A method for producing high-mold low-shrinkage filaments

Abstract

The present invention relates to a method for producing high modulus and low shrinkage filaments. The filaments extruded through a spinneret are sequentially pre-cooled in a slow cooling zone and a windless zone, and then enter a cooling zone for cooling and forming to obtain high modulus and low shrinkage filaments. The cooling zone includes a connected cooling zone A and a cooling zone B from top to bottom, and a cylindrical duct C connected below the cooling zone B. The cooling zone A is a cylindrical air duct with the air outlet located inside, and the blowing direction is perpendicular to the running direction of the filament bundle. The cooling zone B is a cylindrical air duct with the air outlet located at the lower end, and the blowing direction is parallel to the running direction of the filament bundle. In the method for producing high modulus and low shrinkage filaments of the present invention, a ring blowing cooling zone B is added, and blowing vertically downward can form a similar "vacuum pumping" effect, enabling the hot air in the cooling zone A to flow downward, facilitating the discharge of the hot air, and reducing the influence of the hot air on the nascent filaments.

Description

Technical Field

[0001] The present invention belongs to the technical field of spinning and relates to a production method of high-modulus and low-shrinkage filaments. Background Art

[0002] High-modulus and low-shrinkage filaments for industrial use are mainly used for tire cord, which is the skeleton material of automobile tires. They need to have high strength and good dimensional stability. Their physical properties require high strength, high modulus, and low dry heat shrinkage, and the dimensional stability is affected by the elongation at a specified load and the dry heat shrinkage performance. The literature ("Development of high-modulus and low-shrinkage polyester industrial filaments. Synthetic Fiber Industry, 2013, 36(1): 67-69.") records that in order to make the polyester industrial filaments reach a higher modulus, the production process needs to have a higher spinning speed. In order to prevent the undrawn filaments from crystallizing rapidly in the rapid cooling zone, hot air above 40°C is generally used for cooling in the production of high-modulus and low-shrinkage products. At the same time, multi-hole filaments are required to reduce the fineness of single filaments, so that the filament bundle is cooled evenly and the "skin-core" structure is avoided. In the existing production process, the density of hot air is relatively lower than that of the external ambient air, and the hot air is not easily discharged. The fluidity of the hot air cooling air becomes poor, which affects the cooling of the undrawn fibers. At the same time, since the hot air is not easily discharged downward, it will move upward to the spinneret plate surface, affecting the formation of the nascent fiber. The nascent filaments are prone to form bends and stick to the plate, resulting in poor spinnability and affecting the improvement of the dimensional stability of high-modulus and low-shrinkage products.

[0003] Therefore, it is of great significance to develop a production method of high-modulus and low-shrinkage to solve the problem of poor fluidity of the hot air in the cooling air in the existing technology. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present invention provides a production method of high-modulus and low-shrinkage filaments;

[0005] To achieve the above object, the solution adopted by the present invention is as follows:

[0006] A production method of high-modulus and low-shrinkage filaments, in which the filaments extruded from the spinneret plate are sequentially pre-cooled in a slow-cooling zone and a windless zone and then enter a cooling zone for cooling and forming to obtain high-modulus and low-shrinkage filaments;

[0007] The cooling zone includes a cooling zone A and a cooling zone B connected from top to bottom and a cylindrical duct C connected below the cooling zone B;

[0008] The cooling zone A is a cylindrical air duct with an air outlet on the inner side, blowing air from the outside to the inside, and the blowing direction is perpendicular to the running direction of the filament bundle;

[0009] The cooling zone B is a cylindrical air duct with an air outlet at the lower end, blowing air from top to bottom, and the blowing direction is parallel to the running direction of the filament bundle;

[0010] The blowing air temperature in cooling zone A is 5 - 15°C higher than the ambient temperature, being 40 - 50°C, and the blowing air temperature in cooling zone B is 10 - 15°C lower than the ambient temperature;

[0011] The inner diameter of cooling zone A is larger than that of cooling zone B, and the inner diameter of cooling zone A is smaller than the inner diameter of cylindrical passage C.

[0012] As a preferred technical solution:

[0013] For a high modulus low shrinkage filament production method as described above, the ambient temperature is 35 - 40°C, the air supply temperature of the air conditioner in the filament production environment is about 25°C, but due to many heating devices in the production environment and the melt carrying the heat of the high - temperature melt, the actual production environment temperature (room temperature) is 35 - 40°C.

