CN113769675A - Heart-shaped micro-reactor, continuous polymerization device and device for preparing modified meta-aramid fiber through continuous polymerization-dry-wet spinning - Google Patents

Abstract

The invention provides a heart-shaped micro-reactor, a continuous polymerization device and a continuous polymerization-dry-wet spinning device, wherein the heart-shaped micro-reactor comprises an upper cover plate, a base, a feeding channel, a discharging channel and a heat transfer medium channel; the feed channel and the discharge channel are connected with the micro-channel, and the micro-channel is connected with the heart-shaped micro-reaction chamber. The continuous polymerization device comprises a heart-shaped micro-reactor, the continuous polymerization-dry-wet spinning device comprises a continuous polymerization device, the continuous polymerization device is connected with a spinning system, a gas cavity is arranged at an air section between a spinneret plate and a coagulating bath of the spinning system, and an air inlet/outlet is formed in the gas cavity. The excellent heat transfer effect of the heart-shaped microreactor ensures that the temperature of the system is accurately controlled, the generation of byproducts caused by local overheating is prevented, and the low polydispersity, stability and controllability of resin molecules are ensured; the gas cavity in the spinning system can regulate and control and perfect the fiber shape and microstructure by controlling the gas temperature and flow rate, thereby improving the performance and batch stability of the fiber.

Description

Heart-shaped micro-reactor, continuous polymerization device and device for preparing modified meta-aramid fiber through continuous polymerization-dry-wet spinning

Technical Field

The invention belongs to the field of high polymer materials, relates to a manufacturing technology of resin and fiber, and particularly relates to a heart-shaped microreactor, a continuous polymerization device and a device for preparing modified meta-aramid fiber by continuous polymerization-dry-wet spinning.

Background

The aromatic polyamide has excellent performances of high modulus, high strength, high temperature resistance, insulation and the like due to the unique chemical structure, attracts a large number of domestic and foreign researchers to develop and research since the six and seventies of the last century, is one of key materials in high and new technical fields at present, and is widely applied to the advanced fields of electronics and electricity, national defense, aerospace, military, emergency rescue and the like, and the high-end civil fields of rail transit, building, high-temperature transmission, filtration, sports goods and the like. Heterocyclic rings such as imidazole, oxazole, thiazole and the like have excellent thermal stability and good polarity, and introduction of the heterocyclic rings into a polymer main chain can not only improve heat resistance and mechanical properties, but also improve solubility and processability of the polymer due to the presence of hetero atoms. The Russia originally developed heterocyclic aramid fibers such as Armos, SVM and the like, the modulus and strength of which are far higher than those of para-aramid fibers or meta-aramid fibers and even comparable with high-performance carbon fibers T800H, so that the development and research of the heterocyclic aramid fibers are generally concerned by the high-performance material field and become a great research hotspot. The research technology of heterocyclic modification of para-aramid has entered the mature period and is monopolized by foreign patents and markets, while the research of meta-aramid modification is still in the stage of sprouting development and has a larger breakthrough space.

At present, China faces the following dilemma on the meta-aramid spinning technology:

1) the meta-aramid resin prepared by the traditional kettle type batch polymerization has low molecular weight, wide molecular weight distribution, low solid content of spinning solution and the problem of batch stability;

the commonly used method for preparing the meta-aramid resin in China is low-temperature solution polymerization, and equipment is a kettle type reactor. On one hand, because the heat release speed of the meta-aramid polymerization system is high, and the kettle type reactor only exchanges heat through an external jacket, the heat of the reaction system cannot be quickly removed, the low temperature of the reaction system and the temperature uniformity of the whole reaction system cannot be ensured, so that the reaction synchronism is poor, the side reactions are more, and the molecular weight and the distribution of the polymer are difficult to control; on the other hand, the viscosity of the meta-aramid polymerization system is high, the stirring form of the kettle type polymerizer cannot enable materials to be uniformly mixed, particularly the viscosity of the polymerization system is increased in the later reaction period, the difficulty in mixing the materials is further increased, and the local monomer concentration is too high or too low, so that local implosion or too low local polymerization degree is caused, the reaction is insufficient, the obtained meta-aramid resin is low in molecular weight, wide in molecular weight distribution and poor in spinnability of a resin solution.

2) The performance of the fiber obtained by wet spinning can not meet the application requirement of high-end field

The mature commercial preparation process of the meta-aramid fiber mainly comprises wet spinning and dry spinning. The wet spinning technology has relatively low difficulty, large output of a single spinneret and low production cost, but the prepared fiber has general performance. The fiber prepared by the dry spinning method has excellent comprehensive performance, but has high technical difficulty, high requirements on process control and equipment and high production cost. Dry-wet spinning combines the characteristics of wet spinning and dry spinning, but compared with wet spinning, dry-wet spinning has higher requirements on spinning solution and process control, and needs to improve spinning solution, spinning equipment and process. The existing dry-wet spinning equipment has the defects that after being sprayed out, strands pass through a section of air layer and then enter a coagulating bath, the air layer has no additional device, and the strand forming and microstructure forming are easily influenced by the environment to generate fluctuation and even serious defects, so that the final structure and performance of fibers and the batch stability are influenced.

