Manufacturing method for high modulus low shrinkage yarn

Abstract

This invention relates to a method for producing high modulus low shrinkage yarn. A yarn bundle extruded from a spinneret is pre-cooled in a slow-cooling region and a windless region, then enters a cooling region and is cooled and molded to obtain high modulus low shrinkage yarn. The cooling region consists of a continuous cooling region A and cooling region B, and a cylindrical cooling cylinder C connected below cooling region B, running from top to bottom. Cooling region A is a cylindrical blower cylinder with an air outlet located on the inside and the airflow direction perpendicular to the direction of travel of the yarn bundle. Cooling region B is a cylindrical blower cylinder with an air outlet located at the bottom end and the airflow direction parallel to the direction of travel of the yarn bundle. The method for producing high modulus low shrinkage yarn of this invention adds a ring-blowing cooling region B and generates a Bernoulli effect by blowing air vertically downward, causing the hot air in cooling region A to flow downward and easily discharge the hot air, thereby reducing the influence of the hot air on the extrusion of the molten material.

Description

Technical Field

[0004] , , , , , ,

[0005] , , ,

[0001] The present invention belongs to the technical field of spinning and relates to a method for manufacturing high elastic modulus and low shrinkage yarns.

Background Art

[0002] Industrial high elastic modulus and low shrinkage polyester yarns are mainly used as tire cords, and high strength and excellent dimensional stability are required as the skeletal materials of automobile tires. The physical property requirements are to have high strength, high elastic modulus, and low dry heat shrinkage, and the dimensional stability is affected by the constant load elongation rate and the dry heat shrinkage performance. According to the literature (Development of high elastic modulus and low shrinkage polyester industrial yarns. Synthetic Fiber Industry, 2013, 36(1):67 - 69.), in order to achieve a high elastic modulus of polyester industrial yarns, a high spinning speed is required. In order to avoid crystallization due to rapid cooling of the undrawn yarn, in the production of high elastic modulus and low shrinkage products, cooling with hot air at 40°C or higher is usually used, and in order to reduce the yarn thickness, promote uniform cooling of the yarn bundle, and prevent the skin - core structure, a porous spinning die is required. However, in the current production process, since the hot air in the spinning cylinder has a lower density than the external environmental air, it is difficult to be discharged and its fluidity decreases, which affects the cooling of the undrawn fibers. On the other hand, since it is difficult for the hot air to be discharged downward, it moves upward and reaches the surface of the spinning die, which easily inhibits the fiber formation, causes spiral extrudates and plate adhesion, reduces the spinning property, and also has an adverse effect on improving the dimensional stability of high elastic and low shrinkage products.

[0003] Therefore, the development of a high elastic and low shrinkage production method to solve the poor fluidity of hot air in the cooling air has extremely important significance.

Summary of the Invention

Problems to be Solved by the Invention

[0004] To solve the problems of the existing technology, the present invention provides a method for manufacturing high elastic modulus and low shrinkage yarns.

Means for Solving the Problems

[0005] To achieve the above objective, the present invention employs the following approach: In a method for producing high modulus low shrinkage yarn, the yarn bundle extruded from the spinneret undergoes pre-cooling in a slow-cooling region and a windless region, then enters a cooling region where it is cooled and molded to obtain high modulus low shrinkage yarn. Within this, the cooling region includes a continuous cooling region A and cooling region B from top to bottom, and a cylindrical cooling tube C connected below cooling region B; cooling region A is a cylindrical air duct with an air outlet located on the inside, blowing air from the outside to the inside, and the direction of airflow is perpendicular to the direction of travel of the yarn bundle; cooling region B is a cylindrical air duct with an air outlet located at the bottom end, blowing air from top to bottom, and the direction of airflow is parallel to the direction of travel of the fiber bundle; the air temperature in cooling region A is 5 to 15°C higher than the ambient temperature, at 40 to 50°C, and the air temperature in cooling region B is 10 to 15°C lower than the ambient temperature; the inner diameter of cooling region A is larger than the inner diameter of cooling region B, and the inner diameter of cooling region A is smaller than the inner diameter of the cylindrical passage C.

[0006] As a preferred technical solution: In the above-described method for producing high-modulus, low-shrinkage yarn, the ambient temperature is 35-40°C. Although the air conditioning temperature in the fiber manufacturing environment is approximately 25°C, the actual manufacturing environment temperature (room temperature) is 35-40°C due to the presence of numerous heating devices and the heat energy of the high-temperature molten material.

