Equipment and method for preparing fine-denier high-strength UHMWPE (Ultra High Molecular Weight Polyethylene) fiber

Abstract

The invention relates to equipment and a method for preparing fine-denier high-strength UHMWPE (Ultra High Molecular Weight Polyethylene) fiber, which are characterized in that low-entanglement UHMWPE resin and a good solvent are proportionally added into a swelling kettle with a stirring function, and are heated to obtain a spinning solution; the spinning solution forms a high-viscoelastic gel solution through a double-screw extruder, and the high-viscoelastic gel solution enters a vertical spinning box to form gel raw filaments after being extruded by a distributed spinning assembly; the gel raw silk firstly passes through a cooling section in the vertical spinning box to form the gel raw silk; forming frozen collagen filaments with certain humidity through a steam azeotropic solvent removal section; and finally, through a constant-temperature dehumidification section, drafting by a set drafting ratio in the box body to obtain a dry-state precursor. And further drafting the dry precursor through a drafting ratio set by post-spinning equipment to obtain the fine-denier high-strength UHMWPE fiber. In the preparation process, the recovery rate of a good solvent is 98% or above; the fineness of the prepared finished product fine denier high-strength UHMWPE fiber is 0.1 to 0.7 dtex, the strength is 31 to 45 cN / dtex, and the modulus is 1200 to 1700 cN / dtex.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, especially fiber materials, and in particular to the technical field of preparing ultra-high molecular weight polyethylene fibers by dry spinning, and specifically to an efficient and energy-saving spinning process, equipment and fibers thereof for preparing fine-denier high-strength ultra-high molecular weight polyethylene fibers. Background Art

[0002] In the existing ultra-high molecular weight polyethylene fiber preparation and production technology, dry spinning refers to the preparation of ultra-high molecular weight polyethylene spinning solution by mixing and swelling ultra-high molecular weight polyethylene resin with high volatility solvents, such as decalin and other organic solvents. After the spinning solution is extruded from the spinneret, the decalin is vaporized and escaped in a high-temperature inert gas atmosphere to obtain dry gel precursor, which is then stretched at a high multiple to obtain high-strength and high-modulus polyethylene fibers.

[0003] At present, the domestic high-performance polyethylene fiber dry spinning technology has been industrialized. Its core technology is that after the raw material liquid is extruded through the spinneret, the volatile solvent decahydronaphthalene in the raw material liquid is vaporized in the high-temperature nitrogen and exchanges heat with the side-blown air and tunnel air under the spinneret. The gas in the recovery system needs to go through a series of high-energy consumption and high-power consumption equipment and processes such as compression-condensation-adsorption desorption-membrane separation to remove and recover the solvent, so as to form frozen collagen fibers from the raw material liquid. Summary of the invention

[0004] The purpose of the present invention is to propose a device and method for preparing fine-denier high-strength UHMWPE fibers in view of the fact that the energy consumption of blowing volatile solvents with traditional high-temperature inert gas flow during the above-mentioned spinning process is high, and the high temperature in the process is likely to cause the incompletely untangled ultra-high molecular weight polyethylene gel filaments to stick together or reversely dissolve in the solvent decalin that is not removed in time, resulting in the prepared fibers having problems such as fuzz, breakage or uneven fineness.

[0005] The main technical scheme of the present invention is: an equipment for preparing fine denier high-strength UHMWPE fiber, including swelling, extrusion and post-spinning equipment, characterized in that a distributed spinneret assembly and a vertical spinning box are arranged after the extrusion equipment; the distributed spinneret assembly includes a plurality of spinnerets with different apertures, arranged in a matrix or single row; the vertical spinning box includes a spinning cooling section, a steam azeotropic solvent removal section and a constant temperature dehumidification section from top to bottom; the steam azeotropic solvent removal section includes a vertical steam inner tube, and the vertical steam inner tube wall is provided with a steam spray shower corresponding to the filament bundle channel.

[0006] Furthermore, the middle of the cooling section is a filament channel arranged in a single row or matrix, and the periphery is a flowing freezing medium channel.

[0007] Furthermore, the middle of the steam azeotropic solvent removal section is a filament channel arranged in a single row, and a steam jet shower is placed on one side of the filament channel.

[0008] Furthermore, the middle of the steam azeotropic solvent removal section is a filament channel arranged in a matrix shape, and steam spray showers are placed on one side and the front and rear sides of the filament channel.

