Preparation method of graphene composite polyester fiber

Abstract

The invention discloses a preparation method of a graphene composite polyester fiber, which comprises the following steps: (1) preparation of a low-melting-point graphene master batch: mixing high-alkene single-layer graphene oxide powder, 180 DEG C low-melting-point PET powder and zinc stearate, and then performing extrusion processing and granulation through vacuum twin-screw extrusion to obtain the low-melting-point graphene master batch; (2) spinning by adopting a double-component sheath-core type composite spinning assembly to obtain graphene composite polyester fibers; wherein the two components comprise a component A and a component B; graphene is added in the form of master batch, direct contact between graphene powder and equipment is avoided, drifting and attachment of graphene in the equipment are effectively reduced, the risk of equipment pollution is reduced, and the prepared graphene composite polyester fiber has a good antibacterial effect.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester fibers, and particularly relates to a method for preparing graphene composite polyester fibers. Background Art

[0002] CN 103710790 A discloses an antistatic, antibacterial, graphene-reinforced composite polyester fiber, which is composed of component A and component B. Component A is polyester without graphene, and component B is polyester containing 0.3-3.0% graphene by weight. The preparation method thereof is as follows:

[0003] A. Preparation of graphene-containing polyester as B component:

[0004] 1. Mix graphene powder with ethylene glycol liquid, add dispersant and coupling agent, and stir and grind.

[0005] 2. The solution obtained in step 1 is subjected to ultrasonic dispersion treatment to obtain a graphene / ethylene glycol solution in which graphene is evenly dispersed.

[0006] 3. Add purified terephthalic acid to the graphene / ethylene glycol solution obtained in step 2, mix evenly, then add the polyester catalyst and stir evenly to form a slurry.

[0007] 4. According to the polyester production process, the above slurry is subjected to esterification polymerization reaction to generate polyester melt, which is then cooled and granulated to prepare component B.

[0008] B. Composite spinning process:

[0009] Polyester without graphene is used as component A. Components A and B are crystallized and dried respectively, and then a composite spinning process is adopted to form composite polyester fibers with a parallel structure, a skin-core structure or an eccentric core structure.

[0010] The composite polyester fiber prepared by this technical solution has the advantages of low cost, high strength, good antistatic and antibacterial properties, etc. The preparation method is to add graphene material during the polymerization process so that the graphene is evenly dispersed in the polyester matrix material, thereby ensuring the spinnability of the fiber.

[0011] However, although this technical solution has shown significant advantages in many aspects, there are also some serious problems that cannot be ignored. The particle size range of the graphene powder used is 500-2000nm. The graphene powder in this particle size range has the characteristics of light powder, flocculent form and black color. When it is added to the reaction system during the polymerization reaction stage, it will cause a series of problems, resulting in pollution of related equipment and a significant increase in energy costs. Specifically, it is manifested in the following aspects:

[0012] 1. In the critical link of esterification reaction, due to the complexity and fluidity of the reaction system, a small amount of graphene powder will enter the esterification tower and its affiliated pipes with the flow of esterification water. Once these graphene powders enter the equipment, they will adhere to the inner wall of the equipment and the surface of the pipes, forming dirt that is difficult to remove. Similarly, during the polycondensation reaction, a small amount of graphene powder will also enter the vacuum spray system with the flow of ethylene glycol vapor, further expanding the scope of pollution. Since graphene itself has unique hierarchical characteristics, there are strong interactions such as van der Waals forces between its layers, making it extremely difficult to clean the contaminated equipment in the subsequent cleaning process. Traditional cleaning methods are often difficult to completely remove them, which not only consumes a lot of time and manpower, but may also cause damage to the equipment, increasing the maintenance cost of the equipment and the risk of production interruption.

[0013] 2. If the polymerization reactor and melt pipeline are used to produce graphene-containing products during the production process, a large amount of carbon black melt will remain in the equipment and pipelines. Because this melt contains graphene components, its viscosity and fluidity and other properties are quite different from those of traditional polyester melts, which makes it a huge challenge to clean it up after production. The residual carbon black melt is difficult to remove by conventional cleaning methods, and often adheres firmly to the inner walls of the equipment and pipelines, forming a layer of stubborn stains that are difficult to remove. This will not only affect the normal operation and production efficiency of the equipment, but also cause serious obstacles to the subsequent conversion to produce other products, because the residual graphene components may have an adverse effect on the performance and quality of other products, resulting in unstable product quality and failure to meet the production requirements of different products, thereby limiting the flexibility and versatility of production equipment and increasing the production costs and market risks of enterprises.

