High-solid-content dry-method acrylic fiber spinning process

Abstract

The invention discloses a high-solid-content dry-process acrylic fiber spinning process, and belongs to the technical field of dry-process acrylic fibers. The preparation method comprises the following steps: (1) preparing a spinning solution, namely adding polyacrylonitrile dry powder into a solvent to prepare the spinning solution with the solid content of 31.0-32.0% by taking polyacrylonitrile as a raw material and dimethylacetamide as the solvent; (2) filtering: heating the spinning solution, and filtering through a plate-and-frame filter; (3) spinning forming: pressurizing the filtered spinning solution to enter a spinning pipeline, spraying the spinning solution through a spinning hole in a spinning plate, entering a channel, and drying the spinning solution in the channel to form nascent fibers; (4) washing and drafting: washing and drafting the nascent fiber; and (5) oiling, curling and drying: oiling, curling and drying the drafted tows to obtain the acrylic fibers. The invention provides a high-solid-content dry-method acrylic fiber spinning process taking dimethylacetamide as a solvent, the process is suitable for industrial large-scale production, the production rate and the fiber yield can be improved, and the energy consumption of a device can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of dry-process acrylic fibers, and in particular relates to a high-solid content dry-process acrylic fiber spinning process. Background Art

[0002] Acrylic is the trade name of polyacrylonitrile fiber (PAN) in China, which is one of the three major varieties of synthetic fibers. Acrylic has excellent properties, soft feel, good elasticity, and excellent light and weather resistance. According to its spinning process, it can be divided into dry acrylic and wet acrylic. The unique dogbone structure of dry acrylic makes its properties close to natural wool. The fabric made of dry acrylic has good elasticity and light weight. The finished product has the advantages of warmth, comfort, and elegant luster, which are irreplaceable by wet acrylic.

[0003] At present, the dry acrylic spinning process generally uses dimethylformamide (DMF) as the solvent, and the solid content of the spinning solution is 33.0% to 34.0%. In order to solve the problem of waste gas emissions, it is necessary to gradually replace DMF with dimethylacetamide (DMAC). Due to the many differences in the physical properties of the two solvents, the dissolution effect on the polymer is different. At the same time, the evaporation rate of the solvent in the spinning channel and the forming conditions of the primary yarn are changed, and the original spinning process control indicators cannot be used for production. In order to meet the requirements of spinning production, the solid content of dry acrylic spinning solution using DMAC as solvent is generally controlled at 28.5% to 30.0%. However, when the solid content of the spinning solution is controlled at a lower level, the viscosity of the spinning solution will also be lower. After the spinning solution is extruded from the spinneret, the spinning solution will quickly flow along the surface of the spinneret, and the spinning is easily interrupted, resulting in unstable production. At the same time, if the solid content of the spinning solution is low, the amount of solvent volatilization in the spinning channel will increase, and insufficient solvent volatilization may occur. The monofilaments are easily bonded together to form defects, affecting product quality. In addition, the lower solid content of the solution leads to a larger amount of solvent that needs to be evaporated in the channel, resulting in increased material consumption of the device and increased production costs.

[0004] Patent CN114164503B discloses a method for dry acrylic spinning and a method for preparing a stock solution. By increasing the temperature of dimethylacetamide and then using a Mark mixer to evenly dissolve it to prepare a spinning stock solution, the solubility of polyacrylonitrile powder in dimethylacetamide is improved, and the white core phenomenon in the stock solution is reduced. The focus of this patent is to improve the solubility of polyacrylonitrile powder in DMAC and the preparation process of the stock solution, and it does not involve the regulation of the spinning process control index. At the same time, the high-temperature stirring and dissolving dry powder process is prone to produce dry powder lumps, which makes the stock solution easy to block the filter cloth when passing through the filter, and it is easy to cause problems such as doubling when forming in the tunnel, resulting in the acrylic fiber tow having defects, low strength, and poor spinnability.

[0005] Patent CN113584607A discloses an acrylic fiber spinning solution and its preparation method and application. The acrylic fiber spinning solution is obtained by treating polyacrylonitrile polymer with sodium thiocyanate aqueous solution. The problems of large viscosity fluctuation of acrylic fiber spinning solution and abnormal color of intermediate products are solved by controlling the content of aluminum and iron in the acrylic fiber spinning solution. The spinning solution described is used in the production of acrylic fiber prepared by sodium thiocyanate two-step wet spinning, but cannot be used in the production of dry acrylic fiber spinning. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a high-solid content dry acrylic spinning process using dimethylacetamide as a solvent, which is suitable for industrial large-scale production and can increase the production rate and fiber output and reduce the energy consumption of the device.

