CN109735936B

CN109735936B - Preparation method of polyester industrial yarn for heavy-duty hoisting belt

Info

Publication number: CN109735936B
Application number: CN201811614105.0A
Authority: CN
Inventors: 范红卫; 王山水; 汤方明
Original assignee: Jiangsu Hengli Chemical Fiber Co Ltd
Current assignee: Jiangsu Hengli Chemical Fiber Co Ltd
Priority date: 2018-12-27
Filing date: 2018-12-27
Publication date: 2020-07-07
Anticipated expiration: 2038-12-27
Also published as: CN109735936A

Abstract

The invention relates to a preparation method of polyester industrial yarn for a heavy-duty hoisting belt, which comprises the following steps: performing solid phase polycondensation tackifying, melting, metering, extruding, cooling, oiling, plying, stretching, twisting, heat setting, relaxation heat treatment and winding on the polyester melt to obtain the polyester industrial yarn for the heavy-duty hoisting belt; the preparation method of the polyester before solid phase polycondensation tackifying comprises the following steps: modifying terephthalic acid, ethylene glycol and doped Sb₂O₃Uniformly mixing the powder, and then carrying out esterification reaction and polycondensation reaction in sequence; the relaxation heat treatment is to pass the polyester filament bundle through a space of 200-240 ℃ in a state that the overfeed rate of the winding is 3.0-5.0%. The invention improves the integrity of fiber crystallization, reduces the thermal shrinkage in the application process and simultaneously reduces the addition amount of antimony catalysts by the mutual matching of the heat treatment temperature and the higher overfeed rate, and has simple process, low cost and good application prospect.

Description

Preparation method of polyester industrial yarn for heavy-duty hoisting belt

Technical Field

The invention belongs to the technical field of polyester fibers, and relates to a preparation method of polyester industrial yarns for heavy-duty hoisting belts.

Background

The steel wire rope is a traditional hoisting tool, and is easy to damage and destroy articles to a certain extent, and the hoisting belt has been produced since the 50 th century, gradually replaces the steel wire rope, and is widely applied to the fields of ships, ports, metallurgy, steel, machinery, construction sites, mines, petroleum, chemical industry, hydropower stations, ports, wharfs, electric power, electronics, warehouses, transportation, military affairs and the like.

Because the hoisting belt needs to be capable of bearing larger pulling force and the operation environment is worse, certain requirements are provided for the material of the hoisting belt. The polyester industrial yarn has the advantages of high modulus, low elongation, good heat resistance, strong acid resistance, fatigue resistance and the like, and becomes a common material for hoisting belts. The hoisting belt made of the polyester industrial yarn has the following characteristics besides the advantages: 1) the texture is soft, so the use of the hoisting belt can reduce the damage to the surface which is easy to operate and particularly reduce the damage to the painted surface; 2) the weight of the hoisting belt is 25 percent of that of a metal hoisting rigging with the same tension, so that the hoisting belt is easy to carry, transport and store and is very easy to operate; 3) the safety and reliability are realized, the tensile property of the hoisting belt is close to that of a steel wire rope, and the safety coefficient is high.

However, the heavy hoisting belt is large in load bearing and easy to heat after long-time operation, the polyester industrial yarn can undergo irreversible heat shrinkage after being heated, and the shrinkage is more obvious after repeated times. If the heavy hoisting belt is in the state for a long time, the heavy hoisting belt is easy to break, and the use safety is influenced. Therefore, the requirement of the polyester industrial yarn of the heavy hoisting belt on the thermal shrinkage rate is higher, but the thermal shrinkage rate of the polyester industrial yarn is higher at present, so that the requirement of the heavy hoisting belt is difficult to meet.

In addition, the synthesis methods used in the production of PET polyester materials at present are mainly classified into ester exchange method (DMT method) and direct condensation method (PTA method), and the catalyst used in the polyester synthesis process is mainly antimony catalyst in the market. With the continuous development of society, the requirements of people on environmental protection are gradually increased, and environmental protection production is a necessary trend of modern industrial production. The metal antimony is harmful to human bodies and brings harm to people and nature, and the environmental protection problem of the PET material containing metal such as antimony has attracted people's attention at present, but compared with other catalysts, antimony trioxide and other antimony catalysts have the advantages of intermediate activity, low price, low promotion to side reaction and the like, so that currently, antimony catalysts are still widely applied in the market, the market use proportion of the antimony catalysts reaches 90%, and the antimony catalysts are difficult to be comprehensively replaced by other catalysts. The common antimony-based catalyst such as Sb is available on the market₂O₃The addition amount in the polyester synthesis process is large, the influence of the large addition amount of the antimony catalyst on the environment is also large, the environment-friendly production of polyester is not facilitated, and the antimony catalyst with the small addition amount cannot catalyze the reaction of all raw materials participating in the polyester synthesis, so that the requirement of polyester production cannot be met.

Therefore, the development of the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, which has small thermal shrinkage and small addition amount of the antimony catalyst, has practical significance.

Disclosure of Invention

The invention aims to overcome the defects of large heat shrinkage rate and large using amount of antimony catalysts in the prior art, and provides a preparation method of polyester industrial yarns for heavy-duty hoisting belts, which has small heat shrinkage rate and small adding amount of antimony catalysts.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt comprises the following steps of carrying out solid-phase polycondensation tackifying, melting, metering, extruding, cooling, oiling, plying, stretching, twisting, heat setting, relaxation heat treatment and winding on a polyester melt to prepare the polyester industrial yarn for the heavy-duty hoisting belt;

the preparation method of the polyester before solid-phase polycondensation tackifying comprises the following steps: modifying terephthalic acid, ethylene glycol and doped Sb₂O₃Uniformly mixing the powder, and then carrying out esterification reaction and polycondensation reaction in sequence;

Sb₂O₃the doping modification process comprises the following steps: firstly, containing metal ions M^x+With Sb-containing solution³⁺Uniformly mixing the solution, then dropwise adding a precipitator until the pH value of the mixed solution is 9-10, and finally calcining and crushing a precipitation product; metal ion M^x+Is Mg²⁺、Ca²⁺、Ba²⁺And Zn²⁺One or more of (1);

the relaxation heat treatment refers to that the polyester tows pass through a space with a certain temperature in a proper relaxation state;

the proper relaxation state means that the overfeed rate of winding is 3.0-5.0%;

the certain temperature is 200-240 ℃.

