Conductive polyester fiber and its preparation method and application

Abstract

The present invention discloses a conductive polyester fiber and a preparation method and application thereof, relating to the field of functional fibers. The conductive polyester fiber has a sheath-core structure, wherein a core layer component comprises a first polyethylene terephthalate, and a sheath layer component comprises a second polyethylene terephthalate, a first polyamide elastomer and a conductive carbon black masterbatch, wherein the conductive carbon black masterbatch comprises a second polyamide elastomer and conductive carbon black. The difference in zero shear viscosity between each polyamide elastomer and each polyethylene terephthalate is controlled so that the melt viscosity of the polyamide elastomer is lower than that of the polyethylene terephthalate. During the spinning process, the low-viscosity polyamide elastomer easily diffuses to the fiber surface, driving the conductive carbon black to be enriched on the fiber surface. The hard segment in the polyamide elastomer crystallizes during the stretching and drawing process, prompting the conductive carbon black to transfer to and be enriched in the amorphous region. Practice has shown that the fiber of the present invention has both excellent conductive properties and properties such as long-term stability and excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the field of functional fibers, and in particular to a conductive polyester fiber and a preparation method and application thereof. Background Art

[0002] Polyethylene terephthalate fiber (PET fiber) is one of the most widely produced and widely used synthetic fibers. Its strength, chemical resistance, light resistance, and heat resistance make it a key player in the textile, apparel, and home textile industries. However, the current polyester fiber market is highly competitive, characterized by significant homogeneity and low net profits, posing significant challenges to polyester fiber manufacturers.

[0003] To meet the diverse needs of the market, developing functional polyester fibers is one of the effective ways to enhance corporate competitiveness. For example, in the fields of security protection, camouflage and reconnaissance materials, energy harvesting, and smart wearables, developing conductive polyester fibers with properties such as softness, good conductivity, and bend recovery will have promising application prospects. However, current conductive polyester fibers still have the following problems to varying degrees:

[0004] (1) There is insufficient durability, and the conductive performance is easy to drop significantly during use. For example, patent CN112981959A provides a sol-type conductive polyester fiber, which overcomes the surface polarity of polyester fiber and uses sericin to finish polyester fabric, doping Fe 3+ While this improves its antistatic and conductive properties, the poor durability of the sol layer can degrade the fiber's conductivity during use. Similarly, using electroplating or chemical plating to create a conductive layer on the surface of polyester fibers also presents the problem of insufficient conductivity.

[0005] (2) There is insufficient conductivity, or excessive conductive material is added in pursuit of high conductivity, which results in a significant decrease in the fiber's spinnability, strength and other properties, making it unfavorable for practical application. For example, patent CN107354534A uses a composite spinning process to prepare a conductive composite fiber with a core-skin structure. The core layer is fiber-grade polyester, and the skin layer is a low-melting-point polymer and conductive masterbatch. The conductive material is evenly dispersed in the radial direction of the fiber skin layer. To ensure a certain conductivity, more conductive material can only be added to form contact resistance and construct a conductive path, which to a certain extent affects the spinnability and strength of the fiber.

[0006] Therefore, developing a conductive polyester fiber that has excellent conductivity, long-lasting stability, and excellent mechanical properties has become a technical challenge that needs to be overcome urgently. Summary of the Invention

[0007] The purpose of the present invention is to overcome one or more deficiencies in the prior art and provide an improved conductive polyester fiber that has excellent conductivity, long-lasting stability, excellent mechanical properties, and the like, with a relatively small amount of conductive material added.

[0008] The present invention also provides a method for preparing conductive polyester fibers and their application in preparing safety protection materials, camouflage reconnaissance materials, energy collection materials, and intelligent wearable materials.

[0009] In order to achieve the above object, a technical solution adopted by the present invention is:

[0010] A conductive polyester fiber having a sheath-core structure, wherein the core component of the sheath-core structure comprises a first polyethylene terephthalate, and the sheath component comprises a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch, wherein the raw materials of the conductive carbon black masterbatch comprise the second polyamide elastomer and conductive carbon black, and the conductive carbon black has terminal carboxyl groups;

[0011] Under the same test temperature conditions, the zero shear viscosity of the first polyamide elastomer is recorded as η1, the zero shear viscosity of the second polyamide elastomer is recorded as η2, the zero shear viscosity of the first polyethylene terephthalate and the zero shear viscosity of the second polyethylene terephthalate are both recorded as η3, and the zero shear viscosity is measured by a steady-state shear rheology experiment in units of Pa·s; when the test temperature is 275-290°C, η1, η2 and η3 satisfy the following conditions: 35Pa·s≤η3-η1≤280Pa·s, 50Pa·s≤η3-η2≤300Pa·s.