[0014] For a high modulus low shrinkage filament production method as described above, an annular blowing filter element is arranged inside cooling zone A, and a sleeve I with a diameter larger than the annular blowing filter element and coaxial with the annular blowing filter element is arranged outside cooling zone A. An annular cavity I is formed between the annular blowing filter element and the sleeve I, and the annular cavity I is used for the cooling air to enter. The annular cavity I is communicated and sealed with the outside. During operation, the cooling air enters through the air inlet pipe and fills the annular cavity I, and then penetrates through the annular blowing filter element to cool the filament passing through the center of the annular blowing filter element.

[0015] For a high modulus low shrinkage filament production method as described above, the distance between the inner wall of the sleeve I and the outer wall of the annular blowing filter element (i.e., the width of the annular cavity I) is 1 - 2 cm.

[0016] For a high modulus low shrinkage filament production method as described above, a cylindrical pipe is arranged inside cooling zone B, and a sleeve II with a diameter larger than the cylindrical pipe and coaxial with the cylindrical pipe is arranged outside cooling zone B. An annular cavity II is formed between the cylindrical pipe and the sleeve II, and the annular cavity II is used for the cooling air to enter, and the top of the annular cavity II is sealed; the distance between the inner wall of the sleeve II and the outer wall of the cylindrical pipe (i.e., the width of the annular cavity II) is 1 - 2 cm; the bottom of the sleeve I is fixedly connected to the top of the sleeve II; during operation, the cooling air enters through the air inlet pipe and fills the annular cavity II, and then enters the passage through the bottom of the annular cavity II; in addition, it is further preferred that the sleeve I and the sleeve II are integrally formed parts.

[0017] For a high modulus low shrinkage filament production method as described above, the inner diameter of the annular blowing filter element in cooling zone A is 270 - 280 mm, the inner diameter of the cylindrical pipe in cooling zone B is 220 - 230 mm, and the inner diameter of the cylindrical passage C is 310 - 320 mm.

[0018] A method for producing high modulus and low shrinkage yarn as described above, the height of the slow cooling zone is 95 - 105 mm, the height of the windless zone is 45 - 55 mm, the height of cooling zone A is 440 - 460 mm, the height of cooling zone B is 390 - 410 mm, and the height of the cylindrical channel C is 690 - 710 mm; The principle of the high modulus and low shrinkage production process is high-speed spinning and extremely rapid cooling to obtain products with high modulus and high dimensional stability. Therefore, the slow cooling zone and the windless zone become smaller, and the degree of extreme cold is enhanced, which can improve the modulus and dimensional stability of the products.

[0019] A method for producing high modulus and low shrinkage yarn as described above, the fineness of the monofilament of the high modulus and low shrinkage yarn is 4.71 - 5.65 dtex, and the number of fibers is 200 - 240 f.

[0020] A method for producing high modulus and low shrinkage yarn as described above, the spinning speed (i.e., the speed of the first roller) is 3000 - 3400 m / min, and the winding speed is 5800 - 6200 m / min. After cooling and forming, winding is carried out. In the prior art for producing high strength and low shrinkage yarn, the speed of the first roller is 2600 - 3000 m / min, and the winding speed is 5200 - 5400 m / min. In the prior art for producing high modulus and low shrinkage yarn, the speed of the first roller and the winding speed can also be higher, but after increasing the speed, the number of broken ends increases, and the downgrading of the appearance of the hairiness also increases; After the improvement of the cooling in the present invention, the number of holes can be fewer, and the fineness of the monofilament can be larger, so the anti-drawing performance of the filament bundle is better, and it can be produced with a higher speed and draw ratio. A higher speed can improve the modulus and dimensional stability of the product, and a higher draw ratio can improve the strength of the product.

[0021] A method for producing high modulus and low shrinkage yarn as described above, the initial modulus of the high modulus and low shrinkage yarn is 105 - 110 cN / dtex, and the dimensional stability is 7 - 8.5%.

[0022] Taking the 1000D product of the prior art as an example, the actual fineness is 1130 dtex, the number of holes is 300 - 360, and the fineness of the monofilament is 3.14 - 3.77 dtex. By the method of the present invention, increasing the cooling air flow momentum to solve the problem of uneven cooling of the monofilament due to too large fineness of the monofilament, the number of holes can be improved to 200 - 240, the actual fineness remains unchanged, and the fineness of the monofilament becomes 4.71 - 5.65 dtex. With the increase of the fineness of the monofilament, there is a higher space for speed increase in the production process of filament yarn, that is, under the condition of maintaining the spinning condition and appearance, the spinning speed and draw ratio can be better improved. When the production process remains unchanged and only the number of holes is reduced, the modulus and dimensional stability of the product basically do not change. The present invention improves the cooling air efficiency to solve the problem of uneven cooling after the reduction of the hole speed, thereby increasing the spinning speed, improving the modulus and dimensional stability of the product.

