A flexible conductive yarn and its preparation method and application

Abstract

The application discloses a kind of flexible conductive yarn and its preparation method and application;The method comprises the following steps: S1, polyamide film is stretched;S2, the film after stretching is first soaked in pyrrole solution;Again, it is soaked in mixed solution and carries out polymerization reaction, again twist, dry and obtain flexible conductive yarn;The concentration of the pyrrole solution is 1wt.%~2wt.%;The mixed solution includes sodium anthraquinone-2-sulfonate and ferric chloride.The polyamide film of the stretched filament is first soaked in pyrrole solution, and polyamide film containing pyrrole can be obtained, then pyrrole is polymerized into polypyrrole in the solution containing sodium anthraquinone-2-sulfonate (AQS) and ferric chloride, finally, the twisted film is twisted, so that the flexible conductive yarn with excellent mechanical properties, conductive stability, conductive performance and water resistance characteristics is prepared.

Description

Technical Field

[0001] This invention relates to the field of conductive yarn preparation technology, and in particular to a flexible conductive yarn, its preparation method, and its application. Background Technology

[0002] With the rapid development of technology, smart textiles and wearable technology have gradually become the focus of attention. In this field, conductive yarn, as its core basic material, plays a crucial role. Currently, the methods commonly used to prepare conductive fibers or yarns include coating technology, conductive material blending and chemical fiber spinning, and electrospinning technology. These technologies can significantly enhance the functionality of yarns and are widely used in the field of conductive yarns for smart textiles. However, the coating thickness is not easy to control, it is prone to peeling off, and the yarn feels stiff; conductive nanomaterial blending and spinning methods can easily lead to uneven material distribution, insufficient strength, and relatively brittle yarns; electrospinning technology makes it difficult to guarantee the elasticity, washability, and conductivity stability of conductive fibers, and it is not easy to mass-produce.

[0003] Therefore, it is of great significance to prepare a conductive yarn with good elasticity, high conductivity, good conductivity stability, and excellent water resistance. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes a method for preparing a flexible conductive yarn, wherein the flexible conductive yarn prepared by the method has excellent mechanical properties, electrical conductivity, and water resistance.

[0005] A second aspect of the present invention also provides a flexible conductive yarn.

[0006] A third aspect of the present invention also provides an application of flexible conductive yarn.

[0007] According to a first aspect of the present invention, a method for preparing a flexible conductive yarn is provided, comprising the following steps: S1. Stretch the polyamide film; S2. The stretched film is first soaked in a pyrrole solution; then it is soaked in a mixture to carry out a polymerization reaction, and then twisted and dried to obtain a flexible conductive yarn. The concentration of the pyrrole solution is 1 wt.% to 2 wt.%; the mixture includes sodium anthraquinone-2-sulfonate and ferric salt.

[0008] According to a preferred embodiment of the present invention, the concentration of the pyrrole solution is 1.21 wt.% to 1.68 wt.%.

[0009] According to a preferred embodiment of the present invention, the mass concentration of sodium anthraquinone-2-sulfonate in the mixture is 0.93 wt.% to 1.48 wt.%.

[0010] According to a preferred embodiment of the present invention, the mass concentration of the trivalent iron salt in the mixture is 1.62 wt.% to 2.43 wt.%.

[0011] According to a preferred embodiment of the present invention, the trivalent ferric salt is selected from at least one of ferric chloride, ferric bromide, and ferric iodide.

[0012] According to a preferred embodiment of the present invention, the temperature of the polymerization reaction is 0~5°C.

[0013] According to a preferred embodiment of the present invention, the polymerization reaction takes 0.5 to 5 hours.

[0014] According to a preferred embodiment of the present invention, the polymerization reaction takes 0.5 to 1 hour.

[0015] According to a preferred embodiment of the present invention, before step S2, the stretched film is first soaked in water.

[0016] According to a preferred embodiment of the present invention, the polyamide film is obtained by interfacial polymerization.

[0017] According to a preferred embodiment of the present invention, the polyamide film is prepared by the following method: A hexamethylenediamine solution and an alkaline solution were mixed to obtain an aqueous solution; the aqueous solution and an adipic acid chloride oil solution were mixed to carry out an interfacial polymerization reaction to obtain a polyamide film.