[0012] According to some preferred aspects of the present invention, under the same test temperature conditions, the zero shear viscosity of the first polyamide elastomer is greater than or equal to the zero shear viscosity of the second polyamide elastomer, which is more conducive to the enrichment of conductive carbon black on the fiber surface.

[0013] In some preferred embodiments of the present invention, the number average molecular weight of the first polyamide elastomer is 18,000-20,000 g / mol.

[0014] In some preferred embodiments of the present invention, the number average molecular weight of the second polyamide elastomer is 15,000-18,000 g / mol.

[0015] According to some preferred aspects of the present invention, under the same test temperature conditions, the zero shear viscosity of the first polyethylene terephthalate is the same as the zero shear viscosity of the second polyethylene terephthalate.

[0016] In some preferred embodiments of the present invention, the number average molecular weight of the first polyethylene terephthalate and the number average molecular weight of the second polyethylene terephthalate are respectively 20,000-30,000 g / mol.

[0017] According to some preferred aspects of the present invention, the first polyamide elastomer and the second polyamide elastomer are respectively polyether polyamide elastomers.

[0018] In the present invention, compared with polyester polyamide elastomer, the use of polyether polyamide elastomer can give the fiber better flexibility, the fiber feels softer and more comfortable, and can also improve the performance in low-temperature environments, so that the fiber can still maintain good elasticity and flexibility in low-temperature environments, and is not easy to harden or become brittle. In addition, the water resistance and dyeing performance are improved. Analysis shows that the ether bond in the system has a beneficial anti-hydrolysis effect, and the higher polarity makes it easier to interact with dye molecules, thereby improving the dyeing performance.

[0019] Furthermore, the polyether polyamide elastomer consists of a crystalline hard segment and a non-crystalline soft segment, the crystalline hard segment is polycaprolactam with a number average molecular weight of 3000-4000 g / mol, and the non-crystalline soft segment is polyethylene glycol with a number average molecular weight of 4000-5000 g / mol.

[0020] In some preferred embodiments of the present invention, based on 100 parts of the total amount of the skin layer components, the second polyethylene terephthalate accounts for 40-50 parts, the first polyamide elastomer accounts for 15-20 parts, and the conductive carbon black masterbatch accounts for 30-45 parts.

[0021] According to some preferred aspects of the present invention, based on 100 parts of the total amount of the conductive polyester fiber, the skin layer component accounts for 20-50 parts, and the core layer component accounts for 50-80 parts.

[0022] In some embodiments of the present invention, the conductive carbon black masterbatch is prepared by mixing and extruding the second polyamide elastomer and the conductive carbon black.

[0023] According to some preferred and specific aspects of the present invention, the particle size of the conductive carbon black is 30-200 nm.

[0024] According to some preferred aspects of the present invention, the conductive carbon black accounts for 40%-60% of the raw materials of the conductive carbon black masterbatch in terms of mass percentage.

[0025] In some embodiments of the present invention, the volume specific resistance of the conductive polyester fiber is 30~10 4Ω·cm, fineness is 1~10dtex, breaking strength is greater than 3.5cN / dtex, and breaking elongation is 15%~35%.

[0026] Another technical solution provided by the present invention is a method for preparing the conductive polyester fiber described above, the method comprising: using a melt spinning process to spin a core layer component and a skin layer component into a conductive polyester fiber with a skin-core structure, wherein the spinning process parameters include: a melt extrusion temperature of the core layer component of 285-300°C, a melt extrusion temperature of the skin layer component of 270-285°C, a spinning assembly temperature of 275-290°C, a hot drawing temperature of 140-160°C, and a hot drawing ratio of 5-8 times.

[0027] Another technical solution provided by the present invention is: an application of the conductive polyester fiber described above in the preparation of safety protection materials, camouflage reconnaissance materials, energy collection materials, and smart wearable materials.

[0028] In the present invention, the "first" and "second" in the first polyethylene terephthalate, the second polyethylene terephthalate, the first polyamide elastomer, and the second polyamide elastomer have no order of precedence and are only used to distinguish the polyethylene terephthalate or polyamide elastomer used in different components.