3) Continuous and efficient production is not realized; the problems of neutralization of meta-aramid resin solution, low filtration efficiency, spinneret plate blockage, broken filaments and filament breakage caused by inorganic salt contained in the meta-aramid resin solution, unsatisfactory performance of the obtained fiber and the like.

Disclosure of Invention

The invention aims to solve the technical problem of how to improve the whole equipment and process to prepare the modified meta-aramid fiber with complete structure and excellent performance, overcome the defects in the background technology and provide a heart-shaped microreactor, a continuous polymerization device and a device for preparing the modified meta-aramid fiber by continuous polymerization-dry-wet spinning.

The technical scheme provided by the invention is as follows:

a heart-shaped microreactor comprises an upper cover plate and a base, wherein the upper cover plate is provided with a first feeding channel, a second feeding channel and a discharging channel, and the upper cover plate and the base are provided with heat transfer medium channels for conveying heat transfer media; the first feeding channel and the second feeding channel are respectively connected with the first micro-channel and the second micro-channel, the first micro-channel and the second micro-channel are connected with the heart-shaped micro-reaction chamber after being converged, the heart-shaped micro-reaction chamber is connected with the third micro-channel, and the third micro-channel is connected with the discharging channel.

The micro-reactor has great heat exchange area and mixing efficiency, can quickly realize heat exchange, solves the problem of overhigh reaction temperature at the initial stage of pre-polycondensation, and realizes accurate control of the temperature in the pre-polycondensation process, thereby preventing the high-temperature oxidation yellowing of resin and the generation of byproducts caused by local overheating.

The heart-shaped microchannel reactor greatly improves the heat exchange area and the mixing efficiency due to the structural design of the heart-shaped microchannel, materials can be fully mixed in the tube, and local overheating is avoided, so that the molecular weight and the distribution of resin are improved, and the spinnability of spinning stock solution and the performance of obtained fibers are improved.

Due to the special structural design of the heart-shaped microreactor, materials can be fully mixed in a heart-shaped region to generate further polymerization, and then are conveyed to the rear end through a pipeline; meanwhile, partial materials can be mixed and reacted with new materials again through a side end pipeline, so that the molecular weight and the distribution of the resin are improved, and the spinnability of the spinning solution and the performances of the obtained fibers, particularly the mechanical property and the heat resistance, are improved.

Preferably, the heart-shaped micro-reaction chambers are connected in series through the micro-channels, every two heart-shaped micro-reaction chambers are arranged in an up-and-down overlapping mode to form a group of heart-shaped micro-reaction chamber units, and the heart-shaped micro-reaction chamber units are connected in series through the micro-channels.

The material mostly is quick-mixing exothermic in the microreactor, overlaps the heart shape micro-reaction channel of establishing ties from top to bottom and can utilize microreactor shell inner space to the at utmost, realizes the circulation heat transfer simultaneously, has solved the heat transfer problem, has avoided the emergence of side reaction.

Preferably, two heart-shaped micro reaction chambers in the heart-shaped micro reaction chamber unit are connected end to end through micro channels, the micro channels at the end of the feeding channel are connected with the concave part of the heart-shaped micro reaction chambers, and the micro channels at the end of the discharging channel are connected with the heart-shaped tip part of the heart-shaped micro reaction chambers.

Preferably, the heart-shaped micro reaction chamber has a hollow structure.

Circular and irregular hollow structures are added in the heart-shaped micro reaction chamber, so that convection and mixing of materials in the micro reaction chamber can be enhanced on the premise of ensuring the flow area, and heat exchange is further realized.

Under the same technical idea, the invention also provides a continuous polymerization device which mainly comprises a raw material storage device, a prepolymerization system, a polycondensation system, a post-treatment system and a heat exchange system; the pre-polymerization system, the polycondensation system and the post-treatment system are sequentially connected, and the heat exchange system is respectively connected with the pre-polymerization system and the polycondensation system to control the temperature of the pre-polymerization system and the temperature of the polycondensation system; the prepolymerization system comprises a micromixer and a microreactor which are sequentially connected, the polycondensation system comprises a multistage micro screw device, and the microreactor is connected with the multi-edge micro screw device.

Preferably, a solvent dehydration device is connected between the m-phenylenediamine and co-phenylenediamine monomer raw material storage tank and the solvent raw material storage tank containing the cosolvent, and the m-phthaloyl chloride raw material storage tank, the m-phenylenediamine and third monomer raw material storage tank are respectively connected with the micro mixer through an advection pump and a conveying pipeline.

Preferably, the raw material storage device further comprises a solvent drying system, and the solvent drying system is respectively connected with a m-phenylenediamine and third monomer raw material storage tank and a solvent raw material storage tank containing a cosolvent; and heat-insulating jackets are sleeved on the isophthaloyl dichloride raw material storage tank, the m-phenylenediamine and third monomer raw material storage tank, the advection pump and the conveying pipeline.