[0018] According to a preferred embodiment of the present invention, the mass concentration of the hexamethylenediamine solution in the aqueous phase solution is 3 wt.% to 5 wt.%.

[0019] According to a preferred embodiment of the present invention, the mass concentration of the adipic acid chloride oil phase solution is 1.5 wt.% to 5 wt.%.

[0020] The method for preparing flexible conductive yarn according to embodiments of the present invention has at least the following beneficial effects: This invention first soaks a stretched polyamide film in a pyrrole solution to obtain a polyamide film containing pyrrole. Then, the pyrrole is polymerized into polypyrrole in a solution containing sodium anthraquinone-2-sulfonate (AQS) and ferric chloride. Finally, the drawn film is twisted to prepare a flexible conductive yarn with excellent mechanical properties, electrical conductivity, electrical stability and water resistance.

[0021] Furthermore, this invention fully utilizes the ridge-valley effect on the surface of the polyamide film. By stretching the film, pyrrole is filled into the ridge-valley. Through van der Waals forces (originating from the instantaneous dipole and induced dipole between molecules / atoms) and hydrogen bonding, as well as some electrostatic interactions, the adsorption of pyrrole on the surface of the polyamide film is made more robust, with no slippage. The resistance does not easily increase with washing and stretching.

[0022] Furthermore, because pyrrole is uniformly distributed within the film, and the final twisting process prevents the conductivity from significantly decreasing with yarn elongation, the conductivity stability of the flexible conductive yarn of this invention is greatly improved. This significantly overcomes the shortcomings of preparing conductive yarn by adding inorganic nanomaterials or coatings.

[0023] According to a second aspect of the present invention, a flexible conductive yarn is provided, which is prepared by the preparation method described in the first aspect of the present invention.

[0024] A third aspect of the present invention provides the application of the conductive yarn described in the second aspect of the present invention in the preparation of smart textiles.

[0025] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the preparation steps of the flexible conductive yarn in Embodiment 1 of the present invention; Figure 2 These are SEM images of the stretched film and the film after soaking in pyrrole solution according to Example 9 of the present invention. Detailed Implementation

[0027] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0028] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0029] In some embodiments of the present invention, a method for preparing a flexible conductive yarn is provided, comprising the following steps: S1. Stretch the polyamide film; S2. The stretched film is first soaked in a pyrrole solution; then it is soaked in a mixture to carry out a polymerization reaction, and then twisted and dried to obtain a flexible conductive yarn. The concentration of the pyrrole solution is 1 wt.% to 2 wt.%; the mixture includes sodium anthraquinone-2-sulfonate and ferric salt.

[0030] The relevant technology typically polymerizes polypyrrole on the surface of the yarn to form polypyrrole. This method can lead to insufficient in-situ reaction in the yarn, and the core cannot be guaranteed to participate in the reaction. Furthermore, the resistance of the yarn tends to increase due to washing and stretching (fiber slippage and misalignment), resulting in poor conductivity stability.

[0031] Understandably, the present invention first soaks the stretched polyamide film in a pyrrole solution to obtain a polyamide film containing pyrrole, then polymerizes the pyrrole into polypyrrole in a solution containing sodium anthraquinone-2-sulfonate (AQS) and ferric chloride, and finally twists the drawn film to prepare a flexible conductive yarn with excellent mechanical properties, electrical stability, electrical conductivity and water resistance.

[0032] Furthermore, this invention fully utilizes the ridge-valley effect on the surface of the polyamide film. By stretching the film, pyrrole is filled into the ridge-valley. Through van der Waals forces (originating from the instantaneous dipole and induced dipole between molecules / atoms) and hydrogen bonding, as well as some electrostatic interactions, the adsorption of pyrrole on the surface of the polyamide film is made more robust, with no slippage. The resistance does not easily increase with washing and stretching.

[0033] Furthermore, because pyrrole is uniformly distributed within the film, and the final twisting process prevents the conductivity from significantly decreasing with yarn elongation, the conductivity stability of the flexible conductive yarn of this invention is greatly improved. This significantly overcomes the shortcomings of preparing conductive yarn by adding inorganic nanomaterials or coatings.