The shrinkage rate of the polyester industrial yarn is reduced by the mutual matching of the heat treatment temperature and the overfeed rate, when the fiber is subjected to heat treatment, macromolecular chains in an amorphous area of the fiber are easy to form folding chains, the further growth of crystal grains is facilitated, the crystallinity is increased at the moment, and the fiber can shrink a certain amount along with the increase of the crystallinity.

The invention also provides a method for preparing the metal ion M^x+With Sb-containing solution³⁺The solution is mixed uniformly, precipitated and calcined, so that the doping and blending of metal oxide with certain catalytic activity and antimony trioxide are realized, the metal oxide is more than one of MgO, CaO, BaO and ZnO, and after the metal oxide is doped with the antimony trioxide, the metal oxide enters the lattice site of the antimony by inhibiting the crystallization of the antimony trioxide, the growth of cubic antimony trioxide crystal grains and isomorphous substitution of the antimony, so that the antimony trioxide crystal generates defects, the crystal form generates change, the crystal grain size is reduced, and the specific surface area S of the antimony trioxide catalyst is improved_gMeanwhile, the metal is also enriched on the surface of part of the antimony trioxide crystal, so that the activity r on the unit surface area of the antimony trioxide_sIncrease of specific surface area S_gAnd activity per unit surface area r_sThe larger the catalyst, the higher the catalytic activity of the catalyst, enabling the invention to be used with low Sb₂O₃The catalytic synthesis of polyester is realized under the addition amount, which is beneficial to the environmental protection production.

As a preferred technical scheme:

according to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the single-filament fineness of the polyester industrial yarn for the heavy-duty hoisting belt is 8.0-9.0 dtex, the breaking strength is not less than 8.2N, the linear density is 3300-4400 dtex, the linear density deviation rate is +/-2.0%, and the breaking elongation rate is 6.5-9.5%.

The preparation method of the polyester industrial yarn for the heavy-duty hoisting belt comprises the step of preparing the polyester industrial yarn containing the metal ions M^x+The concentration of the solution (C) is 0.5-10 mol%, water as solvent, NO as anion in solution₃ ^-(ii) a The Sb-containing compound³⁺The solution of (a) is Sb with the concentration of 5-10 mol%₂O₃The solvent of (1) is oxalic acid; the precipitator is ammonia water with the concentration of 2 mol/L; at the beginning of the precipitation, the metal ions M in the mixed solution^x+And Sb³⁺In a molar ratio of 1-3: 100, Sb₂O₃Is the polyester catalyst with highest cost performance at present, and is prepared by permeating metal oxide (namely M)₂O_X) Inhibiting antimony trioxide (Sb)₂O₃) Crystallization of (b) and growth of cubic antimony trioxide grains, with metal ion M^x+Can replace antimony to enter the lattice site of antimony, so that the antimony trioxide crystal generates defects to improve the catalytic activity of antimony trioxide. If the amount of the doped metal oxide is too small (the molar ratio is too low), the influence on the crystal grains of the antimony trioxide is low, and if the amount of the doped metal oxide is too large (the molar ratio is too high), the Sb in the main body of the catalyst is enabled to be too much³⁺The large reduction range is not favorable for improving the catalytic activity of the antimony trioxide;

washing and drying the precipitate product before calcining, wherein the drying temperature is 105-110 ℃, and the drying time is 2-3 h; the calcining process comprises the following steps: firstly, heating to 400 ℃, then preserving heat for 2-3 h, then heating to 900 ℃, preserving heat for 1-2 h, and finally cooling in the air;

Sb₂O₃after doping modification, crushing to obtain powder with average grain size less than 0.5 micron.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the preparation steps of the polyester before solid-phase polycondensation and tackifying are as follows:

(1) performing esterification reaction;

preparing slurry from terephthalic acid and ethylene glycol, and adding doped modified Sb₂O₃Uniformly mixing the powder, the flatting agent and the stabilizing agent, and pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is normal pressure to 0.3MPa, the esterification reaction temperature is 250-260 ℃, and the esterification reaction endpoint is determined when the distilled amount of water in the esterification reaction reaches more than 90% of a theoretical value;