[0007] In order to achieve the above object, according to one aspect of the present invention, a high solid content dry acrylic spinning process is provided, comprising the following steps: (1) Preparation of spinning solution: using polyacrylonitrile as raw material and dimethylacetamide as solvent to prepare a spinning solution with a solid content of 31.0-32.0%; (2) Filtration: The spinning solution is heated to 110-115° C. and filtered through a plate and frame filter. The temperature of the solution delivery pipeline and the jacket water of the plate and frame filter is set to 112-117° C.; (3) Spinning: The filtered spinning solution is pressurized to 1.75-2.3 MPa and enters the spinneret. After being ejected from the spinneret holes on the spinneret plate, it enters the tunnel and is dried by nitrogen in the tunnel to form primary fibers. (4) washing and stretching: washing and stretching the spun fibers, wherein the water tank temperature of the stretching machine is controlled at 80-100° C.; (5) Drawing, oiling, curling and drying: The filament bundles after washing and drawing are oiled, curled and dried to obtain acrylic fiber.

[0008] In some embodiments, in step (1), the process conditions for preparing the spinning solution are: heating dimethylacetamide to 75-79° C., spraying polyacrylonitrile with dimethylacetamide, so that the polyacrylonitrile is evenly soaked with dimethylacetamide.

[0009] In some embodiments, in step (3), the corridor is divided into four parts: an air chamber, a cone, an upper part of the upper corridor, and a lower part of the upper corridor. The temperature of the air chamber is 330-380°C, the temperature of the cone is 205-250°C, the temperature of the upper part of the upper corridor is 170-210°C, and the temperature of the lower part of the upper corridor is 150-180°C.

[0010] In some embodiments, in step (3), the nitrogen drying is specifically as follows: the main nitrogen enters from the spinning tunnel air chamber and flows in the same direction as the fiber running direction, the main nitrogen temperature is 330-380°C, and the main nitrogen pressure is 3.2-4.3 kPa.

[0011] In some embodiments, in step (3), the spinneret holes are arranged in a double layer of concentric circles on the spinneret plate.

[0012] In some embodiments, in step (3), the temperature of the inner layer spinneret holes is 130-140°C, and the temperature of the outer layer spinneret holes is 122-130°C.

[0013] In some embodiments, in step (4), the water tank temperature of the drawing machine is controlled at 80-100°C.

[0014] In some embodiments, in step (5), the oiling is performed twice; wherein the first oiling speed is 50-60 rpm, and the second oiling speed is 90-100 rpm.

[0015] In some embodiments, in step (5), the pressure of the upper curling roller is controlled at 0.1-0.4 MPa, and the pressure of the lower curling roller is controlled at 0-0.3 MPa.

[0016] In some embodiments, in step (5), the drying temperature is 120-140°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The invention provides a high-solid-content dry-method acrylic fiber spinning process using dimethylacetamide as a solvent, wherein the fluidity of the high-solid-content spinning solution is ensured by increasing the spinning solution temperature and the jacket water temperature, so that the solution can pass through a solution filter smoothly; and the spinnability of the fiber is ensured under the condition of high solid content by adjusting the main nitrogen pressure and temperature of the spinning machine, the temperature of the inner and outer rings, the temperature of each zone in the spinning tunnel, and the speed of the traction feeder, while the production rate of a single tunnel is increased and the energy consumption of the device is reduced. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0019] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0020] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0021] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0022] In the present invention, the high solid content means that the solid content of the spinning solution using dimethylacetamide as solvent is between 31% and 32%.

[0023] The present invention provides a high solid content dry acrylic fiber spinning process, comprising the following steps: (1) Preparation of spinning solution: using polyacrylonitrile as raw material and dimethylacetamide as solvent to prepare a spinning solution with a solid content of 31.0-32.0%; (2) Filtration: The spinning solution is heated to 110-115° C. and filtered through a plate and frame filter. The temperature of the solution delivery pipeline and the jacket water of the plate and frame filter is set to 112-117° C.; (3) Spinning: The filtered spinning solution is pressurized to 1.75-2.3 MPa and enters the spinneret. After being ejected from the spinneret holes on the spinneret plate, it enters the tunnel and is dried by nitrogen in the tunnel to form primary fibers. (4) washing and stretching: washing and stretching the spun fibers, wherein the water tank temperature of the stretching machine is controlled at 80-100° C.; (5) Drawing, oiling, curling and drying: The filament bundles after washing and drawing are oiled, curled and dried to obtain acrylic fiber.

