Method for producing high-modulus low-shrinkage yarns

Abstract

A method for producing high-modulus low-shrinkage yarns. Yarns extruded from a spinneret sequentially pass through a slow cooling zone and a windless zone (3) for pre-cooling, and then enter cooling zones for cooling and forming to obtain high-modulus low-shrinkage yarns. The cooling zones comprise, from top to bottom, a cooling zone A (4) and a cooling zone B (5) which are connected and a cylindrical channel C (6) connected below the cooling zone B (5). The cooling zone A (4) is a cylindrical air duct, and has an air outlet located inside and the blowing direction perpendicular to the running direction of a yarn bundle. The cooling zone B (5) is a cylindrical air duct, and has an air outlet located at the lower end and the blowing direction parallel to the running direction of the yarn bundle. According to the method for producing high-modulus low-shrinkage yarns, the ring-blowing cooling zone B (5) is added, air is blown vertically downwards, and a "vacuumizing" effect can be formed, so that hot air in the cooling area A (4) flows downwards, making the hot air easily discharged, reducing the impact of hot air on primary yarns.

Description

A method for producing high modulus low shrinkage wire Technical Field

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

[0002] Industrial high modulus low shrinkage yarn is mainly used in tire cord, which is the skeleton material of automobile tires. It needs to have high strength and good dimensional stability. Its physical properties require high strength, high modulus, and low dry heat shrinkage. The dimensional stability is affected by the constant load elongation and dry heat shrinkage performance. The literature (Development of high modulus low shrinkage polyester industrial yarn. Synthetic Fiber Industry, 2013, 36(1): 67-69.) records that in order to achieve a high modulus of polyester industrial yarn, the production process must have a high spinning speed. In order to prevent the undrawn yarn from crystallizing in the rapid cold zone, the production of high modulus low shrinkage products generally uses hot air above 40°C for cooling. At the same time, porous yarn is required to reduce the single filament fineness, so that the yarn bundle is cooled evenly and the "skin-core" structure is avoided. In the existing production process, the density of hot air is lower than the density of the external ambient air, and the hot air is not easy to be discharged. The fluidity of the hot air cooling wind becomes worse, which affects the cooling of the unstretched fibers. At the same time, the hot air is not easy to be discharged downward and will move upward to the spinneret surface, affecting the formation of spun fibers. The spun yarn is prone to bends and sticking to the plate, resulting in poor spinnability and affecting the improvement of the dimensional stability of high-modulus low-shrinkage products.

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

[0004] Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for producing high modulus low shrinkage yarn;

[0006] To achieve the above object, the present invention adopts the following scheme:

[0007] A method for producing high modulus low shrinkage yarn, wherein the yarn is extruded from a spinneret, sequentially passed through a slow cooling zone and a windless zone for pre-cooling, and then enters a cooling zone for cooling and forming to produce the high modulus low shrinkage yarn;

[0008] The cooling zone includes, from top to bottom, the connected cooling zone A and cooling zone B, and a cylindrical corridor C connected below the cooling zone B;

[0009] Cooling zone A is a cylindrical air duct with the air outlet located inside. Air blows from outside to inside, and the blowing direction is perpendicular to the running direction of the tow.

[0010] Cooling zone B is a cylindrical air duct with the air outlet at the lower end, blowing air from top to bottom, and the blowing direction is parallel to the running direction of the tow;

[0011] The blowing temperature of cooling zone A is 5-15°C higher than the ambient temperature, at 40-50°C, and the blowing temperature of cooling zone B is 10-15°C lower than the ambient temperature;

[0012] The inner diameter of the cooling zone A is larger than the inner diameter of the cooling zone B, and the inner diameter of the cooling zone A is smaller than the inner diameter of the cylindrical corridor C.

[0013] As the preferred technical solution:

[0014] In the high modulus low shrinkage yarn production method described above, the ambient temperature is 35-40°C, and the air supply temperature of the filament production environment is about 25°C. However, since there are many heating devices in the production environment and the melt carries high-temperature melt heat, the actual production environment temperature (room temperature) is 35-40°C.