[0029] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0030] Based on the defects of current conductive polyester fibers such as insufficient durability, insufficient conductivity, or reduced spinnability and strength of the fibers in pursuit of high conductivity, the present invention innovatively provides an improved conductive polyester fiber, which has a sheath-core structure and uses a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch (containing a second polyamide elastomer and conductive carbon black containing a carboxyl group) as sheath components, and a first polyethylene terephthalate as a core component. The difference in zero shear viscosity between each polyamide elastomer and each polyethylene terephthalate is controlled so that the melt viscosity of the polyamide elastomer is lower than that of the polyethylene terephthalate. During the spinning process, under the action of shear and stretching flow fields, the low-viscosity polyamide elastomer is easily Diffusion on the fiber surface drives the conductive carbon black to be enriched on the fiber surface (during melt spinning, the system is in a high-temperature molten state, the thermal motion of the molecules is intensified, the polyamide elastomer molecules with low viscosity are more likely to move in the melt, and can overcome the intermolecular forces to diffuse to the fiber surface. In addition, the polyamide elastomer with low viscosity and polyethylene terephthalate are thermodynamically immiscible, which will cause microphase separation and migration to the fiber surface. Through the interaction between the amide bond and the carboxyl group on the conductive carbon black, the conductive carbon black is enriched on the fiber surface). At the same time, the polyamide hard segment in the polyamide elastomer will crystallize during the stretching and drawing process (accompanied by cooling). In the crystallized state, the volume exclusion of the crystals will cause the conductive carbon black to transfer to the amorphous region and be enriched in the amorphous soft segment area.

[0031] Taking into account the combined effects of the above aspects, the conductive carbon black in the fiber of the present invention is more concentrated and more fully overlapped with each other, so that better or even better conductive performance can be achieved with a smaller amount of addition, thereby significantly reducing the amount of conductive filler added, while also reducing the impact on the strength of the fiber, and the fiber has good spinnability and long-term stability. DETAILED DESCRIPTION

[0032] The above scheme is further described below in conjunction with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are generally the conditions in routine experiments.

[0033] Unless otherwise specified in the following examples, all raw materials were purchased commercially or prepared by conventional methods in the art. In the following examples, conductive carbon black was purchased from Cabot, brand Vulcan® XC72R (oxidatively modified), which contains terminal carboxyl groups.

[0034] Example 1: This example provides a conductive polyester fiber and a preparation method thereof. The conductive polyester fiber has a sheath-core structure, wherein the core layer component of the sheath-core structure is a first polyethylene terephthalate, and the sheath layer component is composed of a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch;

[0035] Taking the total mass of the conductive polyester fiber as 100%, the skin component accounts for 20% and the core component accounts for 80%;

[0036] Based on the total mass of the skin layer components being 100%, the second polyethylene terephthalate accounts for 40%, the first polyamide elastomer accounts for 15%, and the conductive carbon black masterbatch accounts for 45%;

[0037] The raw materials of the conductive carbon black masterbatch are composed of a second polyamide elastomer and conductive carbon black. Calculated by weight percentage, the conductive carbon black accounts for 40% of the raw materials of the conductive carbon black masterbatch.

[0038] The first polyethylene terephthalate and the second polyethylene terephthalate were both produced by Jiangsu Guowang High-Tech Fiber Co., Ltd., and both had a number average molecular weight of 20,000 g / mol; the first polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 4050 and a number average molecular weight of 20,000 g / mol; the second polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 3060 and a number average molecular weight of 15,000 g / mol;

[0039] The conductive carbon black masterbatch was prepared by the following method: a second polyamide elastomer (grade 3060) was dried at 100°C to a moisture content of less than 50 ppm, and then pre-mixed with the conductive carbon black Vulcan® XC72R (oxidatively modified) at high speed. The mixture was then melt-blended and extruded through a twin-screw extruder, and pelletized after water cooling to obtain the conductive carbon black masterbatch. The temperatures of zones I to VII of the twin-screw extruder were 175°C, 180°C, 205°C, 205°C, 203°C, 200°C, and 195°C, respectively.

[0040] The preparation method of the conductive polyester fiber comprises:

[0041] The first polyethylene terephthalate and the second polyethylene terephthalate are dried in a low dew point drying oven at 165°C to a moisture content of less than 50 ppm; the first polyamide elastomer and the conductive carbon black masterbatch are dried in a low dew point drying oven at 120°C to a moisture content of less than 50 ppm;