[0007] In the above-described method for manufacturing high modulus low shrinkage yarn, a ring-blowing filter core is installed inside the cooling region A, and a sleeve I, which is larger in diameter than the ring-blowing filter core and coaxial with it, is provided outside the cooling region A. An annular cavity is formed between the ring-blowing filter core and the sleeve I, and this annular cavity I serves as the inflow path for cooling air. The upper and lower parts of the annular cavity I are sealed from the outside. During operation, cooling air flows in from the air duct and fills the annular cavity I, then penetrates the ring-blowing filter core and cools the yarn passing through its center.

[0008] In the above method for producing high modulus low shrinkage yarn, the distance between the inner wall of sleeve I and the outer wall of the ring-blown filter (i.e., the width of the annular cavity I) is 1 to 2 cm.

[0009] In the above-described method for manufacturing high modulus low shrinkage yarn, a cylindrical tube is installed inside the cooling region B, and a sleeve II, which is larger in diameter than the cylindrical tube and coaxial with it, is provided on the outside. An annular cavity II is formed between the cylindrical tube and sleeve II to function as an introduction point for cooling air, and its upper part is sealed. The distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 1 to 2 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected. During operation, cooling air enters and fills the annular cavity II through the air duct, and then enters the cooling cylinder from the bottom of annular cavity II. Furthermore, it is preferable that sleeve I and sleeve II be integrally molded parts.

[0010] In the method for manufacturing high modulus and low shrinkage rate yarn as described above, the inner diameter of the ring-blown filter core in cooling region A is 270-280 mm, the inner diameter of the cylindrical tube in cooling region B is 220-230 mm, and the inner diameter of the cylindrical cooling tube C is 310-320 mm.

[0011] In the above-described method for manufacturing high modulus low shrinkage yarn, the height of the slow-cooling region is 95-105 mm, the height of the windless region is 45-55 mm, the height of cooling region A is 440-460 mm, the height of cooling region B is 390-410 mm, and the height of the cylindrical cooling tube C is 690-710 mm. The principle of the high modulus low shrinkage yarn forming process is to obtain a product with high modulus and high dimensional stability by high-speed spinning and rapid cooling. Therefore, by reducing the slow-cooling region and windless region and strengthening extreme cooling, the modulus and dimensional stability of the product can be improved.

[0012] In the above-described method for producing high-modulus, low-shrinkage yarn, the single fiber fineness of the high-modulus, low-shrinkage yarn is 4.71 to 5.65 dtex, and the number of single fibers is 200 to 240.

[0013] In the above-described method for producing high-modulus, low-shrinkage yarn, the spinning speed (first hot roller speed) is 3000-3400 m / min, and the winding speed is 5800-6200 m / min. In the production of high-strength, low-shrinkage yarn using conventional technology, the first hot roller speed is 2600-3000 m / min, and the winding speed is 5200-5400 m / min. In the production of high-modulus, low-shrinkage yarn using conventional technology, it is possible to further increase the first hot roller speed and winding speed, but increasing the speed increases yarn breakage, as well as fuzzing and appearance defects. The cooling improvement of the present invention reduces the number of nozzle holes and increases the thickness of the single fibers, thereby improving the resistance to stretching of the yarn bundle and enabling production at higher speeds and stretch ratios. Higher speeds improve the modulus of elasticity and dimensional stability of the product, and a higher stretch ratio increases the strength of the product.

[0014] In the above-described method for producing high-modulus, low-shrinkage yarn, the initial modulus of elasticity of the high-modulus, low-shrinkage yarn is 105-110 cN / dtex, and the dimensional stability index is 7-8.5%.

[0015] Taking a conventional 1000D product as an example, its actual fineness is 1130 dtex, the number of single fibers is 300-360, and the single fiber fineness is 3.14-3.77 dtex. By increasing the flow rate of the cooling air using the method of the present invention and solving the problem of uneven cooling due to excessive single fiber fineness, the number of single fibers can be improved to 200-240, and the short fiber fineness becomes 4.71-5.65 dtex while the actual fineness remains unchanged. The improvement in single fiber fineness creates room for a higher spinning speed in the fiber forming process. In other words, it becomes possible to more effectively improve the spinning speed and draw ratio while maintaining the spinning state and fiber appearance. If only the number of holes is reduced without changing the forming process, and the elastic modulus and dimensional stability of the product remain basically unchanged, the present invention solves the problem of uneven cooling after reducing the number of nozzle holes by improving the efficiency of the cooling air, thereby achieving improved spinning speed and improved elastic modulus and dimensional stability of the product.

