Preparation method for high-strength and low-elongation polyester industrial yarn

Abstract

A preparation method for a high-strength and low-elongation polyester industrial yarn (3), comprising the operation of winding the polyester industrial yarn (3) on a second pair of hot rollers. The second pair of hot rollers consist of a second hot roller a (1) and a second hot roller b (2). The rotating directions of the second hot roller a (1) and the second hot roller b (2) are opposite. The winding mode meets the following conditions: the surface of the polyester industrial yarn (3) in contact with the second hot roller b (2) is recorded as surface A, the surface of the polyester industrial yarn (3) in contact with the second hot roller a (1) is recorded as surface B, and the surface A and the surface B are opposite. According to the preparation method for the polyester industrial yarn (3), the tows are uniformly heated in a cross-winding mode, so that subsequent stretching is facilitated, and the prepared polyester industrial yarn has better performance and low costs.

Description

A method for preparing high-strength low-strength polyester industrial yarn Technical Field

[0001] The invention belongs to the technical field of polyester industrial yarns and relates to a method for preparing high-strength and low-elongation polyester industrial yarns. Background Art

[0002] Polyester industrial yarn, with its excellent mechanical properties such as high breaking strength, high elastic modulus, and good impact resistance, is widely used in ropes, tire cord, conveyor belts, geotextiles, and other fields. Customers demand not only high breaking strength but also strength at 2%, 4%, and 6% elongation under constant load. High-strength, low-elongation polyester industrial yarn, with its high strength, low elongation, high modulus, high dry heat shrinkage, and excellent deformation resistance, perfectly meets these customer requirements. It is primarily used in geotextiles, geogrids, and conveyor belts.

[0003] High-strength, low-elongation polyester industrial yarn has the characteristics of high strength, low elongation and high modulus. It is highly crystalline and highly oriented in the macromolecular chain structure. During the production process, high-multiple stretching and low-temperature heat setting are required to prevent the macromolecular chains from being deoriented.

[0004] However, there are two main problems in the existing technology. First, the polyester industrial yarn has a high density, a large number of monofilaments, and a large monofilament diameter. The uneven heating on the hot roller leads to uneven subsequent stretching, which is prone to problems such as lint and broken ends. Second, during the secondary high-multiple stretching, the temperature of the fourth pair of hot rollers is generally 210-250°C. After passing through the fourth pair of hot rollers, the polyester industrial yarn itself has a very high temperature. When it passes through the fifth pair of hot rollers for shaping, the temperature in the fifth hot box cannot be reduced by existing equipment. The high temperature of the yarn bundle is prone to deorientation of the macromolecular chains, resulting in a decrease in the molecular chain orientation and an increase in the elongation of the yarn bundle, which is not conducive to the production of high-strength and low-elongation industrial yarn.

[0005] The document "High performance PET fiber properties achieved at high speed using a combination of threadline modification and traditional post treatment. Polymer, Volume 38, Issue 5, 1997, Pages 1091-1100" shows that by adding a liquid bath during the spinning process, fibers with uniform fiber orientation and a high degree of molecular chain orientation can be obtained. Through subsequent low-multiple heat stretching and heat setting, high-strength and high-modulus PET industrial yarns can be obtained. Patent CN111304759B discloses a method for stretching polyester industrial yarns, proposing that wet heat stretching between a first pair of hot rollers and a second pair of hot rollers can produce polyester industrial yarns with uniform fiber structure and properties. The document "Research on the Production Process of High-Performance Polyester Industrial Yarns [J]. Synthetic Fibers, 2005(01):25-28." uses a stretching point locator to make the stretching process smoother and reduce damage to the fibers such as lint and broken ends caused by rapid stretching. However, adding a liquid bath and wet heat stretching will damage the oil film on the fiber surface, which is not conducive to subsequent stretching and the uniformity of oil content. Adding a stretching point locator requires spraying hot steam onto the surface of the tow, which is costly and will also damage the oil film on the surface of the tow.

[0006] Patent CN116043342A discloses a method for preparing polyester industrial yarn for geotextiles. The method uses two pairs of setting rollers to increase the setting time and crystallinity, and adds an air cooling device before the winder to prevent the core temperature of the yarn cake from exceeding the glass transition temperature and causing deorientation. This method is technically complex, and the addition of a pair of setting rollers increases costs. It also fails to consider the effects of orientation and crystallization on the unshaped yarn during the stretching process. Patent CN202688688U discloses a hot roller cooling system that adds a water circulation cooling device to the roller shaft drive device of the hot roller. This device has a high technical level and high cost, making it difficult to promote and use.

[0007] Therefore, it is of practical value to study a preparation method of high-strength low-elongation polyester industrial yarn that can solve the above technical problems.

[0008] Summary of the Invention

[0009] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing high-strength and low-elongation industrial yarn.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing high-strength, low-stretch polyester industrial yarn comprises winding the polyester industrial yarn around a second pair of heated rollers, wherein the second pair of heated rollers comprises a second heated roller a and a second heated roller b, and the second heated roller a and the second heated roller b rotate in opposite directions. The winding method satisfies the following conditions: a surface of the polyester industrial yarn in contact with the second heated roller b is designated as surface A, a surface of the polyester industrial yarn in contact with the second heated roller a is designated as surface B, and surface A and surface B are opposite surfaces.

[0012] In the prior art, the method of winding polyester industrial yarn around the second heated roller a and the second heated roller b is shown in Figure 1. The polyester industrial yarn 3 always contacts the second heated roller a1 and the second heated roller b2 on the same side surface. This has the following problems: the polyester industrial yarn has many monofilaments, and the yarn bundles are easily entangled. The monofilaments close to the heated roller surface are heated more, while the monofilaments far from the heated roller surface are heated less, resulting in uneven heating of the entire yarn bundle, which is not conducive to uniform stretching in the subsequent process.

