WO2021097961A1

WO2021097961A1 - Spinneret component for para-aramid spinning

Info

Publication number: WO2021097961A1
Application number: PCT/CN2019/124244
Authority: WO
Inventors: 庹新林; 赵海林
Original assignee: 中芳特纤股份有限公司; 清华大学
Priority date: 2019-11-22
Filing date: 2019-12-10
Publication date: 2021-05-27
Also published as: CN110685022B; CN110685022A

Abstract

A spinneret component for para-aramid spinning, and which relates to the technical field of spinning device. The interior of an upper component (1) is provided with a middle flow passage (105) and a hollow cavity (110); a bottom plate (303) of which the inner side is a curved surface, the outer side is a flat surface, a middle part is thick and a surrounding part is thin is provided with a spinning hole (304) which comprises a conical part (305) and cylindrical parts (306); and the upper component (1) is embedded in a first hole (201) to tightly fit to a connecting plate (301) of a spinneret (3) in a lower component (2). The bottom plate (303) structure helps to disperse the pressure, so the deformation resistance of the spinneret (3) is enhanced, and the middle spinning hole (304) is extended to reduce the flow speed of the spinning solution at the middle; the upper component (1) structure improves the flow conditions of the spinning solution in the spinneret component, increases the flow speed of the spinning solution at the edge; and the cylindrical parts (306) are completely the same to guarantee the same expansion ratio of outlets which spray the materials so as to spin uniform fibers.

Description

Spinneret assembly for para-aramid spinning

Technical field

The invention relates to the technical field of spinning devices, in particular to a spinneret assembly for para-aramid spinning.

Background technique

Para-aramid fiber is a new type of high-tech synthetic fiber with super high strength, high modulus, high temperature resistance, acid and alkali resistance, light weight, insulation, aging resistance, long life cycle and other excellent properties, which are widely used in composite materials , Bulletproof products, building materials, special protective clothing, electronic equipment and other fields.

The dry jet wet spinning method is a spinning process. After the spinning dope is sprayed through the spinning device, it passes through the air layer and then enters the coagulation bath; this method is suitable for spinning solutions with higher concentration and higher viscosity; in addition, , The spinneret assembly is the core component of the spinning device, which has a decisive influence on the quality of the fiber.

However, poly-p-phenylene terephthalamide is insoluble. The existing para-aramid fiber processing uses poly-p-phenylene terephthalamide-concentrated sulfuric acid solution for spinning. In order to ensure the strength of the fiber tow, It will increase the concentration of the spinning solution. Since the polyparaphenylene terephthalamide-concentrated sulfuric acid solution is a non-Newtonian fluid, the viscosity of the spinning solution increases as the concentration increases. Para-aramid fibers are mostly produced by dry jet wet spinning.

The spray pressure required for dry jet wet spinning is 10-40 bar, which is relatively large. When the jetting pressure is too small, the spinneret holes on the edge of the spinneret will produce thin filaments or even not easy to eject. The subsequent drawing tow is easy to break. In order to ensure the quality of spinning, a larger jetting pressure is required. The thickness of the spinneret is only a few millimeters. The high spray pressure can easily cause the spinneret to bulge, deform and break, and the spinneret is expensive; when the spinneret is deformed, the ejected tow is uneven and the quality is poor. Increasing the thickness of the spinneret can alleviate the above-mentioned problems, but the existing technology has technical difficulties in manufacturing high-thickness spinnerets.

When the spinning solution passes through the spinneret assembly, the flow rate of the spinning solution in the flow channel shows a certain law. When the temperature is 60-80℃, the concentration is about 20%, and the spinning speed is 200-2000m/min, the resistance of the inner wall of the pipe will affect the wall slippage of the long-chain polymer in the spinning solution, and the middle of the pipe The flow rate is larger, and the flow rate is slower near the pipe wall. The sprayed tow is uneven, the tow is thick in the middle of the spinneret, and the tow is thin at the edge.

