Stretchable conductive fiber with stable resistance and continuous preparation method thereof

Abstract

The invention discloses a stretchable conductive fiber with stable resistance and a continuous preparation method thereof, and the method comprises the following steps: S1, taking an elastic fiber as a base line, paying off through a feeding roller, wetting, coating a carbon nanotube, carrying out solvent bath, drying, and taking up through a collecting roller; the linear speed of the collecting roller is greater than that of the feeding roller; s2, paying off the fiber obtained in the previous step through a feeding roller, wetting, coating the carbon nano tube, performing solvent bath, drying, and taking up through a collecting roller; the linear speeds of the feeding roller and the collecting roller are the same as that in the step S1; and S3, repeating the step S2 to coat multiple layers of carbon nanotubes to obtain the stretchable conductive carbon fiber with stable resistance. According to the method, the elastic fiber serves as a base line, the elastic fiber is stretched to the preset multiple through the speed difference between the feeding roller and the collecting roller, the stretchable conductive fiber with the stable resistance is obtained through multiple times of wetting and coating of the carbon nano tube, the preparation method is simple, the cost is low, and continuous production can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive fibers, and in particular to a stretchable conductive fiber with stable resistance and a continuous preparation method thereof. Background Art

[0002] Stretchable conductive fibers are a type of fiber that has certain mechanical and electrical properties. They can effectively solve the problem that deformation and conductive stability cannot coexist in traditional rigid wires. They have broad application prospects in smart textiles, wearable electronic devices, human motion detection and other fields.

[0003] At present, there are three main methods for preparing stretchable conductive fibers: The first method is to disperse the conductive material in a polymer elastomer solution and prepare elastic conductive fibers by wet spinning. For example, in the literature (Appl. Mater. Today, 2018, 11, 255), poly(3,4-ethylenedioxythiophene), polystyrene sulfonate and polyurethane solution are mixed to obtain a spinning solution, and then an elastic conductive yarn is prepared by a wet spinning process. This method can achieve the continuous preparation of stretchable conductive fibers, but due to the limited addition of conductive components, the conductive properties of the prepared fibers need to be improved. The second method is to coat the outer layer of the existing elastic fiber with a conductive material, thereby giving the elastic fiber a certain conductivity. For example, patent CN114108152B discloses a method for preparing a multi-layered composite yarn with both strain sensing and tensile resistance stability, using spandex filaments as core yarns, adding a conductive wrinkle layer (the conductive material is carbon nanotubes or liquid metal) on this basis, and then using electrostatic spinning for surface coating, and then coating carbon-based nanomaterials and metal nanomaterials, and finally coating a layer of electrostatically spun fiber mesh to prepare a complete yarn. Although the multi-level structure disclosed in this patent can well avoid the problem of nanomaterial shedding, the preparation method is complicated, the materials used are more, and the cost is high. The third method is to first prepare conductive fibers, and then wrap them on the surface of elastic fiber filaments to prepare elastic conductive yarns. For example, patent CN110129942B discloses elastic conductive yarns and their preparation methods, first using ring spinning to prepare conductive core-spun yarns, and then twisting and wrapping the elastic fiber filaments with the obtained conductive core-spun yarns to finally obtain elastic conductive yarns. This preparation method is easy to achieve large-scale production, but the preparation process is complicated, and there is a problem of unstable resistance under large deformation.

[0004] Therefore, it is of great significance to develop a stretchable conductive fiber with stable resistance, simple preparation method, continuous operation and low cost. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a stretchable conductive fiber with stable resistance and a continuous preparation method thereof. With elastic fiber as a baseline, the elastic fiber is stretched to a preset multiple through the speed difference between a feeding roller and a collecting roller, and the stretchable conductive fiber with stable resistance is obtained by multiple wetting and coating of carbon nanotubes. The preparation method is simple, low-cost, and can realize continuous production.

