Preparation device and preparation method of polyester industrial yarn for air bag restraint system

Abstract

The invention belongs to the technical field of spinning, and relates to a preparation device and a preparation method of polyester industrial yarn for an air bag restraint system. The preparation device comprises a spinneret plate, a cooling air duct, four wire moving barrels, a cross-shaped annular non-porous plate, a cross-shaped annular porous plate, a suction barrel, an annular non-porous plate, an annular porous plate, an air supply pipeline and a suction pipeline. An air supply cavity is defined by the four wire feeding cylinders, the upper section of the cooling air cylinder, the cross-shaped circular-ring-shaped non-porous plate and the cross-shaped circular-ring-shaped porous plate; a plurality of grooves are formed in the inner wall of the middle section of the cooling air cylinder, and the suction cylinder, the annular non-porous plate, the annular porous plate and the lower section of the cooling air cylinder jointly define a suction cavity; and the suction pipeline is horizontally arranged and is communicated with the suction cavity. The preparation device is adopted in the preparation method. The polyester industrial yarn prepared by the preparation method disclosed by the invention is flat, high in breaking strength, high in elongation at break and high in yarn evenness, the softness of air bag fabric is improved, and the polyester industrial yarn has important application value in the field of automobile safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of spinning, and relates to a preparation device and a preparation method for polyester industrial yarns for airbags. Background Art

[0002] In recent years, with the enhancement of people's safety awareness, airbags, as one of the important components of automotive passive safety systems, have been widely known. When a vehicle collision occurs, airbags cooperate with seat belts to effectively reduce the impact on parts such as the heads and chests of passengers, achieving the purpose of protecting passenger safety. With the increasing number of automotive airbag installations, there are higher and higher requirements for the lightweighting of automotive airbags.

[0003] Current automotive airbags are composed of airbag fabrics. In order to achieve pressure retention and low air permeability, the airbag fabrics generally need to be coated with glue, which makes automotive airbags heavy and increases costs. According to the invention patent application with the publication number CN105256597A, after calendering finishing, the chemical fiber filaments in the airbag fabric will present a flat structure. This flat structure has a special "one"-shaped cross-section, and the airtightness is not affected, while the glue coating amount is reduced by 38%. Therefore, developing flat airbag filaments can, on the one hand, ensure that the airbag fabric has good airtightness, on the other hand, reduce the glue coating amount, save costs, and make automotive airbags more lightweight.

[0004] Polyester industrial yarns have the characteristic of high strength and have important application value in the field of automotive airbags. When the fiber cross-section of polyester industrial yarns changes from circular to "one"-shaped, the rigidity of the fibers is weakened, and at the same time, the elongation at break of the fibers is increased, which can increase the softness of the fibers. However, polyester industrial yarns are generally 96F or 144F, with a large number of single filaments in each filament bundle. The "one"-shaped cross-section is asymmetrical, making it difficult to cool the filament bundle evenly.

[0005] In order to solve the problem of uneven cooling of the filament bundle composed of flat filaments, there has been little research in the prior art.

[0006] For example, the invention patent application with the publication number CN104831382A discloses a production method of bright flat polyester filament. Side blowing cooling is adopted, and the direction of the side blowing wind is parallel to the extension direction of the spinneret blade. However, during the spinning process, due to the large number of monofilaments and the small spinning tension of the nascent fiber, after the fiber exits the spinneret hole, affected by the airflow between the fibers and the external environment (such as the opening and closing of the side blowing spinning window and the movement of on-site staff), it is very difficult to ensure that the fiber blade direction is always parallel to the cooling wind direction during the cooling process. In this way, there will be a situation where the blowing wind direction is perpendicular to the fiber blade direction. The flat monofilament has a large aspect ratio, and the heat carried away by the blowing wind direction parallel to the fiber blade direction is greater than that of the blowing wind direction perpendicular to the fiber blade direction, resulting in uneven cooling between the flat monofilaments. The breaking elongation rate of the produced fiber decreases, unable to meet the softness requirements of the airbag fabric. Moreover, uneven stretching is likely to occur during the subsequent stretching, the fiber evenness deteriorates, and the number of hairiness breakages increases.

[0007] Another example is that the invention patent application with the publication number CN106400167A discloses a porous superfine flat filament and its preparation method. The arrangement of the spinneret holes on the spinneret is designed from circular arrangement to elliptical arrangement. When the effective area of the spinneret is the same, the number of layers of the elliptical arrangement of the spinneret holes is less than that of the circular arrangement, and the number of holes of the elliptical arrangement of the spinneret holes is greater than that of the circular arrangement. The spinning fine stream is cooled by passing through the ring blowing wind. However, the direction of this ring blowing wind cannot always be parallel to the fiber blade direction, and uniform cooling cannot be achieved. The breaking elongation rate of the produced fiber decreases, unable to meet the softness requirements of the airbag fabric. At the same time, uneven stretching is likely to occur during stretching, and the evenness deteriorates.

[0008] Therefore, it is necessary to develop a preparation device and manufacturing method for polyester industrial yarn for airbags that can take into account flatness, high breaking strength, high breaking elongation rate, and high evenness. Summary of the Invention

[0009] The purpose of the present invention is to solve the above problems existing in the prior art and provide a preparation device and preparation method for polyester industrial yarn for airbags.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] A preparation device for polyester industrial yarn for airbags includes a spinneret, a cooling air cylinder, 4 wire guiding cylinders, a cross-circular non-porous plate, a cross-circular porous plate, a suction cylinder, a circular non-porous plate, a circular porous plate, a air supply pipeline, and a suction pipeline;

[0012] Both ends of the cooling air cylinder are open, the cylinder wall is non-porous, it is vertically arranged, is cylindrical, and is divided into upper, middle, and lower sections;

[0013] Both ends of the four wire guiding cylinders are open, the cylinder walls are without holes, and they are vertically arranged in the upper section of the cooling air cylinder. The upper ends of the four wire guiding cylinders are flush with the upper end of the upper section of the cooling air cylinder, and the five are connected by a cross-shaped circular ring without holes. The lower ends of the four wire guiding cylinders are flush with the lower end of the upper section of the cooling air cylinder, and the five are connected by a cross-shaped circular ring with holes. The cross-shaped circular ring is composed of a circular ring and a cross shape located therein. The four wire guiding cylinders, the upper section of the cooling air cylinder, the cross-shaped circular ring without holes, and the cross-shaped circular ring with holes jointly enclose an air supply cavity;

[0014] A plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder are provided on the inner wall of the middle section of the cooling air cylinder. The boundary layer is a fluid layer formed due to viscous action when the cooling air flows through the inner wall surface of the cooling air cylinder;

[0015] Both ends of the suction cylinder are open, the cylinder wall is without holes, and it is vertically arranged in the lower section of the cooling air cylinder and coaxial with it. The upper end of the suction cylinder is flush with the upper end of the lower section of the cooling air cylinder, and the two are connected by an annular perforated plate. The lower end of the suction cylinder is flush with the lower end of the lower section of the cooling air cylinder, and the two are connected by an annular non-perforated plate. The suction cylinder, the annular non-perforated plate, the annular perforated plate, and the lower section of the cooling air cylinder jointly enclose a suction cavity;

[0016] The air supply duct is horizontally arranged and communicated with the air supply cavity; the suction duct is horizontally arranged and communicated with the suction cavity;

[0017] The spinneret holes on the spinneret plate are distributed in four areas, and the four areas are respectively located directly above the hollow parts of the four wire guiding cylinders.

[0018] The principle of the present invention is as follows:

[0019] Due to the non-circularly symmetric characteristic of the flat filament cross-section, if the cooling method of ring blowing or side blowing vertical blowing in the prior art is adopted, the ideal state is that the blowing direction is parallel to the fiber blade direction (such as the design of the patent application with the patent publication number CN104831382A), which can take away the heat of the filament bundle to the greatest extent and achieve the cooling effect. Without considering the environmental impact, it is necessary to increase the spinning tension, and the following problems will occur: 1. When the spinning tension increases, the orientation and crystallization degree of the nascent fiber are large, and the remaining elongation at break is low, which is not conducive to the improvement of the fiber elongation at break and affects the softness of the airbag fabric; 2. When the spinning tension is large, the surface tension of the melt filament increases, which will cause the flat filament cross-section to tend to become circular and the profile degree decreases; 3. When the tension is too large, there will be broken ends and fuzz, and stable production cannot be achieved. The prior art mainly adopts the method of shortening the length of the windless area to cool it quickly and maintain the profile degree, and then extending the cooling length to achieve the purpose of sufficient cooling; compared with the circular cross-section fiber, the flat filament has a larger specific surface area. When the cooling zone length is extended, the frictional resistance between the filament bundle and the air increases, and the spinning tension increases, which is not conducive to the improvement of the fiber elongation at break;

[0020] The present invention sets the structure of the cooling air duct, the position of the air supply duct, the connection mode between the air supply duct and the cooling air duct, etc., so that the flow direction of the cooling air in the cooling air duct is the same as the running direction of the tow. Through the "field" - shaped cavity structure of the thread - guiding cylinder, the tow is divided into four regions for synchronous cooling. The advantages are as follows: 1. The cross - section of the flat filament has the characteristic of non - circular symmetry. The heat carried away by the cooling air flowing perpendicular to the flat - filament blade direction and parallel to the blade direction is different, resulting in different cooling uniformity of the single filaments. By using the cooling air with the same running direction as the tow, this problem does not exist, solving the problem of cooling uniformity of the flat filament; 2. Dividing the tow into four regions for synchronous cooling reduces the problem of uneven cooling of the inner and outer circles of the spinneret for multi - hole polyester filament; 3. The flat filament has the characteristic of a large specific surface area. Compared with the traditional vertical blowing methods of ring blowing and side blowing, using the cooling air parallel to the running direction of the tow can reduce the velocity difference between the air and the tow, effectively reducing the air friction, and further reducing the spinning tension. At the stage where the spinning melt is extruded to form the nascent fiber, the spinning tension plays a role in increasing the molecular orientation of the polymer and inducing stress crystallization. Reducing the spinning tension can reduce the degree of molecular orientation and the crystallinity of the nascent fiber. The nascent fiber has a relatively high residual elongation rate. After subsequent stretching by the hot roller, at the same stretching ratio, the fiber not only maintains a certain strength but also maintains a high elongation rate, meeting the requirements of the softness of the airbag fabric;

[0021] However, such a setting is likely to cause excessive turbulence and flow separation in the cooling air duct, having an adverse effect on the evenness of the tow. To avoid excessive turbulence and flow separation, the present invention also makes the following improvements:

[0022] ① Set grooves on the inner wall of the cooling air duct;