[0009] Furthermore, the vertical steam inner tube of the steam azeotropic solvent removal section is connected to the high-pressure steam network through a steam transition tank; the steam outlet of the steam azeotropic solvent removal section is provided with a steam regulating valve and a steam condensation solvent recovery pipeline.

[0010] Furthermore, the steam condensation solvent recovery pipeline is coiled around the periphery of the constant temperature dehumidification section tow channel.

[0011] The present invention also provides a method for preparing fine denier high-strength UHMWPE fiber, using the above-mentioned equipment, comprising the following steps: Adding low entanglement UHMWPE resin and good solvent in a proportion into a swelling kettle with stirring, heating and raising the temperature to obtain a spinning solution; The spinning solution is formed into a high-viscoelastic gel solution through a twin-screw extruder, which is extruded by a distributed spinneret assembly and then enters a vertical spinning box to form gel filaments. The gel precursor first passes through a cooling section in a vertical spinning box to form frozen gel precursor; then passes through a steam azeotropic solvent removal section to form frozen gel precursor with a certain humidity; finally passes through a constant temperature dehumidification section and is stretched at a set stretching ratio in the box to obtain dry precursor; The dry raw silk is further stretched at a stretching ratio set by the post-spinning equipment to produce fine denier and high-strength UHMWPE fiber.

[0012] Furthermore, in the step 1), the viscosity-average molecular weight of the UHMWPE resin is 4-6.5 million, and the degree of entanglement is 0.1-0.6; the good solvent is selected from decahydronaphthalene, tetrahydronaphthalene, and xylene; the ratio of UHMWPE resin to the good solvent is (5:94)-(12:88); after heating to 80°C, the temperature is gradually increased to 95°C at a rate of 5°C per hour and then stabilized for one hour.

[0013] Furthermore, in the cooling section, the temperature control range is -30°C-10°C, preferably -20°C-0°C, and more preferably -15°C--5°C.

[0014] Furthermore, in the steam azeotropic solvent removal section, the steam quality entering the spinning manifold is 90, the steam pressure is 50KPa-300KPa, preferably 80KPa-200KPa, more preferably 100KPa-160KPa; the temperature is 80℃-130℃, preferably 90℃-120℃, more preferably 102℃-110℃.

[0015] Furthermore, in the steam azeotropic solvent removal section, the steam jet shower has a gas velocity of 1 m / s-5 m / s.

[0016] Furthermore, the residence time of the filament bundle in the cooling section is 10-120s, preferably 20-100s, and more preferably 30-90s; the moisture content of the filament bundle is 60%-98%, preferably 70%-95%, and more preferably 80%-90%; the residence time of the filament bundle in the steam azeotropic solvent removal section is 10-300s, preferably 30-200s, and more preferably 45-135s; the moisture content of the filament bundle is 1%-30%, preferably 2%-20%, and more preferably 4%-10%; the residence time of the filament bundle in the constant temperature dehumidification section is 30-400s, preferably 50-240s, and more preferably 60-180s; the moisture content of the filament bundle is less than 2%.

[0017] Furthermore, the heat source of the constant temperature dehumidification section is provided by the high-pressure steam of the steam condensation solvent recovery pipeline and the pipeline network of the steam azeotropic solvent removal section, and the temperature is controlled at 120±5°C by a steam regulating valve.

[0018] Furthermore, the drafting ratio in step 3) is 5-40 times, preferably 10-30 times, and more preferably 18-26 times.

[0019] The good solvent recovery rate in the preparation process of the present invention is above 98%; the prepared finished fine-denier high-strength UHMWPE fiber has a fineness of 0.1-0.7 dtex, a strength of 31-45 cN / dtex, and a modulus of 1200-1700 cN / dtex. Beneficial Effects

[0020] By adopting the steam azeotropic method implemented in the present invention, the solvent of the gel raw yarn in the spinning process is removed. Under the action of flowing steam at different temperatures and pressures, the volatile solvent and steam co-azeotropy the gel filament bundle in the spinning box, thereby quickly removing the water / solvent mixture on the fiber surface. A steam condensation solvent recovery pipeline is set at the steam outlet on the side of the hot box for recovering the solvent. At the same time, the latent heat of the steam condensed water can be used for heat preservation of the lower section of the hot box. Therefore, the purpose of efficient solvent recovery can be achieved under low energy consumption conditions; not only the operating cost of the device is greatly reduced, but also the equipment setting of the device is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a spinneret assembly and a spinning box in an apparatus for preparing fine-denier high-strength UHMWPE fibers according to an embodiment of the present invention.

[0022] Figure 2 Schematic top view of the arrangement of the spinneret assembly in the embodiment.

[0023] Figure 3Schematic diagram of top view of the upper part of the spinning box body in the embodiment.

[0024] In the figure, 1-spinning assembly; 2-cooling section; 3-steam azeotropic solvent removal section; 4-steam condensation solvent recovery pipeline; 5-constant temperature dehumidification section; 6-solvent collection tank; 7-bundling; 8-steam regulating valve; 9-steam transition tank; 11-top view of single-row arrangement of spinneret assembly; 12-top view of matrix arrangement of spinneret assembly; 21-top view of single-row arrangement of fiber bundle channel in cooling section; 22-top view of matrix arrangement of fiber bundle channel in cooling section. Implementation

[0025] The present invention will be described in detail below through examples and drawings. Example

[0026] A device for preparing fine denier high-strength UHMWPE fiber, mainly comprising swelling, extrusion and post-spinning equipment, wherein the innovation is that a distributed spinneret assembly 1 and a vertical spinning box are arranged after the extrusion equipment (see attached Figure 1-3 ); The distributed spinneret assembly 1 includes a plurality of spinnerets having different apertures, arranged in a matrix or single row (see Appendix Figure 2 ); the vertical spinning box includes a spinning cooling section 2, a steam azeotropic solvent removal section 3 and a constant temperature dehumidification section 5 from top to bottom; the steam azeotropic solvent removal section 3 includes a vertical steam inner tube, and the wall of the vertical steam inner tube is provided with a steam spray shower corresponding to the tow channel.

[0027] In the embodiment, the middle of the cooling section 2 is a fiber channel arranged in a single row or matrix, and the periphery is a flow freezing medium channel (see the attached Figure 3 ).

[0028] In the embodiment, the middle of the steam azeotropic solvent removal section 3 is a filament channel arranged in a single row or a matrix. When arranged in a single row, the steam spray shower is placed on one side of the filament channel. When arranged in a matrix, the steam spray shower is placed on one side and the front and rear sides of the filament channel.

[0029] In the embodiment, the vertical steam inner tube of the steam azeotropic solvent removal section 3 is connected to the high-pressure steam network through a steam transition tank 9; the steam outlet of the steam azeotropic solvent removal section 3 is provided with a steam regulating valve 8 and a steam condensation solvent recovery pipeline 4, and the steam condensation solvent recovery pipeline 4 is coiled around the periphery of the filament channel of the constant temperature dehumidification section 6.

[0030] The following embodiments use the above-mentioned equipment to prepare fine denier high-strength UHMWPE fibers. During the preparation process, steam is provided by a high-pressure steam official website and sprayed out through the vertical steam inner tube wall of the steam azeotropic solvent removal section 3; the heat source of the constant temperature dehumidification section 6 is provided by the high-pressure steam of the steam condensation solvent recovery pipeline 4 and the pipe network. Example 1

[0031] 1.25kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 6 million and a degree of entanglement of 0.368 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and then stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entered and passed through the cooling section 2 of the vertical spinning box, and then inside the box The temperature of the cooling medium is set to -10°C. After the tow stays in this section for 60 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere with a temperature of 106°C and a pressure of 135KPa. After staying in this section for 90 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 120 seconds to further reduce the moisture content of the fiber. After the set 22 times of drafting in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by azeotropy enters the solvent collection tank 6 through the steam condensation solvent recovery pipeline 4 for recovery. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 86.64%, 7.21% and 1.33% respectively, and the solvent recovery rate of the spinning process is 98.46%. The dry raw silk is subjected to a three-stage drawing process with a total ratio of 9.5 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single yarn fineness 0.19 dtex, breaking strength 44.12 cN / dtex, modulus 1608 cN / dtex. Example 2

[0032] 1.25kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 5 million and a degree of entanglement of 0.315 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and then stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entered and passed through the cooling section 2 of the vertical spinning box, and then inside the box The temperature of the cooling medium is set to -5°C. After the tow stays in this section for 90 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 102°C and a pressure of 116KPa. After staying in this section for 135 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 180 seconds to further reduce the moisture content of the fiber. After the 18-fold drafting set in the box, the dry raw silk is obtained after the bundle is bundled and dropped. The condensed liquid produced by the azeotropic reaction enters the solvent collection tank 6 for recovery through the steam condensation solvent recovery pipeline 4. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 81.57%, 4.54% and 1.00% respectively, and the solvent recovery rate of the spinning process is 98.78%. The dry raw silk is subjected to a three-stage drawing process with a total ratio of 12 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single fiber fineness 0.27dtex, breaking strength 42.54cN / dtex, modulus 1543cN / dtex. Example 3

[0033] 1.15kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 6.5 million and a degree of entanglement of 0.414 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and back-mixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entering and passing through the cooling section 2 of the vertical spinning box, the box The temperature of the internal cooling medium is set to -15°C. After the tow stays in this section for 30 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 110°C and a pressure of 150KPa. After staying in this section for 45 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 60 seconds to further reduce the moisture content of the fiber. After the 26-fold drafting set in the box, the bundle is bundled and doffed at 7 to obtain dry raw silk. The condensed liquid produced by the azeotropic reaction enters the solvent collection tank 6 for recovery through the steam condensation solvent recovery pipeline 4. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 89.25%, 9.18% and 1.57% respectively. The solvent recovery rate of the spinning process is 98.78%. The dry raw silk is subjected to a three-stage drawing process with a total ratio of 7.5 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single fiber fineness 0.21dtex, breaking strength 43.18cN / dtex, modulus 1578cN / dtex. Example 4

[0034] 1.05kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 5 million and a degree of entanglement of 0.356 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinning assemblies, first entered and passed through the cooling section 2 of the vertical spinning box, and then inside the box The temperature of the cooling medium is set to 0°C. After the tow stays in this section for 120s, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 100°C and a pressure of 100KPa. After staying in this section for 180s, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 240s to further reduce the moisture content of the fiber. After the set 10-fold drafting in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by azeotropy enters the solvent collection tank 6 through the steam condensation solvent recovery pipeline 4 for recovery. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 75.41%, 3.37% and 0.75% respectively. The solvent recovery rate of the spinning process is 99.01%. The dry raw silk is subjected to a three-stage drafting process with a total ratio of 8 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention, and the performance test results thereof are: single yarn fineness 0.56 dtex, breaking strength 32.45 cN / dtex, and modulus 1238 cN / dtex. Example 5

[0035] 1.35kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 4.5 million and a degree of entanglement of 0.298 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and then stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entering and passing through the cooling section of the vertical spinning box, and then entering the box. The temperature of the cooling medium is set to -20°C. After the tow stays in this section for 20 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 115°C and a pressure of 181KPa. After staying in this section for 30 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 40 seconds to further reduce the moisture content of the fiber. After the 28 times of drafting set in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by azeotropy enters the solvent collection tank 6 through the steam condensation solvent recovery pipeline 4 for recovery. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 95.11%, 14.45% and 1.84% respectively, and the solvent recovery rate of the spinning process is 98.07%. The dry raw silk is subjected to a three-stage drafting process with a total ratio of 5.4 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single yarn fineness 0.37dtex, breaking strength 36.28cN / dtex, modulus 1475cN / dtex. Example 6

[0036] 1.15kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 5.5 million and a degree of entanglement of 0.364 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entering and passing through the cooling section 2 of the vertical spinning box, the box The temperature of the internal cooling medium is set to -15°C. After the tow stays in this section for 30 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere with a temperature of 112°C and a pressure of 163KPa. After staying in this section for 45 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 60 seconds to further reduce the moisture content of the fiber. After the 24 times of drafting set in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by the azeotropic reaction enters the solvent collection tank 6 for recovery through the steam condensation solvent recovery pipeline 4. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 93.28%, 12.78% and 1.70% respectively. The solvent recovery rate of the spinning process is 98.18%. The dry raw silk is subjected to a three-stage drafting process with a total ratio of 6.1 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single yarn fineness 0.61dtex, breaking strength 35.56cN / dtex, modulus 1279cN / dtex. Example 7

[0037] 1.05kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 6 million and a degree of entanglement of 0.378 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entered and passed through the cooling section 2 of the vertical spinning box, and then inside the box The temperature of the cooling medium is set to -10°C. After the tow stays in this section for 60 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 118°C and a pressure of 200KPa. After staying in this section for 90 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 120 seconds to further reduce the moisture content of the fiber. After the 24 times of drafting set in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by azeotropy enters the solvent collection tank 6 through the steam condensation solvent recovery pipeline 4 for recovery. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 90.16%, 10.67% and 1.40% respectively, and the solvent recovery rate of the spinning process is 98.45%. The dry raw silk is subjected to a three-stage drafting process with a total ratio of 6.5 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single yarn fineness 0.49 dtex, breaking strength 36.78 cN / dtex, modulus 1429 cN / dtex. Example 8

[0038] 1.45kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 4 million and a degree of entanglement of 0.351 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and then stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entered and passed through the cooling section 2 of the vertical spinning box, and then inside the box The temperature of the cooling medium is set to -5°C. After the tow stays in this section for 90 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 100°C and a pressure of 100KPa. After staying in this section for 135 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 180 seconds to further reduce the moisture content of the fiber. After the 16-fold drafting set in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by the azeotropic reaction enters the solvent collection tank 6 for recovery through the steam condensation solvent recovery pipeline 4. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 82.25%, 5.51% and 1.48% respectively. The solvent recovery rate of the spinning process is 98.20%. The dry raw silk is subjected to a three-stage drawing process with a total ratio of 7.5 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single yarn fineness 0.38dtex, breaking strength 38.18cN / dtex, modulus 1276cN / dtex. Example 9

[0039] 1.45kg of ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 4.5 million and a degree of entanglement of 0.376 was added into a swelling kettle containing 20L of solvent decalin with stirring, heated to 80°C and then gradually heated to 95°C at a rate of 5°C per hour and then stabilized for one hour to complete the preparation of the spinning solution; the spinning solution entered the twin-screw extruder from the homogenizing kettle equipped with a self-circulation for further swelling, dissolution, shearing, degassing and remixing to form a high-viscoelastic gel solution, and then extruded through multiple matrix-type or single-row-arranged spinnerets 1, first entered and passed through the cooling section 2 of the vertical spinning box, and then the spinning solution was extruded into the spinning box. The temperature of the cooling medium is set to -20°C. After the tow stays in this section for 20 seconds, it enters the steam azeotropic solvent removal section 3 of the spinning manifold. The tow is desolventized in a steam atmosphere at a temperature of 125°C and a pressure of 249KPa. After staying in this section for 30 seconds, the tow enters the constant temperature dehumidification section 5 of the spinning manifold. It stays in the box with a set temperature of 120±5°C for 40 seconds to further reduce the moisture content of the fiber. After the 24 times of drafting set in the box, the bundle is bundled 7 and then dropped to obtain dry raw silk. The condensed liquid produced by azeotropy enters the solvent collection tank 6 through the steam condensation solvent recovery pipeline 4 for recovery. After the device is stably operated, the moisture content of the tow at the end of the upper cooling section of the spinning manifold, the middle steam azeotropic solvent removal section and the lower constant temperature dehumidification section is sampled and analyzed, and the test results are 96.74%, 15.68% and 1.67% respectively. The solvent recovery rate of the spinning process is 98.27%. The dry raw silk is subjected to a three-stage drafting process with a total ratio of 5.5 times in the post-spinning equipment to prepare the fine denier high-strength ultra-high molecular weight polyethylene fiber obtained by the implementation of the present invention. The performance test results are: single yarn fineness 0.29dtex, breaking strength 40.16cN / dtex, modulus 1315cN / dtex.

[0040] By adopting the steam azeotropic method implemented in the present invention, the solvent of the gel raw yarn in the spinning process is removed. Under the action of flowing steam at different temperatures and pressures, the volatile solvent and steam co-azeotropy the gel filament bundle in the spinning box, thereby quickly removing the water / solvent mixture on the fiber surface. A steam recovery pipeline is arranged at the steam outlet on the side of the hot box to recover the solvent. At the same time, the latent heat of the steam condensed water can be used for heat preservation of the lower section of the hot box. Therefore, the purpose of efficient solvent recovery can be achieved under low energy consumption conditions. This not only greatly reduces the operating cost of the device, but also greatly reduces the equipment settings of the device.

Claims

1. A device for preparing fine denier high-strength UHMWPE fiber, including swelling, extrusion and post-spinning equipment, characterized in that A distributed spinneret assembly and a vertical spinning box are arranged behind the extrusion equipment; the distributed spinneret assembly includes a plurality of spinnerets with different apertures, which are arranged in a matrix or single row; the vertical spinning box includes a spinning cooling section, a steam azeotropic solvent removal section and a constant temperature dehumidification section from top to bottom; the steam azeotropic solvent removal section includes a vertical steam inner tube, and a steam spray shower is provided on the wall of the vertical steam inner tube corresponding to the filament bundle channel.