(2) performing polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the condition of negative pressure, wherein the pressure in the stage is stably pumped from normal pressure to below 500Pa in 30-50 min, the reaction temperature is 250-260 ℃, the reaction time is 30-50 min, then continuously pumping vacuum to perform the polycondensation reaction in a high vacuum stage, so that the reaction pressure is further reduced to below 100Pa, the reaction temperature is 270-282 ℃, and the reaction time is 50-90 min.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the molar ratio of the terephthalic acid to the ethylene glycol is 1: 1.2-2.0, and the doped and modified Sb is₂O₃The addition amounts of the powder, the delustering agent and the stabilizer are respectively 0.012-0.015 wt%, 0.20-0.25 wt% and 0.01-0.05 wt% of the addition amount of the terephthalic acid. Sb in polyester synthesis process in prior art₂O₃The amount of (A) is usually 0.02 to 0.04 wt% of the amount of terephthalic acid, and the amount of antimony-based catalyst is high, mainly due to undoped Sb₂O₃Activity per unit surface area r_sLow and specific surface area S_gSmall, therefore Sb₂O₃The overall catalytic activity is lower, and the invention is realized by the p-Sb₂O₃Doping modification is carried out to improve Sb₂O₃Thus significantly reducing Sb in the polyester synthesis process₂O₃The amount of (c) added.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the flatting agent is titanium dioxide, and the stabilizing agent is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the intrinsic viscosity of the polyester after solid-phase polycondensation and tackifying is 1.0-1.2 dL/g.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the space with a certain temperature is a space between a pair of hot plates which are arranged in parallel and are not coplanar, and the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment; the length of the two hot plates is 3.0-4.0 m along the running direction of the polyester tows, and the two ends of the two hot plates are flush; when the polyester tows pass through the middle of the two hot plates, the distance between the polyester tows and the two hot plates is 5-10 mm. The heat treatment method has the advantages that the energy can be obtained through macromolecular rearrangement by controlling the temperature of the hot plate (namely the certain temperature), the length of the hot plate is controlled to ensure enough crystallization time, the distance between a tow and the hot plate is controlled to ensure the heat treatment efficiency, the three are mutually cooperated, the integrity of fiber crystallization is improved, and further the thermal shrinkage in the fiber application process is reduced, wherein the temperature of the hot plate is too low, and the sufficient energy can be hardly obtained through macromolecular rearrangement; the structure formed originally can be damaged when the temperature of the hot plate is too high; the length of the hot plate is too short, the crystallization time is too short, the integrity of fiber crystallization is influenced, and the thermal shrinkage rate of the fiber is influenced; the length of the hot plate is too long, the efficiency is reduced, and equipment waste is caused; the direct contact between the tows and the hot plate is easily caused when the distance between the tows and the hot plate is too small; excessive tow-to-hot plate distance reduces thermal efficiency.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the distance between the last group of heat setting rollers and the winding roller is 300-400 mm; the distance between the two hot plates and the last group of heat setting rollers is 200-300 mm.

According to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the spinning process parameters of the polyester industrial yarn for the heavy-duty hoisting belt are as follows:

the technological parameters of stretching and heat setting are as follows:

the plying process flow comprises the following steps: creel → sensor → pressure tensioner → godet wheel → guide or networking device → sensor → linear speed inductor → pulley → traveling guide → winding paper tube;

the plying process parameters are as follows: the number of strands is 10-20 and the speed is 400-500 m/min.

The preparation process of the present invention is not limited thereto, and only one possible technical solution is exemplified herein. The specific process parameters are not limited to the above and can be adjusted according to actual requirements.

The invention mechanism is as follows:

in the post-processing and stretching process of the fiber, due to the action of mechanical stress, the fiber orientation degree is greatly increased and has certain crystallinity, so that the fiber elongation and the total deformation work are reduced, but in the stretching process, although most of the deformation generated by the fiber is plastic deformation which can not be recovered at normal temperature, the deformation is often fixed due to crystallization, but part of the deformation is recovered due to the relaxation of tensile stress at room temperature or is subjected to shrinkage recovery in subsequent heat treatment, the shrinkage recovery, namely the shrinkage rate of the fiber in the application process of the fiber, greatly influences the performance (such as safety performance, durability and the like) of the fiber, if the fiber is used as a tire cord, the tire cord is repeatedly stretched, compressed and bent in the use process of the tire, so that the tire is heated, the tire cord is shrunk and creeps, but the cutter cord is likely to delaminate when the tire cord is excessively shrunk, further, the tire is disassembled, which brings great danger to the safety of the tire.

At present, in the spinning and stretching process of the polyester industrial yarn, in order to reduce the shrinkage rate of the polyester industrial yarn as much as possible, after a plurality of stretching processes, tension heat setting (the heat setting roller is adopted to set the fiber under certain tension) is often needed, after tension heat setting, overfeeding with the overfeeding rate of 1-2% is wound, through tension heat setting of the fiber, under the conditions of certain temperature and certain tension, the activity capability of a polymer chain segment is improved, the intermolecular combination is tighter, the average size and the crystallinity of crystal grains of the fiber are improved, so as to reduce the shrinkage rate of the fiber, but because the fiber has certain high elastic deformation in the stretching process, the elastic recovery can be generated under the condition that the tension is reduced, therefore, the speed of a winding head must be lower than the speed of the last group of heat setting rollers, namely, a certain overfeeding rate is needed, so as to ensure that the stretched yarn obtains low tension shrinkage to a certain degree, obtaining satisfactory finished product quality and package, preventing package edge collapse caused by overlarge tension, controlling the overfeeding rate within a certain range (1-2%), and having adverse effect on the finished product quality and the package when the overfeeding rate is overlarge. Although the shrinkage can be reduced to a certain extent by tension heat setting and overfeeding, in the tension heat setting process, the length of the fiber is fixed and can not be changed, so that the folding of macromolecular chains is inhibited, the growth rate of crystal grains is limited, the crystallization defect (the crystallinity is increased less) is caused, and the crystallization defect can not be reduced by controlling the overfeeding alone, so that when the prepared fiber is subjected to heat treatment in the application process, the macromolecular chains and chain segments of the fiber have higher mobility, the de-orientation effect is easy to generate, and the fiber is subjected to a certain amount of shrinkage (the shrinkage is larger).

In fact, the heat setting of the fibers is not only tension heat setting but also relaxation heat setting. The relaxation heat setting is also called as free shrinkage heat setting, namely, the fiber is subjected to heat treatment at a certain temperature under the condition of no tension or small tension, the fiber can be freely shrunk under the condition of the relaxation heat setting, macromolecular chains in an amorphous region easily form folding chains, and further growth of crystal grains is facilitated. At present, the relaxation heat setting is mainly used for carrying out heat setting treatment on polyester short fibers, the heat treatment temperature is low (about 130 ℃), the heat treatment time is long, and the relaxation heat setting is difficult to be suitable for filament production.

