Preparation method of geotextile polyester industrial yarn

Abstract

The application relates to a preparation method of geotextile polyester industrial yarn, which adopts a melt direct spinning production mode, and the post-drawing process is 6 pairs or 7 pairs of hot roller drawing; when the 6 pairs of hot roller drawing is adopted, GR4 and GR5 are setting rollers, the temperature of GR4 is 190-210 DEG C, the temperature of GR5 is 210-230 DEG C, and the temperature of GR6 is lower than 80 DEG C; the speed ratio of GR5 to GR4 is 1.002-1.020; when the 7 pairs of hot roller drawing is adopted, GR4, GR5 and GR6 are setting rollers, the temperature of GR4 is 190-210 DEG C, the temperature of GR5 is 210-220 DEG C, the temperature of GR6 is 220-230 DEG C, and the temperature of GR7 is lower than 80 DEG C. The method is based on the existing equipment and production technology, is convenient to implement, and has the characteristics of high strength, ultra-low elongation, high rigidity, excellent long-time stability and the like, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polyester industrial yarn technology, and relates to a method for preparing polyester industrial yarn for geotechnical applications. Background Technology

[0002] Polyester fiber is the highest-volume chemical fiber. Polyester industrial yarn, used in industry, is widely used in safety belts, lifting slings, geotextiles, automotive cords, cables, and conveyor belts due to its high strength, high modulus, and good heat resistance. By 2021, China's polyester industrial yarn production capacity accounted for approximately two-thirds of the global total. However, it also faces challenges such as product homogenization, severe product homogenization, and low technological content. Therefore, improving performance and quality is the future direction for polyester industrial yarn development. Based on performance, polyester industrial yarn can be categorized into high-strength, high-strength low-elongation, high-modulus low-shrinkage, and high-strength low-shrinkage types. Low-elongation polyester industrial yarn, in addition to the common characteristics of high breaking strength and high modulus found in industrial yarns, uniquely features low breaking elongation, meaning excellent dimensional stability under stress. It is widely used in geotechnical engineering (such as geogrids), rubber reinforcement (conveyor belts, oil pipelines, hoses, etc.), and marine development (cables for offshore oil platforms, ships, etc.). Currently, due to limitations in technology, the requirements for physical properties of low-elongation polyester industrial yarn are mainly based on the breaking elongation rate, while meeting basic strength requirements. In terms of production technology, the preparation of low-elongation polyester industrial yarn primarily involves technological innovation at the raw material and process levels. At the raw material level, this mainly includes improving raw material quality and modification techniques.

[0003] The quality of raw materials can be improved by increasing their molecular weight (intrinsic viscosity) and controlling impurities. Patent application CN201310621731.3 discloses a production process for high-strength, low-elongation polyester industrial yarn, using PET viscosity chips with an intrinsic viscosity of 1.5–1.6 dl / g as the raw material for preparation. Currently, in industrial production, due to limitations in PET viscosity chip thickening technology, the commonly used chip viscosity range is 0.90–1.20 dl / g. The preparation of high-viscosity (1.5–1.6 dl / g) PET is not yet mass-produced due to technological bottlenecks and the high energy consumption associated with thickening. Patent application CN201511016778.2 discloses a high-strength, low-elongation polyester industrial yarn and its preparation method, obtained by polyester washing, solid-phase thickening, and spinning. The high-strength, low-elongation polyester industrial yarn has a breaking strength ≥8.3 cN / dtex and a breaking elongation of 10.0 ± 1.5%. Using a mixture of magnesium glycolate and antimony glycolate as a polycondensation catalyst results in a very low thermal degradation coefficient, reducing oligomers during polymerization and decreasing thermal degradation during processing. This significantly reduces impurities in the polyester and also lowers the amount of nucleating agents, increasing the probability of homogeneous nucleation while reducing heterogeneous nucleation. Washing further reduces oligomer content, which is beneficial for grain growth and optimized crystallinity in high-strength, low-elongation polyester industrial fibers. However, due to limitations in polymerization technology, scale, and equipment, catalyst replacement requires systematic and detailed validation before gradual scaling up. Currently, it is generally carried out on small-scale polymerization production lines. Furthermore, washing consumes large amounts of water and solvents, especially toxic, harmful, and volatile organic solvents such as ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether, posing a significant challenge to production safety and environmental protection.

[0004] The modification of raw materials mainly involves two methods: copolymerization and blending. Patent application CN201811615802.8 discloses a method for preparing polyester industrial yarn for geogrids. This involves uniformly mixing terephthalic acid, ethylene glycol, and 2,2,3,4,5,5-hexamethyl-3,4-hexanediol, followed by esterification and polycondensation reactions to prepare modified polyester. This modified polyester is then subjected to solid-state polycondensation for thickening before spinning. The prepared yarn exhibits a breaking strength ≥8.5 cN / dtex and a breaking elongation of 18.0–20.0%, classifying it as a high-elongation type. Patent application CN202011607901.9 discloses a high-strength, low-elongation polyester industrial yarn and its preparation method. This involves solid-state polycondensation of copolymerized modified polyester for thickening, followed by spinning, winding, and coordination treatment to obtain the high-strength, low-elongation polyester industrial yarn. The 2,5-pyridinedicarboxylic acid segments are mixed with Fe... 3+Coordination increases physical crosslinking points, thereby significantly improving tensile strength. Performance indicators are: tensile strength ≥ 9.0 cN / dtex, and elongation at break 10.8 ± 0.5%. Patent application CN201610776464.0 discloses a high-uniformity, high-strength, low-elongation polyester industrial filament and its preparation method. The raw material for the polyester fiber is a modified polyester composed of terephthalic acid segments, ethylene glycol segments, and branched diol segments. The performance indicators of the obtained high-uniformity, high-strength, low-elongation polyester industrial filament are: tensile strength ≥ 8.3 cN / dtex, and elongation at break 10.0 ± 1.5%. Patent application CN201310478959 discloses a high-strength, low-elongation industrial yarn of marine-grade creep-resistant polyester and its preparation method. The method involves increasing the viscosity of polyester through solid-phase polycondensation, then blending it with a fluorinated epoxy compound and a carbodiimide stabilizer to obtain high-viscosity creep-resistant polyester chips as raw material. The resulting high-strength, low-elongation industrial yarn exhibits the following performance indicators: breaking strength ≥ 8.3 cN / dtex, and breaking elongation 10.0 ± 1.5%. While raw material modification improves the performance indicators of polyester to some extent, it is highly unfavorable for production conversion, involving a long process route and requiring adjustments to existing processes due to material changes. Furthermore, functional additives altering the polyester molecular structure may degrade other performance indicators.