[0013] The present invention changes the way polyester industrial yarn is wound on the second hot roller a and the second hot roller b in the prior art. As shown in Figure 2, the present invention adopts a cross-winding method. When the yarn bundle passes through the second hot roller b, one side of the yarn bundle is heated, and when it passes through the second hot roller a, the other side of the yarn bundle is heated. In this way, the yarn bundle can be heated evenly, which is beneficial to the subsequent stretching.

[0014] As the preferred technical solution:

[0015] According to the method for preparing high-strength, low-elongation polyester industrial yarn, the polyester industrial yarn is wound around the second hot roller a and the second hot roller b for more than one turn, the positions where the polyester industrial yarn is wound around the second hot roller a do not overlap, and the positions where the polyester industrial yarn is wound around the second hot roller b do not overlap.

[0016] In the method for preparing the high-strength, low-elongation polyester industrial yarn, the polyester industrial yarn is wound on the second pair of hot rollers in an "8" shape.

[0017] In the above-described method for preparing high-strength, low-stretch polyester industrial yarn, the second heated roller b and the second heated roller a are parallel to the front-to-back direction, the second heated roller b is located on the right side of the second heated roller a, and the polyester industrial yarn is fed from the right side, with surface A on top and surface B on the bottom during feeding; the winding process is as follows:

[0018] (1) The polyester industrial yarn passes under the second hot roller b and contacts it;

[0019] (2) The polyester industrial yarn passes over the second hot roller a and contacts it;

[0020] (3) The polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0021] (4) The polyester industrial yarn passes under the second hot roller a and contacts it;

[0022] (5) The polyester industrial yarn passes over the second hot roller b and contacts it;

[0023] (6) The polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0024] (7) The polyester industrial yarn passes under the second hot roller b and contacts it;

[0025] (8) Repeat steps (2) to (7) 5-6 times and then end;

[0026] Alternatively, the winding process is:

[0027] (1) The polyester industrial yarn passes over the second hot roller b and contacts it;

[0028] (2) The polyester industrial yarn passes under the second hot roller a and contacts it;

[0029] (3) The polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0030] (4) The polyester industrial yarn passes over the second hot roller a and contacts it;

[0031] (5) The polyester industrial yarn passes under the second hot roller b and contacts it;

[0032] (6) The polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0033] (7) The polyester industrial yarn passes over the second hot roller b and contacts it;

[0034] (8) Repeat steps (2) to (7) 5-6 times and then end.

[0035] In the method for preparing high-strength, low-elongation polyester industrial yarn as described above, the second hot roller a and the second hot roller b have the same temperature and speed, and the polyester industrial yarn is wound around the second hot roller a and the second hot roller b the same number of times. The more times the polyester industrial yarn is wound around the second pair of hot rollers, the better, so that the yarn bundle can be fully heated.

[0036] The above-mentioned method for preparing high-strength low-elongation polyester industrial yarn has the following overall process flow: polyester melt is extruded through a spinneret → slowly cooled → cooled in a windless zone → cooled by side-blown air → oiled → stretched and heat-set → networked → wound.

[0037] According to the method for preparing high-strength low-stretch polyester industrial yarn as described above, the stretching and heat setting adopts five pairs of hot rollers including the second pair of hot rollers; the speed of the first pair of hot rollers is 430-560 m / min and the temperature is 70-80°C; the speed of the second pair of hot rollers is 450-580 m / min and the temperature is 90-100°C; the speed of the third pair of hot rollers is 1850-2260 m / min and the temperature is 123-135°C; the speed of the fourth pair of hot rollers is 2650-3600 m / min and the temperature is 200-300°C. is 210-250℃; the speed of the fifth pair of hot rollers is 2580-3620m / min, and the temperature is 110-120℃; the winding speed is 2550-3610m / min; the total stretching ratio is 5.5-6.4, the main stretching ratio is 3.7-4.2, and the secondary stretching ratio is 1.0-2.0. The total stretching ratio = the speed of the fourth pair of hot rollers / the speed of the second pair of hot rollers, the main stretching ratio = the speed of the third pair of hot rollers / the speed of the second pair of hot rollers, and the secondary stretching ratio = the speed of the fourth pair of hot rollers / the speed of the third pair of hot rollers.

[0038] In the method for preparing high-strength, low-stretch polyester industrial yarn as described above, the fifth pair of hot rollers is located in the fifth heat box;

[0039] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air outlet, and the left and right panels are provided with a pressure-stabilizing porous plate (the pressure-stabilizing porous plate is similar to a shutter structure and can be rotated at a certain angle (0-90°) with the left and right side panels to fine-tune the pressure in the hot box). The suction port is connected to the suction device, and the cooling air outlet is connected to the cooling air outlet. Both the suction device and the cooling air outlet are in the activated state;

[0040] The temperature of the cooling air blown out by the cooling blowing device is 40-50°C.

[0041] In order to solve the problem that the temperature of the high-strength, low-elongation industrial yarn is high in the fifth hot box and it is easy to de-orient the yarn, the existing technology mainly solves it by not heating the fifth pair of hot rollers or adding a pair of cold rollers to increase the setting time; the present invention solves it by adjusting the structure of the hot box. Compared with the existing technology, on the one hand, it can further reduce the elongation of the industrial yarn and achieve improved product quality. On the other hand, the hot box of the present invention adopts a blowing and sucking method when making high-strength, low-elongation industrial yarn to cool the yarn bundle. When other varieties do not need cooling, the blowing, suction device and voltage-stabilizing porous plate can be turned off to restore the heat preservation function of the hot box.