According to the invention, the overfeed rate of polyester filament bundle winding is increased to 3-5% in the processing process of the polyester industrial yarn, and meanwhile, a pair of hot plates which are arranged in parallel up and down are arranged between the last heat setting roller and the winding roller in the FDY equipment, so that the polyester filament bundle passes through the two hot plates, the crystallinity of the polyester filament bundle is improved, the high elastic deformation in the polyester filament bundle is recovered, the internal stress of the polyester filament bundle is relaxed by a certain amount, and the shrinkage recovery of the polyester industrial yarn when the polyester industrial yarn is subjected to heat treatment in the application process is reduced. The heat treatment temperature and the higher overfeed rate are matched with each other to reduce the shrinkage rate of the polyester industrial yarn, when the fiber is subjected to heat treatment, macromolecular chains in an amorphous region of the fiber are easy to form folding chains, further growth of crystal grains is facilitated, the crystallinity is increased at the moment, and the fiber can shrink a certain amount along with the increase of the crystallinity. In addition, the heat treatment temperature, the length of the hot plate and the distance between the tows and the hot plate are matched, so that the defect that the relaxation heat treatment in the prior art is not suitable for filament production is overcome, the completeness of fiber crystallization is improved, the stability of fiber size is improved, and the thermal shrinkage in the application process is reduced.

The mechanism for reducing the dosage of the antimony catalyst is as follows:

the polyester catalyst mainly takes antimony compounds such as antimony trioxide, ethylene glycol antimony and antimony acetate as main components, the addition amount of antimony in the industrial polyester synthesis is more than 200ppm, and the antimony is heavy metal, so the restriction on the antimony catalyst is more and more strict due to the advancement of times.

Catalytic activity of the catalyst and specific surface area S of the catalyst_gInternal surface utilization factor f and activity per surface area r_sProportional ratio, and for a certain component of the catalyst, the catalytic activity of the catalyst depends on the specific surface area S of the catalyst_gAnd the internal surface utilization factor f, the activity per unit surface area of the catalyst r_sAt a certain time, the larger the specific surface area, the higher the catalytic activity.

The invention realizes the doping and blending of the metal oxide and the antimony trioxide with certain catalytic polycondensation reaction activity by solution blending, coprecipitation and calcination, wherein the metal oxide is more than one of MgO, CaO, BaO and ZnO, the valence and the valence of the antimony are different, the ionic radius and the antimony are different, and the differences can change the crystal face structure of the antimony trioxide, thereby influencing the related performance. In addition, MgO, CaO, BaO and ZnO are all white crystals, and do not cause color change when used as a polyester catalyst.

The influence of the metal oxide on the antimony trioxide is mainly reflected in that: on the one hand, the metal oxide can inhibit crystallization of the antimony trioxide and growth of cubic antimony trioxide crystal grains, so that the specific surface area S of the antimony trioxide catalyst_gThe catalytic activity of the antimony trioxide is improved; on the other hand, the metal can isomorphously replace the antimony and enter the lattice site of the antimony, so that the antimony trioxide crystal generates defects, the crystal form is changed, the crystal grain size is reduced, and the specific surface area S is increased_gIncreasing the activity r per unit surface area of the crystal by enriching the metal on part of the crystal surface_sThe catalytic activity of the antimony trioxide is improved. If only the metal oxide with certain catalytic polycondensation reaction activity is simply and physically blended with the antimony trioxide, the catalytic activity of the antimony trioxide cannot be obviously improved, because the simple physical blending does not generate crystal defects, the crystal form does not change, the grain size remains unchanged, the total surface area of the crystal does not change, and the catalytic activity cannot be influenced.

According to the invention, the antimony trioxide is doped, so that the catalytic activity of the antimony trioxide is improved to a certain extent, the improvement of the catalytic activity of the antimony trioxide is beneficial to reducing the usage amount of the antimony trioxide, and in the polyester synthesis process, under the condition that the polycondensation process conditions are unchanged and the polyester achieves the same index, the usage amount of the antimony trioxide can be reduced by more than 30% after the antimony trioxide is doped by adopting the metal oxide, so that the problem of large addition amount of the existing antimony trioxide is effectively solved, and meanwhile, the requirement of polyester production can be met.

Has the advantages that:

(1) according to the preparation method of the polyester industrial yarn for the heavy-duty hoisting belt, the completeness of fiber crystallization is improved and the thermal shrinkage in the application process is reduced through the mutual matching of the heat treatment temperature and the higher overfeed rate;

(2) the invention relates to a preparation method of polyester industrial yarn for heavy-duty hoisting belts,the specific surface area S of the antimony trioxide is improved by doping and modifying the antimony trioxide by the metal oxide with certain catalytic activity_gAnd activity per unit surface area r_sThereby improving the catalytic activity of the antimony trioxide and improving the polymerization efficiency; and the addition amount of the antimony catalyst during polyester synthesis can be reduced while the production requirement of the polyester is met, the antimony emission of the subsequently prepared fiber is effectively reduced, and the environment-friendly production is favorably realized.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

A preparation method of polyester industrial yarn for heavy-duty hoisting belts comprises the following specific steps:

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Mg (NO) at a concentration of 0.8 mol%₃)₂Aqueous solution with Sb concentration of 8 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and Mg in the mixed solution²⁺And Sb³⁺In a molar ratio of 2: 100;

(1.1.2) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 9 to obtain a precipitate, and then washing and drying the precipitate at the temperature of 105 ℃ for 2.5 hours;