The heat exchange system comprises a refrigeration cycle device and a heating cycle device, wherein the refrigeration cycle device comprises a refrigeration medium storage tank filled with a cold medium, a heat exchange medium delivery pump, a rotor flow meter and a medium delivery pipeline, the heat exchange medium delivery pump and the rotor flow meter are connected between the refrigeration medium storage tank and the micro mixer, and the medium delivery pipeline connects the refrigeration medium storage tank, the micro mixer and the microreactor to form a circulation loop; the heating circulation device comprises a heating medium storage tank filled with a heating medium, a heat exchange medium delivery pump, a rotor flow meter and a medium delivery pipeline, wherein the heat exchange medium delivery pump and the rotor flow meter are connected between the heating medium storage tank and the multistage micro-screw devices, and the medium delivery pipeline connects the heating medium storage tank and the multistage micro-screw devices to form a circulation loop.

The multistage micro-screw device comprises a first-stage micro-screw device, a second-stage micro-screw device, a third-stage micro-screw device and a fourth-stage micro-screw device which are not limited to be connected in sequence, heat insulation jackets are sleeved from the first-stage micro-screw device to the fourth-stage micro-screw device, a heat medium in the heating circulation device is introduced into the heat insulation jackets, the diameters of screws from the first-stage micro-screw device to the fourth-stage micro-screw device are gradually increased, the length-diameter ratio of the screws is gradually reduced, the rotating speed of the screws is gradually increased, the temperature of the screws is gradually increased, the length-diameter ratio of the screws from the first-stage micro-screw device to the fourth-stage micro-screw device is 15-40 mm, the length-diameter ratio of the screws is 30-80, the rotating speed of the screws is 100-420 rpm, the temperature of the jackets is 30-60 ℃, and the screws from the first-stage micro-screw device to the fourth-stage micro-screw device comprise one or more single-head screws, double-head screws, three-head screws or four-head screws.

The post-treatment system comprises an auxiliary agent adding and mixing device, a filter, a defoaming kettle and a spinning solution storage tank;

under the same technical idea, the invention also provides a device for preparing the modified meta-aramid fiber by continuous polymerization-dry-wet spinning, which comprises the continuous polymerization device, and the continuous polymerization device is connected with a spinning system.

The spinning system comprises a spinning system, a solidification water washing system, a drying system, a heat treatment system, a winding/cutting system and a heat exchange system.

The spinning system can comprise a plurality of spinning nozzles to improve the production efficiency, and the constant temperature and humidity are kept to ensure the process stability, and the filament yarns are extruded by the spinning nozzle and then pass through a section of air layer, volatilize partial solvent and preliminarily pre-fetch and then enter a coagulating bath, so that the defects of holes, surface grooves and the like can be effectively reduced.

Preferably, the spinning system is provided with a gas cavity in an air section between the spinneret plate and the coagulating bath, and the gas cavity is provided with an air inlet/outlet.

The gas cavity can realize the control of the temperature in the cavity and the fiber solidification forming process by controlling the gas temperature and the flow velocity, and further regulate and perfect the fiber shape and the microstructure, thereby improving the performance and the batch stability of the fiber.

The gas in the gas chamber can be a single gas or a multi-component gas, preferably an inert gas or a combination thereof.

Preferably, the gas cavity is provided with two gas inlets/outlets which are not in the same horizontal position, wherein one of the gas inlets/outlets is a gas inlet, and the other gas outlet is a gas outlet.

The flow direction of the gas in the gas cavity can be from top to bottom, or from bottom to top, preferably from bottom to top; the gas temperature and the gas replacement rate in the gas cavity can be regulated and controlled according to the characteristics of the spinning solution and the spinning process in the spinning process.

The coagulation water washing system comprises a first coagulation bath, a second coagulation bath and a water washing device, a large amount of solvent is removed, and the nascent fiber forms a certain crystal orientation structure.

The heat treatment system comprises a dry heat stretching and heat setting device, the nascent fiber is further subjected to crystallization orientation through dry heat stretching, and the internal structure is further perfected through heat setting, so that the fiber with smooth surface, perfect microstructure and excellent performance is obtained.

Compared with the prior art, the invention has the beneficial effects that:

1) the heart-shaped microreactor is adopted for prepolymerization, the micro structure in the microreactor enables microreactor equipment to have a very large specific surface area which can be hundreds of times or even thousands of times of the specific surface area of a stirred tank, and instantaneous uniform mixing and heat transfer of materials can be realized. Acyl chloride and diamine are rapidly mixed and release heat in the microreactor, and heat is exchanged in the heart-shaped micro-reaction channels which are overlapped and connected in series up and down, so that the heat transfer problem is solved, and the side reaction is avoided. The micro-reactor has excellent heat transfer effect, and effectively transfers the heat emitted by the reaction system at the initial stage of polymerization; the temperature of the system can be accurately controlled, the generation of byproducts caused by local overheating of the system is prevented, the low polydispersity of resin molecules of the product is ensured, and the stable and controllable intrinsic viscosity is ensured.

2) The multi-stage screw is adopted for polycondensation, so that the mass transfer problem is solved, and the resin stock solution with high molecular weight and high solid content (high viscosity) is obtained. And the low-viscosity polymer from the microreactor enters a multistage micro-screw device, the multistage micro-screw device is mainly used for solving the mass transfer problem after the viscosity of a polymerization system in the third stage of reaction is rapidly increased, and the viscosity of the polymer is rapidly increased in the multistage micro-screw device.

