transport channels. Within this temperature range, the rate of change in resistance is relatively large, generally between -20% and 40%, which can meet the needs of most applications requiring significant resistance adjustment.

[0078] High-temperature range (250℃-300℃): When the temperature reaches above 250℃, conductive materials may undergo more drastic chemical reactions or structural changes. For example, some conductive metal fibers may experience oxidation or grain growth, leading to further changes in resistance. However, excessively high temperatures may also damage the conductive materials, affecting the overall performance of the fabric. Within this temperature range, the resistance change rate is between -40% and -50%, requiring careful control of processing time and temperature to avoid over-processing.

[0079] Short-time processing (10-60 minutes): This involves high-temperature treatment over a short period, during which changes in the conductive material are primarily concentrated in the outer layer or surface. For example, the oxide layer on the surface of conductive fibers may only be initially formed or removed, resulting in a relatively slow and small rate of change in resistance. This short-time processing is suitable for conductive fabrics that require rapid resistance adjustment or are heat-sensitive.

[0080] Medium-duration treatment (60-120 minutes): As the treatment time increases, the high temperature gradually penetrates deeper into the conductive material, causing more significant changes in its internal structure. Processes such as the rearrangement of conductive polymer molecular chains and the interfacial fusion between conductive fibers and the matrix material become more complete, leading to a corresponding increase in the rate of change in resistance. Treatment within this timeframe allows for a more stable adjustment of the resistance value.

[0081] Prolonged processing (120-180 minutes): Prolonged high-temperature processing may cause conductive materials to overreact or age. For example, conductive polymers may undergo excessive decomposition, and conductive fibers may become brittle. While the resistance value may continue to change, it may lead to a decline in other fabric properties, such as reduced mechanical strength. Therefore, prolonged processing requires strict control of temperature and other conditions to ensure the overall performance of the fabric.

[0082] By appropriately selecting the temperature and time parameters for high-temperature treatment, the rate of change in the resistance of conductive fabric can be controlled within the range of -50% to -5%.

[0083] In addition, before high-temperature treatment, the conductive fabric can be surface-modified using plasma (such as oxygen or nitrogen plasma). This can be combined with plasma cleaning technology, which can more effectively remove organic pollutants and impurities from the fiber surface without damaging the fibers, improving the activity of the fiber surface and enhancing the bonding force between the conductive polymer and the fiber. High-temperature treatment is then performed to further optimize the resistance stability. The plasma treatment power can be 50-200W, and the time can be 2-10 minutes.

[0084] You can refer to a high-temperature pretreatment process for conductive fabrics, which includes the following steps:

[0085] Step S1: Place the conductive fabric in a vacuum or inert gas environment and scan the surface using a DC arc plasma torch. High-energy particles in the plasma bombard the fabric surface, removing organic contaminants, dust, and oxide layers, while simultaneously introducing polar groups to enhance the bonding force between the fibers and the conductive polymer.

[0086] The gas pressure inside the processing chamber is maintained stable by adjusting the vacuum pump speed and gas intake rate. Nitrogen can be used as the inert gas. The DC arc plasma torch has a power of 50-200W and a duration of 2-10 minutes. O3 can be used as a high-energy sample. + or OH - The polar group can be a hydroxyl or a carboxyl group.

[0087] Step S2: Place the pretreated fabric in a high-temperature furnace and use a gradient heating method.

[0088] First stage: Increase the temperature to 150℃ at a rate of 5℃ / min and keep it warm for 30 minutes to ensure that the fabric is heated evenly and to avoid thermal stress concentration.

[0089] Second stage: Increase the temperature to the target temperature of 200-300℃ at a rate of 10℃ / min, and hold for 60-180min to promote the cross-linking reaction between the conductive polymer and the fiber.

[0090] The third stage: natural cooling to room temperature, with the cooling rate controlled within 2℃ / min to prevent fluctuations in resistance value due to rapid cooling.

[0091] This system utilizes hot air circulation or infrared heating tubes to achieve zoned heating, ensuring a temperature difference of ≤5℃ between the fabric center and edges, thus guaranteeing uniform resistance. Furthermore, miniature sensors can be deployed on the fabric surface to provide real-time feedback on resistance changes and dynamically adjust temperature parameters, such as using a four-probe array.

[0092] Step S3, Plasma Post-processing

[0093] After high-temperature treatment, a plasma torch is used again with a power of 30-50W for 1-2 minutes to bombard the fabric surface with low energy. By introducing inert gas plasma, residual active groups on the surface are neutralized to form a passivation layer, preventing the resistance value from drifting due to environmental oxidation or humidity.

[0094] In this process, excessive bombardment should be avoided to prevent damage to the fabric surface, while ensuring that the passivation layer thickness is uniform and less than 100 nm. The passivation layer formed by plasma post-treatment can block the erosion of conductive paths by environmental factors such as oxygen and moisture, improving resistance stability by more than 30%.