[0023] The principle of the present invention is:

[0024] In the cooling zone B, the low-temperature cooling air is at 20-25°C, and the blowing direction is parallel to the running direction of the tow. One of the purposes is to cool the tow for the second time to make the cooling effect inside and outside the tow uniform; the second purpose is to drive the annular blowing air in the cooling zone A to flow downward. The principle is that the air temperature in the cooling zone B is low, which reduces the air temperature in the cooling zone A. The lower the air temperature, the greater the density, and it is easier to make the annular blowing air in the cooling zone A flow downward; at the same time, the cooling zone B blows air vertically downward, which can form a "vacuum pumping" effect, making the hot air in the cooling zone A flow downward. This improves the fluidity of the air in the cooling zone A, strengthens the slow cooling effect of the cooling zone A on the undrawn tow, and also prevents the upward movement of hot air from interfering with the extrusion of the nascent fibers on the spinneret plate surface. In the prior art, the cooling zone A is directly connected to the duct (i.e., there is no cooling zone B), the heat dissipation effect is not good, and at the same time, the external environmental wind easily affects the shaking of the tow inside the annular blowing, causing the undrawn filaments to "fight" with each other, and easily generating broken ends and hairiness.

[0025] The inner diameter of the annular blowing filter element in the cooling zone A is 270-280 mm, the inner diameter of the cylindrical tube in the cooling zone B is 220-230 mm, and the inner diameter of the cylindrical duct C is 310-320 mm; the inner diameter of the cylindrical duct C is greater than the inner diameter of the annular blowing filter element in the cooling zone A, and the inner diameter of the annular blowing filter element in the cooling zone A is greater than the inner diameter of the cylindrical tube of the cooling air B; the inside of the annular blowing filter element is defined as area A, the inside of the cylindrical tube is defined as area B, and the inside of the cylindrical duct C is defined as area C; the cooling air flow rate in area A = the cooling air flow rate in area B, and the air flow rate formula = wind speed V × cross-sectional area × time. The cross-sectional area is proportional to the pipe diameter. That is to say, within a unit time, because the inner diameter of the annular blowing filter element in the cooling zone A is greater than the inner diameter of the cylindrical tube of the cooling air B, when the annular blowing air in the cooling zone A flows downward, the wind speed in area B is greater than the wind speed in area A. This method not only improves the fluidity of the hot air in area A, but more importantly, the wind speed in area B is increased, which produces a stress stretching effect on the tow, leaving space for the subsequent stretching of the tow, and can reduce the generation of tow hairiness. At the same time, it improves the modulus and dimensional stability of the tow.

[0026] Beneficial effects

[0027] (1) In the method for producing high-modulus and low-shrinkage filaments of the present invention, the annular blowing cooling zone B is added, and blowing vertically downward can form a "vacuum pumping" effect, making the hot air in the cooling zone A flow downward, so that the hot air is easily discharged, reducing the influence of the hot air on the nascent filaments;

[0028] (2) In the prior art, due to poor cooling performance, in order to meet the fiber cooling conditions for high modulus and low shrinkage products, the product specifications in production are generally porous products, such as 1000D / 336f, 1200D / 384f, etc. Although the porous filaments meet the existing cooling production requirements, when the subsequent dipping is used for tires, the fatigue resistance of the porous filaments becomes poor. Therefore, in a method for producing high modulus and low shrinkage filaments of the present invention, hot air can be easily discharged. Thus, there is no need to deliberately design the product as a porous fine filament, and few-hole filaments can be directly produced, increasing the single filament fineness. For example, 1000D / 192f, 1200D / 244f, etc. become a reality. In this way, when the subsequent dipping is used for tires, the fatigue resistance of the tire products is improved. For example, in the prior art, taking a 1000D product as an example, the number of holes is 300 - 380. By improving the fluidity of the cooling air in the present invention and enhancing the cooling effect, the number of holes of the 1000D product can be reduced to 200 - 240, making the product have a better strength retention effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The structural diagram of the device used in a method for producing high modulus and low shrinkage filaments of the present invention;

[0030] Figure 2 The schematic diagrams of two wind directions in a method for producing high modulus and low shrinkage filaments of the present invention;

[0031] Figure 3 The partial enlarged view of the device used in a method for producing high modulus and low shrinkage filaments of the present invention;