[0042] The dried first polyethylene terephthalate is used as the core layer component and is melted by screw extruder I (the temperatures of zones I to IV are 285°C, 288°C, 286°C, and 286°C, respectively) and extruded by metering pump I (the temperature of the metering pump is 286°C). The dried second polyethylene terephthalate, the first polyamide elastomer, and the conductive carbon black masterbatch are used as the skin layer component and are melted by screw extruder II (the temperatures of zones I to IV are 270°C, 274°C, 272°C, and 272°C, respectively) and extruded by metering pump II (the temperature of the metering pump is 272°C). The melts of the components pass through the core-skin composite spinning assembly (the temperature of the assembly is 275°C. Under this temperature condition, the second polyethylene terephthalate is melted by screw extruder II (the temperature of the zone I to IV is 270°C, 274°C, 272°C, and 272°C, respectively). The zero-shear viscosity of the glycol ester is 50 Pa·s higher than that of the second polyamide elastomer, and the zero-shear viscosity of the second polyethylene terephthalate is 38 Pa·s higher than that of the first polyamide elastomer), is extruded, cooled by side-blowing at 20°C and a wind speed of 0.6 m / s, and then bundled and oiled. It then passes through pre-stretching (the first hot roller temperature is 140°C and the speed is 800 m / min, the second hot roller temperature is 140°C and the speed is 1200 m / min), main stretching (the third hot roller temperature is 145°C and the speed is 4000 m / min), heat setting (temperature is 140°C and the speed is 4000 m / min), and finally wound at 4050 m / min to make a conductive polyester fiber.

[0043] Example 2: This example provides a conductive polyester fiber and a preparation method thereof. The conductive polyester fiber has a sheath-core structure, wherein the core layer component of the sheath-core structure is a first polyethylene terephthalate, and the sheath layer component is composed of a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch;

[0044] Taking the total mass of the conductive polyester fiber as 100%, the skin component accounts for 30% and the core component accounts for 70%;

[0045] Based on the total mass of the skin layer components being 100%, the second polyethylene terephthalate accounts for 42%, the first polyamide elastomer accounts for 18%, and the conductive carbon black masterbatch accounts for 40%;

[0046] The raw materials of the conductive carbon black masterbatch are composed of a second polyamide elastomer and conductive carbon black. Calculated by weight percentage, the conductive carbon black accounts for 45% of the raw materials of the conductive carbon black masterbatch.

[0047] The first polyethylene terephthalate and the second polyethylene terephthalate were both produced by Jiangsu Guowang High-Tech Fiber Co., Ltd., and both had a number average molecular weight of 23,000 g / mol; the first polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 6060 and a number average molecular weight of 19,500 g / mol; the second polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 3050 and a number average molecular weight of 16,000 g / mol;

[0048] The conductive carbon black masterbatch was prepared by the following method: a second polyamide elastomer (grade 3050) was dried at 100°C to a moisture content of less than 50 ppm, and then pre-mixed with the conductive carbon black Vulcan® XC72R (oxidatively modified) at high speed. The mixture was then melt-blended and extruded through a twin-screw extruder, and pelletized after water cooling to obtain the conductive carbon black masterbatch. The temperatures of zones I to VII of the twin-screw extruder were 178°C, 185°C, 210°C, 210°C, 208°C, 205°C, and 200°C, respectively.

[0049] The preparation method of the conductive polyester fiber comprises:

[0050] The first polyethylene terephthalate and the second polyethylene terephthalate are dried in a low dew point drying oven at 165°C to a moisture content of less than 50 ppm; the first polyamide elastomer and the conductive carbon black masterbatch are dried in a low dew point drying oven at 120°C to a moisture content of less than 50 ppm;

[0051] The dried first polyethylene terephthalate is used as the core layer component and is melted by screw extruder I (the temperatures of zones I to IV are 285°C, 292°C, 290°C, and 290°C, respectively) and extruded by metering pump I (the temperature of the metering pump is 290°C). The dried second polyethylene terephthalate, the first polyamide elastomer, and the conductive carbon black masterbatch are used as the skin layer component and are melted by screw extruder II (the temperatures of zones I to IV are 273°C, 280°C, 278°C, and 278°C, respectively) and extruded by metering pump II (the temperature of the metering pump is 278°C). The melts of the components pass through the core-skin composite spinning assembly (the temperature of the assembly is 280°C. Under this temperature condition, the second polyethylene terephthalate is melted by screw extruder II (the temperature of the zone I to IV is 273°C, 280°C, 278°C, and 278°C, respectively). The conductive polyester fiber was extruded from polyethylene terephthalate (PET) (the zero-shear viscosity of the glycol ester was 93 Pa·s higher than that of the second polyamide elastomer, and the zero-shear viscosity of the second polyethylene terephthalate was 71 Pa·s higher than that of the first polyamide elastomer), cooled by side-blowing at 18°C ​​and a wind speed of 0.65 m / s, bundled and oiled, and then subjected to pre-stretching (the first hot roller temperature was 145°C and the speed was 800 m / min, the second hot roller temperature was 145°C and the speed was 1200 m / min), main stretching (the third hot roller temperature was 150°C and the speed was 4400 m / min), heat setting (temperature was 148°C and the speed was 4400 m / min), and finally wound at 4500 m / min to produce the conductive polyester fiber.

