Solution coating type high-strength high-conductivity high-wear-resistance monofilament and preparation method thereof

Abstract

The application discloses a solution coating type high-strength high-conductivity high-wear-resistance monofilament and a preparation method thereof. The monofilament comprises an inner layer and an outer layer, the outer layer wraps the inner layer, the inner layer is a nylon monofilament, and the outer layer is a conductive coating. The conductive coating comprises the following components by weight: 80-92 parts of nylon resin, 3-7 parts of conductive carbon black, 1-3 parts of surface modified carbon nanotubes, 2-6 parts of conductive graphene, and 3-8 parts of (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid. The high-strength high-wear-resistance high-conductivity monofilament prepared by the application selects a nylon monofilament as the inner layer structure, thereby meeting the requirement of high strength of the monofilament. On the other hand, the conductive coating liquid can partially dissolve the surface of the nylon monofilament after being coated on the nylon monofilament, and the conductive coating can be tightly combined with the nylon monofilament after being dried. The low content of formic acid ensures that the coating liquid cannot quickly dissolve the nylon monofilament, so that the prepared conductive monofilament has relatively high strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of monofilament, in particular to a solution coating type high-strength high-conductivity high-wear-resistant monofilament and a preparation method thereof. BACKGROUND

[0002] With the development of industrial production, functional fibers play an important role in the fields of textile, medical treatment, communication and other national production, and the research on conductive fibers is paid more and more attention. The conductive fibers can be widely applied in the fields of antistatic, electromagnetic shielding, electric heating function, electronic communication and the like according to their conductivity. The products have excellent performance and are less affected by the environment.

[0003] The preparation methods of the conductive fibers mainly include solution spinning method, blending spinning method and surface coating method.

[0004] The solution spinning method is to dissolve the base resin and conductive filler in a proper solvent to prepare a spinning solution, and then to obtain the fiber through solution spinning. The conductive filler includes metal, carbon material (including conductive carbon black, carbon nanotube and conductive graphene) and conductive polymer material. The main problem of this method is that the existence of the filler will affect the spinning stability of the polymer solution, the imitativeness is poor, the spinning process is difficult to control, and large-scale industrial production is difficult.

[0005] The blending spinning method is to directly add the conductive filler into the base resin to prepare the conductive fiber through melt spinning. This method needs to add a large amount of filler to realize the uniform dispersion of the filler in the base resin, which leads to low mechanical properties of the fiber and low conductivity.

[0006] The surface coating method generally mixes the conductive filler with the resin solution or other adhesives to prepare a coating liquid, and then coats the liquid on the surface of the fiber. The fiber prepared by this method has good conductivity and high mechanical properties. However, the conductive filler on the surface is easy to fall off due to friction, and the conductivity is difficult to maintain for a long time. SUMMARY

[0007] In view of the above defects or deficiencies in the prior art, it is desirable to provide a solution coating type high-strength high-conductivity high-wear-resistant monofilament and a preparation method thereof.

[0008] In a first aspect, a solution coating type high-strength high-conductivity high-wear-resistant monofilament is provided, which comprises an inner layer and an outer layer, the outer layer wrapping the inner layer, the inner layer being a nylon monofilament, and the outer layer being a conductive coating layer, the composition of the conductive coating layer comprising:

[0009]

[0010] and the sum of the weights of the nylon resin, the conductive carbon black, the surface-modified carbon nanotube, the conductive graphene, and the (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 100.

[0011] In a second aspect, a preparation method of the solution coating type high-strength high-conductivity high-wear-resistance monofilament is provided, and the method comprises the following steps:

[0012] Step one: preparation of surface-modified carbon nanotubes,

[0013] The dried carbon nanotubes are ultrasonically dispersed in deionized water to form a carbon nanotube dispersion liquid with a mass fraction of 1.5%, and the silane coupling agent KH-570 is dispersed in anhydrous ethanol to prepare a solution with a mass fraction of 20%. After being uniformly mixed, the solution is poured into the carbon nanotube dispersion liquid and ultrasonically treated for 30 minutes. The amount of the silane coupling agent KH-570 is 5% of the mass of the carbon nanotubes,

[0014] The mixture is stirred and refluxed at 90°C for 24 hours, and then filtered and washed to obtain the silane-modified carbon nanotubes.