[0005] Technological innovations in processes, oiling, and equipment are characterized by strong operability, ease of conversion and implementation, and low cost, and are currently the main direction of efforts to improve the technology of low-elongation polyester industrial yarn. Patent application CN201811078697.9 discloses a high-modulus, low-elongation polyester industrial yarn for geotextiles and its production method. It employs a solid-phase polymerization reactor for thickening, combined with a multi-head spinning process, two-stage drafting and one-stage relaxation heat setting, and high-speed winding using a twin-head winding machine. This achieves solid-phase thickening, multi-head direct spinning of high-modulus, low-elongation polyester industrial yarn for geotextiles. The performance of the polyester industrial yarn meets the requirements of geotextiles, primarily through the setting of the draft ratio, relaxation ratio, and drafting and relaxation temperatures. Specifically, the breaking elongation is controlled within 12.5%. Patent application CN201711340317.X discloses a method for preparing high-strength, low-elongation polyester industrial yarn. It uses an emulsion containing crown ether oil for oiling and adjusts the spinning process parameters and the stretching and heat-setting process parameters. The high-strength, low-elongation polyester industrial yarn has a breaking strength ≥ 8.3 cN / dtex and a breaking elongation at center value of 11.0–12.0%. Patent application CN201610797955.3 discloses a spinneret with varying fineness and a method for producing high-strength, low-elongation industrial yarn for high-abrasion-resistant marine cables. It designs and uses a spinneret for high-strength, low-elongation industrial yarn, and the industrial yarn performance indicators are: breaking strength > 8.4 cN / dtex and breaking elongation < 12%. Invention patent application CN201210322435.9 discloses a method for manufacturing high-strength, low-elongation polyester industrial yarn, featuring a unique cooling system comprising four parts: slow cooling, pre-cooling, windless zone cooling, and air-blowing cooling. The pre-cooling is an active outer ring pre-cooling system, and the active outer ring device uses a hollowed-out annular belt to improve cooling efficiency. The industrial yarn performance indicators are: breaking strength ≥ 8.3 cN / dtex, and breaking elongation 10.0 ± 1.5%. Utility model patent application CN201220475577.4 discloses a slow cooler for producing low-elongation, low-shrinkage industrial yarn, also making technical improvements in yarn cooling. The invention patent with application number CN201210299931.7 discloses a high-strength, ultra-low elongation polyester industrial filament for seat belts and its manufacturing method. The method includes: preparation of high-viscosity polyester chips, removal of impurities from high-viscosity polyester chips, melt spinning, drawing, heat setting, and winding. The polyester industrial filament has a fiber count of 72-144F and a fineness of 1100-2222 dtex. The performance indicators are: breaking strength can reach above 7.80 cN / dtex, and breaking elongation can reach at least 10%-14%. The paper "Research on High-Strength, Low-Elongation Polyester Filaments and Products" (Industrial Textiles, 1992, (2):8) reported on the process test of high-strength, low-elongation polyester filament using domestic production line equipment. The high-strength, low-elongation polyester filament produced had a strength greater than 6.7 cN / dtex and an elongation of less than 14%.The paper "Preparation and Mechanical Properties Study of High-Strength Low-Elongation Polyester Industrial Yarn" (Synthetic Fiber Industry, 2017, 40(4):1) reported that high-strength low-elongation polyester industrial yarn was prepared by a process route of high stretching and low-temperature tension heat setting. The high-strength low-elongation polyester industrial yarn prepared had a breaking strength of 8.55 cN / dtex and a breaking elongation of 12.7%.