[0015] In the HMLS yarn production method described above, a ring-blown filter element is disposed within cooling zone A. A sleeve I, which has a larger diameter than and is coaxial with the ring-blown filter element, is disposed outside cooling zone A. An annular cavity is formed between the ring-blown filter element and sleeve I, which allows cooling air to enter. The annular cavity I is connected and sealed from the outside. During operation, cooling air enters through the air inlet duct, fills the annular cavity I, and then penetrates the ring-blown filter element to cool the yarn passing through the center of the ring-blown filter element.

[0016] In the above-mentioned method for producing high-modulus low-shrinkage yarn, the distance between the inner wall of the sleeve I and the outer wall of the ring-blown filter element (ie, the width of the annular cavity I) is 1 to 2 cm.

[0017] As described above, a high-modulus low-shrinkage wire production method is provided, wherein a cylindrical tube is provided inside the cooling zone B, and a sleeve II having a diameter larger than that of the cylindrical tube and coaxial with the cylindrical tube is provided 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 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 tube (i.e., the width of the annular cavity II) is 1 to 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 duct and fills the annular cavity II, and then enters the corridor through the bottom of the annular cavity II; in addition, it can be further preferred that the sleeve I and the sleeve II are integrally formed parts.

[0018] In the high-modulus low-shrinkage yarn production method described above, the inner diameter of the ring-blown 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 corridor C is 310-320 mm.

[0019] As described above, in a method for producing high-modulus, low-shrinkage yarn, 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 corridor C is 690-710 mm. The principle of the high-modulus, low-shrinkage production process is to obtain products with high modulus and high dimensional stability through high-speed spinning and extremely rapid cooling. Therefore, the slow cooling zone and the windless zone become smaller, and the degree of extreme cooling is enhanced, which can improve the modulus and dimensional stability of the product.

[0020] The high modulus low shrinkage yarn production method as described above has a single yarn fineness of 4.71 to 5.65 dtex and a fiber number of 200 to 240 f.

[0021] The above-mentioned method for producing high-modulus low-shrinkage yarn has a spinning speed (i.e., a roller speed) of 3000-3400 m / min and a winding speed of 5800-6200 m / min. After cooling and forming, winding is performed. The prior art produces high-strength low-shrinkage yarn with a roller speed of 2600-3000 m / min and a winding speed of 5200-5400 m / min. In the prior art, the roller speed and winding speed can be higher for producing high-modulus low-shrinkage yarn, but the increase in speed will increase the number of broken ends and the degradation of the appearance of the hairy yarn. After the improved cooling of the present invention, the number of holes can be reduced and the single filament fineness is larger, so the anti-drafting performance of the yarn bundle is better, and it can be produced at a higher speed and draw ratio. The higher speed can improve the modulus and dimensional stability of the product, and the higher draw ratio can improve the strength of the product.

[0022] A method for producing a high-modulus low-shrinkage yarn as described above, wherein the high-modulus low-shrinkage yarn has an initial modulus of 105 to 110 cN / dtex and a dimensional stability of 7 to 8.5%;

[0023] Taking the prior art 1000D product as an example, the actual fineness is 1130dtex, the number of holes is 300 to 360 holes, and the single filament fineness is 3.14 to 3.77dtex. The method of the present invention increases the cooling airflow momentum, solves the problem of uneven cooling of the single filament caused by excessive single filament fineness, and can improve the number of holes to 200 to 240 holes. The actual fineness remains unchanged, and the single filament fineness becomes 4.71 to 5.65dtex. The single filament fineness is improved, and in the filament production process, there can be a higher speed increase space, that is, while maintaining the spinning condition and appearance, the spinning speed and draft ratio can be better improved. When the production process remains unchanged and the number of holes is reduced alone, the product modulus and dimensional stability are basically unchanged. The present invention solves the problem of uneven cooling after the hole speed is reduced by improving the cooling air efficiency, thereby increasing the spinning speed and improving the product modulus and dimensional stability.