[0015] The silane-modified carbon nanotubes, deionized water, p-styrene sulfonic acid, and initiator are mixed and dispersed at a mass ratio of 1.5:100:(1-4):(0.0075-0.03), ultrasonically treated for 2 hours, stirred and refluxed at a set reaction temperature for 24 hours, filtered, washed with water, and dried to obtain the surface-modified carbon nanotubes.

[0016] Step two: preparation of a conductive coating liquid,

[0017] The surface-modified carbon nanotubes are ultrasonically dispersed in the (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid aqueous solution, and concentrated to obtain a carbon nanotube-conductive polymer aqueous solution with a solid content of 10%.

[0018] The nylon resin is dissolved in a mixed solution of formic acid / acetic acid / water, and the conductive carbon black, the conductive graphene, and the carbon nanotube-conductive polymer aqueous solution are sequentially added under stirring to obtain a preliminary conductive coating liquid. The preliminary conductive coating liquid is ground by a sand mill at a rotation speed of 4000 r / min for 3-5 hours to obtain a final conductive coating liquid.

[0019] In the final conductive coating liquid, the mass percentage of the solid content composed of the nylon resin, the conductive carbon black, the surface-modified carbon nanotube, the conductive graphene, and the (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 10%, the mass percentage of deionized water is 20%, the mass percentage of acetic acid is 30%, and the mass percentage of formic acid is 40%.

[0020] Step three: preparation of a solution coating type high-strength high-wear-resistance high-conductivity monofilament,

[0021] The final conductive coating liquid is coated on the nylon monofilament surface by using a monofilament coating machine, dried by a hot air oven at high temperature, and wound to obtain high-strength, high-wear-resistance and high-conductivity monofilaments, with a monofilament feeding speed of 70 m / min and an oven temperature of 160 DEG C.

[0022] Compared with the prior art, the application has the following advantages:

[0023] 1. The high-strength, high-wear-resistance and high-conductivity monofilaments prepared by the application select nylon monofilaments as the inner layer structure, meeting the requirement of high strength of the monofilaments, and the conductive coating liquid can partially dissolve the surface of the nylon monofilaments after being coated on the nylon monofilaments, so that the conductive coating layer can be tightly combined with the nylon monofilaments after drying, and the low content of formic acid ensures that the coating liquid cannot quickly dissolve the nylon monofilaments, so that the prepared conductive monofilaments have high strength.

[0024] 2. The proportion of graphene, conductive carbon black and conductive carbon nanotubes in the conductive coating layer is low, and part of the conductive fillers is replaced by conductive polymers, so that the prepared fibers have stronger wear resistance.

[0025] 3. The carbon nanotubes are surface modified by grafting polystyrene sulfonic acid, so that an organic-inorganic hybrid structure is formed between the carbon nanotubes and the conductive polymers, and by means of the high aspect ratio of the carbon nanotubes, a good conductive path can be established among the conductive carbon black, carbon nanotubes, graphene and conductive polymers, so that the fibers have good conductive effect under the condition of low content of conductive carbon materials. BRIEF DESCRIPTION OF DRAWINGS

[0026] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0027] Figure 1 The solution coating type high-strength, high-conductivity and high-wear-resistance monofilament preparation method flow chart in the embodiment. DETAILED DESCRIPTION

[0028] The application will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and not to limit the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for ease of description.

[0029] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the accompanying drawings and embodiments.

[0030] The embodiment claims a solution coating type high-strength high-conductivity high-wear-resistant monofilament, the monofilament comprises an inner layer and an outer layer, the outer layer wraps the inner layer, the inner layer is a nylon monofilament, the outer layer is a conductive coating, the composition of the conductive coating is:

[0031]

[0032] and the sum of the weights of the nylon resin, the conductive carbon black, the surface modified carbon nanotube, the conductive graphene and the (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 100.

[0033] The monofilament claimed in the embodiment is realized by a two-layer structure, the inner layer uses a nylon monofilament to meet the requirement of high strength of the monofilament, and the proportion of graphene, conductive carbon black and conductive carbon nanotube in the conductive coating is low, part of the conductive filler is replaced by a polymer, so that the prepared fiber has stronger wear resistance, and the surface modification of the conductive carbon nanotube by grafting polystyrene sulfonic acid enables the formation of an organic-inorganic hybrid structure between the carbon nanotube and the conductive polymer, and by virtue of the high aspect ratio of the carbon nanotube, a good conductive path can be established among the conductive carbon black, the carbon nanotube, the graphene and the conductive polymer, thereby ensuring that the fiber has good conductive effect under the condition of low content of conductive carbon material.