The patent number is CN 1973065B, and the Chinese patent titled "Spinneret assembly, fiber bundle manufacturing device and manufacturing method for dry and wet spinning" is to solve the problem of the spinning hole formed by the spinning hole located on the center side of the spinneret surface in porous spinning. The problem of uneven fineness between the single fiber and the single fiber formed by the spinning hole located on the outer peripheral side of the spinneret surface, and the technical solution adopted is a spinneret assembly for dry and wet spinning, including: a spinneret frame Body: a spinning dope flow path, which is provided inside the spinneret housing; a spinning dope supply port, which is provided in the spinneret housing and supplies spinning dope to the spinning dope flow path; a spinneret, Installed in the spinneret frame, a plurality of spinning holes for ejecting the spinning dope of the spinning dope flow path are arranged at intervals; the outer surface of the spinneret faces the liquid surface of the coagulation liquid through the gas phase The number of the spinning holes is 6000 or more, and the aspect ratio Ra of the spinning hole arrangement of the spinning holes is 2.5 or more. The main idea of the technical solution is to provide a spinning technology that can maintain approximately the same distance between the spinneret surface and the liquid surface of the coagulation liquid, that is, the gap between the center side and the outer peripheral side of the spinneret during spinning, The main purpose is to ensure the consistency of the length of the spinning solution flow channel; it is not designed in conjunction with the spinneret deformation and flow rate changes caused by factors such as jet pressure, high-speed spinning, and pipeline resistance.

Summary of the invention

The invention provides a spinneret assembly for para-aramid spinning. The flow channel in the upper assembly, the spinneret bottom plate and the spinneret holes are structurally designed, and a heating structure is added in the assembly to improve the spinning solution The flow in the spinneret assembly solves the above problems.

A spinneret assembly for para-aramid spinning, comprising: an upper assembly, a lower assembly and a spinneret; the upper assembly has an upper convex column above the upper assembly and a lower convex column below the upper assembly; there is a spinning solution inside the upper assembly The middle runner flowing through and the hollow cavity for heat exchange with the heating medium, the hollow cavity is located at the periphery of the middle runner; the middle runner inside the upper assembly runs through the upper convex column and the lower convex column; the spinning solution passes through the middle runner Enter the spinneret and then spray;

The spinneret includes a connecting plate, a side wall and a bottom plate; the connecting plate and the side wall are connected by an arc-shaped first transition surface, and the chamfered transitional connection between the side wall and the bottom plate enhances the ability of the spinneret to resist deformation. It is not easy to crack; the bottom plate is a curved surface with a radius of curvature in the range of 1800-2400mm on the inside and a thin circular plate with a middle thickness on the outside and a flat surface. The curved surface of the bottom plate is the position where the middle runner of the upper component meets, and the curved surface forms an arch The structure disperses pressure, enhances the ability to resist deformation, and improves or avoids the phenomenon of bulging deformation of the spinneret due to high injection pressure;

A number of spinneret holes are set on the bottom plate; the spinneret holes are through holes, which are divided into a circular cone part and a cylindrical part. The cylindrical part is close to the outside. The cylindrical part of each spinneret hole is exactly the same. The ratio of the length of a single cylindrical part to the aperture is 2-5, the pore diameter of the cylindrical part is 1-100μm; the middle of the bottom plate is thicker than the surroundings, and the spinneret flow channel in the middle is long. The resistance of the pipe balances the concentrated pressure that appears at the high flow rate of the spinning solution, and slows down the spinning solution in the middle. Flow rate

There is a hollow cavity inside the upper assembly, and the water inlet pipe and the water outlet pipe are respectively connected to the hollow cavity; during spinning, the spinning solution with a certain temperature enters the unheated spinneret assembly, and the temperature difference will cause the viscosity of the spinning solution to increase instantaneously , Its own fluidity becomes worse, which is unfavorable to spinning processing; at the same time, the pressure difference on the spinneret is increased; hot water and other media are passed into the upper assembly for heating to eliminate the adverse effects of temperature difference; moreover, in the middle runner Heating on the outer side wall of the tube can increase the flow rate of the spinning solution at the pipe wall, improve the spinning situation at the edge of the spinneret, and facilitate uniform spinning;

There are a first hole and a second hole in the middle of the lower assembly. The hole diameter of the second hole is smaller than the hole diameter of the first hole. The periphery of the second hole is an annular clamping table; the spinneret is embedded in the second hole through the connecting plate and the annular clamping table Overlap mounted on the lower assembly, the spinneret and the second hole are in interference fit; the upper assembly is embedded in the first hole and closely fits with the spinneret's connecting plate; the upper assembly and the first hole are in interference fit .

Further, the upper surface of the bottom plate is a second transition surface, and the second transition surface is a spherical surface. The arc-shaped smooth transition without obstruction realizes the smooth flow of the spinning solution.

Further, the ratio of the length of the cylindrical part to the hole diameter is 3-4. The poly-p-phenylene terephthalamide-concentrated sulfuric acid solution is a non-Newtonian fluid and has outlet expansion. The larger the aspect ratio at the spinneret hole, the smaller the outlet expansion ratio; and an excessively large aspect ratio is not conducive to Spinning. The cylindrical part of each spinneret hole remains the same, and a certain aspect ratio is set to ensure that the outlet expansion ratio of the sprayed material is consistent.

