Graphene chinlon superfine fiber production process

Abstract

The invention relates to the related technical field of superfine fiber production, and discloses a graphene chinlon superfine fiber production process, which comprises a raw material pretreatment system, a composite spinning system and a fiber post-treatment system, the raw material pretreatment system is formed by sequentially connecting an ultrasonic treatment tank, a high-speed shearing emulsifying machine and a vacuum defoaming tank in series. Through the arrangement of the raw material pretreatment system, spiral diversion and a multi-frequency ultrasonic field can be coupled, the problem of graphene dispersion is solved, and through the arrangement of the gradient temperature control double screws, an asymmetric temperature curve can be achieved to realize the coordination of interface modification and orientation regulation and control; the conical spinneret orifice structure is added to break through the superfine fiber diameter control bottleneck through the flow field design, so that the stability of the fiber production process is improved, and the quality of a produced finished product is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field related to ultrafine fiber production, and in particular to a production process of graphene nylon ultrafine fibers. Background Art

[0002] Graphene nylon ultrafine fiber is made from a single layer of graphene oxide. Through the systematic control of polymerization parameters and processes, it is ensured that graphene can still be dispersed in a single layer in the composite fiber. It has good resilience, light weight, low fabric density, good dyeability, and heat setting properties, and can maintain the bending deformation formed when heated.

[0003] Most of the existing graphene nylon ultrafine fiber production processes suffer from uneven dispersion in the matrix, resulting in conductivity fluctuations, which in turn affects the performance of the entire fiber. In traditional graphene addition processes, graphene is prone to agglomeration, and the fiber diameter is difficult to stably control below the micron level during the spinning process, resulting in poor performance of the entire production process. In order to solve these problems, a graphene nylon ultrafine fiber production process is proposed. Summary of the Invention

[0004] The present invention provides a production process for graphene nylon ultrafine fibers, which solves the problems in the above-mentioned background technology.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A graphene nylon ultrafine fiber production process, including a raw material pretreatment system, a composite spinning system, and a fiber post-processing system;

[0007] The raw material pretreatment system is composed of an ultrasonic treatment tank, a high-speed shear emulsifier, and a vacuum degassing tank connected in series. The inner wall of the ultrasonic treatment tank is provided with a spiral guide plate, and the bottom of the tank is provided with a frequency-adjustable piezoelectric ceramic array. The high-speed shear emulsifier is equipped with double-layer turbine blades, with the upper blades having an inclination angle of 45° and the lower blades having an inclination angle of 60°.

[0008] The composite spinning system includes a twin-screw dynamic mixer, a melt spinning assembly and an annular air quenching device. The twin-screw dynamic mixer is divided into 6 independent temperature control zones along the axial direction. The temperature of the temperature zones is as follows according to the material flow direction:

[0009] First temperature zone: 240±2℃ (initial infiltration of graphene and nylon slices)

[0010] Second temperature zone: 260±2℃ (nylon melting section)

[0011] The third temperature zone: 255±2℃ (graphene dispersion and strengthening section)

[0012] The fourth temperature zone: 250±2℃ (dynamic shear mixing section)

[0013] Fifth temperature zone: 245±2℃ (melt homogenization zone)

[0014] The sixth temperature zone: 240±2℃ (outlet pressure stabilization section)

[0015] The spinneret of the melt spinning assembly adopts a honeycomb micropore array, and a single micropore is a tapered structure;

[0016] The fiber post-processing system comprises a two-stage drafting unit, a heat setting roller group and a winder. The drafting roller surface of the first-stage drafting unit is provided with a nano-ceramic coating, and the second-stage drafting unit adopts a differential roller structure.

[0017] The microfiber production process includes the following steps:

[0018] S1: The graphene dispersion was ultrasonically treated in a tank at a frequency of 40-80 kHz and a power density of 5 W / cm 3 Process for 20 to 40 minutes;

[0019] S2: The dispersion is processed in a high-speed shear emulsifier at 10,000-15,000 rpm for 10-20 min to form a stable suspension with a D90 of ≤300 nm;

[0020] S3: After degassing in a vacuum degassing tank at -0.08 to -0.1 MPa, the pellets are fed together with the dried nylon chips into a twin-screw dynamic mixer;

[0021] S4: After the melt is extruded through the spinneret, it is quenched by an annular air flow of 2-4 m / s to form nascent fibers;

[0022] S5: The spun fibers are sequentially drawn in two stages (total draw ratio 3.5-4.2) and heat-set at 160-180°C;

[0023] S6: The fiber surface is coated with a finishing agent containing γ-aminopropyltriethoxysilane.