[0006] In order to solve the above technical problems, the present invention provides a continuous preparation method of stretchable conductive fibers with stable resistance, comprising the following steps:

[0007] S1, taking the elastic fiber as the baseline, unwinding through a feeding roller, wetting, coating with carbon nanotubes, solvent bathing, and drying, and then winding through a collecting roller. After winding, the tension is released and the elastic fiber shrinks;

[0008] Wherein, the linear speeds of the feeding roller and the collecting roller are set according to the pre-stretching multiple, and the linear speed of the collecting roller is greater than the linear speed of the feeding roller;

[0009] S2, the fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up through a collecting roller, and after the taking-up is completed, the tension is released, and the elastic fiber shrinks;

[0010] Wherein, the linear speed of the feeding roller and the collecting roller is the same as that in step S1;

[0011] S3, repeat step S2 to coat multiple layers of carbon nanotubes to obtain the stretchable conductive carbon fiber with stable resistance.

[0012] The present invention uses elastic fiber as the baseline, and through the speed difference between the feeding roller and the collecting roller, the elastic fiber is stretched to a preset multiple, the stretching multiple of the fiber is maintained, and the carbon nanotubes are repeatedly wetted and coated. After the coating of multiple layers of carbon nanotubes is completed, the stretching force is released, the fiber shrinks, and the carbon nanotube layer folds with the shrinkage of the baseline, thereby obtaining a stretchable conductive fiber with stable resistance. When the fiber is used, when it is stretched again, the folded carbon nanotube layer produces spatial reconstruction with the stretching of the baseline, and the carbon nanotube layer has a strong bonding force with the baseline wetted with a polyurethane solution, and there is no risk of falling off, so the conductive performance of the fiber is stable. The diameter and resistance of the stretchable conductive fiber are adjusted by adjusting the thickness of the baseline and the number of coatings. The preparation method is simple, low-cost, and can achieve continuous production.

[0013] Furthermore, the pre-stretching multiple is 1.5-4 times.

[0014] Furthermore, in S1 and S2, the solution used for wetting is an aqueous polyurethane solution with a mass concentration of 5%-10%. After being wetted with the aqueous polyurethane solution, the carbon nanotubes are coated. The polyurethane plays a bonding role between the baseline and the carbon nanotube layer, thereby improving the bonding strength between the two and reducing the risk of carbon nanotubes falling off.

[0015] Furthermore, the elastic fiber is polyurethane fiber, and the fineness of the elastic fiber is 280-2280D.

[0016] Furthermore, in S1 and S2, the coating is specifically to contact the moistened elastic fiber with the carbon nanotubes to coat the surface of the elastic fiber with a layer of carbon nanotubes.

[0017] Furthermore, in S1 and S2, the carbon nanotubes are prepared by a floating catalyst chemical vapor deposition method.

[0018] Furthermore, in S1 and S2, the solvent used in the solvent bath is water, ethanol or acetone.

[0019] Furthermore, the number of repetitions is 0-4 times.

[0020] The second aspect of the present invention discloses a stretchable conductive fiber with stable resistance prepared by the preparation method described in the first aspect.

[0021] Furthermore, when the tensile deformation rate of the fiber is 50%-300%, the resistance change rate is less than 15%.

[0022] Beneficial effects of the present invention:

[0023] The present invention uses elastic fiber as the base line, and coats the carbon nanotube cylinder on the pre-stretched base line surface. After releasing the stretching force, a stretchable conductive fiber with stable resistance is obtained. The preparation method is simple, low-cost, can be carried out continuously, and is suitable for mass production.

[0024] The stretchable conductive fiber with stable resistance prepared by the method of the present invention has good bonding strength between the outer carbon nanotube layer and the inner elastic fiber baseline, has no risk of falling off, can achieve stable conductive performance within a certain deformation range, and has good flexibility.