(1.1.3) heating the dried product to 400 ℃ firstly, then preserving heat for 2.5h, then heating to 900 ℃ and preserving heat for 1.5h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:1.2 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.1MPa, the esterification reaction temperature is 250 ℃, the esterification reaction endpoint is when the water distillate in the esterification reaction reaches 93 percent of the theoretical value, and the modified Sb is doped₂O₃The addition amounts of the powder, the titanium dioxide and the triphenyl phosphate are respectively 0.012 wt%, 0.20 wt% and 0.02 wt% of the addition amount of the terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 480Pa within 30min, controlling the reaction temperature to be 250 ℃ and the reaction time to be 31min, then continuing to pump vacuum, and carrying out the polycondensation reaction in the high vacuum stage to further reduce the reaction pressure to absolute pressure of 100Pa, control the reaction temperature to be 270 ℃ and control the reaction time to be 50min, thus obtaining the polyester;

(1.4) performing solid-phase polycondensation tackifying on the polyester to obtain a polyester melt with the intrinsic viscosity of 1.0 dL/g;

(2) melting, metering, extruding, cooling, oiling, plying, stretching, twisting, heat setting, relaxation heat treatment and winding the polyester melt to prepare the polyester industrial yarn for the heavy-duty hoisting belt;

the relaxation heat treatment is that the polyester filament bundle with 4.9% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 200 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 3.0m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, the distance between the polyester filament bundle and the two hot plates is 5mm when the polyester filament bundle passes through the middle of the two hot plates, the distance between the last group of heat setting rollers and the winding rollers is 300mm, and the distance between the two hot plates and the last group of heat setting rollers is 200 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: number of strands 10, speed 400 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 9.0dtex, the breaking strength of 8.4N, the linear density of 4400dtex, the linear density deviation rate of 0.5 percent, the elongation at break of 9.5 percent, the dry heat shrinkage rate of 9.5 percent under the condition of 177 ℃ of × 10min × 0.05.05 cN/dtex, and the network degree of 14/m.

Comparative example 1

The preparation method of the polyester industrial yarn has the basically same steps as the example 1, and is different from the step (1) in that the conventional Sb is adopted₂O₃Replacement of Sb modified by doping₂O₃Powder, conventional Sb₂O₃The addition amount of (3) is 0.03 wt% of the addition amount of terephthalic acid, the step (2) does not go through the relaxation heat treatment process, the winding speed is 2680m/min, the winding overfeed rate is 1.47%, the filament number of the produced polyester industrial yarn is 9.0dtex, the breaking strength is 8.3N, the linear density is 4400dtex, the deviation rate of the linear density is 0.5%, the elongation at break is 9.5%, the dry heat shrinkage rate under the condition of × 0.05.05 cN/dtex at 177 ℃ × 10min is 11.5%, and the network degree is 14/m.

Comparative example 2

The preparation method of the polyester industrial yarn has the basically same steps as the example 1, and is different from the step (1) in that the conventional Sb is adopted₂O₃Replacement of Sb modified by doping₂O₃Powder, conventional Sb₂O₃The amount of (B) added was 0.03 wt% based on the amount of terephthalic acid added. The filament number of the prepared polyester industrial yarn is 9.0dtex, the breaking strength is 8.4N, the linear density is 4400dtex, and the linear density is 4400dtexThe degree deviation was 0.5%, the elongation at break was 9.3%, the dry heat shrinkage at 177 ℃ of × 10min × 0.05.05 cN/dtex was 9.2%, and the degree of network was 14/m.

Comparative example 3

A preparation method of the polyester industrial yarn has the same steps as the example 1, except that the step (2) does not carry out a relaxation heat treatment process, the winding speed is 2680m/min, the winding overfeed rate is 1.47 percent, the filament number of the prepared polyester industrial yarn is 9.0dtex, the breaking strength is 8.2N, the linear density is 4400dtex, the deviation rate of the linear density is 0.5 percent, the elongation at break is 10.5 percent, the dry heat shrinkage rate under the condition of × 10min × 0.05.05 cN/dtex at 177 ℃ is 12.5 percent, and the network degree is 14/m.

By comprehensively analyzing the example 1 and the comparative examples 1 to 3, the invention can find that the doped modified Sb is adopted₂O₃Powder replacing conventional Sb₂O₃The catalyst is obviously reduced while the same catalytic activity is ensured, and the aim of reducing the discharge of antimony is achieved. The invention also obviously reduces the dry heat shrinkage rate of the polyester industrial yarn by adding the relaxation heat treatment process.

Example 2

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Ca (NO) was added at a concentration of 0.5 mol%₃)₂Aqueous solution with Sb concentration of 5 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution (A) is oxalic acid, and Ca is contained in the mixed solution²⁺And Sb³⁺In a molar ratio of 1: 100;

(1.1.2) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 10 to obtain a precipitate product, and then washing and drying the precipitate product at the drying temperature of 110 ℃ for 2 hours;