3) A multistage micro-screw device is adopted to be matched with a pre-polymerization micro-reactor, acyl chloride and diamine stably enter a micro-channel through a metering system for mixing and heat exchange, and then enter and exit the multistage micro-screw device, a neutralization system, a filtration system and a defoaming system in sequence. Ensuring the continuous and stable operation of the reaction device. The mass transfer requirements of the aramid fiber polymerization process in the polycondensation stage are met by adjusting the rotating speed of the micro-screw device in different stages and the retention time of materials, and different requirements can be met simultaneously; compared with the traditional reaction kettle, the continuous micro-reaction device has no amplification effect and is suitable for industrial large-scale continuous production.

4) The spinning system adds a gas chamber in conventional air layer section to be furnished with air inlet and gas outlet, can realize the control to intracavity temperature and fibre solidification forming process through control gas temperature and velocity of flow, and then regulate and control and perfect fibre form and microstructure, thereby promote fibrous performance and batch stability.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of the overall structure of a heart-shaped microreactor in example 1;

FIG. 2 is a schematic diagram showing the connection relationship between the upper cover plate and the bottom plate of the heart-shaped microreactor and the heart-shaped microreactor in example 1;

FIG. 3 is a schematic view showing a structure of connecting a heart-shaped micro-reaction chamber and a micro-channel in example 1;

FIG. 4 is a schematic diagram of a system for preparing meta-aramid fiber by continuous polymerization-dry-wet spinning of example 1;

FIG. 5 is a schematic view of a dry-wet spinning dry-jet apparatus of example 1.

In the figure: 1. a isophthaloyl dichloride raw material storage tank; 2. a metaphenylene diamine and third monomer raw material storage tank; 3. a solvent storage tank; 4. a solvent raw material storage tank containing a cosolvent; 5. a dewatering device; 6. a three-way valve; 7. a advection pump; 8. a heat-preserving jacket; 9. a micro mixer; 10. a microreactor; 11. a multistage micro-screw device; 12. an auxiliary agent adding and mixing device; 13. a filter; 14. a deaeration kettle; 15. a spinning solution storage tank; 16. a metering pump; 17. a spinning filter; 18. a spinneret assembly; 19. a coagulation bath; 20. a first coagulation bath; 21. a second coagulation bath; 22. a water washing system; 23. a tractor; 24. a drying system; 25. a dry heat stretching device; 26. a heat setting device; 27. a winding/cutting system; 28. a refrigeration medium storage tank; 29. a heating medium storage tank; 30. a heat exchange medium delivery pump; 31. an upper cover plate; 32. a base; 33. a first feed channel; 34. a second feed channel; 35. a discharge channel 36, a heat transfer medium channel; 37. a first microchannel; 38. a second microchannel; 39. a heart-shaped micro-reaction chamber; 40. a third microchannel; 41. a heart-shaped micro-reaction chamber unit; 50. a spinneret plate; 52. a gas chamber; 53. an air inlet/outlet.

Detailed Description

In order to facilitate understanding of the invention, the invention will be described more fully and in detail with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1:

as shown in fig. 1, 2 and 3, the heart-shaped microreactor of this embodiment includes an upper cover plate 31 and a base 32, wherein the upper cover plate 31 is provided with a first feeding channel 33, a second feeding channel 34 and a discharging channel 35, and the upper cover plate 31 and the base 32 are provided with a heat transfer medium channel 36 for conveying a heat transfer medium; the first feed channel 33 and the second feed channel 34 are respectively connected with a first micro-channel 37 and a second micro-channel 38, the first micro-channel 37 and the second micro-channel 38 are merged and then connected with a heart-shaped micro-reaction chamber 39, the heart-shaped micro-reaction chamber 39 is connected with a third micro-channel 40, and the third micro-channel 40 is connected with a discharge channel 35.

The arrow a is the flow direction of the reaction materials in the heart-shaped microreactor;

arrow b is a schematic diagram of the flow direction of the heat transfer medium in the heart-shaped microreactor;

the heart-shaped micro reaction chambers 39 are connected in series through micro channels, every two heart-shaped micro reaction chambers 39 are arranged in an up-and-down overlapping mode to form a group of heart-shaped micro reaction chamber units 41, and the heart-shaped micro reaction chamber units 41 are connected in series through the micro channels; two heart-shaped micro reaction chambers 39 in the heart-shaped micro reaction chamber unit 41 are connected end to end through micro channels, the micro channels at the end of the feeding channel are connected with the concave part of the heart-shaped micro reaction chamber 39, the micro channels at the end of the discharging channel are connected with the heart tip part of the heart-shaped micro reaction chamber 39, and the heart-shaped micro reaction chamber 39 has a round and irregular hollow structure.