[0042] In the above-mentioned method for preparing high-strength, low-elongation polyester industrial yarn, the intrinsic viscosity of the polyester melt is 1.10-1.15 dL / g, and the melting point is 260.0-260.5°C. The spinning process parameters are as follows:

[0043] Screw temperature: Zone 1 300-310°C, Zone 2 303-318°C, Zone 3 305-310°C, Zone 4 293-300°C, Zone 5 286-295°C, Zone 6 286-295°C, Zone 7 290-300°C;

[0044] Spinning temperature 291-306℃;

[0045] The side-blowing air temperature is 20±2℃, the side-blowing air humidity is 80±5%, and the side-blowing air speed is 0.7±0.1m / s;

[0046] The length of the slow cooling zone is 200-300mm, and the temperature of the slow cooling zone is 290±20℃;

[0047] The nozzle is oiled with Matsumoto crude oil, and the oiling rate is 0.8±0.3%;

[0048] The spinning tension is controlled at 300-400g;

[0049] To punch the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.25-0.35MPa and a compressed air temperature of 25-40℃.

[0050] The high-strength, low-elongation polyester industrial yarn has a linear density of 2170-2230 dtex, a breaking strength ≥8.50 cN / dtex, an elongation at break of 11-11.5%, a dry heat shrinkage of 11-12%, an elongation at a fixed load of 4.5-5.0%, and a hair degradation rate of 0.98-1.46%. Beneficial effects:

[0051] (1) The present invention provides a method for preparing high-strength, low-elongation polyester industrial yarn. The polyester industrial yarn is evenly heated on a second pair of hot rollers, which is beneficial to subsequent stretching, thereby obtaining low-crystallization, high-orientation, and evenly stretched fibers for preparing high-strength, low-elongation polyester industrial yarn.

[0052] (2) The present invention provides a method for preparing high-strength, low-elongation polyester industrial yarn. The polyester industrial yarn is stretched at a high ratio and shaped at a low temperature, which is beneficial to reducing the deorientation of the macromolecular chain and preparing a polyester industrial yarn with high strength, low elongation and low constant load elongation.

[0053] (3) By adjusting the structure of the hot box, the present invention can, on the one hand, further reduce the elongation of the polyester industrial yarn and improve the product quality. On the other hand, the hot box of the present invention can cool the polyester industrial yarn by blowing and sucking at the same time when making high-strength and low-elongation polyester industrial yarn, and can prevent the molecular structure of the yarn cake from changing during the winding process due to the temperature being higher than the glass transition temperature, thereby affecting the stability of the physical properties of the yarn cake. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG1 is a schematic diagram of polyester industrial yarn being wound on a second pair of hot rollers in the prior art;

[0055] FIG2 is a schematic diagram of the winding of polyester industrial yarn on a second pair of heated rollers in the present invention;

[0056] FIG3 is a front view of a fifth heat box of the present invention;

[0057] FIG4 is a side view of a fifth heat box of the present invention;

[0058] Among them, 1-second hot roller a, 2-second hot roller b, 3-polyester industrial yarn, 4-fifth pair of hot rollers a, 5-fifth pair of hot rollers b, 6-fifth heat box, 7-cooling air outlet, 8-suction device, 9-pressure stabilizing porous plate. DETAILED DESCRIPTION

[0059] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0060] The following are manufacturers and trade names of raw materials in the examples:

[0061] Polyester: Using purified terephthalic acid (PTA) and ethylene glycol (EG) as raw materials, antimony trioxide or ethylene glycol antimony as catalyst, three reactors connected in series undergo esterification, pre-polycondensation, and final polycondensation to produce polyethylene terephthalate (intrinsic viscosity of 0.64-0.70 dL / g), which is then pelletized to obtain polyester chips.

[0062] Solid-phase polymerization: Polyester chips with an intrinsic viscosity of 0.64-0.70 dL / g are heated to 200-240°C under nitrogen protection for solid-phase polymerization to increase the intrinsic viscosity of the polyester chips to 1.10-1.15 dL / g. After cooling, the chips are transported to the silo.

[0063] Process flow: slurry preparation (PTA+EG) → esterification → pre-polycondensation → final polycondensation → pelletizing → raw material storage tank → high-level silo → crystallization → preheater → reactor (solid phase polymerization) → cooler → storage → transportation → silo → screw.

[0064] Matsumoto crude oil: Matsumoto Oil & Fat Pharmaceutical Co., Ltd., brand HM-200.

[0065] The following is the test method of the performance in the embodiment:

[0066] Breaking strength: The polyester industrial yarn prepared in the examples was tested using the GB / T 16604-2017 standard;

[0067] Elongation at break: The polyester industrial yarn prepared in the examples was tested using the GB / T 16604-2017 standard;

[0068] Dry heat shrinkage: The polyester industrial yarn prepared in the examples was tested using the GB / T 16604-2017 standard;

[0069] Oil content: The test was conducted using the oil content test method for chemical fibers in GB / T 6504-2017, and the testing instrument was MQC+ from Oxford, UK.

[0070] Elongation under constant load: The polyester industrial yarn prepared in the examples was tested using the GB / T 16604-2017 standard;

[0071] Downgrade rate of wool yarn: The downgrade rate is determined according to the appearance requirements of polyester industrial yarn in GB / T 16604-2017. The number of downgraded yarn cakes with wool yarn and loop yarn and the number of full yarn cakes are counted over a period of time. The percentage of downgraded yarn cakes with wool yarn to the number of full yarn cakes is the downgrade rate of wool yarn.

[0072] Example 1

[0073] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0074] (1) Preparation of raw materials;

[0075] Polyester: intrinsic viscosity is 1.10 dL / g, melting point is 260.1°C;

[0076] Matsumoto crude oil;

[0077] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0078] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0079] Spinning process parameters:

[0080] The temperature of screw zone 1 is 300℃, zone 2 is 303℃, zone 3 is 305℃, zone 4 is 293℃, zone 5 is 286℃, zone 6 is 286℃, and zone 7 is 290℃;

[0081] Spinning temperature 296°C, side blowing temperature 18°C, side blowing humidity 80%, side blowing speed 0.6m / s, slow cooling zone length 200mm, slow cooling zone temperature 270°C;

[0082] The nozzle is oiled with Matsumoto crude oil at a rate of 0.5%.