[0034] Further, the nylon monofilament is prepared by melt spinning of one or more of polycaprolactam (PA6), polyhexamethylene adipamide (PA66) and caprolactam-hexamethylene adipamide copolymer,

[0035] The original diameter of the nylon monofilament is 0.08-1mm, and the monofilament strength is 3-5.9cN / dtex.

[0036] In the embodiment, nylon monofilament is selected as the inner layer to form the core layer, which has high strength and can ensure that the prepared supporting monofilament has strong monofilament strength while having the conductive ability of the outer layer structure, and the nylon material can be a single material or a mixture of multiple materials, which does not affect the strength.

[0037] Further, the nylon resin is one or more of polycaprolactam (PA6) and caprolactam-hexamethylene adipamide copolymer, and the relative viscosity of the nylon resin ranges from 2.5 to 5.

[0038] In the embodiment, the outer layer structure wrapping the inner layer is provided, which is set as a conductive coating to enable the formed monofilament to have conductive performance, and the conductive coating is prepared by mixing nylon resin with other materials, so that the outer layer conductive coating prepared by the nylon resin can better combine with the inner layer of nylon, so that the outer layer and the inner layer are not easy to separate.

[0039] Further, the conductive carbon black has a primary particle size of 15-50 nm. The conductive carbon black selected in this embodiment has a particle size that is not too large, and can better form a conductive coating liquid.

[0040] Further, the surface-modified carbon nanotube is prepared by surface grafting modification of p-styrene sulfonic acid on the carbon nanotube,

[0041] The mass percentage content of the poly-p-styrene sulfonic acid in the surface-modified carbon nanotube is 3-8%, the carbon nanotube is one or several of a multi-arm carbon nanotube or a single-arm carbon nanotube, the carbon nanotube contains a hydroxyl group on the surface, has a diameter of 3-20 nm, and has a length of 2-50 μm.

[0042] In this embodiment, the carbon nanotube is surface-modified by p-styrene sulfonic acid, so that an organic-inorganic hybrid structure is formed between the carbon nanotube and the conductive polymer. With the high aspect ratio of the carbon nanotube, a good conductive path can be formed in the conductive coating liquid and other materials, so that the fiber has good conductive effect under the condition of a low content of the conductive carbon material.

[0043] Further, the specific surface area of the conductive graphene is 200-600 m 2 / g, and the particle size is 2-20 μm.

[0044] Further, the raw material of the (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid is an aqueous solution of (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid, the solid content mass fraction is 1.0-1.5%, and the ratio of (3,4-ethylenedioxythiophene) to poly-p-styrene sulfonic acid is 1:2.5-5.

[0045] This embodiment also provides a solution coating type high-strength high-conductive high-wear-resistant monofilament preparation method, which comprises the following steps:

[0046] Step one: preparation of the surface-modified carbon nanotube,

[0047] The dried carbon nanotube is ultrasonically dispersed in deionized water to form a carbon nanotube dispersion liquid with a mass fraction of 1.5%, and the carbon nanotube dispersion liquid is stirred at 90°C for 24 hours.

[0048] The mixture is stirred and refluxed at 90°C for 24 hours, and then is subjected to suction filtration and washing to obtain the silane-modified carbon nanotube.

[0049] The silane-modified carbon nanotube, deionized water, p-styrene sulfonic acid and initiator are mixed and dispersed in a mass ratio of 1.5:100:(1-4):(0.0075-0.03), ultrasonic treatment is performed for 2 hours, stirring reflux is performed at a set reaction temperature for 24 hours, and then the surface-modified carbon nanotube is obtained by filtration, water washing and drying;

[0050] Step two: preparation of a conductive coating solution,

[0051] The surface-modified carbon nanotube is ultrasonic dispersed in a (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid aqueous solution, and a carbon nanotube-conductive polymer aqueous solution with a solid content of 10% is obtained by concentration;

[0052] The nylon resin is dissolved in a mixed solution of formic acid / acetic acid / water, and the conductive carbon black, conductive graphene and the carbon nanotube-conductive polymer aqueous solution are sequentially added under stirring to obtain a preliminary conductive coating solution, and the preliminary conductive coating solution is ground by a sand mill at a rotation speed of 4000 r / min for 3-5 hours to obtain a final conductive coating solution,

[0053] In the final conductive coating solution, the solid content mass percentage of the nylon resin, the conductive carbon black, the surface-modified carbon nanotube, the conductive graphene and the (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid is 10%, the mass percentage of deionized water is 20%, the mass percentage of acetic acid is 30%, and the mass percentage of formic acid is 40%,

[0054] Step three: preparation of a solution-coated high-strength high-wear-resistance high-conductivity monofilament,

[0055] The final conductive coating solution is coated on the surface of a nylon monofilament by using a monofilament coating machine, and a high-strength high-wear-resistance high-conductivity monofilament is prepared by high-temperature drying and winding in a hot air oven, with a monofilament feeding speed of 70 m / min and an oven temperature of 160℃.

[0056] In the preparation method provided in the embodiment, the surface-modified carbon nanotube is first prepared, the carbon nanotube is modified by a silane coupling agent and grafted with polystyrene sulfonic acid for surface modification, so that an organic-inorganic hybrid structure is formed between the carbon nanotube and the conductive polymer;

[0057] Subsequently, the surface-modified carbon nanotubes are ultrasonically dispersed in a (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid aqueous solution, and nylon resins dissolved with formic acid and acetic acid are added, as well as conductive carbon black and conductive graphene, to form a conductive coating liquid. The surface-modified carbon nanotubes form good conductive paths with the corresponding conductive carbon black and conductive graphene, so that the outer layer structure formed has good conductive effect. In this embodiment, stirring is performed at a set temperature for a certain time, and ultrasonic setting time, which are both to make the mixture more uniform, so that the prepared monofilament has better conductive effect.

[0058] Further, in step one, the mass percentage content of polystyrene sulfonic acid in the surface-modified carbon nanotubes is 3-8%; the carbon nanotubes are one or more of multi-armed carbon nanotubes or single-armed carbon nanotubes, and the surface of the carbon nanotubes contains hydroxyl groups, with a diameter of 3-20 nm and a length of 2-50 μm;

[0059] The initiator includes one or more of ammonium persulfate, potassium persulfate, sodium sulfite-ammonium persulfate system, and sodium thiosulfate-potassium persulfate system.

[0060] Further, in step two, the original particle size of the conductive carbon black is 15-50 nm;

[0061] The specific surface area of the conductive graphene is 200-600 m 2 / g, and the particle size is 2-20 μm;

[0062] The solid content mass fraction of (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid in the (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid aqueous solution is 1.0-1.5%, and the ratio of (3,4-ethylenedioxythiophene) to polystyrene sulfonic acid is 1:2.5-5.

[0063] Further, in step three, the nylon monofilament is prepared by melt spinning of one or more of polycaprolactam (PA6), poly(hexamethylene adipate) (PA66), and caprolactam-hexamethylene adipate copolymer, with an original diameter of 0.08-1 mm and a monofilament strength of 3-5.9 cN / dtex.

[0064] The monofilament structure provided in this embodiment is formed in an inner-outer layered manner, and the inner layer is a nylon monofilament, which meets the requirement of high monofilament strength. The solvent configured by water / formic acid / acetic acid in a certain mass ratio can well disperse and dissolve the base resin and the filler, and can partially dissolve the surface of the nylon monofilament after the conductive coating liquid is coated on the nylon monofilament. After drying, the conductive coating layer can be tightly combined with the nylon monofilament. The low formic acid content ensures that the coating liquid cannot quickly dissolve the nylon monofilament, so that the prepared conductive monofilament has high strength.

[0065] According to the above method, the following five examples are given:

[0066] Example 1:

[0067] Step one: preparation of surface modified carbon nanotubes

[0068] Multi-armed carbon nanotubes with a diameter of 3-7 nm and a length of 5-12 μm were ultrasonically dispersed in deionized water to form a carbon nanotube dispersion with a mass fraction of 1.5%, and ultrasonic dispersion was performed for 2 hours. 5% of silane coupling agent KH-570 relative to the mass of carbon nanotubes was dispersed in anhydrous ethanol to prepare a solution with a mass fraction of 20%, and after mixing uniformly, it was poured into the carbon nanotube dispersion and ultrasonic dispersion was performed for another 30 minutes. The above mixture was stirred and refluxed at 90°C for 24 hours, and after suction filtration, washing and drying, silane-modified carbon nanotubes were obtained. The silane-modified carbon nanotubes, deionized water, p-styrene sulfonic acid and ammonium persulfate were mixed and dispersed in a mass ratio of 1.5:100:1:0.0075, ultrasonic dispersion was performed for 2 hours, and stirring and refluxing were performed at 60°C for 24 hours. After suction filtration, water washing and drying, surface-modified carbon nanotubes were obtained. The mass percentage content of poly-p-styrene sulfonic acid in the surface-modified carbon nanotubes was 3%.

[0069] Step two: preparation of conductive coating solution

[0070] 1 part by weight of the surface-modified carbon nanotubes prepared in step one was ultrasonically dispersed in a (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid aqueous solution containing 3 parts by weight of a solid content of 1.3% and a ratio of (3,4-ethylenedioxythiophene) to poly-p-styrene sulfonic acid of 1:2.5, and after concentration, a carbon nanotube-conductive polymer aqueous solution with a solid content of 10% was obtained. 86 parts by weight of PA6 nylon resin with a relative viscosity of 2.7 was dissolved in a mixed solution of formic acid / acetic acid / water, and under stirring conditions, 7 parts by weight of conductive carbon black with a diameter of 30 nm, 3 parts by weight of conductive graphene with a specific surface area of 200-400 m 2 / g and a particle size of 10-15 μm, and the prepared carbon nanotube-conductive polymer aqueous solution were added in sequence to obtain a conductive coating solution. In the conductive coating solution, the solid content of the nylon resin, conductive carbon black, surface-modified carbon nanotubes, conductive graphene and (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid was 10%, and by adjusting the solvent ratio, the mass percentage of deionized water was 20%, the mass percentage of acetic acid was 30%, and the mass percentage of formic acid was 40%. The conductive coating solution was ground by a sand mill at a speed of 4000 r / min for 3-5 hours to obtain the final conductive coating solution.

[0071] Step three: preparation of solution-coated high-strength high-conductivity high-wear-resistant monofilament

[0072] The conductive coating solution prepared in step two was coated on the surface of PA6 monofilament with a diameter of 0.08 mm and a strength of 5.0 cN / dtex using a monofilament coating machine, dried in a hot air oven at high temperature, and wound to obtain a high-strength, high-conductivity, and high-wear-resistance monofilament. The monofilament feeding speed was 70 m / min, and the oven temperature was 160°C. The obtained monofilament had a strength of 4.8 cN / dtex and a resistivity of 1.3 x 10 3 Ω·cm, and the resistivity increased by 7.7% after 100 industrial washes. 3 Ω·cm, and the resistivity increased by 7.7% after 100 industrial washes.

[0073] Example 2:

[0074] The other conditions were the same as in Example 1, except that the monofilament used in step three had a diameter of 0.5 mm and a strength of 3.8 cN / dtex, and was prepared by solution coating to obtain a conductive monofilament with a resistivity of 8.3 x 10 3 Ω·cm, and the resistivity increased by 8.4% after 100 industrial washes. 3 Ω·cm, and the resistivity increased by 8.4% after 100 industrial washes.

[0075] Example 3:

[0076] Step one: preparation of surface-modified carbon nanotubes

[0077] Multi-armed carbon nanotubes with a diameter of 12-19 nm and a length of 35-47 μm were ultrasonically dispersed in deionized water to form a carbon nanotube dispersion with a mass fraction of 1.5%, and 5% silane coupling agent KH-570 relative to the mass of the carbon nanotubes was dispersed in anhydrous ethanol to form a solution with a mass fraction of 20%. After mixing and ultrasonic treatment for 30 minutes, the mixture was stirred and refluxed at 90°C for 24 hours. After suction filtration, washing, and drying, the silane-modified carbon nanotubes were obtained. The silane-modified carbon nanotubes, deionized water, p-styrene sulfonic acid, and an ammonium persulfate-sodium sulfite initiation system were mixed and dispersed at a mass ratio of 1.5:100:4:0.03, ultrasonically treated for 2 hours, stirred and refluxed at 30°C for 24 hours, suction filtered, washed with water, and dried to obtain surface-modified carbon nanotubes. The mass percentage content of poly-p-styrene sulfonic acid in the surface-modified carbon nanotubes was 8%.

[0078] Step two: preparation of a conductive coating solution

[0079] The surface modified carbon nanotube prepared in step one is dispersed in 3 parts by weight in an aqueous solution of (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid having a solid content of 1.3% and a ratio of (3,4-ethylenedioxythiophene) to polystyrene sulfonic acid of 1:2.5 in 8 parts by weight, and concentrated to obtain an aqueous solution of carbon nanotube-conductive polymer having a solid content of 10%; 80 parts by weight of a caprolactam- hexamethylene adipamide copolymer nylon resin having a relative viscosity of 4.0 is dissolved in a mixed solution of formic acid / acetic acid / water, and 3 parts by weight of conductive carbon black having a diameter of 15 nm, 6 parts by weight of conductive graphene having a specific surface area of 400-600 m 2 / g and a particle size of 2-10 μm, and the prepared aqueous solution of carbon nanotube-conductive polymer are added under stirring to obtain a conductive coating liquid. In the conductive coating liquid, the solid content of the nylon resin, the conductive carbon black, the surface modified carbon nanotube, the conductive graphene and the (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 10%, and the mass percentage of deionized water is 20%, the mass percentage of acetic acid is 30% and the mass percentage of formic acid is 40% by adjusting the proportions of the solvents. The conductive coating liquid is ground in a sand mill at a rotational speed of 4000 r / min for 3-5 hours to obtain a final conductive coating liquid.

[0080] Step three: preparation of solution-coated high-strength high-conductivity high-wear-resistance monofilament

[0081] The conductive coating liquid prepared in step two is coated on the surface of PA66 monofilament having a diameter of 0.08 mm and a strength of 5.9 cN / dtex by using a monofilament coating machine, dried in a hot air oven at high temperature and wound to obtain a high-strength high-conductivity high-wear-resistance monofilament. The feeding speed of the monofilament is 70 m / min and the oven temperature is 160°C. The obtained conductive monofilament has a strength of 5.6 cN / dtex and a resistivity of 142 Ω·cm, and after 100 times of industrial washing, the resistivity is 147 Ω·cm, with an increase of 3.5%.

[0082] Example 4:

[0083] The other conditions are the same as in example 3, except that in step one, the silane-modified carbon nanotube, deionized water, p-styrene sulfonic acid and sodium sulfite-ammonium persulfate initiation system are mixed and dispersed in a mass ratio of 1.5:100:1:0.0075, ultrasonically for 2 hours, stirred and refluxed at 30°C for 24 hours, filtered, washed with water and dried to obtain surface-modified carbon nanotube. The mass percentage of polystyrene sulfonic acid in the surface-modified carbon nanotube is 3%. The conductivity of the conductive monofilament prepared by solution coating is 6.4×10 2 Ω·cm, and after 100 times of industrial washing, the resistivity is 6.7 Ω·cm, with an increase of 4.6%.

[0084] Example 5:

[0085] The multi-arm carbon nanotubes with diameter of 8-14 nm and length of 22-36 μm were ultrasonically dispersed in deionized water to form a carbon nanotube dispersion with mass fraction of 1.5%, and 5% silane coupling agent KH-570 relative to the mass of the carbon nanotubes was dispersed in anhydrous ethanol to form a solution with mass fraction of 20%, which was then mixed uniformly and poured into the carbon nanotube dispersion, followed by ultrasonic treatment for 30 minutes. The mixture was stirred and refluxed at 90°C for 24 hours, and then filtered and washed to obtain silane-modified carbon nanotubes. The silane-modified carbon nanotubes, deionized water, p-styrene sulfonic acid, and a potassium sulfite initiation system were mixed and dispersed in a mass ratio of 1.5:100:2:0.015, ultrasonically treated for 2 hours, stirred and refluxed at 30°C for 24 hours, filtered, washed with water, and dried to obtain surface-modified carbon nanotubes. The mass percentage of poly-p-styrene sulfonic acid in the surface-modified carbon nanotubes was 4.7%.

[0086] Step two: preparation of conductive coating solution

[0087] One part by weight of the surface-modified carbon nanotubes prepared in step one was ultrasonically dispersed in a (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid aqueous solution containing three parts by weight of (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid with solid content of 1.0% and a ratio of (3,4-ethylenedioxythiophene) to poly-p-styrene sulfonic acid of 1:5, and concentrated to obtain a carbon nanotube-conductive polymer aqueous solution with solid content of 10%; 92 parts by weight of PA6 nylon resin with relative viscosity of 4.8 was dissolved in a mixed solution of formic acid / acetic acid / water, and 2 parts by weight of conductive carbon black with diameter of 50 nm, 2 parts by weight of conductive graphene with specific surface area of 200-300 m 2 / g and particle size of 14-20 μm, and the prepared carbon nanotube-conductive polymer aqueous solution were added under stirring to obtain a conductive coating solution. In the conductive coating solution, the solid content of the nylon resin, conductive carbon black, surface-modified carbon nanotubes, conductive graphene, and (3,4-ethylenedioxythiophene)-poly-p-styrene sulfonic acid was 10%, and the mass percentage of deionized water was 20%, the mass percentage of acetic acid was 30%, and the mass percentage of formic acid was 40% by adjusting the proportions of solvents. The conductive coating solution was ground by a sand mill at a rotation speed of 4000 r / min for 3-5 hours to obtain a final conductive coating solution.

[0088] Step three: preparation of solution-coated high-strength high-conductivity high-wear-resistance monofilament

[0089] The conductive coating solution prepared in step two is coated on the surface of PA6 / PA66 mixed monofilament with a diameter of 0.1 mm and a strength of 5.2 cN / dtex and a mass ratio of 3 / 7 by using a monofilament coating machine, dried in a hot air oven at high temperature, and wound to obtain a high-strength, high-conductivity, and high-wear-resistance monofilament. The monofilament feeding speed is 70 m / min, and the oven temperature is 160°C. The obtained monofilament has a strength of 4.8 cN / dtex and a resistivity of 7.9 x 10 3 Ω·cm. After 100 times of industrial washing, the resistivity of the monofilament is 8.6 x 10 3 Ω·cm, and the resistivity increases by 8.8%.

[0090] Example 6:

[0091] Other conditions are the same as in Example 5, except that PA6 monofilament with a diameter of 1.0 mm and a strength of 3.2 cN / dtex is used. The obtained conductive monofilament has a strength of 2.9 cN / dtex and a volume resistivity of 8.5 x 10 4 Ω·cm. After 100 times of industrial washing, the volume resistivity of the monofilament is 9.3 x 10 4 Ω·cm, and the volume resistivity increases by 9.4%.

[0092] The above examples show that the monofilament provided in the present application has high strength and good conductivity.

[0093] The above description is merely preferred embodiments of the present application and a description of the principles of the technology used. Those skilled in the art should understand that the scope of the application disclosed in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and also covers other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features disclosed in the present application (but not limited to) having similar functions to form technical solutions.

Claims

1. A solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament, characterized in that, The monofilament comprises an inner layer and an outer layer, the outer layer wrapping the inner layer. The inner layer is a nylon monofilament, and the outer layer is a conductive coating. The conductive coating is composed of: 80-92 parts by weight of nylon resin; 3-7 parts by weight of conductive carbon black; Surface-modified carbon nanotubes, 1-3 parts by weight; Conductive graphene 2-6 parts by weight; 3-8 parts by weight of (3,4-ethylenedioxythiophene)-poly(p-styrenesulfonic acid); Furthermore, the total weight of the nylon resin, the conductive carbon black, the surface-modified carbon nanotubes, the conductive graphene, and the (3,4-ethylenedioxythiophene)-poly(p-phenylenesulfonic acid) is 100. The surface-modified carbon nanotubes are prepared by surface grafting carbon nanotubes with styrene sulfonic acid. The mass percentage content of styrene sulfonic acid in the surface-modified carbon nanotubes is 3-8%. The carbon nanotubes are one or more of multi-arm carbon nanotubes or single-arm carbon nanotubes. The surface of the carbon nanotubes contains hydroxyl groups, and the diameter is 3-20 nm and the length is 2-50 μm.

2. The solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 1, characterized in that, The nylon monofilament is prepared by melt spinning from one or more of polycaprolactam (PA6), polyhexamethylene adipamide (PA66), and caprolactam-hexamethylene adipamide copolymer. The original diameter of the nylon monofilament is 0.08-1 mm, and the monofilament strength is 3-5.9 cN / dtex.

3. The solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 1, characterized in that, The nylon resin is one or more of polycaprolactam (PA6) and caprolactam-hexamethylenediamine copolymer, and the relative viscosity range of the nylon resin is 2.5-5.

4. The solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 1, characterized in that, The original particle size of the conductive carbon black is 15-50 nm.

5. The solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 1, characterized in that, The conductive graphene has a specific surface area of ​​200-600 m². 2 / g, with a particle size of 2-20 μm.

6. The solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 1, characterized in that, The raw material for the (3,4-ethylenedioxythiophene)-poly(p-styrene sulfonic acid) is an aqueous solution of (3,4-ethylenedioxythiophene)-poly(p-styrene sulfonic acid), with a solid content mass fraction of 1.0-1.5% and a ratio of (3,4-ethylenedioxythiophene) to poly(p-styrene sulfonic acid) of 1:2.5-5.

