Preparation method of flame-retardant friction nanometer power generation fabric with perfluoro friction outer layer

Abstract

The invention provides a preparation method of a flame-retardant friction nanometer power generation fabric with a perfluoro friction outer layer, and belongs to the technical field of intelligent textiles. According to the fabric, the silver-plated nylon yarn serves as a conductive inner core, the outer side of the silver-plated nylon yarn is tightly wrapped with the PTFE filament through a high-speed weaving technology to form an outer friction layer, composite yarn of a skin-core structure is prepared, and finally the flame-retardant friction nanometer power generation fabric is woven. And the fabric shows excellent cycle work stability and washing resistance, and is high in air and moisture permeability and good in comfort.

Description

Technical Field

[0001] The invention belongs to the technical field of intelligent textiles, and in particular relates to a method for preparing a flame-retardant friction nano-electricity generating fabric with a perfluorinated friction outer layer. Background Art

[0002] In the early stage of the development of smart textiles, rigid electronic devices were directly integrated into flexible textiles through sewing, weaving and other methods. With the continuous development of technology, rigid electronic devices have gradually transformed into textile electronic devices based on fibers, yarns or fabrics or directly digitized such materials, which has promoted the rapid development of flexible smart textiles. Smart textiles are an important branch of the wearable field. In recent years, smart textiles have shown great application potential in the fields of human body sensing, artificial intelligence, medical bionics, etc., and will provide unlimited possibilities for human motion monitoring, health testing, etc., so they have received widespread attention from domestic and foreign academic circles. Compared with sensing devices such as smart bracelets, smart glasses, and smart skin, smart wearable fabrics have unique advantages such as light weight, high softness and elasticity, low cost, high skin affinity, comfort, and long-term use. Therefore, they are very popular in the field of wearable smart sensing materials, and the research on smart wearable fabrics is also receiving more and more attention.

[0003] After Professor Wang Zhonglin proposed the concept of friction nanogenerator (TENG), researchers combined TENG with traditional textiles to develop friction nanogenerator fabrics (T-TENG). T-TENG has both the piezoelectric effect of TENG and the softness, breathability and comfort of textiles, and has outstanding application prospects in the fields of smart textiles and smart wearables. Patent CN115948851A discloses a warp knitted terry smart fabric based on a friction nanogenerator and its application. The warp knitted terry smart fabric includes a fabric velvet surface in contact with external substances and a fabric base fabric that is not in contact with external substances. The fabric velvet surface is the friction electrification layer of the warp knitted terry smart fabric, and the fabric base fabric is the conductive layer and support layer of the warp knitted terry smart fabric; the fabric combines the mature warp knitting process with the emerging friction nanogenerator, giving full play to the advantages of both. Compared with traditional wearable smart products, the warp knitted terry smart fabric provided by this application is more flexible and breathable while meeting the requirements of self-powered sensing and monitoring, and is more comfortable to wear, and avoids the problem of power supply safety of traditional wearable smart products. Patent CN109104117A discloses a wearable fabric nanogenerator and its preparation method. A conductive yarn is prepared by adding a coating layer on the surface of pure cotton yarn by chemical electroplating. The conductive core yarn is used as the core yarn. The yarn coated with nanofibers is prepared by conjugated electrostatic spinning technology. Then, the two core-spun yarns are woven separately to form a single-layer nanofiber fabric by weaving. The two fabric layers are then connected by ultra-fine transparent nylon, and the corresponding air layer is left to finally obtain a wearable fabric nanogenerator. Nanogenerators can convert mechanical energy, especially low-frequency body kinetic energy, into electrical energy. Due to its environmental protection and universal availability, they are used in collecting small mechanical energy and large-scale energy generation.

[0004] However, most of the current friction nano-power generation fabrics are not flame retardant and are easily damaged in fires, losing their ability to supply power. In addition, their mechanical properties and wearing comfort need to be further improved. Therefore, it is crucial to design flame retardant friction nano-power generation fabrics. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art and provide a method for preparing a flame-retardant friction nano-power generation fabric with a perfluorinated-based friction outer layer. The fabric uses silver-plated nylon yarn as a conductive inner core. Through a high-speed weaving process, polytetrafluoroethylene (PTFE) filaments are tightly wrapped around the outside of the silver-plated nylon yarn to form an outer friction layer, thereby obtaining a composite yarn with a skin-core structure. The method is simple, and the resulting fabric has ultra-high flame retardancy, smoke suppression, and anti-dripping properties, and excellent electrical output performance.