[0023] In the prior art, the inner - wall surface of the cooling air duct is a smooth plane. When the cooling air flows through the cooling air duct, the viscous action of the air flow generates friction with the inner - wall surface of the cooling air duct. The cooling air in contact with the inner - wall surface of the cooling air duct slows down, forming a very thin boundary layer. The flow velocity outside the boundary layer changes little, while the flow velocity inside changes violently. In the cross - section direction of the cooling air duct, the flow velocities on both sides near the inner - wall surface of the cooling air duct are smaller, and the flow velocity in the middle part is the same as the incoming flow velocity, with little change; due to the large velocity gradient inside the boundary layer, the kinetic energy of the flow is lost due to the action of the viscous force, and the inner - layer flow velocity will become slower and slower. According to Bernoulli's theorem, when the flow velocity slows down, the pressure increases; as the flow progresses, the flow inside the boundary layer becomes more and more difficult, and finally separates from the inner - wall surface of the cooling air duct, generating a huge separation vortex; the generation of the vortex makes the cooling air become chaotic, which will disturb the tow and affect the cooling of the tow;

[0024] The present invention provides a groove on the inner wall of the cooling air duct. The cooling air can generate small refraction flows at the groove, avoiding the generation of large separation vortices, thereby suppressing the separation of the boundary layer and avoiding large separation vortices. It is like applying an "oil film" on the wall of the cooling air duct, reducing the flow resistance of the air flow outside the "oil film", making the overall flow velocity on the cross-section of the cooling air duct more stable and uniform, enabling more uniform cooling of the tow, and improving the evenness of the tow;

[0025] ② A suction pipeline is arranged at the end position of the tow cooling;

[0026] At the outlet position of the cylindrical cooling air duct, the cooling air, due to the sudden increase in the air flow channel (the cooling air is no longer restricted by the cooling air duct), has a reduced flow velocity and an increased pressure, resulting in a reverse flow at the outlet of the cooling air duct, disturbing the tow. Although the tow has been cooled and solidified at this time, the disturbance of the tow will be conducted upward, which is not conducive to improving the evenness of the tow. The present invention arranges a suction pipeline at the end position of the tow cooling and adjusts the suction force of the suction pipeline to keep the cooling air in a stable flow state, reducing the disturbance of the tow, thereby improving the evenness of the tow.

[0027] As a preferred technical solution:

[0028] For the preparation device of the polyester industrial yarn for airbag as described above, the circular ring inside is equally divided into four parts in a cross shape; the cross-sections at various positions of the 4 wire guiding cylinders are all fan-shaped and have the same size; the spinneret holes on the spinneret plate are rectangular, and the aspect ratio of the length to the width is 7.1 - 10:1.

[0029] For the preparation device of the polyester industrial yarn for airbag as described above, the groove is a round pit groove, arranged in a staggered dot matrix structure; the diameter of the round pit groove is 3 - 4 mm, the groove depth is 2 - 2.5 mm, and the center distance between any two adjacent round pits is 9 - 10 mm.

[0030] For the preparation device of the polyester industrial yarn for airbag as described above, the groove is a non-round pit groove, divided into multiple groups. The non-round pit grooves in the same group are distributed along the circumferential pitch in the middle section of the cooling air duct with a pitch of 4 - 6 mm, and the non-round pit grooves in different groups are distributed along the axial pitch in the middle section of the cooling air duct with a pitch of 9 - 10 mm;

[0031] The non-round pit groove gradually tapers in size from the groove opening to the groove bottom. The groove opening is an oblong shape, with a length of 9 - 20 mm and a width of 3 - 4 mm for the oblong shape. The groove bottom is a line segment shape or a rectangular shape, and the groove depth is 2 - 2.5 mm;

[0032] When the groove bottom is rectangular, the angle θ between the groove wall and the central axis of the non-round pit groove is 20 - 30°;

[0033] For the same non-circular pit groove, the short axis of the oblong shape, the perpendicular bisector of the line segment shape, and the short axis of the rectangular shape are all parallel to the axial direction of the cooling air cylinder, and the straight line where the center of the oblong shape and the midpoint of the line segment shape or the center of the rectangular shape are located is perpendicular to and intersects the central axis of the cooling air cylinder.

[0034] For the preparation device of polyester industrial yarn for airbag as described above, the inner diameter of the cooling air cylinder is 100 - 200 mm, the length of the upper section is 110 - 150 mm, the length of the middle section is 1000 - 1200 mm, and the length of the lower section is 110 - 150 mm.

[0035] For the preparation device of polyester industrial yarn for airbag as described above, the outer diameter of the wire guiding cylinder is 40 - 60 mm smaller than the inner diameter of the cooling air cylinder.

[0036] For the preparation device of polyester industrial yarn for airbag as described above, the outer diameter of the suction cylinder is 40 - 60 mm smaller than the inner diameter of the cooling air cylinder.

[0037] For the preparation device of polyester industrial yarn for airbag as described above, the inner diameter of the air supply pipeline is 100 - 120 mm, and the inner diameter of the suction pipeline is 100 - 120 mm.

[0038] For the preparation device of polyester industrial yarn for airbag as described above, it further includes a spinning box body, and the spinning box body is located above the cooling air cylinder, and between the two are a slow cooling area and a windless area, and the slow cooling area is located above the windless area.

[0039] For the preparation device of polyester industrial yarn for airbag as described above, the height of the slow cooling area is 95 - 105 mm; the height of the windless area is 45 - 55 mm.

[0040] For the preparation device of polyester industrial yarn for airbag as described above, it further includes a spinning channel, and the spinning channel is located below the cooling air cylinder and is connected to it.

[0041] For the preparation device of polyester industrial yarn for airbag as described above, the length of the spinning channel is 600 - 700 mm.

[0042] The present invention also provides a preparation method of polyester industrial yarn for airbag, adopting the preparation device of polyester industrial yarn for airbag as described in any one of the above.

[0043] As a preferred technical solution:

[0044] For the preparation method of polyester industrial yarn for airbag as described above, the spinning process flow is: polyester melt is extruded through a spinneret plate → cooled in the slow cooling area → cooled in the windless area → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → networked → wound;

[0045] The spinning process parameters include: ambient temperature 35 - 40 °C; spinning temperature 291 - 310 °C; temperature in the slow cooling zone 290 - 320 °C; cooling air temperature 30 - 35 °C; cooling air velocity 0.5 - 1.0 m / s; suction force of the suction pipeline ≤ 0.2 Pa; speed of the first pair of hot rollers 430 - 560 m / min, temperature 60 - 70 °C; speed of the second pair of hot rollers 450 - 580 m / min, temperature 90 - 100 °C; speed of the third pair of hot rollers 1850 - 2260 m / min, temperature 123 - 135 °C; speed of the fourth pair of hot rollers 2650 - 3600 m / min, temperature 210 - 250 °C; speed of the fifth pair of hot rollers 2580 - 3620 m / min, temperature 210 - 250 °C; speed of the sixth pair of hot rollers 2380 - 3420 m / min, temperature 180 - 220 °C; total draw ratio 5.52 - 6.38, primary draw ratio 3.70 - 4.22, secondary draw ratio 1.39 - 1.71, total draw ratio = speed of the fourth pair of hot rollers / speed of the second pair of hot rollers, primary draw ratio = speed of the third pair of hot rollers / speed of the second pair of hot rollers, secondary draw ratio = speed of the fourth pair of hot rollers / speed of the third pair of hot rollers; winding speed 2550 - 3610 m / min; spinning tension 60 - 80 cN;

[0046] The linear density of the polyester industrial yarn for airbags is 420 - 600 dtex, the number of holes is 96 - 144 F, the breaking strength ≥ 7.6 cN / dtex, the breaking elongation is 30 ± 2%, the CV value of the evenness variation ≤ 1%, the dry heat shrinkage rate ≤ 4.15%, the downgrading rate of hairiness ≤ 1.12%, and the fiber flatness is 3.1 - 4.2.

[0047] Beneficial effects:

[0048] (1) The preparation device of the present invention makes the flow direction of the cooling air in the cooling air cylinder the same as the running direction of the tow, and divides the tow into four regions through the wire guiding cylinder for synchronous cooling, solving the problem of uneven cooling of flat fibers. The prepared flat fibers not only maintain a high breaking strength but also maintain a high breaking elongation, improving the softness of the airbag fabric and meeting the requirements for the softness of the airbag fabric;

[0049] (2) The preparation device of the present invention is provided with grooves on the inner wall surface of the cooling air cylinder to reduce the adhesion force of the cooling air to the wall surface, and a suction pipeline is arranged at the end position where the tow cooling ends, so that the cooling air is always in a stable state. Finally, through the grooves and the suction pipeline, the disturbance of the tow is avoided, and the evenness of the tow is improved.

[0050] (3) The preparation method of the present invention reduces the amount of glue applied, saves costs, and meets the requirements for the lightweight of the airbag fabric. Description of the Drawings

[0051] Figure 1 is a schematic structural view of the preparation device of the present invention;

[0052] Figure 2 is a bottom view schematic of the wire take-up cylinder of the preparation device of the present invention;

[0053] Figure 3 is a front view schematic of the wire take-up cylinder of the preparation device of the present invention;

[0054] Figure 4 is a partial schematic of the airflow at the inner wall surface of the cooling air cylinder of the preparation device of the present invention (circular pit groove);

[0055] Figure 5 is a partial schematic of the airflow at the inner wall surface of the cooling air cylinder of the preparation device of the present invention (non-circular pit groove);

[0056] Figure 6 is a combined front and top view schematic of the non-circular pit groove (V-shaped groove) on the inner wall of the cooling air cylinder of the preparation device of the present invention;

[0057] Figure 7 is a combined front and top view schematic of the non-circular pit groove (inverted isosceles trapezoidal groove) on the inner wall of the cooling air cylinder of the preparation device of the present invention;

[0058] Figure 8 is a partial schematic of the airflow at the outlet of the cooling air cylinder of Comparative Example 1A;

[0059] Figure 9 is a partial schematic of the airflow at the inner wall surface of the cooling air cylinder of Comparative Example 2A;

[0060] Figure 10 is a schematic structural view of the cooling air cylinder of Comparative Example 3A;

[0061] In the figure, 1 is a spinning box body, 2 is a slow cooling zone, 3 is a windless zone, 4 is a wire take-up cylinder, 5 is cooling air, 6 is a air supply duct, 7 is a suction duct, 8 is a suction cylinder, 9 is a fiber bundle, 10 is a cooling air cylinder, 11 is a spinning channel, 12 is a reverse airflow, 13 is a circular pit groove, 14 is a refracted flow of the circular pit groove, 15 is a non-circular pit groove, and 16 is a refracted flow of the non-circular pit groove. Detailed Embodiments

[0062] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0063] The following are the test methods for relevant performance indicators in each example and comparative example:

[0064] (1)Linear density: Tested using a YG086 type length measuring instrument with reference to GB / T 14343-2008 "Test Method for Linear Density of Filament Yarns of Chemical Fibers".