[0083] The spinning tension was controlled at 300 g;

[0084] To punch the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.25 MPa and a compressed air temperature of 25°C;

[0085] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0086] As shown in FIG2 , the winding process of the polyester industrial yarn 3 on the second pair of hot rollers is as follows:

[0087] (1) The polyester industrial yarn passes under the second hot roller b2 and contacts it;

[0088] (II) the polyester industrial yarn passes over and contacts the second hot roller a1;

[0089] (III) the polyester industrial yarn passes through the left side of the second hot roller a1 and contacts it;

[0090] (IV) the polyester industrial yarn passes under the second hot roller a1 and contacts it;

[0091] (V) the polyester industrial yarn passes over and contacts the second hot roller b2;

[0092] (VI) the polyester industrial yarn passes through the right side of the second hot roller b2 and contacts it;

[0093] (VII) the polyester industrial yarn passes under the second hot roller b2 and contacts it;

[0094] (VIII) Repeating steps (II) to (VII) 5 times, and then ending; wherein the positions of the polyester industrial yarn wound on the second heated roller a1 and the second heated roller b2 do not overlap;

[0095] As shown in Figures 3 and 4, the fifth pair of hot rollers is located in the fifth heat box 6 and includes a fifth pair of hot rollers a and a fifth pair of hot rollers b;

[0096] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air blowing port, the left and right panels are provided with a pressure-stabilizing porous plate 9, the suction port is connected to the suction device 8, and the cooling air blowing port is connected to the cooling air blowing device 7. The suction device 8 and the cooling air blowing device 7 are both in the started state, and the temperature of the cooling air blown by the cooling air blowing device 7 is 40°C;

[0097] During the stretching and heat setting process, the speed of the first pair of hot rollers was 430 m / min and the temperature was 70°C; the speed of the second pair of hot rollers was 450 m / min and the temperature was 93°C; the speed of the third pair of hot rollers was 1850 m / min and the temperature was 131°C; the speed of the fourth pair of hot rollers was 2650 m / min and the temperature was 250°C; the speed of the fifth pair of hot rollers was 2580 m / min and the temperature was 110°C; the winding speed was 2550 m / min; the total stretching ratio was 5.89, the primary stretching ratio was 4.11, and the secondary stretching ratio was 1.43.

[0098] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2170 dtex, a breaking strength of 8.5 cN / dtex, an elongation at break of 11%, a dry heat shrinkage of 11%, an elongation at a fixed load of 4.7%, and a hair degradation rate of 1.07%.

[0099] Comparative Example 1

[0100] A method for preparing high-strength, low-stretch polyester industrial yarn is basically the same as that in Example 1, except that the winding process of the polyester industrial yarn on the second pair of hot rollers is as follows:

[0101] (1) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0102] (II) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0103] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0104] (IV) the polyester industrial yarn passes over and contacts the second hot roller a;

[0105] (V) the polyester industrial yarn passes over and contacts the second hot roller b;

[0106] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0107] (VII) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0108] (VIII) Repeat steps (II) to (VII) 5 times and then terminate.

[0109] The linear density of the high-strength, low-elongation polyester industrial yarn finally obtained is 2170 dtex, and the yarn degradation rate is 2.18%.

[0110] By comparing Comparative Example 1 with Example 1, it can be seen that since the winding process of Comparative Example 1 on the second pair of hot rollers is the winding method of the prior art, as shown in Figure 1, it will lead to an increase in the degradation rate of fuzz. This is because the number of polyester industrial yarn monofilaments is large and the yarn bundles are easily held together, so the monofilaments close to the surface of the hot roller are heated more, and the monofilaments far from the surface of the hot roller are heated less, resulting in uneven heating of the entire yarn bundle. Subsequently, at the same stretching multiple, the evenly heated monofilaments are fully stretched and oriented, and the unevenly heated monofilaments will be incompletely heated, resulting in the so-called "cold stretching" of the monofilaments, which will cause the monofilaments to be broken and produce fuzz.

[0111] Example 2

[0112] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0113] (1) Preparation of raw materials;

[0114] Polyester: intrinsic viscosity is 1.11 dL / g, melting point is 260°C;

[0115] Matsumoto crude oil;

[0116] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0117] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0118] Spinning process parameters:

[0119] The temperature of screw zone 1 is 300℃, zone 2 is 303℃, zone 3 is 305℃, zone 4 is 293℃, zone 5 is 286℃, zone 6 is 286℃, and zone 7 is 290℃;

[0120] Spinning temperature 292°C, side blowing temperature 18°C, side blowing humidity 75%, side blowing speed 0.6m / s, slow cooling zone length 250mm, slow cooling zone temperature 280°C;

[0121] The nozzle is oiled with Matsumoto crude oil at a rate of 0.6%.

[0122] The spinning tension was controlled at 322 g;

[0123] To punch the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.27 MPa and a compressed air temperature of 28°C;

[0124] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0125] The winding process of polyester industrial yarn on the second pair of hot rollers is as follows:

[0126] (1) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0127] (II) the polyester industrial yarn passes over and contacts the second hot roller a;

[0128] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0129] (IV) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0130] (V) the polyester industrial yarn passes over and contacts the second hot roller b;

[0131] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0132] (VII) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0133] (VIII) repeating steps (II) to (VII) 5 times and then ending; wherein the positions where the polyester industrial yarn is wound on the second heated roller a and the second heated roller b do not overlap;

[0134] The fifth pair of hot rollers is located in the fifth heat box;

[0135] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air outlet, and the left and right panels are provided with a pressure-stabilizing porous plate. The suction port is connected to the suction device, and the cooling air outlet is connected to the cooling air outlet. The suction device and the cooling air outlet are both in an activated state. The temperature of the cooling air blown by the cooling air outlet is 45°C.