Further, the diameter of the bottom plate is 10-100 cm, and the hole diameter of the cylindrical part is 40-70 μm. Mainly suitable for high-speed spinning of para-aramid. The cylindrical part of the spinneret hole needs to be moderate. If the hole diameter is too large, the strength of the ejected fiber is low, and it is easy to break. If the hole diameter is too small, it will be difficult to remove the cylindrical part once blockage occurs. For the residues in the round table, it is less difficult to remove. For the design of the specific size of the spinneret and the spinneret hole, various spinning process conditions need to be considered. When the concentration of the spinning solution, the spinning temperature or the spinning speed are changed, the requirements for the specific size of the spinneret and the spinneret are different.

Further, the intermediate flow channel includes a first flow channel, a second flow channel and a third flow channel. The inner diameter of the first flow channel in the upper boss is larger than the inner diameter of the second flow channel, and the second flow channel is connected to each other through a wide-angle flaring. Diffusion-type, hemispherical third runner. The spinning solution entering the upper assembly can be uniformly dispersed on the entire spinneret after being buffered once at the wide-angle flaring and hemispherical third flow channel.

Further, a partition is arranged in the hollow cavity to divide the hollow cavity into a first area and a second area; the first area is between the outer wall of the middle flow channel and the partition, and the second area is between the partition and the outer wall of the hollow cavity. Between; the water inlet pipe is connected to the partition plate to directly communicate with the first area, and the water outlet pipe is connected to the outer wall of the hollow cavity to communicate with the second area. When the temperature of the spinning solution is 80°C, hot water of 80-90°C can be introduced into the hollow cavity. The hot water directly reaches the first zone, heats the inner wall, and then flows into the second zone and flows out from the outlet pipe.

Furthermore, the radius of curvature of the inner curved surface of the bottom plate is 2000-2200mm. Match the size of the bottom plate to keep the bottom plate with a certain arched structure.

Compared with the prior art, in the present invention, the arched structure of the bottom plate of the spinneret is beneficial to disperse the pressure, the spinneret’s ability to resist deformation is enhanced, and the middle spinneret hole is lengthened to balance the high flow rate of the spinning solution with the resistance of the pipe. The concentrated pressure slows down the flow rate of the spinning solution in the middle; the cylindrical part of each spinneret hole is exactly the same, which ensures the consistency of the outlet expansion ratio of the ejected material, and can spin fiber with uniform thickness; the upper component has multiple flow channels The combined, hemispherical outlet design facilitates the diffusion and uniform flow of the spinning solution and relieves the pressure of the intermediate spinning solution; there is a heating structure in the upper assembly, which can increase the flow rate of the spinning solution at the pipe wall and improve the spray at the edge of the spinneret. The situation of the thread exiting from the thread hole is conducive to uniform thread exit.

Description of the drawings

The drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the exemplary embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention.

Figure 1 is a schematic diagram of a spinneret assembly for para-aramid spinning;

Figure 2 is an exploded view of a spinneret assembly for para-aramid spinning;

Figure 3 is a front view of a spinneret assembly for para-aramid spinning;

Figure 4 is a sectional view of A-A in Figure 3;

Figure 5 is a left view of the upper assembly of a spinneret assembly for para-aramid spinning;

Figure 6 is a cross-sectional view of C-C in Figure 5;

Figure 7 is a front view of a spinneret in a spinneret assembly for para-aramid spinning;

Fig. 8 is a cross-sectional view of B-B in Fig. 7.

Description of reference signs:

1. Upper assembly, 2. Lower assembly, 3. Spinneret, 4. Mounting hole;

101. Upper convex column, 102, lower convex column, 103, inlet pipe, 104, outlet pipe, 105, middle runner, 106, first runner, 107, second runner, 108, third runner, 109, Flaring, 110, hollow cavity, 111, partition, 112, first zone, 113 second zone;

201, the first hole, 202, the second hole, 203, the ring card table;

301, connecting plate, 302, side wall, 303, bottom plate, 304, spin hole, 305, truncated cone part, 306, cylindrical part, 307, first transition surface, 308, second transition surface.

Detailed ways

The specific implementation of the present invention will be described below with reference to the drawings and embodiments:

It should be noted that the structure, ratio, size, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification for the understanding and reading of those familiar with this technology, and are not intended to limit the implementation of the present invention. The limiting conditions, any structural modification, proportional relationship, change or size adjustment, shall fall within the scope of the technical content disclosed in the present invention without affecting the effects and objectives that can be achieved by the present invention In the range. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for ease of description, not to limit the text. The scope of implementation of the invention, the change or adjustment of its relative relationship, without substantial changes to the technical content, shall also be regarded as the scope of implementation of the invention.

Figure 1 and Figure 4, a spinneret assembly for para-aramid spinning, including: upper assembly 1, lower assembly 2 and spinneret 3; inside the upper assembly 1 there is an intermediate flow through which the spinning solution flows The channel 105 exchanges heat with the hollow cavity 110 for the heat supply medium. The hollow cavity 110 is located at the periphery of the middle flow channel 105; there are a plurality of spinneret holes 304 on the bottom plate 303, which is thick and thin in the middle.

Figure 5-6, the upper component 1 has an upper convex column 101 above and a lower convex column 102 below; the middle runner 105 inside the upper component 1 penetrates the upper convex column 101 and the lower convex column 102; the middle runner 105 includes the first flow Channel 106, second flow channel 107 and third flow channel 108, the inner diameter of the first flow channel 106 in the upper boss 101 is larger than the inner diameter of the second flow channel 107, and the second flow channel 107 is connected to each other by a wide-angle flaring 109 A downwardly divergent hemispherical third runner 108;

The upper assembly 1 has a hollow cavity 110 inside, and the water inlet pipe 103 and the water outlet pipe 104 are respectively connected to the hollow cavity 110; the hollow cavity 110 is provided with a partition 111 to divide the hollow cavity 110 into a first zone 112 and a second zone 113; A zone 112 is between the outer wall of the intermediate flow channel 105 and the partition 111, and the second zone 113 is between the partition 111 and the outer wall of the hollow cavity 110; the water inlet pipe 103 is connected to the partition 111 and directly communicates with the first zone 112, the outlet pipe 104 is connected to the outer wall of the hollow cavity 110 to communicate with the second area 113.

A plurality of mounting holes 4 are respectively provided on the upper assembly 1 and the lower assembly 2 to facilitate the installation of the spinneret assembly in the spinning device.

Figure 7-8, the spinneret 3 includes a connecting plate 301, a side wall 302 and a bottom plate 303. The connecting plate 301 and the side wall 302 are connected by an arc-shaped first transition surface 307, and the side wall 302 and the bottom plate 303 are chamfered. Connect to enhance the ability of the spinneret 3 to resist deformation, and the spinneret is not easy to crack; the bottom plate 303 is a curved surface with a radius of curvature in the range of 1800-2400mm on the inside and a flat circular plate with a middle thickness and a thin circumference on the outside. The radius of curvature is preferably 2000-2200 mm, which matches the size of the bottom plate 303 to maintain the bottom plate 303 to have a certain arched structure.

The bottom plate 303 is provided with a plurality of spinneret holes 304; the spinneret hole 304 is a through hole, divided into a circular truncated portion 305 and a cylindrical portion 306, the cylindrical portion 306 is close to the outside, the cylindrical portion 306 of each spinneret hole 304 is exactly the same, a single cylinder The ratio of the length to the aperture of the part 306 is 2-5, and the aperture of the cylindrical part 306 is 1-100 μm; preferably, the ratio of the length to the aperture of a single cylindrical part 306 is 3-4, and the aperture of the cylindrical part 306 is 40-70 μm. . It is mainly suitable for high-speed spinning of para-aramid fiber. The cylindrical part 306 in the spinneret hole 304 needs to be moderate. If the hole diameter is too large, the strength of the ejected fiber is low, and it is easy to break. If the hole diameter is too small, it will be difficult to remove once blockage occurs. For the residue in the cylindrical part 306, the truncated part 305 is less difficult to remove.

The upper surface of the bottom plate 303 is a second transition surface 308, and the second transition surface 308 is a spherical surface.

In FIG. 2, there are a first hole 201 and a second hole 202 in the middle of the lower assembly 2. The hole diameter of the second hole 202 is smaller than the hole diameter of the first hole 201. The second hole 202 is surrounded by a ring chuck 203.

Figure 2-4, the spinneret 3 is embedded in the second hole 202 and is mounted on the lower assembly 2 through the connecting plate 301 and the annular clamping table 203. The spinneret 3 and the second hole 202 are in an interference fit; the upper assembly 1 is embedded in the first hole 201 and closely fits with the connecting plate 301 of the spinneret 3; the upper component 1 and the first hole 201 are in an interference fit.

Example: The diameter of the bottom plate 303 is 80 cm, the diameter of the cylindrical part 306 is 50 μm, the length of the cylindrical part 306 is 200 μm, and the distance between two adjacent spinneret holes 304 is 2 mm. The number is 960. The spinning speed is set to 1200 m/min. During spinning, the temperature of the spinning solution is 80°C, and 85°C hot water is passed into the hollow cavity 110. The spun fiber tow has 960 monofilaments, the monofilament size is 1.2dtex, and the fluctuation range is between 1.18-1.22dtex, which realizes uniform spinning under high-speed conditions.

Many other changes and modifications can be made without departing from the concept and scope of the present invention. It should be understood that the present invention is not limited to specific embodiments, and the scope of the present invention is defined by the appended claims.

Claims

A spinneret assembly for para-aramid spinning, characterized in that:

Including: upper assembly (1), lower assembly (2) and spinneret (3);

Inside the upper assembly (1) there is an intermediate runner (105) for the spinning solution to flow through and a hollow cavity (110) for heat exchange for the heating medium, and the hollow cavity (110) is located at the periphery of the intermediate runner (105);

The spinneret (3) includes a connecting plate (301), a side wall (302) and a bottom plate (303); the bottom plate (303) is a curved surface with a radius of curvature in the range of 1800-2400mm on the inside and a flat surface with a middle thickness and a thin circumference on the outside. The circular plate, the bottom plate (303) is provided with a plurality of spinneret holes (304); the spinneret holes (304) are through holes, divided into a circular truncated part (305) and a cylindrical part (306), the cylindrical part (306) is close to the outside, each The cylindrical part (306) of the spinneret hole (304) is exactly the same, the ratio of the length of the single cylindrical part (306) to the hole diameter is 2-5, and the hole diameter of the cylindrical part (306) is 1-100μm; the connecting plate (301) ) And the side wall (302) are connected by an arc-shaped first transition surface (307);

There are a first hole (201) and a second hole (202) in the middle of the lower component (2). The hole diameter of the second hole (202) is smaller than the hole diameter of the first hole (201), and the periphery of the second hole (202) is annular Card station (203);

The spinneret (3) is embedded in the second hole (202) and is installed on the lower assembly (2) through the connecting plate (301) and the annular clamping table (203). The spinneret (3) and the second hole (202) are overlapped and installed on the lower assembly (2). ) Is an interference fit; the upper component (1) is embedded in the first hole (201) and closely fits with the connecting plate (301) of the spinneret (3); between the upper component (1) and the first hole (201) It is an interference fit.
The spinneret assembly for para-aramid spinning according to claim 1, wherein the upper assembly (1) has an upper convex column (101) above and a lower convex column (102) below; The middle flow channel (105) penetrates the upper convex column (101) and the lower convex column (102); the water inlet pipe (103) and the water outlet pipe (104) are respectively connected with the hollow cavity (110).
The spinneret assembly for para-aramid spinning according to claim 1, wherein the upper surface of the bottom plate (303) is a second transition surface (308), and the second transition surface (308) is Spherical.
The spinneret assembly for para-aramid spinning according to claim 1, wherein the ratio of the length of the cylindrical portion (306) to the aperture is 3-4.
The spinneret assembly for para-aramid spinning according to claim 1, wherein the diameter of the bottom plate (303) is 10-100 cm, and the hole diameter of the cylindrical part (306) is 40-70 μm.
The spinneret assembly for para-aramid spinning according to claim 1, wherein the middle runner (105) comprises a first runner (106), a second runner (107) and a third runner (107). Runner (108), the inner diameter of the first runner (106) in the upper boss (101) is larger than the inner diameter of the second runner (107), and the second runner (107) is connected by a wide-angle flaring (109) A downwardly diffused hemispherical third flow channel (108).
The spinneret assembly for para-aramid spinning according to claim 1, wherein a partition (111) is arranged in the hollow cavity (110) to divide the hollow cavity (110) into the first zone (112) and the second area (113); the first area (112) is between the outer wall of the middle flow channel (105) and the partition (111), and the second area (113) is between the partition (111) and Between the outer walls of the hollow cavity (110); the inlet pipe (103) is connected to the partition (111) to directly communicate with the first zone (112), and the outlet pipe (104) is connected to the outer wall of the hollow cavity (110) to communicate with the second District (113).
The spinneret assembly for para-aramid spinning according to claim 1, wherein the radius of curvature of the inner curved surface of the bottom plate (303) is 2000-2200mm.