[0006] Based on existing publicly available technologies, whether through improvements in raw material quality or technological upgrades to existing spinning processes and equipment, the core physical property of low-elongation polyester industrial yarn—elongation at break—currently ranges from 10% to 14% while meeting basic strength requirements, and the technological bottleneck of achieving 10% elongation remains difficult to overcome. Regarding comprehensive evaluation indicators, existing indicators are generally limited to elongation at break, lacking evaluation indicators for dimensional rigidity and stability. This is mainly due to the limitations of existing technologies. Current production of low-elongation polyester industrial yarn is based on polyester melt spinning (melt-spinning-drawing-winding) processes and equipment. Under existing high-speed winding spinning technology, all core technologies focus on improving fiber orientation, especially amorphous orientation. Achieving this structural control, under current technological conditions, can only be achieved by reducing the disorientation caused by setting, i.e., lowering the setting temperature, overfeed rate, and accelerating cooling and solidification. However, this process has a drawback: incomplete fiber crystallization and an excessively large proportion of amorphous regions. Highly oriented amorphous structures are thermo-equilibrium unstable structures. Therefore, after winding, under varying environmental temperatures and humidity conditions, stress relaxation gradually occurs, the amorphous regions deorient, chains break and shrink, resulting in increased elongation at break and deterioration in rigidity and stability. Currently, with continuous technological innovation and rapid development in transportation (such as high-speed railways and large airports), offshore oil extraction, and infrastructure construction, the technical requirements for low-elongation polyester industrial yarns are constantly increasing. Existing products have relatively high elongation at break (poor load-bearing stability), and the single yarn spool's elongation at break is limited. 5％ Fluctuation > 5.0%, in the stiffness parameter r 5％ The elongation-to-length ratio is 40%, and the long-term stability index, the elongation-to-length ratio per million hours, is above 1.500, which is insufficient to meet the requirements for high performance. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a method for preparing polyester industrial yarn for geotechnical applications.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing polyester industrial yarn for geotextiles, which adopts melt spinning production method, and the post-drawing process is drawn by 6 pairs of hot rollers, the 6 pairs of hot rollers are GR1 to GR6, and GR4 and GR5 are shaping rollers;

[0010] The temperature of GR4 is 190-210℃, the temperature of GR5 is 210-230℃, and the temperature of GR6 is below 80℃; the speed ratio of GR5 to GR4 is 1.002-1.020.

[0011] As a preferred technical solution:

[0012] The method for preparing geotextile polyester industrial yarn as described above provides the following performance indicators for the geotextile polyester industrial yarn: breaking strength ≥ 8.20 cN / dtex, breaking elongation 10.0 ± 1.0%, shrinkage 10 ± 1.5%, and r 5％ ≥50.0%, single spool r 5％ Fluctuation <3.0%, 10 4 Elongation ratio after hours <1.400;

[0013] r 5％ This refers to the strength value (σ) corresponding to a fiber deformation elongation of 5%. 5％ The percentage of the fracture strength (σ) to the total fracture strength;

[0014] Single spool r 5％ Fluctuation refers to a full-bore test performed on a single yarn spool, starting from the yarn head at the outer end of the spool and working inwards to the innermost tail end, measuring all r values. 5％ The maximum fluctuation value;

[0015] 10 4 Elongation ratio after 10 hours refers to the elongation ratio after being placed at room temperature for 10 hours. 4 The ratio of fiber breaking elongation to initial breaking elongation after hours.

[0016] The method for preparing geotextile polyester industrial yarn as described above, wherein the fiber orientation degree of the geotextile polyester industrial yarn is 0.935-0.965, the amorphous region orientation degree is 0.820-0.840, and the crystallinity is 62.0-65.0%.

[0017] The method for preparing geotextile polyester industrial yarn as described above includes the following conditions: GR1 temperature is 60-70℃, GR2 temperature is 90-100℃, GR3 temperature is 125-135℃, GR1 speed is 500-650m / min, the speed ratio of GR2 to GR1 is 1.0-1.1, the speed ratio of GR3 to GR2 is 3.9-4.5, the speed ratio of GR4 to GR3 is 1.3-1.5, and the speed ratio of GR6 to GR5 is 0.98-1.002; the winding tension is 250-350N / 1000D, and the winding speed is 2800-3500m / min.

[0018] In the preparation method of the above-mentioned geotextile polyester industrial yarn, an air-cooling device is provided on the yarn path before winding of GR6 to blow the yarn. The number of air-cooling devices is 1 to 4 sets, and the blowing temperature is 20 to 30°C.

[0019] The present invention also provides another method for preparing polyester industrial yarn for geotextiles, which adopts melt direct spinning production method, and the post-drawing process is 7 pairs of hot rollers, the 7 pairs of hot rollers are GR1 to GR7, and GR4, GR5 and GR6 are shaping rollers;

[0020] The temperature of GR4 is 190-210℃, the temperature of GR5 is 210-220℃, the temperature of GR6 is 220-230℃, and the temperature of GR7 is below 80℃; the speed ratio of GR6 to GR5 is 1.002-1.010, and the speed ratio of GR5 to GR4 is 1.002-1020.

[0021] As a preferred technical solution:

[0022] The method for preparing geotextile polyester industrial yarn as described above provides the following performance indicators for the geotextile polyester industrial yarn: breaking strength ≥ 8.40 cN / dtex, breaking elongation 9.0 ± 0.5%, shrinkage 10 ± 0.5%, and r 5％ ≥56.0%, single spool r 5％ Fluctuation <3.0%, 10 4 Elongation ratio after hours <1.200;

[0023] r 5％ This refers to the strength value (σ) corresponding to a fiber deformation elongation of 5%. 5％ The percentage of the fracture strength (σ) to the total fracture strength;

[0024] Single spool r 5％ Fluctuation refers to a full-bore test performed on a single yarn spool, starting from the yarn head at the outer end of the spool and working inwards to the innermost tail end, measuring all r values. 5％ The maximum fluctuation value;

[0025] 10 4 Elongation ratio after 10 hours refers to the elongation ratio after being placed at room temperature for 10 hours. 4 The ratio of fiber breaking elongation to initial breaking elongation after hours.

[0026] The method for preparing geotextile polyester industrial yarn as described above, wherein the fiber orientation degree of the geotextile polyester industrial yarn is 0.955-0.965, the amorphous region orientation degree is 0.830-0.840, and the crystallinity is 64.0-65.0%.