[0034] In some embodiments of the present invention, the concentration of the pyrrole solution is 1.21 wt.% to 1.68 wt.%. For example, it includes 1.21 wt.%, 1.25 wt.%, 1.28 wt.%, 1.30 wt.%, 1.33 wt.%, 1.36 wt.%, 1.38 wt.%, 1.40 wt.%, 1.41 wt.%, 1.44 wt.%, 1.46 wt.%, 1.48 wt.%, 1.50 wt.%, 1.52 wt.%, 1.54 wt.%, 1.56 wt.%, 1.58 wt.%, 1.60 wt.%, 1.62 wt.%, 1.64 wt.%, 1.66 wt.%, 1.68 wt.%, or any sub-range consisting of any two of the above values.

[0035] In some embodiments of the present invention, the film is first immersed in the pyrrole solution for 10 to 40 minutes. For example, this includes 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, or any sub-range consisting of two of the above values.

[0036] In some embodiments of the present invention, the mass concentration of sodium anthraquinone-2-sulfonate in the mixture is 0.93 wt.% to 1.48 wt.%. For example, it includes 0.93 wt.%, 0.95 wt.%, 0.98 wt.%, 0.1 wt.%, 0.12 wt.%, 0.15 wt.%, 0.2 wt.%, 0.25 wt.%, 0.3 wt.%, 0.35 wt.%, 0.40 wt.%, 0.45 wt.%, 0.48 wt.%, or any subrange consisting of any two of the above values.

[0037] In some embodiments of the present invention, the mass concentration of the trivalent iron salt in the mixture is 1.62 wt.% to 2.43 wt.%. For example, it includes 1.62 wt.%, 1.68 wt.%, 1.7 wt.%, 1.75 wt.%, 1.8 wt.%, 1.9 wt.%, 2.0 wt.%, 2.1 wt.%, 2.2 wt.%, 2.3 wt.%, 2.4 wt.%, 2.43 wt.%, or any sub-range consisting of any two of the above values.

[0038] In some embodiments of the present invention, the ferric salt is selected from at least one of ferric chloride, ferric bromide, and ferric iodide.

[0039] In some embodiments of the present invention, the reaction temperature of the polymerization reaction is 0~5°C. For example, it includes 0°C, 1°C, 1.5°C, 2°C, 3°C, 4°C, 5°C, or any two of the above values.

[0040] In some embodiments of the present invention, the polymerization reaction time is 0.5 to 5 hours. For example, it includes 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, or any sub-range consisting of any two of the above values.

[0041] In some embodiments of the present invention, the stretched film is first immersed in water before step S2. This removes organic solvents from the stretched film and improves the crosslinking degree of the polyamide.

[0042] In some embodiments of the present invention, the temperature of the water is 30°C to 50°C.

[0043] In some embodiments of the present invention, the polyamide film is obtained by interfacial polymerization.

[0044] In some embodiments of the present invention, the polyamide film is prepared by the following method: A hexamethylenediamine solution and an alkaline solution were mixed to obtain an aqueous solution; the aqueous solution and an adipic acid chloride oil solution were mixed to carry out an interfacial polymerization reaction to obtain a polyamide film.

[0045] In some embodiments of the present invention, the mass concentration of the hexamethylenediamine solution in the aqueous phase solution is 3 wt.% to 5 wt.%. For example, it includes 3 wt.%, 3.5 wt.%, 4 wt.%, 4.5 wt.%, 5 wt.%, 5.5 wt.%, 6 wt.%, or any sub-range consisting of any two of the above values.

[0046] In some embodiments of the present invention, the mass concentration of the adipic acid chloride oil phase solution is 1.5 wt.% to 5 wt.%. For example, it includes 1.5 wt.%, 2 wt.%, 2.5 wt.%, 3 wt.%, 3.5 wt.%, 4 wt.%, 4.5 wt.%, 5 wt.%, or any sub-range consisting of any two of the above values.

[0047] In some embodiments of the present invention, the twist coefficient is 100 to 250. For example, it includes 100, 114, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250 or any two of the above values.

[0048] The twist coefficient is calculated using the following formula: α=t*T^(1 / 2); where α—twist coefficient; t—twist degree, twist / 10cm; T—yarn linear density, tex.

[0049] According to a second aspect of the present invention, a flexible conductive yarn is provided, which is prepared by the preparation method described in the first aspect of the present invention.

[0050] A third aspect of the present invention provides the application of the conductive yarn described in the second aspect of the present invention in the preparation of smart textiles.