[0024] Preferably, the temperatures of the six temperature control zones of the twin-screw dynamic mixer are 240°C → 260°C → 255°C → 250°C → 245°C → 240°C in sequence.

[0025] Preferably, the spinneret aperture is 0.08-0.15 mm, and the hole density is ≥4000 holes / m 2 , the channel length-to-diameter ratio is 10:1~15:1.

[0026] Preferably, the drawing unit comprises two-stage drawing with a total drawing ratio of 3.5 to 4.2, wherein the first-stage drawing temperature is 70 to 90°C and the second-stage drawing temperature is 95 to 110°C.

[0027] Preferably, the thickness of the graphene oxide sheets in the graphene dispersion is ≤5 nm, the dispersion concentration is 0.5-1.5 wt%, and the particle size distribution D90 is ≤300 nm.

[0028] Preferably, the surface finishing agent comprises a silane coupling agent (1-3 wt%) and a polyether-modified silicone oil (0.5-1.5 wt%).

[0029] Preferably, the quenching device adopts ring-blown air cooling with a wind speed of 2 to 4 m / s and a wind temperature of 18 to 25°C.

[0030] Preferably, the final fiber monofilament diameter is 0.3-0.5 μm, the breaking strength is ≥5.2 cN / dtex, and the conductivity is 10 -3 ~10 -5 S / cm.

[0031] The advantages and positive effects of the present invention are: through the setting of the raw material pretreatment system, the coupling spiral guide and the multi-frequency ultrasonic field can be used to solve the problem of graphene dispersion, and through the setting of the gradient temperature-controlled twin-screw, an asymmetric temperature curve can be achieved to realize the coordination of interface modification and orientation regulation. In addition, the addition of the conical spinneret structure breaks through the bottleneck of ultrafine fiber diameter control through flow field design, thereby improving the stability of the fiber production process and ensuring the quality of the finished product. DETAILED DESCRIPTION

[0032] The present invention will now be described in further detail.

[0033] Graphene nylon ultrafine fiber is made from a single layer of graphene oxide. Through the systematic regulation of polymerization parameters and processes, it is ensured that graphene can still be dispersed in a single layer in the composite fiber. It has good resilience, light weight, low fabric density, good dyeability, and heat setting properties, and can maintain the bending deformation formed when heated. Most of the existing graphene nylon ultrafine fiber production processes have uneven dispersion in the matrix, resulting in fluctuations in conductivity, thereby affecting the performance of the entire fiber. In the traditional graphene addition process, graphene is easy to agglomerate, and the fiber diameter is difficult to stably control below the micron level during the spinning process, resulting in poor effect of the entire production process. In order to solve this problem, a graphene nylon ultrafine fiber production process is proposed, including a raw material pretreatment system, a composite spinning system, and a fiber post-processing system.

[0034] The raw material pretreatment system is composed of an ultrasonic treatment tank, a high-speed shear emulsifier, and a vacuum degassing tank connected in series. The inner wall of the ultrasonic treatment tank is provided with a spiral guide plate, and the bottom of the tank is provided with a frequency-adjustable piezoelectric ceramic array. The high-speed shear emulsifier is equipped with double-layer turbine blades, with the upper blades having an inclination angle of 45° and the lower blades having an inclination angle of 60°.

[0035] The composite spinning system includes a twin-screw dynamic mixer, a melt spinning assembly and an annular air quenching device. The twin-screw dynamic mixer is divided into 6 independent temperature control zones along the axial direction. The temperature of the temperature zones is as follows according to the material flow direction:

[0036] First temperature zone: 240±2℃ (initial infiltration of graphene and nylon slices)

[0037] Second temperature zone: 260±2℃ (nylon melting section)

[0038] The third temperature zone: 255±2℃ (graphene dispersion and strengthening section)

[0039] The fourth temperature zone: 250±2℃ (dynamic shear mixing section)

[0040] Fifth temperature zone: 245±2℃ (melt homogenization zone)

[0041] The sixth temperature zone: 240±2℃ (outlet pressure stabilization section)

[0042] The spinneret of the melt spinning assembly adopts a honeycomb micropore array, and a single micropore is a tapered structure;

[0043] The fiber post-processing system comprises a two-stage drafting unit, a heat setting roller group and a winder. The drafting roller surface of the first-stage drafting unit is provided with a nano-ceramic coating, and the second-stage drafting unit adopts a differential roller structure.