[0027] The method for preparing geotextile polyester industrial yarn as described above includes the following conditions: GR1 temperature is 60-70℃, GR2 temperature is 90-100℃, GR3 temperature is 125-135℃, GR1 speed is 450-600m / min, the speed ratio of GR2 to GR1 is 1.0-1.1, the speed ratio of GR3 to GR2 is 3.8-4.4, the speed ratio of GR4 to GR3 is 1.2-1.4, and the speed ratio of GR7 to GR6 is 0.98-1.002; the winding tension is 300-350N / 1000D, and the winding speed is 2800-3000m / min.

[0028] In the preparation method of the above-mentioned geotextile polyester industrial yarn, an air-cooling device is provided on the yarn path before winding of GR7 to blow the yarn. The number of air-cooling devices is 1 to 4 sets, and the blowing temperature is 20 to 30°C.

[0029] As described above, in a method for preparing polyester industrial yarn for geosynthetics, the melt is transported from the thickening reactor to the spinning position via a pipeline, the melt temperature is 280-310℃, and the intrinsic viscosity of the melt is >0.950dL / g.

[0030] The principle of this invention is as follows:

[0031] The core problem solved by this invention is how to orient and maintain fiber molecular chain segments to achieve a stable, highly oriented microstructure, thereby achieving the goals of low elongation, high stiffness, and long-term stability.

[0032] First, this invention employs a melt-direct spinning production method. The melt is transported from the thickening reactor to the spinning position via pipelines, eliminating the need for a screw melting process and avoiding the high-temperature, high-shear melting of the polymer during screw melting. During screw melting, shear heat is generated, causing the melt temperature to often exceed the ideal spinning temperature. Furthermore, the rotation of the screw and the strong shear inevitably lead to greater entanglement of the polymer macromolecular chains after melting. Since the pipeline from the screw to the spinning assembly is extremely short, the entangled molecular chain segments cannot be sufficiently relaxed, let alone achieve initial orientation along the flow direction. In contrast, with melt-direct spinning, the total pipeline distance from the thickening reactor outlet to the spinning position is sufficiently long and continuously branched into finer channels. During the flow of the melt through the pipeline and in the static mixer within the pipeline, the entangled molecular chain segments are fully relaxed and "combed," resulting in a certain degree of orientation of the macromolecular chains during the melt stage.

[0033] Secondly, achieving high orientation of fibers under high-speed spinning conditions mainly relies on orientation-induced crystallization during the drawing process. However, excessively rapid or high crystallization leads to numerous physical cross-linking points, hindering the stretching of molecular chain segments and making further orientation difficult, thus preventing the attainment of high orientation. Conversely, insufficient crystallization also results in a lack of fiber stretching points and inadequate stretching. The core technology of this invention lies in controlling crystallization to enhance orientation. Existing technologies neglect the relationship between orientation and crystallization, namely, stress generates orientation, and orientation induces crystallization. In spinning control, the interaction between crystallization and orientation is ignored. High-temperature setting with low setting tension (low speed ratio) causes shrinkage in the amorphous region, resulting in low orientation. Furthermore, excessively rapid crystallization leads to physical cross-linking of crystals, making it difficult to enhance orientation and consequently resulting in a relatively small reduction in elongation at break.

[0034] In the process of this invention, the temperature of the first shaping roller is 190-200°C, close to but below the peak crystallization temperature of PET, controlling the crystallization rate (appropriate crystallinity). Furthermore, the relatively high speed generates significant tension to prevent disorientation of highly oriented amorphous chains. High drawing strengthens the orientation of the low-oriented portions of the amorphous region, increasing overall orientation and achieving synchronous orientation and crystallization. The temperature of the second shaping roller, or a combination of the second and third shaping rollers, is higher (but still lower than in the prior art), aiming to accelerate crystallization. In this stage, the speed ratio is still greater than 1.002, which can suppress the disorientation of amorphous chain segments, allowing this portion of the amorphous chain to crystallize into a stable state. The speed ratio is designed based on the instantaneous maximum internal stress of the orientation structure during deorientation. The instantaneous maximum internal stress refers to the extreme value of internal stress generated when the molecular chain segments thaw and the orientation chain segments deorient after the fiber enters a high-temperature thermal field below the glass transition temperature. The tension (speed ratio of about 1.0020) at which the fiber deformation is about 2% is similar to the instantaneous maximum internal stress of deorientation at the process temperature. At this force value and above, fiber deorientation is suppressed or reorientation is achieved.

[0035] Furthermore, the filaments after setting still carry residual heat. If this heat is not mitigated, it will be carried into the filament cake during high-speed winding, accumulating within the cake. The core temperature of the filament cake will exceed 100°C, which is higher than the glass transition temperature, causing the amorphous regions to disorient. This results in significant fluctuations in elongation and other parameters at different locations inside and outside the filament cake within a single filament roll. In contrast, the rollers before winding, which are non-heated, are kept below 80°C through temperature control. Additionally, the air-cooling device along the winding process increases cooling, reducing residual heat in the filaments. This controls the temperature difference between the inner and outer layers of the filament cake as it falls onto the spool, mitigating disorientation and resulting in more stable elongation and other parameters. Overall, employing a 6- or 7-pair hot drawing process, with 2-3 pairs of setting rollers, also increases the setting time and improves crystallization.

