Dyeable high-conductive fiber and preparation method thereof

Abstract

The present invention belongs to the field of conductive fibers and discloses a dyeable, highly conductive fiber comprising a core layer and a sheath layer coated around the core layer. A primary conductive portion is provided within the core layer, and a small portion of the primary conductive portion is in direct contact with the sheath layer. The mass percentages of the core layer: sheath layer: primary conductive portion are 50-70%: 30-20%: 20-10%. The core layer is made of fully matte polyamide, the primary conductive portion comprises a carbon black / carbon nanotube synergistic conductive polyamide, and the sheath layer is made of a polyester containing aerogel and a white conductive component. In the present invention, the carbon black / carbon nanotube synergistic conductive polyamide is added to the core layer in a shaped structure and partially in direct contact with the sheath layer, thereby improving the conductive properties of the fiber and reducing the impact of carbon black on the color of the finished product. The sheath layer also incorporates an aerogel component, which forms a microporous structure on the sheath surface after subsequent alkali treatment. Due to diffuse reflection, the carbon black color of the core layer is not transmitted, thereby increasing the whiteness without adding a sunscreen to the sheath layer.

Description

Technical Field

[0001] The invention belongs to the field of conductive fibers, and in particular relates to a dyeable high-conductive fiber and a preparation method thereof. Background Art

[0002] Synthetic fibers are cheap, diverse, and easy to process, and have become widely used textile materials in daily life. However, the surface resistivity of synthetic fibers is often greater than 10 13 Ω / cm, which easily accumulates static charge during the production process, posing a significant threat to textile product quality and production safety. At the same time, with the development of science and technology and the continuous improvement of human quality of life, the adverse effects of static electricity on human production and life are becoming increasingly prominent. If only conventional polyester fibers are used, static discharge is likely to cause damage to precision electronic equipment, fires and explosions of flammable materials, and human discomfort.

[0003] Conductive fiber is a functional fiber that can reduce or eliminate static electricity generated during use. Its ability to conduct charge and discharge electricity at sharp points makes it widely used in aerospace, automotive, electronics, machinery, chemical, communications, construction, medical, textile, and other fields, and is of great significance to national defense and the national economy. In recent years, the rise of smart wearables and the development of specialized equipment have led to ever-increasing performance requirements and demand for conductive fibers, making the development and research of conductive fibers a persistent research hotspot for researchers.

[0004] Conductive fibers mainly include uniform component type, coated type, and filler / polymer composite type. Among them, filler / polymer composite conductive fibers are the most widely used due to their excellent antistatic effect, mechanical properties, durability and good wearability. Currently, conductive fiber products on the market often use carbon black as a conductive filler to improve the conductivity of the fiber, and are often prepared into a skin-core type (such as Figure 1 In a, the conductive layer is in the skin layer and the matrix is ​​in the core layer) but the finished fiber is black and cannot be dyed, even if it is prepared into a special-shaped cross-section ( Figure 1 In (c, d, e, f), the finished fiber is still gray, which still limits its application range. Figure 1 Fibers with a medium b-type cross-section (conductivity in the core layer and matrix in the skin layer) have a lighter color, but the static electricity generated on the fiber surface needs to pass through the skin matrix with poor conductivity, resulting in unsatisfactory conductivity.

[0005] As market demands for conductive fiber performance continue to rise, higher levels of carbon black are often required to meet these requirements. However, excessive carbon black added to conductive masterbatch can lead to poor filler dispersion and increased spinning difficulty, resulting in poor fiber mechanical properties and low yield. Furthermore, due to the undyability of carbon black-based conductive fibers, dyeable "white" conductive fibers have become a major development trend. While a variety of light-colored or white conductive fibers have been introduced in recent years, these fibers primarily utilize doped conductive metal compounds as the conductive filler. However, due to the limited conductivity of the filler, white conductive fibers lack the conductivity of carbon black-based conductive fibers and cannot meet the performance requirements of various applications.

[0006] For example, Chinese patent publication number CN101358387A discloses a white composite conductive fiber produced by spinning a non-conductive sheath material and a conductive core material. The non-conductive sheath material is polyester or polyamide with 0-10% TiO2 powder added, while the conductive core material is a composite of 30-80% antimony-doped tin oxide nanopowder and 20-70% copolyester or copolyamide as a carrier material. This technology uses a doped conductive metal compound as a conductive filler in the core layer, while the sheath layer is a non-conductive layer. This creates significant resistance to static electricity generated on the fiber surface being transferred to the conductive core layer, resulting in poor conductivity and limiting its application. In addition, Chinese patent publication number CN106757507A discloses a high-performance nylon-based dyeable conductive fiber. It utilizes a three-layer concentric circular structure with three components: a highly conductive carbon black component, a shielding composite component, and a white conductive component. The weight ratio of these components is 5% to 30% for the highly conductive carbon black component: 20% to 30% for the shielding composite component: 50% to 65% for the white conductive component. The inner, middle, and outer layers consist of the highly conductive carbon black component, the shielding composite component, and the white conductive component, respectively, or the inner, middle, and outer layers consist of the highly conductive carbon black component, the white conductive component, and the shielding composite component, respectively. This technology incorporates a charge transfer agent into the shielding composite component to facilitate charge transfer, but the overall amount added is small, resulting in limited benefits and lacking the desired direct contact with the conductive material. Therefore, providing a conductive fiber that combines excellent conductivity with excellent dyeability to meet diverse needs is of significant research and production significance.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a dyeable highly conductive fiber and its preparation method. The present invention uses a white conductive polyester component as the sheath and a polyamide component as the core layer. The carbon black / carbon nanotube synergistic conductive polyamide component is added to the core layer in a special-shaped structure and is partially in direct contact with the sheath. This can not only improve the conductivity of the fiber, but also reduce the impact of carbon black on the color of the finished product. An aerogel component is also introduced into the sheath. After subsequent alkali treatment, a microporous structure is formed on the surface of the sheath. Due to the effect of diffuse reflection, the carbon black color of the core layer is not transmitted through the sheath, thereby further increasing the whiteness without adding a sunscreen, enriching the choice of dyeable colors for the fiber.