[0051] Example 1 This example provides a flexible conductive yarn, the preparation schematic of which is shown below. Figure 1 As shown, the specific steps are as follows: Prepare a homogeneous aqueous solution: an aqueous solution with a mass concentration of 4.0 wt% hexamethylenediamine and a mass concentration of 3.0 wt% sodium hydroxide; prepare an oil phase monomer solution: an oil phase solution of n-hexane with a mass concentration of 3.2 wt% adipic acid chloride.

[0052] S1. At room temperature, the oil phase solution is slowly poured into a container containing the aqueous phase solution to carry out the interfacial polymerization reaction for a certain period of time, 10 seconds, at a temperature of 25°C. During this time, a thin film can be observed to form at the interface. Subsequently, the polymerized film is stretched at a uniform speed from its center into a continuous long film using a roller stretching machine, and then immersed in water at a certain temperature of 50°C for 30 minutes.

[0053] S2. Then, the dried, continuous long film is taken out and immersed in a pyrrole solution with a mass concentration of 1.21 wt% for 30 min. After that, it is placed in a mixed solution of anthraquinone-2-sulfonate sodium with a mass concentration of 1.48 wt% and ferric chloride with a mass concentration of 2.43 wt% in an ice bath for 2 h to allow the pyrrole to polymerize into polypyrrole. Then, the filament containing the polypyrrole film is taken out, twisted, and dried to make it a conductive yarn with a certain strength and elasticity. The drying time is 10 min, the temperature is 80℃, and the twist coefficient is 114.

[0054] Example 2 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 1, except that the mass concentration of pyrrole is 1.41 wt.%.

[0055] Example 3 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 1, except that the mass concentration of pyrrole is 1.54 wt.%.

[0056] Example 4 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 1, except that the mass concentration of pyrrole is 1.68 wt.%.

[0057] Example 5 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 1, except that the mass concentration of pyrrole is 1.81 wt.%.

[0058] Example 6 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 1, except that the mass concentration of pyrrole is 1.0 wt.%.

[0059] Example 7 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 1, except that the mass concentration of pyrrole is 2.0 wt.%.

[0060] Example 8 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 2, except that the ice bath time is 0.5h.

[0061] Example 9 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 2, except that the ice bath time is 1 hour.

[0062] The continuous long film from step S1 and the film after soaking in pyrrole solution were subjected to SEM testing, and the results are as follows: Figure 2 As shown, where Figure 2 In the image, 'a' represents the SEM image of the filament film. Figure 2 In the image, b represents the SEM image after soaking in the pyrrole solution. SEM characterization revealed that the surface of the polyamide film without pyrrole exhibited a significant ridge-valley effect. In contrast, the ridges and valleys on the surface of the polyamide film with pyrrole were filled with pyrrole, resulting in a more stable bond between pyrrole and the polyamide film.

[0063] Example 10 This example provides a flexible conductive yarn, the raw material dosage and preparation method of which are the same as in Example 2, except that the ice bath time is 1.5h.

[0064] Comparative Example 1 This example provides a flexible conductive yarn, the preparation method of which is as follows: Prepare a homogeneous aqueous solution: an aqueous solution with a mass concentration of 4.0 wt% hexamethylenediamine and a mass concentration of 3.0 wt% sodium hydroxide; prepare an oil phase monomer solution: an oil phase solution of n-hexane with a mass concentration of 3.2 wt% adipic acid chloride.

[0065] S1. At room temperature, the oil phase solution is slowly poured into a container containing the aqueous phase solution to allow for interfacial polymerization for a certain period of time (10 seconds) at 25°C. During this time, a thin film can be observed forming at the interface. Subsequently, the polymerized film is stretched using a roller machine at a uniform speed from its center into a filament. The stretched filament is then immersed in water at 50°C for 30 minutes. Afterward, the dried film filament is removed and twisted to obtain yarn; the twist coefficient is 114.

[0066] S2. The prepared yarn is immersed in a pyrrole solution with a mass concentration of 1.21 wt% for 30 min, and then placed in a mixed solution of anthraquinone-2-sulfonate sodium with a mass concentration of 1.48 wt% and ferric chloride with a mass concentration of 2.43 wt% in an ice bath for 2 h to allow the pyrrole to polymerize into polypyrrole. Then it is dried at a temperature of 80℃ for 10 min to obtain the conductive yarn.