[0024] The principle of the present invention is:

[0025] Cooling zone B provides low-temperature cooling air at 20-25°C, blowing parallel to the direction of the tow's travel. This serves the purpose of providing a secondary cooling effect on the tow, ensuring uniform cooling throughout the tow. It also serves the purpose of driving the annular airflow in cooling zone A downward. The principle is that the lower air temperature in cooling zone B lowers the air temperature in cooling zone A. The lower the air temperature, the greater the density, making it easier for the annular airflow in cooling zone A to flow downward. Simultaneously, cooling zone B blows air vertically downward, creating a "vacuuming" effect, forcing the hot air in cooling zone A to flow downward. This improves the fluidity of the air in cooling zone A, enhancing its slow cooling effect on the undrawn tow and preventing the upward movement of hot air from interfering with the extrusion of nascent fibers from the spinneret. In the prior art, cooling zone A is directly connected to the tunnel (i.e., there is no cooling zone B), resulting in poor heat dissipation. Furthermore, external wind can easily affect the swaying of the tow within the annular airflow, causing uncooled filaments to "fight" with each other, leading to breakage and fuzzy fibers.

[0026] The inner diameter of the ring-blowing filter element in cooling zone A is 270-280 mm, the inner diameter of the cylindrical tube in cooling zone B is 220-230 mm, and the inner diameter of the cylindrical corridor C is 310-320 mm; the inner diameter of the cylindrical corridor C is larger than the inner diameter of the ring-blowing filter element in cooling zone A, and the inner diameter of the ring-blowing filter element in cooling zone A is larger than the inner diameter of the cylindrical tube of cooling air B; the interior of the ring-blowing filter element is defined as zone A, the interior of the cylindrical tube is defined as zone B, and the interior of the cylindrical corridor C is defined as zone C; the cooling air flow rate of zone A = the cooling air flow rate of zone B Air flow rate, the formula for air flow rate = wind speed V × cross-sectional area × time. The cross-sectional area is proportional to the pipe diameter. That is, per unit time, because the inner diameter of the ring-blown filter element in cooling zone A is larger than the inner diameter of the cylindrical pipe for cooling air B, when the ring-blown air in cooling zone A flows downward, the wind speed in zone B is greater than that in zone A. This method not only improves the fluidity of the hot air in zone A, but more importantly, the increased wind speed in zone B produces a stress-stretching effect on the tow, leaving space for the tow to stretch later, which can reduce the generation of tow fuzz. At the same time, it improves the modulus and dimensional stability of the tow. Beneficial effects

[0027] (1) A high modulus low shrinkage yarn production method of the present invention adds a ring-blowing cooling zone B, which blows air vertically downward to form a "vacuuming" effect, so that the hot air in the cooling zone A flows downward, making it easy to discharge the hot air, thereby reducing the impact of the hot air on the spun yarn;

[0028] (2) In the prior art, due to poor cooling performance, high modulus low shrinkage products are generally produced in porous specifications to meet fiber cooling conditions, such as 1000D / 336f, 1200D / 384f, etc. Although the porous yarn meets the existing cooling production needs, the fatigue resistance of the porous yarn deteriorates when it is used for tires after dipping in the late stage. Therefore, in a high modulus low shrinkage yarn production method of the present invention, hot air is easily discharged, so there is no need to deliberately design the product as a porous filament. Less porous yarn can be directly produced to increase the single yarn fineness, such as 1000D / 192f, 1200D / 244f, etc., so that the fatigue resistance of the tire product is improved when it is used for tires after dipping in the late stage. For example: in the prior art, taking 1000D products as an example, the number of holes is 300 to 380 holes. The present invention enhances the cooling effect by improving the fluidity of the cooling air, and can reduce the number of holes of the 1000D product to 200 to 240 holes, so that the product has a better strong retention effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a structural diagram of a device used in a method for producing high modulus low shrinkage yarn according to the present invention;