[0065] (2)Number of holes: In the production of chemical fibers, the "number of holes" usually refers to the number of spinneret holes on the spinneret plate, that is, how many filaments a fiber is composed of. The number of holes is detected using a SpinTrak spinneret detector from Aspex Corporation in the United States.

[0066] (3)Breaking strength: Tested using a YG023B-Ⅱ type full-automatic single yarn strength tester with reference to GB / T 14344-2022 "Test Method for Tensile Properties of Filament Yarns of Chemical Fibers".

[0067] (4)Elongation at break: Tested using a YG023B-Ⅱ type full-automatic single yarn strength tester with reference to GB / T 14344-2022 "Test Method for Tensile Properties of Filament Yarns of Chemical Fibers".

[0068] (5)CV value of evenness variation: Tested using a USTER TESTER 5 type evenness tester with reference to GB / T 14346-2015 "Test Method for Evenness Variation of Filament Yarns of Chemical Fibers - Capacitance Method".

[0069] (6)Dry heat shrinkage rate: Tested using a TST510 / 250 type dry heat shrinkage rate tester with reference to GB / T 16604-2017 "Polyester Industrial Filament Yarns".

[0070] (7)Rate of downgrading due to hairiness: Referring to the specific inspection method for the appearance requirements in GB / T 16604-2017 "Polyester Industrial Filament Yarns", count the number of caked yarns downgraded due to hairiness and the number of full-wound caked yarns in one day. The percentage of the number of caked yarns downgraded due to hairiness in the number of full-wound caked yarns is the rate of downgrading due to hairiness.

[0071] (8)Fiber flatness (flatness of single filament): According to FZ / T 50002-2013 "Test Method for Shape Irregularity of Chemical Fibers", first obtain the cross-sectional diagram of the fiber through a microscope, then measure the length value and width value of the fiber, and finally calculate the fiber flatness by dividing the length value by the width value.

[0072] Example 1A

[0073] As Figures 1 - 3A preparation device for polyester industrial yarn for airbags as shown, which is composed of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, 4 wire guiding cylinders 4, a cross-shaped circular ring non-porous plate, a cross-shaped circular ring porous plate, a suction cylinder 8, a circular ring non-porous plate, a circular ring porous plate, a air supply pipeline 6, a suction pipeline 7 and a spinning channel 11;

[0074] Both ends of the cooling air cylinder 10 are open, the cylinder wall is non-porous, it is vertically arranged, is cylindrical, and is divided into upper, middle and lower sections;

[0075] Both ends of the 4 wire guiding cylinders 4 are open, the cylinder wall is non-porous, and they are vertically arranged inside the upper section of the cooling air cylinder 10. The upper ends of the 4 wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring non-porous plate. The lower ends of the 4 wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring porous plate. The cross-shaped circular ring is composed of a circular ring and a cross shape located therein. The cross shape equally divides the inside of the circular ring into four parts. The 4 wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-shaped circular ring non-porous plate and the cross-shaped circular ring porous plate jointly enclose an air supply cavity; The cross sections of the 4 wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0076] As Figure 4 As shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air cylinder 10. The grooves are round pit grooves 13, which are arranged in a staggered dot matrix structure. The cooling air 5 generates small round pit groove refraction flows 14 at the round pit grooves 13. The diameter of the round pit grooves 13 is 3.5 mm, the groove depth is 2.2 mm, and the center distance between any two adjacent round pits is 9 mm;

[0077] Both ends of the suction cylinder 8 are open, the cylinder wall is non-porous, it is vertically arranged inside the lower section of the cooling air cylinder 10 and is coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10 and the two are connected through a circular ring porous plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10 and the two are connected through a circular ring non-porous plate. The suction cylinder 8, the circular ring non-porous plate, the circular ring porous plate and the lower section of the cooling air cylinder 10 jointly enclose a suction cavity; The inner diameter of the cooling air cylinder 10 is 200 mm, the length of the upper section is 120 mm, the length of the middle section is 1200 mm, and the length of the lower section is 150 mm; The outer diameter of the wire guiding cylinder 4 is 40 mm smaller than the inner diameter of the cooling air cylinder 10; The outer diameter of the suction cylinder 8 is 40 mm smaller than the inner diameter of the cooling air cylinder 10;

[0078] The air supply pipeline 6 is horizontally arranged and communicated with the air supply cavity; The suction pipeline 7 is horizontally arranged and communicated with the suction cavity; The inner diameter of the air supply pipeline 6 is 110 mm, and the inner diameter of the suction pipeline 7 is 110 mm;

[0079] The spinneret holes on the spinneret plate are rectangular, with a length-to-width ratio of 8:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively directly above the hollow parts of the 4 wire guiding cylinders 4;

[0080] The spinning box 1 is located above the cooling air cylinder 10, and between them are the slow cooling zone 2 and the windless zone 3. The slow cooling zone 2 is located above the windless zone 3. The filament bundle 9 coming out of the spinning box 1 enters the wire guiding cylinder 4 after passing through the slow cooling zone 2 and the windless zone 3, and then the filament bundle 9 enters the cooling air cylinder 10. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling zone 2 is 100 mm; the height of the windless zone 3 is 55 mm;

[0081] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it; the length of the spinning duct 11 is 600 mm.

[0082] Example 1B

[0083] A method for preparing polyester industrial yarn for airbags, using the preparation device for polyester industrial yarn for airbags in Example 1A above. The spinning process flow is: the polyester melt is extruded through the spinneret plate → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rolls → shaped → texturized → wound;

[0084] The spinning process parameters are: ambient temperature 35 °C; spinning temperature 290 °C; slow cooling zone temperature 310 °C; cooling air temperature 32 °C; cooling air speed 0.7 m / s; suction force of the suction pipeline 0.1 Pa; speed of the first pair of hot rolls 480 m / min, temperature 60 °C; speed of the second pair of hot rolls 495 m / min, temperature 95 °C; speed of the third pair of hot rolls 1980 m / min, temperature 130 °C; speed of the fourth pair of hot rolls 2885 m / min, temperature 242 °C; speed of the fifth pair of hot rolls 2740 m / min, temperature 240 °C; speed of the sixth pair of hot rolls 2550 m / min, temperature 200 °C; total draw ratio 5.83, main draw ratio 4, secondary draw ratio 1.46; winding speed 2600 m / min; spinning tension 60 cN.

[0085] The polyester industrial yarn for airbags prepared has a linear density of 450 dtex, 96 holes, a breaking strength of 7.8 cN / dtex, a breaking elongation rate of 28%, a CV value of the evenness variation rate of 0.5%, a dry heat shrinkage rate of 4%, a downgrading rate of hairiness of 0.9%, and a fiber flatness of 3.1.

[0086] Comparative Example 1A

[0087] A preparation device for polyester industrial yarn is basically the same as that in Example 1A, and the only difference is that: the suction pipeline is not provided. As Figure 8As shown, both the cooling air 5 and the tow 9 are located inside the cooling air cylinder 10, and the cooling air 5 forms a reverse air flow 12 at the outlet of the cooling air cylinder 10.

[0088] Comparative Example 1B

[0089] A method for preparing polyester industrial yarn is basically the same as that of Example 1B, and the only difference is that: the preparation device of a polyester industrial yarn provided by Comparative Example 1A is adopted.

[0090] The linear density of the obtained polyester industrial yarn is 450 dtex, the number of holes is 96F, the breaking strength is 7.8 cN / dtex, the breaking elongation is 28%, the CV value of the evenness variation is 1.4%, the dry heat shrinkage rate is 4%, the downgrading rate of hairiness is 1.9%, and the fiber flatness is 3.1.

[0091] Comparing Comparative Example 1B with Example 1B, the changes in the linear density, breaking strength, breaking elongation, and dry heat shrinkage rate of the polyester industrial yarn prepared in Comparative Example 1B are not obvious. The CV value of the evenness variation increases by 0.9%, and the downgrading rate of hairiness increases by 1.0%. This is because a suction pipeline is not set at the outlet position of the cooling air cylinder, the cooling air forms a reverse air flow at the outlet of the cooling air cylinder, the air pressure at the outlet of the cooling air cylinder fluctuates, the tow is disturbed here, the single filaments "fight" with each other, and it is conducted to the upper tow cooling area, resulting in an increase in the CV value of the evenness variation of the tow and an increase in hairiness, indicating that the suction pipeline has an important influence on the evenness and hairiness.

[0092] Comparative Example 2A

[0093] A preparation device for polyester industrial yarn is basically the same as that of Example 1A, and the only difference is that: neither the round pit groove nor the non-round pit groove is set. As Figure 9 shown, the cooling air 5 forms a reverse air flow 12 inside the cooling air cylinder 10.

[0094] Comparative Example 2B

[0095] A method for preparing polyester industrial yarn is basically the same as that of Example 1B, and the only difference is that: the preparation device of a polyester industrial yarn provided by Comparative Example 2A is adopted.

[0096] The linear density of the obtained polyester industrial yarn is 450 dtex, the number of holes is 144F, the breaking strength is 7.5 cN / dtex, the breaking elongation is 29%, the CV value of the evenness variation is 1.8%, the dry heat shrinkage rate is 4.12%, the downgrading rate of hairiness is 1.3%, and the fiber flatness is 3.5.

[0097] Comparative Example 2B and Example 1B were compared. For the polyester industrial yarn produced in Comparative Example 2B, the changes in linear density, elongation at break, and dry heat shrinkage were not obvious. The breaking strength decreased by 0.3 cN / dtex, the CV value of evenness variation increased by 1.3%, and the downgrading rate of hairiness increased by 0.4%. This is because grooves were not provided on the inner wall of the cooling air cylinder, and reverse air flow was formed in the cooling air cylinder by the cooling air. The cooling air flow velocity in the cross-section direction of the cooling air cylinder was uneven, resulting in an increased difference in the cooling degree between different tows, uneven orientation and crystallization between tow molecules, leading to a decrease in breaking strength, an increase in the CV value of evenness variation, and the appearance of hairiness at the same draw ratio subsequently. This shows that the grooves have an important influence on evenness, breaking strength, and hairiness.

[0098] Comparative Example 3A

[0099] A preparation device for polyester industrial yarn, as Figure 10 shown, the tow coming out from the spinning box 1 enters the cooling air cylinder 10 after passing through the slow cooling zone 2 and the windless zone 3. After the cooling air 5 enters the cooling air cylinder 10 from the air supply pipeline 6, the flow direction of the cooling air 5 is perpendicular to the running direction of the tow 9.