[0032] Among them, 1 - spinning box body, 2 - post - heater, 3 - windless area, 4 - cooling area A, 5 - cooling area B, 6 - cylindrical channel C, 7 - air supply opening of cooling area A, 8 - air supply opening of cooling area B, 9 - air diffusing opening of cylindrical channel C, 10 - ring - blowing filter element, 11 - sleeve I, 12 - annular cavity I. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present invention will be further described below in conjunction with the detailed embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0034] The test methods adopted by the present invention are as follows:

[0035] Initial modulus: Using a STATIMAT 4U instrument, the specimen is stretched until fracture with an automatic strength and elongation tester under the test conditions, and the initial modulus value is automatically calculated by computer; Test conditions: Nominal clamping length: 500 mm ± 1 mm, test speed: 500 mm / min, pre-tension: 0.05 ± 0.01 cN / dtex, number of tests: 5 times for each sample.

[0036] Dimensional stability: Referring to GB / T 16604-2017, dimensional stability is the sum of the elongation rate and dry heat shrinkage rate of the fiber under a load of 4.0 cN / dtex.

[0037] Using a STATIMAT 4U instrument, the specimen is stretched until fracture with an automatic strength and elongation tester under the test conditions, and the elongation rate under a load of 4.0 cN / dtex is automatically calculated by computer; Test conditions: Nominal clamping length: 500 mm ± 1 mm, test speed: 500 mm / min, pre-tension: 0.05 ± 0.01 cN / dtex, number of tests: 5 times for each sample. The dry heat shrinkage rate refers to the percentage of the length shrinkage of a 250-mm long filament specimen before and after hot air treatment under the given pre-tension (0.05 ± 0.01 cN / dtex), temperature (177 °C), and time (10 min) conditions using Lanxess TST510. Adding the measured elongation rate under a load of 4.0 cN / dtex and the dry heat shrinkage rate gives the dimensional stability.

[0038] Example 1

[0039] A method for producing high-modulus and low-shrinkage filaments, the specific process is as follows:

[0040] As Figure 1 shown, the filament extruded from the spinneret plate in the spinning box 1 enters the post-heater 2, and after being pre-cooled successively through a slow cooling zone with a height of 105 mm and a windless zone 3 with a height of 55 mm, it enters the cooling zone for cooling and forming to obtain high-modulus and low-shrinkage filaments;

[0041] The cooling zone includes successively connected cooling zone A 4 and cooling zone B 5 from top to bottom, and a cylindrical duct C 6 connected below cooling zone B 5;

[0042] As Figures 2 - 3As shown in the figure, the cooling zone A4 is a cylindrical air duct with a height of 460 mm. The air supply port 7 of the cooling zone A is located in the upper left corner, and the air outlet is located inside. The air blows from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow. Inside the cooling zone A4, there is a ring-blowing filter element 10 with an inner diameter of 280 mm. Outside the cooling zone A4, there is a sleeve I11 with a diameter larger than that of the ring-blowing filter element 10 and coaxial with the ring-blowing filter element 10. An annular cavity I12 is formed between the ring-blowing filter element 10 and the sleeve I11. The upper and lower parts of the annular cavity I are sealed, and the annular cavity I12 is used for the cooling air to enter. The distance between the inner wall of the sleeve I11 and the outer wall of the ring-blowing filter element 10 (i.e., the width of the annular cavity I12) is 2 cm;

[0043] The cooling zone B5 is a cylindrical air duct with a height of 410 mm. The air supply port 8 of the cooling zone B is located in the upper left side, and the air outlet is located at the lower end. The air blows from top to bottom, and the blowing direction is parallel to the running direction of the tow. Inside the cooling zone B5, there is a cylindrical pipe with an inner diameter of 230 mm. Outside the cooling zone B5, there is a sleeve II with a diameter larger than that of the cylindrical pipe and coaxial with the cylindrical pipe. An annular cavity II is formed between the cylindrical pipe and the sleeve II. The annular cavity II is used for the cooling air to enter, and the top of the annular cavity II is sealed. The distance between the inner wall of the sleeve II and the outer wall of the cylindrical pipe (i.e., the width of the annular cavity II) is 2 cm; The bottom of the sleeve I is fixedly connected to the top of the sleeve II;

[0044] The height of the cylindrical passage C6 is 710 mm, and the inner diameter is 320 mm; The cooling air is dispersed through the air dispersion port 9 of the cylindrical passage C;

[0045] Among them, the ambient temperature is 40 °C. The blowing temperature of the cooling zone A4 is 10 °C higher than the ambient temperature, and the blowing temperature of the cooling zone B5 is 15 °C lower than the ambient temperature; The spinning speed is 3400 m / min, and the winding speed is 6200 m / min.