[0024] According to the process of the present invention, polyacrylonitrile is used as raw material and dimethylacetamide is used as solvent to prepare a spinning solution with a solid content of 31.0-32.0%. The specific steps of preparing the spinning solution are: heating dimethylacetamide to 75-79°C, spraying polyacrylonitrile with dimethylacetamide, so that the polyacrylonitrile is evenly infiltrated with dimethylacetamide. Specifically, dimethylacetamide can be heated to 75-79°C, and the polyacrylonitrile is sprayed into the spray box in a weight ratio of 68-69:31-32. After the polyacrylonitrile is evenly infiltrated with dimethylacetamide, it enters the mixer for mixing, and then enters the mixing tank for stirring, so that the stock solutions produced before and after are mixed and enter the stock solution storage tank.

[0025] In the present invention, the number average molecular weight of the polyacrylonitrile is 30000-45000, and preferably, the polyacrylonitrile is polyacrylonitrile powder. The present invention has no specific limitation on the particle size of the polyacrylonitrile powder, and the conventional particle size in the field of fiber spinning can be used.

[0026] According to the process of the present invention, in some embodiments, in step (2), the spinning solution is heated to 110-115°C. The specific steps may be: the spinning solution is passed through the solution heater under the action of the solution feed pump to heat the spinning solution to 110-115°C. The present invention can better increase the fluidity of the high-solid content spinning solution by increasing the temperature of the spinning solution to the range, and at the same time increase the temperature of the solution delivery pipeline and the jacket water of the plate and frame filter to 112-117°C, so that the solution can pass through the plate and frame filter smoothly to filter out impurities and undissolved polymers.

[0027] The inventors of the present invention have found that for high-solid content spinning solution, due to its high viscosity, in order to ensure that the spinning solution flows through the inner and outer spinneret holes of the spinneret at a certain speed and pressure for shear flow, the pressure of the spinning solution needs to be increased to 1.75-2.3 MPa to ensure the inlet pressure of the spinning metering pump. Specifically, a solution booster pump can be used to increase the pressure of the spinning solution.

[0028] According to the process of the present invention, in some embodiments, in step (3), the spinneret holes are arranged in two layers of concentric circles on the spinneret plate, and further, the number of holes on the spinneret plate is 1860H or 2800H.

[0029] According to the process of the present invention, in some embodiments, in step (3), the temperature of the inner layer spinneret hole is 130-140°C, and the temperature of the outer layer spinneret hole is 122-130°C. Specifically, a double stock solution heater can be used to reheat the inner layer spinneret hole stock solution and the outer layer spinneret hole stock solution respectively. In the present invention, by heating the inner layer spinneret hole stock solution and the outer layer spinneret hole stock solution to different temperatures, overheating of the outer layer spinneret and insufficient drying of the inner layer spinneret can be avoided.

[0030] According to the process of the present invention, in some embodiments, in step (3), the tunnel is divided into four parts: an air chamber, a cone, an upper part of the upper tunnel, and a lower part of the upper tunnel. The temperature of the air chamber is 330-380°C, the temperature of the cone is 205-250°C, the temperature of the upper part of the upper tunnel is 170-210°C, and the temperature of the lower part of the upper tunnel is 150-180°C. The present invention can ensure the heat required for the continuous evaporation of the solvent in the tunnel by controlling the temperature of different parts of the tunnel, thereby avoiding the problem of insufficient solvent volatilization, and the formed primary fiber monofilaments are not easy to bond together, thereby ensuring product quality.

[0031] Furthermore, in some specific embodiments, the height of the spinning shaft can be 5-6m, and the spinning shaft is divided into four parts: an air chamber, a cone, an upper part of the upper shaft, and a lower part of the upper shaft. Each part is individually provided with an electric heater, and the temperature of each part is separately controlled by the electric heater.

