A stretchable flexible fabric circuit and its preparation method and application

Abstract

The present invention discloses a stretchable flexible fabric circuit and its preparation method and application, belonging to the field of flexible circuit technology. The method comprises the following steps: subjecting an elastic fabric to plasma treatment, then coating both sides of the elastic fabric with a metal film by magnetron sputtering to obtain an elastic conductive fabric; subjecting a PET film and a hot melt film to a first hot pressing, then placing a fabric substrate on the hot melt film and subjecting it to a second hot pressing to obtain a PET / fabric composite; and cutting the PET / fabric composite according to a circuit design pattern to obtain a mold; preparing two identical molds, placing the elastic conductive fabric on the molds and fixing them. After fixing, another identical mold is placed on top of the elastic conductive fabric, and then placed on a photolithography platform for double-sided photolithography along the designed circuit pattern to obtain a stretchable flexible fabric circuit. The stretchable flexible fabric circuit has good air permeability, is lightweight and thin, conforms well to the human body, and has excellent stability and water resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible circuits, and in particular to a stretchable flexible fabric circuit and a preparation method and application thereof. Background Art

[0002] With the development of technology, the demand for smart textiles for motion monitoring continues to increase, and the requirements for the comfort of smart textiles are gradually increasing. Among them, flexible circuits used to connect electronic components are an important component of smart textiles. The performance of flexible circuits can not only affect the stability of signal transmission, but also the comfort of smart textiles.

[0003] The fabric circuit preparation methods in the prior art mainly include embroidery, chemical coating, weaving with conductive yarns, and cutting and pasting. The embroidery method is to embroider the conductive yarn on the base fabric with the help of a computer, and its disadvantage is that the degree of stretching is small. The chemical coating method is to coat the conductive material on the surface of the fabric substrate by printing. Its disadvantage is that the coating has poor wear resistance, and the resistance of the fabric circuit changes greatly or is easy to break after multiple stretching. The weaving method is to weave the conductive yarn into the fabric circuit by weaving or knitting. The disadvantage is that it is difficult to achieve patterning and the degree of stretchability is small. The cutting and pasting method is to cut the conductive fabric according to the designed pattern and paste it on the surface of the non-elastic or elastic fabric to form a patterned flexible circuit, but its disadvantage is that the prepared flexible circuit is not integrated with the substrate, the thickness is relatively thick, the flexibility and elasticity are reduced, and the recovery of the circuit during stretching will be affected by the pasting material.

[0004] Invention patent CN108385257A discloses a stretchable fabric circuit, which is made of non-conductive yarn and conductive yarn bent into loops and interwoven with each other. This method has certain stretchability, but it is difficult to prepare complex patterns. Invention patent CN112954908A discloses a method for making a fabric circuit based on inkjet printing and chemical deposition, which prepares a fabric circuit by inkjet printing and chemical copper deposition. This method can be patterned, but the degree of stretchability is small, and stretching can easily damage the coating. Utility model CN216514461U discloses a stretchable fabric conductor and a fabric with a circuit, which is made by introducing metal conductive yarn into the fabric substrate, but it can only form continuous bends or waves in the same direction, so its degree of stretchability is small and it is difficult to prepare complex patterns. Invention patent CN111906448A discloses a laser etching process method for double-sided transparent conductive materials. It uses the principle of total reflection to adjust the optical path and produce corresponding patterns on the A and B sides of the material. However, this process method is only suitable for transparent substrates, and the A and B sides of the material are non-contact due to the presence of an intermediate transparent medium film layer. This method is not suitable for microporous breathable fabric substrates. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a stretchable flexible fabric circuit and its preparation method and application. The stretchable flexible fabric circuit is soft, breathable, resistant to bending, stretchable, has stable conductivity, and is washable.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing a stretchable flexible fabric circuit comprises the following steps:

[0008] The elastic fabric is subjected to plasma treatment and then coated with a metal film on both sides of the elastic fabric by magnetron sputtering to obtain an elastic conductive fabric;

[0009] The PET film and the hot melt film are subjected to a first heat pressing, and then the fabric substrate is placed on the hot melt film and subjected to a second heat pressing to obtain a PET / fabric composite, and the PET / fabric composite is cut according to the circuit design pattern to obtain a mold;

[0010] Prepare two identical molds, place the elastic conductive fabric on the mold and fix it. After fixing it, place another identical mold on top of the elastic conductive fabric, and then place it on the photolithography platform. Perform double-sided photolithography along the designed circuit pattern to obtain a stretchable flexible fabric circuit.

[0011] As a preferred embodiment of the present invention, the elastic fabric is woven from nylon and spandex in a loop manner, the nylon is 30D-50D nylon, the spandex is 20D-40D spandex, and the mass ratio of nylon to spandex is (75-85):(15-25).

[0012] As a preferred embodiment of the present invention, the weight of the elastic fabric is 80g / m 2 ~120g / m 2 The thickness is 0.37mm~0.42mm, the longitudinal density is 200 pieces / 5cm~220 pieces / 5cm, and the transverse density is 115 pieces / 5cm~135 pieces / 5cm.

[0013] As a preferred embodiment of the present invention, the plasma treatment is carried out in a plasma reaction vessel, the power of the plasma treatment is 250W to 350W, and the time is 200s to 400s.

[0014] As a preferred embodiment of the present invention, the magnetron sputtering uses conductive particles as target materials, the power of the magnetron sputtering is 40W to 80W, the pressure is 0.2Pa to 3.0Pa, the time is 90s to 270s, and the target-substrate distance is 3.0cm to 10.0cm.

[0015] As a preferred embodiment of the present invention, the conductive particles include at least one of nano-silver particles, nano-copper particles, nano-nickel particles, and nano-tungsten particles.

[0016] As a preferred embodiment of the present invention, the thickness of the PET film is 0.15 to 0.25 mm;

[0017] The thickness of the hot melt film is 0.05-0.15 mm, and the hot melt film includes one of TPU film, PA film, PP film, and PE film.

[0018] As a preferred embodiment of the present invention, the fabric substrate is 100% polyester, the yarn count is 20D, the total density is 380T, and the weight is 40g / m 2 .

[0019] As a preferred embodiment of the present invention, the temperature of the first hot pressing is 120-150° C. and the time is 13-60 seconds;

[0020] The temperature of the second hot pressing is 120-150° C., and the time is 13-60 seconds.

[0021] As a preferred embodiment of the present invention, the power of the photolithography is 30-50%, the number of photolithography times is 1-10 times, the frequency is 15KHz-25KHz, and the speed is 2000mm / s-4000mm / s.

[0022] The present invention also provides the application of the stretchable flexible fabric circuit prepared by the above-described method in flexible electronic circuits and intelligent wearable sensors.

[0023] The beneficial effects of the present invention are: (1) the stretchable flexible fabric circuit described in the present invention is soft, breathable, resistant to bending, stretchable, has stable conductivity, and is washable. The electrodes and circuits can be integrated and patterned; (2) the stretchable flexible fabric circuit described in the present invention will not be damaged after multiple cycles of stretching, and the resistance change is small and can be restored; (3) the stretchable flexible fabric circuit described in the present invention will not be damaged after multiple cycles of bending, and the resistance change is small and can be restored; (4) the stretchable flexible fabric circuit described in the present invention can be applied to the fields of flexible electronic circuits and smart wearables. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart for preparing the stretchable flexible fabric circuit of the present invention;

[0025] Figure 2 This is a schematic diagram of the circuit structure of the stretchable flexible fabric according to the present invention;

[0026] Figure 3This is a resistance change curve of the stretchable flexible fabric circuit described in the present invention after cyclic stretching 200 times at 20% strain.

[0027] Figure 4 This is an electrical signal diagram of the stretchable flexible fabric circuit described in the present invention applied to a single-point fabric pressure sensor. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0030] In the present invention, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0031] In the present invention, unless otherwise stated, all parts are parts by mass.

[0032] The reagents and instruments used in the present invention without indicating the manufacturer are all conventional products that can be purchased from the market.

[0033] An embodiment of the present invention provides a method for preparing a stretchable flexible fabric circuit, comprising the following steps:

[0034] The elastic fabric is subjected to plasma treatment and then coated with a metal film on both sides of the elastic fabric by magnetron sputtering to obtain an elastic conductive fabric;

[0035] The PET film and the hot melt film are subjected to a first heat pressing, and then the fabric substrate is placed on the hot melt film and subjected to a second heat pressing to obtain a PET / fabric composite, and the PET / fabric composite is cut according to the circuit design pattern to obtain a mold;

[0036] Prepare two identical molds, place the elastic conductive fabric on the mold and fix it. After fixing it, place another identical mold on top of the elastic conductive fabric, and then place it on the photolithography platform. Perform double-sided photolithography along the designed circuit pattern to obtain a stretchable flexible fabric circuit.

[0037] Using vacuum sputtering physics technology, silver ions are combined with the fibers in the elastic fabric to produce an elastic conductive fabric. According to the designed circuit pattern, upper and lower photolithography composite fabric molds are made. The conductive fabric is placed flat between the upper and lower composite fabric molds, and the mold is positioned and fixed. The mold is then placed on the photolithography platform. The power of the photolithography equipment is set to 40%, the speed to 3000mm / s, and the frequency to 20kHz. A rectangular pattern with the overall photolithography area is imported and photolithography is performed on the front side. For reverse photolithography, simply turn the mold upside down, maintain the power and speed unchanged, and photolithograph the reverse side, finally obtaining a stretchable flexible fabric circuit.

[0038] The stretchable flexible fabric circuit is soft, breathable, resistant to bending, stretchable, has stable conductivity, and is washable. The electrodes and circuit can be integrated and patterned. The stretchable flexible fabric circuit survives multiple stretching cycles, exhibits minimal resistance change, and is recoverable. The stretchable flexible fabric circuit survives multiple bending cycles, exhibits minimal resistance change, and is recoverable.

[0039] Among them, the PET film mainly plays a reinforcing role on the mold and is easy to cut and pattern. The hot melt film mainly plays a role in bonding the fabric flatly to the PET film, acting as an adhesive. The fabric substrate mainly plays a role as a photoetching surface, protecting the PET film during multiple photoetching processes and preventing it from deformation.

[0040] The double-sided sputtering conductive layer of the elastic fabric can improve conductivity and stability, and a conductive path needs to be formed on the front and back sides; at the same time, the nylon yarn has good heat resistance, is not easily damaged during multiple photolithography, will not break brittlely, and does not affect its mechanical properties.

[0041] In one embodiment, the elastic fabric is woven from nylon and spandex in a loop manner, the nylon is 30D-50D nylon, the spandex is 20D-40D spandex, and the mass ratio of nylon to spandex is (75-85):(15-25).

[0042] In one embodiment, the elastic fabric has a gram weight of 80 g / m 2 ~120g / m 2 The thickness is 0.37mm~0.42mm, the longitudinal density is 200 pieces / 5cm~220 pieces / 5cm, and the transverse density is 115 pieces / 5cm~135 pieces / 5cm.

[0043] The elastic fabric under the above-mentioned parameters has good heat resistance, is not easily damaged during multiple photolithography, will not break brittlely, and does not affect the mechanical properties of the stretchable flexible circuit.

[0044] In one embodiment, the plasma treatment is performed in a plasma reaction vessel, the power of the plasma treatment is 250W to 350W, and the time is 200s to 400s.

[0045] In one embodiment, the magnetron sputtering uses conductive particles as target materials, the power of the magnetron sputtering is 40W to 80W, the pressure is 0.2Pa to 3.0Pa, the time is 90s to 270s, and the target-substrate distance is 3.0cm to 10.0cm.

[0046] In one embodiment, the conductive particles include at least one of nano-silver particles, nano-copper particles, nano-nickel particles, and nano-tungsten particles.

[0047] In one embodiment, the thickness of the PET film is 0.15 to 0.25 mm;

[0048] The thickness of the hot-melt film is 0.05 to 0.15 mm and includes one of TPU, PA, PP, and PE films. Controlling the thickness of the PET and hot-melt films within this range facilitates precise pattern processing and smooth cutting. Excessively thick film impedes precise pattern processing and requires multiple cuts, resulting in uneven edges.

[0049] In one embodiment, the fabric substrate is 100% polyester, the yarn count is 20D, the total density is 380T, and the weight is 40g / m 2 .

[0050] In one embodiment, the temperature of the first hot pressing is 120-150° C., and the time is 13-60 seconds;

[0051] The temperature of the second hot pressing is 120-150° C., and the time is 13-60 seconds.

[0052] In one embodiment, the power of the photolithography is 30-50%, the number of photolithography times is 1-10 times, the frequency is 15KHz-25KHz, and the speed is 2000mm / s-4000mm / s.

[0053] Another embodiment of the present invention provides the application of the stretchable flexible fabric circuit produced by the above method in flexible electronic circuits and smart wearable sensors.

[0054] Example 1

[0055] See also Figure 1, this embodiment provides a method for preparing a stretchable flexible fabric circuit, comprising the following steps:

[0056] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2 , thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0057] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0058] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0059] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 5 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first pumped to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 60 W, the sputtering pressure was 2 Pa, and the sputtering time was 180 s.

[0060] (4) A PET film with a thickness of 0.2 mm and a TPU hot melt film with a thickness of 0.15 mm were hot pressed at 135° C. for 30 seconds, and then a fabric substrate was laid on the TPU hot melt film and hot pressed at 135° C. for 30 seconds to obtain a PET / fabric composite; a cutting machine was used to cut two PET / fabric composite films of the same size and pattern according to the circuit design pattern, and when cutting, the circuit design pattern was cut until the PET / fabric composite was completely penetrated (i.e., the circuit design pattern was cut from the fabric substrate, the TPU hot melt film to the PET film until it was hollowed out), thereby obtaining two completely identical molds;

[0061] Overlap two identical molds face to face, align the patterns, fix the edges around them, and use a hole punch to punch holes at both ends for positioning.

[0062] (5) Place the PET film of one mold upward, lay the elastic conductive fabric flat on the PET film of the mold, and fix it around the four sides, then lay the PET film surface of another mold flat on the elastic conductive fabric, after the positioning holes are aligned, fix the edge of the mold, and after fixing, place it on the photolithography platform for double-sided photolithography, first perform photolithography on the front side, and uniformly set the photolithography pattern to a single rectangular pattern. The power of the photolithography equipment is set to 40%, the speed is 3000mm / s, the frequency is 20KHz, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1mm, and the conductive line width is 3mm. When performing photolithography on the reverse side, just turn the reverse side of the mold upward, keep the power and speed unchanged, and finally remove the mold to obtain a stretchable flexible fabric circuit. The structure of the prepared stretchable flexible fabric circuit is as shown in the figure. Figure 2 As shown, it includes an elastic fabric 1, an upper conductive layer 2 located above the elastic fabric, and a lower conductive layer located below the elastic fabric.

[0063] The multimeter test results show that the resistance between adjacent circuits is infinite, and the resistance of a single circuit is less than 50Ω.

[0064] As shown in Table 1, the initial resistance of the prepared stretchable flexible fabric circuit remains unchanged after being bent at 160°C for hundreds of times; its initial resistance remains almost unchanged after being stretched by 20% for hundreds of times, with good recovery and excellent stability.

[0065] Table 1 Effect of bending times on resistance

[0066] 160° bend 0 times 160° bending 100 times 160° bending 200 times 160° bending 500 times Resistance / Ω 14.6 14.6 14.6 14.6

[0067] The prepared stretchable flexible fabric circuit was washed and a magnetic stirrer was used to simulate washing conditions at a speed of 747 RPM. The resistance after 0 to 20 hours of simulated washing is shown in Table 2. It can be seen that the stretchable flexible fabric circuit has excellent water resistance and stability.

[0068] Table 2

[0069] Washing 0h Wash for 5 hours Washing 10 hours Washing 15h Washing 20h Resistance / Ω 14.6 14.6 14.7 14.9 14.9

[0070] Example 2

[0071] See also Figure 1 , this embodiment provides a method for preparing a stretchable flexible fabric circuit, comprising the following steps:

[0072] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2, thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0073] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0074] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0075] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 3 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first pumped to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 40 W, the sputtering pressure was 1 Pa, and the sputtering time was 90 s.

[0076] (4) A PET film with a thickness of 0.15 mm and a TPU hot melt film with a thickness of 0.1 mm were hot pressed at 135° C. for 30 seconds, and then a fabric substrate was placed on the TPU hot melt film and hot pressed at 135° C. for 30 seconds to obtain a PET / fabric composite; a cutting machine was used to cut two PET / fabric composite films of the same size and pattern according to the circuit design pattern, and when cutting, the circuit design pattern was cut until the PET / fabric composite was completely penetrated (i.e., the circuit design pattern was cut from the fabric substrate, the TPU hot melt film to the PET film until it was hollowed out), thereby obtaining two completely identical molds;

[0077] Overlap two identical molds face to face, align the patterns, fix the edges around them, and use a hole punch to punch holes at both ends for positioning.

[0078] (5) Place the PET film of one mold upward, lay the elastic conductive fabric flat on the PET film of the mold, and fix it on all sides. Then lay the PET film surface of another mold flat on the elastic conductive fabric. After the positioning holes are aligned, fix the edge of the mold. After fixing, place it on the photolithography platform for double-sided photolithography. The photolithography pattern is uniformly set to a single rectangular pattern. The power of the photolithography equipment is set to 50%, the speed is 2000mm / s, the frequency is 25KHz, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1mm, and the conductive line width is 3mm. When photolithography is performed on the reverse side, just turn the reverse side of the mold upward, keep the power and speed unchanged, and finally remove the mold to obtain a stretchable flexible fabric circuit.

[0079] Example 3

[0080] See also Figure 1 , this embodiment provides a method for preparing a stretchable flexible fabric circuit, comprising the following steps:

[0081] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2 , thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0082] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0083] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0084] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 10 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first evacuated to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 80 W, the sputtering pressure was 3 Pa, and the sputtering time was 270 s.

[0085] (4) A PET film with a thickness of 0.25 mm and a TPU hot melt film with a thickness of 0.1 mm were hot pressed at 135° C. for 30 seconds, and then a fabric substrate was laid on the TPU hot melt film and hot pressed at 135° C. for 30 seconds to obtain a PET / fabric composite; a cutting machine was used to cut two PET / fabric composite films of the same size and pattern according to the circuit design pattern, and when cutting, the circuit design pattern was cut until the PET / fabric composite was completely penetrated (i.e., the circuit design pattern was cut from the fabric substrate, the TPU hot melt film to the PET film until it was hollowed out), thereby obtaining two completely identical molds;

[0086] Overlap two identical molds face to face, align the patterns, fix the edges around them, and use a hole punch to punch holes at both ends for positioning.

[0087] (5) Place the PET film of one mold upward, lay the elastic conductive fabric flat on the PET film of the mold, and fix it around the four sides. Then lay the PET film surface of the other mold flat on the elastic conductive fabric. After the positioning holes are aligned, fix the edge of the mold. After fixing, place it on the photolithography platform for double-sided photolithography. The photolithography pattern is uniformly set to a single rectangular pattern. The power of the photolithography equipment is set to 30%, the speed is 4000mm / s, the frequency is 15KHz, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1mm, and the conductive line width is 3mm. When photolithography is performed on the reverse side, just turn the reverse side of the mold upward, keep the power and speed unchanged, and finally remove the mold to obtain a stretchable flexible fabric circuit.

[0088] Comparative Example 1

[0089] This comparative example provides a method for preparing a fabric circuit, comprising the following steps:

[0090] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2 , thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0091] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0092] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0093] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 5 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first evacuated to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 60 W, the sputtering pressure was 2 Pa, and the sputtering time was 180 s.

[0094] (4) The elastic conductive fabric is placed on a photolithography platform for single-sided photolithography (only one side is etched), with a photolithography power of 40%, a frequency of 20 kHz, a speed of 3000 mm / s, 5 photolithography times, a cross-line photolithography line type, a photolithography line width of 1 mm, and a conductive line width of 3 mm to obtain a fabric circuit.

[0095] Multimeter tests showed that the resistance between adjacent circuits was less than 10Ω, and the resistance of a single circuit was less than 10Ω. While etching only the front side of the elastic conductive fabric presented no alignment issues, it was not possible to form a flexible circuit. This is because the silver particles on the back side of the elastic conductive fabric are in contact with the front side, preventing an open circuit.

[0096] Comparative Example 2

[0097] This comparative example provides a method for preparing a fabric circuit, comprising the following steps:

[0098] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2 , thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0099] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0100] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0101] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 5 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first pumped to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 60 W, the sputtering pressure was 2 Pa, and the sputtering time was 180 s.

[0102] (4) The elastic conductive fabric is placed on a photolithography platform for double-sided photolithography. The front side is photolithographically processed first. The photolithography power is 40%, the frequency is 20 kHz, the speed is 3000 mm / s, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1 mm, the conductive line width is 3 mm, and the reverse side photolithography parameters are the same as the front side photolithography to obtain a fabric circuit.

[0103] Multimeter test results show infinite resistance between adjacent circuits, with resistance in the MΩ range for individual circuits. The front side of the elastic conductive fabric is patterned, while the back side is fully etched. While this preparation method improves the contact between the silver particles in Comparative Example 1, it still fails to form a flexible circuit. Because the silver particles on the back side of the elastic conductive fabric are fully etched, the silver particles on the front side of the conductive circuit will have poor contact, resulting in poor conductive stability and infinite resistance when stretched.

[0104] Comparative Example 3

[0105] This comparative example provides a method for preparing a fabric circuit, comprising the following steps:

[0106] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2 , thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0107] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0108] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0109] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 5 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first pumped to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 60 W, the sputtering pressure was 2 Pa, and the sputtering time was 180 s.

[0110] (4) using a cutting machine to cut two black-coated PET films of the same size and pattern and a thickness of 0.2 mm according to the circuit design pattern, and when cutting, cutting along the circuit design pattern until the PET film is completely penetrated (i.e., cutting the PET film along the circuit design pattern until it is hollowed out);

[0111] Overlap two identical molds face to face, align the patterns, fix the edges around them, and use a hole punch to punch holes at both ends for positioning.

[0112] (5) The elastic conductive fabric is laid flat on the PET film and fixed around it, and then another PET film is laid flat on the elastic conductive fabric. After the positioning holes are aligned, the edge of the mold is fixed. After fixing, it is placed on the photolithography platform for double-sided photolithography. The front side is photolithographically etched first. The photolithography pattern is uniformly set to a single rectangular pattern. The power of the photolithography equipment is set to 40%, the speed is 3000mm / s, the frequency is 20KHz, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1mm, and the conductive line width is 3mm. After 5 times of photolithography, the coating on the surface of the PET film is etched and becomes a transparent surface. The laser continues to etch the silver particles of the conductive fabric through the PET film, so that a patterned circuit cannot be formed.

[0113] Comparative Example 4

[0114] This comparative example provides a method for preparing a fabric circuit, comprising the following steps:

[0115] (1) 40D nylon and 40D spandex are weft-knitted into a plain elastic fabric, with a nylon content of 80wt%, a spandex content of 20wt%, a fabric longitudinal density of 210 strands / 5cm, a fabric transverse density of 125 strands / 5cm, and a gram weight of 100g / m 2 , thickness is 0.39mm, longitudinal stretching percentage is greater than 133%, and transverse stretching percentage is greater than 150%.

[0116] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0117] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0118] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 5 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first pumped to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 60 W, the sputtering pressure was 2 Pa, and the sputtering time was 180 s.

[0119] (4) using a cutting machine to cut two pure black PET films with the same size and pattern and a thickness of 0.2 mm according to the circuit design pattern, and when cutting, cutting along the circuit design pattern until the PET film is completely penetrated (i.e., cutting the PET film along the circuit design pattern until it is hollowed out);

[0120] Overlap two identical molds face to face, align the patterns, fix the edges around them, and use a hole punch to punch holes at both ends for positioning.

[0121] (5) The elastic conductive fabric is laid flat on the PET film and fixed around it, and then another PET film is laid flat on the elastic conductive fabric. After the positioning holes are aligned, the edge of the mold is fixed. After fixing, it is placed on the photolithography platform for double-sided photolithography. The front side is photolithographically etched first. The photolithography pattern is uniformly set to a single rectangular pattern. The power of the photolithography equipment is set to 40%, the speed is 3000mm / s, the frequency is 20KHz, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1mm, and the conductive line width is 3mm. After 5 times of photolithography, the surface of the PET film is damaged, severely deformed, and the alignment is offset, which affects the etching of the pattern and cannot be reused.

[0122] Comparative Example 5

[0123] A method for preparing a stretchable flexible fabric circuit comprises the following steps:

[0124] (1) 40s modal and 40D spandex are weft-knitted into a plain elastic fabric with a modal content of 90%, a spandex content of 10%, and a fabric weight of 180g / m 2 , thickness is about 0.55mm, longitudinal stretching percentage is 100%, and transverse stretching percentage is 100%.

[0125] (2) The elastic fabric is placed in a plasma reaction vessel for plasma treatment. The power of the plasma treatment is 300 W and the time is 260 s.

[0126] (3) using vacuum magnetron sputtering technology to plate nanosilver films on the front and back surfaces of the plasma-treated elastic fabric to obtain an elastic conductive fabric;

[0127] Among them, nanosilver is used as the target material in magnetron sputtering. The distance between the target material and the elastic fabric is 5 cm, the elastic fabric is on top and the target material is on the bottom. The reaction chamber is first pumped to a background vacuum of 8×10 -4 Pa, and then filled with 99.99% high-purity Ar gas as sputtering gas, the sputtering power was 60 W, the sputtering pressure was 2 Pa, and the sputtering time was 180 s.

[0128] (4) A PET film with a thickness of 0.2 mm and a TPU hot melt film with a thickness of 0.15 mm were hot pressed at 135° C. for 30 seconds, and then a fabric substrate was laid on the TPU hot melt film and hot pressed at 135° C. for 30 seconds to obtain a PET / fabric composite; a cutting machine was used to cut two PET / fabric composite films of the same size and pattern according to the circuit design pattern, and when cutting, the circuit design pattern was cut until the PET / fabric composite was completely penetrated (i.e., the circuit design pattern was cut from the fabric substrate, the TPU hot melt film to the PET film until it was hollowed out), thereby obtaining two completely identical molds;

[0129] Overlap two identical molds face to face, align the patterns, fix the edges around them, and use a hole punch to punch holes at both ends for positioning.

[0130] (5) Place the PET film of one mold upward, lay the elastic conductive fabric flat on the PET film of the mold, and fix it around the four sides. Then lay the PET film surface of the other mold flat on the elastic conductive fabric. After the positioning holes are aligned, fix the edge of the mold. After fixing, place it on the photolithography platform for double-sided photolithography. First, photolithography is performed on the front side. The photolithography pattern is uniformly set to a single rectangular pattern. The power of the photolithography equipment is set to 40%, the speed is 3000mm / s, the frequency is 20KHz, the number of photolithography times is 5, the photolithography line type is a cross line, the photolithography line width is 1mm, and the conductive line width is 3mm. When photolithography is performed on the reverse side, just turn the reverse side of the mold upward, keep the power and speed unchanged, and finally remove the mold to obtain a stretchable flexible fabric circuit.

[0131] Multimeter test results showed infinite resistance between adjacent circuits, and a single circuit resistance greater than 50Ω. The fabric substrate at the photoetched area was severely damaged, exhibiting poor mechanical properties. When stretched, the photoetched area easily fractured, and the circuit resistance reached levels exceeding kΩ.

[0132] Test Case

[0133] 1. The circuit resistance values ​​and the resistance values ​​between adjacent circuits of Example 1 and Comparative Examples 1 to 5 were tested using a multimeter, as shown in Table 1.

[0134] Table 1

[0135] Mold type Photolithography Circuit resistance / Ω Resistance between adjacent circuits / Ω Example 1 PET / fabric composite film Double-sided <15.0 >100000000 Comparative Example 1 none Single-sided <10.0 <10.0 Comparative Example 2 none Double-sided >1000000 >100000000 Comparative Example 3 Black coated PET film Double-sided >100000000 >100000000 Comparative Example 4 Black pure PET film Double-sided <15.0 <10000 Comparative Example 5 PET / fabric composite film Double-sided >1000 >1000000

[0136] 2. The stretchable flexible fabric circuit described in Example 1 was cyclically stretched 200 times at 20% strain, and the resistance change curve thereof is shown in FIG. Figure 3 shown.

[0137] 3. The stretchable flexible fabric circuit described in Example 1 was applied to a single-point fabric pressure sensor. The fabric pressure-sensitive layer was placed flat on the surface of the flexible fabric circuit and its edges were fixed to obtain a single-point fabric pressure sensor. The contact area between the flexible fabric circuit and the fabric pressure-sensitive layer was the fabric electrode, and the non-contact area was the fabric circuit. The greater the pressure, the smaller the output resistance. The fabric pressure sensor prepared with this fabric circuit has good linearity, and its electrical signal is shown in the following figure. Figure 4 shown.

[0138] 4. The stretchable flexible textile circuit described in Example 1 was applied to a textile pressure sensor array. The upper flexible textile circuit, the textile pressure-sensitive layer, and the lower flexible textile circuit were overlapped and their edges were fixed to form the textile pressure sensor array. The upper and lower flexible textile circuits were arranged perpendicularly. The contact areas between the flexible textile circuit and the textile pressure-sensitive layer served as textile electrodes, while the non-contact areas served as the textile circuit. The greater the pressure, the smaller the output resistance.

[0139] In summary, the stretchable flexible fabric circuit prepared by the present invention is soft, breathable, resistant to bending, stretchable, has stable conductivity, and is resistant to washing. The electrodes and circuits can be integrated and patterned. It will not be damaged after multiple cycles of stretching, and the resistance changes little and can be restored. It will not be damaged after multiple cycles of bending, and the resistance changes little and can be restored.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a stretchable flexible fabric circuit, characterized in that: The following steps are involved: The elastic fabric is subjected to plasma treatment and then coated with a metal film on both sides of the elastic fabric by magnetron sputtering to obtain an elastic conductive fabric; The PET film and the hot melt film are subjected to a first heat pressing, and then the fabric substrate is placed on the hot melt film and subjected to a second heat pressing to obtain a PET / fabric composite, and the PET / fabric composite is cut according to the circuit design pattern to obtain a mold; Prepare two identical molds, place the elastic conductive fabric on the mold, fix it, and then place another identical mold on top of the elastic conductive fabric. Then place it on a photolithography platform and perform double-sided photolithography along the designed circuit pattern to obtain a stretchable flexible fabric circuit. The elastic fabric is woven from nylon and spandex in a loop-forming manner, wherein the nylon is 30D-50D nylon, the spandex is 20D-40D spandex, and the mass ratio of the nylon to the spandex is (75-85):(15-25); The elastic fabric has a gram weight of 80 g / m 2 ~120g / m 2 The thickness is 0.37mm~0.42mm, the longitudinal density is 200 pieces / 5cm~220 pieces / 5cm, and the transverse density is 115 pieces / 5cm~135 pieces / 5cm.

2. The method for preparing a stretchable flexible fabric circuit according to claim 1, wherein: The plasma treatment is carried out in a plasma reaction container, the power of the plasma treatment is 250W to 350W, and the time is 200s to 400s.

3. The method for preparing a stretchable flexible fabric circuit according to claim 1, wherein: The magnetron sputtering uses conductive particles as target materials, the power of the magnetron sputtering is 40W to 80W, the pressure is 0.2Pa to 3.0Pa, the time is 90s to 270s, and the target-substrate distance is 3.0cm to 10.0cm; The conductive particles include at least one of nano-silver particles, nano-copper particles, nano-nickel particles, and nano-tungsten particles.

4. The method for preparing a stretchable flexible fabric circuit according to claim 1, wherein: The thickness of the PET film is 0.15 to 0.25 mm; The thickness of the hot melt film is 0.05-0.15 mm, and the hot melt film includes one of TPU film, PA film, PP film, and PE film.

5. The method for preparing a stretchable flexible fabric circuit according to claim 1, wherein: The fabric base material is 100% polyester, the yarn count is 20D, the total density is 380T, and the weight is 40g / m 2 .

6. The method for preparing a stretchable flexible fabric circuit according to claim 1, wherein: The temperature of the first hot pressing is 120-150° C. and the time is 13-60 seconds; The temperature of the second hot pressing is 120-150° C., and the time is 13-60 seconds.

7. The method for preparing a stretchable flexible fabric circuit according to claim 1, wherein: The power of the photolithography is 30-50%, the number of photolithography times is 1-10 times, the frequency is 15KHz-25KHz, and the speed is 2000mm / s-4000mm / s.

8. Application of the stretchable flexible fabric circuit prepared by the method according to any one of claims 1 to 7 in flexible electronic circuits and smart wearable sensors.

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