[0036] Beneficial effects:

[0037] (1) A method for preparing geotextile polyester industrial yarn of the present invention has a more stable high orientation in the microstructure of the fiber, and the prepared geotextile polyester industrial yarn has the characteristics of high strength, ultra-low elongation, high stiffness and excellent long-term stability.

[0038] (2) The preparation method of the polyester industrial yarn for geotechnical use of the present invention is based on the modification and process adjustment of existing equipment and production technology, which is easy to implement. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0040] The performance indicators in this invention are tested using the following methods:

[0041] (1) Fracture strength: Tested according to GB / T 16604-2017;

[0042] (2) Elongation at break: Tested according to GB / T 16604-2017;

[0043] (3) Shrinkage rate: Tested according to GB / T 16604-2017;

[0044] (4)r 5％ : refers to the strength value (σ) corresponding to a fiber deformation elongation of 5%. 5％ The percentage of the fracture strength (σ) to the total fracture strength;

[0045] (5) Single spool r 5％ Fluctuation: refers to the measurement of all r values ​​during a full-bore inspection of a single yarn spool, starting from the yarn head at the outer end of the spool and working inwards to the innermost tail end. 5％ The maximum fluctuation value;

[0046] (6)10 4 Elongation ratio after 10 hours: refers to the elongation ratio after 10 hours at room temperature. 4 The ratio of fiber breaking elongation to initial breaking elongation after hours;

[0047] (7) Fiber orientation degree: The orientation degree test method was used for testing;

[0048] (8) Amorphous region orientation: The orientation of the fiber as a whole is obtained by the sound velocity orientation test. Then, the crystallinity and crystalline region orientation are calculated based on the wide-angle X-ray diffraction test results, and the orientation of the amorphous region is deduced.

[0049] (9) Crystallinity: based on wide-angle X-ray diffraction test.

[0050] Example 1

[0051] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0052] (1) PET melt with a temperature of 300℃ and an intrinsic viscosity of 0.966dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0053] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0054] (2) The nascent fibers obtained in step (1) are post-stretched using 6 pairs of hot rollers, the 6 pairs of hot rollers being GR1 to GR6, and GR4 and GR5 being shaping rollers;

[0055] Among them, the temperature of GR1 is 60℃, the temperature of GR2 is 100℃, the temperature of GR3 is 125℃, the temperature of GR4 is 190℃, the temperature of GR5 is 230℃, and the temperature of GR6 is 75℃;

[0056] The speed of GR1 is 650 m / min. The speed ratio of GR2 to GR1 is 1, the speed ratio of GR3 to GR2 is 3.9, the speed ratio of GR4 to GR3 is 1.5, the speed ratio of GR5 to GR4 is 1.002, and the speed ratio of GR6 to GR5 is 1.002.

[0057] (3) After being drawn by 6 pairs of hot rollers, GR6 is equipped with a set of air-cooling device on the wire path before winding to blow the wire. The blowing temperature of the air-cooling device is 25℃.

[0058] (4) Finally, the yarn is wound with a winding tension of 250N / 1000D and a winding speed of 3500m / min to obtain polyester industrial yarn for geotechnical applications.

[0059] The obtained geotextile polyester industrial yarn has a breaking strength of 8.42 cN / dtex, a breaking elongation of 10.9%, a shrinkage rate of 9.2%, and a r 5％ It is 54%, and the single wire spool r 5％ The fluctuation was 2.6%, 10 4 The elongation ratio after hours was 1.254; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.941, the orientation degree of the amorphous region was 0.828, and the crystallinity was 64.3%.

[0060] Example 2

[0061] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0062] (1) PET melt with a temperature of 310℃ and an intrinsic viscosity of 0.97dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0063] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0064] (2) The nascent fibers obtained in step (1) are post-stretched using 6 pairs of hot rollers, the 6 pairs of hot rollers being GR1 to GR6, and GR4 and GR5 being shaping rollers;

[0065] Among them, the temperature of GR1 is 70℃, the temperature of GR2 is 90℃, the temperature of GR3 is 128℃, the temperature of GR4 is 195℃, the temperature of GR5 is 210℃, and the temperature of GR6 is 75℃;

[0066] The speed of GR1 is 500 m / min, the speed ratio of GR2 to GR1 is 1.1, the speed ratio of GR3 to GR2 is 4.5, the speed ratio of GR4 to GR3 is 1.3, the speed ratio of GR5 to GR4 is 1.005, and the speed ratio of GR6 to GR5 is 0.98.

[0067] (3) After being drawn by 6 pairs of hot rollers, GR6 is equipped with 2 sets of air-cooling devices on the wire path before winding to blow the wire. The blowing temperature of each set of air-cooling devices is 25℃ and 20℃ respectively.

[0068] (4) Finally, the yarn is wound with a winding tension of 350N / 1000D and a winding speed of 2800m / min to obtain polyester industrial yarn for geotechnical applications.

[0069] The obtained geotextile polyester industrial yarn has a breaking strength of 8.61 cN / dtex, a breaking elongation of 9.5%, a shrinkage rate of 10.6%, and a r 5％ It is 56.3%, and the single wire spool r 5％ Fluctuation of 2%, 10 4 The elongation ratio after hours was 1.397; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.964, the orientation degree of the amorphous region was 0.835, and the crystallinity was 63.9%.