[0032] According to the process of the present invention, in some embodiments, in step (3), the nitrogen drying is specifically as follows: the main nitrogen enters from the air chamber of the spinning tunnel and flows in the same direction as the fiber running direction, the main nitrogen temperature is 330-380°C, and the main nitrogen pressure is 3.2-4.3kPa. Specifically, the main nitrogen enters from the air chamber of the spinning tunnel after being heated by the nitrogen heater under the action of the steam turbine blower, and flows in the same direction as the fiber running direction, during which the main nitrogen completes mass transfer and heat transfer with the fiber, and the dimethylacetamide in the fiber is evaporated. After the main nitrogen carrying dimethylacetamide reaches the bottom of the spinning tunnel, it exits the tunnel from the nitrogen return valve, enters the nitrogen condenser to condense the dimethylacetamide, and the main nitrogen enters the turbine blower inlet for circulation.

[0033] The present invention maintains a certain main nitrogen temperature and pressure, so that the main nitrogen can run downward along the tunnel, drive the monofilament downward, and take away the evaporated solvent, thereby reducing the solvent content in the spinning tunnel, increasing the evaporation rate of the solvent, and thus appropriately increasing the production rate. Too high a main nitrogen temperature will lead to excessive drying of the fibers in the outer spinneret holes, resulting in an increase in the broken fiber rate; too low a main nitrogen temperature will lead to insufficient drying of the fibers in the inner spinneret holes, resulting in adhesion to produce bonded fibers, and also causing dirty tunnels and the like.

[0034] The present invention further controls the motor frequency of the drafting machine, which can increase the running speed of the nascent fiber and reduce the running time of the nascent fiber in the spinning tunnel. The present invention combines and controls the running speed of the fiber, the temperature of each part in the tunnel, and the temperature and pressure of the main nitrogen gas, which can ensure the full evaporation of the solvent in the nascent fiber and the quality of the fiber, and can also increase the production rate of spinning.

[0035] According to the process of the present invention, in some embodiments, in step (4), the temperature of the water tank of the drawing machine is controlled at 80-100°C.

[0036] According to the process of the present invention, in some embodiments, in step (4), the motor frequency of the drawing machine is 24.0-45.0 Hz; Furthermore, preferably, the specific process of washing and stretching is: extracting the solvent dimethylacetamide in the spun fiber with desalted water, and stretching the spun fiber at the same time to order the macromolecules in the fiber and improve the strength and elongation of the fiber.

[0037] According to the process of the present invention, in some embodiments, in step (5), the oiling is performed twice; wherein the first oiling rotation speed is 50-60 rpm, and the second oiling rotation speed is 90-100 rpm.

[0038] Further, as a preference, the oiling process may be roller oiling, specifically, the oiling roller is immersed in an oil tank, the oiling roller is attached to the ribbon and rotates in the opposite direction, the oil agent adhered to the roller is transferred to the ribbon, and the oiling process is completed; the oiling process may also be oiling rod spray oiling, specifically, the oil agent is sprayed onto the passing fibers through the small holes on the oiling rod.

[0039] According to the process of the present invention, in some embodiments, in step (5), the pressure of the upper curling roller is controlled at 0.2-0.4 MPa, and the pressure of the lower curling roller is controlled at 0.1-0.3 MPa.

[0040] Furthermore, as a preference, the specific process of the curling is as follows: the fiber enters a four-roller curling machine after exiting the water tank of the water washing machine, the two upper rollers of the curling machine clamp the fiber and send it into a stuffing box of the curling machine, and under the obstruction of the lower roller with a slower rotation speed, the fiber is bent in the stuffing box, and the bend is shaped by steam to form a curl.

[0041] According to the process of the present invention, in some embodiments, in step (5), the drying temperature is 120-140°C.

[0042] Furthermore, as a preference, the specific process of the drying is: the fibers enter the dryer, and the heated air penetrates the fibers laid on the chain plates of the dryer to take away moisture in the fibers.

[0043] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0044] The raw materials used in the examples and comparative examples of the present invention are all commercially available, and their specific information is as follows: Polyacrylonitrile: number average molecular weight 30000-45000, manufacturer: Qilu Petrochemical Acrylic Fiber Factory.

[0045] Dimethylacetamide: Manufacturer: Shandong Jinmei Riyue Chemical Co., Ltd.