[0030] FIG2 is a schematic diagram of two wind directions in a method for producing high modulus low shrinkage yarn according to the present invention;

[0031] FIG3 is a partial enlarged view of a device used in a method for producing high modulus low shrinkage yarn according to the present invention;

[0032] Among them, 1-spinning box, 2-afterheater, 3-windless zone, 4-cooling zone A, 5-cooling zone B, 6-cylindrical corridor C, 7-air supply port of cooling zone A, 8-air supply port of cooling zone B, 9-air dispersing port of cylindrical corridor C, 10-ring-blown filter element, 11-sleeve I, 12-annular cavity I. DETAILED DESCRIPTION

[0033] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, 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 fall equally within the scope limited by the appended claims of the application.

[0034] The testing method adopted in the present invention is as follows:

[0035] Initial modulus: Utilizing a STATIMAT 4U instrument, the specimens were stretched to fracture using an automatic tensor-extensometer under test conditions. The initial modulus was automatically calculated by a computer. Test conditions: nominal grip length: 500 mm ± 1 mm, test speed: 500 mm / min, pretension: 0.05 ± 0.01 cN / dtex, number of tests: 5 times per sample.

[0036] Dimensional stability: Referring to GB / T 16604-2017, dimensional stability is the sum of the fiber's elongation at a load of 4.0 cN / dtex and its dry heat shrinkage.

[0037] Using a STATIMAT 4U instrument, specimens were stretched to fracture using an automatic tensile tester under test conditions. The elongation at a load of 4.0 cN / dtex was automatically calculated by a computer. Test conditions: nominal clamp length: 500 mm ± 1 mm, test speed: 500 mm / min, preload: 0.05 ± 0.01 cN / dtex, and five tests per sample. Dry heat shrinkage refers to the percentage of length shrinkage before and after hot air treatment of a 250 mm long yarn using a Lanjing TST510 under specified preload (0.05 ± 0.01 cN / dtex), temperature (177°C), and time (10 minutes). The sum of the elongation at a load of 4.0 cN / dtex and the dry heat shrinkage yields the dimensional stability.

[0038] Example 1

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

[0040] As shown in Figure 1, the filaments extruded from the spinneret in the spinning manifold 1 enter the post-heater 2, and then pass through the slow cooling zone with a height of 105 mm and the windless zone 3 with a height of 55 mm for pre-cooling, and then enter the cooling zone for cooling and forming to produce high modulus low shrinkage yarn;

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

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

[0043] Cooling zone B5 is a cylindrical air duct with a height of 410 mm. The air supply port 8 of cooling zone B is located on the upper left side, and the air outlet is located at the lower end. Air is blown from top to bottom, and the blowing direction is parallel to the direction of filament travel. A cylindrical tube with an inner diameter of 230 mm is provided inside cooling zone B5. A sleeve II with a diameter greater than and coaxial with the cylindrical tube is provided outside cooling zone B5. An annular cavity II is formed between the cylindrical tube and sleeve II. Annular cavity II is used for the entry of cooling air. The top of annular cavity II 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 2 cm. The bottom of sleeve I is fixedly connected to the top of sleeve II.

[0044] The height of the cylindrical corridor C 6 is 710 mm and the inner diameter is 320 mm; the cooling air is dispersed through the air dispersing port 9 of the cylindrical corridor C;

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

[0046] The obtained high modulus low shrinkage yarn has a single yarn fineness of 5.65 dtex, a fiber number of 200f, an initial modulus of 110 cN / dtex, and a dimensional stability of 7%.

[0047] Comparative Example 1

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

[0049] The obtained high modulus low shrinkage yarn has a single yarn fineness of 3.14 dtex, a fiber number of 360f, an initial modulus of 97 cN / dtex, and a dimensional stability of 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 of the present invention, and can only be achieved by increasing the number of spinnerets. However, as the number of spinnerets increases, the spinning stability at high speed deteriorates. In order to take into account the spinning conditions, the spinning speed can only be reduced. Therefore, the initial modulus in the comparative example is relatively low and the dimensional stability is relatively large.