[0046] The monofilament fineness of the obtained high-modulus low-shrinkage filament is 5.65 dtex, the number of fiber roots is 200 f, the initial modulus is 110 cN / dtex, and the dimensional stability is 7%.

[0047] Comparative Example 1

[0048] A method for producing high-modulus low-shrinkage filaments is basically the same as that in Example 1, except that there is no cooling zone B (i.e., the cooling zone A is directly connected to the cylindrical passage C).

[0049] The monofilament fineness of the obtained high-modulus low-shrinkage filament is 3.14 dtex, the number of fiber roots is 360 f, the initial modulus is 97 cN / dtex, and the dimensional stability is 9%.

[0050] Comparing Comparative Example 1 with Example 1, it can be found that the initial modulus of Comparative Example 1 is relatively small and the dimensional stability is relatively large. This is because the cooling effect does not reach the cooling effect in this invention patent. It can only be achieved by increasing the number of spinneret holes. However, when the number of spinneret holes increases, the spinning condition stability at high speed becomes worse. To balance the spinning condition, the spinning speed can only be reduced. Therefore, in the comparative example, the initial modulus is relatively low and the dimensional stability is relatively large.

[0051] Example 2

[0052] A method for producing high modulus and low shrinkage filaments, the specific process is as follows:

[0053] The filaments extruded through the spinneret plate pass through a slow cooling zone with a height of 95 mm and a windless zone with a height of 45 mm for pre-cooling in sequence, and then enter the cooling zone for cooling and forming to obtain high modulus and low shrinkage filaments;

[0054] The cooling zone includes a connected Cooling Zone A and Cooling Zone B from top to bottom, and a cylindrical duct C connected below Cooling Zone B;

[0055] Cooling Zone A is a cylindrical air duct with a height of 440 mm. The air supply port of Cooling Zone A is located in the upper left corner, and the air outlet is located inside. It blows air from the outside to the inside, and the blowing direction is perpendicular to the running direction of the filament bundle. Inside Cooling Zone A, there is a ring blowing filter element with an inner diameter of 270 mm. Outside Cooling Zone A, there is a sleeve I with a diameter larger than the ring blowing filter element and coaxial with it. An annular cavity I is formed between the ring blowing filter element and the sleeve I. The upper and lower parts of the annular cavity I are sealed, and the annular cavity I is used for the cooling air to enter. The distance between the inner wall of the sleeve I and the outer wall of the ring blowing filter element (i.e., the width of the annular cavity I) is 1 cm;

[0056] Cooling Zone B is a cylindrical air duct with a height of 390 mm. The air supply port of Cooling Zone B is located in the upper left corner, and the air outlet is located at the lower end. It blows air from top to bottom, and the blowing direction is parallel to the running direction of the filament bundle. Inside Cooling Zone B, there is a cylindrical pipe with an inner diameter of 220 mm. Outside Cooling Zone B, there is a sleeve II with a diameter larger than the cylindrical pipe and coaxial with it. An annular cavity II is formed between the cylindrical pipe and the sleeve II. The annular cavity II is used for the cooling air to enter, and the top of the annular cavity II is sealed. The distance between the inner wall of the sleeve II and the outer wall of the cylindrical pipe (i.e., the width of the annular cavity II) is 1 cm; The bottom of the sleeve I is fixedly connected to the top of the sleeve II;

[0057] The cylindrical duct C has a height of 690 mm and an inner diameter of 310 mm;

[0058] Among them, the ambient temperature is 35 °C, the blowing temperature of Cooling Zone A is 15 °C higher than the ambient temperature, and the blowing temperature of Cooling Zone B is 10 °C lower than the ambient temperature; the spinning speed is 3000 m / min, and the winding speed is 5800 m / min.

[0059] The fineness of the monofilament of the obtained high modulus and low shrinkage filament is 4.71 dtex, the number of fibers is 240 f, the initial modulus is 105 cN / dtex, and the dimensional stability is 8.50%.

[0060] Example 3

[0061] A production method of high modulus and low shrinkage filament, the specific process is as follows:

[0062] The filament extruded through the spinneret passes through a slow cooling zone with a height of 97 mm and a windless zone with a height of 47 mm for pre-cooling in sequence, and then enters the cooling zone for cooling and forming to obtain the high modulus and low shrinkage filament;

[0063] The cooling zone includes a connected cooling zone A and cooling zone B from top to bottom and a cylindrical duct C connected below the cooling zone B;

[0064] The cooling zone A is a cylindrical air duct with a height of 445 mm. The air supply opening of the cooling zone A is located in the upper left, and the air outlet is located inside. It blows air from the outside to the inside, and the blowing direction is perpendicular to the running direction of the filament bundle; An annular blowing filter element with an inner diameter of 272 mm is arranged inside the cooling zone A. A sleeve I with a diameter larger than the annular blowing filter element and coaxial with the annular blowing filter element is arranged outside the cooling zone A. An annular cavity I is formed between the annular blowing filter element and the sleeve I. The upper and lower parts of the annular cavity I are sealed, and the annular cavity I is used for the cooling air to enter; The distance between the inner wall of the sleeve I and the outer wall of the annular blowing filter element (i.e., the width of the annular cavity I) is 1.2 cm;

[0065] The cooling zone B is a cylindrical air duct with a height of 395 mm. The air supply opening of the cooling zone B is located in the upper left, and the air outlet is located at the lower end. It blows air from top to bottom, and the blowing direction is parallel to the running direction of the filament bundle; A cylindrical tube with an inner diameter of 222 mm is arranged inside the cooling zone B. A sleeve II with a diameter larger than the cylindrical tube and coaxial with the cylindrical tube is arranged outside the cooling zone B. An annular cavity II is formed between the cylindrical tube and the sleeve II. The annular cavity II is used for the cooling air to enter, and the top of the annular cavity II is sealed; The distance between the inner wall of the sleeve II and the outer wall of the cylindrical tube (i.e., the width of the annular cavity II) is 1.2 cm; The bottom of the sleeve I is fixedly connected to the top of the sleeve II;

[0066] The height of the cylindrical duct C is 695 mm, and the inner diameter is 312 mm;

[0067] Among them, the ambient temperature is 36 °C, the blowing temperature of the cooling zone A is 5 °C higher than the ambient temperature, and the blowing temperature of the cooling zone B is 11 °C lower than the ambient temperature; The spinning speed is 3100 m / min, and the winding speed is 5900 m / min.

[0068] The fineness of the monofilament of the obtained high modulus and low shrinkage filament is 4.81 dtex, the number of fibers is 235 f, the initial modulus is 106 cN / dtex, and the dimensional stability is 8.20%.

[0069] Example 4

[0070] A production method of high modulus and low shrinkage filament, the specific process is as follows:

[0071] The filament extruded through the spinneret is pre-cooled successively in a slow cooling zone with a height of 99 mm and a windless zone with a height of 49 mm, and then enters the cooling zone for cooling and forming to obtain high modulus and low shrinkage filament;

[0072] The cooling zone includes a connected cooling zone A and cooling zone B from top to bottom, and a cylindrical duct C connected below the cooling zone B;

[0073] The cooling zone A is a cylindrical air duct with a height of 450 mm. The air supply port of the cooling zone A is located in the upper left, and the air outlet is located inside. It blows air from the outside to the inside, and the blowing direction is perpendicular to the running direction of the filament bundle; Inside the cooling zone A, there is a ring blowing filter element with an inner diameter of 274 mm. Outside the cooling zone A, there is a sleeve I with a diameter larger than the ring blowing filter element and coaxial with the ring blowing filter element. An annular cavity is formed between the ring blowing filter element and the sleeve I. The upper and lower parts of the annular cavity I are sealed, and the annular cavity I is used for the cooling air to enter; The distance between the inner wall of the sleeve I and the outer wall of the ring blowing filter element (i.e., the width of the annular cavity I) is 1.4 cm;

[0074] The cooling zone B is a cylindrical air duct with a height of 400 mm. The air supply port of the cooling zone B is located in the upper left, and the air outlet is located at the lower end. It blows air from top to bottom, and the blowing direction is parallel to the running direction of the filament bundle; Inside the cooling zone B, there is a cylindrical tube with an inner diameter of 224 mm. Outside the cooling zone B, there is a sleeve II with a diameter larger than the cylindrical tube and coaxial with the cylindrical tube. An annular cavity II is formed between the cylindrical tube and the sleeve II. The annular cavity II is used for the cooling air to enter, and the top of the annular cavity II is sealed; The distance between the inner wall of the sleeve II and the outer wall of the cylindrical tube (i.e., the width of the annular cavity II) is 1.4 cm; The bottom of the sleeve I is fixedly connected to the top of the sleeve II;

[0075] The cylindrical duct C has a height of 700 mm and an inner diameter of 314 mm;

[0076] Among them, the ambient temperature is 37 °C, the blowing temperature of the cooling zone A is 7 °C higher than the ambient temperature, and the blowing temperature of the cooling zone B is 12 °C lower than the ambient temperature; The spinning speed is 3200 m / min, and the winding speed is 6000 m / min.

[0077] The single filament fineness of the obtained high modulus and low shrinkage filament is 4.91 dtex, the number of filaments is 230 f, the initial modulus is 107 cN / dtex, and the dimensional stability is 7.80%.

[0078] Example 5

[0079] A method for producing high modulus and low shrinkage filaments, the specific process is as follows:

[0080] The filaments extruded through the spinneret are successively pre-cooled in a slow cooling zone with a height of 100 mm and a windless zone with a height of 51 mm, and then enter the cooling zone for cooling and forming to obtain high modulus and low shrinkage filaments;

[0081] The cooling zone includes a connected cooling zone A and cooling zone B from top to bottom, and a cylindrical duct C connected below cooling zone B;

[0082] Cooling zone A is a cylindrical air duct with a height of 455 mm. The air supply opening of cooling zone A is located in the upper left, and the air outlet is located inside. It blows air from outside to inside, and the blowing direction is perpendicular to the running direction of the filament bundle. An annular blowing filter element with an inner diameter of 275 mm is arranged inside cooling zone A. A sleeve I with a diameter larger than the annular blowing filter element and coaxial with it is arranged outside cooling zone A. An annular cavity I is formed between the annular blowing filter element and sleeve I. The upper and lower parts of the annular cavity I are sealed, and the annular cavity I is used for cooling air to enter. The distance between the inner wall of sleeve I and the outer wall of the annular blowing filter element (i.e., the width of the annular cavity I) is 1.5 cm;

[0083] Cooling zone B is a cylindrical air duct with a height of 405 mm. The air supply opening of cooling zone B is located in the upper left, and the air outlet is located at the lower end. It blows air from top to bottom, and the blowing direction is parallel to the running direction of the filament bundle. A cylindrical pipe with an inner diameter of 225 mm is arranged inside cooling zone B. A sleeve II with a diameter larger than the cylindrical pipe and coaxial with it is arranged outside cooling zone B. An annular cavity II is formed between the cylindrical pipe and sleeve II. The annular cavity II is used for cooling air to enter, and the top of the annular cavity II is sealed. The distance between the inner wall of sleeve II and the outer wall of the cylindrical pipe (i.e., the width of the annular cavity II) is 1.5 cm; The bottom of sleeve I is fixedly connected to the top of sleeve II;

[0084] The cylindrical duct C has a height of 705 mm and an inner diameter of 315 mm;

[0085] Among them, the ambient temperature is 38 °C, the blowing temperature of cooling zone A is 10 °C higher than the ambient temperature, and the blowing temperature of cooling zone B is 13 °C lower than the ambient temperature; the spinning speed is 3300 m / min, and the winding speed is 6100 m / min.

[0086] The single filament fineness of the obtained high modulus and low shrinkage filaments is 5.14 dtex, the number of fiber filaments is 220 f, the initial modulus is 108 cN / dtex, and the dimensional stability is 7.50%.

[0087] Example 6

[0088] A method for producing high modulus and low shrinkage filaments, the specific process is as follows:

[0089] The filaments extruded through the spinneret are pre-cooled successively in a slow cooling zone with a height of 103 mm and a windless zone with a height of 53 mm, and then enter the cooling zone for cooling and shaping to obtain high modulus and low shrinkage filaments;

[0090] The cooling zone includes successively connected cooling zone A and cooling zone B from top to bottom, and a cylindrical duct C connected below cooling zone B;

[0091] Cooling zone A is a cylindrical air duct with a height of 458 mm. The air supply port of cooling zone A is located in the upper left, and the air outlet is located inside. It blows air from outside to inside, and the blowing direction is perpendicular to the running direction of the filament bundle. Inside cooling zone A, there is a ring blowing filter element with an inner diameter of 278 mm. Outside cooling zone A, there is a sleeve I with a diameter larger than the ring blowing filter element and coaxial with the ring blowing filter element. An annular cavity I is formed between the ring blowing filter element and the sleeve I. The upper and lower parts of the annular cavity I are sealed, and the annular cavity I is used for the entry of cooling air. The distance between the inner wall of the sleeve I and the outer wall of the ring blowing filter element (i.e., the width of the annular cavity I) is 1.8 cm;