The embodiment of the invention is carried out in a device for preparing modified meta-aramid fiber by continuous polymerization-dry-wet spinning, and referring to fig. 1, the device comprises the following systems:

raw material storage device: comprises a isophthaloyl dichloride raw material storage tank 1, a m-phenylenediamine and third monomer raw material storage tank 2, a solvent storage tank 3, a cosolvent-containing solvent raw material storage tank 4 and a dewatering device 5; in the raw material storage device, a solvent raw material storage tank 4 containing a cosolvent is connected to a dehydration device 5, the dehydration device 5 and a solvent storage tank 3 are connected to a m-phenylenediamine and third monomer raw material storage tank 2, a isophthaloyl dichloride raw material storage tank 1 is connected to an advection pump 7 and the solvent storage tank 3 through a three-way valve 6, the advection pump 7 is connected to a micromixer 9, and the m-phenylenediamine and third monomer raw material storage tank 2 is also connected to the micromixer 9 through an advection pump; the isophthaloyl dichloride raw material storage tank 1, the m-phenylenediamine and third monomer raw material storage tank 2, the advection pump 7 and the conveying pipeline are all sleeved with a heat-preservation jacket 8 for controlling the temperature of the raw materials before entering the micro mixer;

a prepolymerization system: comprises a micromixer 9, a microreactor 10, a metering pump, a conveying pipe valve and instruments (a pressure gauge and a thermometer); the micro-mixer 9 is connected with a micro-reactor 10, the micro-reactor is a heart-shaped micro-reactor, the micro-reactor is designed into a heart shape, a plurality of heart-shaped micro-reactors are connected by micro-channels, and the micro-channels are respectively connected with the tip and the concave part of the heart shape;

③ polycondensation system: a multistage micro-screw device 11; the multistage micro-screw device 11 is connected with the microreactor 10;

fourthly, the post-processing system: comprises an auxiliary agent adding and mixing device 12, a filter 13, a defoaming kettle 14 and a spinning solution storage tank 15;

a spinning system: comprises a metering pump 16, a spinning filter 17 and a spinning assembly 18, wherein the spinning assembly comprises a spinning nozzle, a spinning plate and the like;

in fig. 5 c shows the spin pre-orientation in dry-wet spinning.

Sixthly, solidifying and washing the system: comprises a coagulation bath 19, a first coagulation bath 20, a second coagulation bath 21 and a water washing system 22; the washing system 22 comprises a washing machine, a washing liquid storage tank, a drawing roller and the like;

as shown in fig. 5, the air section of the spinning system between the spinneret plate 50 and the coagulation bath 19 is provided with a gas cavity 52, the gas cavity 52 is provided with an air inlet/outlet 53, and the air inlet and the air outlet are not in the same horizontal position;

and a drying system 24: comprises a dryer and a drawing roller;

and (v) a heat treatment system: comprises a dry heat stretching device 25, a heat setting device 26, a nitrogen system and a drawing roller;

ninthly winding/cutting system 27: including a winder/cutter;

the solidification washing system, the drying system 24, the heat treatment system device, and the winding/cutting system 27 are connected to each other by a tractor 23;

r heat exchange system: comprises a refrigeration medium storage tank 28, a heating medium storage tank 29, a heat exchange medium delivery pump 30, a heat exchange medium storage tank and a rotor flow meter. A heat exchange medium delivery pump 30 and a rotor flow meter are connected between the refrigeration medium storage tank 28 and the micro mixer 9, and a medium delivery pipeline connects the refrigeration medium storage tank 28, the micro mixer 9 and the microreactor 10 to form a circulation loop; a heat exchange medium delivery pump 30 and a rotor flow meter are connected between the heating medium storage tank 29 and the multistage micro-screw device 11, and a medium delivery pipeline connects the heating medium storage tank 29 and the multistage micro-screw device 11 to form a circulation loop; the multistage micro-screw device 11 comprises a first-stage micro-screw device, a second-stage micro-screw device, a third-stage micro-screw device and a fourth-stage micro-screw device which are sequentially connected, wherein heat insulation jackets are respectively sleeved on the first-stage micro-screw device and the fourth-stage micro-screw device, a heat medium in the heating circulation device is introduced into the heat insulation jackets, the diameters of screws from the first-stage micro-screw device to the fourth-stage micro-screw device are gradually increased, the length-diameter ratio of the screws is gradually reduced, the rotating speed of the screws is gradually reduced, the temperature of the screws is gradually increased, the diameter of the screws from the first-stage micro-screw device to the fourth-stage micro-screw device is 15-40 mm, the length-diameter ratio of the screws is 30-80, the rotating speed of the screws is 100-420 rpm, the temperature of the jackets is 30-60 ℃, and the screws from the first-stage micro-screw device to the fourth-stage micro-screw device can be single-head screws, double-head screws, three-head screws or four-head screws.