[0100] Comparative Example 3B

[0101] A preparation method for polyester industrial yarn is basically the same as that of Example 1B, and the only difference is that: the preparation device for a polyester industrial yarn provided by Comparative Example 3A is adopted.

[0102] The polyester industrial yarn produced has a linear density of 420 dtex, 96 holes, a breaking strength of 8.3 cN / dtex, an elongation at break of 22%, a CV value of evenness variation of 0.8%, a dry heat shrinkage of 4.3%, a downgrading rate of hairiness of 1.1%, and a fiber flatness of 4.2.

[0103] Comparative Example 3B and Example 1B were compared. For the polyester industrial yarn produced in Comparative Example 3B, the change in linear density was not obvious, the breaking strength increased by 0.5 cN / dtex, the elongation at break decreased by 6%, the CV value of evenness variation increased by 0.3%, the dry heat shrinkage increased by 0.3%, and the downgrading rate of hairiness increased by 0.2%. This is because the cooling method with the flow direction of the cooling air perpendicular to the running direction of the tow was adopted, the tension on the tow increased, the orientation degree of the primary fiber molecules increased, and after subsequent stretching by the hot roller, the orientation degree of the overall molecular chain further increased. Although the breaking strength of the fiber increased, the elongation at break decreased and the dry heat shrinkage increased. This shows that the setting method of the flow direction of the cooling air and the running direction of the tow has an important influence on the elongation at break and dry heat shrinkage.

[0104] Example 2A

[0105] As Figures 1 - 3A preparation device for polyester industrial yarn for airbags as shown, which is composed of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, four wire guiding cylinders 4, a cross-shaped circular ring non-porous plate, a cross-shaped circular ring porous plate, a suction cylinder 8, a circular ring non-porous plate, a circular ring porous plate, a blowing air duct 6, a suction duct 7 and a spinning channel 11;

[0106] Both ends of the cooling air cylinder 10 are open, the cylinder wall has no holes, it is vertically arranged, is cylindrical, and is divided into upper, middle and lower sections;

[0107] Both ends of the four wire guiding cylinders 4 are open, the cylinder wall has no holes, they are vertically arranged inside the upper section of the cooling air cylinder 10. The upper ends of the four wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring non-porous plate. The lower ends of the four wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring porous plate. The cross-shaped circular ring is composed of a circular ring and a cross shape located therein. The cross shape equally divides the interior of the circular ring into four parts. The four wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-shaped circular ring non-porous plate and the cross-shaped circular ring porous plate jointly enclose a blowing air cavity; The cross-sections of the four wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0108] As Figure 4 shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air cylinder 10. The grooves are round pit grooves 13, which are arranged in a staggered dot matrix structure. The cooling air 5 generates small round pit groove refraction flows 14 at the round pit grooves 13. The diameter of the round pit grooves 13 is 4 mm, the groove depth is 2.5 mm, and the center distance between any two adjacent round pits is 9.5 mm;

[0109] Both ends of the suction cylinder 8 are open, the cylinder wall has no holes, it is vertically arranged inside the lower section of the cooling air cylinder 10 and is coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10 and the two are connected through a circular ring porous plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10 and the two are connected through a circular ring non-porous plate. The suction cylinder 8, the circular ring non-porous plate, the circular ring porous plate and the lower section of the cooling air cylinder 10 jointly enclose a suction cavity; The inner diameter of the cooling air cylinder 10 is 100 mm, the length of the upper section is 110 mm, the length of the middle section is 1150 mm, and the length of the lower section is 140 mm; The outer diameter of the wire guiding cylinder 4 is 60 mm smaller than the inner diameter of the cooling air cylinder 10; The outer diameter of the suction cylinder 8 is 60 mm smaller than the inner diameter of the cooling air cylinder 10;

[0110] The blowing air duct 6 is horizontally arranged and communicates with the blowing air cavity; The suction duct 7 is horizontally arranged and communicates with the suction cavity; The inner diameter of the blowing air duct 6 is 100 mm, and the inner diameter of the suction duct 7 is 100 mm;

[0111] The spinneret holes on the spinneret plate are rectangular, with a length-to-width ratio of 9:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively directly above the hollow parts of the 4 wire guiding cylinders 4.

[0112] The spinning box 1 is located above the cooling air cylinder 10. Between them are the slow cooling zone 2 and the windless zone 3. The slow cooling zone 2 is located above the windless zone 3. The filament bundle 9 coming out of the spinning box passes through the slow cooling zone 2 and the windless zone 3 and then enters the wire guiding cylinder 4. Then the filament bundle 9 enters the cooling air cylinder 10. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9. The height of the slow cooling zone 2 is 95 mm; the height of the windless zone 3 is 45 mm.

[0113] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it; the length of the spinning duct 11 is 700 mm.

[0114] Example 2B

[0115] A preparation method of polyester industrial yarn for airbag uses the preparation device of polyester industrial yarn for airbag in Example 2A above. The spinning process flow is: polyester melt is extruded through the spinneret plate → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rolls → shaped → texturized → wound.

[0116] The spinning process parameters are: ambient temperature 40 °C; spinning temperature 295 °C; slow cooling zone temperature 310 °C; cooling air temperature 35 °C; cooling air speed 0.6 m / s; suction force of the suction pipeline 0.2 Pa; speed of the first pair of hot rolls 490 m / min, temperature 60 °C; speed of the second pair of hot rolls 500 m / min, temperature 95 °C; speed of the third pair of hot rolls 1850 m / min, temperature 130 °C; speed of the fourth pair of hot rolls 2995 m / min, temperature 244 °C; speed of the fifth pair of hot rolls 2840 m / min, temperature 240 °C; speed of the sixth pair of hot rolls 2650 m / min, temperature 202 °C; total draw ratio 5.99, main draw ratio 3.70, secondary draw ratio 1.62; winding speed 2700 m / min; spinning tension 80 cN.

[0117] The polyester industrial yarn for airbag obtained has a linear density of 550 dtex, 144 holes, a breaking strength of 8 cN / dtex, a breaking elongation of 29%, a CV value of the evenness variation rate of 0.8%, a dry heat shrinkage rate of 4.12%, a downgrading rate of hairiness of 0.85%, and a fiber flatness of 3.5.

[0118] Example 3A

[0119] As Figures 1 - 3A preparation device for polyester industrial yarn for airbags as shown, which is composed of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, four wire guiding cylinders 4, a cross-shaped circular ring non-porous plate, a cross-shaped circular ring porous plate, a suction cylinder 8, an annular non-porous plate, an annular porous plate, a air supply pipe 6, a suction pipe 7 and a spinning channel 11;

[0120] Both ends of the cooling air cylinder 10 are open, the cylinder wall is non-porous, it is vertically arranged, and it is cylindrical, and is divided into upper, middle and lower sections;

[0121] Both ends of the four wire guiding cylinders 4 are open, the cylinder wall is non-porous, and they are vertically arranged in the upper section of the cooling air cylinder 10. The upper ends of the four wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected by a cross-shaped circular ring non-porous plate. The lower ends of the four wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected by a cross-shaped circular ring porous plate. The cross-shaped circular ring is composed of a circular ring and a cross shape located therein. The cross shape equally divides the inside of the circular ring into four parts. The four wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-shaped circular ring non-porous plate, and the cross-shaped circular ring porous plate jointly enclose an air supply cavity; The cross-sections of the four wire guiding cylinders 4 at each position are all fan-shaped and have the same size;

[0122] As Figure 4 shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air cylinder 10. The groove is a round pit groove 13, which is arranged in a staggered dot matrix structure. The cooling air 5 generates a small round pit groove refraction flow 14 at the round pit groove 13. The diameter of the round pit groove 13 is 3 mm, the groove depth is 2 mm, and the center distance between any two adjacent round pits is 10 mm;

[0123] Both ends of the suction cylinder 8 are open, the cylinder wall is non-porous, and it is vertically arranged in the lower section of the cooling air cylinder 10 and is coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10 and the two are connected by an annular porous plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10 and the two are connected by an annular non-porous plate. The suction cylinder 8, the annular non-porous plate, the annular porous plate, and the lower section of the cooling air cylinder 10 jointly enclose a suction cavity; The inner diameter of the cooling air cylinder 10 is 150 mm, the length of the upper section is 150 mm, the length of the middle section is 1100 mm, and the length of the lower section is 110 mm; The outer diameter of the wire guiding cylinder 4 is 40 mm smaller than the inner diameter of the cooling air cylinder 10; The outer diameter of the suction cylinder 8 is 40 mm smaller than the inner diameter of the cooling air cylinder 10;

[0124] The air supply pipe 6 is horizontally arranged and communicated with the air supply cavity; The suction pipe 7 is horizontally arranged and communicated with the suction cavity; The inner diameter of the air supply pipe 6 is 110 mm, and the inner diameter of the suction pipe 7 is 110 mm;

[0125] The spinneret holes on the spinneret are rectangular, with a length-to-width ratio of 10:1. The spinneret holes on the spinneret are distributed in 4 regions, and the 4 regions are respectively directly above the hollow parts of the 4 wire guiding cylinders 4.

[0126] The spinning box 1 is located above the cooling air cylinder 10, and there are a slow cooling zone 2 and a windless zone 3 between them. The slow cooling zone 2 is located above the windless zone 3. The filament bundle 9 coming out of the spinning box passes through the slow cooling zone 2 and the windless zone 3 and then enters the wire guiding cylinder 4, and then the filament bundle 9 enters the cooling air cylinder 10. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling zone 2 is 95 mm; the height of the windless zone 3 is 50 mm.

[0127] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it; the length of the spinning duct 11 is 600 mm.

[0128] Example 3B

[0129] A method for preparing polyester industrial yarn for airbags uses the preparation device for polyester industrial yarn for airbags in Example 3A above. The spinning process flow is: polyester melt is extruded through a spinneret → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → texturized → wound.

[0130] The spinning process parameters are: ambient temperature 36 °C; spinning temperature 300 °C; slow cooling zone temperature 295 °C; cooling air temperature 30 °C; cooling air speed 0.8 m / s; suction force of the suction pipeline 0.1 Pa; speed of the first pair of hot rollers 500 m / min, temperature 60 °C; speed of the second pair of hot rollers 510 m / min, temperature 95 °C; speed of the third pair of hot rollers 2030 m / min, temperature 130 °C; speed of the fourth pair of hot rollers 2870 m / min, temperature 245 °C; speed of the fifth pair of hot rollers 2720 m / min, temperature 244 °C; speed of the sixth pair of hot rollers 2550 m / min, temperature 190 °C; total draw ratio 5.63, main draw ratio 3.98, secondary draw ratio 1.41; winding speed 2600 m / min; spinning tension 70 cN.