[0016] The principle of this invention is as follows:

[0017] In cooling region B, a low-temperature cooling air of 20-25°C is blown parallel to the direction of travel of the yarn bundle. The purpose is to secondary cool the yarn bundle and equalize the cooling effect inside and outside. The second purpose is to guide the circulating airflow in cooling region A downward. The principle is that the low air temperature in cooling region B lowers the air temperature in cooling region A, and as the air temperature decreases, the density increases, making it easier to guide the circulating airflow in cooling region A downward. At the same time, the cooling air blows vertically downward in cooling region B, forming the Bernoulli effect, which causes the hot air in cooling region A to flow downward. This improves the airflow within cooling region A, strengthening the slow cooling effect on the undrawn yarn bundle, while simultaneously preventing the upward movement of hot air from hindering molten extrusion at the spinneret surface. In conventional technology, cooling region A is directly connected to the spinning cylinder (cooling region B does not exist), resulting in insufficient heat dissipation. At the same time, the movement of the yarn bundle inside the spinning cylinder becomes more intense due to the wind in the external environment, causing the yarn to bunch together among the uncooled monofilaments, making it prone to breakage and fuzzing.

[0018] The inner diameter of the ring-blowing filter core in cooling region A is 270-280 mm, the inner diameter of the cylindrical tube in cooling region B is 220-230 mm, and the inner diameter of the cylindrical cooling tube C is 310-320 mm. The inner diameter of the cylindrical cooling tube C is larger than the inner diameter of the ring-blowing filter core in cooling region A, and the inner diameter of the ring-blowing filter core in cooling region A is larger than the inner diameter of the cylindrical tube in cooling region B. If we define the inside of the ring-blowing filter core as region a and the inside of the cylindrical tube as region b, then the cooling airflow rate in region a = cooling airflow rate in region b, and the airflow rate = wind speed × cross-sectional area, and the cross-sectional area is proportional to the pipe diameter. Therefore, per unit time, if the inner diameter of the ring-blowing filter core in cooling region A is larger than the inner diameter of the cylindrical tube in cooling region B, then when the ring-blowing air in cooling region A descends, the wind speed in region b will be greater than in region a. This method not only improves the fluidity of the hot air in zone A, but more importantly, the difference in air frictional resistance caused by the difference in air velocity between zones a and b provides an equivalent stretching effect to the yarn, giving the undrawn yarn a certain pre-orientation. This allows it to withstand higher stretching stress in the subsequent heat-drawing process, reducing fuzzing of the yarn bundle and simultaneously improving the elastic modulus and dimensional stability of the yarn. [Effects of the Invention]

[0019] The advantages of the present invention include, (1) The present invention provides a method for producing high modulus and low shrinkage fibers by adding a ring-blowing cooling region B and blowing air vertically downward to generate the Bernoulli effect, thereby guiding the hot airflow within the cooling region A downward and easily discharging the hot air, thereby reducing the influence of hot air on molten extrusion.

[0020] (2) In the prior art, since the cooling effect is poor, in order to meet the cooling of the high elastic modulus and low shrinkage yarn, it is usually produced with a large number of multifilaments (e.g., 1000D / 336f, 1200D / 384f, etc.). Although a large number of multifilaments can be produced according to the current cooling production requirements, when used in tires after rubber impregnation in the subsequent process, the fatigue resistance decreases. Therefore, in the method for manufacturing the high elastic modulus and low shrinkage yarn of the present invention, since hot air can be easily discharged, there is no need to intentionally design a large number of multifilaments, and it is possible to directly produce with a small number of filaments and increase the single filament fineness. For example, 1000D / 192f, 1200D / 244f, etc. are achievable, and thereby, when manufacturing tires by rubber dipping in the subsequent process, the fatigue resistance of the tire product is improved. For example, taking a 1000D product according to the prior art as an example, the number of single fibers was usually 300 - 380, but the present invention enhances the cooling effect by improving the fluidity of the cooling air and can reduce the number of single fibers of the 1000D product to 200 - 240, so the product exhibits a better strength retention effect.