[0025] The present invention can adjust the diameter and resistance of the fiber by adjusting the thickness of the base line and the number of coatings, thereby obtaining stretchable conductive fibers with different sizes and resistances. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a SEM image of the conductive fiber prepared in Example 1 of the present invention;

[0028] Figure 2 is a SEM image of the conductive fiber prepared in Example 2 of the present invention;

[0029] Figure 3 is a SEM image of the conductive fiber prepared in Example 3 of the present invention;

[0030] Figure 4 3 is a graph showing the resistance change of the conductive fiber prepared in Example 4 of the present invention under different tensile deformations. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment relates to a continuous preparation method of a stretchable conductive fiber with stable resistance, comprising the following steps:

[0034] (1) Preparation of carbon nanotube cylinders by floating catalyst chemical vapor deposition:

[0035] A mixture of a catalyst precursor, a growth promoter and a carbon source is fed through a peristaltic pump and carried into a reactor by a carrier gas for reaction to obtain a carbon nanotube cylindrical object, wherein the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol, the mass ratio of the three is 98.8:0.6:0.6, the reaction temperature is 1300°C, and the carrier gas is high-purity nitrogen;

[0036] (2) With polyurethane fiber as the baseline (fineness of 560D), the fiber is released through a feeding roller, wetted, coated with carbon nanotubes, solvent bathed, and dried, and then taken up by a collecting roller. After the taking up, the tension is released and the elastic fiber retracts; wherein the linear speeds of the feeding roller and the collecting roller are set to pre-stretch the polyurethane fiber to 3 times of its original length;

[0037] (3) The fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up by a collecting roller. After the taking-up is completed, the tension is released, and the elastic fiber shrinks; wherein the linear speed of the feeding roller and the collecting roller is the same as that in step (2);

[0038] (4) repeating step (3) three times to obtain the stretchable conductive carbon fiber with stable resistance;

[0039] Among them, in step (2) and step (3), the wetting is specifically carried out by dripping an aqueous polyurethane solution with a concentration of 5wt.% to wet the fiber; the wrapping of the carbon nanotubes is specifically carried out by contacting the wetted fiber with a carbon nanotube cylinder, that is, the fiber surface is coated with the carbon nanotube cylinder; the solvent of the solvent bath is ethanol; and the drying condition is drying at 80°C for 1 hour.

[0040] The scanning electron microscope image of the stretchable conductive fiber finally obtained in this embodiment is as follows: Figure 1 As shown, the fiber surface is evenly coated with carbon nanotubes, and the carbon nanotube layer is wrapped around the baseline surface in circles. This is because the carbon nanotubes are wrapped in the pre-stretched state. After the tensile force is released, the fiber shrinks and the carbon nanotube layer folds with the baseline shrinkage. Its line resistance is 47.5±2.5Ωcm -1 When stretched, the resistance change rate increases with the deformation rate. When the stretching deformation rate is 200%, the resistance change rate of the stretchable conductive fiber is less than 12%.

[0041] Example 2

[0042] This embodiment relates to a continuous preparation method of a stretchable conductive fiber with stable resistance, comprising the following steps:

[0043] (1) Preparation of carbon nanotube cylinders by floating catalyst chemical vapor deposition:

[0044] A mixture of a catalyst precursor, a growth promoter and a carbon source is fed through a peristaltic pump and carried into a reactor by a carrier gas for reaction to obtain a carbon nanotube cylindrical object, wherein the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol, the mass ratio of the three is 98.8:0.6:0.6, the reaction temperature is 1300°C, and the carrier gas is high-purity nitrogen;

[0045] (2) With polyurethane fiber as the baseline (fineness of 840D), the fiber is released through a feeding roller, wetted, coated with carbon nanotubes, solvent bathed, and dried, and then taken up by a collecting roller. After the taking up, the tension is released and the elastic fiber retracts; wherein the linear speeds of the feeding roller and the collecting roller are set to pre-stretch the polyurethane fiber to 4 times of its original length;

[0046] (3) The fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up by a collecting roller. After the taking-up is completed, the tension is released, and the elastic fiber shrinks; wherein the linear speed of the feeding roller and the collecting roller is the same as that in step (2);

[0047] (4) repeating step (3) once to obtain the stretchable conductive carbon fiber with stable resistance;

[0048] Among them, in step (2) and step (3), the wetting is specifically carried out by dripping an aqueous polyurethane solution with a concentration of 7.5wt.% to wet the fiber; the wrapping of the carbon nanotubes is specifically carried out by contacting the wetted fiber with a carbon nanotube cylinder, so that the fiber surface is coated with the carbon nanotube cylinder; the solvent of the solvent bath is ethanol; and the drying condition is drying at 80°C for 1 hour.