[0131] The polyester industrial yarn for airbags obtained has a linear density of 420 dtex, 96 holes, a breaking strength of 7.6 cN / dtex, an elongation at break of 30%, a CV value of the evenness variation rate of 0.65%, a dry heat shrinkage rate of 4.08%, a downgrading rate of hairiness of 1%, and a fiber flatness of 4.2.

[0132] Example 4A

[0133] As Figures 1 - 3A preparation device for polyester industrial yarn for airbags shown in the figure is composed of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, four wire guiding cylinders 4, a cross-circular ring-shaped non-porous plate, a cross-circular ring-shaped porous plate, a suction cylinder 8, an annular non-porous plate, an annular porous plate, a blast pipe 6, a suction pipe 7 and a spinning channel 11;

[0134] Both ends of the cooling air cylinder 10 are open, the cylinder wall is non-porous, it is vertically arranged, is cylindrical, and is divided into upper, middle and lower sections;

[0135] Both ends of the four wire guiding cylinders 4 are open, the cylinder wall is non-porous, and they are vertically arranged in the upper section of the cooling air cylinder 10. The upper ends of the four wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-circular ring-shaped non-porous plate. The lower ends of the four wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-circular ring-shaped porous plate. The cross-circular ring is composed of a circular ring and a cross shape located therein. The cross shape equally divides the interior of the circular ring into four parts. The four wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-circular ring-shaped non-porous plate and the cross-circular ring-shaped porous plate jointly enclose a blast cavity; The cross-sections of the four wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0136] As Figure 5 and Figure 6 As shown in the figure, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air cylinder 10. The groove is a non-circular pit groove 15. The cooling air 5 generates a small non-circular pit groove refraction flow 16 at the non-circular pit groove 15. The non-circular pit groove 15 is a V-shaped groove. The non-circular pit groove 15 gradually shrinks in size from the groove opening to the groove bottom. The groove opening is oblong, the length of the oblong is 15 mm and the width is 3 mm. The groove bottom is in the shape of a line segment. The length of the groove bottom = the length of the oblong - the width of the oblong. The groove depth is 2.2 mm. The non-circular pit grooves 15 are divided into multiple groups. The non-circular pit grooves 15 in the same group are circumferentially spaced along the middle section of the cooling air cylinder 10 with a spacing of 6 mm. The non-circular pit grooves 15 in different groups are axially spaced along the middle section of the cooling air cylinder 10 with a spacing of 10 mm. For the same non-circular pit groove 15, the short axis of symmetry of the oblong and the perpendicular bisector of the line segment are both parallel to the axis of the cooling air cylinder 10. The straight line where the center of the oblong and the midpoint of the line segment are located is perpendicular to and intersects the central axis of the cooling air cylinder 10;

[0137] The two ends of the suction cylinder 8 are open, the cylinder wall has no holes, and it is vertically arranged coaxially inside the lower section of the cooling air cylinder 10. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10 and the two are connected by an annular perforated plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10 and the two are connected by an annular non-perforated plate. The suction cylinder 8, the annular non-perforated plate, the annular perforated plate, and the lower section of the cooling air cylinder 10 jointly enclose a suction cavity. The inner diameter of the cooling air cylinder 10 is 120 mm, the length of the upper section is 120 mm, the length of the middle section is 1200 mm, and the length of the lower section is 120 mm. The outer diameter of the wire traversing cylinder 4 is 50 mm smaller than the inner diameter of the cooling air cylinder 10. The outer diameter of the suction cylinder 8 is 50 mm smaller than the inner diameter of the cooling air cylinder 10.

[0138] The air supply duct 6 is horizontally arranged and communicated with the air supply cavity. The suction duct 7 is horizontally arranged and communicated with the suction cavity. The inner diameter of the air supply duct 6 is 120 mm, and the inner diameter of the suction duct 7 is 120 mm.

[0139] The spinneret holes on the spinneret plate are rectangular, and the length-width ratio is 7.1:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively located directly above the hollow parts of the 4 wire traversing cylinders 4.

[0140] The spinning box 1 is located above the cooling air cylinder 10. Between them are a slow cooling zone 2 and a windless zone 3. The slow cooling zone 2 is located above the windless zone 3. The filament bundle 9 coming out of the spinning box passes through the slow cooling zone 2 and the windless zone 3 and then enters the wire traversing cylinder 4, and then the filament bundle 9 enters the cooling air cylinder 10 again. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9. The height of the slow cooling zone 2 is 100 mm. The height of the windless zone 3 is 55 mm.

[0141] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it. The length of the spinning duct 11 is 650 mm.

[0142] Example 4B

[0143] A method for preparing polyester industrial yarn for airbags, using the preparation device for polyester industrial yarn for airbags in the above Example 4A, and the spinning process flow is: the polyester melt is extruded through the spinneret plate → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → networked → wound.

[0144] The spinning process parameters are as follows: ambient temperature 37°C; spinning temperature 305°C; temperature in the slow cooling zone 295°C; cooling air temperature 32°C; cooling air velocity 0.9 m / s; suction force in the suction pipeline 0.08 Pa; speed of the first pair of hot rollers 560 m / min, temperature 65°C; speed of the second pair of hot rollers 565 m / min, temperature 90°C; speed of the third pair of hot rollers 2150 m / min, temperature 123°C; speed of the fourth pair of hot rollers 3600 m / min, temperature 210°C; speed of the fifth pair of hot rollers 3620 m / min, temperature 210°C; speed of the sixth pair of hot rollers 3420 m / min, temperature 180°C; total draw ratio 6.37, primary draw ratio 3.81, secondary draw ratio 1.67; winding speed 3610 m / min; spinning tension 75 cN.

[0145] The polyester industrial yarn for airbag prepared has a linear density of 440 dtex, 144 holes, breaking strength of 7.9 cN / dtex, breaking elongation of 32%, CV value of evenness variation of 0.9%, dry heat shrinkage rate of 4.14%, downgrading rate of hairiness of 0.95%, and fiber flatness of 4.

[0146] Example 5A

[0147] As Figures 1 - 3 shown, a preparation device for polyester industrial yarn for airbag consists of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, 4 wire guiding cylinders 4, a cross-shaped circular non-porous plate, a cross-shaped circular porous plate, a suction cylinder 8, a circular non-porous plate, a circular porous plate, a air supply pipeline 6, a suction pipeline 7, and a spinning channel 11;

[0148] Both ends of the cooling air cylinder 10 are open, the cylinder wall is non-porous, it is vertically arranged, and is cylindrical, divided into upper, middle and lower sections;

[0149] Both ends of the 4 wire guiding cylinders 4 are open, the cylinder wall is non-porous, and they are vertically arranged inside the upper section of the cooling air cylinder 10. The upper ends of the 4 wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular non-porous plate. The lower ends of the 4 wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular porous plate. The cross-shaped circular is composed of a circular ring and a cross shape located therein. The cross shape equally divides the inside of the circular ring into four parts. The 4 wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-shaped circular non-porous plate, and the cross-shaped circular porous plate together enclose an air supply cavity; The cross-sections of the 4 wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0150] As Figure 5 and Figure 6As shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air duct 10 are provided on the inner wall of the middle section of the cooling air duct 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows over the inner wall surface of the cooling air duct 10. The grooves are non-circular pit grooves 15. Small non-circular pit groove refraction flows 16 are generated at the non-circular pit grooves 15 by the cooling air 5. The non-circular pit grooves 15 are a type of V-shaped grooves. The dimensions of the non-circular pit grooves 15 gradually decrease from the groove opening to the groove bottom. The groove opening is oblong, with a length of 9 mm and a width of 3.5 mm. The groove bottom is in the shape of a line segment, and the length of the groove bottom = the length of the oblong - the width of the oblong. The groove depth is 2.1 mm. The non-circular pit grooves 15 are divided into multiple groups. The non-circular pit grooves 15 in the same group are circumferentially spaced along the middle section of the cooling air duct 10 with a spacing of 5 mm, and the non-circular pit grooves 15 in different groups are axially spaced along the middle section of the cooling air duct 10 with a spacing of 9.5 mm. For the same non-circular pit groove 15, the short axis of symmetry of the oblong and the perpendicular bisector of the line segment are both parallel to the axial direction of the cooling air duct 10, and the straight line where the center of the oblong and the midpoint of the line segment are located is perpendicular to and intersects the central axis of the cooling air duct 10;

[0151] Both ends of the suction cylinder 8 are open, and the cylinder wall has no holes. It is vertically arranged inside the lower section of the cooling air duct 10 and is coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air duct 10 and they are connected by an annular perforated plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air duct 10 and they are connected by an annular non-perforated plate. The suction cylinder 8, the annular non-perforated plate, the annular perforated plate, and the lower section of the cooling air duct 10 jointly enclose a suction chamber; the inner diameter of the cooling air duct 10 is 140 mm, the length of the upper section is 150 mm, the length of the middle section is 1000 mm, and the length of the lower section is 150 mm; the outer diameter of the wire traversing cylinder 4 is 50 mm smaller than the inner diameter of the cooling air duct 10; the outer diameter of the suction cylinder 8 is 50 mm smaller than the inner diameter of the cooling air duct 10;

[0152] The air supply duct 6 is horizontally arranged and communicates with the air supply chamber; the suction duct 7 is horizontally arranged and communicates with the suction chamber; the inner diameter of the air supply duct 6 is 120 mm, and the inner diameter of the suction duct 7 is 120 mm;

[0153] The spinneret holes on the spinneret plate are rectangular, with a length-to-width ratio of 8:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively located directly above the hollow parts of the 4 wire traversing cylinders 4;

[0154] The spinning box 1 is located above the cooling air duct 10. Between them are a slow cooling zone 2 and a windless zone 3. The slow cooling zone 2 is located above the windless zone 3; the filament bundle 9 coming out of the spinning box passes through the slow cooling zone 2 and the windless zone 3 and then enters the wire traversing cylinder 4, and then the filament bundle 9 enters the cooling air duct 10. The flow direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling zone 2 is 105 mm; the height of the windless zone 3 is 45 mm;

[0155] The spinning duct 11 is located below and connected to the cooling air cylinder 10; the length of the spinning duct 11 is 650 mm.

[0156] Example 5B

[0157] A method for preparing polyester industrial yarn for airbag uses the preparation device for polyester industrial yarn for airbag as described in Example 5A above. The spinning process flow is: the polyester melt is extruded through a spinneret plate → cooled in a slow cooling zone → cooled in a windless zone → cooled by a cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → texturized → wound.