Brief Description of the Drawings

[0021] [Figure 1] It is a structural diagram of the apparatus used in the method for manufacturing the high elastic modulus and low shrinkage yarn of the present invention. [Figure 2] It is a schematic diagram of two types of air blowing directions in the method for manufacturing the high elastic modulus and low shrinkage yarn of the present invention. [Figure 3] It is a partially enlarged view of the apparatus used in the method for manufacturing the high elastic modulus and low shrinkage yarn of the present invention.

Embodiments for Carrying Out the Invention

[0022] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as it does not exceed the gist. Even if those skilled in the art who have read the content of the present invention make various modifications to the present invention, they are also limited within the scope of the claims of the present invention as equivalent forms of the present invention.

[0023] The test method adopted in the present invention is as follows: Initial elastic modulus: Using the STATIMAT 4U device, the sample is subjected to a tensile test until fracture by an automatic tensile testing machine under the test conditions, and the initial elastic modulus value is automatically calculated by a computer. Test conditions: Nominal gripping length: 500 mm ± 1 mm, test speed: 500 mm / min, pre-tension: 0.05 ± 0.01 cN / dtex, number of tests: 5 measurements for each sample.

[0024] Dimensional stability index: In accordance with Chinese National Standard GB / T 16604-2017, it is the sum of the elongation rate and the dry heat shrinkage rate under a load of 4.0 cN / dtex of the fiber.

[0025] Using the STATIMAT 4U device, the test piece is pulled until fracture by an automatic tensile testing machine under the test conditions. The elongation rate at a load of 4.0 cN / dtex is automatically calculated by a computer. Test conditions: Specified gripping length: 500 mm ± 1 mm, test speed: 500 mm / min, pre-tension: 0.05 ± 0.01 cN / dtex, number of tests: 5 measurements for each sample. The dry heat shrinkage rate refers to the value calculated as a percentage of the shrinkage rate of the yarn sample with a length of 250 mm processed by hot air under the conditions of a predetermined pre-tension (0.05 ± 0.01 cN / dtex), temperature (177 °C), and time (10 minutes) using Lenzing TST510. The sum of the elongation rate and the dry heat shrinkage rate under a load of 4.0 cN / dtex after the test is the dimensional stability index. According to this definition, it can be seen that the higher the dimensional stability index, the lower the dimensional stability of the fiber.

[0026] Example 1 Method for manufacturing a high elastic modulus and low shrinkage yarn, the specific steps are as follows: As shown in Figure 1, the yarn extruded from the spinneret in the spinning pack 1 enters the rear heater 2, is pre-cooled in a slow cooling region with a height of 105 mm and a windless region 3 with a height of 55 mm, and then cooled and formed in the cooling region to produce a high elastic modulus and low shrinkage yarn.

[0027] The cooling area consists of a continuous cooling area A4 and cooling area B5 from top to bottom, and a cylindrical cooling tube C6 connected below cooling area B5.

[0028] As shown in Figures 2-3, the cooling region A4 is a cylindrical air duct with a height of 460 mm. Its air outlet 7 is located in the upper left and is on the inside, blowing air from the outside to the inside, with the airflow direction perpendicular to the direction of the yarn bundle's movement. Inside the cooling region A4, a ring-blowing filter core 10 with an inner diameter of 280 mm is installed, and on the outside, a sleeve I 11 with a larger diameter than the ring-blowing filter core 10 and coaxial with it is provided, forming an annular cavity I 12 between the ring-blowing filter core 10 and the sleeve I 11. The annular cavity I 12 is sealed at its top and bottom and serves as the inflow path for the cooling air. The distance between the inner wall of the sleeve I 11 and the outer wall of the ring-blowing filter core 10 (i.e., the width of the annular cavity I 12) is 2 cm.

[0029] Cooling area B5 is a cylindrical air duct with a height of 410 mm. The air outlet 8 of cooling area B is located on the upper left side, and the outlet is at the bottom end, blowing air from top to bottom, with the airflow direction parallel to the direction of the thread bundle's movement. Inside cooling area B5 is a cylindrical tube with an inner diameter of 230 mm, and on the outside is a coaxial sleeve II with a larger diameter than the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II to serve as the airflow path for cooling. The top of the annular cavity II is sealed, and the distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 2 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected.