[0006] In order to solve the above technical problems, the technical solution of the present invention is:

[0007] In one aspect, a composite yarn comprises an inner core of silver-plated nylon filaments and an outer friction layer; wherein the outer friction layer is PTFE filaments or a PTFE coating.

[0008] Furthermore, the fineness of the silver-plated nylon filament is 20-200D, preferably 20-100D.

[0009] Furthermore, the fineness of the PTFE filament is 300-600D, preferably 400-500D.

[0010] Furthermore, the PTFE coating contains PTFE and a solvent; the solvent is water or a mixture of ethanol and water, preferably water.

[0011] Furthermore, the mass fraction of PTFE in the PTFE coating is 30-70%, preferably 40-50%.

[0012] Furthermore, in order to improve the comprehensive performance of the composite yarn, the PTFE coating also includes an auxiliary agent, which is selected from at least one of a conductive nanofiller, a dispersant, a surfactant, and a silane coupling agent; wherein the conductive nanofiller includes but is not limited to carbon black, carbon nanotubes, graphene and silver nanoparticles; the dispersant includes but is not limited to silicates, alkali metal phosphates, triethylhexyl phosphoric acid, sodium dodecyl sulfate, methylpentanol, cellulose derivatives, polyacrylamide, guar gum or fatty acid polyethylene glycol esters; the surfactant includes but is not limited to stearic acid, sodium dodecylbenzene sulfonate, lecithin, betaine type zwitterionic surfactants, alkyl glucoside, fatty acid glyceride, fatty acid sorbitan or polysorbate; the silane coupling agent includes but is not limited to vinyl triethoxysilane, vinyl trimethoxysilane, aminopropyl methyl diethoxysilane, γ-diethylenetriamine propyl methyl dimethoxysilane or N-aminoethyl-3-aminopropyl methyl dimethoxysilane.

[0013] Furthermore, the mass fraction of the auxiliary agent in the PTFE coating is 0.1-30%, preferably 5-20%.

[0014] On the other hand, the method for preparing the composite yarn,

[0015] When the outer friction layer is PTFE filaments, the method comprises the following steps:

[0016] First, the PTFE filaments are pre-wound on the matching yarn tubes, and the silver-plated nylon filaments are wound on the special bobbin in the middle of the high-speed braiding machine, and fed axially from the bottom of the track disk, and the gear transmission ratio is set to start braiding; during the braiding process, the PTFE filaments are evenly divided into two groups, one group rotates clockwise and the other group rotates counterclockwise, so that the PTFE filaments are woven into a dense outer friction layer on the outside of the silver-plated nylon filaments, thereby obtaining a composite yarn with a skin-core structure;

[0017] When the outer friction layer is a PTFE coating, the method comprises the following steps:

[0018] The additive is dispersed in the PTFE aqueous solution to form a composite dispersion, and then the silver-plated nylon filament is immersed in the composite dispersion to obtain a composite yarn with the PTFE coating as the outer friction layer.

[0019] Furthermore, the immersion temperature is 20-40°C, and the immersion time is 5-20s; preferably, the immersion temperature is 30-35°C, and the immersion time is 10-15s.

[0020] Furthermore, the number of immersion treatments is 2-6 times, and preferably the number of immersion treatments is 3-5 times.

[0021] In the present invention, the gear transmission ratio of the high-speed braiding machine refers to the ratio between the yarn collection speed and the interweaving speed. In order to obtain composite yarns and fabrics with better mechanical properties, flame retardant properties and electrical output performance, a gear transmission ratio of 0.3-0.5 is selected for weaving, and a gear transmission ratio of 0.3-0.35 is preferably selected.

[0022] On the other hand, a flame-retardant friction nano-power generation fabric with a perfluorinated friction outer layer is woven from the above-mentioned composite yarn.

[0023] Beneficial effects:

[0024] (1) The present invention provides a composite yarn with a core-skin structure, which has a silver-plated nylon yarn as a conductive inner core and a PTFE filament as an outer friction layer. The composite yarn is woven by high-speed weaving technology, and the PTFE filaments are tightly wrapped around the outside of the silver-plated nylon yarn, so that the obtained composite yarn has a compact structure. The fabric woven by machine using the composite yarn not only has excellent flame retardancy, smoke suppression, and anti-melting droplet properties, but also has excellent electrical output performance, and also exhibits excellent cycle working stability and water washability, high air permeability and moisture permeability, and good comfort.