The preparation process of the continuous polymerization-dry wet spinning of the embodiment is as follows:

as shown in the scheme of FIG. 4, a mixed DMAc solution of LiCl (2%) containing m-phenylenediamine and 6,4 '-diamino-2' -trifluoromethyl-2-phenylbenzimidazole (98: 2 molar ratio) was prepared at a solids content of 10 wt% and maintained at-20 ℃ while melting isophthaloyl dichloride and maintaining at 55 ℃; metering the mixed solution and the isophthaloyl dichloride cylinder according to an equimolar amount by using an advection pump, mixing the mixed solution by using a micro mixer 9, and conveying the mixed solution to a heart-shaped micro reactor 10, wherein the temperatures of the micro mixer 9 and the micro reactor 10 are controlled at-20-10 ℃ and 10-30 ℃ respectively; the prepolymer flowing out of the microreactor 10 flows into a first-stage micro-screw device to a fourth-stage micro-screw device for polycondensation, wherein the screw diameter of the first-stage micro-screw device is 15mm, the length-diameter ratio is 80, the rotating speed is 420rpm, the jacket temperature is 30 ℃, the screw diameter of the second-stage micro-screw device is 20mm, the length-diameter ratio is 60, the rotating speed is 300rpm, the jacket temperature is 40 ℃, the screw diameter of the third-stage micro-screw device is 30mm, the length-diameter ratio is 40, the rotating speed is 220rpm, the jacket temperature is 50 ℃, the screw diameter of the fourth-stage micro-screw device is 40mm, the length-diameter ratio is 30, the rotating speed is 100rpm, and the jacket temperature is 60 ℃; the screws from the first-stage micro screw device to the fourth-stage micro screw device are all four-head screws; the polymer flowing out of the multistage micro-screw device 11 enters a post-treatment system, and is added with 1 wt% of trifluoroethanol, filtered and defoamed to obtain a spinning solution; and (3) carrying out spinning, washing, drying, dry heat stretching, heat setting, rolling or cutting on the spinning stock solution to obtain the modified meta-aramid fiber. Wherein the aperture of the spinneret plate is 0.12mm, the height of the air layer is 40mm, and the pre-orientation drawing speed is 3.5 times of the spinning speed of the stock solution; the DMAc concentration of the first coagulation bath was 25 wt%, the temperature was 40 ℃; the concentration of DMAc in the second coagulating bath is 20 wt%, the temperature is 55 ℃, and the plasticizing and stretching multiple is 3.0; the dry heat stretching temperature is 310 ℃, and the stretching multiple is 2.0; the heat-setting temperature was 320 ℃.

Example 2:

the reaction apparatus was the same as in example 1, the spinneret hole diameter in example 1 was adjusted to 0.1mm, the air layer was adjusted to 20mm, and the first drawing roller speed was adjusted to 3.0 times the spinning dope speed; the concentration of DMAC in the first coagulation bath is adjusted to be 35 percent, the temperature is adjusted to be 40 ℃, the concentration of DMAC in the second coagulation bath is adjusted to be 25 percent, the temperature is adjusted to be 45 ℃, and the plasticizing and stretching ratio is adjusted to be 2.5; the other processes and process parameters were the same as in example 1.

Example 3:

the reaction apparatus was the same as in example 1, except that the height of the air layer in example 1 was adjusted to 10mm, the speed of the first drawing roll was adjusted to 2.0 times the speed of the spinning dope, the temperature of the first coagulation bath was adjusted to 35 ℃, the temperature of the second coagulation bath was adjusted to 45 ℃, and the plasticizing stretch ratio was adjusted to 2.8; the other processes and process parameters were the same as in example 1.

Example 4:

the reaction apparatus was the same as in example 1, and the air layer height in example 1 was adjusted to 60mm, and the first draw roller speed was adjusted to 4.0 times the dope speed; the concentration of DMAC in the first coagulation bath is adjusted to be 30 percent, the temperature is adjusted to be 25 percent, the concentration of DMAC in the second coagulation bath is adjusted to be 25 percent, the temperature is adjusted to be 35 percent, and the plasticizing stretching ratio is adjusted to be 3.2; the other processes and process parameters were the same as in example 1.

Example 5:

the reaction apparatus was the same as in example 1, and the dry heat stretching temperature in example 1 was adjusted to 300 ℃ and the magnification was adjusted to 1.8; the heat setting temperature is adjusted to 310 ℃; the other processes and process parameters were the same as in example 1.

Example 6:

the reaction apparatus was the same as in example 1, and the dry heat stretching temperature in example 1 was adjusted to 320 ℃ and the magnification was adjusted to 2.4; the heat setting temperature is adjusted to 330 ℃; the other processes and process parameters were the same as in example 1.

Example 7:

the reaction device is the same as that in the example 1, the third monomer in the example 1 is changed into 2- (4-aminophenyl) -5-aminophenylbenzimidazole, the molar ratio of the m-phenylenediamine to the third monomer is 95:5, the using amount of LiCl is adjusted to 4%, the auxiliary agent is adjusted to 0.05% of glycerol, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Example 8:

the reaction device is the same as that in the example 1, the third monomer in the example 1 is changed into 5-amino-2- (4-aminophenyl) benzoxazole, the molar ratio of the m-phenylenediamine to the third monomer is 97:3, the auxiliary agent is adjusted to 1.5% polyether modified polysiloxane, the LiCl dosage is adjusted to 3%, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Example 9:

the reaction device is the same as that in the example 1, the third monomer in the example 1 is changed into 5-amino-2- (4-aminophenyl) benzothiazole, the molar ratio of the m-phenylenediamine to the third monomer is 96:4, the dosage of LiCl is adjusted to be 4 percent, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Example 10:

