Network strain sensing composite yarn and preparation method and application thereof

Abstract

The application relates to a network-shaped strain sensing composite yarn and a preparation method and application thereof, and belongs to the technical field of intelligent textiles. The preparation method comprises the following steps: S1, a conductive material is wrapped around the surface of an elastic yarn in a ring twining manner to obtain a conductive elastic yarn; the elastic yarn is kept in a stretched state during the wrapping process; S2, polytetrafluoroethylene yarn is knitted on the surface of the conductive elastic yarn to obtain the network-shaped strain sensing composite yarn; the conductive elastic yarn is kept in a stretched state during the knitting process. After the yarn is taken off, the polytetrafluoroethylene yarn on the surface forms a fluffy network structure due to the disappearance of tension. The network-shaped strain sensing composite yarn has excellent sensitivity and reliable stability during the stretching and recovery process. The protective fabric prepared from the network-shaped strain sensing composite yarn solves the defect of poor comfort of traditional protective materials, and has the functions of protection, movement monitoring, intelligent early warning and heat and moisture comfort.

Description

Technical Field

[0001] This invention belongs to the field of intelligent textile technology, and particularly relates to a network-like strain-sensing composite yarn, its preparation method, and its application. Background Technology

[0002] Protective textiles refer to clothing or textiles with protective properties, whose primary function is protection rather than decoration. Textiles used for personal protection can be categorized based on their application, such as medical protective textiles, agricultural protective textiles, and sports protective textiles. Among various hazards, protection against chemicals is currently considered the most critical issue. Chemical protective clothing is widely used in industrial chemical production, chemical warfare, and laboratory experiments. The main component of chemical protective clothing is the protective material. Due to the impermeability of these materials, they hinder the transmission of sweat and moisture, making it difficult for most protective materials to achieve breathability and moisture permeability. However, excessive breathability and moisture permeability often lead to poor protection. Therefore, it is difficult to strike a balance between protection and breathability / moisture permeability in chemical protective materials.

[0003] Furthermore, with the development of the Internet of Things and artificial intelligence technologies, the future of protective materials is also moving towards intelligence. Traditional protective materials are gradually failing to meet people's needs, and only intelligent protective materials with special functions can meet the needs of future society. Intelligent chemical protective materials should possess excellent protective properties, accurate human motion monitoring, intelligent early warning of hazardous substances, and thermal and humidity comfort.

[0004] Therefore, researching and developing a composite yarn that combines strain sensing, acid and alkali protection, intelligent early warning, and thermal and humidity comfort is of great value and significance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a network-like strain-sensing composite yarn, its preparation method, and its application.

[0006] The first objective of this invention is to provide a method for preparing a network-like strain-sensing composite yarn, comprising the following steps:

[0007] S1. Conductive material is wrapped around the surface of elastic yarn by ring twisting to obtain conductive elastic yarn; the elastic yarn is kept in a stretched state during the wrapping process.

[0008] S2. Polytetrafluoroethylene yarn is woven on the surface of the conductive elastic yarn described in S1 to obtain the network-like strain sensing composite yarn; the conductive elastic yarn is kept in a stretched state during the weaving process.

[0009] In one embodiment of the present application, in S1, the conductive material is one or more of silver-plated nylon yarn, silver-plated polyester yarn and metal nanowire; the fineness of the conductive material is one or more of 100D, 140D, 200D and 280D.

[0010] In one embodiment of the present application, in S1, the stretch yarn is one or more of spandex, polyester filament and rubber filament.

[0011] In one embodiment of the present application, in S1, the ring twister has a spindle speed of 4100-4300 r / min and an output linear speed of 7-10 m / min.

[0012] In one embodiment of the present application, in S2, the polytetrafluoroethylene yarn has a fineness of one or more of 1000D, 1250D and 1350D.

[0013] In one embodiment of the present application, in S2, the number of spindles in the braiding process is 8 or 16.

[0014] In one embodiment of the present application, in S1 and S2, the stretch to the normal state is 110-150%.

[0015] A second object of the present application is to provide a network-shaped strain sensing composite yarn prepared by the method.

[0016] A third object of the present application is to provide a fabric prepared from the network-shaped strain sensing composite yarn.

[0017] A fourth object of the present application is to provide the use of the fabric in chemical protection and intelligent early warning.

[0018] The technical solution of the present application has the following advantages compared with the prior art:

[0019] (1) The network-shaped strain sensing composite yarn has good tensile properties, and as the network-shaped strain sensing composite yarn is stretched, the resistance of the high-elastic conductive material inside also changes, thereby realizing the monitoring of human body movements when the network-shaped strain sensing composite yarn is attached to the joints of the human body.

[0020] (2) The network strain sensing composite yarn outer layer of the present application is knitted by PTFE yarn. After the yarn is taken off the machine, the surface layer of polytetrafluoroethylene yarn forms a fluffy network structure due to the disappearance of tension. The knitted structure is characterized by a surface full of holes and large stretching. The holes ensure the entry and exit of water vapor, thereby realizing the thermal and moisture comfort of the protective material. Although the surface of the knitted structure is full of pores, the low surface tension of the PTFE yarn can also prevent liquid from entering. At the same time, the knitted structure can also stretch when stretched.

[0021] (3) The network strain sensing composite yarn outer layer of the present application is PTFE yarn. Due to the good chemical stability and low surface tension of PTFE yarn, the chemical stability of PTFE yarn can realize the protection of common acid and alkali solutions, and the low surface tension realizes the hydrophobicity of chemical solutions. Due to the acid and alkali resistance, flame resistance and hydrophobicity of PTFE yarn, the network strain sensing composite yarn has acid and alkali resistance and hydrophobicity when woven into fabric, thereby achieving the purpose of solution impermeability and resistance to acid and alkali solution corrosion.

[0022] (4) The network strain sensing composite yarn of the present application is a single electrode triboelectric nanogenerator itself. The outer layer of PTFE yarn is the negative electrode material of the triboelectric nanogenerator, and the human skin or liquid droplets are the complete machine of the single electrode triboelectric nanogenerator. The internal high-elastic conductive material serves as the wire of the single electrode triboelectric nanogenerator to connect the positive and negative electrodes. When different liquid droplets contact the network strain sensing composite yarn, different electric signals are generated, thereby realizing the intelligent early warning of the intelligent protective material.

[0023] (5) The network strain sensing composite yarn of the present application produces different sizes of holes when subjected to different stretching, which makes the fabric woven by the network strain sensing composite yarn produce different holes when subjected to different stretching, thereby avoiding the shortcomings of traditional protective materials such as stuffiness and poor air permeability, and achieving the combination of protection and thermal and moisture comfort.

[0024] (6) The network strain sensing composite yarn of the present application not only has excellent sensitivity but also has reliable stability during the stretching and recovery process. The protective fabric prepared by using the network strain sensing composite yarn solves the shortcomings of traditional protective materials such as poor comfort, and has the functions of protection, motion monitoring, intelligent early warning and thermal and moisture comfort. The method of the present application is simple to operate, low in production cost, and has the potential for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings, in which:

[0026] Figure 1Preparation flow chart of the network strain sensing composite yarn of the embodiment 1 of the present application.

[0027] Figure 2 Relative resistance change value of the network strain sensing composite yarn with different twist in the test example 1 of the present application at different stretching.

[0028] Figure 3 Sensitivity of the 40T network strain sensing composite yarn in the test example 1 of the present application at different stretching.

[0029] Figure 4 Change chart of the network strain sensing composite yarn fabric, cotton fabric after contacting with NaOH and H2SO4 in the test example 2 of the present application.

[0030] Figure 5 Air permeability and water vapor transmission rate of the network strain sensing composite yarn fabric along the weft direction at different stretching in the test example 3 of the present application.

[0031] Figure 6 40T network strain sensing composite yarn is pasted on the knee in the test example 4 of the present application, and the electrical signal generated by the knee bending at different walking speeds is collected.

[0032] Figure 7 40T network strain sensing composite yarn is pasted on the wrist in the test example 4 of the present application, and the electrical signal generated by shaking the cup with the wrist is collected.

[0033] Figure 8 Network strain sensing composite yarn fabric is contacted and separated with droplets with different volumes in the test example 5 of the present application, and the electrical signal generated is collected.

[0034] Figure 9 Network strain sensing composite yarn fabric is contacted and separated with droplets with different speeds in the test example 5 of the present application, and the electrical signal generated is collected. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting to the present application.