[0136] During the stretching and heat setting process, the speed of the first pair of hot rollers was 440 m / min and the temperature was 72°C; the speed of the second pair of hot rollers was 460 m / min and the temperature was 90°C; the speed of the third pair of hot rollers was 1930 m / min and the temperature was 123°C; the speed of the fourth pair of hot rollers was 2800 m / min and the temperature was 220°C; the speed of the fifth pair of hot rollers was 2850 m / min and the temperature was 120°C; the winding speed was 2820 m / min; the total stretching ratio was 6.09, the primary stretching ratio was 4.2, and the secondary stretching ratio was 1.45.

[0137] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2180 dtex, a breaking strength of 8.6 cN / dtex, an elongation at break of 11%, a dry heat shrinkage of 11.2%, an elongation at a fixed load of 4.6%, and a hair degradation rate of 1.20%.

[0138] Example 3

[0139] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0140] (1) Preparation of raw materials;

[0141] Polyester: intrinsic viscosity is 1.12 dL / g, melting point is 260.2°C;

[0142] Matsumoto crude oil;

[0143] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0144] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0145] Spinning process parameters:

[0146] The temperature of screw zone 1 is 303°C, zone 2 is 307°C, zone 3 is 307°C, zone 4 is 295°C, zone 5 is 286°C, zone 6 is 286°C, and zone 7 is 290°C.

[0147] Spinning temperature 295°C, side blowing temperature 19°C, side blowing humidity 79%, side blowing speed 0.7m / s, slow cooling zone length 250mm, slow cooling zone temperature 290°C;

[0148] The nozzle is oiled with Matsumoto crude oil at a rate of 0.7%.

[0149] The spinning tension was controlled at 334 g;

[0150] To drill the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.3MPa and a compressed air temperature of 32℃;

[0151] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0152] The winding process of polyester industrial yarn on the second pair of hot rollers is as follows:

[0153] (1) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0154] (II) the polyester industrial yarn passes over and contacts the second hot roller a;

[0155] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0156] (IV) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0157] (V) the polyester industrial yarn passes over and contacts the second hot roller b;

[0158] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0159] (VII) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0160] (VIII) repeating steps (II) to (VII) 5 times and then ending; wherein the positions where the polyester industrial yarn is wound on the second heated roller a and the second heated roller b do not overlap;

[0161] The fifth pair of hot rollers is located in the fifth heat box;

[0162] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air outlet, and the left and right panels are provided with a pressure-stabilizing porous plate. The suction port is connected to the suction device, and the cooling air outlet is connected to the cooling air outlet. The suction device and the cooling air outlet are both in an activated state. The temperature of the cooling air blown by the cooling air outlet is 45°C.

[0163] During the stretching and heat setting process, the speed of the first pair of hot rollers is 480 m / min and the temperature is 74°C; the speed of the second pair of hot rollers is 500 m / min and the temperature is 92°C; the speed of the third pair of hot rollers is 2000 m / min and the temperature is 125°C; the speed of the fourth pair of hot rollers is 3000 m / min and the temperature is 230°C; the speed of the fifth pair of hot rollers is 3020 m / min and the temperature is 112°C; the winding speed is 3010 m / min; the total stretching ratio is 6, the primary stretching ratio is 4, and the secondary stretching ratio is 1.5.

[0164] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2190 dtex, a breaking strength of 8.6 cN / dtex, an elongation at break of 11.2%, a dry heat shrinkage of 11.4%, an elongation at a fixed load of 4.8%, and a hair degradation rate of 1.13%.

[0165] Example 4

[0166] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0167] (1) Preparation of raw materials;

[0168] Polyester: intrinsic viscosity is 1.13 dL / g, melting point is 260.3°C;

[0169] Matsumoto crude oil;

[0170] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0171] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0172] Spinning process parameters:

[0173] The temperature of screw zone 1 is 305℃, zone 2 is 310℃, zone 3 is 310℃, zone 4 is 298℃, zone 5 is 286℃, zone 6 is 286℃, and zone 7 is 290℃;

[0174] Spinning temperature 291°C, side blowing temperature 20°C, side blowing humidity 80%, side blowing speed 0.7m / s, slow cooling zone length 200mm, slow cooling zone temperature 300°C;

[0175] The nozzle is oiled with Matsumoto crude oil at a rate of 0.8%.

[0176] The spinning tension was controlled at 356 g;

[0177] To punch the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.32MPa and a compressed air temperature of 35℃;

[0178] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0179] The winding process of polyester industrial yarn on the second pair of hot rollers is as follows:

[0180] (1) the polyester industrial yarn passes over the second hot roller b and contacts the second hot roller b;

[0181] (II) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0182] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0183] (IV) the polyester industrial yarn passes over and contacts the second hot roller a;

[0184] (V) the polyester industrial yarn passes under the second hot roller b and contacts it;

[0185] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0186] (VII) the polyester industrial yarn passes over and contacts the second hot roller b;

[0187] (VIII) repeating steps (II) to (VII) 5 times and then ending; wherein the positions where the polyester industrial yarn is wound on the second heated roller a and the second heated roller b do not overlap;

[0188] The fifth pair of hot rollers is located in the fifth heat box;

[0189] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air outlet, and the left and right panels are provided with a pressure-stabilizing porous plate. The suction port is connected to the suction device, and the cooling air outlet is connected to the cooling air outlet. The suction device and the cooling air outlet are both in the activated state. The temperature of the cooling air blown by the cooling air outlet is 48°C.