the reaction device is the same as that in the example 1, the third monomer in the example 1 is changed into 2, 6-diaminobenzothiazole, the auxiliary agent is adjusted to be 0.3 percent sorbic acid, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Example 11:

the reaction device is the same as that in the embodiment 1, the third monomer in the embodiment 1 is changed into 2, 6-diaminopyridine, the assistant is adjusted to be 0.1 percent of salicylic acid, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Example 12:

the reaction device is the same as that in the example 1, the third monomer in the example 1 is changed into 2- (4-aminophenyl) -5-aminopyridine, the auxiliary agent is adjusted to be 0.2 percent of trifluoroacetamide, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Example 13:

the reaction apparatus was the same as in example 1, the third monomer in example 1 was changed to 2, 5-bis (4-aminophenyl) pyridine, the assistant was adjusted to 2% hydroxy group-containing polysiloxane, and other processes and parameters were not changed to obtain a modified m-aramid fiber.

Example 14:

the reaction apparatus was the same as in example 1, the third monomer in example 1 was replaced with o-chloro-p-phenylenediamine, and the molar ratio of m-phenylenediamine to the third monomer was 95: and 5, adjusting the using amount of LiCl to 1%, adjusting the auxiliary agent to 0.2% trifluoroacetic acid, and keeping other processes and parameters unchanged to obtain the modified meta-aramid fiber.

Example 15:

the reaction device is the same as that in the embodiment 1, the third monomer in the embodiment 1 is changed into p-phenylenediamine, the auxiliary agent is adjusted to be 0.8% of fluorine-containing siloxane, and other processes and parameters are not changed, so that the modified meta-aramid fiber is obtained.

Comparative example 1: pure meta-aramid, batch polymerization-wet spinning

The meta-aramid fiber is prepared by adopting the traditional kettle type intermittent polymerization, the inherent viscosity of the resin is 1.84, the molecular weight distribution is 1.49, the viscosity at 50 ℃ is 28000cp, and the meta-aramid fiber is obtained by adopting a wet spinning method.

Comparative example 2: pure meta-aramid fiber, intermittent polymerization-dry wet spinning

The polymerization method is the same as that of the comparative example 1, the viscosity at 50 ℃ is 80000cp, and the phenomenon of 'plate pasting' occurs when spinning is carried out by adopting a dry-wet method.

Comparative example 3: pure meta-aramid fiber, continuous polymerization-wet spinning

The meta-aramid fiber is prepared by continuous polymerization, the inherent viscosity of the resin is 1.82, the molecular weight distribution is 1.39, the viscosity at 50 ℃ is 36000cp, and the meta-aramid fiber is obtained by wet spinning.

Comparative example 4: pure meta-aramid fiber, continuous polymerization-dry wet spinning

The polymerization method is the same as the comparative example 3, the viscosity at 50 ℃ is 76000cp, the spinning is carried out by adopting a dry-wet method, the spinnability of the spinning solution is general, and broken filaments appear.

Comparative example 5: pure meta-aramid fiber, continuous polymerization, addition of assistant, dry-wet spinning

0.5 wt% of ethylene glycol is added into the meta-aramid resin solution of the comparative example 4, the viscosity at 50 ℃ is 82000cp, the meta-aramid fiber is obtained by adopting dry-wet spinning, the spinnability of the spinning solution is improved to a certain extent compared with that of the comparative example 4, and the frequency of broken filaments and broken filaments is reduced.

Comparative example 6: modified meta-aramid fiber, continuous polymerization-dry wet spinning

The modified meta-aramid fiber with the third monomer of o-chloro-p-phenylenediamine of which the content is 2 percent (mole fraction) is prepared by continuous polymerization, the inherent viscosity of the resin is 2.08, the molecular weight distribution is 1.41, the viscosity at 50 ℃ is 70000cp, the meta-aramid fiber is obtained by dry-wet spinning, the spinnability of a spinning stock solution is improved to a certain extent compared with that of a comparative example 4, and the frequency of broken filaments and broken filaments is reduced.

TABLE 1 comparison of the properties of the examples with those of the comparative examples

Claims (11)

1. A heart-shaped microreactor comprises an upper cover plate (31) and a base (32), and is characterized in that the upper cover plate (31) is provided with a first feeding channel (33), a second feeding channel (34) and a discharging channel (35), and the upper cover plate (31) and the base (32) are provided with heat transfer medium channels (36) for conveying heat transfer media; the first feed channel (33) and the second feed channel (34) are respectively connected with the first micro channel (37) and the second micro channel (38), the first micro channel (37) and the second micro channel (38) are connected with the heart-shaped micro reaction chamber (39) after being converged, the heart-shaped micro reaction chamber (39) is connected with the third micro channel (40), and the third micro channel (40) is connected with the discharge channel (35).

2. Heart-shaped microreactor according to claim 1, wherein the heart-shaped microreactors (39) are connected in series by microchannels, every two heart-shaped microreactors (39) are arranged one above the other to form a group of heart-shaped microreactor units (41), and a plurality of heart-shaped microreactor units (41) are connected in series by microchannels.