2. The device according to claim 1, characterized in that The middle of the cooling section is a filament channel arranged in a single row or matrix, and the periphery is a flowing freezing medium channel.

3. The device according to claim 1, characterized in that The middle of the steam azeotropic solvent removal section is a filament channel arranged in a single row, and a steam jet shower is arranged on one side of the filament channel.

4. The device according to claim 1, characterized in that The middle of the steam azeotropic solvent removal section is a fiber channel arranged in a matrix shape, and steam spray showers are placed on one side and the front and rear sides of the fiber channel.

5. The device according to claim 1, characterized in that The vertical steam inner pipe of the steam azeotropic solvent removal section is connected to the high-pressure steam network through a steam transition tank; the steam outlet of the steam azeotropic solvent removal section is provided with a steam regulating valve and a steam condensation solvent recovery pipeline.

6. The device according to claim 5, characterized in that The steam condensation solvent recovery pipeline is coiled around the periphery of the constant temperature dehumidification section tow channel.

7. A method for preparing fine denier high-strength UHMWPE fiber, characterized in that The device according to any one of claims 1 to 6 comprises the following steps: Adding low entanglement UHMWPE resin and good solvent in a proportion into a swelling kettle with stirring, heating and raising the temperature to obtain a spinning solution; The spinning solution is formed into a high-viscoelastic gel solution through a twin-screw extruder, which is extruded by a distributed spinneret assembly and then enters a vertical spinning box to form gel filaments. The gel precursor first passes through a cooling section in a vertical spinning box to form frozen gel precursor; then passes through a steam azeotropic solvent removal section to form frozen gel precursor with a certain humidity; finally passes through a constant temperature dehumidification section and is stretched at a set stretching ratio in the box to obtain dry precursor; The dry raw silk is further stretched at a stretching ratio set by the post-spinning equipment to produce fine denier and high-strength UHMWPE fiber.

8. The method according to claim 7, characterized in that In the step 1), the viscosity average molecular weight of the UHMWPE resin is 4-6.5 million, and the degree of entanglement is 0.1-0.6; the good solvent is selected from decahydronaphthalene, tetrahydronaphthalene, and xylene; the ratio of the UHMWPE resin to the good solvent is (5:94)-(12:88); after heating to 80°C, the temperature is gradually increased at a rate of 5°C per hour to 95°C and then stabilized for one hour.

9. The method according to claim 7, characterized in that The temperature control range of the cooling section is -30°C-10°C, preferably -20°C-0°C, and more preferably -15°C--5°C.

10. The method according to claim 7, characterized in that In the steam azeotropic solvent removal section, the steam quality entering the spinning manifold is 90, the steam pressure is 50KPa-300KPa, preferably 80KPa-200KPa, more preferably 100KPa-160KPa; the temperature is 80℃-130℃, preferably 90℃-120℃, more preferably 102℃-110℃.

11. The method according to claim 7, characterized in that In the steam azeotropic solvent removal section, the steam jet shower has a gas velocity of 1 m / s-5 m / s.

12. The method according to claim 7, characterized in that The residence time of the filament bundle in the cooling section is 10-120s, preferably 20-100s, and more preferably 30-90s; the moisture content of the filament bundle is 60%-98%, preferably 70%-95%, and more preferably 80%-90%; the residence time of the filament bundle in the steam azeotropic solvent removal section is 10-300s, preferably 30-200s, and more preferably 45-135s; the moisture content of the filament bundle is 1%-30%, preferably 2%-20%, and more preferably 4%-10%; the residence time of the filament bundle in the constant temperature dehumidification section is 30-400s, preferably 50-240s, and more preferably 60-180s; the moisture content of the filament bundle is less than 2%.

13. The method according to claim 7, characterized in that The heat source of the constant temperature dehumidification section is provided by the steam condensation solvent recovery pipeline and high-pressure steam of the pipeline network in the steam azeotropic solvent removal section, and the temperature is controlled at 120±5℃ by a steam regulating valve.

14. The method according to claim 7, characterized in that The drafting ratio in step 3) is 5-40 times, preferably 10-30 times, and more preferably 18-26 times.

15. The method according to any one of claims 7 to 14, characterized in that The good solvent recovery rate in the preparation process is above 98%; the finished fine-denier high-strength UHMWPE fiber has a fineness of 0.1-0.7 dtex, a strength of 31-45 cN / dtex, and a modulus of 1200-1700 cN / dtex.

Images