[0158] The spinning process parameters are: ambient temperature 39°C; spinning temperature 305°C; slow cooling zone temperature 305°C; cooling air temperature 35°C; cooling air velocity 0.8 m / s; suction force of the suction pipeline 0.06 Pa; speed of the first pair of hot rollers 430 m / min, temperature 65°C; speed of the second pair of hot rollers 450 m / min, temperature 100°C; speed of the third pair of hot rollers 1900 m / min, temperature 125°C; speed of the fourth pair of hot rollers 2650 m / min, temperature 220°C; speed of the fifth pair of hot rollers 2580 m / min, temperature 225°C; speed of the sixth pair of hot rollers 2380 m / min, temperature 190°C; total draw ratio 5.89, main draw ratio 4.22, secondary draw ratio 1.39; winding speed 2550 m / min; spinning tension 62 cN.

[0159] The polyester industrial yarn for airbag prepared has a linear density of 600 dtex, 144 holes, breaking strength of 8.1 cN / dtex, breaking elongation of 30%, CV value of evenness variation of 0.75%, dry heat shrinkage rate of 4.1%, downgrading rate of hairiness of 0.88%, and fiber flatness of 3.8.

[0160] Example 6A

[0161] As Figures 1 - 3 shown, a preparation device for polyester industrial yarn for airbag consists of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, 4 wire guiding cylinders 4, a cross-shaped circular ring non-porous plate, a cross-shaped circular ring porous plate, a suction cylinder 8, a circular ring non-porous plate, a circular ring porous plate, a air supply pipeline 6, a suction pipeline 7, and a spinning duct 11.

[0162] Both ends of the cooling air cylinder 10 are open, the cylinder wall has no holes, it is vertically arranged, is cylindrical, and is divided into upper, middle, and lower sections.

[0163] Both ends of the four wire guiding cylinders 4 are open, the cylinder walls are poreless, and they are vertically arranged in the upper section of the cooling air cylinder 10. The upper ends of the four wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10, and the five are connected by a cross-circular poreless plate. The lower ends of the four wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10, and the five are connected by a cross-circular perforated plate. The cross-circular shape consists of a circular shape and a cross shape located therein. The cross shape equally divides the interior of the circular shape into four parts. The four wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-circular poreless plate, and the cross-circular perforated plate jointly enclose a air supply cavity; The cross-sections of the four wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0164] As Figure 5 and Figure 6 shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air cylinder 10. The groove is a non-circular pit groove 15. The cooling air 5 generates a small non-circular pit groove refraction flow 16 at the non-circular pit groove 15. The non-circular pit groove 15 is a V-shaped groove. The size of the non-circular pit groove 15 gradually decreases from the groove opening to the groove bottom. The groove opening is oblong, with a length of 11 mm and a width of 3.5 mm. The groove bottom is in the shape of a line segment, and the length of the groove bottom = the length of the oblong - the width of the oblong. The groove depth is 2.5 mm. The non-circular pit grooves 15 are divided into multiple groups. The non-circular pit grooves 15 in the same group are circumferentially spaced along the middle section of the cooling air cylinder 10 with a spacing of 4 mm. The non-circular pit grooves 15 in different groups are axially spaced along the middle section of the cooling air cylinder 10 with a spacing of 10 mm. For the same non-circular pit groove 15, the short axis of symmetry of the oblong and the perpendicular bisector of the line segment are both parallel to the axis of the cooling air cylinder 10. The straight line where the center of the oblong and the midpoint of the line segment are located is perpendicular to and intersects the central axis of the cooling air cylinder 10;

[0165] Both ends of the suction cylinder 8 are open, the cylinder wall is poreless, and it is vertically arranged in the lower section of the cooling air cylinder 10 and coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10, and the two are connected by an annular perforated plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10, and the two are connected by an annular poreless plate. The suction cylinder 8, the annular poreless plate, the annular perforated plate, and the lower section of the cooling air cylinder 10 jointly enclose a suction cavity; The inner diameter of the cooling air cylinder 10 is 120 mm, the length of the upper section is 110 mm, the length of the middle section is 1200 mm, and the length of the lower section is 140 mm; The outer diameter of the wire guiding cylinder 4 is 40 mm smaller than the inner diameter of the cooling air cylinder 10; The outer diameter of the suction cylinder 8 is 40 mm smaller than the inner diameter of the cooling air cylinder 10;

[0166] The air supply pipe 6 is horizontally arranged and communicates with the air supply cavity; The suction pipe 7 is horizontally arranged and communicates with the suction cavity; The inner diameter of the air supply pipe 6 is 110 mm, and the inner diameter of the suction pipe 7 is 110 mm;

[0167] The spinneret holes on the spinneret are rectangular, with a length-to-width ratio of 9:1. The spinneret holes on the spinneret are distributed in 4 regions, and the 4 regions are respectively directly above the hollow parts of the 4 wire guiding cylinders 4.

[0168] The spinning box 1 is located above the cooling air cylinder 10, and between them are the slow cooling zone 2 and the windless zone 3. The slow cooling zone 2 is located above the windless zone 3. The filament bundle 9 coming out of the spinning box passes through the slow cooling zone 2 and the windless zone 3 and then enters the wire guiding cylinder 4, and then the filament bundle 9 enters the cooling air cylinder 10. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling zone 2 is 105 mm; the height of the windless zone 3 is 50 mm.

[0169] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it; the length of the spinning duct 11 is 600 mm.

[0170] Example 6B

[0171] A method for preparing polyester industrial yarn for airbags, using the preparation device for polyester industrial yarn for airbags in Example 6A above, and the spinning process flow is: the polyester melt is extruded through the spinneret → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → texturized → wound.

[0172] The spinning process parameters are: ambient temperature 40 °C; spinning temperature 310 °C; slow cooling zone temperature 320 °C; cooling air temperature 33 °C; cooling air speed 1.0 m / s; suction force of the suction pipeline 0.2 Pa; speed of the first pair of hot rollers 460 m / min, temperature 70 °C; speed of the second pair of hot rollers 580 m / min, temperature 90 °C; speed of the third pair of hot rollers 2260 m / min, temperature 135 °C; speed of the fourth pair of hot rollers 3200 m / min, temperature 235 °C; speed of the fifth pair of hot rollers 3100 m / min, temperature 240 °C; speed of the sixth pair of hot rollers 2950 m / min, temperature 220 °C; total draw ratio 5.52, main draw ratio 3.90, secondary draw ratio 1.42; winding speed 3050 m / min; spinning tension 75 cN.

[0173] The polyester industrial yarn for airbags prepared has a linear density of 550 dtex, 96 holes, a breaking strength of 7.8 cN / dtex, a breaking elongation rate of 31%, a CV value of the evenness variation of 0.6%, a dry heat shrinkage rate of 4.04%, a downgrading rate of hairiness of 1.1%, and a fiber flatness of 3.6.

[0174] Example 7A

[0175] As Figures 1 - 3A preparation device for polyester industrial yarn for airbags shown in the figure consists of a spinning box 1, a spinneret plate, a cooling air cylinder 10, four wire guiding cylinders 4, a cross-shaped circular ring-shaped non-porous plate, a cross-shaped circular ring-shaped porous plate, a suction cylinder 8, a circular ring-shaped non-porous plate, a circular ring-shaped porous plate, a air supply duct 6, a suction duct 7 and a spinning channel 11;

[0176] Both ends of the cooling air cylinder 10 are open, the cylinder wall is non-porous, it is vertically arranged, and it is cylindrical, divided into upper, middle and lower sections;

[0177] Both ends of the four wire guiding cylinders 4 are open, the cylinder wall is non-porous, and they are vertically arranged inside the upper section of the cooling air cylinder 10. The upper ends of the four wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring-shaped non-porous plate. The lower ends of the four wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring-shaped porous plate. The cross-shaped circular ring is composed of a circular ring and a cross shape located therein. The cross shape equally divides the inside of the circular ring into four parts. The four wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-shaped circular ring-shaped non-porous plate, and the cross-shaped circular ring-shaped porous plate together enclose an air supply cavity; The cross-sections of the four wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0178] As Figure 5 and Figure 7 shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air cylinder 10. The groove is a non-circular pit groove 15. The cooling air 5 generates a small non-circular pit groove refraction flow 16 at the non-circular pit groove 15. The non-circular pit groove 15 is an inverted isosceles trapezoid groove. The size of the non-circular pit groove 15 gradually shrinks from the groove opening to the groove bottom. The groove opening is an oval shape, the length of the oval shape is 20 mm and the width is 4 mm. The groove bottom is a rectangle, the groove depth is 2.2 mm, and the angle θ between the groove wall and the central axis of the non-circular pit groove 15 is 30°. The non-circular pit grooves 15 are divided into multiple groups. The non-circular pit grooves 15 in the same group are circumferentially spaced along the middle section of the cooling air cylinder 10 and the spacing is 5 mm. The non-circular pit grooves 15 in different groups are axially spaced along the middle section of the cooling air cylinder 10 and the spacing is 9 mm. For the same non-circular pit groove 15, the short symmetry axes of the oval shape and the rectangle are both parallel to the axis of the cooling air cylinder 10, and the straight line where the centers of the oval shape and the rectangle are located together is perpendicular to and intersects the central axis of the cooling air cylinder 10;

[0179] The two ends of the suction cylinder 8 are open, the cylinder wall has no holes, and it is vertically arranged coaxially inside the lower section of the cooling air cylinder 10. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10 and the two are connected by an annular perforated plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10 and the two are connected by an annular non-perforated plate. The suction cylinder 8, the annular non-perforated plate, the annular perforated plate, and the lower section of the cooling air cylinder 10 together enclose a suction cavity; the inner diameter of the cooling air cylinder 10 is 200 mm, the length of the upper section is 140 mm, the length of the middle section is 1150 mm, and the length of the lower section is 110 mm; the outer diameter of the wire traversing cylinder 4 is 50 mm smaller than the inner diameter of the cooling air cylinder 10; the outer diameter of the suction cylinder 8 is 50 mm smaller than the inner diameter of the cooling air cylinder 10;

[0180] The air supply duct 6 is horizontally arranged and communicates with the air supply cavity; the suction duct 7 is horizontally arranged and communicates with the suction cavity; the inner diameter of the air supply duct 6 is 120 mm, and the inner diameter of the suction duct 7 is 120 mm;

[0181] The spinneret holes on the spinneret plate are rectangular, and the aspect ratio of the length to the width is 10:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively directly above the hollow parts of the 4 wire traversing cylinders 4;

[0182] The spinning box 1 is located above the cooling air cylinder 10, and between them are the slow cooling zone 2 and the windless zone 3. The slow cooling zone 2 is located above the windless zone 3; the filament bundle 9 coming out of the spinning box enters the wire traversing cylinder 4 after passing through the slow cooling zone 2 and the windless zone 3, and then the filament bundle 9 enters the cooling air cylinder 10. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling zone 2 is 95 mm; the height of the windless zone 3 is 45 mm;

[0183] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it; the length of the spinning duct 11 is 700 mm.