[0095] Within the high-temperature pretreatment chamber, a static magnetic field of 0.1-1T can be applied to guide the conductive filler to align along the magnetic field direction, forming a low-resistance pathway. Furthermore, this magnetic field can be a gradient magnetic field, such as a weak central magnetic field and a strong peripheral magnetic field. The gradient magnetic field can be controlled according to actual needs to compensate for differences in the internal resistance of the fabric and enhance uniformity. The conductive filler can be carbon nanotubes, silver nanowires, etc.

[0096] Alternatively, electrostatic spraying can be used, where the conductive polymer solution is atomized into fine droplets by an electrostatic spraying device and uniformly deposited on the surface of the conductive fibers, forming a thinner and more uniform conductive coating. This method can improve the adhesion efficiency of the conductive polymer on the fibers.

[0097] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. An electrically conductive fabric, characterized in that, The average resistance value of any three parts of the conductive fabric before treatment is in the range of 1 Ω-1000 Ω; The conductive fabric is treated at a high temperature of 80-300 ℃ for 10-180 min, and the resistance value of the fabric changes by -50% to -5% compared with that before treatment.

2. The conductive fabric of claim 1, wherein, The resistance value of the fabric changes by -40% to -10% when the fabric is treated at a high temperature of 120-180 ℃ for 20-100 min, and the resistance value of the fabric changes by -30% to -15% when the fabric is treated at a high temperature of 140-160 ℃ for 30-50 min.

3. The conductive fabric of claim 2, wherein, During the high-temperature treatment, the temperature is raised at a rate of 1-20 ℃ / min, and after reaching the set temperature, the temperature is kept constant for high-temperature treatment; after the high-temperature treatment is completed, the temperature is lowered at a rate of 1-20 ℃ / min until it reaches room temperature.

4. The conductive fabric of claim 1, wherein, After the high-temperature treatment, the tensile strength of the conductive fabric is between 50-200 MPa, and the elongation at break is between 5%-100%.

5. The conductive fabric of claim 4, wherein, When the elongation at break is between 15%-35%, the resistance value of the fabric under different stretching states can be reduced by 10%-20%.

6. The conductive fabric according to any one of claims 1 to 4, wherein The test method for the resistance value of the fabric is as follows: in an environment with a temperature of 25 ℃±2 ℃ and a relative humidity of 50%±5%, the conductive fabric is cut into a square sample of 10 cm×10 cm, five test points are uniformly selected on the surface of the sample using a four-probe tester, and the average value of the resistance values of the five test points is taken as the resistance value of the sample.

7. The conductive fabric according to any one of claims 1 to 4, wherein The conductive fabric is a composite fabric composed of conductive fibers and conductive polymers, wherein the mass fraction of the conductive fibers is 5-80%, and the mass fraction of the conductive polymers is 5-80%.

8. The conductive fabric according to any one of claims 1 to 4, wherein The coefficient of variation of the surface resistance uniformity of the conductive fabric is between 10%-30%; The test method for the coefficient of variation is as follows: at least 10 different positions are uniformly selected on the surface of the conductive fabric, the surface resistance values of each position are measured using a four-probe tester or a high-resistance meter, the standard deviation of the surface resistance values of all measurement points is calculated, and the ratio of the standard deviation to the average value is taken as the coefficient of variation; the coefficient of variation = standard deviation / average value×100%; the area occupied by the 10 different positions is less than 5% of the total area, and the spacing between the measurement points is not less than 10 cm, so as to ensure the independence and representativeness of the test data.

9. The conductive fabric according to any one of claims 1 to 4, wherein, In the Martindale abrasion test, the conductive fabric has a friction frequency of 5000-20000 times before the conductive performance decreases obviously or the surface is damaged.

10. A high temperature pre-treatment process for an electrically conductive fabric, characterized by: The method comprises the following steps: Step S1: placing the conductive fabric in a vacuum or inert gas environment, and scanning the surface using a direct current arc plasma torch, so that high-energy particles in the plasma bombard the surface of the fabric, remove organic contaminants, dust and oxide layers, introduce polar groups, and enhance the bonding force between the fibers and the conductive polymers; Step S2: placing the pretreated fabric in a high-temperature furnace and using a gradient heating method The first stage is to increase the temperature to 140-160℃ at a rate of 2-5℃ / min, and keep the temperature for 30 min, so as to heat the fabric uniformly and avoid thermal stress concentration; The second stage is to increase the temperature to the target temperature of 200-300℃ at a rate of 6-10℃ / min, and keep the temperature for 60-180 min, so as to promote the cross-linking reaction between the conductive polymer and the fiber; The third stage is to cool to room temperature naturally, and the cooling rate is controlled to be within 1-3℃ / min, so as to prevent the resistance value from fluctuating due to rapid cooling; Step S3, plasma post-treatment: after high-temperature treatment, the plasma torch is used again, the power is 30-50W, and the time is 1-2 min, the surface of the fabric is bombarded with low energy, the inert gas plasma is introduced to neutralize the residual active groups on the surface, a passivation layer is formed, and the resistance value is prevented from drifting due to environmental oxidation or moisture.

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