[0044] The microfiber production process includes the following steps:

[0045] S1: The graphene dispersion was ultrasonically treated in a tank at a frequency of 40-80 kHz and a power density of 5 W / cm 3 Process for 20 to 40 minutes;

[0046] S2: The dispersion is processed in a high-speed shear emulsifier at 10,000-15,000 rpm for 10-20 min to form a stable suspension with a D90 of ≤300 nm;

[0047] S3: After degassing in a vacuum degassing tank at -0.08 to -0.1 MPa, the pellets are fed together with the dried nylon chips into a twin-screw dynamic mixer;

[0048] S4: After the melt is extruded through the spinneret, it is quenched by an annular air flow of 2-4 m / s to form nascent fibers;

[0049] S5: The spun fibers are sequentially drawn in two stages (total draw ratio 3.5-4.2) and heat-set at 160-180°C;

[0050] S6: The fiber surface is coated with a finishing agent containing γ-aminopropyltriethoxysilane. The raw material pretreatment system couples spiral flow guidance with a multi-frequency ultrasonic field to address graphene dispersion issues. A gradient temperature-controlled twin-screw configuration achieves an asymmetric temperature profile, synergizing interface modification and orientation control. Furthermore, the addition of a tapered spinneret structure overcomes the bottleneck of ultrafine fiber diameter control through flow field design, improving the stability of the fiber production process and ensuring the quality of the finished product.

[0051] It should be noted that the spiral guide plate enables the fluid to form a spiral ascending path, prolonging the residence time of graphene in the ultrasonic field by more than 30%, thereby ensuring the purpose of dispersion uniformity.

[0052] In addition, the 45° inclination angle of the upper blades produces radial flow, and the 60° inclination angle of the lower blades forms axial vortexes, which combine to form a three-dimensional turbulent field, thereby controlling the average particle size of graphene, which can be reduced from the traditional 500nm to 200nm, thereby enhancing its stability.

[0053] It should also be noted that the gradient temperature control setting of the twin-screw dynamic mixer is allocated through the temperature zone function: the second temperature zone is 260°C: the nylon chips are completely melted (melt index MFI = 12g / 10min), forming a low-viscosity matrix; the third temperature zone is 255°C: the hydroxyl groups on the graphene surface and the nylon amide groups form a hydrogen bond network (the FTIR detection binding peak intensity is increased by 3 times), thereby achieving the goal of increasing the fiber interface shear strength from 18MPa to 32MPa, achieving an improvement in the interface bonding force; in addition, the conductivity stability is also improved.

[0054] Furthermore, the conical microporous structure of the spinneret is simulated in detail: the flow velocity from the inlet to the outlet increases from 0.8m / s to 2.5m / s, and the stretching rate reaches 10 4 s -1 ; The degree of graphene orientation along the fiber axis (Hermans coefficient) is increased from 0.65 to 0.88, thereby achieving the purpose of meeting the fiber fineness, and also improving the limiting mechanical properties and fracture strength.

[0055] In addition, the flow field of the annular air quenching device is structurally designed to optimize the design: a guide grid (spacing 5mm) is installed in the annular air duct, and the radial gradient distribution of wind speed (2m / s at the center → 4m / s at the edge) is achieved, which reduces the fiber crystallinity from 38% to 28%, and increases the flexibility (elongation at break) to 45%. The fiber surface roughness Ra ≤ 0.1μm (traditional process ≥ 0.3μm), ensuring its surface smoothness.

[0056] It is worth mentioning that the specific distribution structure of the fiber post-processing system: through the coordinated setting of the two-stage drawing unit and the heat-setting roller group, the purpose of improving the anti-fracture performance of the limit and reducing the boiling water shrinkage rate of the fiber can be achieved, thereby ensuring its dimensional stability.