[0030] The cylindrical cooling tube C6 has a height of 710 mm and an inner diameter of 320 mm, and the cooling air is discharged through the exhaust port 9 of the cylindrical cooling tube C.

[0031] Here, the ambient temperature is 40°C, the air temperature in cooling area A4 is 10°C higher than the ambient temperature, and the air temperature in cooling area B5 is 15°C lower than the ambient temperature. The spinning speed is 3400 m / min, and the winding speed is 6200 m / min.

[0032] The obtained high modulus of elasticity and low shrinkage yarn has a single fiber fineness of 5.65 dtex, a single fiber count of 200 f, an initial modulus of elasticity of 110 cN / dtex, and a dimensional stability index of 7%.

[0033] Comparative Example 1 This method is for producing a high modulus of elasticity and low shrinkage yarn, and is basically the same as in Example 1, but the difference is that there is no cooling region B (i.e., cooling region A is directly connected to the cylindrical cooling tube C).

[0034] The obtained high modulus of elasticity and low shrinkage yarn has a single fiber fineness of 3.14 dtex, a single fiber count of 360 f, an initial modulus of elasticity of 97 cN / dtex, and a dimensional stability index of 9%.

[0035] Comparing Comparative Example 1 with Example 1, it can be seen that Comparative Example 1 has a lower initial modulus of elasticity and a higher dimensional stability index. The reason for this is that the Comparative Example does not employ the cooling device of the present invention (Example 1), so only a large number of spindle holes can be used to achieve a similar cooling effect. However, increasing the number of spindle holes reduces spinning stability at high speeds, so considering the spinning state, it is necessary to reduce the spinning speed.

[0036] Example 2 The manufacturing method for high modulus of elasticity and low shrinkage yarn, specifically the steps involved, is as follows: The yarn extruded from the spinneret is pre-cooled by sequentially passing through a slow-cooling region with a height of 95 mm and a windless region with a height of 45 mm, before entering a cooling region where it is cooled and molded to produce a high modulus of elasticity and low shrinkage yarn.

[0037] The cooling area consists of a continuous cooling area A and cooling area B, running from top to bottom, and a cylindrical cooling tube C connected below cooling area B.

[0038] Cooling area A is a cylindrical air duct with a height of 460 mm. Its air outlet is located in the upper left and is on the inside, blowing air from the outside to the inside, and the direction of airflow is perpendicular to the direction of travel of the yarn bundle. Inside cooling area A is a ring-blowing filter core with an inner diameter of 270 mm, and on the outside is a sleeve I that is larger in diameter than the ring-blowing filter core and coaxial with it, forming an annular cavity I between the ring-blowing filter core and sleeve I. The top and bottom of the annular cavity I are sealed and serve as the inflow path for the cooling air. The distance between the inner wall of sleeve I and the outer wall of the ring-blowing filter core (i.e., the width of the annular cavity I) is 1 cm.

[0039] Cooling area B is a cylindrical air duct with a height of 390 mm. The air outlet of cooling area B is located on the upper left side and is at the bottom end, blowing air from top to bottom, with the airflow direction parallel to the direction of the thread bundle's movement. Inside cooling area B is a cylindrical tube with an inner diameter of 220 mm, and on the outside is a coaxial sleeve II with a larger diameter than the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II to serve as the airflow path for cooling. The top of the annular cavity II is sealed, and the distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 1 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected.

[0040] The cylindrical cooling tube C has a height of 690 mm and an inner diameter of 310 mm.

[0041] Here, the ambient temperature is 35°C, the air temperature in cooling area A is 15°C higher than the ambient temperature, and the air temperature in cooling area B is 10°C lower than the ambient temperature. The spinning speed is 3000 m / min, and the winding speed is 5800 m / min.

[0042] The obtained high modulus of elasticity and low shrinkage yarn had a single fiber fineness of 4.71 dtex, a single fiber count of 240 f, an initial modulus of elasticity of 105 cN / dtex, and a dimensional stability index of 8.50%.

[0043] Example 3 The manufacturing method for high modulus of elasticity and low shrinkage yarn, specifically the steps involved, is as follows: The yarn extruded from the spinneret is pre-cooled by sequentially passing through a slow-cooling region with a height of 97 mm and a windless region with a height of 47 mm, before entering a cooling region where it is cooled and molded to produce a high modulus of elasticity and low shrinkage yarn.