[0052] Example 3: This example provides a conductive polyester fiber and a preparation method thereof. The conductive polyester fiber has a sheath-core structure, wherein the core layer component of the sheath-core structure is a first polyethylene terephthalate, and the sheath layer component is composed of a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch;

[0053] Taking the total mass of the conductive polyester fiber as 100%, the skin component accounts for 40% and the core component accounts for 60%;

[0054] Based on the total mass of the skin layer components being 100%, the second polyethylene terephthalate accounts for 44%, the first polyamide elastomer accounts for 18%, and the conductive carbon black masterbatch accounts for 38%;

[0055] The raw materials of the conductive carbon black masterbatch are composed of a second polyamide elastomer and conductive carbon black. Calculated by weight percentage, the conductive carbon black accounts for 50% of the raw materials of the conductive carbon black masterbatch.

[0056] The first polyethylene terephthalate and the second polyethylene terephthalate were both produced by Jiangsu Guowang High-Tech Fiber Co., Ltd., and both had a number average molecular weight of 25,000 g / mol; the first polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 3070 and a number average molecular weight of 19,000 g / mol; the second polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 4060 and a number average molecular weight of 17,000 g / mol;

[0057] The conductive carbon black masterbatch was prepared by the following method: a second polyamide elastomer (grade 4060) was dried at 100°C to a moisture content of less than 50 ppm, and then pre-mixed with the conductive carbon black Vulcan® XC72R (oxidation-modified version) at high speed. The mixture was then melt-blended and extruded through a twin-screw extruder, and pelletized after water cooling to obtain the conductive carbon black masterbatch. The temperatures of zones I to VII of the twin-screw extruder were 178°C, 190°C, 215°C, 213°C, 213°C, 210°C, and 208°C, respectively.

[0058] The preparation method of the conductive polyester fiber comprises:

[0059] The first polyethylene terephthalate and the second polyethylene terephthalate are dried in a low dew point drying oven at 165°C to a moisture content of less than 50 ppm; the first polyamide elastomer and the conductive carbon black masterbatch are dried in a low dew point drying oven at 120°C to a moisture content of less than 50 ppm;

[0060] The dried first polyethylene terephthalate is used as the core layer component and is melted by screw extruder I (the temperatures of zones I to IV are 286°C, 294°C, 293°C, and 293°C, respectively) and extruded by metering pump I (the temperature of the metering pump is 293°C). The dried second polyethylene terephthalate, the first polyamide elastomer, and the conductive carbon black masterbatch are used as the skin layer component and are melted by screw extruder II (the temperatures of zones I to IV are 279°C, 283°C, 280°C, and 280°C, respectively) and extruded by metering pump II (the temperature of the metering pump is 280°C). The melts of the components pass through the core-skin composite spinning assembly (the temperature of the assembly is 283°C. Under this temperature condition, the second polyethylene terephthalate The zero-shear viscosity of the glycol ester is 182 Pa·s higher than that of the second polyamide elastomer, and the zero-shear viscosity of the second polyethylene terephthalate is 166 Pa·s higher than that of the first polyamide elastomer), is extruded, cooled by side-blowing at 18°C ​​and a wind speed of 0.7 m / s, and then bundled and oiled. It then passes through pre-stretching (the first hot roller temperature is 150°C and the speed is 600 m / min, the second hot roller temperature is 150°C and the speed is 800 m / min), main stretching (the third hot roller temperature is 153°C and the speed is 3600 m / min), heat setting (temperature is 153°C and the speed is 3600 m / min), and finally wound at 3650 m / min to make a conductive polyester fiber.

[0061] Example 4: This example provides a conductive polyester fiber and a preparation method thereof. The conductive polyester fiber has a sheath-core structure, wherein the core layer component of the sheath-core structure is a first polyethylene terephthalate, and the sheath layer component is composed of a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch;

[0062] Taking the total mass of the conductive polyester fiber as 100%, the skin component accounts for 45% and the core component accounts for 55%;

[0063] Based on the total mass of the skin layer components being 100%, the second polyethylene terephthalate accounts for 46%, the first polyamide elastomer accounts for 19%, and the conductive carbon black masterbatch accounts for 35%;

[0064] The raw materials of the conductive carbon black masterbatch are composed of a second polyamide elastomer and conductive carbon black. Calculated by weight percentage, the conductive carbon black accounts for 55% of the raw materials of the conductive carbon black masterbatch.

[0065] The first polyethylene terephthalate and the second polyethylene terephthalate were both produced by Jiangsu Guowang High-Tech Fiber Co., Ltd., and both had a number average molecular weight of 28,000 g / mol. The first polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 1060 and a number average molecular weight of 18,500 g / mol. The second polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 2040 and a number average molecular weight of 17,500 g / mol.