[0014] 3. During the polycondensation reaction, in order to achieve material recycling and energy conservation and emission reduction, a certain amount of crude ethylene glycol will be collected. However, due to the addition of graphene powder during the reaction, the collected crude ethylene glycol contains a very small amount of graphene powder. The presence of these graphene powders changes the properties of crude ethylene glycol, and it cannot be directly distilled and reused like conventional crude ethylene glycol. During the distillation process, graphene powder may form blockages in the distillation equipment, affecting the distillation effect and even causing equipment failure. Even after some special treatment methods, such as filtration and adsorption, trying to remove the graphene powder, due to the certain interaction between graphene and ethylene glycol, and the small particle size of graphene powder, easy to disperse again, the treated crude ethylene glycol still cannot meet the quality standards of conventional recycled ethylene glycol, and cannot be directly used for secondary production like conventional recycled ethylene glycol. This not only increases the waste of materials in the production process, but also increases the production cost, and also brings certain challenges to the sustainable development of enterprises. Summary of the invention

[0015] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing graphene composite polyester fiber.

[0016] The technical solution of the present invention is as follows:

[0017] A method for preparing a graphene composite polyester fiber comprises the following steps:

[0018] (1) Preparation of low-melting-point graphene masterbatch: high-glycin monolayer graphene oxide powder, 180°C low-melting-point PET powder and zinc stearate are mixed and kneaded, and then extruded and granulated by vacuum twin-screw extrusion to obtain low-melting-point graphene masterbatch;

[0019] (2) Spinning with a two-component core-skin composite spinning assembly to obtain graphene composite polyester fiber; wherein the component is composed of component A and component B,

[0020] Component A is a crystallized and dried antimony-free semi-dull polyester chip, the water content of which is controlled below 25 ppm. Component A is melt-extruded through a single screw and passed through a core layer channel;

[0021] Component B is prepared by mixing 180°C low-melting point polyester pellets with the low-melting point graphene masterbatch obtained in step (1) through a syringe, and then directly entering a vacuum twin-screw extruder for melt extrusion without drying, and then passing through a cortical channel.

[0022] In a preferred embodiment of the present invention, the mass ratio of the 180°C low-melting point polyester pellets to the low-melting point graphene masterbatch obtained in step (1) is 95:5.

[0023] In a preferred embodiment of the present invention, the step (1) comprises:

[0024] A. Stir and mix the high-glycin monolayer graphene oxide powder, 180°C low melting point PET powder and zinc stearate at a speed of 500-600 rpm for 4-6 minutes to obtain a uniformly mixed material;

[0025] B. The above materials are fed into a vacuum twin-screw extruder, and after extrusion processing and granulation steps, low-melting-point graphene masterbatch for spinning is obtained.

[0026] Further preferably, in step A of step (1), the mass ratio of the high-olefin single-layer graphene oxide powder, the 180°C low-melting-point PET powder and zinc stearate is 2-5:94.9-97.9:0.1.

[0027] More preferably, in step B of step (1), the aspect ratio of the screw of the vacuum twin-screw extruder is 40:1, the screw processing temperature is controlled at 180-195°C, and the screw speed is 400-500rpm.

[0028] In a preferred embodiment of the present invention, the step (2) comprises:

[0029] A. The component A and the component B are respectively introduced into the core-skin composite spinning assembly through their respective melt pipes;

[0030] B. Under the precise metering and pressurization of the metering pump, component A and component B are extruded at the spinneret hole at a mass ratio of 70:30;

[0031] C. The extruded filaments are sequentially subjected to the steps of annular air cooling, oiling, drawing and winding to finally obtain FDY fully drawn filaments, i.e. the graphene composite polyester fibers.

[0032] Further preferably, in step B of step (2), the mass ratio of component A to component B is 65-75:25-35.

[0033] More preferably, in step (2), the spinning box temperatures corresponding to component A and component B are 278° C. and 230° C. respectively.