[0051] Example 2

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

[0053] The filaments extruded from the spinneret 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, and then enter the cooling zone for cooling and forming to produce high modulus low shrinkage filaments.

[0054] The cooling zone includes, from top to bottom, the connected cooling zone A and cooling zone B, and a cylindrical corridor C connected below the 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 on the upper left, and the air outlet is located on the inside. Air blows from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow. A ring-blown filter element with an inner diameter of 270 mm is provided inside cooling zone A. A sleeve I with a diameter larger than that of the ring-blown filter element and coaxial with the ring-blown filter element is provided on the outside of cooling zone A. An annular cavity is formed between the ring-blown 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-blown 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 at the upper left, and the air outlet is located at the lower end. Air blows from top to bottom, and the blowing direction is parallel to the direction of filament travel. A cylindrical tube with an inner diameter of 220 mm is provided inside cooling zone B. A sleeve II with a diameter larger than the cylindrical tube and coaxial with the cylindrical tube is provided on the outside of cooling zone B. An annular cavity II is formed between the cylindrical tube and sleeve II. Annular cavity II is used for cooling air to enter. The top of annular cavity II 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 cm. The bottom of sleeve I is fixedly connected to the top of sleeve II.

[0057] The height of cylindrical corridor C is 690 mm and the inner diameter is 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 3000m / min, and the winding speed is 5800m / min.

[0059] The obtained high modulus low shrinkage yarn has a single yarn fineness of 4.71 dtex, a fiber number of 240f, an initial modulus of 105 cN / dtex, and a dimensional stability of 8.50%.

[0060] Example 3

[0061] A method for producing high modulus low shrinkage wire, the specific process is as follows:

[0062] The filaments extruded from the spinneret pass through a slow cooling zone with a height of 97 mm and a windless zone with a height of 47 mm for pre-cooling, and then enter the cooling zone for cooling and forming to produce high modulus low shrinkage filaments.

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

[0064] Cooling zone A is a cylindrical air duct with a height of 445 mm. The air supply port of cooling zone A is located on the upper left, and the air outlet is located on the inside. Air blows from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow. A ring-blown filter element with an inner diameter of 272 mm is provided inside cooling zone A. A sleeve I with a diameter larger than that of the ring-blown filter element and coaxial with the ring-blown filter element is provided on the outside of cooling zone A. An annular cavity is formed between the ring-blown 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 cooling air to enter. The distance between the inner wall of the sleeve I and the outer wall of the ring-blown filter element (i.e., the width of the annular cavity I) is 1.2 cm.

[0065] Cooling zone B is a cylindrical air duct with a height of 395 mm. The air supply port of cooling zone B is located at the upper left, and the air outlet is located at the lower end. Air blows from top to bottom, and the blowing direction is parallel to the direction of filament travel. A cylindrical tube with an inner diameter of 222 mm is provided inside cooling zone B. A sleeve II with a diameter larger than the cylindrical tube and coaxial with the cylindrical tube is provided on the outside of cooling zone B. An annular cavity II is formed between the cylindrical tube and sleeve II. Annular cavity II is used for the entry of cooling air. The top of annular cavity II 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 1.2 cm. The bottom of sleeve I is fixedly connected to the top of sleeve II.

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

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

[0068] The obtained high modulus low shrinkage yarn has a single yarn fineness of 4.81 dtex, a fiber number of 235f, an initial modulus of 106 cN / dtex, and a dimensional stability of 8.20%.

[0069] Example 4

[0070] A method for producing high modulus low shrinkage yarn, the specific process is as follows:

[0071] The filaments extruded from the spinneret pass through a slow cooling zone with a height of 99 mm and a windless zone with a height of 49 mm for pre-cooling, and then enter the cooling zone for cooling and forming to produce high modulus low shrinkage filaments.