[0066] The conductive carbon black masterbatch was prepared by the following method: a second polyamide elastomer (grade 2040) was dried at 100°C to a moisture content of less than 50 ppm, and then pre-mixed with the conductive carbon black Vulcan® XC72R (oxidation-modified version) at high speed. The mixture was then melt-blended and extruded through a twin-screw extruder, and pelletized after water cooling to obtain the conductive carbon black masterbatch. The temperatures of zones I to VII of the twin-screw extruder were 178°C, 190°C, 217°C, 214°C, 214°C, 212°C, and 210°C, respectively.

[0067] The preparation method of the conductive polyester fiber comprises:

[0068] The first polyethylene terephthalate and the second polyethylene terephthalate are dried in a low dew point drying oven at 165°C to a moisture content of less than 50 ppm; the first polyamide elastomer and the conductive carbon black masterbatch are dried in a low dew point drying oven at 120°C to a moisture content of less than 50 ppm;

[0069] The dried first polyethylene terephthalate is used as the core layer component and is melted by screw extruder I (the temperatures of zones I to IV are 288°C, 296°C, 295°C, and 295°C, respectively) and extruded by metering pump I (the temperature of the metering pump is 295°C). The dried second polyethylene terephthalate, the first polyamide elastomer, and the conductive carbon black masterbatch are used as the skin layer component and are melted by screw extruder II (the temperatures of zones I to IV are 280°C, 284°C, 282°C, and 282°C, respectively) and extruded by metering pump II (the temperature of the metering pump is 282°C). The melts of the components pass through the core-skin composite spinning assembly (the temperature of the assembly is 286°C. Under this temperature condition, the second polyethylene terephthalate The zero-shear viscosity of the polyol ester is 263 Pa·s higher than that of the second polyamide elastomer, and the zero-shear viscosity of the second polyethylene terephthalate is 246 Pa·s higher than that of the first polyamide elastomer) and is extruded, cooled by side-blowing at 18°C ​​and a wind speed of 0.75 m / s, and then bundled and oiled. It then passes through pre-stretching (the first hot roller temperature is 153°C and the speed is 600 m / min, the second hot roller temperature is 153°C and the speed is 800 m / min), main stretching (the third hot roller temperature is 156°C and the speed is 4200 m / min), heat setting (temperature is 155°C and the speed is 4200 m / min), and finally wound at 4250 m / min to make a conductive polyester fiber.

[0070] Example 5: This example provides a conductive polyester fiber and a preparation method thereof. The conductive polyester fiber has a sheath-core structure, wherein the core layer component of the sheath-core structure is a first polyethylene terephthalate, and the sheath layer component is composed of a second polyethylene terephthalate, a first polyamide elastomer, and a conductive carbon black masterbatch;

[0071] Taking the total mass of the conductive polyester fiber as 100%, the skin component accounts for 50% and the core component accounts for 50%;

[0072] Based on the total mass of the skin layer components being 100%, the second polyethylene terephthalate accounts for 50%, the first polyamide elastomer accounts for 20%, and the conductive carbon black masterbatch accounts for 30%;

[0073] The raw materials of the conductive carbon black masterbatch are composed of a second polyamide elastomer and conductive carbon black. Calculated by weight percentage, the conductive carbon black accounts for 60% of the raw materials of the conductive carbon black masterbatch.

[0074] The first polyethylene terephthalate and the second polyethylene terephthalate were both produced by Jiangsu Guowang High-Tech Fiber Co., Ltd., with a number average molecular weight of 30,000 g / mol; the first polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 6050 and a number average molecular weight of 18,000 g / mol; the second polyamide elastomer was purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 4070 and a number average molecular weight of 18,000 g / mol;

[0075] The conductive carbon black masterbatch was prepared by the following method: the second polyamide elastomer (grade 4070) was dried at 100°C to a moisture content of less than 50 ppm, and then pre-mixed with the conductive carbon black Vulcan® XC72R (oxidation-modified version) at high speed. The mixture was then melt-blended and extruded through a twin-screw extruder, and pelletized after water cooling to obtain the conductive masterbatch. The temperatures of zones I to VII of the twin-screw extruder were 180°C, 192°C, 219°C, 217°C, 216°C, 214°C, and 212°C, respectively.