[0009] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0010] The present invention provides a dyeable high-conductivity fiber, comprising a core layer and a skin layer coated on the outer periphery of the core layer, wherein a main conductive part is provided inside the core layer, and a small portion of the main conductive part is in direct contact with the skin layer, and the mass percentages of the core layer: the skin layer: the main conductive part are 50-70%: 30-20%: 20-10%; the core layer is made of fully matt polyamide, the main conductive part contains carbon black / carbon nanotube synergistic conductive polyamide, and the skin layer is made of polyester containing aerogel and a white conductive component.

[0011] In the present invention, a white conductive polyester component is selected as the sheath layer, a polyamide component is selected as the core layer, and a carbon black / carbon nanotube synergistic conductive polyamide component is added to the core layer in a special-shaped structure and partially directly contacts the sheath layer. The charge on the fiber surface can be directly transferred to the main conductive part at the core layer position, thereby improving the conductive performance of the fiber; and most of the main conductive part is wrapped by the fully matte polyamide, so that the color of most of the carbon black is obscured, reducing the influence of the carbon black on the color of the finished product.

[0012] Polyamide is chosen as the core and polyester as the sheath. On the one hand, polyamide has better conductivity than polyester, and its superior conductivity can be used to improve the conductivity and strength of the entire fiber, and the fabric woven with nylon feels softer. On the other hand, polyester has good mechanical properties, high color fastness, light resistance, and low price. After alkali treatment, the aerogel falls off to form holes, which gives the fiber the function of moisture absorption and quick drying, so that the entire fiber has the performance advantages of both components.

[0013] In this invention, a white conductive polyester component is used as the sheath, which reduces the impact of carbon black color on the finished fiber. Furthermore, an aerogel component is introduced into the sheath, creating a rougher surface and increasing the surface area. In particular, after subsequent alkali treatment, the aerogel component detaches, forming pores. This creates diffuse reflection in the fiber, preventing the carbon black color of the core from transmitting through the sheath. This reduces the fiber's transparency and increases its whiteness. The sheath wraps around the core, and the aerogel component is incorporated. This reduces the color impact of the small amount of carbon black directly contacting the sheath, even without adding a light-shielding agent. This increases the fiber's whiteness and broadens the range of dyeable colors.

[0014] In a further embodiment, in the cross section of the fiber, the ratio of the circumference of the portion of the main conductive part wrapped by the core layer to the circumference of the portion of the conductive part in direct contact with the skin layer is 4-8:1.

[0015] Preferably, the main conductive portion penetrates the core layer in the radial direction of the core layer, and both ends are in direct contact with the skin layer. From a cross-sectional view, compared with the point-like structure, the through-structure increases the path for charge transfer and improves conductivity.

[0016] In a further solution, the main conductive part is a polyamide containing carbon black and carbon nanotubes, wherein the carbon black accounts for 10-20wt% and the carbon nanotubes accounts for 4-10wt%.

[0017] Compared with pure carbon black conductive components, in order to maintain excellent conductivity, the amount of carbon black used must reach more than 30wt%. In the present invention, a small amount of carbon nanotubes is used to replace part of the carbon black in the main conductive part. The amount of carbon black is controlled to be 10-20wt% and the proportion of carbon nanotubes is 4-10wt%. The total amount of the two is significantly less than the amount of pure carbon black conductive components. Carbon nanotubes are evenly dispersed into the polyamide matrix through in-situ polymerization technology, and then blended with polyamide and carbon black to obtain carbon black / carbon nanotube conductive masterbatch. Carbon nanotubes with a high aspect ratio are conducive to long-range charge transmission. Carbon black particles will be enriched near the carbon nanotubes, and a conductive network will be formed through synergistic effects, which can effectively reduce the percolation threshold. While maintaining excellent conductive properties, the amount of carbon black can be effectively reduced, the spinnability of the fiber can be improved, and the effect of carbon black on color can be reduced.

[0018] In a further embodiment, the polyamide in the core layer and the main conductive part is selected from one or more of PA6, PA66, and PA56, preferably PA6.

[0019] In a further embodiment, the white conductive component in the skin layer accounts for 15-35 wt % and the aerogel accounts for 1-5 wt %;

[0020] In the present invention, the proportion of aerogel in the cortex is controlled to be 1-5wt%. If the content is too little, pores cannot be formed well in the cortex, and the effect on whiteness is not significant. If the content is too much, the mechanical properties of the fiber will be affected.

[0021] Preferably, the white conductive component is selected from one or more of tin dioxide, zinc oxide, and antimony tin oxide. Preferably, the particle size of the white conductive component is less than 500 nm.

[0022] In a further embodiment, the dyeable high-conductivity fibers are filaments or staple fibers;

[0023] Preferably, the staple length is 38 mm to 76 mm;

[0024] Preferably, the cortex of the staple fiber further contains PA6, and the content of PA6 in the cortex is 1-3wt%.

[0025] The fibers of the present invention can be made into either filaments or staple fibers. Short fibers are preferred because they shorten the distance that charges travel from the core layer through the carbon black conductive portion to the outside, effectively eliminating static electricity. Compared to filaments, short fibers are easier to prepare.

[0026] In addition, polyamide and polyester are not very compatible. During the subsequent use of staple fibers, the skin and core may separate due to alkali treatment. Taking this into consideration, when making staple fibers, a certain proportion of PA6 is added to the skin during the melt extrusion stage to increase compatibility and avoid peeling problems.

[0027] The present invention also provides a method for preparing the dyeable high-conductivity fiber as described above, comprising:

[0028] (1) preparing full-dull polyamide slices;

[0029] (2) preparing a polyamide masterbatch containing carbon black and carbon nanotubes;

[0030] (3) preparing polyester chips containing aerogel and white conductive components;

[0031] (4) (1) is used as the core material, (2) is used as the main conductive part material, and (3) is used as the skin material. The materials are melt-extruded and composite-spun, and then cooled and stretched to obtain dyeable high-conductive fibers.