7. A method for preparing a solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Preparation of surface-modified carbon nanotubes The dried carbon nanotubes were ultrasonically dispersed in deionized water to form a 1.5% (w / w) carbon nanotube dispersion. The dispersion was ultrasonicated for 2 hours. A 20% (w / w) solution of silane coupling agent KH-570 was prepared by dispersing it in anhydrous ethanol. This solution was then mixed thoroughly and poured into the carbon nanotube dispersion. The mixture was then ultrasonicated for another 30 minutes. The amount of silane coupling agent KH-570 used was 5% of the mass of the carbon nanotubes. The above mixture was stirred and refluxed at 90°C for 24 hours, then filtered and washed to obtain silane-modified carbon nanotubes. Silane-modified carbon nanotubes, deionized water, p-styrene sulfonic acid, and initiator were mixed and dispersed in a mass ratio of 1.5:100:(1-4):(0.0075-0.03), sonicated for 2 hours, stirred and refluxed at the set reaction temperature for 24 hours, filtered, washed with water, and dried to obtain surface-modified carbon nanotubes. Step 2: Preparation of conductive coating solution. The surface-modified carbon nanotubes were ultrasonically dispersed in an aqueous solution of (3,4-ethylenedioxythiophene)-poly(p-styrene sulfonic acid), and then concentrated to obtain an aqueous solution of carbon nanotubes-conductive polymer with a solid content of 10%. Nylon resin was dissolved in a mixed solution of formic acid / acetic acid / water. Conductive carbon black, conductive graphene, and the carbon nanotube-conductive polymer aqueous solution were added sequentially under stirring to obtain a preliminary conductive coating solution. This preliminary conductive coating solution was then ground in a sand mill at 4000 r / min for 3-5 hours to obtain the final conductive coating solution. In the final conductive coating solution, the solid content (by mass percentage) of nylon resin, conductive carbon black, surface-modified carbon nanotubes, conductive graphene, and (3,4-ethylenedioxythiophene)-poly(p-phenylenesulfonic acid) is 10%, the mass percentage of deionized water is 20%, the mass percentage of acetic acid is 30%, and the mass percentage of formic acid is 40%. Step 3: Preparation of solution-coated high-strength, high-wear-resistant, and high-conductivity monofilaments. The final conductive coating liquid was applied to the surface of nylon monofilament using a monofilament coating machine, and then dried and wound in a hot air oven at high temperature to obtain a high-strength, high-wear-resistant, and high-conductivity monofilament. The monofilament feeding speed was 70 m / min, and the oven temperature was 160 ℃.

8. A method for preparing a solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 7, characterized in that, In step one, the mass percentage content of poly(p-styrene sulfonic acid) in the surface-modified carbon nanotubes is 3-8%; the carbon nanotubes are one or more of multi-arm carbon nanotubes or single-arm carbon nanotubes, the surface of the carbon nanotubes contains hydroxyl groups, the diameter is 3-20 nm, and the length is 2-50 μm. The initiator includes one or more of the following: ammonium persulfate, potassium persulfate, sodium sulfite-ammonium persulfate system, and sodium thiosulfate-potassium persulfate system.

9. The method for preparing solution-coated high-strength, high-conductivity, and high-wear-resistant monofilaments according to claim 7, characterized in that, The original particle size of the conductive carbon black mentioned in step two is 15-50 nm; The conductive graphene has a specific surface area of ​​200-600 m². 2 / g, with a particle size of 2-20 μm; The solid content of (3,4-ethylenedioxythiophene)-poly(p-styrene sulfonic acid) in the aqueous solution of (3,4-ethylenedioxythiophene)-poly(p-styrene sulfonic acid) is 1.0-1.5% by mass, and the ratio of (3,4-ethylenedioxythiophene) to poly(p-styrene sulfonic acid) is 1:2.5-5.

10. The method for preparing solution-coated high-strength, high-conductivity, and high-wear-resistant monofilament according to claim 7, characterized in that, The nylon monofilament described in step three is prepared by melt spinning of one or more of polycaprolactam (PA6), polyhexamethylene adipamide (PA66), and caprolactam-hexamethylene adipamide copolymer. The original diameter of the nylon monofilament is 0.08-1 mm, and the monofilament strength is 3-5.9 cN / dtex.

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