(1.1.3) heating the dried product to 400 ℃ firstly, then preserving heat for 2h, then heating to 900 ℃ and preserving heat for 1h, finally cooling in the air and crushingThe obtained doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:1.5 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and trimethyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is normal pressure, the esterification reaction temperature is 251 ℃, the esterification reaction endpoint is when the water distillate in the esterification reaction reaches 92% of a theoretical value, and modified Sb is doped₂O₃The adding amount of the powder, the titanium dioxide and the trimethyl phosphate is respectively 0.014 wt%, 0.22 wt% and 0.01 wt% of the adding amount of the terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the condition of negative pressure, stably pumping the pressure in the stage from normal pressure to the absolute pressure of 500Pa within 30min, controlling the reaction temperature to be 252 ℃ and the reaction time to be 30min, then continuously pumping the vacuum to perform the polycondensation reaction in a high vacuum stage, further reducing the reaction pressure to the absolute pressure of 100Pa, controlling the reaction temperature to be 271 ℃ and controlling the reaction time to be 55min, and obtaining the polyester;

the relaxation heat treatment is that the polyester filament bundle with 4.2% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 207 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 3.2m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, when the polyester filament bundle passes through the middle of the two hot plates, the distance between the polyester filament bundle and the two hot plates is 6mm, the distance between the last group of heat setting rollers and the winding rollers is 311mm, and the distance between the two hot plates and the last group of heat setting rollers is 220 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: the number of strands was 20 and the speed was 500 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 8.5dtex, the breaking strength of 8.4N, the linear density of 3600dtex, the linear density deviation rate of-1.0 percent, the elongation at break of 8.0 percent, the dry heat shrinkage rate of 8.8 percent under the condition of 177 ℃ of × 10min × 0.05.05 cN/dtex, and the network degree of 7/m.

Example 3

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Ba (NO) was added at a concentration of 1.0 mol%₃)₂Aqueous solution with 10 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution (A) is oxalic acid, and Ba in the mixed solution²⁺And Sb³⁺In a molar ratio of 3: 100;

(1.1.2) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 9.5 to obtain a precipitate, and then washing and drying the precipitate at the temperature of 105 ℃ for 3 hours;

(1.1.3) heating the dried product to 400 ℃ firstly, then preserving heat for 3h, heating to 900 ℃ and then preserving heat for 2h, cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.5 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:1.8 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and trimethyl phosphite, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is normal pressure, the esterification reaction temperature is 252 ℃, when the water distillate in the esterification reaction reaches 90% of a theoretical value, the esterification reaction end point is used, and modified Sb is doped₂O₃The addition amounts of the powder, titanium dioxide and trimethyl phosphite are respectively 0.013 wt%, 0.23 wt% and 0.03 wt% of the addition amount of terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, smoothly pumping the pressure in the low vacuum stage from normal pressure to the absolute pressure of 450Pa within 35min, controlling the reaction temperature to be 253 ℃ and controlling the reaction time to be 35min, then continuously pumping the vacuum to perform the polycondensation reaction in the high vacuum stage, further reducing the reaction pressure to the absolute pressure of 90Pa, controlling the reaction temperature to be 274 ℃ and controlling the reaction time to be 60min, and preparing the polyester;

(1.4) performing solid-phase polycondensation tackifying on the polyester to obtain a polyester melt with the intrinsic viscosity of 1.1 dL/g;

the relaxation heat treatment is that the polyester filament bundle with 3% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 215 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 3.3m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, the distance between the polyester filament bundle and the two hot plates is 7mm when the polyester filament bundle passes through the middle of the two hot plates, the distance between the last group of heat setting rollers and the winding rollers is 335mm, and the distance between the two hot plates and the last group of heat setting rollers is 235 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: the number of strands was 15 and the speed was 450 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 8.5dtex, the breaking strength of 8.6N, the linear density of 3800dtex, the linear density deviation rate of 0.7 percent, the elongation at break of 8.0 percent, the dry heat shrinkage rate of 7.0 percent under the condition of 177 ℃ of × 10min × 0.05.05 cN/dtex, and the network degree of 6/m.

Example 4

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Zn (NO) at a concentration of 0.6 mol%₃)₂Aqueous solution with Sb concentration of 6 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and Zn is contained in the mixed solution²⁺And Sb³⁺In a molar ratio of 1.2: 100;

(1.1.2) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 10 to obtain a precipitate product, and then washing and drying the precipitate product at the drying temperature of 110 ℃ for 2.5 hours;

(1.1.3) heating the dried product to 400 ℃, then preserving heat for 2.5h, then heating to 900 ℃, then preserving heat for 1h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:1.9 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.3MPa, the temperature of the esterification reaction is 254 ℃, the end point of the esterification reaction is when the distilled amount of water in the esterification reaction reaches 96% of the theoretical value, and the modified Sb is doped₂O₃The addition amounts of the powder, the titanium dioxide and the triphenyl phosphate are respectively 0.012 wt%, 0.25 wt% and 0.05 wt% of the addition amount of the terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, smoothly pumping the pressure in the stage from normal pressure to the absolute pressure of 410Pa within 40min, controlling the reaction temperature to be 255 ℃ and the reaction time to be 32min, then continuing to pump vacuum, and carrying out the polycondensation reaction in the high vacuum stage, so that the reaction pressure is further reduced to the absolute pressure of 95Pa, the reaction temperature is 275 ℃ and the reaction time is 70min, thus obtaining the polyester;

(1.4) performing solid-phase polycondensation tackifying on the polyester to obtain a polyester melt with the intrinsic viscosity of 1.2 dL/g;

the relaxation heat treatment is that the polyester filament bundle with 4.8% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 222 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 3.4m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, when the polyester filament bundle passes through the middle of the two hot plates, the distance between the polyester filament bundle and the two hot plates is 8mm, the distance between the last group of heat setting rollers and the winding rollers is 346mm, and the distance between the two hot plates and the last group of heat setting rollers is 250 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: number of strands 20, speed 400 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 8.2dtex, the breaking strength of 8.4N, the linear density of 3500dtex, the linear density deviation rate of-0.6 percent, the elongation at break of 7.2 percent, the dry heat shrinkage rate of 9.0 percent under the condition of 177 ℃ of × 10min × 0.05.05 cN/dtex, and the network degree of 10/m.