[0070] Example 3

[0071] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0072] (1) PET melt with a temperature of 290℃ and an intrinsic viscosity of 0.965dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0073] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0074] (2) The nascent fibers obtained in step (1) are post-stretched using 6 pairs of hot rollers, the 6 pairs of hot rollers being GR1 to GR6, and GR4 and GR5 being shaping rollers;

[0075] Among them, the temperature of GR1 is 65℃, the temperature of GR2 is 95℃, the temperature of GR3 is 130℃, the temperature of GR4 is 200℃, the temperature of GR5 is 220℃, and the temperature of GR6 is 75℃;

[0076] The speed of GR1 is 600 m / min, the speed ratio of GR2 to GR1 is 1.05, the speed ratio of GR3 to GR2 is 4.2, the speed ratio of GR4 to GR3 is 1.35, the speed ratio of GR5 to GR4 is 1.01, and the speed ratio of GR6 to GR5 is 1.

[0077] (3) After being drawn by 6 pairs of hot rollers, GR6 is equipped with 3 sets of air-cooling devices on the wire path before winding to blow the wire. The blowing temperature of each set of air-cooling devices is 25℃, 20℃ and 30℃ respectively.

[0078] (4) Finally, the yarn is wound with a winding tension of 280N / 1000D and a winding speed of 3200m / min to obtain polyester industrial yarn for geotechnical applications.

[0079] The obtained geotextile polyester industrial yarn has a breaking strength of 8.47 cN / dtex, a breaking elongation of 10.3%, a shrinkage rate of 9.9%, and a r 5％ It is 54.9%, and the single wire drum r 5％ The fluctuation was 2.3%, 10 4 The elongation ratio after hours was 1.291; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.953, the orientation degree of the amorphous region was 0.826, and the crystallinity was 64.1%.

[0080] Example 4

[0081] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0082] (1) PET melt with a temperature of 280℃ and an intrinsic viscosity of 0.958dL / g is transported from the thickening reactor to the metering pump and spinning assembly through a pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0083] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0084] (2) The nascent fibers obtained in step (1) are post-stretched using 6 pairs of hot rollers, the 6 pairs of hot rollers being GR1 to GR6, and GR4 and GR5 being shaping rollers;

[0085] Among them, the temperature of GR1 is 68℃, the temperature of GR2 is 92℃, the temperature of GR3 is 135℃, the temperature of GR4 is 210℃, the temperature of GR5 is 225℃, and the temperature of GR6 is 70℃;

[0086] The speed of GR1 is 550 m / min, the speed ratio of GR2 to GR1 is 1.08, the speed ratio of GR3 to GR2 is 4, the speed ratio of GR4 to GR3 is 1.4, the speed ratio of GR5 to GR4 is 1.02, and the speed ratio of GR6 to GR5 is 0.99.

[0087] (3) After being drawn by 6 pairs of hot rollers, 4 sets of air-cooling devices are installed on the filament path from GR6 to the winding to blow the filament. The blowing temperature of each set of air-cooling devices is 25℃, 20℃, 30℃ and 28℃ respectively.

[0088] (4) Finally, the yarn is wound with a winding tension of 320N / 1000D and a winding speed of 3000m / min to obtain polyester industrial yarn for geotechnical applications.

[0089] The obtained geotextile polyester industrial yarn has a breaking strength of 8.55 cN / dtex, a breaking elongation of 10.5%, a shrinkage rate of 9.6%, and a r 5％ It is 55.5%, and the single wire spool r 5％ The fluctuation was 2.4%, 10 4 The elongation ratio after hours was 1.316; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.958, the orientation degree of the amorphous region was 0.831, and the crystallinity was 64.8%.

[0090] Example 5

[0091] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0092] (1) PET melt with a temperature of 310℃ and an intrinsic viscosity of 0.968dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0093] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0094] (2) The nascent fibers obtained in step (1) are post-stretched using 7 pairs of hot rollers, the 7 pairs of hot rollers being GR1 to GR7, and GR4, GR5 and GR6 being shaping rollers;

[0095] Among them, the temperature of GR1 is 70℃, the temperature of GR2 is 90℃, the temperature of GR3 is 135℃, the temperature of GR4 is 210℃, the temperature of GR5 is 210℃, the temperature of GR6 is 220℃, and the temperature of GR7 is 75℃.

[0096] The speed of GR1 is 450 m / min. The speed ratio of GR2 to GR1 is 1.09, the speed ratio of GR3 to GR2 is 4.3, the speed ratio of GR4 to GR3 is 1.32, the speed ratio of GR5 to GR4 is 1.006, the speed ratio of GR6 to GR5 is 1.005, and the speed ratio of GR7 to GR6 is 1.002.

[0097] (3) After the 7 pairs of hot rollers are drawn, a set of air-cooling device is installed on the GR7 to the winding path to blow the filament. The blowing temperature of the air-cooling device is 30℃.

[0098] (4) Finally, the yarn is wound with a winding tension of 300N / 1000D and a winding speed of 2800m / min to obtain polyester industrial yarn for geotechnical applications.

[0099] The obtained geotextile polyester industrial yarn has a breaking strength of 8.65 cN / dtex, a breaking elongation of 9.2%, a shrinkage rate of 10.4%, and a r 5％ It is 56.1%, and the single wire spool r 5％ The fluctuation was 2.1%, 10 4 The elongation ratio after hours was 1.171; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.964, the orientation degree of the amorphous region was 0.838, and the crystallinity was 64.7%.

[0100] Example 6

[0101] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0102] (1) PET melt with a temperature of 280℃ and an intrinsic viscosity of 0.959dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0103] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0104] (2) The nascent fibers obtained in step (1) are post-stretched using 7 pairs of hot rollers, the 7 pairs of hot rollers being GR1 to GR7, and GR4, GR5 and GR6 being shaping rollers;

[0105] Among them, the temperature of GR1 is 60℃, the temperature of GR2 is 95℃, the temperature of GR3 is 125℃, the temperature of GR4 is 190℃, the temperature of GR5 is 212℃, the temperature of GR6 is 230℃, and the temperature of GR7 is 74℃.