[0049] The scanning electron microscope image of the stretchable conductive fiber finally obtained in this embodiment is as follows: Figure 2 As shown, similar to the fiber obtained in Example 1, it can be seen that the fiber surface is evenly coated with a carbon nanotube layer. Its line resistance is 60.0±3.0Ωcm -1 During stretching deformation, as the deformation rate increases, the resistance change rate increases. When the stretching deformation rate is 300%, the resistance change rate of the stretchable conductive fiber is less than 13%.

[0050] Example 3

[0051] This embodiment relates to a continuous preparation method of a stretchable conductive fiber with stable resistance, comprising the following steps:

[0052] (1) Preparation of carbon nanotube cylinders by floating catalyst chemical vapor deposition:

[0053] A mixture of a catalyst precursor, a growth promoter and a carbon source is fed through a peristaltic pump and carried into a reactor by a carrier gas for reaction to obtain a carbon nanotube cylindrical object, wherein the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol, the mass ratio of the three is 98.8:0.6:0.6, the reaction temperature is 1300°C, and the carrier gas is high-purity nitrogen;

[0054] (2) With polyurethane fiber as the baseline (fineness of 1120D), the fiber is released through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, the fiber is taken up through a collecting roller. After the taking-up, the tension is released, and the elastic fiber retracts; wherein the linear speeds of the feeding roller and the collecting roller are set to pre-stretch the polyurethane fiber to 4 times of its original length;

[0055] (3) The fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up by a collecting roller. After the taking-up is completed, the tension is released, and the elastic fiber shrinks; wherein the linear speed of the feeding roller and the collecting roller is the same as that in step (2);

[0056] (4) repeating step (3) once to obtain the stretchable conductive carbon fiber with stable resistance;

[0057] Among them, in step (2) and step (3), the wetting is specifically carried out by dripping an aqueous polyurethane solution with a concentration of 7.5wt.% to wet the fiber; the wrapping of the carbon nanotubes is specifically carried out by contacting the wetted fiber with a carbon nanotube cylinder, so that the fiber surface is coated with the carbon nanotube cylinder; the solvent of the solvent bath is ethanol; and the drying condition is drying at 80°C for 1 hour.

[0058] The scanning electron microscope image of the stretchable conductive fiber finally obtained in this embodiment is as follows: Figure 3 As shown, similar to the fiber obtained in Example 1, it can be seen that the fiber surface is evenly coated with a carbon nanotube layer. Its line resistance is 98.0±3.5Ωcm -1 When stretched, the resistance change rate increases with the deformation rate. When the stretching deformation rate is 300%, the resistance change rate of the stretchable conductive fiber is less than 15%.

[0059] Example 4

[0060] This embodiment relates to a continuous preparation method of a stretchable conductive fiber with stable resistance, comprising the following steps:

[0061] (1) Preparation of carbon nanotube cylinders by floating catalyst chemical vapor deposition:

[0062] A mixture of a catalyst precursor, a growth promoter and a carbon source is fed through a peristaltic pump and carried into a reactor by a carrier gas for reaction to obtain a carbon nanotube cylindrical object, wherein the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol, the mass ratio of the three is 98.8:0.6:0.6, the reaction temperature is 1300°C, and the carrier gas is high-purity nitrogen;

[0063] (2) With polyurethane fiber as the baseline (fineness of 1120D), the fiber is released through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, the fiber is taken up through a collecting roller. After the taking-up, the tension is released, and the elastic fiber retracts; wherein the linear speeds of the feeding roller and the collecting roller are set to pre-stretch the polyurethane fiber to 4 times of its original length;

[0064] (3) The fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up by a collecting roller. After the taking-up is completed, the tension is released, and the elastic fiber shrinks; wherein the linear speed of the feeding roller and the collecting roller is the same as that in step (2);

[0065] (4) repeating step (3) three times to obtain the stretchable conductive carbon fiber with stable resistance;

[0066] Among them, in step (2) and step (3), the wetting is specifically carried out by dripping an aqueous polyurethane solution with a concentration of 7.5wt.% to wet the fiber; the wrapping of the carbon nanotubes is specifically carried out by contacting the wetted fiber with a carbon nanotube cylinder, so that the fiber surface is coated with the carbon nanotube cylinder; the solvent of the solvent bath is ethanol; and the drying condition is drying at 80°C for 1 hour.

[0067] The line resistance of the stretchable conductive fiber finally prepared in this embodiment is 86.0±2.5Ωcm -1 When stretched, the resistance change rate increases with the deformation rate. When the stretching deformation rate is 300%, the resistance change rate of the stretchable conductive fiber is less than 14%. Figure 4 .

[0068] Example 5

[0069] This embodiment relates to a continuous preparation method of a stretchable conductive fiber with stable resistance, comprising the following steps:

[0070] (1) Preparation of carbon nanotube cylinders by floating catalyst chemical vapor deposition:

[0071] A mixture of a catalyst precursor, a growth promoter and a carbon source is fed through a peristaltic pump and carried into a reactor by a carrier gas for reaction to obtain a carbon nanotube cylindrical object, wherein the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol, the mass ratio of the three is 98.8:0.6:0.6, the reaction temperature is 1300°C, and the carrier gas is high-purity nitrogen;

[0072] (2) With polyurethane fiber as the baseline (fineness of 2280D), the fiber is released through a feeding roller, wetted, coated with carbon nanotubes, solvent bathed, and dried, and then taken up by a collecting roller. After the taking up, the tension is released and the elastic fiber retracts; wherein the linear speeds of the feeding roller and the collecting roller are set to pre-stretch the polyurethane fiber to 3 times of its original length;

[0073] (3) The fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up by a collecting roller. After the taking-up is completed, the tension is released, and the elastic fiber shrinks; wherein the linear speed of the feeding roller and the collecting roller is the same as that in step (2);

[0074] (4) repeating step (3) three times to obtain the stretchable conductive carbon fiber with stable resistance;

[0075] Among them, in step (2) and step (3), the wetting is specifically carried out by dripping an aqueous polyurethane solution with a concentration of 10wt.% to wet the fiber; the wrapping of the carbon nanotubes is specifically carried out by contacting the wetted fiber with a carbon nanotube cylinder, so that the fiber surface is coated with the carbon nanotube cylinder; the solvent of the solvent bath is ethanol; and the drying condition is drying at 80°C for 1 hour.

[0076] The line resistance of the finally obtained stretchable conductive fiber in this embodiment is 115.0±1.5Ωcm -1 During stretching deformation, as the deformation rate increases, the resistance change rate increases. When the stretching deformation rate is 200%, the resistance change rate of the stretchable conductive fiber is less than 15%.

[0077] Example 6

[0078] This embodiment relates to a continuous preparation method of a stretchable conductive fiber with stable resistance, comprising the following steps:

[0079] (1) Preparation of carbon nanotube cylinders by floating catalyst chemical vapor deposition:

[0080] A mixture of a catalyst precursor, a growth promoter and a carbon source is fed through a peristaltic pump and carried into a reactor by a carrier gas for reaction to obtain a carbon nanotube cylindrical object, wherein the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol, the mass ratio of the three is 98.8:0.6:0.6, the reaction temperature is 1300°C, and the carrier gas is high-purity nitrogen;

[0081] (2) With polyurethane fiber as the baseline (fineness of 560D), the fiber is released through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, the fiber is taken up through a collecting roller. After the taking-up, the tension is released, and the elastic fiber retracts; wherein the linear speeds of the feeding roller and the collecting roller are set to pre-stretch the polyurethane fiber to twice its original length;