[0092] Cooling zone B is a cylindrical air duct with a height of 408 mm. The air supply port of cooling zone B is located in the upper left, and the air outlet is located at the lower end. It blows air from top to bottom, and the blowing direction is parallel to the running direction of the filament bundle. Inside cooling zone B, there is a cylindrical pipe with an inner diameter of 228 mm. Outside cooling zone B, there is a sleeve II with a diameter larger than the cylindrical pipe and coaxial with the cylindrical pipe. An annular cavity II is formed between the cylindrical pipe and the sleeve II. The annular cavity II is used for the entry of cooling air, and the top of the annular cavity II is sealed. The distance between the inner wall of the sleeve II and the outer wall of the cylindrical pipe (i.e., the width of the annular cavity II) is 1.8 cm; The bottom of the sleeve I is fixedly connected to the top of the sleeve II;

[0093] The height of the cylindrical duct C is 708 mm, and the inner diameter is 316 mm;

[0094] Among them, the ambient temperature is 40 °C, the blowing temperature of cooling zone A is 10 °C higher than the ambient temperature, and the blowing temperature of cooling zone B is 14 °C lower than the ambient temperature; the spinning speed is 3350 m / min, and the winding speed is 6150 m / min.

[0095] The single filament fineness of the obtained high modulus and low shrinkage filaments is 5.38 dtex, the number of filaments is 210 f, the initial modulus is 109.5 cN / dtex, and the dimensional stability is 7.20%.

Claims

1. A method for producing high-modulus low-shrinkage filaments, characterized in that: The filaments extruded through the spinneret are pre-cooled successively in the slow-cooling zone and the windless zone, and then enter the cooling zone for cooling and shaping to obtain high-modulus and low-shrinkage filaments; The cooling zone includes successively the cooling zone A and the cooling zone B connected from top to bottom, and a cylindrical duct C connected below the cooling zone B; The cooling zone A is a cylindrical air duct with the air outlet on the inner side, and the blowing direction is perpendicular to the running direction of the filament bundle; an annular blowing filter element is arranged inside the cooling zone A, and a sleeve I with a diameter larger than that of the annular blowing filter element and coaxial with the annular blowing filter element is arranged outside the cooling zone A. An annular cavity I is formed between the annular blowing filter element and the sleeve I, and the annular cavity I is used for the cooling air to enter; The cooling zone B is a cylindrical air duct with the air outlet at the lower end, and the blowing direction is parallel to the running direction of the filament bundle; a cylindrical pipe is arranged inside the cooling zone B, and a sleeve II with a diameter larger than that of the cylindrical pipe and coaxial with the cylindrical pipe is arranged outside the cooling zone B. An annular cavity II is formed between the cylindrical pipe and the sleeve II, and the annular cavity II is used for the cooling air to enter, and the top of the annular cavity II is sealed; the distance between the inner wall of the sleeve II and the outer wall of the cylindrical pipe is 1-2 cm; the bottom of the sleeve I is fixedly connected to the top of the sleeve II. The blowing temperature in the cooling zone A is 5-15 °C higher than the ambient temperature, being 40-50 °C, and the blowing temperature in the cooling zone B is 10-15 °C lower than the ambient temperature; The inner diameter of the cooling zone A is larger than that of the cooling zone B, and the inner diameter of the cooling zone A is smaller than the inner diameter of the cylindrical duct C.

2. The production method of a high modulus and low shrinkage filament according to claim 1, characterized in that, The ambient temperature is 35-40 °C.

3. A method for producing high-modulus low-shrinkage filaments according to claim 1, characterized in that, The distance between the inner wall of the sleeve I and the outer wall of the annular blowing filter element is 1-2 cm.

4. A method for producing high modulus and low shrinkage yarn according to claim 1, characterized in that, The inner diameter of the annular blowing filter element in the cooling zone A is 270-280 mm, the inner diameter of the cylindrical pipe in the cooling zone B is 220-230 mm, and the inner diameter of the cylindrical duct C is 310-320 mm.

5. A method for producing high modulus low shrinkage yarn according to claim 4, characterized in that, The height of the slow-cooling zone is 95-105 mm, the height of the windless zone is 45-55 mm, the height of the cooling zone A is 440-460 mm, the height of the cooling zone B is 390-410 mm, and the height of the cylindrical duct C is 690-710 mm.

6. A method for producing high-modulus low-shrinkage yarn according to claim 5, characterized in that, The single-filament fineness of the high-modulus and low-shrinkage filaments is 4.71-5.65 dtex, and the number of filaments is 200-240 f.

7. A method for producing high modulus and low shrinkage filaments according to claim 6, characterized in that, The spinning speed is 3000-3400 m / min, and the winding speed is 5800-6200 m / min.

8. A method for producing high modulus and low shrinkage yarn according to claim 7, characterized in that, The initial modulus of the high-modulus and low-shrinkage filaments is 105-110 cN / dtex, and the dimensional stability is 7-8.5%.

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