[0190] During the stretching and heat setting process, the speed of the first pair of hot rollers was 500 m / min and the temperature was 76°C; the speed of the second pair of hot rollers was 520 m / min and the temperature was 94°C; the speed of the third pair of hot rollers was 1950 m / min and the temperature was 130°C; the speed of the fourth pair of hot rollers was 3000 m / min and the temperature was 240°C; the speed of the fifth pair of hot rollers was 3050 m / min and the temperature was 115°C; the winding speed was 3030 m / min; the total stretching ratio was 5.77, the primary stretching ratio was 3.75, and the secondary stretching ratio was 1.54.

[0191] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2200 dtex, a breaking strength of 8.5 cN / dtex, an elongation at break of 11.4%, a dry heat shrinkage of 11.6%, an elongation at a fixed load of 5%, and a hair degradation rate of 1.03%.

[0192] Example 5

[0193] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0194] (1) Preparation of raw materials;

[0195] Polyester: intrinsic viscosity is 1.14 dL / g, melting point is 260.4°C;

[0196] Matsumoto crude oil;

[0197] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0198] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0199] Spinning process parameters:

[0200] The temperature of screw zone 1 is 307°C, zone 2 is 311°C, zone 3 is 308°C, zone 4 is 304°C, zone 5 is 291°C, zone 6 is 291°C, and zone 7 is 292°C;

[0201] Spinning temperature 291°C, side blowing temperature 20°C, side blowing humidity 83%, side blowing speed 0.8m / s, slow cooling zone length 200mm, slow cooling zone temperature 310°C;

[0202] The nozzle is oiled with Matsumoto crude oil at a rate of 0.9%.

[0203] The spinning tension was controlled at 377 g;

[0204] To punch the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.34MPa and a compressed air temperature of 38℃;

[0205] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0206] The winding process of polyester industrial yarn on the second pair of hot rollers is as follows:

[0207] (1) the polyester industrial yarn passes over the second hot roller b and contacts the second hot roller b;

[0208] (II) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0209] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0210] (IV) the polyester industrial yarn passes over and contacts the second hot roller a;

[0211] (V) the polyester industrial yarn passes under the second hot roller b and contacts it;

[0212] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0213] (VII) the polyester industrial yarn passes over and contacts the second hot roller b;

[0214] (VIII) repeating steps (II) to (VII) 5 times and then ending; wherein the positions where the polyester industrial yarn is wound on the second heated roller a and the second heated roller b do not overlap;

[0215] The fifth pair of hot rollers is located in the fifth heat box;

[0216] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air outlet, and the left and right panels are provided with a pressure-stabilizing porous plate. The suction port is connected to the suction device, and the cooling air outlet is connected to the cooling air outlet. The suction device and the cooling air outlet are both in the activated state. The temperature of the cooling air blown by the cooling air outlet is 48°C.

[0217] During the stretching and heat setting process, the speed of the first pair of hot rollers was 540 m / min and the temperature was 78°C; the speed of the second pair of hot rollers was 560 m / min and the temperature was 96°C; the speed of the third pair of hot rollers was 2105 m / min and the temperature was 132°C; the speed of the fourth pair of hot rollers was 3400 m / min and the temperature was 210°C; the speed of the fifth pair of hot rollers was 3450 m / min and the temperature was 116°C; the winding speed was 3430 m / min; the total stretching ratio was 6.07, the primary stretching ratio was 3.76, and the secondary stretching ratio was 1.62.

[0218] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2210 dtex, a breaking strength of 8.6 cN / dtex, an elongation at break of 11.5%, a dry heat shrinkage of 11.8%, an elongation at a fixed load of 4.7%, and a hair degradation rate of 1.35%.

[0219] Example 6

[0220] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0221] (1) Preparation of raw materials;

[0222] Polyester: intrinsic viscosity is 1.15 dL / g, melting point is 260.5°C;

[0223] Matsumoto crude oil;

[0224] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0225] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0226] Spinning process parameters:

[0227] The temperature of screw zone 1 is 310℃, zone 2 is 318℃, zone 3 is 306℃, zone 4 is 300℃, zone 5 is 295℃, zone 6 is 295℃, and zone 7 is 300℃;

[0228] Spinning temperature: 306°C, side blowing temperature: 21°C, side blowing humidity: 85%, side blowing speed: 0.7m / s, slow cooling zone length: 300mm, slow cooling zone temperature: 300°C;

[0229] The nozzle is oiled with Matsumoto crude oil at a rate of 0.8%.

[0230] The spinning tension was controlled at 395 g;

[0231] To punch the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.28MPa and a compressed air temperature of 40℃;

[0232] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0233] The winding process of polyester industrial yarn on the second pair of hot rollers is as follows:

[0234] (1) the polyester industrial yarn passes over the second hot roller b and contacts the second hot roller b;

[0235] (II) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0236] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0237] (IV) the polyester industrial yarn passes over and contacts the second hot roller a;

[0238] (V) the polyester industrial yarn passes under the second hot roller b and contacts it;

[0239] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0240] (VII) the polyester industrial yarn passes over and contacts the second hot roller b;

[0241] (VIII) repeating steps (II) to (VII) 5 times and then ending; wherein the positions where the polyester industrial yarn is wound on the second heated roller a and the second heated roller b do not overlap;

[0242] The fifth pair of hot rollers is located in the fifth heat box;

[0243] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air blowing port, the left and right panels are provided with a pressure-stabilizing porous plate, the suction port is connected to the suction device, the cooling air blowing port is connected to the cooling air blowing device, the suction device and the cooling air blowing device are both in an activated state, and the temperature of the cooling air blown by the cooling air blowing device is 50°C;

[0244] During the stretching and heat setting process, the speed of the first pair of hot rollers was 560 m / min and the temperature was 80°C; the speed of the second pair of hot rollers was 580 m / min and the temperature was 98°C; the speed of the third pair of hot rollers was 2180 m / min and the temperature was 135°C; the speed of the fourth pair of hot rollers was 3500 m / min and the temperature was 240°C; the speed of the fifth pair of hot rollers was 3510 m / min and the temperature was 118°C; the winding speed was 3500 m / min; the total stretching ratio was 6.03, the primary stretching ratio was 3.76, and the secondary stretching ratio was 1.61.