Example 5

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Mg (NO) at a concentration of 0.7 mol%₃)₂Aqueous solution with Sb concentration of 8 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and Mg in the mixed solution²⁺And Sb³⁺In a molar ratio of 2: 100;

(1.1.3) heating the dried product to 400 ℃ firstly, then preserving heat for 2.5h, heating to 900 ℃ and preserving heat for 2h, cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.5 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:2.0 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and trimethyl phosphite, pressurizing in nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.2MPa, the esterification reaction temperature is 256 ℃, the esterification reaction endpoint is when the water distillate in the esterification reaction reaches 99% of the theoretical value, and modified Sb is doped₂O₃The addition amounts of the powder, the titanium dioxide and the trimethyl phosphite are respectively 0.012 wt%, 0.20 wt% and 0.04 wt% of the addition amount of the terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 490Pa within 45min, controlling the reaction temperature to 257 ℃ and the reaction time to 40min, then continuing to pump vacuum, and carrying out the polycondensation reaction in the high vacuum stage to further reduce the reaction pressure to absolute pressure of 90Pa, the reaction temperature to 277 ℃ and the reaction time to 75min, thus obtaining the polyester;

(1.4) performing solid-phase polycondensation tackifying on the polyester to obtain a polyester melt with the intrinsic viscosity of 1.05 dL/g;

the relaxation heat treatment is that the polyester filament bundle with 4.0% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 232 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 3.6m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, when the polyester filament bundle passes through the middle of the two hot plates, the distance between the polyester filament bundle and the two hot plates is 8.5mm, the distance between the last group of heat setting rollers and the winding rollers is 368mm, and the distance between the two hot plates and the last group of heat setting rollers is 260 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: the number of strands was 12 and the speed was 420 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 8.8dtex, the breaking strength of 8.5N, the linear density of 4000dtex, the linear density deviation rate of 2.0 percent, the elongation at break of 8.1 percent, the dry heat shrinkage rate of 8.3 percent under the condition of 177 ℃ of × 10min of × 0.05.05 cN/dtex, and the network degree of 10/m.

Example 6

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Mg (NO) was added in a concentration of 0.8 mol% in each case₃)₂Mixing the aqueous solution with Ca (NO)₃)₂Mixing the aqueous solution according to the volume ratio of 1:1 to obtain M containing metal ions^x+Aqueous solution of (2), containing metal ions M^x+With 8 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and M in the mixed solution^x+And Sb³⁺In a molar ratio of 2.5: 100;

(1.1.2) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 10 to obtain a precipitate product, and then washing and drying the precipitate product at the drying temperature of 105 ℃ for 3 hours;

(1.1.3) heating the dried product to 400 ℃ firstly, then preserving heat for 3h, heating to 900 ℃ and then preserving heat for 1.5h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:1.2 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and trimethyl phosphate, pressurizing in nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.2MPa, the esterification reaction temperature is 258 ℃, the esterification reaction endpoint is when the water distillate in the esterification reaction reaches 95% of a theoretical value, and modified Sb is doped₂O₃The adding amount of the powder, the titanium dioxide and the trimethyl phosphate is respectively 0.0135 wt%, 0.23 wt% and 0.01 wt% of the adding amount of the terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 430Pa within 35min, the reaction temperature of 258 ℃ and the reaction time of 40min, then continuing to pump vacuum to perform the polycondensation reaction in the high vacuum stage, further reducing the reaction pressure to absolute pressure of 94Pa, the reaction temperature of 280 ℃ and the reaction time of 80min, and obtaining the polyester;

the relaxation heat treatment is that the polyester filament bundle with 3.0% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 235 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 3.8m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, when the polyester filament bundle passes through the middle of the two hot plates, the distance between the polyester filament bundle and the two hot plates is 9mm, the distance between the last group of heat setting rollers and the winding rollers is 384mm, and the distance between the two hot plates and the last group of heat setting rollers is 280 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: the number of strands was 18 and the speed was 480 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 8.0dtex, the breaking strength of 8.2N, the linear density of 3300dtex, the linear density deviation rate of 1.2 percent, the elongation at break of 9.5 percent, the dry heat shrinkage rate of 7.0 percent under the condition of 177 ℃ of × 10min × 0.05.05 cN/dtex, and the network degree of 6/m.

Example 7

(1) preparing polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(1.1.1) Mg (NO) was added in a concentration of 0.5 mol% in each case₃)₂Aqueous solution, Ba (NO)₃)₂Mixing the aqueous solution with Ca (NO)₃)₂Mixing the aqueous solution according to the volume ratio of 1:1:1 to obtain M containing metal ions^x+Aqueous solution of (2), containing metal ions M^x+With 10 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and the metal ions M in the mixed solution^x+And Sb³⁺In a molar ratio of 2: 100;

(1.1.2) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 9 to obtain a precipitate, and then washing and drying the precipitate at the temperature of 108 ℃ for 2.5 hours;

(1.1.3) heating the dried product to 400 ℃, then preserving heat for 2.5h, then heating to 900 ℃, then preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) esterification reaction;

preparing terephthalic acid and ethylene glycol with the molar ratio of 1:2.0 into slurry, and adding doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.3MPa, the esterification reaction temperature is 260 ℃, the esterification reaction endpoint is when the water distillate in the esterification reaction reaches 91% of the theoretical value, and modified Sb is doped₂O₃The adding amount of the powder, the titanium dioxide and the triphenyl phosphate is respectively 0.015 wt%, 0.25 wt% and 0.05 wt% of the adding amount of the terephthalic acid;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, smoothly pumping the pressure in the stage from normal pressure to the absolute pressure of 400Pa within 50min, controlling the reaction temperature to be 260 ℃ and the reaction time to be 50min, then continuing to pump vacuum, and carrying out the polycondensation reaction in the high vacuum stage to further reduce the reaction pressure to the absolute pressure of 88Pa, control the reaction temperature to be 282 ℃ and control the reaction time to be 90min, thus obtaining the polyester;