[0025] (2) The present invention helps to improve the mechanical properties, flame retardant properties and electrical output properties of the composite yarn and fabric by controlling the gear transmission ratio of the high-speed braiding machine during the composite yarn preparation process.

[0026] (3) The present invention helps to improve the performance of the composite yarn by optimizing the fineness of the PTFE filaments in the composite yarn, thereby improving the mechanical properties, flame retardant properties and electrical output performance of the fabric.

[0027] (4) The composite yarn with a skin-core structure provided by the present invention has a silver-plated nylon yarn as a conductive inner core and a PTFE coating as an outer friction layer. The fabric woven by using the composite yarn has excellent mechanical properties, flame retardant properties and electrical output performance. Adding a certain amount of additives to the PTFE coating helps to further improve the mechanical properties, flame retardant properties and electrical output performance of the fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of high-speed weaving of a composite yarn according to Example 1 of the present invention;

[0029] Figure 2 1 is a SEM image of the composite yarn of Example 1 of the present invention; in the image, (a) is a surface image, and (b) is a cross-sectional image;

[0030] Figure 3 1 is an optical microscope image of the composite yarn prepared under different gear transmission ratios of the present invention; in the image, (i) the gear transmission ratio is 0.3, (ii) the gear transmission ratio is 0.35, (iii) the gear transmission ratio is 0.4, (iv) the gear transmission ratio is 0.45, and (v) the gear transmission ratio is 0.5;

[0031] Figure 4 Schematic diagram of the flame retardant and smoke suppression performance test results of the composite yarn of the present invention; in the figure, (a) heat release rate curve, (b) total heat release curve;

[0032] Figure 5 is a total smoke release curve of the fabric of Example 1 of the present invention;

[0033] Figure 6 is the change in electrical output performance of the fabric of Example 1 of the present invention before and after combustion;

[0034] Figure 7 is the electrical output performance of the fabric of Example 1 of the present invention at different frequencies; in the figure, (a) V OC ; (b) I SC ; (c) Q SC ;

[0035] Figure 8 It is a schematic diagram of the variation of fabric current and power density with load resistance in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the invention of the present invention based on the disclosed content, and they should also fall within the scope of the present invention.

[0037] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels.

[0038] Example 1

[0039] A composite yarn has a skin-core structure, wherein the inner core is a silver-plated nylon filament and the outer friction layer is a PTFE filament;

[0040] The fineness of silver-plated nylon filament is 20D;

[0041] The fineness of the PTFE filament is 500D.

[0042] The composite yarn is continuously prepared using a XD05-8D-4T high-speed braiding machine (the high-speed braiding schematic diagram is shown in FIG. Figure 1 The method comprises the following steps: firstly, the PTFE filaments are pre-wound on a matching yarn tube, and the silver-plated nylon filaments are wound on a special bobbin in the middle of a high-speed braiding machine, and the filaments are fed axially from the bottom of the track disk, and a certain degree of tension is provided thereto, and the gear transmission ratio is set to 0.3 to start braiding; during the braiding process, the PTFE filaments are evenly divided into two groups, one group rotates clockwise and the other group rotates counterclockwise, and the PTFE filaments are woven into a dense outer friction layer on the outside of the silver-plated nylon filaments, thereby obtaining a composite yarn with a skin-core structure, and the SEM image of the composite yarn measured by a scanning electron microscope is as shown in FIG. Figure 2 shown.

[0043] This embodiment also provides a flame-retardant friction nano-electricity generating fabric with a perfluorinated friction outer layer, which is formed by weaving the above-mentioned composite yarn.

[0044] Example 2

[0045] A composite yarn has a skin-core structure, wherein the inner core is a silver-plated nylon filament and the outer friction layer is a PTFE filament;

[0046] The fineness of silver-plated nylon filament is 40D;

[0047] The fineness of the PTFE filament is 400D.

[0048] The preparation method of the above-mentioned composite yarn includes: firstly pre-winding the PTFE filaments on a matching yarn tube, and winding the silver-plated nylon filaments on a special spool in the middle of a high-speed braiding machine, feeding them axially from the bottom of the track disk, and providing them with a certain degree of tension, setting the gear transmission ratio to 0.35 to start weaving; during the weaving process, the PTFE filaments are evenly divided into two groups, one group rotates clockwise and the other group rotates counterclockwise, and the PTFE filaments are woven into a dense outer friction layer on the outside of the silver-plated nylon filaments, thereby obtaining a composite yarn with a skin-core structure.