[0032] Preferably, when preparing staple fibers, 1-3 wt% of conventional PA6 is added to the skin material during the melt extrusion stage, and the prepared polyester chips containing aerogel and white conductive components are stirred and mixed with a small amount of PA6, and then added to the screw for melt extrusion;

[0033] Preferably, the prepared highly conductive fiber or the fabric made thereof is alkali treated with 6-8% sodium hydroxide at 80-100° C. for 30 minutes.

[0034] In a further embodiment, in step (1), the polyamide is PA6, and the method for preparing the fully matt PA6 slice comprises:

[0035] Nano-scale silica powder is added to a caprolactam / water solution, stirred and mixed, ground and settled, and the upper liquid of the settled liquid is separated and filtered to obtain a suspension. The suspension is mixed with caprolactam and then subjected to a continuous ring-opening polycondensation reaction at a reaction temperature of 230-330°C for a reaction time of 15-25 hours. After multi-stage hot water extraction, drying and cooling, fully matt PA6 chips are obtained.

[0036] Preferably, the particle size of the nano-scale silicon dioxide powder is 50-500 nm, and the proportion in the slice is 10-20 wt%;

[0037] Preferably, the mass ratio of caprolactam to water is 1:1.

[0038] In a further embodiment, in step (2), the polyamide masterbatch containing carbon black and carbon nanotubes is prepared by the following method:

[0039] (1) adding carboxylated carbon nanotubes to a caprolactam / water solution, stirring and mixing, grinding, settling, separating the upper liquid of the sediment and filtering to obtain a suspension, mixing the suspension with caprolactam, and then performing a continuous ring-opening polycondensation reaction at a reaction temperature of 230-330° C. for a reaction time of 15-25 h; and then performing multi-stage hot water extraction, drying, and cooling to obtain an in-situ polymerized carbon nanotube PA6 masterbatch;

[0040] (2) PA6 and in-situ polymerized carbon nanotube PA6 are added in a certain mass ratio and stirred to mix evenly to obtain a PA6 mixture, and the PA6 mixture is mixed with carbon black, melt-extruded, dried, and pelletized to obtain a carbon black / carbon nanotube PA6 masterbatch.

[0041] In a further embodiment, in step (3), aerogel polyester chips are first prepared, and then polyester chips and aerogel polyester chips are added in a certain mass ratio and stirred and mixed uniformly to obtain a polyester mixture; then the polyester mixture and powder of the white conductive component are mixed in a certain mass ratio, melt-extruded, dried, and pelletized to obtain polyester chips containing aerogel and the white conductive component;

[0042] Preferably, the method for preparing the aerogel polyester chips comprises:

[0043] (1) mixing diol and terephthalic acid, and performing esterification reaction to obtain polyester oligomer;

[0044] (2) mixing terephthalic acid and a diol containing ultrafine aerogels, and performing an esterification reaction to obtain an aerogel-containing polyester oligomer;

[0045] (3) the polyester oligomer and the aerogel-containing polyester oligomer are stirred and blended in a mass ratio of 70-99:30-1, and then pre-polycondensed to obtain an aerogel copolyester prepolymer, and then finally polycondensed to obtain an aerogel polyester chip;

[0046] Preferably, in (1), diol and terephthalic acid are mixed in a molar ratio of alcohol to acid of 1.05-2.0 to form a slurry;

[0047] Preferably, the ultrafine aerogel is selected from one or more of SiO2, Al2O3, TiO2, MgO, Al2O3 / SiO2, B2O3 / SiO2, Fe2O3 / SiO2, and MgO / Al2O3 / SiO2;

[0048] Preferably, the particle size of the ultrafine aerogel is less than 500 nm.

[0049] In a further embodiment, the polyester used may be PET.

[0050] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0051] (1) In the present invention, a white conductive polyester component is selected as the skin layer, and a polyamide component is selected as the core layer. The carbon black / carbon nanotube synergistic conductive polyamide component with high conductivity is added to the core layer in a special-shaped structure. On the one hand, part of the carbon black / carbon nanotube synergistic conductive polyamide component is in direct contact with the skin layer, and the charge on the fiber surface can be directly transferred to the carbon black / carbon nanotube component in the core layer. The two conductive components work synergistically with each other to improve the conductive performance of the fiber; on the other hand, most of the carbon black / carbon nanotube synergistic conductive polyamide component is wrapped by the fully matte polyamide, so that the color of most of the carbon black is obscured, reducing the influence of carbon black on the color of the finished product.

[0052] In addition, polyamide is selected as the core and polyester as the sheath. On the one hand, since polyamide has better conductivity than polyester, its superior conductivity can be used to improve the conductivity and strength of the entire fiber, and the fabric made of polyamide feels softer. On the other hand, polyester has the advantages of good mechanical properties, high color fastness, light resistance, low cost, etc., and the aerogel falls off after alkali treatment to form holes, which gives the fiber the function of moisture absorption and quick drying, so that the entire fiber has the performance advantages of both components.

[0053] (2) The present invention uses a white conductive polyester component as the sheath, which not only reduces the impact of carbon black color on the finished fiber, but also introduces an aerogel component into the sheath, making the fiber surface uneven and increasing the surface area. In particular, after subsequent alkali treatment, the aerogel component can fall off to form holes, causing the fiber to produce diffuse reflection and preventing the carbon black color of the core layer from being transmitted through the sheath, thereby reducing the transparency of the fiber and increasing the whiteness. The sheath wraps the core layer and introduces the aerogel component. Without adding a light-shielding agent to the sheath, the color impact caused by the small amount of carbon black directly contacting the sheath is reduced, thereby increasing the whiteness of the fiber and enriching the selection of fiber dyeable colors.

[0054] (3) In the present invention, the main conductive portion is a small amount of carbon nanotubes that replaces part of the carbon black. The carbon nanotubes are uniformly dispersed into the polyamide matrix through in-situ polymerization technology, and then blended with polyamide and carbon black to form a carbon black / carbon nanotube synergistic conductive masterbatch. The high aspect ratio of carbon nanotubes is conducive to long-range charge transmission. The carbon black particles will be enriched near the carbon nanotubes, forming a conductive network through synergistic enhancement, which can effectively reduce the percolation threshold. While maintaining excellent conductive properties, it can effectively reduce the amount of carbon black used, improve the spinnability of the fiber, and reduce the effect of carbon black on color.

[0055] (4) The fibers of the present invention can be prepared into either filaments or staple fibers. The purpose of selecting staple fibers is to shorten the distance that the charge is transferred from the inside of the core layer to the outside through the carbon black conductive part, thereby eliminating static electricity in a timely manner. At the same time, compared with filaments, the preparation of staple fibers is simpler. In addition, the compatibility between polyamide and polyester is not very good. During the subsequent use of staple fibers, the cortex and the core layer may be separated due to alkali treatment. Taking this into account, when making staple fibers, a certain proportion of PA6 is added to the cortex to increase compatibility and avoid peeling problems.

[0056] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0058] Figure 1 It is a schematic cross-sectional view of a dyeable conductive fiber in the prior art;

[0059] Figure 2 is a schematic cross-sectional view of the dyeable conductive fiber of the present invention;

[0060] In the figure: 1. core layer; 2. skin layer; 3. main conductive part.

[0061] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0063] Detection method:

[0064] Conductive performance test: The surface resistivity of the conductive fiber was tested according to the test method in Appendix A of FZ / T 52032-2014 "Conductive Nylon Staple Fiber".

[0065] Fiber Whiteness Test: Whiteness testing is performed on treated samples in accordance with GB / T 17644-2008, "Test Method for Whiteness and Color of Textile Fibers." A spectrophotometer is used to directly measure the tristimulus values ​​(X, Y, and Z) of a sample of a certain compression density on the transmission surface of a test box. The whiteness value is calculated.

[0066] Example 1

[0067] (1) Preparation of full-dull polyamide slices:

[0068] Nano-silica powder is added to a caprolactam / water solution (1:1 by mass) and stirred, then ground and allowed to settle. The upper suspension is separated and filtered to obtain a suspension. This suspension is then mixed with caprolactam in a dynamic mixer and piped into a reactor for a continuous ring-opening polycondensation reaction at 260°C for 24 hours. After multi-stage hot water extraction, drying, and cooling, fully matte PA6 chips are obtained. The nano-silica powder has a particle size of 500 nm and accounts for 15% by weight of the chips.

[0069] (2) Preparation of carbon black / carbon nanotube synergistic PA6:

[0070] a. Preparation of in-situ polymerized carbon nanotube PA6: Carboxylated carbon nanotubes were added to a caprolactam / water solution (mass ratio 1:1) with stirring, followed by grinding and sedimentation. The upper suspension of the sediment was separated and filtered to obtain a suspension. This suspension was then mixed with caprolactam in a dynamic mixer and piped into a reactor for continuous ring-opening polycondensation at 260°C for 24 hours. After multi-stage hot water extraction, drying, and cooling, the in-situ polymerized carbon nanotube PA6 masterbatch was obtained.

[0071] b. Preparation of carbon black / carbon nanotube synergistic PA6 masterbatch

[0072] PA6 and in-situ polymerized carbon nanotubes (CNTs) PA6 were added and mixed in a specific mass ratio to form a PA6 mixture. The PA6 mixture and carbon black were then fed into a twin-screw pelletizer in a specific mass ratio through different silos, melt-extruded, dried, and pelletized to produce a carbon black / CNT synergistic masterbatch. The resulting masterbatch contained 15% carbon black by weight and 7% CNTs by weight.

[0073] (3) Preparation of polyester chips containing aerogel and white conductive components:

[0074] a. Preparation of aerogel polyester chips

[0075] ① Ethylene glycol and terephthalic acid were mixed in an alcohol-acid molar ratio of 1.5 to prepare a slurry, which was then placed in an esterification kettle for esterification reaction at a controlled temperature of 240°C to obtain polyester oligomers;

[0076] ② Then, terephthalic acid and ethylene glycol containing SiO2 ultrafine aerogel with a particle size of less than 300nm are mixed into a slurry at a molar ratio of 1.5, and then put into a small esterification kettle for esterification reaction at a controlled temperature of 240°C to obtain a polyester oligomer containing aerogel;

[0077] ③ The polyester oligomer and the aerogel-containing polyester oligomer are stirred and blended in a ratio of 80:20, and then pre-condensed at a controlled temperature of 255°C to obtain an aerogel copolyester prepolymer. Finally, the aerogel copolyester prepolymer is finally condensed at a controlled temperature of 290°C to obtain an aerogel polyester.

[0078] b. First, the corresponding PET polyester matrix and aerogel polyester chips are added in a certain mass ratio and stirred to form a polyester mixture. The polyester mixture and white conductive powder are then fed into a twin-screw pelletizer in a certain mass ratio through different silos, mixed, melted, extruded, dried, and pelletized to form the white conductive part.

[0079] The final masterbatch contains 25% white conductive powder and 2.5% aerogel by weight. The white conductive powder is tin dioxide with a particle size of less than 500nm.

[0080] (4) (1) is used as the core layer material, (2) is used as the main conductive part material, and (3) is used as the skin layer material. The ratio of the three components is (1): (2): (3) = 60:15:25, and the ratio of the circumference of the part of the main conductive part wrapped by the core layer in the fiber cross section to the circumference of the part in direct contact with the conductive part and the skin layer is 5:1. Through melt extrusion, composite spinning is carried out, and after cooling, drawing, and winding, dyeable high-conductive fiber filaments are obtained.

[0081] The prepared high-conductivity fiber filaments were treated with 8% sodium hydroxide at 100° C. for 30 minutes, and then the whiteness was tested.

[0082] Example 2

[0083] (1) Preparation of full-dull polyamide slices:

[0084] Nano-silica powder is added to a caprolactam / water solution (1:1 by mass) and stirred, then ground and allowed to settle. The upper suspension is separated and filtered to obtain a suspension. This suspension is then mixed with caprolactam in a dynamic mixer and piped into a reactor for a continuous ring-opening polycondensation reaction at 300°C for 15 hours. After multi-stage hot water extraction, drying, and cooling, fully matte PA6 chips are obtained. The nano-silica powder has a particle size of 100 nm and accounts for 10% by weight of the chips.

[0085] (2) Preparation of carbon black / carbon nanotube synergistic PA6:

[0086] a. Preparation of in-situ polymerized carbon nanotube PA6: Carboxylated carbon nanotubes were added to a caprolactam / water solution (mass ratio 1:1) with stirring, followed by grinding and sedimentation. The upper suspension of the sediment was separated and filtered to obtain a suspension. This suspension was then mixed with caprolactam in a dynamic mixer and piped into a reactor for continuous ring-opening polycondensation at 300°C for 15 hours. After multi-stage hot water extraction, drying, and cooling, the in-situ polymerized carbon nanotube PA6 masterbatch was obtained.

[0087] b. Preparation of carbon black / carbon nanotube synergistic PA6 masterbatch

[0088] PA6 and in-situ polymerized carbon nanotubes (CNTs) PA6 were added and mixed in a specific mass ratio to form a PA6 mixture. The PA6 mixture and carbon black were then fed into a twin-screw pelletizer in a specific mass ratio through different silos, melt-extruded, dried, and pelletized to produce a carbon black / CNT synergistic masterbatch. The resulting masterbatch contained 10% carbon black and 8% CNTs by weight.

[0089] (3) Preparation of polyester chips containing aerogel and white conductive components:

[0090] a. Preparation of aerogel polyester chips

[0091] ① Ethylene glycol and terephthalic acid were mixed in an alcohol-acid molar ratio of 2.0 to prepare a slurry, which was then placed in an esterification kettle for esterification reaction at a controlled temperature of 230°C to obtain a polyester oligomer;

[0092] ② Then, terephthalic acid and ethylene glycol containing ultrafine aerogels of Al2O3 / SiO2 (mass percentage 20%:80%) with a particle size of less than 500nm were mixed into a slurry at an alcohol-acid molar ratio of 2.0, and then placed in a small esterification kettle for esterification reaction at a controlled temperature of 245°C to obtain a polyester oligomer containing aerogels;

[0093] ③ The polyester oligomer and the aerogel-containing polyester oligomer are stirred and blended in a ratio of 95:5, and then pre-condensed at a temperature of 260°C to obtain an aerogel copolyester prepolymer. Finally, the aerogel copolyester prepolymer is finally condensed at a temperature of 295°C to obtain an aerogel polyester.

[0094] b. First, the corresponding PET polyester matrix and aerogel polyester chips are added in a certain mass ratio and stirred to form a polyester mixture. The polyester mixture and white conductive powder are then fed into a twin-screw pelletizer in a certain mass ratio through different silos, mixed, melted, extruded, dried, and pelletized to form the white conductive part.

[0095] The resulting masterbatch contains 35% white conductive powder and 1% aerogel. The white conductive powder is zinc oxide, with a particle size of less than 500nm.

[0096] (3) (1) is used as the core layer material, (2) is used as the main conductive part material, and (3) is used as the skin layer material. The ratio of the three components is (1): (2): (3) = 50:20:30, and the ratio of the circumference of the part of the main conductive part wrapped by the core layer in the fiber cross section to the circumference of the part in direct contact with the conductive part and the skin layer is 4:1. Through melt extrusion, composite spinning is carried out, and after cooling, drawing, and winding, dyeable high-conductive fiber filaments are obtained.

[0097] The prepared high-conductivity fiber filaments were alkali-treated with 6% sodium hydroxide at 80° C. for 30 minutes, and then the whiteness was tested.

[0098] Example 3

[0099] (1) Preparation of full-dull polyamide slices:

[0100] Nano-silica powder is added to a caprolactam / water solution (1:1 by mass) and stirred, then ground and allowed to settle. The upper suspension is separated and filtered to obtain a suspension. This suspension is then mixed with caprolactam in a dynamic mixer and piped into a reactor for a continuous ring-opening polycondensation reaction at 230°C for 25 hours. After multi-stage hot water extraction, drying, and cooling, fully matte PA6 chips are obtained. The nano-silica powder has a particle size of 50 nm and accounts for 20% by weight of the chips.

[0101] (2) Preparation of carbon black / carbon nanotube synergistic PA6:

[0102] a. Preparation of in-situ polymerized carbon nanotube PA6: Carboxylated carbon nanotubes were added to a caprolactam / water solution (mass ratio 1:1) with stirring, followed by grinding and sedimentation. The upper suspension of the sediment was separated and filtered to obtain a suspension. This suspension was then mixed with caprolactam in a dynamic mixer and piped into a reactor for continuous ring-opening polycondensation at 230°C for 25 hours. After multi-stage hot water extraction, drying, and cooling, the in-situ polymerized carbon nanotube PA6 masterbatch was obtained.

[0103] b. Preparation of carbon black / carbon nanotube synergistic PA6 masterbatch

[0104] PA6 and in-situ polymerized carbon nanotubes (CNTs) PA6 were added and mixed in a specific mass ratio to form a PA6 mixture. The PA6 mixture and carbon black were then fed into a twin-screw pelletizer in a specific mass ratio through different silos, melt-extruded, dried, and pelletized to produce a carbon black / CNT synergistic masterbatch. The resulting masterbatch contained 20% carbon black and 4% CNTs by weight.

[0105] (3) Preparation of polyester chips containing aerogel and white conductive components:

[0106] a. Preparation of aerogel polyester chips

[0107] ① Ethylene glycol and terephthalic acid were mixed in an alcohol-acid molar ratio of 1.2 to prepare a slurry, which was then placed in an esterification kettle for esterification reaction at a controlled temperature of 245°C to obtain polyester oligomers;

[0108] ② Then, terephthalic acid and ethylene glycol containing ultrafine aerogels of MgO / Al2O3 / SiO2 (mass percentage of 15%:15%:70%) with a particle size of less than 400 nm were mixed at an alcohol-acid molar ratio of 1.2 to form a slurry, which was then placed in a small esterification kettle for esterification reaction at a controlled temperature of 250°C to obtain a polyester oligomer containing aerogels;

[0109] ③ The polyester oligomer and the aerogel-containing polyester oligomer were stirred and blended in a ratio of 85:15, and then pre-condensed at a temperature of 265°C to obtain an aerogel copolyester prepolymer. Finally, the aerogel copolyester prepolymer was finally condensed at a temperature of 290°C to obtain an aerogel polyester.

[0110] b. First, the corresponding PET polyester matrix and aerogel polyester chips are added in a certain mass ratio and stirred to form a polyester mixture. The polyester mixture and white conductive powder are then fed into a twin-screw pelletizer in a certain mass ratio through different silos, mixed, melted, extruded, dried, and pelletized to form the white conductive part.

[0111] The resulting masterbatch contains 35% white conductive powder and 1.2% aerogel by weight. The white conductive powder is zinc oxide, with a particle size of less than 500nm.

[0112] (4) (1) is used as the core material, (2) is used as the main conductive part material, and (3) is used as the skin material. The ratio of the three components is (1): (2): (3) = 70:10:20, and the ratio of the circumference of the portion of the main conductive part wrapped by the core layer in the fiber cross section to the circumference of the portion of the conductive part directly in contact with the skin layer is 8:1. Through melt extrusion, composite spinning is carried out, and after cooling, drawing, and cutting, dyeable high-conductive fiber staple fibers are obtained. 3wt% conventional PA6 is also added to the skin material during the melt extrusion stage. The specific steps are as follows: the polyester chips containing aerogel and white conductive components prepared earlier are stirred and mixed with a small amount of PA6, and then added to the screw for melt extrusion.

[0113] The prepared high-conductivity fiber staple was alkali-treated with 7% sodium hydroxide at 90° C. for 30 minutes, and then the whiteness was tested.

[0114] Example 4

[0115] (1) Preparation of full-dull polyamide slices:

[0116] Nano-silica powder is added to a caprolactam / water solution (1:1 by mass) and stirred, then ground and allowed to settle. The upper suspension is separated and filtered to obtain a suspension. This suspension is then mixed with caprolactam in a dynamic mixer and piped into a reactor for a continuous ring-opening polycondensation reaction at 260°C for 24 hours. After multi-stage hot water extraction, drying, and cooling, fully matte PA6 chips are obtained. The nano-silica powder has a particle size of 500 nm and accounts for 15% by weight of the chips.

[0117] (2) Preparation of carbon black / carbon nanotube synergistic PA6:

[0118] a. Preparation of in-situ polymerized carbon nanotube PA6: Carboxylated carbon nanotubes were added to a caprolactam / water solution (mass ratio 1:1) with stirring, followed by grinding and sedimentation. The upper suspension of the sediment was separated and filtered to obtain a suspension. This suspension was then mixed with caprolactam in a dynamic mixer and piped into a reactor for continuous ring-opening polycondensation at 260°C for 24 hours. After multi-stage hot water extraction, drying, and cooling, the in-situ polymerized carbon nanotube PA6 masterbatch was obtained.

[0119] b. Preparation of carbon black / carbon nanotube synergistic PA6 masterbatch

[0120] PA6 and in-situ polymerized carbon nanotubes (CNTs) PA6 were added and mixed in a specific mass ratio to form a PA6 mixture. The PA6 mixture and carbon black were then fed into a twin-screw pelletizer in a specific mass ratio through different silos, melt-extruded, dried, and pelletized to produce a carbon black / CNT synergistic masterbatch. The resulting masterbatch contained 15% carbon black by weight and 7% CNTs by weight.

[0121] (3) Preparation of polyester chips containing aerogel and white conductive components:

[0122] a. Preparation of aerogel polyester chips

[0123] ① Ethylene glycol and terephthalic acid were mixed in an alcohol-acid molar ratio of 1.5 to prepare a slurry, which was then placed in an esterification kettle for esterification reaction at a controlled temperature of 240°C to obtain polyester oligomers;

[0124] ② Then, terephthalic acid and ethylene glycol containing SiO2 ultrafine aerogel with a particle size of less than 300nm are mixed into a slurry at a molar ratio of 1.5, and then put into a small esterification kettle for esterification reaction at a controlled temperature of 240°C to obtain a polyester oligomer containing aerogel;

[0125] ③ The polyester oligomer and the aerogel-containing polyester oligomer are stirred and blended in a ratio of 80:20, and then pre-condensed at a controlled temperature of 255°C to obtain an aerogel copolyester prepolymer. Finally, the aerogel copolyester prepolymer is finally condensed at a controlled temperature of 290°C to obtain an aerogel polyester.

[0126] b. First, the corresponding PET polyester matrix and aerogel polyester chips are added in a certain mass ratio and stirred to form a mixture. The mixture and white conductive powder are then fed into a twin-screw pelletizer in a certain mass ratio through different silos for mixing, melt extrusion, drying, and pelletizing to obtain the white conductive part.

[0127] The resulting masterbatch contains 25% by weight of white conductive powder and 2.5% by weight of aerogel. The white conductive powder is tin dioxide, with a particle size of less than 500 nm.

[0128] (4) (1) is used as the core material, (2) is used as the main conductive part material, and (3) is used as the skin material. The ratio of the three components is (1): (2): (3) = 60:15:25, and the ratio of the circumference of the part of the main conductive part wrapped by the core layer to the circumference of the part of the conductive part directly in contact with the skin layer is 5:1. Through melt extrusion, composite spinning is carried out, and after cooling, drawing, and cutting, a dyeable high-conductive short fiber is obtained. 1wt% of conventional PA6 is also added to the skin material during the melt extrusion stage. The specific steps are as follows: the polyester chips containing aerogel and white conductive components prepared earlier are stirred and mixed with a small amount of PA6, and then added to the screw for melt extrusion.

[0129] The prepared high-conductivity fiber staple was alkali-treated with 8% sodium hydroxide at 100° C. for 30 minutes, and then the whiteness was tested.

[0130] The performance test results of the dyeable high-conductivity fibers prepared in various examples are shown in Table 1 below.

[0131] Table 1

[0132] Example Example 1 Example 2 Example 3 Example 4 Surface resistivity / Ω 2.56×10E6 9.87×10E5 8.43×10E6 3.28×10E6 Whiteness / % 75.8465 68.1287 79.3272 74.4216

[0133] Comparative Example 1 Effect of the contact circumference between the main conductive part and the cortex in the fiber cross section on the performance

[0134] This comparative example refers to the preparation method of Example 1, with the difference that: in each group, the main conductive part in the fiber cross section is not in direct contact with the cortex (three concentric circles), or the ratio of the circumference of the part of the main conductive part in the fiber cross section wrapped by the core layer to the circumference of the part in direct contact with the cortex is 17:1, 1:1. The test results of the prepared fibers are shown in Table 2 below.

[0135] Table 2

[0136] Contact perimeter ratio No direct contact with the cortex 17:1 5:1 (Example 1) 1:1 Surface resistivity / Ω 8.42×10E7 4.28×10E7 2.56×10E6 1.84×10E6 Whiteness / % 86.1721 84.2539 75.8465 61.2786

[0137] Analysis of results: Compared with Example 1, when the ratio of the circumference of the portion of the main conductive part wrapped by the core layer in the fiber cross section to the circumference of the portion in direct contact between the conductive part and the cortex is 17:1, that is, the circumference of the contact between the main conductive part and the cortex is relatively small, although the whiteness is improved, the surface resistivity is one order of magnitude lower, and the small contact part increases the difficulty of spinning, and it may even occur that the main conductive part of some spun fibers does not contact the cortex, resulting in a decrease in conductivity; when the ratio of the circumference of the portion of the main conductive part wrapped by the core layer in the fiber cross section to the circumference of the portion in direct contact between the conductive part and the cortex is 1:1, that is, the contact part between the main conductive part and the cortex is relatively large, the whiteness is significantly reduced, and the effect on the improvement of conductivity is relatively small.

[0138] Comparative Example 2 Effect of the Synergistic Effect of Carbon Black and Carbon Nanotubes

[0139] This comparative example refers to the preparation method of Example 1, with the difference that the content of carbon black and carbon nanotubes in the main conductive part of each group is different. The test results of the prepared fibers are shown in the following table:

[0140] Table 3

[0141]

[0142]

[0143] Results Analysis: Compared to Example 1 (Group 3), when the fibers contained only carbon black or carbon nanotubes, with all other conditions unchanged (Groups 2 and 4), the resulting fibers exhibited significantly reduced electrical conductivity. Only when the carbon black content reached 35% did the resulting fibers achieve conductivity similar to that of Example 1, but with a significant decrease in whiteness. Furthermore, when the carbon nanotube content exceeded the 4-10 wt% range specified in this application, the carbon nanotubes exhibited poor dispersion, making the preparation of in-situ polymerized carbon nanotube polyamide difficult and preventing subsequent fiber preparation.

[0144] Effect of aerogel content in the third skin layer of the comparative example

[0145] This comparative example refers to the preparation method of Example 1, with the difference that the aerogel content in the skin layer is 0% (no aerogel) and 10wt% (excessive proportion, greater than 5wt%). The test results of the prepared fibers are as follows:

[0146] Table 4

[0147]

[0148] Analysis of the results: When the cortex does not contain aerogel, light scattering after irradiation on the fiber surface is less and the extinction effect is weakened, the color inside the fiber is easy to show through, resulting in a decrease in whiteness; when the aerogel content in the cortex is 7% (i.e., when the proportion is too large), the conductive performance is close to that of Example 1, and the effect of improving whiteness is not obvious. However, excessive aerogel content leads to a significant decrease in the mechanical properties of the fiber and greatly increases the difficulty of aerogel polyester chips and subsequent fiber preparation. When the addition amount reaches 10wt%, no fiber can be obtained.

[0149] Comparative Example 4

[0150] This comparative example refers to the preparation method of Example 1, except that the polyester in the skin layer is replaced by PA6, and the polyamide in the core layer and the main conductive part is replaced by polyester.

[0151] Result analysis: Replacing the polyamide in the core layer and the main conductive part with polyester increases the difficulty of preparation because carbon nanotubes are prone to agglomeration during the synthesis of in situ polymerized polyester chips. Even if in situ polymerized polyester chips are prepared, the amount added is relatively small, resulting in poor final conductive performance. Replacing the polyester in the skin layer with PA6 cannot obtain the advantages of polyester such as good mechanical properties, high color fastness, light resistance, and low cost.

[0152] Comparative Example 5

[0153] This comparative example refers to the preparation method of Example 1, except that the prepared fibers are not subjected to alkali treatment.

[0154] Table 5

[0155] Whether the fiber is alkali treated after preparation Not alkali treated Alkali treatment (Example 1) Surface resistivity / Ω 2.75×10E6 3.28×10E6 Whiteness / % 67.4922 74.4216

[0156] Analysis of the results: When the fiber is not treated with alkali, the fiber surface is relatively smooth and no holes are formed, resulting in weak diffuse reflection of light and the color of the internal carbon black is easy to show through; when the fiber is treated with alkali, holes are formed on the fiber surface. Due to the enhanced diffuse reflection, the carbon black color of the core layer will not be transmitted from the cortex, which reduces the transparency of the fiber and increases the whiteness.

[0157] Comparative Example 6

[0158] This comparative example refers to the preparation method of Example 4, except that 1 wt % of conventional PA6 is not added to the skin layer.

[0159] The test results of the prepared fibers are as follows:

[0160] Table 6

[0161] Should 1wt% conventional PA6 be added to the cortex? No Add (Example 4) Surface resistivity / Ω 1.16×10E6 3.28×10E6 Whiteness / % 64.7248 74.4216

[0162] Analysis of results: When 1wt% conventional PA6 is not added to the sheath and staple fibers are made, due to the incompatibility between polyester and polyamide, the alkaline solution easily enters between the fiber sheath and core, causing the sheath and core layers to separate. Although the conductive performance is improved, the color of the main conductive part of the core layer that is not covered is exposed, resulting in a significant decrease in whiteness.

[0163] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present invention can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A dyeable highly conductive fiber, characterized in that: The invention comprises a core layer and a skin layer wrapped around the outer periphery of the core layer, a main conductive part is provided inside the core layer, and a small part of the main conductive part is in direct contact with the skin layer, and the mass percentages of the core layer: the skin layer: the main conductive part are 50-70%: 30-20%: 20-10%; the core layer is made of fully matt polyamide, the main conductive part is made of polyamide containing carbon black / carbon nanotubes for synergistic conductivity, and the skin layer is made of polyester containing aerogel and white conductive components; the main conductive part penetrates the core layer in the radial direction of the core layer, and both ends are in direct contact with the skin layer.