(1.4) performing solid-phase polycondensation tackifying on the polyester to obtain a polyester melt with the intrinsic viscosity of 1.15 dL/g;

the relaxation heat treatment is that the polyester filament bundle with 5.0% of winding overfeed rate passes through a space between a pair of hot plates which are arranged in parallel and are not coplanar and have the temperature of 240 ℃, the hot plates are positioned between the last group of heat setting rollers and the winding rollers in the FDY equipment, the length of the two hot plates is 4.0m along the running direction of the polyester filament bundle, the two ends of the two hot plates are flush, when the polyester filament bundle passes through the middle of the two hot plates, the distance between the polyester filament bundle and the two hot plates is 10mm, the distance between the last group of heat setting rollers and the winding rollers is 400mm, and the distance between the two hot plates and the last group of heat setting rollers is 300 mm;

the spinning process parameters are as follows:

the technological parameters of stretching and heat setting are as follows:

the stranding process flow is as follows: creel → sensor → pressure tensioner → godet wheel → guide bar or network → sensor → linear speed inductor → pulley → stroke guide → winding paper tube, the technological parameters of plying are: the number of strands was 16 and the speed was 420 m/min.

The finally prepared polyester industrial yarn for the heavy-duty hoisting belt has the filament number of 8.4dtex, the breaking strength of 8.6N, the linear density of 4000dtex, the linear density deviation rate of-2.0 percent, the elongation at break of 6.9 percent, the dry heat shrinkage rate of 10.0 percent under the condition of 177 ℃ of × 10min × 0.05.05 cN/dtex, and the network degree of 8/m.

Claims

1. The preparation method of the polyester industrial yarn for the heavy-duty hoisting belt is characterized by comprising the following steps of: performing solid phase polycondensation tackifying, melting, metering, extruding, cooling, oiling, plying, stretching, twisting, heat setting, relaxation heat treatment and winding on the polyester melt to obtain the polyester industrial yarn for the heavy-duty hoisting belt;

Sb₂O₃the doping modification process comprises the following steps: firstly, containing metal ions M^x+With Sb-containing solution³⁺Uniformly mixing the solution, then dropwise adding a precipitator until the pH value of the mixed solution is 9-10, and finally calcining and crushing a precipitation product; metal ion M^x+Is Mg²⁺、Ca²⁺、Ba²⁺And Zn²⁺One or more of (1); at the beginning of the precipitation, the metal ions M in the mixed solution^x+And Sb³⁺The molar ratio of (A) to (B) is 1-3: 100;

the certain temperature is 200-240 ℃.

2. The method for preparing the industrial polyester yarn for the heavy-duty hoisting belt according to claim 1, wherein the industrial polyester yarn for the heavy-duty hoisting belt has a single-filament fineness of 8.0 to 9.0dtex, a breaking strength of not less than 8.2N, a linear density of 3300 to 4400dtex, a linear density deviation rate of ± 2.0%, an elongation at break of 6.5 to 9.5%, a dry heat shrinkage rate of 7.0 to 10.0% under 177 ℃ × 10min × 0.05.05 cN/dtex conditions, and a network degree of 6 to 14 counts/m.

3. The method for preparing the industrial polyester yarn for heavy-duty hoisting belts according to claim 1, wherein the metal ion M is contained^x+The concentration of the solution is 0.5-1.0 mol%, the solvent is water, and the anion in the solution is NO₃ ^-(ii) a The Sb-containing compound³⁺The solution of (a) is Sb with the concentration of 5-10 mol%₂O₃The solvent of (1) is oxalic acid; the precipitator is ammonia water with the concentration of 2 mol/L;

4. The method for preparing the industrial polyester yarn for the heavy-duty hoisting belt according to claim 3, wherein the polyester before solid-phase polycondensation and tackifying is prepared by the following steps:

(1) performing esterification reaction;

(2) performing polycondensation reaction;

5. The preparation method of the industrial polyester yarn for the heavy-duty hoisting belt according to claim 4, wherein the molar ratio of terephthalic acid to ethylene glycol is 1: 1.2-2.0, and the doped and modified Sb is₂O₃The addition amounts of the powder, the delustering agent and the stabilizer are respectively 0.012-0.015 wt%, 0.20-0.25 wt% and 0.01-0.05 wt% of the addition amount of the terephthalic acid.

6. The method for preparing the industrial polyester yarn for the heavy-duty hoisting belt according to claim 5, wherein the matting agent is titanium dioxide, and the stabilizer is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

7. The preparation method of the industrial polyester yarn for the heavy-duty hoisting belt according to claim 6, wherein the intrinsic viscosity of the polyester after solid phase polycondensation and tackifying is 1.0-1.2 dL/g.

8. The method for preparing the industrial polyester yarn for the heavy-duty hoisting belt according to claim 1, wherein the space with a certain temperature is a space between a pair of hot plates which are arranged in parallel and are not coplanar, and the hot plates are positioned between the last group of heat setting rollers and the winding roller in the FDY equipment; the length of the two hot plates is 3.0-4.0 m along the running direction of the polyester tows, and the two ends of the two hot plates are flush; when the polyester tows pass through the middle of the two hot plates, the distance between the polyester tows and the two hot plates is 5-10 mm.

9. The preparation method of the industrial polyester yarn for the heavy-duty hoisting belt according to claim 8, wherein the distance between the last group of heat setting rollers and the winding roller is 300-400 mm; the distance between the two hot plates and the last group of heat setting rollers is 200-300 mm.

10. The preparation method of the polyester industrial yarn for the heavy-duty hoisting belt according to claim 1, wherein the spinning process parameters of the polyester industrial yarn for the heavy-duty hoisting belt are as follows:

the technological parameters of stretching and heat setting are as follows: