Preparation method for high-modulus low-shrinkage polyester industrial yarn with high dimensional stability

Abstract

A preparation method for a high-modulus low-shrinkage polyester industrial yarn with high dimensional stability. The method comprises: extruding a polyester melt by means of a spinneret, and then sequentially subjecting same to slow cooling with a heat retarder (2), cooling in an air-free zone (3), cooling in an air blowing zone, finishing, drawing, setting, interlacing and winding so as to prepare a high-modulus low-shrinkage polyester industrial yarn with high dimensional stability, wherein the air blowing zone sequentially comprises a cold air zone (4), a hot air zone (5), an air exhaust section (6) and a duct (7) from top to bottom; and the environment temperature is 35-40°C, the cold air zone (4) has a temperature of 20-25°C, and the hot air zone (5) has a temperature of 120-130°C.

Description

A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn Technical Field

[0001] The invention belongs to the technical field of polyester industrial yarns and relates to a method for preparing polyester industrial yarns with high dimensional stability, high modulus and low shrinkage. Background Art

[0002] High-modulus, low-shrinkage polyester industrial yarn, with its excellent performance and low production cost, has become a mainstream product for rubber tire carcass materials. With the rapid development of new energy vehicles, the number of new energy vehicles in China has increased year by year. Due to their heavy weight and rapid acceleration, new energy vehicles require tires with higher wear and fatigue resistance. This requires high-modulus, low-shrinkage industrial yarn to possess high dimensional stability.

[0003] Patent KR100456340B1 states that in order to improve the dimensional stability of high-modulus, low-shrinkage polyester industrial yarn, it is necessary to increase the spinning speed and thus the spinning tension to increase the orientation of the nascent fibers and the formation of connecting chains between crystalline regions. However, the yarn bundle runs at a high speed and the yarn bundle stays in the cooling zone for a short time, making sufficient cooling difficult and prone to the formation of a skin-core structure. The formation of the skin-core structure causes the fiber cortex to bear the main spinning tension, which is not conducive to improving the orientation of the core layer, resulting in a low overall orientation of the fiber and a decrease in subsequent tensile strength. Even if the cooling air speed is increased to remove more heat from the fiber, it will cause the fiber to be disturbed and shake, resulting in uneven strands and even interference between different spindle strands. If the cooling zone length is extended to achieve sufficient cooling, it will be susceptible to external interference, the yarn bundle will shake greatly, the yarn will be easily broken, and the strand length will increase.

[0004] Prior art also employs a method of rapidly cooling the melt after extruding it through a spinneret (i.e., shortening the length of the slow cooling zone) and then cooling it with cooling air to improve the orientation of the spun fibers. However, due to the high linear density of industrial yarn monofilaments, this method results in uneven cooling of the inner and outer layers of the monofilaments, increasing the occurrence of a skin-core structure and reducing subsequent tensile strength. To ensure adequate cooling of the tow, a large plate with multiple holes is generally used (i.e., a large spinneret area increases the spacing between monofilaments, facilitating cooling air penetration; the fibers become thinner, making them easier to fully cool). Common specifications include 1000D / 336f and 1200D / 384f. This high number of holes means that the resulting high-modulus, low-shrinkage yarn monofilaments have low linear density, which increases production complexity and hinders subsequent stretching. Furthermore, in subsequent tire cord applications, the fiber-rubber contact surface area increases, increasing the chance of rubber decomposition (the molecules in the rubber can damage the ester bonds), resulting in poor tire fatigue resistance.

[0005] Generally speaking, in order to improve the fatigue resistance of the tire, it is necessary to increase the single-filament density and reduce the number of holes. This makes it difficult to fully cool the fiber, easily resulting in a skin-core structure, which is not conducive to improving the fiber strength and dimensional stability.

[0006] Therefore, it is of great practical significance to develop a production method for high-dimensional stability high-modulus low-shrinkage polyester industrial yarn to solve the problem that high-modulus low-shrinkage polyester industrial yarn in the existing technology cannot take into account fatigue resistance, fiber strength and dimensional stability.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing high-dimensional stability, high-modulus and low-shrinkage polyester industrial yarn.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn comprises the following steps: after polyester melt is extruded through a spinneret, it is sequentially subjected to slow cooling in a slow cooler, cooling in a windless zone, cooling in a blowing zone, oiling, stretching, shaping, web-forming, and winding to produce the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn; the blowing zone comprises, from top to bottom, a cold air zone, a hot air zone, an exhaust section, and a tunnel;

[0011] The ambient temperature is 35-40°C, the temperature of the cold air zone is 20-25°C, the temperature of the hot air zone is 120-130°C, and the spinning speed (i.e., the speed of one roller) is 3000-3400 m / min;

[0012] Among them, in the present invention, the filament bundle runs downward quickly, which will bring the air downward. Secondly, an exhaust section is provided below the hot air zone, and the exhaust section has the effect of sucking the air outward, so the air in the entire cooling area moves downward, and there is no convection (i.e., the hot air moves upward).

[0013] As the preferred technical solution:

[0014] In the above-mentioned method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the wind speed in the cold air zone is 0.4-0.7 m / s, and the wind speed in the hot air zone is 0.5-0.9 m / s.

[0015] A method for preparing a high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn as described above, wherein the dipped cord made of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn is subjected to a flexural fatigue test in accordance with the GB / T 33100-2016 standard, and the measured breaking strength retention rate is 80-90%; the dimensional stability index of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with the GB / T 16604-2017 standard (the dimensional stability index is the sum of the elongation of the fiber under a load of 4.0 cN / dtex and the dry heat shrinkage) is less than 7.8%.

[0016] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn as described in any of the above items, wherein the cold air zone has a ring-blowing structure, the air outlet is located on the inner side, and the air is blown from the outside to the inside, and the blowing direction is perpendicular to the running direction of the yarn tow;

[0017] The hot air zone has a ring-blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow.

[0018] As described above, a method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn is provided, wherein a ring-blowing filter element a is provided inside the cold air zone, and a sleeve a with a diameter greater than that of the ring-blowing filter element a and coaxial with the ring-blowing filter element a is provided outside the cold air zone, an annular cavity a is formed between the ring-blowing filter element a and the sleeve a, and the outside of the sleeve a is connected to the cold air duct.

[0019] As described above, a method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn is provided, wherein a ring-blowing filter element b is provided inside the hot air zone, and a sleeve b with a diameter larger than that of the ring-blowing filter element b and coaxial with the ring-blowing filter element b is provided outside the hot air zone, an annular cavity b is formed between the ring-blowing filter element b and the sleeve b, and the outside of the sleeve b is connected to the hot air duct.

[0020] In the method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn described above, the annular cavity a and the annular cavity b are not connected; the width of the annular cavity a is 1 to 2 cm, and the width of the annular cavity b is 1 to 2 cm.

[0021] As described above, in a method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the inner diameter of the ring-blown filter element a is 270-280 mm, and the inner diameter of the ring-blown filter element b is 250-260 mm; the exhaust section is equal to the inner diameter of the corridor, which is 300-310 mm, and the inner diameter of the ring-blown filter element in the cold air zone is slightly larger than that in the hot air zone, in order to increase the flow rate of the cooling air.

[0022] As described above, a method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn is provided. An exhaust port is provided on the side of the exhaust section, and a valve is provided at the exhaust port. The valve is used to adjust the airflow in the entire cooling zone to avoid turbulence. The exhaust port is connected to a suction fan. The corridor is a cylindrical structure, and is provided with evenly distributed circular holes. The circular holes run through the corridor. The circular holes are set to further cool the filament bundles passing through the hot air zone through the ambient temperature, and the ambient temperature is 35-40°C.

[0023] As described above, the method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn has a slow cooling zone height of 95-105 mm, a windless zone height of 45-55 mm, a cold air zone height of 450-470 mm, a hot air zone height of 400-420 mm, an exhaust section height of 350-380 mm, and a corridor height of 690-710 mm.

[0024] Principle of the present invention:

[0025] The present invention adopts a multi-stage cooling method to solve the problem in the prior art that the fatigue resistance, fiber strength and dimensional stability of industrial yarn cannot be achieved simultaneously.

[0026] The method of the present invention divides the cooling zone into multiple areas from top to bottom, including a cold air zone, a hot air zone, an exhaust section, and a corridor, and increases the spinning speed (single roller speed). By increasing the spinning speed and increasing the spinning tension, the orientation of the unstretched yarn and the formation of connecting chains between the crystallized regions are improved, thereby improving the dimensional stability of the high-modulus low-shrinkage yarn; however, increasing the spinning speed will result in a short cooling time. When the filaments are in the cold air zone, the heat on the surface is quickly taken away by the cooling air, the fiber cortex cools relatively quickly, the molecular orientation of the cortex is greater than that of the core layer, and the filament cortex reaches the solidification point when exiting the cold air zone, solidifies, and then enters the hot air zone.

[0027] The hot air zone heats the fiber whose cortex has been solidified. The main purposes are twofold: first, the hot air heats the fiber cortex, softening it (reaching a highly elastic state), increasing the cortex temperature and decreasing its viscosity, and reducing the viscosity difference between the fiber cortex and core layer; second, the softening of the fiber cortex (reaching a highly elastic state) promotes the movement of chain segments, increases the free volume between the cortex molecules, and facilitates the transfer of heat from the fiber core layer, thereby reducing the temperature difference between the fiber cortex and core layer. After passing through the hot air zone, the viscosity and temperature difference between the fiber cortex and core layer decreases. Under the action of spinning tension, the cortex and core layer are stretched synchronously, and the orientation and crystallization are more uniform. At this time, the orientation degree of the fiber cortex is slightly lower than that produced when only the cold air zone is used. However, since the viscosity and temperature difference between the fiber cortex and core layer decrease after passing through the hot air zone, the difference in the skin-core structure of the product is reduced, which is beneficial to improving the overall radial orientation of the fiber. In addition, a slight decrease in the orientation of the primary fiber cortex is conducive to the subsequent high-multiple uniform stretching by the hot roller. If the cortex orientation is too high, over-stretching is likely to occur during the subsequent high-multiple stretching, the molecular chain is broken, and the hair ends appear, which is not conducive to the improvement of strength.

[0028] Compared with fibers that have only undergone ordinary spinning processes (the conventional single-roll speed is 450-600 m / min, and the reason for setting it so low is to reduce the formation of skin-core structure), the fibers of the present invention have high dimensional stability. This is because the present invention increases the single-roll speed, thereby increasing the spinning tension, increasing the orientation of the unstretched yarn and the formation of connecting chains between crystal regions (refer to patents KR20150085683A and KR100456340B1), and has high dimensional stability.

[0029] The literature (Molecular Weight Discrete Distribution-Induced Orientation of High-Strength Copolyamide Fibers:Effects of Component Proportion and Molecular Weight.Macromolecules 2021 54(16),7529-7539) also points out that the formed connecting chain molecule (binding molecule) structure can inhibit the action of high tensile stress, induce and maintain the molecular chain orientation of the amorphous region, thereby making the fiber have a higher degree of orientation and mechanical properties. The present invention uses hot air above 120°C only to allow the cortex to reach a high elastic state above the glass transition temperature. The molecules continuously change their conformation through the internal rotation of the single bonds in the main chain, triggering the movement of the chain segments, and the entire molecular chain does not move (see Polymer Physics [M], He Manjun, 2007:106). Therefore, the connecting chain is still there at this time, only the chain segments shrink, the free volume between molecules increases, the gap between the cortex molecules becomes larger, and the heat of the core layer can be transferred out. After that, through stretching, the cortex and core layers are oriented synchronously, and the gap between the molecules becomes smaller, just like a net in a straightened state.

[0030] In addition, increasing the single-filament density is conducive to improving the stretching multiple, thereby increasing the strength of the fiber, and the fatigue resistance is also improved when the subsequent dipping is used in tires. Beneficial effects:

[0031] The method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn of the present invention is simple and easy to implement, and the prepared industrial yarn can achieve a balance between fatigue resistance, fiber strength and dimensional stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic diagram of a cooling device for high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn according to the present invention;

[0033] FIG2 is a schematic diagram of the airflow direction of a high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn according to the present invention.

[0034] Among them, 1-spinning box, 2-slow cooler, 3-windless area, 4-cold air area, 5-hot air area, 6-exhaust section, 7-corridor, 8-cold air inlet, 9-hot air inlet, 10-ring blowing filter element a, 11-ring blowing filter element b, 12-annular cavity a, 13-annular cavity b. DETAILED DESCRIPTION

[0035] 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.

[0036] Example 1

[0037] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the specific process is as follows:

[0038] As shown in Figure 1, the polyester melt is extruded through the spinneret on the spinning manifold 1 and then subjected to slow cooling in the slow cooling device 2, cooling in the windless zone 3, cooling in the blowing zone, oiling, stretching, shaping, networking and winding to produce high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn;

[0039] The height of the slow cooling zone where the slow cooler 2 is located is 102 mm, and the temperature of the slow cooling zone is 320°C; the height of the windless zone 3 is 52 mm;

[0040] The blowing area is divided into cold air area 4, hot air area 5, exhaust section 6 and corridor 7 from top to bottom;

[0041] As shown in Figure 2, the cold air zone 4 has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow; the cold air inlet 8 is located on the left side of the cold air zone 4; the height of the cold air zone 4 is 460mm; the wind speed of the cold air zone 4 is 0.6m / s, and the temperature is 23°C; the ambient temperature is 38°C;

[0042] A ring-blown filter element a10 with an inner diameter of 276 mm is provided inside the cold air zone 4. A sleeve a with a diameter greater than that of the ring-blown filter element a10 and coaxial with the ring-blown filter element a10 is provided outside the cold air zone 4. An annular cavity a12 with a width of 1.6 cm is formed between the ring-blown filter element a10 and the sleeve a. The outer side of the sleeve a is connected to the cold air duct.

[0043] The hot air zone 5 has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the filament bundle. The hot air inlet 9 is located on the left side of the hot air zone 5. The height of the hot air zone 5 is 405 mm. The wind speed of the hot air zone 5 is 0.7 m / s and the temperature is 125 ° C.

[0044] A ring-blowing filter element b11 with an inner diameter of 256 mm is provided inside the hot air zone 5. A sleeve b with a diameter larger than that of the ring-blowing filter element b11 and coaxial with the ring-blowing filter element b11 is provided outside the hot air zone 5. An annular cavity b13 with a width of 1.6 cm is formed between the ring-blowing filter element b11 and the sleeve b. The outer side of the sleeve b is connected to the hot air duct.

[0045] The annular cavity a 12 and the annular cavity b 13 are not connected;

[0046] An exhaust port is provided on the side of the exhaust section 6, and a valve is provided at the exhaust port, which is connected to the suction fan; the corridor 7 is a cylindrical structure, and is provided with evenly distributed circular holes, which penetrate the corridor 7; the inner diameter of the exhaust section 6 and the corridor 7 is equal, which is 306mm; the height of the exhaust section 6 is 365mm, and the height of the corridor 7 is 705mm;

[0047] The spinning speed is 3100 m / min, the stretching ratio is 2.2, the setting temperature is 250°C, the network pressure is 0.45 MPa, and the winding speed is 5700 m / min.

[0048] The dipped cord made of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn was subjected to a flexural fatigue test in accordance with GB / T 33100-2016 standard, and the measured breaking strength retention rate was 85%; the dimensional stability index of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with GB / T 16604-2017 standard was 7.7%.

[0049] Example 2

[0050] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the specific process is as follows:

[0051] After the polyester melt is extruded through the spinneret, it is sequentially subjected to slow cooling in the slow cooling device, cooling in the windless zone, cooling in the blowing zone, oiling, stretching, shaping, networking and winding to produce high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn;

[0052] The height of the slow cooling zone where the slow cooler is located is 95mm, and the temperature of the slow cooling zone is 290℃; the height of the windless zone is 45mm;

[0053] The blowing area is divided into cold air area, hot air area, exhaust section and corridor from top to bottom;

[0054] The cold air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the cold air zone is 465mm; the wind speed in the cold air zone is 0.4m / s, the temperature is 20℃, and the ambient temperature is 35℃.

[0055] A ring-blowing filter element a with an inner diameter of 270 mm is provided inside the cold air zone, and a sleeve a with a diameter larger than that of the ring-blowing filter element a and coaxial with the ring-blowing filter element a is provided outside the cold air zone. An annular cavity a with a width of 1 cm is formed between the ring-blowing filter element a and the sleeve a, and the outer side of the sleeve a is connected to the cold air duct;

[0056] The hot air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the hot air zone is 410mm; the wind speed in the hot air zone is 0.5m / s and the temperature is 120℃.

[0057] A ring-blowing filter element b with an inner diameter of 250 mm is provided inside the hot air zone, and a sleeve b with a diameter larger than that of the ring-blowing filter element b and coaxial with the ring-blowing filter element b is provided outside the hot air zone. An annular cavity b with a width of 1 cm is formed between the ring-blowing filter element b and the sleeve b, and the outer side of the sleeve b is connected to the hot air duct;

[0058] Annular cavity a and annular cavity b are not connected;

[0059] An exhaust port is provided on the side of the exhaust section, with a valve installed at the exhaust port, and is connected to the suction fan; the corridor is a cylindrical structure with evenly distributed circular holes running through the corridor; the exhaust section and the corridor have the same inner diameter of 300mm; the exhaust section height is 350mm, and the corridor height is 690mm;

[0060] The spinning speed is 3000 m / min, the stretching ratio is 1.9, the setting temperature is 245°C, the network pressure is 0.4 MPa, and the winding speed is 5600 m / min.

[0061] The dipped cord made of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn was subjected to a flexural fatigue test in accordance with GB / T 33100-2016 standard, and the measured breaking strength retention rate was 82%; the dimensional stability index of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with GB / T 16604-2017 standard was 7.5%.

[0062] Example 3

[0063] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the specific process is as follows:

[0064] After the polyester melt is extruded through the spinneret, it is sequentially subjected to slow cooling in the slow cooling device, cooling in the windless zone, cooling in the blowing zone, oiling, stretching, shaping, networking and winding to produce high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn;

[0065] The height of the slow cooling zone where the slow cooler is located is 104mm, and the temperature of the slow cooling zone is 330℃; the height of the windless zone is 54mm;

[0066] The blowing area is divided into cold air area, hot air area, exhaust section and corridor from top to bottom;

[0067] The cold air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the cold air zone is 450mm; the wind speed in the cold air zone is 0.65m / s, the temperature is 24℃; the ambient temperature is 39℃;

[0068] A ring-blowing filter element a with an inner diameter of 278 mm is provided inside the cold air zone, and a sleeve a with a diameter larger than that of the ring-blowing filter element a and coaxial with the ring-blowing filter element a is provided outside the cold air zone. An annular cavity a with a width of 1.8 cm is formed between the ring-blowing filter element a and the sleeve a, and the outer side of the sleeve a is connected to the cold air duct;

[0069] The hot air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the hot air zone is 400mm; the wind speed in the hot air zone is 0.8m / s and the temperature is 128℃.

[0070] A ring-blowing filter element b with an inner diameter of 258 mm is provided inside the hot air zone, and a sleeve b with a diameter larger than that of the ring-blowing filter element b and coaxial with the ring-blowing filter element b is provided outside the hot air zone. An annular cavity b with a width of 1.8 cm is formed between the ring-blowing filter element b and the sleeve b. The outer side of the sleeve b is connected to the hot air duct;

[0071] Annular cavity a and annular cavity b are not connected;

[0072] An exhaust port is provided on the side of the exhaust section, with a valve installed at the exhaust port, and is connected to the suction fan; the corridor is a cylindrical structure with evenly distributed circular holes running through the corridor; the exhaust section and the corridor have the same inner diameter of 308mm; the exhaust section height is 370mm, and the corridor height is 708mm;

[0073] The spinning speed is 3350 m / min, the stretching ratio is 2.3, the setting temperature is 248°C, the network pressure is 0.5 MPa, and the winding speed is 5900 m / min.

[0074] The dipped cord made of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn was subjected to a flexural fatigue test in accordance with GB / T 33100-2016 standard, and the measured breaking strength retention rate was 82.5%; the dimensional stability index of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with GB / T 16604-2017 standard was 7.1%.

[0075] Example 4

[0076] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the specific process is as follows:

[0077] After the polyester melt is extruded through the spinneret, it is sequentially subjected to slow cooling in the slow cooling device, cooling in the windless zone, cooling in the blowing zone, oiling, stretching, shaping, networking and winding to produce high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn;

[0078] The height of the slow cooling zone where the slow cooler is located is 98mm, and the temperature of the slow cooling zone is 300℃; the height of the windless zone is 45mm;

[0079] The blowing area is divided into cold air area, hot air area, exhaust section and corridor from top to bottom;

[0080] The cold air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the cold air zone is 455mm; the wind speed in the cold air zone is 0.5m / s, the temperature is 21℃, and the ambient temperature is 36℃.

[0081] A ring-blowing filter element a with an inner diameter of 272 mm is provided inside the cold air zone, and a sleeve a with a diameter larger than that of the ring-blowing filter element a and coaxial with the ring-blowing filter element a is provided outside the cold air zone. An annular cavity a with a width of 1.2 cm is formed between the ring-blowing filter element a and the sleeve a, and the outer side of the sleeve a is connected to the cold air duct;

[0082] The hot air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the hot air zone is 415mm; the wind speed in the hot air zone is 0.6m / s and the temperature is 123℃.

[0083] A ring-blowing filter element b with an inner diameter of 252 mm is provided inside the hot air zone, and a sleeve b with a diameter larger than that of the ring-blowing filter element b and coaxial with the ring-blowing filter element b is provided outside the hot air zone. An annular cavity b with a width of 1.2 cm is formed between the ring-blowing filter element b and the sleeve b. The outer side of the sleeve b is connected to the hot air duct;

[0084] Annular cavity a and annular cavity b are not connected;

[0085] An exhaust port is provided on the side of the exhaust section, with a valve installed at the exhaust port, and is connected to the suction fan; the corridor is a cylindrical structure with evenly distributed circular holes running through the corridor; the exhaust section and the corridor have the same inner diameter of 302mm; the height of the exhaust section is 355mm, and the height of the corridor is 695mm;

[0086] The spinning speed is 3100 m / min, the stretching ratio is 2, the setting temperature is 240°C, the network pressure is 0.4 MPa, and the winding speed is 5800 m / min.

[0087] The dipped cord made of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn was subjected to a flexural fatigue test in accordance with GB / T 33100-2016 standard, and the measured breaking strength retention rate was 84%; the dimensional stability index of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with GB / T 16604-2017 standard was 7.3%.

[0088] Example 5

[0089] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the specific process is as follows:

[0090] After the polyester melt is extruded through the spinneret, it is sequentially subjected to slow cooling in the slow cooling device, cooling in the windless zone, cooling in the blowing zone, oiling, stretching, shaping, networking and winding to produce high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn;

[0091] The height of the slow cooling zone where the slow cooler is located is 105mm, and the temperature of the slow cooling zone is 340℃; the height of the windless zone is 55mm;

[0092] The blowing area is divided into cold air area, hot air area, exhaust section and corridor from top to bottom;

[0093] The cold air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the cold air zone is 470mm; the wind speed in the cold air zone is 0.7m / s, the temperature is 25℃, and the ambient temperature is 40℃.

[0094] A ring-blowing filter element a with an inner diameter of 280 mm is provided inside the cold air zone, and a sleeve a with a diameter larger than that of the ring-blowing filter element a and coaxial with the ring-blowing filter element a is provided outside the cold air zone. An annular cavity a with a width of 2 cm is formed between the ring-blowing filter element a and the sleeve a, and the outer side of the sleeve a is connected to the cold air duct;

[0095] The hot air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the hot air zone is 405mm; the wind speed in the hot air zone is 0.9m / s and the temperature is 130℃.

[0096] A ring-blowing filter element b with an inner diameter of 260 mm is provided inside the hot air zone, and a sleeve b with a diameter larger than that of the ring-blowing filter element b and coaxial with the ring-blowing filter element b is provided outside the hot air zone. An annular cavity b with a width of 2 cm is formed between the ring-blowing filter element b and the sleeve b, and the outer side of the sleeve b is connected to the hot air duct;

[0097] Annular cavity a and annular cavity b are not connected;

[0098] An exhaust port is provided on the side of the exhaust section, with a valve installed at the exhaust port, and is connected to the suction fan; the corridor is a cylindrical structure with evenly distributed circular holes running through the corridor; the exhaust section and the corridor have the same inner diameter of 310mm; the exhaust section height is 380mm, and the corridor height is 710mm;

[0099] The spinning speed is 3400 m / min, the stretching ratio is 2.4, the setting temperature is 249°C, the network pressure is 0.5 MPa, and the winding speed is 6000 m / min.

[0100] The dipped cord made of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn was subjected to a flexural fatigue test in accordance with GB / T 33100-2016 standard, and the measured breaking strength retention rate was 88%; the dimensional stability index of the high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with GB / T 16604-2017 standard was 7.2%.

[0101] Example 6

[0102] A method for preparing high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn, the specific process is as follows:

[0103] After the polyester melt is extruded through the spinneret, it is sequentially subjected to slow cooling in the slow cooling device, cooling in the windless zone, cooling in the blowing zone, oiling, stretching, shaping, networking and winding to produce high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn;

[0104] The height of the slow cooling zone where the slow cooler is located is 100mm, and the temperature of the slow cooling zone is 310℃; the height of the windless zone is 50mm;

[0105] The blowing area is divided into cold air area, hot air area, exhaust section and corridor from top to bottom;

[0106] The cold air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the cold air zone is 465mm; the wind speed in the cold air zone is 0.55m / s, the temperature is 22℃; the ambient temperature is 37℃;

[0107] A ring-blowing filter element a with an inner diameter of 274 mm is provided inside the cold air zone, and a sleeve a with a diameter larger than that of the ring-blowing filter element a and coaxial with the ring-blowing filter element a is provided outside the cold air zone. An annular cavity a with a width of 1.4 cm is formed between the ring-blowing filter element a and the sleeve a, and the outer side of the sleeve a is connected to the cold air duct;

[0108] The hot air zone has a circular blowing structure, with the air outlet located on the inside, blowing from the outside to the inside, and the blowing direction is perpendicular to the direction of the tow. The height of the hot air zone is 420mm; the wind speed in the hot air zone is 0.65m / s and the temperature is 125℃.

[0109] A ring-blowing filter element b with an inner diameter of 254 mm is provided inside the hot air zone, and a sleeve b with a diameter larger than that of the ring-blowing filter element b and coaxial with the ring-blowing filter element b is provided outside the hot air zone. An annular cavity b with a width of 1.5 cm is formed between the ring-blowing filter element b and the sleeve b. The outer side of the sleeve b is connected to the hot air duct;

[0110] Annular cavity a and annular cavity b are not connected;

[0111] An exhaust port is provided on the side of the exhaust section, which is equipped with a valve and connected to the suction fan. The corridor is a cylindrical structure with evenly distributed circular holes running through it. The inner diameter of the exhaust section and the corridor is equal, at 304mm. The height of the exhaust section is 360mm, and the height of the corridor is 700mm.

[0112] The spinning speed is 3300 m / min, the stretching ratio is 2.1, the setting temperature is 248°C, the network pressure is 0.45 MPa, and the winding speed is 5500 m / min.

[0113] The dipped cord made of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn was subjected to a flexural fatigue test in accordance with GB / T 33100-2016 standard, and the measured breaking strength retention rate was 83%; the dimensional stability index of high-dimensional stability, high-modulus, low-shrinkage polyester industrial yarn measured in accordance with GB / T 16604-2017 standard was 7.4%.

Claims

1. A preparation method of high - dimensional - stability high - modulus low - shrinkage polyester industrial yarn. After the polyester melt is extruded through a spinneret, it is successively cooled by a slow - cooler, cooled in a non - wind area, cooled in a blowing area, oiled, drawn, shaped, texturized and wound to obtain the high - dimensional - stability high - modulus low - shrinkage polyester industrial yarn, which is characterized in that: The blowing area from top to bottom is successively the cold air area, the hot air area, the exhaust section and the channel; The ambient temperature is 35 - 40 °C, the temperature of the cold air area is 20 - 25 °C, and the temperature of the hot air area is 120 - 130 °C; The spinning speed is 3000 - 3400 m / min.

2. The preparation method of a high modulus and low shrinkage polyester industrial yarn with high dimensional stability according to claim 1, characterized in that, The wind speed of the cold air area is 0.4 - 0.7 m / s, and the wind speed of the hot air area is 0.5 - 0.9 m / s.

3. The preparation method of a high- dimensional stability, high- modulus and low- shrinkage polyester industrial yarn according to claim 2, characterized in that, For the dipped cord made of high - modulus low - shrinkage polyester industrial yarn with high dimensional stability, after the flex fatigue test according to the standard of GB / T 33100 - 2016, the breaking strength retention rate measured is 80 - 90%; The dimensional stability index of the high - modulus low - shrinkage polyester industrial yarn measured according to the standard of GB / T 16604 - 2017 is less than 7.8%.

4. A method for preparing a high - dimensional - stability, high - modulus and low - shrinkage polyester industrial yarn according to any one of claims 1 to 3, characterized in that, The cold air area is of a ring - blowing structure, the air outlet is located on the inner side, blowing from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow; The hot air area is of a ring - blowing structure, the air outlet is located on the inner side, blowing from the outside to the inside, and the blowing direction is perpendicular to the running direction of the tow.

5. The preparation method of a high modulus and low shrinkage polyester industrial yarn with high dimensional stability according to claim 4, characterized in that, Inside the cold air area, there is a ring - blowing filter element a. Outside the cold air area, there is a sleeve a with a diameter larger than that of the ring - blowing filter element a and coaxial with the ring - blowing filter element a. An annular cavity a is formed between the ring - blowing filter element a and the sleeve a, and the outside of the sleeve a is connected to the cold air pipeline.

6. The preparation method of a high-modulus and low-shrinkage polyester industrial yarn with high dimensional stability according to claim 5, characterized in that, Inside the hot air area, there is a ring - blowing filter element b. Outside the hot air area, there is a sleeve b with a diameter larger than that of the ring - blowing filter element b and coaxial with the ring - blowing filter element b. An annular cavity b is formed between the ring - blowing filter element b and the sleeve b, and the outside of the sleeve b is connected to the hot air pipeline.

7. The preparation method of a high-modulus and low-shrinkage polyester industrial yarn with high dimensional stability according to claim 6, characterized in that The annular cavity a and the annular cavity b are not connected; the width of the annular cavity a is 1 - 2 cm, and the width of the annular cavity b is 1 - 2 cm.

8. The preparation method of a high-modulus and low-shrinkage polyester industrial yarn with high dimensional stability according to claim 6, characterized in that, The inner diameter of the ring - blowing filter element a is 270 - 280 mm, the inner diameter of the ring - blowing filter element b is 250 - 260 mm; the inner diameters of the exhaust section and the channel are equal, being 300 - 310 mm.

9. The preparation method of a high-modulus and low-shrinkage polyester industrial yarn with high dimensional stability according to claim 8, characterized in that On the side of the exhaust section, there is an exhaust port, a valve is provided at the exhaust port, and the exhaust port is connected to a suction fan; the channel is of a cylindrical structure, and there are evenly distributed round holes on the channel, and the round holes penetrate through the channel.

10. The preparation method of a high- dimensional stability, high- modulus and low- shrinkage polyester industrial yarn according to claim 1, characterized in that, The height of the cold air area is 450 - 470 mm, the height of the hot air area is 400 - 420 mm, the height of the exhaust section is 350 - 380 mm, and the height of the channel is 690 - 710 mm.

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