[0049] This embodiment also provides a flame-retardant friction nano-electricity generating fabric with a perfluorinated friction outer layer, which is formed by weaving the above-mentioned composite yarn.

[0050] Example 3

[0051] A composite yarn has a skin-core structure, wherein the inner core is silver-plated nylon filament and the outer friction layer is PTFE filament;

[0052] The fineness of silver-plated nylon filament is 70D;

[0053] The fineness of the PTFE filament is 600D.

[0054] The preparation method of the above-mentioned composite yarn includes: firstly pre-winding the PTFE filaments on a matching yarn tube, and winding the silver-plated nylon filaments on a special spool in the middle of a high-speed braiding machine, feeding them axially from the bottom of the track disk, and providing them with a certain degree of tension, setting the gear transmission ratio to 0.35 to start weaving; during the weaving process, the PTFE filaments are evenly divided into two groups, one group rotates clockwise and the other group rotates counterclockwise, and the PTFE filaments are woven into a dense outer friction layer on the outside of the silver-plated nylon filaments, thereby obtaining a composite yarn with a skin-core structure.

[0055] This embodiment also provides a flame-retardant friction nano-electricity generating fabric with a perfluorinated friction outer layer, which is woven from the above composite yarn. The air permeability and moisture permeability of the fabric are tested according to the reference standard GB / T5453-1997. The results show that the air permeability of the fabric is 2980.1 mm / s and the water vapor permeability is 237.14 g / (m 2 h), good moisture permeability and breathability, good wearing comfort.

[0056] Comparative Example 1

[0057] The difference from Example 1 is that the fineness of the PTFE filament is 200D.

[0058] Comparative Example 2

[0059] The difference from Example 1 is that the fineness of the PTFE filament is 700D.

[0060] Comparative Example 3

[0061] The difference from Example 1 is that the gear transmission ratio is set to 0.4 during the preparation of the composite yarn.

[0062] Comparative Example 4

[0063] The difference from Example 1 is that the gear transmission ratio is set to 0.45 during the preparation of the composite yarn.

[0064] Comparative Example 5

[0065] The difference from Example 1 is that the gear transmission ratio is set to 0.5 during the preparation of the composite yarn.

[0066] Experimental Example 1

[0067] Structural characterization

[0068] The composite yarns in Examples 1, 2 and Comparative Examples 3-5 were observed using an optical microscope. The results are as follows: Figure 3 As shown in the figure, during the preparation of the composite yarn, the gear ratio is set to 0.3-0.35, so that the PTFE filaments can be tightly wrapped around the outside of the silver-plated nylon filaments, and the structure is tight.

[0069] Experimental Example 2

[0070] Flame retardant properties

[0071] (1) Referring to the method in GB / T5455-1997 standard, the limiting oxygen index (LOI) and vertical burning performance of the fabrics in Examples 1-3 and Comparative Examples 1 and 2 were tested. The results are shown in Table 1 below.

[0072] Table 1. LOI and vertical burning performance of fabrics

[0073] Group LOI(%) Afterburning time(s) Smoldering time(s) Damage length(mm) Whether it is molten drop Example 1 ＞70 0 0 11 no Example 2 ＞70 0 0 11.5 no Example 3 ＞70 0 0 11.8 no Comparative Example 1 ＞70 0 0 13 no Comparative Example 2 ＞70 0 0 8 no

[0074] The results show that the composite yarn prepared by the present invention with silver-plated nylon yarn as the conductive inner core and PTFE filament as the outer friction layer has an LOI value of ≥70%, an afterflame time and a smoldering time of 0s, no droplets occur during the combustion process, and has excellent flame retardant properties.

[0075] (2) The flame retardant and smoke suppression properties of the fabrics in Example 1 and Comparative Example 4 were tested by cone calorimeter. The results are as follows: Figure 4-6 shown.

[0076] The results show that the total heat release of the composite yarn of Example 1 of the present invention is 0.417 MJ / m 2 , almost no heat release rate peak is shown, and the total smoke release is 0.03m 2, almost no smoke release rate peak is shown, and the smoke suppression is high. In addition, the residual sample of FR-T-TENG after self-extinguishing still shows good electrical output performance, ensuring its long endurance in fire.