[0044] The cooling area consists of a continuous cooling area A and cooling area B, running from top to bottom, and a cylindrical cooling tube C connected below cooling area B.

[0045] Cooling area A is a cylindrical air duct with a height of 445 mm. Its air outlet is located in the upper left and is on the inside, blowing air from the outside to the inside, and the direction of airflow is perpendicular to the direction of travel of the yarn bundle. Inside cooling area A is a ring-blowing filter core with an inner diameter of 272 mm, and on the outside is a sleeve I that is larger in diameter than the ring-blowing filter core and coaxial with it, forming an annular cavity I between the ring-blowing filter core and sleeve I. The top and bottom of the annular cavity I are sealed and serve as the inflow path for the cooling air. The distance between the inner wall of sleeve I and the outer wall of the ring-blowing filter core (i.e., the width of the annular cavity I) is 1.2 cm.

[0046] Cooling area B is a cylindrical air duct with a height of 395 mm. The air outlet of cooling area B is located on the upper left side and is at the bottom end, blowing air from top to bottom, with the airflow direction parallel to the direction of the thread bundle's movement. Inside cooling area B is a cylindrical tube with an inner diameter of 222 mm, and on the outside is a coaxial sleeve II with a larger diameter than the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II to serve as the airflow path for cooling. The top of annular cavity II is sealed, and the distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 1.2 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected.

[0047] The cylindrical cooling tube C has a height of 695 mm and an inner diameter of 312 mm.

[0048] Here, the ambient temperature is 36°C, the air temperature in cooling area A is 5°C higher than the ambient temperature, and the air temperature in cooling area B is 11°C lower than the ambient temperature. The spinning speed is 3100 m / min, and the winding speed is 5900 m / min.

[0049] The obtained high modulus of elasticity and low shrinkage yarn had a single fiber fineness of 4.81 dtex, a single fiber count of 235 f, an initial modulus of elasticity of 106 cN / dtex, and a dimensional stability index of 8.20%.

[0050] Example 4 The manufacturing method for high modulus of elasticity and low shrinkage yarn, specifically the steps involved, is as follows: The yarn extruded from the spinneret is pre-cooled by sequentially passing through a slow-cooling region with a height of 99 mm and a windless region with a height of 49 mm, before entering a cooling region where it is cooled and molded to produce a high modulus of elasticity and low shrinkage yarn.

[0051] The cooling area consists of a continuous cooling area A and cooling area B, running from top to bottom, and a cylindrical cooling tube C connected below cooling area B.

[0052] Cooling area A is a cylindrical air duct with a height of 450 mm. Its air outlet is located in the upper left and is on the inside, blowing air from the outside to the inside, and the direction of airflow is perpendicular to the direction of travel of the yarn bundle. Inside cooling area A is a ring-blowing filter core with an inner diameter of 274 mm, and on the outside is a sleeve I that is larger in diameter than the ring-blowing filter core and coaxial with it, forming an annular cavity I between the ring-blowing filter core and sleeve I. The top and bottom of the annular cavity I are sealed and serve as the inflow path for the cooling air. The distance between the inner wall of sleeve I and the outer wall of the ring-blowing filter core (i.e., the width of the annular cavity I) is 1.4 cm.

[0053] Cooling area B is a cylindrical air duct with a height of 400 mm. The air outlet of cooling area B is located on the upper left side and is at the bottom end, blowing air from top to bottom, with the airflow direction parallel to the direction of the thread bundle's movement. Inside cooling area B is a cylindrical tube with an inner diameter of 224 mm, and on the outside is a coaxial sleeve II with a larger diameter than the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II to serve as the airflow path for cooling. The top of the annular cavity II is sealed, and the distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 1.4 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected.

[0054] The cylindrical cooling tube C has a height of 700 mm and an inner diameter of 314 mm.

[0055] Here, the ambient temperature is 37°C, the air temperature in cooling area A is 7°C higher than the ambient temperature, and the air temperature in cooling area B is 12°C lower than the ambient temperature. The spinning speed is 3200 m / min, and the winding speed is 6000 m / min.

[0056] The obtained high modulus of elasticity and low shrinkage yarn had a single fiber fineness of 4.91 dtex, a single fiber count of 230 f, an initial modulus of elasticity of 107 cN / dtex, and a dimensional stability index of 7.80%.