[0184] Example 7B

[0185] A method for preparing polyester industrial yarn for airbags uses the preparation device for polyester industrial yarn for airbags in the above Example 7A. The spinning process flow is: the polyester melt is extruded through the spinneret plate → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → networked → wound;

[0186] The spinning process parameters are as follows: ambient temperature 36°C; spinning temperature 300°C; temperature in the slow cooling zone 310°C; cooling air temperature 34°C; cooling air velocity 0.5 m / s; suction force in the suction pipeline 0.15 Pa; speed of the first pair of hot rollers 480 m / min, temperature 65°C; speed of the second pair of hot rollers 500 m / min, temperature 95°C; speed of the third pair of hot rollers 2100 m / min, temperature 132°C; speed of the fourth pair of hot rollers 3000 m / min, temperature 245°C; speed of the fifth pair of hot rollers 2900 m / min, temperature 245°C; speed of the sixth pair of hot rollers 2700 m / min, temperature 205°C; total draw ratio 6.00, primary draw ratio 4.20, secondary draw ratio 1.43; winding speed 2800 m / min; spinning tension 65 cN.

[0187] The polyester industrial yarn for airbags prepared has a linear density of 450 dtex, 144 holes, a breaking strength of 8 cN / dtex, an elongation at break of 30%, a CV value of evenness variation of 0.9%, a dry heat shrinkage rate of 4%, a downgrading rate of hairiness of 1.12%, and a fiber flatness of 3.9.

[0188] Example 8A

[0189] As Figures 1 - 3 shown, a preparation device for polyester industrial yarn for airbags consists of a spinning box body 1, a spinneret plate, a cooling air cylinder 10, 4 wire guiding cylinders 4, a cross-shaped circular ring non-porous plate, a cross-shaped circular ring porous plate, a suction cylinder 8, an annular non-porous plate, an annular porous plate, a air supply pipeline 6, a suction pipeline 7, and a spinning channel 11;

[0190] Both ends of the cooling air cylinder 10 are open, the cylinder wall has no holes, it is vertically arranged, is cylindrical, and is divided into upper, middle, and lower sections;

[0191] Both ends of the 4 wire guiding cylinders 4 are open, the cylinder wall has no holes, they are vertically arranged inside the upper section of the cooling air cylinder 10. The upper ends of the 4 wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring non-porous plate. The lower ends of the 4 wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10 and the five are connected through a cross-shaped circular ring porous plate. The cross-shaped circular ring consists of a circular ring and a cross shape located therein. The cross shape equally divides the interior of the circular ring into four parts. The 4 wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-shaped circular ring non-porous plate, and the cross-shaped circular ring porous plate jointly enclose an air supply chamber; the cross-sections of the 4 wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0192] As Figure 5 and Figure 7As shown in the figure, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air duct 10 are provided on the inner wall of the middle section of the cooling air duct 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows through the inner wall surface of the cooling air duct 10. The grooves are non-circular pit grooves 15. Small non-circular pit groove refraction flows 16 are generated at the non-circular pit grooves 15 by the cooling air 5. The non-circular pit groove 15 is an inverted equal-height trapezoidal groove. The size of the non-circular pit groove 15 gradually shrinks from the groove opening to the groove bottom. The groove opening is an oblong shape, with a length of 10 mm and a width of 3.6 mm. The groove bottom is a rectangle, with a groove depth of 2 mm. The angle θ between the groove wall and the central axis of the non-circular pit groove 15 is 20°. The non-circular pit grooves 15 are divided into multiple groups. The non-circular pit grooves 15 in the same group are circumferentially spaced along the middle section of the cooling air duct 10 with a spacing of 6 mm, and the non-circular pit grooves 15 in different groups are axially spaced along the middle section of the cooling air duct 10 with a spacing of 9.5 mm. For the same non-circular pit groove 15, the short symmetry axes of the oblong shape and the rectangle are both parallel to the axial direction of the cooling air duct 10, and the straight line where the centers of the oblong shape and the rectangle are located together is perpendicular to and intersects the central axis of the cooling air duct 10;

[0193] Both ends of the suction cylinder 8 are open, the cylinder wall has no holes, and it is vertically arranged inside the lower section of the cooling air duct 10 and coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air duct 10 and they are connected by an annular perforated plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air duct 10 and they are connected by an annular non-perforated plate. The suction cylinder 8, the annular non-perforated plate, the annular perforated plate, and the lower section of the cooling air duct 10 together enclose a suction cavity; the inner diameter of the cooling air duct 10 is 110 mm, the length of the upper section is 130 mm, the length of the middle section is 1100 mm, and the length of the lower section is 150 mm; the outer diameter of the wire guiding cylinder 4 is 60 mm smaller than the inner diameter of the cooling air duct 10; the outer diameter of the suction cylinder 8 is 60 mm smaller than the inner diameter of the cooling air duct 10;

[0194] The air supply duct 6 is horizontally arranged and communicates with the air supply cavity; the suction duct 7 is horizontally arranged and communicates with the suction cavity; the inner diameter of the air supply duct 6 is 110 mm, and the inner diameter of the suction duct 7 is 110 mm;

[0195] The spinneret holes on the spinneret plate are rectangular, with an aspect ratio of 7.1:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively located directly above the hollow parts of the 4 wire guiding cylinders 4;

[0196] The spinning box body 1 is located above the cooling air duct 10. There are a slow cooling area 2 and a windless area 3 between them. The slow cooling area 2 is located above the windless area 3; the filament bundle 9 coming out of the spinning box body passes through the slow cooling area 2 and the windless area 3 and then enters the wire guiding cylinder 4, and then the filament bundle 9 enters the cooling air duct 10 again. The flow direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling area 2 is 100 mm; the height of the windless area 3 is 55 mm;

[0197] The spinning duct 11 is located below and connected to the cooling air cylinder 10; the length of the spinning duct 11 is 700 mm.

[0198] Example 8B

[0199] A method for preparing polyester industrial yarn for airbag, using the preparation device for polyester industrial yarn for airbag in Example 8A above, the spinning process flow is: the polyester melt is extruded through the spinneret → cooled in the slow cooling zone → cooled in the windless zone → cooled by the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → texturized → wound;

[0200] The spinning process parameters are: ambient temperature 38 °C; spinning temperature 291 °C; slow cooling zone temperature 290 °C; cooling air temperature 35 °C; cooling air speed 0.8 m / s; suction force of the suction pipeline 0.18 Pa; speed of the first pair of hot rollers 540 m / min, temperature 70 °C; speed of the second pair of hot rollers 550 m / min, temperature 100 °C; speed of the third pair of hot rollers 2050 m / min, temperature 128 °C; speed of the fourth pair of hot rollers 3500 m / min, temperature 250 °C; speed of the fifth pair of hot rollers 3400 m / min, temperature 250 °C; speed of the sixth pair of hot rollers 3200 m / min, temperature 215 °C; total draw ratio 6.36, main draw ratio 3.73, secondary draw ratio 1.71; winding speed 3450 m / min; spinning tension 68 cN.

[0201] The polyester industrial yarn for airbag obtained has a linear density of 560 dtex, 96 holes, a breaking strength of 7.9 cN / dtex, a breaking elongation rate of 29%, a CV value of the evenness variation of 1%, a dry heat shrinkage rate of 4.1%, a downgrading rate of hairiness of 1.05%, and a fiber flatness of 3.65.

[0202] Example 9A

[0203] As Figures 1 - 3 shown, a preparation device for polyester industrial yarn for airbag is composed of a spinning box body 1, a spinneret, a cooling air cylinder 10, 4 wire guiding cylinders 4, a cross-shaped circular ring non-porous plate, a cross-shaped circular ring porous plate, a suction cylinder 8, a circular ring non-porous plate, a circular ring porous plate, a air supply pipeline 6, a suction pipeline 7 and a spinning duct 11;

[0204] Both ends of the cooling air cylinder 10 are open, the cylinder wall has no holes, it is vertically arranged, is cylindrical, and is divided into upper, middle and lower sections;

[0205] The two ends of the four wire guiding cylinders 4 are open, the cylinder walls are without holes, and they are vertically arranged in the upper section of the cooling air cylinder 10. The upper ends of the four wire guiding cylinders 4 are flush with the upper end of the upper section of the cooling air cylinder 10, and the five are connected by a cross-circular ring-shaped holeless plate. The lower ends of the four wire guiding cylinders 4 are flush with the lower end of the upper section of the cooling air cylinder 10, and the five are connected by a cross-circular ring-shaped perforated plate. The cross-circular ring shape consists of a circular ring and a cross shape located therein. The cross shape equally divides the interior of the circular ring into four parts. The four wire guiding cylinders 4, the upper section of the cooling air cylinder 10, the cross-circular ring-shaped holeless plate, and the cross-circular ring-shaped perforated plate jointly enclose an air supply cavity; the cross sections of the four wire guiding cylinders 4 at various positions are all fan-shaped and have the same size;

[0206] As Figure 5 and Figure 7 shown, a plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder 10 are provided on the inner wall of the middle section of the cooling air cylinder 10. The boundary layer is a fluid layer formed due to viscous action when the cooling air 5 flows over the inner wall surface of the cooling air cylinder 10. The grooves are non-circular pit grooves 15. Small non-circular pit groove refraction flows 16 are generated at the non-circular pit grooves 15 by the cooling air 5. The non-circular pit groove 15 is an inverted equal-height trapezoidal groove. The size of the non-circular pit groove 15 gradually decreases from the groove opening to the groove bottom. The groove opening is oblong, with a length of 14 mm and a width of 3.8 mm. The groove bottom is rectangular, with a groove depth of 2.5 mm. The angle θ between the groove wall and the central axis of the non-circular pit groove 15 is 25°. The non-circular pit grooves 15 are divided into multiple groups. The non-circular pit grooves 15 in the same group are circumferentially spaced along the middle section of the cooling air cylinder 10 with a spacing of 4 mm, and the non-circular pit grooves 15 in different groups are axially spaced along the middle section of the cooling air cylinder 10 with a spacing of 9 mm. For the same non-circular pit groove 15, the short symmetry axes of the oblong shape and the rectangular shape are both parallel to the axis of the cooling air cylinder 10, and the straight line where the centers of the oblong shape and the rectangular shape are located together is perpendicular to and intersects the central axis of the cooling air cylinder 10;