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

[0073] Cooling zone A is a cylindrical air duct with a height of 450 mm. The air supply port of cooling zone A is located on the upper left, and the air outlet is located on the inside. Air blows from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow. A ring-blown filter element with an inner diameter of 274 mm is provided inside cooling zone A. A sleeve I with a diameter larger than that of the ring-blown filter element and coaxial with the ring-blown filter element is provided on the outside of cooling zone A. An annular cavity is formed between the ring-blown 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 cooling air to enter. The distance between the inner wall of the sleeve I and the outer wall of the ring-blown filter element (i.e., the width of the annular cavity I) is 1.4 cm.

[0074] Cooling zone B is a cylindrical air duct with a height of 400 mm. The air supply port of cooling zone B is located at the upper left, and the air outlet is at the lower end. Air blows from top to bottom, and the blowing direction is parallel to the direction of filament travel. A cylindrical tube with an inner diameter of 224 mm is installed inside cooling zone B. A sleeve II with a larger diameter than the cylindrical tube and coaxial with the cylindrical tube is installed outside cooling zone B. An annular cavity II is formed between the cylindrical tube and sleeve II. Annular cavity II is used for the entry of cooling air. The top of annular cavity II 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 1.4 cm. The bottom of sleeve I is fixedly connected to the top of sleeve II.

[0075] The height of cylindrical corridor C is 700 mm and the inner diameter is 314 mm;

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

[0077] The obtained high modulus low shrinkage yarn has a single yarn fineness of 4.91 dtex, a fiber number of 230f, an initial modulus of 107 cN / dtex, and a dimensional stability of 7.80%.

[0078] Example 5

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

[0080] The filaments extruded from the spinneret pass through a slow cooling zone with a height of 100 mm and a windless zone with a height of 51 mm for pre-cooling, and then enter the cooling zone for cooling and forming to produce high modulus low shrinkage filaments.

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

[0082] Cooling zone A is a cylindrical air duct with a height of 455mm. The air supply port of cooling zone A is located on the upper left, and the air outlet is located on the inside. Air blows from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow. A ring-blown filter element with an inner diameter of 275mm is provided inside cooling zone A. A sleeve I with a diameter larger than that of the ring-blown filter element and coaxial with the ring-blown filter element is provided on the outside of cooling zone A. An annular cavity is formed between the ring-blown 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 cooling air to enter. The distance between the inner wall of the sleeve I and the outer wall of the ring-blown filter element (i.e., the width of the annular cavity I) is 1.5cm.

[0083] Cooling zone B is a cylindrical air duct with a height of 405 mm. The air supply port of cooling zone B is located at the upper left, and the air outlet is located at the lower end. Air blows from top to bottom, and the blowing direction is parallel to the direction of filament travel. A cylindrical tube with an inner diameter of 225 mm is provided inside cooling zone B. A sleeve II with a diameter larger than the cylindrical tube and coaxial with the cylindrical tube is provided on the outside of cooling zone B. An annular cavity II is formed between the cylindrical tube and sleeve II. Annular cavity II is used for cooling air to enter. The top of annular cavity II 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 1.5 cm. The bottom of sleeve I is fixedly connected to the top of sleeve II.

[0084] The height of cylindrical corridor C is 705mm and the inner diameter is 315mm;

[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 3300m / min, and the winding speed is 6100m / min.

[0086] The obtained high modulus low shrinkage yarn has a single yarn fineness of 5.14 dtex, a fiber number of 220f, an initial modulus of 108 cN / dtex, and a dimensional stability of 7.50%.

[0087] Example 6

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

[0089] The filaments extruded from the spinneret pass through a slow cooling zone with a height of 103 mm and a windless zone with a height of 53 mm for pre-cooling, and then enter the cooling zone for cooling and forming to produce high modulus low shrinkage filaments.