[0067] Performance testing The yarn's resistance was tested using a multimeter, its diameter was measured using a handheld digital thickness gauge, its breaking strength and elongation at break were tested using a tensile testing machine, its weight was measured using an electronic balance, its length was measured using vernier calipers, and its surface morphology was characterized using scanning electron microscopy (SEM). The specific results are shown in Table 1.

[0068] The formula for calculating electrical conductivity is: σ=L / RS Where σ is the conductivity, R represents the resistance, S is the cross-sectional area, and L is the length.

[0069] The formula for calculating linear density is: Tt=1000 GK / L Where Tt is the linear density, Gk is the yarn weight, and L is the yarn length.

[0070] Table 1

[0071] As shown in Table 1, the electrical conductivity of the yarn gradually increases with the increase of pyrrole concentration, but its mechanical properties gradually decrease. When the concentration exceeds that of Example 7, the yarn will be difficult to twist into yarn due to its poor mechanical properties.

[0072] Furthermore, the effects of different ice bath times on electrical conductivity and mechanical properties were investigated, and the specific results are shown in Table 2: Table 2

[0073] As can be seen from the data in Table 2, the longer the ice bath time, the stronger the electrical conductivity, but the worse the mechanical properties. When the ice bath time exceeds that of Example 2, it will be difficult to twist into yarn due to the poor mechanical properties.

[0074] Furthermore, the effects of Examples 8, 9, and 10 on the stability of conductivity were investigated, and the specific results are shown in Table 3.

[0075] Table 3

[0076] As shown in Table 3, the longer the ice bath time, the worse the tensile properties. When the time is within 0.5 to 1.5 hours, the tensile properties are better.

[0077] Furthermore, the wash resistance of the embodiments and comparative examples of the present invention was investigated: 10cm segments of yarn were placed in a 500ml beaker, deionized water was added, and the beaker was placed in a magnetic stirrer at 100r / min for 5 minutes each time. The yarn was then removed and dried at 45℃. Each segment was washed 10 times. The rate of change in resistance was calculated using the following formula:

[0078] in, This is the initial resistance (the resistance value before stretching or deformation). This refers to the real-time resistance (resistance value during stretching or deformation).

[0079] Table 4

[0080] As can be seen from the data in Table 4, the resistance change rate of the flexible conductive yarns in Examples 1 to 10 of the present invention is relatively low, indicating that the flexible conductive yarns of the present invention have better water resistance.

[0081] The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing a flexible conductive yarn, characterized in that, Includes the following steps: S1. Stretch the polyamide film; S2. The stretched film is first soaked in a pyrrole solution; then it is soaked in a mixture to carry out a polymerization reaction, and then twisted and dried to obtain a flexible conductive yarn. The concentration of the pyrrole solution is 1 wt.% to 2 wt.%; the mixture includes sodium anthraquinone-2-sulfonate and ferric salt.

2. The preparation method according to claim 1, characterized in that, The concentration of the pyrrole solution is 1.21 wt.% to 1.68 wt.%.

3. The preparation method according to claim 1, characterized in that, In the mixture, the mass concentration of sodium anthraquinone-2-sulfonate is 0.93 wt.% to 1.48 wt.%.

4. The preparation method according to claim 1, characterized in that, In the mixture, the mass concentration of the trivalent iron salt is 1.62 wt.% to 2.43 wt.%. And / or, the ferric salt is selected from at least one of ferric chloride, ferric bromide, and ferric iodide.

5. The preparation method according to claim 1, characterized in that, The polymerization reaction is carried out at a temperature of 0~5℃.

6. The preparation method according to claim 1, characterized in that, The polymerization reaction takes 0.5 to 5 hours.

7. The preparation method according to claim 1 or 6, characterized in that, The polyamide film is prepared by the following method: A hexamethylenediamine solution and an alkaline solution were mixed to obtain an aqueous solution; the aqueous solution and an adipic acid chloride oil solution were mixed to carry out an interfacial polymerization reaction to obtain a polyamide film.

8. The preparation method according to claim 1, characterized in that, The mass concentration of hexamethylenediamine solution in the aqueous phase solution is 3 wt.% to 5 wt.%. And / or, the mass concentration of the adipic acid chloride oil phase solution is 1.5 wt.% to 5 wt.%.

9. A flexible conductive yarn, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the conductive yarn as described in claim 9 in the preparation of smart textiles.

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