[0245] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2220 dtex, a breaking strength of 8.6 cN / dtex, an elongation at break of 11.4%, a dry heat shrinkage of 12%, an elongation at a fixed load of 4.6%, and a hair degradation rate of 1.30%.

[0246] Example 7

[0247] A method for preparing high-strength, low-strength polyester industrial yarn comprises the following steps:

[0248] (1) Preparation of raw materials;

[0249] Polyester: intrinsic viscosity is 1.15 dL / g, melting point is 260.3°C;

[0250] Matsumoto crude oil;

[0251] (2) Preparation of high-strength, low-stretch polyester industrial yarn;

[0252] The overall process flow is as follows: polyester melt is extruded through the spinneret → slow cooling → cooling in a windless zone → cooling with side air blowing → oiling → stretching and heat setting → web forming → winding;

[0253] Spinning process parameters:

[0254] The temperature of screw zone 1 is 310℃, zone 2 is 318℃, zone 3 is 306℃, zone 4 is 300℃, zone 5 is 295℃, zone 6 is 295℃, and zone 7 is 300℃;

[0255] Spinning temperature 306°C, side blowing temperature 22°C, side blowing humidity 83%, side blowing speed 0.7m / s, slow cooling zone length 250mm, slow cooling zone temperature 305°C;

[0256] The nozzle is oiled with Matsumoto crude oil at a rate of 1.1%.

[0257] The spinning tension is controlled at 400g;

[0258] To drill the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.35MPa and a compressed air temperature of 36°C;

[0259] Among them, five pairs of hot rollers are used for stretching and heat setting;

[0260] The winding process of polyester industrial yarn on the second pair of hot rollers is as follows:

[0261] (1) the polyester industrial yarn passes over the second hot roller b and contacts the second hot roller b;

[0262] (II) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0263] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0264] (IV) the polyester industrial yarn passes over and contacts the second hot roller a;

[0265] (V) the polyester industrial yarn passes under the second hot roller b and contacts it;

[0266] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0267] (VII) the polyester industrial yarn passes over and contacts the second hot roller b;

[0268] (VIII) repeating steps (II) to (VII) 5 times and then ending; wherein the positions where the polyester industrial yarn is wound on the second heated roller a and the second heated roller b do not overlap;

[0269] The fifth pair of hot rollers is located in the fifth heat box;

[0270] The fifth hot box includes a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air blowing port, the left and right panels are provided with a pressure-stabilizing porous plate, the suction port is connected to the suction device, the cooling air blowing port is connected to the cooling air blowing device, the suction device and the cooling air blowing device are both in an activated state, and the temperature of the cooling air blown by the cooling air blowing device is 50°C;

[0271] During the stretching and heat setting process, the speed of the first pair of hot rollers was 550 m / min and the temperature was 76°C; the speed of the second pair of hot rollers was 570 m / min and the temperature was 100°C; the speed of the third pair of hot rollers was 2260 m / min and the temperature was 135°C; the speed of the fourth pair of hot rollers was 3600 m / min and the temperature was 250°C; the speed of the fifth pair of hot rollers was 3620 m / min and the temperature was 120°C; the winding speed was 3610 m / min; the total stretching ratio was 6.32, the primary stretching ratio was 3.96, and the secondary stretching ratio was 1.59.

[0272] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2230 dtex, a breaking strength of 8.7 cN / dtex, an elongation at break of 11.3%, a dry heat shrinkage of 12%, an elongation at a fixed load of 4.5%, and a hair degradation rate of 1.46%.

[0273] Example 8

[0274] A method for preparing high-strength, low-stretch polyester industrial yarn is basically the same as that in Example 1, except that the winding process of the polyester industrial yarn on the second pair of hot rollers is as follows:

[0275] (1) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0276] (II) the polyester industrial yarn passes over and contacts the second hot roller a;

[0277] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0278] (IV) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0279] (V) the polyester industrial yarn passes over and contacts the second hot roller b;

[0280] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0281] (VII) the polyester industrial yarn passes under the second hot roller b and contacts the second hot roller b;

[0282] (VIII) Repeat steps (II) to (VII) 6 times and then terminate.

[0283] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2170 dtex, a breaking strength of 8.52 cN / dtex, an elongation at break of 11.1%, a dry heat shrinkage of 11%, an elongation at a fixed load of 4.7%, and a hair degradation rate of 0.98%.

[0284] Example 9

[0285] A method for preparing high-strength, low-stretch polyester industrial yarn is basically the same as that in Example 1, except that the winding process of the polyester industrial yarn on the second pair of hot rollers is as follows:

[0286] (1) the polyester industrial yarn passes over the second hot roller b and contacts the second hot roller b;

[0287] (II) the polyester industrial yarn passes under the second hot roller a and contacts the second hot roller a;

[0288] (III) the polyester industrial yarn passes through the left side of the second hot roller a and contacts it;

[0289] (IV) the polyester industrial yarn passes over and contacts the second hot roller a;

[0290] (V) the polyester industrial yarn passes under the second hot roller b and contacts it;

[0291] (VI) the polyester industrial yarn passes through the right side of the second hot roller b and contacts it;

[0292] (VII) The polyester industrial yarn passes over the second hot roller b and contacts it

[0293] (VIII) Repeat steps (II) to (VII) 6 times and then terminate.

[0294] The final high-strength, low-elongation polyester industrial yarn has a linear density of 2170 dtex, a breaking strength of 8.52 cN / dtex, an elongation at break of 11%, a dry heat shrinkage of 11%, an elongation at a fixed load of 4.7%, and a hair degradation rate of 1.02%.