[0036] Embodiment 1

[0037] Referring to Figure 1 A network strain sensing composite yarn and a preparation method thereof are shown in the drawings, which specifically comprises the following steps:

[0038] Preparation of conductive elastic yarn: Conductive elastic yarn is prepared using 100D silver-plated nylon yarn (conductive yarn). Spandex and silver-plated nylon yarn packages are placed on the bobbin support of a ring twisting machine. The spandex package is unwound and passed through a yarn guide and tensioner to stretch it to 150% of its original length. It is then fed into the front roller nip of the ring twisting machine at the front roller and upper pressure roller. The silver-plated nylon yarn package is unwound and fed into the front roller nip of the ring twisting machine via a yarn guide, where it merges with the spandex at the front roller nip. The merged spandex and silver-plated nylon yarn are then output from the roller nip. The output linear speed is 7 m / min. The output spandex and silver-plated nylon yarns are subjected to ring twisting and winding. The spindle speed during ring twisting and winding is 4250 r / min. The ring twisting force three-dimensionally twists the silver-plated nylon yarn, causing the silver-plated nylon yarn to be directly and tightly wound on the spandex to form a conductive elastic yarn. The formed high-elasticity conductive yarn is wound onto the yarn tube. The ring twisting force three-dimensionally twists the silver-plated nylon yarn, causing the silver-plated nylon yarn to be directly and tightly wound on the spandex to form a conductive elastic yarn. The final high-elasticity silver-plated nylon yarn has a twist of 40T, denoted as 40T. Finally, the conductive elastic yarn is wound onto the yarn tube.

[0039] Preparation of network-like strain-sensing composite yarn: 1250D PTFE yarn is wound onto the spindles of a rope braiding machine using a winding machine (8 spindles). The conductive elastic yarn is stretched to 150% of its original length. The spindles containing the PTFE yarn are sequentially placed into a yarn carrier, and then the PTFE yarn is passed through the holes of the yarn carrier and fixed to the central shaft. High-elastic conductive yarns of different twists are passed through a tensioner from the bottom of the braiding machine through a circular bobbin and fixed to the central shaft, merging with the PTFE yarn. After the braiding machine is started, the PTFE yarn on the yarn carrier is woven onto the outer layer of the high-elastic conductive yarn through figure-eight and figure-O rotational movements, thus forming a network-like strain-sensing composite yarn. The prepared network-like strain-sensing composite yarn is drafted and wound onto a bobbin using a drafting device, and is designated as 40T network-like strain-sensing composite yarn.

[0040] Test Example 1

[0041] (1) Testing the network-like strain-sensing composite yarn of Example 1 in

[0042] Based on Example 1, 10T, 20T, 30T, 40T, and 50T network strain sensing composite yarns were prepared. The changes in electrical signals under different twists were tested. Specifically, the following steps were included: network strain sensing composite yarns of different twists were placed on a moving slide table, and a digital multimeter was connected to one end of each yarn. The yarns were stretched to 50% of their original length at a speed of 200 mm / min. The results are as follows... Figure 2 As shown. From Figure 2It can be seen that the relative change of resistance of the 40T network strain sensing composite yarn is the largest, which can reach 80%. Too large twist leads to the failure of the conductive yarn to separate in time during stretching, while too small twist leads to excessive separation during stretching and cannot provide a larger resistance change.

[0043] (2) The sensitivity of the 40T network strain sensing composite yarn of Example 1 at different stretching was tested, specifically including the following steps: the 40T network strain sensing composite yarn was placed on a moving slide, and a digital multimeter was connected to one end of the network strain sensing composite yarn, and the polyimide hollow composite yarn strand was stretched to 50% of the original length at a speed of 200 mm / min, and the results are shown in Table 3. From Figure 3 It can be seen that the sensitivity of the 40T network strain sensing composite yarn is the largest, which is 5.9.

[0044] It can be seen that the network strain sensing yarn has excellent strain sensing performance and can accurately monitor the motion changes of the human body in real time.

[0045] Test Example 2

[0046] Based on Example 1, the network strain sensing composite yarn was woven into a fabric and a cotton fabric, and the state in different chemical solutions was tested, specifically including the following steps:

[0047] A plain weave structure diagram was set on a sample loom. The PTFE yarn was wound 30 turns on the warping beam, and after the winding was finished, the PTFE yarn was cut and fixed on the cloth ring behind the loom. A certain length of warp yarn was wound on the warp beam, leaving enough warp yarn to pass through the front of the loom.

[0048] The warp yarn was sequentially threaded through the harnesses using a threading hook, and then the warp yarn was threaded through the reed. In order to ensure that the woven fabric has good tensile properties, the PTFE yarn is threaded through every 8 reeds. After the PTFE yarn is threaded through the reed, it is straightened, and the tension of each PTFE yarn is kept uniform before being tied to the cloth ring of the cloth roller.

[0049] The network strain sensing composite yarn was wound on a pirn, the machine was started, the loom lifted the harness frame to open the warp yarn up and down, and the pirn was threaded through the warp yarn opening during the opening process. The network strain sensing composite yarn was kept in a stretched state during beating-up, so that the length of the network strain sensing composite yarn was 50% of the original length. Finally, a 40T network strain sensing composite yarn fabric of 10*10 cm was prepared.

[0050] NaOH solution with a concentration of 60% and H2SO4 solution with a concentration of 98% were dropped on the surface of the network strain sensing composite yarn fabric and the cotton fabric respectively, and a microscope was used to observe the surface changes, and the results are shown in Table 4. Figure 4The cotton fabric has been corroded by NaOH and H2SO4 solution, but the surface of the network strain sensing composite yarn fabric is still unchanged. This proves that the network strain sensing composite yarn fabric has good chemical resistance.

[0051] Test Example 3

[0052] The network strain sensing composite yarn fabric prepared in Test Example 2 was subjected to air permeability and thermal conductivity tests, which included the following steps:

[0053] The network strain sensing composite yarn fabric was placed in the fabric air permeability tester and the water vapor permeability tester, respectively. The air permeability of the network strain sensing composite yarn fabric with an area of 20 cm 2 was tested under a pressure of 200 Pa to obtain the air permeability of the network strain sensing composite yarn fabric at different stretching percentages; the water vapor permeability of the network strain sensing composite yarn at various stretching percentages was tested by the upright cup method, wherein the sample size was 25 cm 2 , the temperature was 38±0.6℃, and the relative humidity was 90±2%, and the results are shown in Figure 5 .

[0054] As can be seen from Figure 5 , as the stretching increases, the air permeability and water vapor permeability of the network strain sensing composite yarn fabric also gradually increase, because as the stretching increases, the network strain sensing composite yarn in the fabric is gradually stretched and thinned, resulting in an increase in the spacing between the weft yarns and the gap, thereby increasing the air permeability and water vapor permeability of the network strain sensing composite yarn fabric as the stretching increases. Figure 5 The network strain sensing composite yarn fabric exhibits good air permeability and moisture permeability characteristics as it is stretched under stress.

[0055] Test Example 4

[0056] The 40T network strain sensing composite yarn of Example 1 was attached to different parts of the body to monitor human movement, which included the following steps:

[0057] The 40T network strain sensing composite yarn was attached to the knee, and the electrical signals generated by the knee bending at different walking speeds were collected, and the results are shown in Figure 6 . As can be seen from Figure 6 , the network strain sensing composite yarn can produce corresponding changes in electrical signals for different actions (fast walking, slow walking, normal walking).

[0058] The 40T network strain sensing composite yarn was attached to the wrist, and the electrical signals generated by the wrist shaking the cup were collected, and the results are shown in Figure 7 . As can be seen from Figure 7It can be seen that the network-like strain sensing composite yarn has excellent sensing ability for bending. When the beaker is shaken, the greater the bending angle, the greater the change in relative resistance.

[0059] In summary, the network-like strain-sensing composite yarn can generate a change in relative resistance with tensile recovery, thereby enabling the monitoring of human movement. The network-like strain-sensing composite yarn has excellent performance in human movement monitoring, can achieve accurate human movement monitoring, and has broad application prospects.