[0077] Experimental Example 3

[0078] The composite yarns of Example 1 and Comparative Examples 1-5 were woven into a fabric with a plain weave structure of 30 mm × 30 mm in size, and grounded with a Keithley electrometer. A linear motor was used to apply periodic contact and separation motion (fixed force of 60 N, frequency of 2 Hz), and the open circuit voltage (V OC ), short circuit current (I SC ) and short-circuit charge (Q SC ) to collect real-time data and measure its electrical output performance. The results are as follows Figure 7 , 8 And as shown in Table 2.

[0079] Table 2. Electrical output performance (pressure 60N, frequency 2Hz)

[0080]

[0081]

[0082] Figure 7 is the electrical output performance of the fabric at different frequencies, Figure 8 is the variation of the fabric current and power density with load resistance. Figure 7 , 8 As can be seen from the results in Table 2, the V OC =41V, I SC =0.5μA, Q SC =14nC, when the load resistance is 250MΩ, the fabric exhibits a maximum power density of 40.62mW·m -2 , and the electrical output performance is excellent. This may be because the fluorine group has the strongest electron-accepting ability, so PTFE has a high triboelectric negative property, which is conducive to obtaining a higher charge density under external pressure, which makes the fabric easy to generate tribostatic electricity under pressure. In addition, the outer friction layer of the fabric constructed by high-speed weaving is tightly coated on the outside of the conductive inner core, reducing charge leakage, thereby ensuring the excellent electrical output performance of the resulting fabric.

[0083] Experimental Example 4

[0084] Mechanical properties

[0085] With reference to the method in standard GB / T3923.1-2013, the tensile strength of the fabrics of Example 1 and Comparative Examples 1-5 was tested, and the results are shown in Table 3 below.

[0086] Table 3. Tensile strength

[0087]

[0088] The results show that the composite yarn prepared by using the silver-plated nylon yarn as the conductive inner core and the PTFE filament as the outer friction layer has high tensile strength and excellent mechanical properties.

[0089] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A composite yarn, characterized in that: It comprises a silver-plated nylon filament inner core and an outer friction layer; wherein the outer friction layer is PTFE filament or PTFE coating.

2. The composite yarn according to claim 1, characterized in that The fineness of the silver-plated nylon filament is 20-200D.

3. The composite yarn according to claim 1, characterized in that The fineness of the PTFE filament is 300-600D.

4. The composite yarn according to claim 3, characterized in that The fineness of the PTFE filament is 400-500D.

5. The composite yarn according to claim 1, characterized in that The PTFE coating contains PTFE and a solvent.

6. The composite yarn according to claim 1, characterized in that The PTFE coating further comprises an auxiliary agent, and the auxiliary agent is selected from at least one of a conductive nano filler, a dispersant, a surfactant, and a silane coupling agent.

7. The method for preparing the composite yarn according to any one of claims 1 to 6, characterized in that: When the outer friction layer is PTFE filaments, the method comprises the following steps: First, the PTFE filaments are pre-wound on the matching yarn tubes, and the silver-plated nylon filaments are wound on the special bobbin in the middle of the high-speed braiding machine, and fed axially from the bottom of the track disk, and the gear transmission ratio is set to start braiding; during the braiding process, the PTFE filaments are evenly divided into two groups, one group rotates clockwise and the other group rotates counterclockwise, so that the PTFE filaments are woven into a dense outer friction layer on the outside of the silver-plated nylon filaments, thereby obtaining a composite yarn with a skin-core structure; When the outer friction layer is a PTFE coating, the method comprises the following steps: The additive is dispersed in the PTFE aqueous solution to form a composite dispersion, and then the silver-plated nylon filament is immersed in the composite dispersion to obtain a composite yarn with the PTFE coating as the outer friction layer.

8. The method according to claim 7, characterized in that The gear transmission ratio is 0.3-0.

5.

9. The method according to claim 8, characterized in that The gear transmission ratio is 0.3-0.

35.

10. A flame-retardant friction nano-electricity generating fabric with a perfluorinated friction outer layer, characterized in that: The composite yarn is made by weaving the composite yarn described in any one of claims 1 to 6 or the composite yarn prepared by the method described in any one of claims 7 to 9.

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