[0046] Examples 1-6 The high solid content dry acrylic spinning process described in Examples 1-6, the specific spinning process parameter configuration is shown in Table 1, and the process includes the following steps: (1) Preparation of spinning solution: Dimethylacetamide is heated to 75-79°C and sprayed with polyacrylonitrile in a weight ratio of 68-69:31-32 in a spray box. After the polyacrylonitrile is evenly soaked in dimethylacetamide, it is mixed in a mixer and then stirred in a mixing tank. The solution produced before and after is mixed and then enters a solution storage tank; (2) Filtration: The spinning solution is heated to a certain temperature and filtered through a plate and frame filter. The temperature of the solution delivery pipeline and the jacket water of the plate and frame filter is set to 112-117°C; (3) Spinning: The filtered spinning solution is pressurized to 1.75-2.3 MPa and enters the spinneret. It is ejected from the spinneret holes on the spinneret plate and then enters the tunnel. It is dried with nitrogen in the tunnel to form primary fibers. The spinneret holes on the spinneret plate are arranged in double-layer concentric circles.

[0047] (4) washing and stretching: washing and stretching the spun fibers, wherein the water tank temperature of the stretching machine is controlled at 80-100° C.; (5) Oiling, curling, and drying: The stretched filament bundle is oiled, curled, and dried at a temperature of 120-140°C to obtain acrylic fiber; wherein the oiling is performed twice; wherein the first oiling speed is 50-60 rpm, and the second oiling speed is 90-100 rpm; the pressure of the upper roller for curling is controlled at 0.1-0.4 MPa, and the pressure of the lower roller for curling is controlled at 0-0.3 MPa.

[0048] Table 1 Configuration of process parameters for high solid content dry acrylic spinning in Examples 1-6 .

[0049] Comparative Examples 1-6 The high solid content dry acrylic spinning process described in Comparative Examples 1-6, the specific spinning process parameter configuration is shown in Table 2, and the process includes the following steps: (1) Preparation of spinning solution: Dimethylacetamide is heated to 75-79°C and sprayed with polyacrylonitrile in a weight ratio of 68-69:31-32 in a spray box. After the polyacrylonitrile is evenly soaked in dimethylacetamide, it is mixed in a mixer and then stirred in a mixing tank. The solution produced before and after is mixed and then enters a solution storage tank; (2) Filtration: The spinning solution is heated to a certain temperature and filtered through a plate and frame filter. The temperature of the solution delivery pipeline and the jacket water of the plate and frame filter is set to 112-117°C; (3) Spinning: The filtered spinning solution is pressurized to 1.75-2.3 MPa and enters the spinneret. After being ejected from the spinneret holes on the spinneret plate, it enters the tunnel and is dried by nitrogen in the tunnel to form primary fibers. (4) washing and stretching: washing and stretching the spun fibers, wherein the water tank temperature of the stretching machine is controlled at 80-100° C.; (5) Oiling, curling, and drying: The stretched filament bundle is oiled, curled, and dried at a temperature of 120-140°C to obtain acrylic fiber; wherein the oiling is performed twice; wherein the first oiling speed is 50-60 rpm, and the second oiling speed is 90-100 rpm; the pressure of the upper roller for curling is controlled at 0.1-0.4 MPa, and the pressure of the lower roller for curling is controlled at 0-0.3 MPa.

[0050] Table 2 Comparative Examples 1-6 High Solid Content Dry Process Acrylic Spinning Process Parameter Configuration .

[0051] Performance Testing 100 tons of plates: The number of spinnerets that need to be replaced for every 100 tons of fiber produced is used as a standard for evaluating production stability. The fewer the number of spinnerets that need to be replaced, the more stable the spinning production and the more appropriate the spinning process parameters.

[0052] Energy consumption of the device: The electricity, steam, fresh water, nitrogen, circulating water, desalted water, compressed air and chilled water consumed in spinning production are converted into standard oil according to the standard oil coefficient, and then divided by the fiber output to obtain the standard oil consumption per ton of fiber. The specific standard oil coefficient is shown in Table 3.

[0053] Table 3 Standard oil coefficient .

[0054] Fiber output: Fiber output is warehouse data, which is obtained through statistical records during the actual production process.

[0055] Production rate: obtained through statistical records during the actual production process.

[0056] The performance test data of the high solid content dry acrylic spinning process of Examples 1-6 and Comparative Examples 1-6 are specifically shown in Table 4.

[0057] Table 4 Performance test data of high solid content dry acrylic spinning process of Examples 1-6 and Comparative Examples 1-6 .