[0034] Still further preferably, in the step (2), the spinning speed is set to 4700-4800 m / min.

[0035] The beneficial effects of the present invention are:

[0036] 1. The present invention fully mixes graphene powder with low-melting-point PET powder and zinc stearate, and performs high-temperature melt extrusion and granulation in a vacuum twin-screw extruder, so that the graphene is uniformly wrapped and dispersed in the low-melting-point PET matrix; in this way, in the subsequent spinning process, the graphene is added in the form of a masterbatch, which avoids direct contact between the graphene powder and the equipment, thereby effectively reducing the scattering and adhesion of the graphene in the equipment and reducing the risk of equipment pollution.

[0037] 2. When preparing low-melting-point graphene masterbatch in the present invention, the selected 180°C low-melting-point PET powder can be evenly mixed with graphene and the like at a relatively low temperature (180-195°C) and complete the extrusion granulation process; in the subsequent spinning process, the low-melting-point graphene masterbatch can also be melted at a lower temperature and composite-spun with the low-melting-point polyester pellets, thereby reducing energy consumption and energy costs in the entire production process.

[0038] 3. The present invention adopts a two-component core-skin composite spinning assembly, component A is an antimony-free semi-dull polyester chip that does not contain graphene, and runs through the core layer channel; component B is a mixture of low-melting point polyester pellets and low-melting point graphene masterbatch, and runs through the cortex channel; the design of this core-skin structure makes the graphene mainly distributed in the cortex part of the fiber, while the core layer does not contain graphene; during the spinning process, the graphene is confined to a specific area of ​​the cortex and will not diffuse freely in the entire equipment and pipeline as in the preparation method of the prior art, thereby reducing the scope of graphene pollution to the equipment; at the same time, because the graphene is wrapped in a low-melting point polyester matrix, its adhesion in the equipment is relatively weakened, and when cleaning the equipment, the cortex part containing graphene is more easily peeled off and removed, reducing the difficulty of cleaning the equipment.

[0039] 4. The present invention adopts a skin-core composite spinning process, so that when it is necessary to switch production, only the equipment and pipelines of the skin part need to be cleaned. Since the core part does not contain graphene, its residual melt is relatively easy to handle; and since the melting point of the low-melting-point graphene masterbatch is relatively low, during the cleaning process, the temperature can be appropriately increased to make it easier to melt and discharge from the equipment, thereby greatly shortening the cleaning time of the production switch, improving the flexibility of the production equipment, and being able to better adapt to the diversified market needs.

[0040] 5. The structural design of the graphene composite polyester fiber prepared in the present invention adopts a core layer and a skin layer separated structure; the core layer of the fiber is made of ordinary semi-matt slices, which are in sufficient supply and relatively stable in price in the market, providing a reliable guarantee for the basic performance of the fiber; at the same time, the graphene is only accurately dispersed in the skin layer of the fiber, so that the amount of graphene is greatly reduced, avoiding the substantial increase in cost caused by the use of graphene in the entire fiber range. In this way, the product of the present invention not only successfully obtains the unique functions given by graphene, but also significantly reduces the cost of using graphene in the production process, thereby achieving effective control of production costs while ensuring the high performance of the product.

[0041] 6. The graphene composite polyester fiber preparation method of the present invention has made innovations in process design, completely avoiding the generation and recovery of crude ethylene glycol; this improvement not only fundamentally solves the environmental burden caused by the treatment of crude ethylene glycol in the traditional polyester fiber production process, but also significantly reduces the energy consumption and cost investment in the production process. By optimizing the process flow, the present invention improves production efficiency while reducing the negative impact on the environment, achieving a win-win situation of economic and environmental benefits.

[0042] 7. The graphene composite polyester fiber prepared by the present invention has excellent antibacterial properties and can effectively inhibit the growth of many common pathogenic bacteria. Moreover, since it does not contain any metal components, it has excellent safety. The inhibition rate against Staphylococcus aureus reaches 89-99%, the inhibition rate against Candida albicans reaches 83-94%, and the inhibition rate against Escherichia coli reaches 88-99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a diagram showing the antibacterial effect of the graphene composite polyester fiber prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further illustrated and described below through specific implementation modes in combination with the accompanying drawings.