[0106] The speed of GR1 is 460 m / min. The speed ratio of GR2 to GR1 is 1.05, the speed ratio of GR3 to GR2 is 4.25, the speed ratio of GR4 to GR3 is 1.4, the speed ratio of GR5 to GR4 is 1.01, the speed ratio of GR6 to GR5 is 1.006, and the speed ratio of GR7 to GR6 is 1.

[0107] (3) After the 7 pairs of hot rollers are drawn, the GR7 to the winding path is equipped with 2 sets of air-cooling devices to blow the filament. The blowing temperature of each set of air-cooling devices is 30℃ and 25℃ respectively.

[0108] (4) Finally, the yarn is wound with a winding tension of 350N / 1000D and a winding speed of 2900m / min to obtain polyester industrial yarn for geotechnical applications.

[0109] The obtained geotextile polyester industrial yarn has a breaking strength of 8.7 cN / dtex, a breaking elongation of 9.4%, a shrinkage rate of 10.2%, and a r 5％ It is 56.5%, and the single wire spool r 5％ The fluctuation was 1.8%, 10 4 The elongation ratio after hours was 1.182; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.964, the orientation degree of the amorphous region was 0.836, and the crystallinity was 64.6%.

[0110] Example 7

[0111] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0112] (1) PET melt with a temperature of 290℃ and an intrinsic viscosity of 0.962dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0113] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0114] (2) The nascent fibers obtained in step (1) are post-stretched using 7 pairs of hot rollers, the 7 pairs of hot rollers being GR1 to GR7, and GR4, GR5 and GR6 being shaping rollers;

[0115] Among them, the temperature of GR1 is 68℃, the temperature of GR2 is 98℃, the temperature of GR3 is 130℃, the temperature of GR4 is 205℃, the temperature of GR5 is 215℃, the temperature of GR6 is 225℃, and the temperature of GR7 is 78℃.

[0116] The speed of GR1 is 550 m / min. The speed ratio of GR2 to GR1 is 1.02, the speed ratio of GR3 to GR2 is 4, the speed ratio of GR4 to GR3 is 1.31, the speed ratio of GR5 to GR4 is 1.008, the speed ratio of GR6 to GR5 is 1.01, and the speed ratio of GR7 to GR6 is 0.99.

[0117] (3) After the 7 pairs of hot rollers are drawn, the 3 sets of air-cooling devices installed on the GR7 to the winding path blow the filament. The blowing temperatures of each set of air-cooling devices are 30℃, 25℃ and 20℃ respectively.

[0118] (4) Finally, the yarn is wound with a winding tension of 320N / 1000D and a winding speed of 2940m / min to obtain polyester industrial yarn for geotechnical applications.

[0119] The obtained geotextile polyester industrial yarn has a breaking strength of 8.62 cN / dtex, a breaking elongation of 9.3%, a shrinkage rate of 10.1%, and a r 5％ It is 56.6%, and the single wire spool r 5％ The fluctuation was 1.9%, 10 4 The elongation ratio after hours was 1.18; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.962, the orientation degree of the amorphous region was 0.835, and the crystallinity was 64.5%.

[0120] Example 8

[0121] A method for preparing polyester industrial yarn for geosynthetic applications, using melt spinning, comprises the following steps:

[0122] (1) PET melt with a temperature of 300℃ and an intrinsic viscosity of 0.964dL / g is transported from the thickening kettle to the metering pump and spinning assembly through the pipeline. The melt is sprayed out from the spinneret to form nascent fibers, which are then bundled to the GR1 roller.

[0123] Among them, the component filter screen specification is 25 microns, the side blowing air pressure is 800Pa, the side blowing air temperature is 20℃, the side blowing air velocity is 0.8m / s, the post-heating temperature is 300℃, and the spinning oil concentration is 18%.

[0124] (2) The nascent fibers obtained in step (1) are post-stretched using 7 pairs of hot rollers, the 7 pairs of hot rollers being GR1 to GR7, and GR4, GR5 and GR6 being shaping rollers;

[0125] Among them, the temperature of GR1 is 65℃, the temperature of GR2 is 100℃, the temperature of GR3 is 132℃, the temperature of GR4 is 200℃, the temperature of GR5 is 220℃, the temperature of GR6 is 228℃, and the temperature of GR7 is 76℃.

[0126] The speed of GR1 is 600 m / min. The speed ratio of GR2 to GR1 is 1, the speed ratio of GR3 to GR2 is 4.1, the speed ratio of GR4 to GR3 is 1.24, the speed ratio of GR5 to GR4 is 1.002, the speed ratio of GR6 to GR5 is 1.002, and the speed ratio of GR7 to GR6 is 0.98.

[0127] (3) After the 7 pairs of hot rollers are drawn, the 4 sets of air-cooling devices installed on the GR7 to the winding path blow the filament. The blowing temperature of each set of air-cooling devices is 30℃, 25℃, 20℃ and 28℃ respectively.

[0128] (4) Finally, the yarn is wound with a winding tension of 340N / 1000D and a winding speed of 3000m / min to obtain polyester industrial yarn for geotechnical applications.