[0082] (3) The fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up by a collecting roller. After the taking-up is completed, the tension is released, and the elastic fiber shrinks; wherein the linear speed of the feeding roller and the collecting roller is the same as that in step (2);

[0083] (4) repeating step (3) once to obtain the stretchable conductive carbon fiber with stable resistance;

[0084] Among them, in step (2) and step (3), the wetting is specifically carried out by dripping an aqueous polyurethane solution with a concentration of 5wt.% to wet the fiber; the wrapping of the carbon nanotubes is specifically carried out by contacting the wetted fiber with a carbon nanotube cylinder, that is, the fiber surface is coated with the carbon nanotube cylinder; the solvent of the solvent bath is ethanol; and the drying condition is drying at 80°C for 1 hour.

[0085] The line resistance of the stretchable conductive fiber finally prepared in this embodiment is 53.5±2Ωcm -1 During stretching deformation, as the deformation rate increases, the resistance change rate increases. When the stretching deformation rate is 100%, the resistance change rate of the stretchable conductive fiber is less than 12%.

[0086] In summary, the present invention uses elastic fiber as the baseline, and coats the carbon nanotube cylinder on the pre-stretched baseline surface. After releasing the stretching force, a stretchable conductive fiber with stable resistance is obtained. When the deformation of the conductive fiber does not exceed the tensile elongation during pre-stretching, the resistance change rate is less than 15%. At the same time, the preparation method is simple, low in cost, and can be carried out continuously, which is suitable for mass production. The stretchable conductive fiber with stable resistance prepared by the method of the present invention has good bonding strength between the outer layer of carbon nanotubes and the inner layer of elastic fiber baseline, and there is no risk of falling off. The present invention can adjust the diameter and resistance of the fiber by adjusting the thickness of the baseline and the number of coatings, thereby obtaining stretchable conductive fibers of different sizes and resistances.

[0087] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for continuously preparing a stretchable conductive fiber with stable resistance, characterized in that: The steps include: S1, taking the elastic fiber as the baseline, unwinding through a feeding roller, wetting, coating with carbon nanotubes, solvent bathing, and drying, and then winding through a collecting roller. After winding, the tension is released and the elastic fiber shrinks; Wherein, the linear speeds of the feeding roller and the collecting roller are set according to the pre-stretching multiple, and the linear speed of the collecting roller is greater than the linear speed of the feeding roller; S2, the fiber obtained in the previous step is unwound through a feeding roller, and after being wetted, coated with carbon nanotubes, solvent bathed, and dried, it is taken up through a collecting roller, and after the taking-up is completed, the tension is released, and the elastic fiber shrinks; Wherein, the linear speed of the feeding roller and the collecting roller is the same as that in step S1; S3, repeat step S2 to coat multiple layers of carbon nanotubes to obtain the stretchable conductive carbon fiber with stable resistance.

2. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S1, the pre-stretching multiple is 1.5-4 times.

3. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S1 and S2, the solution used for wetting is an aqueous polyurethane solution with a mass concentration of 5%-10%.

4. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S1, the elastic fiber is a polyurethane fiber, and the fineness of the elastic fiber is 280-2280D.

5. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S1 and S2, the coating is specifically to contact the moistened elastic fiber with the carbon nanotubes to coat the surface of the elastic fiber with a layer of carbon nanotubes.

6. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S1 and S2, the carbon nanotubes are prepared by a floating catalyst chemical vapor deposition method.

7. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S1 and S2, the solvent used in the solvent bath is water, ethanol or acetone.

8. The method for continuously preparing a stretchable conductive fiber with stable resistance according to claim 1, characterized in that: In S3, the number of repetitions is 0-4 times.

9. A stretchable conductive fiber with stable resistance prepared by the preparation method according to any one of claims 1 to 8.

10. The stretchable conductive fiber with stable resistance according to claim 9, characterized in that: When the tensile deformation rate of the fiber is 50%-300%, the resistance change rate is less than 15%.

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