[0060] Test Example 5

[0061] The network-like strain-sensing composite yarn fabric serves both as a strain sensing device and a single-electrode triboelectric nanogenerator. The weft yarns of this fabric are network-like strain-sensing composite yarns, with the outer layer being PTFE yarn that acts as the negative electrode in the triboelectric nanogenerator, and the inner conductive elastic yarn serving as the conductor. Human skin or liquid droplets act as the positive electrode in the triboelectric nanogenerator.

[0062] Test Example 2 was used to test the electrical signal generated when a 10*10cm 40T network strain-sensing composite yarn fabric came into contact with and separated from a liquid droplet. The network strain-sensing composite yarn fabric was connected to both ends of an electrometer. Water droplets of different volumes were dropped onto the surface of the network strain-sensing composite yarn fabric using a pipette. The test results are as follows. Figure 8 As shown in the figure. Then, water droplets were dropped onto the surface of the network-like strain-sensing composite yarn fabric at different frequencies, and the test results are as follows. Figure 9 As shown. (Through) Figures 8-9 This demonstrates that the network-like strain-sensing composite yarn fabric has the potential to provide early warning of droplets.

[0063] The basic principle of the network-like strain-sensing composite yarn fabric used as a single-electrode triboelectric nanogenerator is:

[0064] When human skin or droplets come into contact with the PTFE yarn on the outer layer of the network strain sensing composite fabric, equal amounts of positive and negative charges are generated on the human skin or droplets and the PTFE yarn surface due to triboelectric charging. Human skin or droplets lose electrons more easily than PTFE yarn and thus become positively charged.

[0065] When human skin or a droplet separates from the PTFE yarn on the outer layer of the network strain-sensing composite fabric, electrons gradually flow from the fabric to the ground due to electrostatic induction, thereby balancing the potential difference between the human skin or droplet and the PTFE yarn.

[0066] When human skin or a droplet comes into complete contact with PTFE yarn, the charges on both surfaces are completely neutralized, so there is no current in the circuit at this time.

[0067] When the human skin or the droplet contacts the PTFE yarn again, the electrons flow back to the electrode from the ground.

[0068] The above is a complete cycle of the single-electrode triboelectric nanogenerator generating electrical signals. The cyclic flow of electrons between the two materials generates positive and negative electrical pulses. When there is a continuous cycle of contact and separation, the periodic charge transfer between the positive and negative electrodes generates alternating voltage and current.

[0069] Obviously, the above-mentioned embodiments are only examples for the purpose of clarity and are not intended to limit the embodiments. Based on the above description, those skilled in the art can make other different forms of changes or variations. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing a network-like strain-sensing composite yarn, characterized in that, Comprising the following steps, S1, wrapping the conductive material on the surface of the elastic yarn by ring twisting to obtain the conductive elastic yarn; the elastic yarn is kept in the stretched state during the wrapping process; S2, weaving the polytetrafluoroethylene yarn on the surface of the conductive elastic yarn obtained in S1 to obtain the network-like strain sensing composite yarn; the conductive elastic yarn is kept in the stretched state during the weaving process; In S1 and S2, the stretched state is stretched to 110-150% of the normal state.

2. The method of claim 1, wherein the networked strain sensing composite yarn is prepared by the steps of: In S1, the conductive material is one or more of silver-plated nylon yarn, silver-plated polyester yarn and metal nanowire; the fineness of the conductive material is one or more of 100D, 140D, 200D and 280D.

3. The method of claim 1, wherein the networked strain sensing composite yarn is prepared by the steps of: In S1, the elastic yarn is one or more of spandex, polyester filament and rubber filament.

4. The method of claim 1, wherein the networked strain sensing composite yarn is prepared by the steps of: In S1, the spindle speed of the ring twisting is 4100-4300 r / min, and the output linear speed is 7-10 m / min.

5. The method of claim 1, wherein the networked strain sensing composite yarn is prepared by the steps of: In S2, the fineness of the polytetrafluoroethylene yarn is one or more of 1000D, 1250D and 1350D.

6. The method of claim 1, wherein the networked strain sensing composite yarn is prepared by the steps of: In S2, the number of spindles during the weaving process is 8 or 16.

7. The network-like strain sensing composite yarn prepared by the method of any one of claims 1-6.

8. A fabric, characterized by The fabric is prepared from the network-like strain sensing composite yarn of claim 7.

9. The use of the fabric of claim 8 in chemical protection and intelligent early warning.

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