[0057] Example 5 The manufacturing method for high modulus of elasticity and low shrinkage yarn, specifically the steps involved, is as follows: The yarn extruded from the spinneret is pre-cooled by sequentially passing through a slow-cooling region with a height of 100 mm and a windless region with a height of 51 mm, before entering a cooling region where it is cooled and molded to produce a high modulus of elasticity and low shrinkage yarn.

[0058] The cooling area consists of a continuous cooling area A and cooling area B, running from top to bottom, and a cylindrical cooling tube C connected below cooling area B.

[0059] Cooling area A is a cylindrical air duct with a height of 455 mm. Its air outlet is located in the upper left and is on the inside, blowing air from the outside to the inside, and the direction of airflow is perpendicular to the direction of travel of the yarn bundle. Inside cooling area A is a ring-blowing filter core with an inner diameter of 275 mm, and on the outside is a coaxial sleeve I with a larger diameter than the ring-blowing filter core, forming an annular cavity I between the ring-blowing filter core and sleeve I. The top and bottom of the annular cavity I are sealed and serve as the inflow path for the cooling air. The distance between the inner wall of sleeve I and the outer wall of the ring-blowing filter core (i.e., the width of the annular cavity I) is 1.5 cm.

[0060] Cooling area B is a cylindrical air duct with a height of 405 mm. The air outlet of cooling area B is located on the upper left side and is at the bottom end, blowing air from top to bottom, with the airflow direction parallel to the direction of the thread bundle's movement. Inside cooling area B is a cylindrical tube with an inner diameter of 225 mm, and on the outside is a coaxial sleeve II with a larger diameter than the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II to serve as the airflow path for cooling. The top of the annular cavity II is sealed, and the distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 1.5 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected.

[0061] The cylindrical cooling tube C has a height of 705 mm and an inner diameter of 315 mm.

[0062] Here, the ambient temperature is 38°C, the air temperature in cooling area A is 10°C higher than the ambient temperature, and the air temperature in cooling area B is 13°C lower than the ambient temperature. The spinning speed is 3300 m / min, and the winding speed is 6100 m / min.

[0063] The obtained high modulus of elasticity and low shrinkage yarn had a single fiber fineness of 5.14 dtex, a single fiber count of 220 f, an initial modulus of elasticity of 108 cN / dtex, and a dimensional stability index of 7.50%.

[0064] Example 6 The manufacturing method for high modulus of elasticity and low shrinkage yarn, specifically the steps involved, is as follows: The yarn extruded from the spinneret is pre-cooled by sequentially passing through a slow-cooling region at a height of 103 mm and a windless region at a height of 53 mm, before entering a cooling region where it is cooled and molded to produce a high modulus of elasticity and low shrinkage yarn.

[0065] The cooling area consists of a continuous cooling area A and cooling area B, running from top to bottom, and a cylindrical cooling tube C connected below cooling area B.

[0066] Cooling region A is a cylindrical air duct with a height of 458 mm. Its air outlet is located in the upper left and is on the inside, blowing air from the outside to the inside, and the direction of airflow is perpendicular to the direction of travel of the yarn bundle. Inside cooling region A is a ring-blowing filter core with an inner diameter of 278 mm, and on the outside is a sleeve I that is larger in diameter than the ring-blowing filter core and coaxial with it, forming an annular cavity I between the ring-blowing filter core and sleeve I. The top and bottom of the annular cavity I are sealed and serve as the inflow path for the cooling air. The distance between the inner wall of sleeve I and the outer wall of the ring-blowing filter core (i.e., the width of the annular cavity I) is 1.8 cm.

[0067] Cooling area B is a cylindrical air duct with a height of 408 mm. The air outlet of cooling area B is located on the upper left side and is at the bottom end, blowing air from top to bottom, with the airflow direction parallel to the direction of the thread bundle's movement. Inside cooling area B is a cylindrical tube with an inner diameter of 228 mm, and on the outside is a coaxial sleeve II with a larger diameter than the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II to serve as the airflow path for cooling. The top of the annular cavity II is sealed, and the distance between the inner wall of sleeve II and the outer wall of the cylindrical tube (i.e., the width of annular cavity II) is 1.8 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected.

[0068] The cylindrical cooling tube C has a height of 708 mm and an inner diameter of 316 mm.