[0129] The obtained geotextile polyester industrial yarn has a breaking strength of 8.73 cN / dtex, a breaking elongation of 9.5%, a shrinkage rate of 10.1%, and a r 5％ It is 56.3%, and the single wire spool r 5％ The fluctuation was 1.7%, 10 4 The elongation ratio after hours was 1.083; the fiber orientation degree of the polyester industrial yarn for geotextiles was 0.96, the orientation degree of the amorphous region was 0.833, and the crystallinity was 64.5%.

Claims

1. A method for preparing polyester industrial yarn for geotextile applications, characterized in that: The production method is melt spinning, and the post-drawing process is 6 pairs of hot rollers, which are GR1 to GR6, and GR4 and GR5 are setting rollers. The temperature of GR4 is 190–210℃, the temperature of GR5 is 210–230℃, and the temperature of GR6 is below 80℃; the speed ratio of GR5 to GR4 is 1.002–1.020; The performance indicators of polyester industrial yarn for geosynthetic applications are: breaking strength ≥ 8.20 cN / dtex, breaking elongation 10.0 ± 1.0%, shrinkage 10 ± 1.5%, and r. 5％ ≥50.0%, single spool r 5％ Fluctuation <3.0%, 10 4 Elongation ratio after hours <1.400; r 5％ It refers to the percentage of the breaking strength corresponding to a fiber deformation elongation of 5%. Single spool r 5％ Fluctuation refers to a full-bore test performed on a single yarn spool, starting from the yarn head at the outer end of the spool and working inwards to the innermost tail end, measuring all r values. 5％ The maximum fluctuation value; 10 4 Elongation ratio after 10 hours refers to the elongation ratio after being placed at room temperature for 10 hours. 4 The ratio of fiber breaking elongation to initial breaking elongation after hours; The fiber orientation degree of the polyester industrial yarn for geotextiles is 0.935–0.965, the orientation degree of the amorphous region is 0.820–0.840, and the crystallinity is 62.0–65.0%.

2. The method for preparing a geotextile polyester industrial yarn according to claim 1, characterized in that, The temperature of GR1 is 60-70℃, the temperature of GR2 is 90-100℃, the temperature of GR3 is 125-135℃, the speed of GR1 is 500-650m / min, the speed ratio of GR2 to GR1 is 1.0-1.1, the speed ratio of GR3 to GR2 is 3.9-4.5, the speed ratio of GR4 to GR3 is 1.3-1.5, and the speed ratio of GR6 to GR5 is 0.98-1.002; the winding tension is 250-350N / 1000D, and the winding speed is 2800-3500m / min.

3. The method for preparing a geotextile polyester industrial yarn according to claim 2, characterized in that, The GR6 is equipped with an air-cooling device on the yarn path before winding to blow the yarn. The number of air-cooling devices is 1 to 4 sets, and the blowing temperature is 20 to 30℃.

4. A method for preparing polyester industrial yarn for geotextile applications, characterized in that: The production method is melt spinning, and the post-drawing process is 7 pairs of hot rollers. The 7 pairs of hot rollers are GR1 to GR7, and GR4, GR5 and GR6 are setting rollers. The temperature of GR4 is 190-210℃, the temperature of GR5 is 210-220℃, the temperature of GR6 is 220-230℃, and the temperature of GR7 is below 80℃; the speed ratio of GR6 to GR5 is 1.002-1.010, and the speed ratio of GR5 to GR4 is 1.002-1020; The performance indicators of polyester industrial yarn for geosynthetic applications are: breaking strength ≥ 8.40 cN / dtex, breaking elongation 9.0 ± 0.5%, shrinkage 10 ± 0.5%, and r. 5％ ≥56.0%, single spool r 5％ Fluctuation <3.0%, 10 4 Elongation ratio after hours <1.200; r 5％ It refers to the percentage of the breaking strength corresponding to a fiber deformation elongation of 5%. Single spool r 5％ Fluctuation refers to a full-bore test performed on a single yarn spool, starting from the yarn head at the outer end of the spool and working inwards to the innermost tail end, measuring all r values. 5％ The maximum fluctuation value; 10 4 Elongation ratio after 10 hours refers to the elongation ratio after being placed at room temperature for 10 hours. 4 The ratio of fiber breaking elongation to initial breaking elongation after hours; The fiber orientation degree of the polyester industrial yarn for geotextiles is 0.955–0.965, the orientation degree of the amorphous region is 0.830–0.840, and the crystallinity is 64.0–65.0%.

5. The method for preparing a geotextile polyester industrial yarn according to claim 4, characterized in that, The temperature of GR1 is 60-70℃, the temperature of GR2 is 90-100℃, the temperature of GR3 is 125-135℃, the speed of GR1 is 450-600m / min, the speed ratio of GR2 to GR1 is 1.0-1.1, the speed ratio of GR3 to GR2 is 3.8-4.4, the speed ratio of GR4 to GR3 is 1.2-1.4, and the speed ratio of GR7 to GR6 is 0.98-1.002; the winding tension is 300-350N / 1000D, and the winding speed is 2800-3000m / min.

6. The method for preparing a geotextile polyester industrial yarn according to claim 5, characterized in that, The GR7 is equipped with an air-cooling device on the yarn path before winding to blow the yarn. The number of air-cooling devices is 1 to 4 sets, and the blowing temperature is 20 to 30℃.

7. A method for preparing geotextile polyester industrial yarn according to claim 1 or 4, characterized in that, The melt is transported from the thickening reactor to the spinning position via pipeline. The melt temperature is 280-310℃ and the intrinsic viscosity of the melt is >0.950dL / g.