[0057] In addition, the durability and antibacterial properties of the fiber can be improved by adding surface finishing agents.

[0058] The structure in the above embodiment enables the comprehensive performance of the fiber to be improved in a relatively stable manner. The specific improvement data are shown in the following table.

[0059]

[0060] Table 1: Comprehensive performance comparison

[0061] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the embodiments described in the specific implementation methods. Any other implementation methods derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A process for producing graphene nylon ultrafine fibers, characterized by: Including raw material pretreatment system, composite spinning system, and fiber post-processing system; The raw material pretreatment system is composed of an ultrasonic treatment tank, a high-speed shear emulsifier, and a vacuum degassing tank connected in series. The inner wall of the ultrasonic treatment tank is provided with a spiral guide plate, and the bottom of the tank is provided with a frequency-adjustable piezoelectric ceramic array. The high-speed shear emulsifier is equipped with double-layer turbine blades, with the upper blades having an inclination angle of 45° and the lower blades having an inclination angle of 60°. The composite spinning system includes a twin-screw dynamic mixer, a melt spinning assembly and an annular air quenching device. The twin-screw dynamic mixer is divided into 6 independent temperature control zones along the axial direction. The temperature of the temperature zones is as follows according to the material flow direction: First temperature zone: 240±2℃ (initial infiltration of graphene and nylon slices) Second temperature zone: 260±2℃ (nylon melting section) The third temperature zone: 255±2℃ (graphene dispersion and strengthening section) The fourth temperature zone: 250±2℃ (dynamic shear mixing section) Fifth temperature zone: 245±2℃ (melt homogenization zone) The sixth temperature zone: 240±2℃ (outlet pressure stabilization section) The spinneret of the melt spinning assembly adopts a honeycomb micropore array, and a single micropore is a tapered structure; The fiber post-processing system comprises a two-stage drafting unit, a heat setting roller group and a winder. The drafting roller surface of the first-stage drafting unit is provided with a nano-ceramic coating, and the second-stage drafting unit adopts a differential roller structure. Microfiber production process The following steps are involved: S1: The graphene dispersion was ultrasonically treated in a tank at a frequency of 40-80 kHz and a power density of 5 W / cm 3 Process for 20 to 40 minutes; S2: The dispersion is processed in a high-speed shear emulsifier at 10,000-15,000 rpm for 10-20 min to form a stable suspension with a D90 of ≤300 nm; S3: After degassing in a vacuum degassing tank at -0.08 to -0.1 MPa, the pellets are fed together with the dried nylon chips into a twin-screw dynamic mixer; S4: After the melt is extruded through the spinneret, it is quenched by an annular air flow of 2-4 m / s to form nascent fibers; S5: The spun fibers are sequentially drawn in two stages (total draw ratio 3.5-4.2) and heat-set at 160-180°C; S6: The fiber surface is coated with a finishing agent containing γ-aminopropyltriethoxysilane.

2. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The temperatures of the six temperature control zones of the twin-screw dynamic mixer are 240°C → 260°C → 255°C → 250°C → 245°C → 240°C in sequence.

3. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The spinneret aperture is 0.08-0.15 mm, and the hole density is ≥4000 holes / m 2 , the channel length-to-diameter ratio is 10:1~15:

1.

4. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The drawing unit comprises two-stage drawing with a total drawing ratio of 3.5 to 4.2, wherein the first-stage drawing temperature is 70 to 90° C. and the second-stage drawing temperature is 95 to 110° C.

5. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The graphene oxide sheet thickness in the graphene dispersion is ≤5nm, the dispersion concentration is 0.5-1.5wt%, and the particle size distribution D90 is ≤300nm.

6. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The surface finishing agent comprises a silane coupling agent (1-3 wt%) and a polyether modified silicone oil (0.5-1.5 wt%).

7. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The quenching device adopts annular air cooling with a wind speed of 2 to 4 m / s and a wind temperature of 18 to 25°C.

8. The process for producing graphene nylon ultrafine fibers according to claim 1, wherein: The final fiber monofilament diameter is 0.3~0.5μm, the breaking strength is ≥5.2cN / dtex, and the conductivity is 10 -3 ~10 -5 S / cm.

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