[0069] Here, the ambient temperature is 40°C, the air temperature in cooling area A is 10°C higher than the ambient temperature, and the air temperature in cooling area B is 14°C lower than the ambient temperature. The spinning speed is 3350 m / min, and the winding speed is 6150 m / min.

[0070] The obtained high modulus of elasticity and low shrinkage yarn had a single fiber fineness of 5.38 dtex, a single fiber count of 210 f, an initial modulus of elasticity of 109.5 cN / dtex, and a dimensional stability index of 7.20%. [Explanation of Symbols]

[0071] 1- Spinning pack, 2- Rear heater, 3- Airless zone, 4- Cooling zone A, 5- Cooling zone B, 6- Cylindrical cooling cylinder C, 7- Air outlet for cooling zone A, 8- Air outlet for cooling zone B, 9- Air outlet for cylindrical cooling cylinder C, 10- Ring-blowing filter core, 11- Sleeve I, 12- Ring cavity I.

Claims

1. The yarn bundle extruded from the spinneret is pre-cooled by sequentially passing through a slow-cooling region and a windless region, then enters a cooling region where it is cooled and shaped to obtain a high modulus of elasticity and low shrinkage yarn. The cooling region includes a continuous cooling region A, a cooling region B, and a cylindrical passage C connected below cooling region B, running from top to bottom. Cooling area A is a cylindrical air duct, with the air outlet located on the inside and the airflow direction perpendicular to the direction of travel of the yarn bundle. Cooling area B is a cylindrical air duct with an air outlet located at its lower end, and the airflow direction is parallel to the direction in which the yarn bundle travels. The air temperature in cooling area A is 5 to 15°C higher than the ambient temperature, at 40 to 50°C. The air temperature in cooling area B is 10-15°C lower than the ambient temperature. The inner diameter of cooling region A is larger than the inner diameter of cooling region B, and the inner diameter of cooling region A is smaller than the inner diameter of cylindrical passage C. A method for producing a high modulus of elasticity and low shrinkage yarn, characterized by the above.

2. The ambient temperature is 35-40°C. A method for producing a high modulus of elasticity and low shrinkage yarn according to feature 1.

3. A ring-blowing filter core is installed inside cooling region A. Outside the cooling region A, a sleeve I with a diameter larger than the ring-blowing filter core is provided coaxially with the ring-blowing filter core. An annular cavity I is formed between the ring-blowing filter core and the sleeve I, allowing cooling air to enter. The method for producing a high modulus of elasticity and low shrinkage yarn according to feature 2.

4. The distance between the inner wall of sleeve I and the outer wall of the ring-blown filter core is 1 to 2 cm. A method for producing a high modulus of elasticity and low shrinkage yarn according to feature 3.

5. Inside cooling area B, a cylindrical tube is installed. Outside the cooling region B, a sleeve II with a diameter larger than the cylindrical tube is provided coaxially with the cylindrical tube. An annular cavity II is formed between the cylindrical tube and sleeve II, allowing cooling air to enter. 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 tube is 1 to 2 cm. The bottom of sleeve I and the top of sleeve II are fixedly connected. The method for producing a high modulus of elasticity and low shrinkage yarn according to feature 4.

6. The inner diameter of the ring-blown filter core in cooling region A is 270-280 mm. The inner diameter of the cylindrical tube in cooling region B is 220-230 mm. The inner diameter of the cylindrical passage C is 310 to 320 mm. A method for producing a high modulus of elasticity and low shrinkage yarn according to feature 5.

7. The height of the slow-cooling region is 95-105 mm. The height of the windless area is 45-55 mm. The height of cooling area A is 440-460 mm. The height of cooling area B is 390-410 mm. The height of the cylindrical passage C is 690 to 710 mm. The method for producing a high modulus of elasticity and low shrinkage yarn according to feature 6.

8. High modulus low shrinkage yarn has a single fiber fineness of 4.71 to 5.65 dtex and a single fiber count of 200 to 240 strands. A method for producing a high modulus of elasticity and low shrinkage yarn according to feature 7.

9. The spinning speed is 3000–3400 m / min. The winding speed is 5800-6200 m / min. The method for producing a high modulus of elasticity and low shrinkage yarn according to feature 8.

10. The method for producing a high modulus, low shrinkage yarn according to claim 9, characterized in that the high modulus, low shrinkage yarn has an initial modulus of elasticity of 105 to 110 cN / dtex and a dimensional stability index of 7 to 8.5%.

Images