[0058] The difference between Comparative Example 1 and Example 1 is that the temperature of the stock solution of the outer spinneret is too low, the difference between Comparative Example 2 and Example 2 is that the temperature of the stock solution of the outer spinneret is too high, the difference between Comparative Example 3 and Example 3 is that the stock solution delivery temperature and the jacket water temperature are too low, the difference between Comparative Example 4 and Example 4 is that the stock solution delivery temperature and the jacket water temperature are too high, the difference between Comparative Example 5 and Example 5 is that the temperature of the stock solution of the inner spinneret is too low, and the difference between Comparative Example 6 and Example 6 is that the temperature of the stock solution of the inner spinneret is too high. It can be seen from Table 4 that the number of plate sets per 100 tons of the high solid content dry acrylic spinning process in Examples 1-6 of the present application is significantly lower than that of the process in the comparative example, and at the same time, the energy consumption of the device of the process in the embodiment is also significantly lower than that of the process in the comparative example. Description: This application controls the spinning solution temperature, jacket water temperature, adjusts the main nitrogen pressure and temperature of the spinning machine, the temperature of the inner and outer rings, the temperature of each zone in the spinning channel, and the speed of the traction feeder, thereby ensuring the spinnability of the fiber under high solid content conditions, while improving the single-channel production rate and fiber output, reducing the use of plate jackets per hundred tons, and reducing the energy consumption of the device.

[0059] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A high solid content dry acrylic fiber spinning process, characterized in that: The steps include: (1) Preparation of spinning solution: using polyacrylonitrile as raw material and dimethylacetamide as solvent to prepare a spinning solution with a solid content of 31.0-32.0%; (2) Filtration: The spinning solution is heated to 110-115° C. and filtered through a plate and frame filter. The temperature of the solution delivery pipeline and the jacket water of the plate and frame filter is set to 112-117° C.; (3) Spinning: The filtered spinning solution is pressurized to 1.75-2.3 MPa and enters the spinneret. After being ejected from the spinneret holes on the spinneret plate, it enters the tunnel and is dried by nitrogen in the tunnel to form primary fibers. (4) washing and stretching: washing and stretching the spun fibers, wherein the water tank temperature of the stretching machine is controlled at 80-100° C.; (5) Drawing, oiling, curling and drying: The filament bundles after washing and drawing are oiled, curled and dried to obtain acrylic fibers.

2. The high solid content dry acrylic spinning process according to claim 1, characterized in that: In step (1), the process conditions for preparing the spinning solution are: heating dimethylacetamide to 75-79° C., spraying polyacrylonitrile with dimethylacetamide, so that the polyacrylonitrile is evenly infiltrated with dimethylacetamide.

3. The high solid content dry acrylic spinning process according to claim 1, characterized in that: In step (3), the corridor is divided into four parts: an air chamber, a cone, an upper part of the upper corridor, and a lower part of the upper corridor. The temperature of the air chamber is 330-380°C, the temperature of the cone is 205-250°C, the temperature of the upper part of the upper corridor is 170-210°C, and the temperature of the lower part of the upper corridor is 150-180°C.

4. The high solid content dry acrylic spinning process according to claim 1, characterized in that: In step (3), the nitrogen drying is specifically as follows: the main nitrogen enters from the spinning tunnel air chamber and flows in the same direction as the fiber running direction, the main nitrogen temperature is 330-380°C, and the main nitrogen pressure is 3.2-4.3 kPa.

5. The high solid content dry acrylic spinning process according to claim 1, characterized in that: In step (3), the spinneret holes are arranged in a double layer of concentric circles on the spinneret plate.

6. The high solid content dry acrylic spinning process according to claim 5, characterized in that: In step (3), the temperature of the inner layer spinneret holes is 130-140°C, and the temperature of the outer layer spinneret holes is 122-130°C.

7. The high solid content dry acrylic fiber spinning process according to claim 1, characterized in that: In step (4), the water tank temperature of the drawing machine is controlled at 80-100°C.

8. The high solid content dry acrylic fiber spinning process according to claim 1, characterized in that: In step (5), the oiling is performed twice; wherein the first oiling speed is 50-60 rpm, and the second oiling speed is 90-100 rpm.

9. The high solid content dry acrylic fiber spinning process according to claim 1, characterized in that: In step (5), the pressure of the upper curling roller is controlled at 0.1-0.4 MPa, and the pressure of the lower curling roller is controlled at 0-0.3 MPa.

10. The high solid content dry acrylic fiber spinning process according to claim 1, characterized in that: In step (5), the drying temperature is 120-140°C.