2. The dyeable highly conductive fiber according to claim 1, characterized in that In the cross section of the fiber, the ratio of the circumference of the portion of the main conductive part wrapped by the core layer to the circumference of the portion of the conductive part in direct contact with the skin layer is 4-8:

1.

3. The dyeable highly conductive fiber according to claim 1, characterized in that The main conductive part is polyamide containing carbon black and carbon nanotubes, wherein the carbon black accounts for 10-20wt% and the carbon nanotubes accounts for 4-10wt%.

4. The dyeable highly conductive fiber according to any one of claims 1 to 3, characterized in that: The polyamide in the core layer and the main conductive part is selected from one or more of PA6, PA66 and PA56.

5. The dyeable highly conductive fiber according to any one of claims 1 to 3, characterized in that: The polyamide in the core layer and the main conductive part is PA6.

6. The dyeable highly conductive fiber according to any one of claims 1 to 3, characterized in that: The white conductive component in the skin layer accounts for 15-35 wt %, and the aerogel accounts for 1-5 wt %.

7. The dyeable highly conductive fiber according to any one of claims 1 to 3, characterized in that: The white conductive component is selected from one or more of tin dioxide, zinc oxide, and antimony tin oxide.

8. The dyeable highly conductive fiber according to claim 7, characterized in that The particle size of the white conductive component is less than 500 nm.

9. The dyeable highly conductive fiber according to any one of claims 1 to 3, characterized in that: The dyeable highly conductive fibers are either filaments or staple fibers.

10. The dyeable highly conductive fiber according to claim 9, characterized in that The staple length is 38mm-76mm.

11. The dyeable highly conductive fiber according to claim 9, characterized in that The skin layer of the staple fiber also contains PA6, with a content of 1-3wt%.

12. A method for preparing the dyeable high-conductivity fiber according to any one of claims 1 to 11, characterized in that: include: (1) Preparation of fully matt polyamide chips; (2) Preparation of polyamide masterbatch containing carbon black and carbon nanotubes; (3) Preparation of polyester chips containing aerogel and white conductive components; (4) (1) is used as the core material, (2) is used as the main conductive part material, and (3) is used as the skin material. The materials are melt-extruded and composite-spun, and then cooled and drawn to obtain dyeable high-conductive fibers.

13. The preparation method according to claim 12, characterized in that When preparing staple fibers, 1-3 wt% conventional PA6 is added to the skin material during the melt extrusion stage. The prepared polyester chips containing aerogel and white conductive components are stirred and mixed evenly with a small amount of PA6, and then added to the screw for melt extrusion.

14. The preparation method according to claim 12, characterized in that The prepared high-conductive fiber or the fabric made thereof is alkali-treated by using 6-8% sodium hydroxide at 80-100° C. for 30 minutes.

15. The preparation method according to claim 12, characterized in that In step (1), the polyamide is PA6, and the method for preparing the fully matte PA6 slice includes: Nano-scale silica powder is added to a caprolactam / water solution, stirred and mixed, ground and settled, and the upper liquid of the sediment is separated and filtered to obtain a suspension. The suspension is mixed with caprolactam and then subjected to a continuous ring-opening polycondensation reaction at a reaction temperature of 230-330°C and a reaction time of 15-25 hours. After multi-stage hot water extraction, drying and cooling, fully matt PA6 chips are obtained.

16. The preparation method according to claim 15, characterized in that The particle size of nano-scale silica powder is 50-500nm, and its proportion in the slice is 10-20wt%.

17. The preparation method according to claim 15, characterized in that The mass ratio of caprolactam to water is 1:

1.

18. The preparation method according to claim 12, characterized in that: In step (2), the polyamide masterbatch containing carbon black and carbon nanotubes is prepared by: (1) Adding carboxylated carbon nanotubes to a caprolactam / water solution, stirring and mixing, grinding, settling, separating the upper liquid of the sedimentation liquid and filtering to obtain a suspension, mixing the suspension with caprolactam, and then performing a continuous ring-opening polycondensation reaction at a reaction temperature of 230-330°C and a reaction time of 15-25h; then, performing multi-stage hot water extraction, drying, and cooling to obtain an in-situ polymerized carbon nanotube PA6 masterbatch; (2) PA6 and in-situ polymerized carbon nanotube PA6 are added in a certain mass ratio and stirred to obtain a PA6 mixture. The PA6 mixture is mixed with carbon black, melt-extruded, dried, and pelletized to obtain a carbon black / carbon nanotube PA6 masterbatch.

19. The preparation method according to claim 12, characterized in that: In step (3), aerogel polyester chips are first prepared, and then polyester chips and aerogel polyester chips are added in a certain mass ratio and stirred and mixed evenly to obtain a polyester mixture; then the polyester mixture and powder of the white conductive component are mixed in a certain mass ratio, melt-extruded, dried, and pelletized to obtain polyester chips containing aerogel and white conductive components.

20. The preparation method according to claim 19, characterized in that The preparation method of the aerogel polyester chip comprises: (1) Mixing diol and terephthalic acid, and performing esterification reaction to obtain polyester oligomer; (2) mixing terephthalic acid and diol containing ultrafine aerogel, and performing esterification reaction to obtain aerogel-containing polyester oligomer; (3) The polyester oligomer and the aerogel-containing polyester oligomer are stirred and blended in a mass ratio of 70-99:30-1, and then pre-condensed to obtain an aerogel copolyester prepolymer, and then finally condensed to obtain an aerogel polyester chip.

21. The preparation method according to claim 20, characterized in that In (1), diol and terephthalic acid are mixed in a molar ratio of alcohol to acid of 1.05-2.0 to prepare a slurry.

22. The preparation method according to claim 20, characterized in that The ultrafine aerogel is selected from one or more of SiO2, Al2O3, TiO2, MgO, Al2O3 / SiO2, B2O3 / SiO2, Fe2O3 / SiO2, and MgO / Al2O3 / SiO2.

23. The preparation method according to claim 22, characterized in that The particle size of the ultrafine aerogel is less than 500 nm.

Images