[0090] The cooling zone includes, from top to bottom, the connected cooling zone A and cooling zone B, and a cylindrical corridor C connected below the 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 on the upper left, and the air outlet is located on the inside. Air blows from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow. A ring-blown filter element with an inner diameter of 278 mm is provided inside cooling zone A. A sleeve I with a diameter larger than that of the ring-blown filter element and coaxial with the ring-blown filter element is provided on the outside of cooling zone A. An annular cavity is formed between the ring-blown 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-blown 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 at the upper left, and the air outlet is located at the lower end. Air blows from top to bottom, and the blowing direction is parallel to the direction of filament travel. A cylindrical tube with an inner diameter of 228 mm is provided inside cooling zone B. A sleeve II with a diameter larger than the cylindrical tube and coaxial with the cylindrical tube is provided on the outside of cooling zone B. An annular cavity II is formed between the cylindrical tube and sleeve II. Annular cavity II is used for the entry of cooling air. The top of annular cavity II 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 1.8 cm. The bottom of sleeve I is fixedly connected to the top of sleeve II.

[0093] The height of cylindrical corridor 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 3350m / min, and the winding speed is 6150m / min.

[0095] The obtained high modulus low shrinkage yarn has a single yarn fineness of 5.38 dtex, a fiber number of 210f, an initial modulus of 109.5 cN / dtex, and a dimensional stability of 7.20%.

Claims

1. A method for producing high modulus low shrinkage wire, characterized in that: The filaments extruded from the spinneret are pre-cooled in the slow cooling zone and the windless zone in sequence, and then enter the cooling zone for cooling and molding to obtain high modulus low shrinkage filaments; The cooling zone includes, from top to bottom, the connected cooling zone A and cooling zone B and a cylindrical corridor C connected below the cooling zone B; The cooling zone A is a cylindrical air cylinder, the air outlet is located inside, and the blowing direction is perpendicular to the running direction of the tow; The cooling zone B is a cylindrical air cylinder, the air outlet is located at the lower end, and the blowing direction is parallel to the running direction of the tow; The blowing temperature of cooling zone A is 5-15°C higher than the ambient temperature, which is 40-50°C, and the blowing temperature of cooling zone B is 10-15°C lower than the ambient temperature; The inner diameter of the cooling zone A is larger than the inner diameter of the cooling zone B, and the inner diameter of the cooling zone A is smaller than the inner diameter of the cylindrical channel C.

2. A method for producing high modulus low shrinkage wire according to claim 1, characterized in that: The ambient temperature is 35-40℃.

3. A method for producing high modulus low shrinkage wire according to claim 2, characterized in that: A ring-blowing filter element is arranged inside the cooling zone A, and a sleeve I with a diameter larger than that of the ring-blowing filter element and coaxial with the ring-blowing filter element is arranged outside the cooling zone A. An annular cavity I is formed between the ring-blowing filter element and the sleeve I, and the annular cavity I is used for cooling air to enter.

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

5. A method for producing high modulus low shrinkage wire according to claim 4, characterized in that: A cylindrical tube is arranged inside the cooling zone B, and a sleeve II with a diameter larger than that of 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, and the annular cavity II is used for the cooling air to enter. 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 is 1 to 2 cm; the bottom of the sleeve I is fixedly connected to the top of the sleeve II.

6. A method for producing high modulus low shrinkage wire according to claim 5, characterized in that: The inner diameter of the ring-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 corridor C is 310-320 mm.

7. A method for producing high modulus low shrinkage wire according to claim 6, 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 corridor C is 690-710 mm.

8. A method for producing high modulus low shrinkage wire according to claim 7, characterized in that: The single yarn fineness of high modulus low shrinkage yarn is 4.71~5.65dtex, and the number of fiber roots is 200~240f.

9. A method for producing high modulus low shrinkage yarn according to claim 8, characterized in that: The spinning speed is 3000-3400 m / min, and the winding speed is 5800-6200 m / min.

10. A method for producing high modulus low shrinkage wire according to claim 9, characterized in that: The initial modulus of the high modulus low shrinkage yarn is 105-110 cN / dtex, and the dimensional stability is 7-8.5%.

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