[0207] The two ends of the suction cylinder 8 are open, the cylinder wall is without holes, and it is vertically arranged in the lower section of the cooling air cylinder 10 and coaxial with it. The upper end of the suction cylinder 8 is flush with the upper end of the lower section of the cooling air cylinder 10, and the two are connected by an annular perforated plate. The lower end of the suction cylinder 8 is flush with the lower end of the lower section of the cooling air cylinder 10, and the two are connected by an annular holeless plate. The suction cylinder 8, the annular holeless plate, the annular perforated plate, and the lower section of the cooling air cylinder 10 jointly enclose a suction cavity; the inner diameter of the cooling air cylinder 10 is 160 mm, the length of the upper section is 120 mm, the length of the middle section is 1000 mm, and the length of the lower section is 120 mm; the outer diameter of the wire guiding cylinder 4 is 60 mm smaller than the inner diameter of the cooling air cylinder 10; the outer diameter of the suction cylinder 8 is 60 mm smaller than the inner diameter of the cooling air cylinder 10;

[0208] The air supply duct 6 is horizontally arranged and communicates with the air supply chamber; the suction duct 7 is horizontally arranged and communicates with the suction chamber; the inner diameter of the air supply duct 6 is 100 mm, and the inner diameter of the suction duct 7 is 100 mm;

[0209] The spinneret holes on the spinneret plate are rectangular, with a length-to-width ratio of 8:1. The spinneret holes on the spinneret plate are distributed in 4 regions, and the 4 regions are respectively located directly above the hollow parts of the 4 wire guiding cylinders 4;

[0210] The spinning box 1 is located above the cooling air cylinder 10, and between them are the slow cooling zone 2 and the windless zone 3. The slow cooling zone 2 is located above the windless zone 3. The filament bundle 9 coming out of the spinning box passes through the slow cooling zone 2 and the windless zone 3 and then enters the wire guiding cylinder 4, and then the filament bundle 9 enters the cooling air cylinder 10. The flowing direction of the cooling air 5 is parallel to the running direction of the filament bundle 9; the height of the slow cooling zone 2 is 105 mm; the height of the windless zone 3 is 50 mm;

[0211] The spinning duct 11 is located below the cooling air cylinder 10 and is connected to it; the length of the spinning duct 11 is 650 mm.

[0212] Example 9B

[0213] A method for preparing a polyester industrial yarn for airbags, using the preparation device for a polyester industrial yarn for airbags in Example 9A above. The spinning process flow is: the polyester melt is extruded through the spinneret plate → cooled in the slow cooling zone → cooled in the windless zone → cooled in the cooling air cylinder → oiling → stretched by six pairs of hot rollers → shaped → texturized → wound;

[0214] The spinning process parameters are: ambient temperature 35°C; spinning temperature 310°C; slow cooling zone temperature 300°C; cooling air temperature 30°C; cooling air speed 0.9 m / s; suction force of the suction duct 0.15 Pa; speed of the first pair of hot rollers 470 m / min, temperature 60°C; speed of the second pair of hot rollers 490 m / min, temperature 90°C; speed of the third pair of hot rollers 1950 m / min, temperature 135°C; speed of the fourth pair of hot rollers 3100 m / min, temperature 250°C; speed of the fifth pair of hot rollers 3000 m / min, temperature 248°C; speed of the sixth pair of hot rollers 2800 m / min, temperature 206°C; total draw ratio 6.33, main draw ratio 3.98, secondary draw ratio 1.59; winding speed 3000 m / min; spinning tension 74 cN.

[0215] The polyester industrial yarn for airbags prepared has a linear density of 550 dtex, 144 holes, a breaking strength of 8 cN / dtex, a breaking elongation rate of 31%, a CV value of the evenness variation rate of 0.86%, a dry heat shrinkage rate of 4.15%, a rate of downgrading due to hairiness of 1.08%, and a fiber flatness of 3.45.

Claims

1. A preparation device for polyester industrial yarn for airbags, characterized in that, It includes a spinneret plate, a cooling air cylinder (10), four wire guiding cylinders (4), a cross-shaped circular non-porous plate, a cross-shaped circular porous plate, a suction cylinder (8), a circular non-porous plate, a circular porous plate, an air supply duct (6) and a suction duct (7); The cooling air cylinder (10), the four wire guiding cylinders (4) and the suction cylinder (8) are all open at both ends, have no holes in the cylinder wall, and are vertically arranged; The cooling air cylinder (10) is cylindrical and is divided into upper, middle and lower sections; The four wire guiding cylinders (4) are inside the upper section, the upper ends are flush with the upper end of the upper section and the five are connected by the cross-shaped circular non-porous plate, and the lower ends are flush with the lower end of the upper section and the five are connected by the cross-shaped circular porous plate. The cross-shaped circular shape consists of a circular shape and a cross shape located therein. The four wire guiding cylinders (4), the upper section, the cross-shaped circular non-porous plate and the cross-shaped circular porous plate together enclose an air supply cavity; A plurality of grooves for suppressing the separation of the boundary layer from the cooling air cylinder (10) are provided on the inner wall of the middle section. The boundary layer is a fluid layer formed due to viscous action when the cooling air (5) flows through the inner wall surface of the cooling air cylinder (10); The suction cylinder (8) is inside the lower section and is coaxial with it. The upper end is flush with the upper end of the lower section and the two are connected by the circular porous plate. The lower end is flush with the lower end of the lower section and the two are connected by the circular non-porous plate. The suction cylinder (8), the circular non-porous plate, the circular porous plate and the lower section together enclose a suction cavity; The air supply duct (6) is horizontally arranged and communicates with the air supply cavity; the suction duct (7) is horizontally arranged and communicates with the suction cavity; The spinneret holes on the spinneret plate are distributed in four regions, and the four regions are respectively located directly above the hollow parts of the four wire guiding cylinders (4).

2. The preparation device of the polyester industrial yarn for airbag according to claim 1, characterized in that, The cross divides the inside of the circular shape into four equal parts; the cross-sections of the four wire guiding cylinders (4) at various positions are all fan-shaped and have the same size; the spinneret holes on the spinneret plate are rectangular, and the aspect ratio of length to width is 7.1 - 10:

1.

3. The preparation device of the polyester industrial yarn for airbag according to claim 1, characterized in that, The grooves are round pit grooves (13) and are arranged in a staggered dot matrix structure; the diameter of the round pit grooves (13) is 3 - 4 mm, the groove depth is 2 - 2.5 mm, and the center distance between any two adjacent round pits is 9 - 10 mm.

4. The preparation device of the polyester industrial yarn for airbag according to claim 1, characterized in that, The grooves are non-round pit grooves (15) and are divided into multiple groups. The same group of non-round pit grooves (15) are distributed along the circumferential pitch of the middle section and the pitch is 4 - 6 mm. Different groups of non-round pit grooves (15) are distributed along the axial pitch of the middle section and the pitch is 9 - 10 mm; The non-round pit grooves (15) gradually shrink in size from the groove opening to the groove bottom. The groove opening is oblong, the length of the oblong is 9 - 20 mm and the width of the oblong is 3 - 4 mm. The groove bottom is in the shape of a line segment or a rectangle, and the groove depth is 2 - 2.5 mm; When the bottom of the groove is rectangular, the included angle between the groove wall and the central axis of the non-circular pit groove (15) θ is 20 - 30°; For the same non-round pit groove (15), the short symmetry axis of the oblong, the perpendicular bisector of the line segment shape, and the short symmetry axis of the rectangle shape are all parallel to the axis of the cooling air cylinder (10). The straight line where the center of the oblong and the midpoint of the line segment shape or the center of the rectangle shape are located is perpendicular to and intersects the central axis of the cooling air cylinder (10).

5. The preparation device of the polyester industrial yarn for the airbag according to claim 1, characterized in that, The inner diameter of the cooling air cylinder (10) is 100 - 200 mm, the length of the upper section is 110 - 150 mm, the length of the middle section is 1000 - 1200 mm, and the length of the lower section is 110 - 150 mm.

6. The preparation device of the polyester industrial yarn for airbag according to claim 5, characterized in that, The outer diameter of the wire take-up bobbin (4) is 40 - 60 mm smaller than the inner diameter of the cooling air cylinder (10).

7. The preparation device of the polyester industrial yarn for airbag according to claim 5, characterized in that, The outer diameter of the suction cylinder (8) is 40 - 60 mm smaller than the inner diameter of the cooling air cylinder (10).

8. The preparation device of the polyester industrial yarn for airbag according to claim 5, characterized in that, The inner diameter of the air supply duct (6) is 100 - 120 mm, and the inner diameter of the suction duct (7) is 100 - 120 mm.

9. The preparation device of the polyester industrial yarn for airbag according to claim 1, characterized in that, It also includes a spinning box body (1). The spinning box body (1) is located above the cooling air cylinder (10). Between them are a slow cooling zone (2) and a windless zone (3). The slow cooling zone (2) is located above the windless zone (3).

10. The preparation device for polyester industrial yarn for airbag according to claim 9, characterized in that, The height of the slow cooling zone (2) is 95 - 105 mm; the height of the windless zone (3) is 45 - 55 mm.

11. The preparation device of the polyester industrial yarn for airbag according to claim 1, characterized in that, It also includes a spinning channel (11). The spinning channel (11) is located below the cooling air cylinder (10) and is connected to it.

12. The preparation device of the polyester industrial yarn for airbag according to claim 11, characterized in that, The length of the spinning channel (11) is 600 - 700 mm.

13. A preparation method of polyester industrial yarn for airbag, characterized in that, Adopt a preparation device for polyester industrial yarn for airbags as described in any one of claims 1 to 12.

14. The preparation method of a polyester industrial yarn for an airbag according to claim 13, characterized in that, The spinning process flow is: polyester melt is extruded through a spinneret plate → cooled in the slow cooling zone → cooled in the windless zone → cooled by the cooling air cylinder (10) → oiling → stretched by six pairs of hot rollers → shaped → texturized → wound; The spinning process parameters include: ambient temperature 35 - 40 °C; spinning temperature 291 - 310 °C; slow cooling zone temperature 290 - 320 °C; cooling air temperature 30 - 35 °C; cooling air speed 0.5 - 1.0 m / s; suction force of the suction duct ≤ 0.2 Pa; speed of the first pair of hot rollers 430 - 560 m / min, temperature 60 - 70 °C; speed of the second pair of hot rollers 450 - 580 m / min, temperature 90 - 100 °C; speed of the third pair of hot rollers 1850 - 2260 m / min, temperature 123 - 135 °C; speed of the fourth pair of hot rollers 2650 - 3600 m / min, temperature 210 - 250 °C; speed of the fifth pair of hot rollers 2580 - 3620 m / min, temperature 210 - 250 °C; speed of the sixth pair of hot rollers 2380 - 3420 m / min, temperature 180 - 220 °C; total draw ratio 5.52 - 6.38, main draw ratio 3.70 - 4.22, secondary draw ratio 1.39 - 1.71; winding speed 2550 - 3610 m / min; spinning tension 60 - 80 cN.

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