3. Heart-shaped microreactor according to claim 2, wherein two heart-shaped microreactors (39) in a heart-shaped microreactor unit (41) are connected end to end by microchannels, wherein a microchannel at the end of a feed channel connects a concave portion of a heart-shaped microreactor (39), and a microchannel at the end of a discharge channel (35) connects a cardiac apex portion of a heart-shaped microreactor (39).

4. Heart-shaped microreactor according to any of claims 1-3, wherein the heart-shaped microreactor (39) has a hollow structure.

5. A continuous polymerization device comprises a raw material storage device, a prepolymerization system, a polycondensation system, a post-treatment system and a heat exchange system; prepolymerization system, polycondensation system and aftertreatment system connect gradually, heat transfer system respectively with prepolymerization system and polycondensation system connection control prepolymerization system and polycondensation system's temperature, the prepolymerization system is including the micromixer (9) and the microreactor (10) that connect gradually, the polycondensation system includes multistage little screw device (11), and microreactor (10) are connected with multistage little screw device (11), its characterized in that, microreactor (10) are heart-shaped microreactor.

6. The device according to claim 5, wherein the raw material storage device comprises a isophthaloyl dichloride raw material storage tank (1), a m-phenylenediamine and third monomer raw material storage tank (2), a solvent storage tank (3) and a solvent raw material storage tank (4) containing a cosolvent, and the isophthaloyl dichloride raw material storage tank (1), the m-phenylenediamine and the third monomer raw material storage tank (2) are respectively connected with the micromixer (9) through an advection pump (7) and a conveying pipeline.

7. The apparatus according to claim 6, wherein a solvent dehydration apparatus (5) is connected between the m-phenylenediamine and co-phenylenediamine monomer raw material tank (2) and the cosolvent-containing solvent raw material tank (4); and the isophthaloyl dichloride raw material storage tank (1), the m-phenylenediamine and third monomer raw material storage tank (2), the advection pump (7) and the conveying pipeline are all sleeved with a heat-insulating jacket (8).

8. The apparatus according to claim 7, wherein the heat exchange system comprises a refrigeration cycle apparatus and a heating cycle apparatus, the refrigeration cycle apparatus comprises a refrigeration medium storage tank (28), a heat exchange medium delivery pump (30), a rotameter and a medium delivery pipeline, the heat exchange medium delivery pump (30) and the rotameter are connected between the refrigeration medium storage tank (28) and the micromixer (9), and the medium delivery pipeline connects the refrigeration medium storage tank (28), the micromixer (9) and the microreactor (10) to form a circulation loop; the heating circulation device comprises a heating medium storage tank (29), a heat exchange medium delivery pump (30), a rotor flow meter and a medium delivery pipeline, wherein the heat exchange medium delivery pump (30) and the rotor flow meter are connected between the heating medium storage tank (29) and the multistage micro-screw device (11), and the medium delivery pipeline connects the heating medium storage tank (29) and the multistage micro-screw device (11) to form a circulation loop;

the multistage micro-screw device (11) comprises a first-stage micro-screw device, a second-stage micro-screw device, a third-stage micro-screw device and a fourth-stage micro-screw device which are sequentially connected, wherein heat insulation jackets (8) are sleeved on the first-stage micro-screw device and the fourth-stage micro-screw device, a heat medium in the heating circulation device is introduced into the heat insulation jackets (8), the diameters of screws from the first-stage micro-screw device to the fourth-stage micro-screw device are gradually increased, the length-diameter ratio of the screws is gradually reduced, the rotating speed of the screws is gradually increased, the temperature of the screws is gradually increased, the diameters of screws from the first-stage micro-screw device to the fourth-stage micro-screw device are 15-40 mm, the length-diameter ratio of the screws is 30-80, the rotating speed of the screws is 100-420 rpm, the temperature of the jackets is 30-60 ℃, and the screws from the first-stage micro-screw device to the fourth-stage micro-screw device comprise one or more than one single-head screws, double-head screws, three-head screws, and four-head screws.

9. An apparatus for preparing modified meta-aramid fiber by continuous polymerization-dry-wet spinning, which is characterized by comprising the continuous polymerization apparatus as claimed in any one of claims 2 to 8, wherein the continuous polymerization apparatus is connected with a spinning system.

10. The device for preparing the modified meta-aramid fiber through continuous polymerization-dry wet spinning as claimed in claim 9, wherein the spinning system comprises a spinning system, a solidification water washing system, a drying system (24), a heat treatment system, a winding/cutting system (27) and a heat exchange system, the spinning system is provided with a gas cavity (52) in an air section between the spinneret plate (50) and the solidification bath (19), and the gas cavity (52) is provided with an air inlet/outlet (53).

11. The device for preparing the modified meta-aramid fiber through continuous polymerization-dry wet spinning as claimed in claim 9 or 10, wherein the gas chamber (52) is provided with two gas inlet/outlet ports (53) which are not in the same horizontal position, one of the gas inlet ports is a gas inlet port, and the other gas outlet port is a gas outlet port.

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