[0045] Example 1

[0046] (1) Preparation of low melting point graphene masterbatch:

[0047] A. 2 parts by weight of high-gold monolayer graphene oxide powder (purchased from Hangzhou Gaoxi Technology Co., Ltd., https: / / www.gaoxitech.com / special1.html), 97.9 parts by weight of 180°C low-melting-point PET powder (ground into powder from 180°C low-melting-point polyester pellets, the preparation of the 180°C low-melting-point polyester pellets is carried out with reference to CN 102585185 B, and the melting point reaches 180°C and the intrinsic viscosity is 0.75 dL / g by adjusting the distribution ratio of each component, especially reducing the amount of diethylene glycol and ethylene glycol) and 0.1 parts by weight of zinc stearate are put into a high-speed mixer, and fully stirred and mixed at a speed of 550 rpm for 5 minutes to obtain a uniformly mixed material;

[0048] B. feeding the above materials into a vacuum twin-screw extruder, wherein the aspect ratio of the screw of the vacuum twin-screw extruder is 40:1, the screw processing temperature is controlled at 180-195° C., and the screw speed is 450 rpm; after the above materials undergo extrusion processing and granulation steps in the extruder, a low-melting-point graphene masterbatch for spinning is obtained;

[0049] The low melting point graphene masterbatch has a particle size of 2.3 mm, a length of 3 mm, an intrinsic viscosity of 0.55 dL / g, and a melting point of 180°C;

[0050] (2) Spinning: Spinning is carried out using a two-component sheath-core composite spinning assembly, wherein:

[0051] Component A is a crystallized and dried antimony-free semi-dull polyester chip, the water content of which is controlled below 25 ppm. Component A is melt-extruded through a single screw and passed through a core layer channel;

[0052] Component B is a mixture of 180°C low-melting point polyester pellets (same as above) and the low-melting point graphene masterbatch obtained in step (1) in a ratio of 95:5. The mixture is mixed by a syringe and directly fed into a vacuum twin-screw extruder for melt extrusion without drying, and then passes through a cortex channel.

[0053] Specifically include:

[0054] A. The above-mentioned component A and component B are respectively introduced into the core-skin composite spinning assembly through their respective melt pipes;

[0055] B. Under the precise metering and pressurization of the metering pump, component A and component B are extruded at the spinneret hole at a mass ratio of 70:30;

[0056] C. The extruded filaments are successively subjected to the steps of annular air cooling, oiling, drawing and winding to finally obtain FDY fully drawn filaments, i.e., the graphene composite polyester fibers, having a specification of 55dtex / 24f, a breaking strength of 4.21cN / dtex, and an elongation at break of 40.1%. In the above spinning process, the temperatures of the spinning box corresponding to component A and component B are 278°C and 230°C, respectively, and the spinning speed is set to 4750m / min.

[0057] The antibacterial effect of the graphene composite polyester fiber prepared in this embodiment is as follows: the inhibition rate of Staphylococcus aureus, the inhibition rate of Candida albicans, and the inhibition rate of Escherichia coli are 89%, 83%, and 88% respectively, and no metal dissolution is detected in the sanitary safety immersion test according to GB / T 5750.6-2023 Standard Test Methods for Drinking Water Part 6: Metal and Metalloid Indicators.

[0058] Example 2

[0059] The method is basically the same as Example 1, except that: in step A of step (1), 5 parts by weight of high-olefin single-layer graphene oxide powder (purchased from Hangzhou High-olefin Technology Co., Ltd.), 94.9 parts by weight of 180°C low-melting-point PET powder (same as Example 1) and 0.1 parts by weight of zinc stearate are put into a high-speed mixer. The graphene composite polyester fiber prepared in this example has a specification of 55 dtex / 24f, a breaking strength of 4.18 cN / dtex, an elongation at break of 40.3%, and an antibacterial effect of Figure 1 As shown, according to GB / T 5750.6-2023 Standard Test Methods for Drinking Water Part 6: Metal and Metalloid Indicators, a sanitary safety immersion test was carried out and no metal dissolution was detected.

[0060] Example 3

[0061] It is basically the same as Example 1, except that: component A and component B are co-extruded at the spinneret hole at a mass ratio of 75:25. The specification of the graphene composite polyester fiber prepared in this example is 55dtex / 24f, the breaking strength is 4.61cN / dtex, the breaking elongation is 39.7%, and the antibacterial rate is the same as that in Example 1. At the same time, according to GB / T 5750.6-2023 Standard Test Method for Drinking Water Part 6: Metal and Metalloid Index, a sanitary safety immersion test was carried out, and no metal dissolution was detected.

[0062] Example 4

[0063] It is basically the same as Example 1, except that: component A and component B are co-extruded at the spinneret hole at a mass ratio of 65:35. The specification of the graphene composite polyester fiber prepared in this example is 55dtex / 24f, the breaking strength is 3.79cN / dtex, the breaking elongation is 39.8%, and the antibacterial rate is the same as Example 1. At the same time, according to GB / T 5750.6-2023 Standard Test Method for Drinking Water Part 6: Metal and Metalloid Index, a sanitary safety immersion test was carried out, and no metal dissolution was detected.

[0064] Comparative Example 1

[0065] The method is basically the same as Example 1, except that no high-olefin single-layer graphene oxide powder is added. The specifications of the composite polyester fiber prepared in this comparative example are basically the same as those in Example 1, and it has no inhibitory effect on Staphylococcus aureus, Candida albicans and Escherichia coli.

[0066] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing graphene composite polyester fiber, characterized in that: The steps include: (1) Preparation of low-melting-point graphene masterbatch: high-glycin monolayer graphene oxide powder, 180°C low-melting-point PET powder and zinc stearate are mixed and kneaded, and then extruded and granulated by vacuum twin-screw extrusion to obtain low-melting-point graphene masterbatch; (2) Spinning with a two-component core-skin composite spinning assembly to obtain graphene composite polyester fibers; wherein the two components are composed of component A and component B, Component A is a crystallized and dried antimony-free semi-dull polyester chip, the water content of which is controlled below 25 ppm. Component A is melt-extruded through a single screw and passed through a core layer channel; Component B is prepared by mixing 180°C low-melting point polyester pellets with the low-melting point graphene masterbatch obtained in step (1) through a syringe, and then directly entering a vacuum twin-screw extruder for melt extrusion without drying, and then passing through a cortical channel.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the 180°C low-melting point polyester pellets to the low-melting point graphene masterbatch obtained in step (1) is 95:

5.

3. The preparation method according to claim 1 or 2, characterized in that: The step (1) comprises: A. Stir and mix the high-glycin monolayer graphene oxide powder, 180°C low melting point PET powder and zinc stearate at a speed of 500-600 rpm for 4-6 minutes to obtain a uniformly mixed material; B. The above materials are fed into a vacuum twin-screw extruder, and after extrusion processing and granulation steps, low-melting-point graphene masterbatch for spinning is obtained.

4. The preparation method according to claim 3, characterized in that: In step A of step (1), the mass ratio of the high-olefin single-layer graphene oxide powder, the 180° C. low-melting-point PET powder and zinc stearate is 2-5:94.9-97.9:0.

1.

5. The preparation method according to claim 4, characterized in that: In step B of step (1), the aspect ratio of the screw of the vacuum twin-screw extruder is 40:1, the screw processing temperature is controlled at 180-195° C., and the screw speed is 400-500 rpm.

6. The preparation method according to claim 1 or 2, characterized in that: The step (2) comprises: A. The component A and the component B are respectively introduced into the core-skin composite spinning assembly through their respective melt pipes; B. Under the precise metering and pressurization of the metering pump, component A and component B are extruded at the spinneret hole at a mass ratio of 70:30; C. The extruded filaments are sequentially subjected to the steps of annular air cooling, oiling, drawing and winding to finally obtain FDY fully drawn filaments, i.e. the graphene composite polyester fibers.

7. The preparation method according to claim 6, characterized in that: In step B of step (2), the mass ratio of component A to component B is 65-75:25-35.

8. The preparation method according to claim 7, characterized in that: In the step (2), the spinning box temperatures corresponding to component A and component B are 278° C. and 230° C. respectively.

9. The preparation method according to claim 8, characterized in that: In the step (2), the spinning speed is set to 4700-4800 m / min.

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