Claims

1. A method for preparing high-strength low-stretch polyester industrial yarn, comprising winding the polyester industrial yarn on a second pair of hot rollers, the second pair of hot rollers consisting of a second hot roller a and a second hot roller b, characterized in that: The second hot roller a and the second hot roller b rotate in opposite directions, and the winding method satisfies: the surface of the polyester industrial yarn in contact with the second hot roller b is recorded as surface A, the surface of the polyester industrial yarn in contact with the second hot roller a is recorded as surface B, and surface A and surface B are opposite surfaces. The polyester industrial yarn is wound around the second hot roller a and the second hot roller b for more than one turn, and the positions where the polyester industrial yarn is wound around the second hot roller a do not overlap, and the positions where the polyester industrial yarn is wound around the second hot roller b do not overlap; The polyester industrial yarn is wound around the second pair of hot rollers in a figure-8 pattern; The second hot roller b and the second hot roller a are parallel to the front-to-back direction. The second hot roller b is located on the right side of the second hot roller a. The polyester industrial yarn is fed from the right side, and when feeding, surface A is on the top and surface B is on the bottom. The winding process is: (1) The polyester industrial yarn passes under the second hot roller b and contacts it; (2) The polyester industrial yarn passes over the second hot roller a and contacts it; (3) The polyester industrial yarn passes through the left side of the second hot roller a and contacts it; (4) The polyester industrial yarn passes under the second hot roller a and contacts it; (5) The polyester industrial yarn passes over the second hot roller b and contacts it; (6) The polyester industrial yarn passes through the right side of the second hot roller b and contacts it; (7) The polyester industrial yarn passes under the second hot roller b and contacts it; (8) Repeat steps (2) to (7) 5-6 times and then end; Alternatively, the winding process is: (1) The polyester industrial yarn passes over the second hot roller b and contacts it; (2) The polyester industrial yarn passes under the second hot roller a and contacts it; (3) The polyester industrial yarn passes through the left side of the second hot roller a and contacts it; (4) The polyester industrial yarn passes over the second hot roller a and contacts it; (5) The polyester industrial yarn passes under the second hot roller b and contacts it; (6) The polyester industrial yarn passes through the right side of the second hot roller b and contacts it; (7) The polyester industrial yarn passes over the second hot roller b and contacts it; (8) Repeat steps (2) to (7) 5-6 times and then end; The linear density of high-strength low-stretch polyester industrial yarn is 2170-2230dtex.

2. The method for preparing high-strength low-strength polyester industrial yarn according to claim 1, characterized in that: The second hot roller a and the second hot roller b have the same temperature and speed, and the number of turns of the polyester industrial yarn wound around the second hot roller a and the second hot roller b is the same.

3. The method for preparing high-strength low-strength polyester industrial yarn according to claim 1, characterized in that: The overall process flow is: polyester melt is extruded through the spinneret → slow cooling → cooling in the windless zone → side-blowing cooling → oiling → stretching and heat setting → networking → winding.

4. The method for preparing high-strength low-strength polyester industrial yarn according to claim 3, characterized in that: The stretching heat setting adopts five pairs of hot rollers including the second pair of hot rollers; the speed of the first pair of hot rollers is 430-560m / min, and the temperature is 70-80℃; the speed of the second pair of hot rollers is 450-580m / min, and the temperature is 90-100℃; the speed of the third pair of hot rollers is 1850-2260m / min, and the temperature is 123-135℃; the speed of the fourth pair of hot rollers is 2650-3600m / min, and the temperature is 210-250℃; the speed of the fifth pair of hot rollers is 2580-3620m / min, and the temperature is 110-120℃; the winding speed is 2550-3610m / min; the total stretching multiple is 5.5-6.4, the main stretching multiple is 3.7-4.2, and the secondary stretching multiple is 1.0-2.

0.

5. The method for preparing high-strength and low-stretch polyester industrial yarn according to claim 4, characterized in that: The fifth pair of hot rollers is located in the fifth heat box; The fifth heat box comprises a rear side panel, a left side panel, a right side panel, a top panel, and a front side door. The rear side panel is provided with a suction port, the top panel is provided with a cooling air blowing port, the left side panel and the right side panel are provided with a pressure-stabilizing porous plate (9), the suction port is connected to a suction device (8), the cooling air blowing port is connected to a cooling air blowing device (7), and the suction device (8) and the cooling air blowing device (7) are both in an activated state; The temperature of the cooling air blown out by the cooling air blowing device (7) is 40-50°C.

6. The method for preparing high-strength low-strength polyester industrial yarn according to claim 3, characterized in that: The intrinsic viscosity of the polyester melt is 1.10-1.15 dL / g, and the melting point is 260.0-260.5°C; the spinning process parameters are as follows: Screw temperature: Zone 1 300-310°C, Zone 2 303-318°C, Zone 3 305-310°C, Zone 4 293-300°C, Zone 5 286-295°C, Zone 6 286-295°C, Zone 7 290-300°C; Spinning temperature 291-306℃; The side-blowing temperature is 20±2℃, the side-blowing humidity is 80±5%, and the side-blowing speed is 0.7±0.1m / s; The length of the slow cooling zone is 200-300mm, and the temperature of the slow cooling zone is 290±20℃; The nozzle is oiled with Matsumoto crude oil, and the oiling rate is 0.8±0.3%; The spinning tension is controlled at 300-400g; To drill the network node, a network device of model SPS-35-48Y is used, with a network pressure of 0.25-0.35MPa and a compressed air temperature of 25-40℃.

7. The method for preparing high-strength low-strength polyester industrial yarn according to claim 1, characterized in that: The breaking strength of high-strength, low-elongation polyester industrial yarn is ≥8.50cN / dtex, the breaking elongation is 11-11.5%, the dry heat shrinkage is 11-12%, the fixed load elongation is 4.5-5.0%, and the hair yarn degradation rate is 0.98-1.46%.

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