[0076] The preparation method of the conductive polyester fiber comprises:

[0077] The first polyethylene terephthalate and the second polyethylene terephthalate are dried in a low dew point drying oven at 165°C to a moisture content of less than 50 ppm; the first polyamide elastomer and the conductive carbon black masterbatch are dried in a low dew point drying oven at 120°C to a moisture content of less than 50 ppm;

[0078] The dried first polyethylene terephthalate is used as the core layer component and is melted by screw extruder I (the temperatures of zones I to IV are 290°C, 300°C, 298°C, and 298°C, respectively) and extruded by metering pump I (the temperature of the metering pump is 298°C). The dried second polyethylene terephthalate, the first polyamide elastomer, and the conductive carbon black masterbatch are used as the skin layer component and are melted by screw extruder II (the temperatures of zones I to IV are 282°C, 285°C, 283°C, and 283°C, respectively) and extruded by metering pump II (the temperature of the metering pump is 283°C). The melts of the components pass through the skin-core composite spinning assembly (the assembly temperature is 290°C, wherein the second polyethylene terephthalate is The zero-shear viscosity of the polyol ester is 300 Pa·s higher than that of the second polyamide elastomer, and the zero-shear viscosity of the second polyethylene terephthalate is 278 Pa·s higher than that of the first polyamide elastomer), is extruded, cooled by side-blowing at 17°C and a wind speed of 0.75 m / s, and then bundled and oiled. It then passes through pre-stretching (the first hot roller temperature is 155°C and the speed is 600 m / min, the second hot roller temperature is 155°C and the speed is 800 m / min), main stretching (the third hot roller temperature is 160°C and the speed is 4800 m / min), heat setting (temperature is 158°C and the speed is 4800 m / min), and finally wound at 4850 m / min to make a conductive polyester fiber.

[0079] Comparative Example 1: This example provides a conductive polyester elastic fiber and a preparation method thereof, which are basically the same as Example 1, with the only difference being that the cortex component is composed of a second polyethylene terephthalate and conductive carbon black, and the added mass of the conductive carbon black is the same as that in Example 1, specifically 45% × 40% = 18% of the cortex component. Accordingly, the second polyethylene terephthalate accounts for 82% of the cortex component.

[0080] Comparative Example 2: This example provides a conductive polyester elastic fiber and a preparation method thereof, which is basically the same as Example 1, with the only difference being that the carbon black used is unmodified ordinary carbon black.

[0081] Comparative Example 3: This example provides a conductive polyester elastic fiber and a preparation method thereof, which are basically the same as Example 1, with the only difference being that: η3-η1=4Pa·s, η3-η2=16Pa·s; wherein, the first polyethylene terephthalate and the second polyethylene terephthalate are both produced from Jiangsu Guowang Hi-Tech Fiber Co., Ltd., with a number average molecular weight of 13,000 g / mol; the first polyamide elastomer is purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 4050 and a number average molecular weight of 20,000 g / mol; the second polyamide elastomer is purchased from Zhejiang Xinyuan Technology Co., Ltd., with a brand name of 3060 and a number average molecular weight of 15,000 g / mol.

[0082] Performance test: The following performance test was performed on the above Examples 1-5 and Comparative Examples 1-3. The specific test results are shown in Table 1.

[0083] The test standard for fineness (dtex) is GB / T 14343-2008 "Test method for linear density of chemical fiber filaments";

[0084] The test standard for volume resistivity (Ω·cm) is FZ / T 50035-2016 “Test method for electrical resistance of synthetic filaments”;

[0085] The test standard for elongation at break (%) is GB / T 14344-2022 "Test method for tensile properties of chemical fiber filaments";

[0086] The test standard for breaking strength (cN / dtex) is GB / T 14344-2022 "Test method for tensile properties of chemical fiber filaments".

[0087]

[0088] As can be seen from Table 1, compared with Example 1, the volume resistivity of Comparative Example 1 is significantly increased (generally, the greater the volume resistivity, the worse the conductive performance), and the elongation at break is significantly decreased. Analysis shows that the carrier resin of the conductive carbon black masterbatch in Example 1 of the present invention is a polyamide elastomer, while the skin component of Comparative Example 1 is only blended with polyethylene terephthalate (PET) without the additional addition of polyamide elastomer, which hinders the migration and dispersion of the conductive carbon black in the skin layer, thereby increasing the volume resistivity of the fiber, significantly decreasing the conductive performance, and also decreasing the elongation at break.

[0089] Compared with Example 1, Comparative Example 2 used ordinary unmodified carbon black. The results showed that its volume resistivity increased. Analysis showed that this was because ordinary carbon black lacked surface carboxyl functional groups, and the interfacial interaction between it and the polyamide elastomer was significantly weakened, resulting in the polyamide elastomer being unable to effectively drive the carbon black to migrate and enrich to the fiber surface during the melt spinning process, ultimately resulting in a decrease in the conductive performance of the fiber (i.e., an increase in the volume resistivity).

[0090] Compared with Example 1, the increase in volume resistivity in Comparative Example 3 is the strongest. Analysis shows that this is because the difference in zero shear viscosity between the first polyamide elastomer and the second polyamide elastomer and the second polyethylene terephthalate (PET) is insufficient. During the melt spinning process, it is difficult for the polyamide elastomer to achieve effective surface migration, resulting in its inability to fully drive the conductive carbon black to be directional enriched in the fiber cortex, and the conductivity of the fiber decreases (i.e., the volume resistivity increases).

[0091] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0092] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. A conductive polyester fiber, characterized in that: The conductive polyester fiber has a sheath-core structure, wherein the core layer component of the sheath-core structure comprises a first polyethylene terephthalate, the sheath layer component comprises a second polyethylene terephthalate, a first polyamide elastomer and a conductive carbon black masterbatch, the raw materials of the conductive carbon black masterbatch comprise a second polyamide elastomer and conductive carbon black, the conductive carbon black has a terminal carboxyl group, and the first polyamide elastomer and the second polyamide elastomer are respectively polyether polyamide elastomers; Under the same test temperature conditions, the zero shear viscosity of the first polyamide elastomer is recorded as η1, the zero shear viscosity of the second polyamide elastomer is recorded as η2, the zero shear viscosity of the first polyethylene terephthalate and the zero shear viscosity of the second polyethylene terephthalate are both recorded as η3, and the zero shear viscosity is measured by a steady-state shear rheology experiment in units of Pa·s; when the test temperature is 275-290°C, η1, η2 and η3 satisfy the following conditions: 35Pa·s≤η3-η1≤280Pa·s, 50Pa·s≤η3-η2≤300Pa·s.

2. The conductive polyester fiber according to claim 1, characterized in that Under the same test temperature conditions, the zero shear viscosity of the first polyamide elastomer is greater than or equal to the zero shear viscosity of the second polyamide elastomer.

3. The conductive polyester fiber according to claim 1 or 2, characterized in that The number average molecular weight of the first polyamide elastomer is 18,000-20,000 g / mol; and / or the number average molecular weight of the second polyamide elastomer is 15,000-18,000 g / mol.

4. The conductive polyester fiber according to claim 1, characterized in that Under the same test temperature conditions, the zero shear viscosity of the first polyethylene terephthalate is the same as the zero shear viscosity of the second polyethylene terephthalate.

5. The conductive polyester fiber according to claim 1 or 4, characterized in that The number average molecular weight of the first polyethylene terephthalate and the number average molecular weight of the second polyethylene terephthalate are respectively 20,000-30,000 g / mol.

6. The conductive polyester fiber according to claim 1, characterized in that The polyether polyamide elastomer consists of a crystalline hard segment and a non-crystalline soft segment, the crystalline hard segment is polycaprolactam, and the non-crystalline soft segment is polyethylene glycol.

7. The conductive polyester fiber according to claim 1, characterized in that Based on 100 parts of the total amount of the skin layer components, the second polyethylene terephthalate accounts for 40-50 parts, the first polyamide elastomer accounts for 15-20 parts, and the conductive carbon black masterbatch accounts for 30-45 parts.

8. The conductive polyester fiber according to claim 1, characterized in that Based on 100 parts of the total amount of the conductive polyester fiber, the skin layer component accounts for 20-50 parts, and the core layer component accounts for 50-80 parts.

9. The conductive polyester fiber according to claim 1, characterized in that The conductive carbon black masterbatch is made by mixing and extruding a second polyamide elastomer and conductive carbon black; and / or the particle size of the conductive carbon black is 30-200 nm; and / or, in terms of mass percentage, the conductive carbon black accounts for 40%-60% of the raw materials of the conductive carbon black masterbatch.

10. The conductive polyester fiber according to claim 1, characterized in that The volume specific resistance of the conductive polyester fiber is 30~10 4 Ω·cm, fineness is 1~10dtex, breaking strength is greater than 3.5cN / dtex, and breaking elongation is 15%~35%.

11. A method for preparing the conductive polyester fiber according to any one of claims 1 to 10, characterized in that: The preparation method comprises: using a melt spinning process to spin a core layer component and a skin layer component into a conductive polyester fiber with a skin-core structure, wherein the process parameters of the spinning process include: a melt extrusion temperature of the core layer component of 285-300°C, a melt extrusion temperature of the skin layer component of 270-285°C, a spinning assembly temperature of 275-290°C, a hot drawing temperature of 140-160°C, and a hot drawing ratio of 5-8 times.

12. Use of the conductive polyester fiber according to any one of claims 1 to 10 in preparing safety protection materials, camouflage reconnaissance materials, energy harvesting materials, and smart wearable materials.

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