Method for producing polyester industrial yarn by one-step method

A polyester industrial yarn and footwork technology, which is applied in the field of polyester industrial yarn, can solve the problems of high strength, high modulus and low shrinkage rate, the product cannot reach high modulus, and low shrinkage can not be taken into account, and achieve high modulus, low shrinkage, etc. Improve the uniformity of viscosity and improve the effect of dry crystallization

Inactive Publication Date: 2010-03-17

SHANDONG HELON POLYTEX CHEM FIBER

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AI-Extracted Technical Summary

Problems solved by technology

Among them, the one-step method has the advantages of short process flow, high product quality, good benefit and less equipment footprint, so it is better than the two-step method, but the high-temperature spinning, high-temperature and high-stretching spinning process not only affects the performance of the equipment. Very high requirements, such as spinning speed at least 6000 ~ 7000m/min, and because the stretching heat setting is carried out at a higher speed, the heating time of the tow is short...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Method used

As can be seen from the above analysis, when the high-strength, high-modulus and low-shrinkage polyester industrial yarn is produced by the high-speed one-step process, each process process control should be optimized, and suitable process conditions are selected to ensure that high spinning speed and stable spinning process are reached, In high-stretching and heat setting, the fiber-forming polyester polymer has high crystallinity, high degree of orientation and low internal residual stress. Among them, the quality of raw material slices is very critical, because high-speed spinning and high-stretching not only require high viscosity and high purity of the spinning melt, but also require uniform viscosity; secondly, reasonably control the temperature of the stretching process and the various stages of stretching. Stretch ratio to ensure high strength, high modulus and low shrinkage of finished yarn in reasonable stretching and heat setting.

Drying and pre-crystallization of the present invention adopt continuous crystallization drier, and the drying bed of continuous crystallization drier is provided with numerous vertical or obliquely distributed drying gas ventilation holes, and the airflow blown from the ventilation holes makes the PET chips On the drying bed, it moves evenly towards the discharge direction. There is a baffle in the air duct of the continuous crystallization dryer to adjust the air volume of the drying gas to control the drying temperature and time of the PET chips. The continuous crystallization shortens the process flow. The dry crystallization effect is improved, so that the moisture content of the raw material PET chips is less than or equal to 20ppm, and the crystallinity can reach more than 40% within 40±2 minutes of pre-crystallization.

Spinning speed is an important factor controlling the degree of orientation of the as-spun filament, and the size of the degree of orientation affects the rear draw ratio. For the spinning melt of high-viscosity slices, if the fine stream immediately goes out of the spinneret If it is cooled, the tensile stress of the spinneret stretching will rise sharply, the pre-orientation degree of the filament will increase rapidly, and a "skin-core structure" may be formed in the fiber, resulting in difficulty in stretching. In the present invention, a heating device is installed at the lower part of the spinning box, and the cooling air volume and temperature can be adjusted according to different varieties, and the cooling air blown out by the side blowing device with a honeycomb structure can be moderated and uniform, and the freezing point of the filaments can be moved down by 50~ 100cm, so that the yarn obtains a lower degree of pre-orientation, which ensures that the yarn is suitable for further high-speed and high-magnification stretching.

The solid-phase thickening of the present invention adopts two continuous polymerization reactors in series, and the PET chips flow through the two polymerization reactors successively, and flow through in the form of plug flow, preventing the slices from breaking in the rea...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Abstract

The invention discloses a method for producing polyester industrial yarn by a one-step method, comprising a solid-phase polymerization step, a fusing spinning step, a stretching and heat shaping stepand a winding and forming step. The method is characterized in that: in the solid-phase polymerization step, raw materials with the viscosity of 0.65+/-0.05dl/g, the content of terminal carboxyl groupof 24+/-3mol/t are cut into pieces and stuck to be materials with the viscosity of 1.035+/-0.01dl/g, the water content less than or equal to 20ppm and the content of the terminal carboxyl group lessthan or equal to 15mol/t through continuous solid-phase polymerization; in the fusing spinning step, the ratio of the length to the diameter of spinneret orifices of a spinneret plate for spinning is3:1, the deviation ratio of the aperture to the length of the spinneret orifice is +/-0.02, and the spinneret orifices are evenly arrayed in the spinneret plate; in the stretching and heat shaping step, four rollers are adopted for stretching and shaping; and in the winding and forming step, the winding speed is 6,300+/-500m/min. The polyester industrial yarn can simultaneously achieve the performances of high strength, high modulus and low shrinkage, and has breakage strength more than or equal to 8.2CN/dtex, initial modulus more than or equal to 110N/dtex, the modulus more than or equal to 5.0cn/dtex when 5 percent is stretched and dry heat shrinking percentage less than or equal to 4.1 percent.

Application Domain

Spinning head liquid feederMelt spinning methods

Technology Topic

Water contentSolid phases +14

Examples

Experimental program(3)

Example Embodiment

[0023] Example 1

[0024] Production variety 1: High-strength, high-modulus, low-shrinkage polyester industrial filament 1100dtex 103G:

[0025] Raw material PET chip properties: viscosity 0.60dl/g, terminal carboxyl group content 26.8mol/t

[0026] After continuous solid-phase polymerization, chip properties: viscosity 1.034dl/g terminal carboxyl group content 14.9mol/t water content 19.5ppm

[0027] The thickened PET chips are melted and extruded by a screw extruder. The process of the screw extruder:

[0028] The temperature of the five heating zones of the screw is: Zone 1: 300 Zone 2: 300 Zone 3: 296 Zone 4: 298 Zone: 299

[0029] Screw pressure: 14.8Mpa

[0030] Using one-step spinning, four-roller stretching and shaping process:

[0031] The first roller group: temperature 95℃, speed 2200m/min;

[0032] The second roller group: temperature 180℃, speed 5000m/min;

[0033] The third roller group: temperature 240℃, speed 6250m/min;

[0034] The fourth roller set: the temperature is 145°C, the speed is 6150m/min.

[0035] Winding speed: 6000m/min.

Example Embodiment

[0036] Example 2

[0037] Production variety 2: High-strength, high-modulus, low-shrinkage polyester industrial filament 1670dtex 303G:

[0038] Raw material PET chip properties: viscosity 0.65dl/g, terminal carboxyl group content 25.5mol/t

[0039] After continuous solid-phase polymerization, chip properties: viscosity 1.035dl/g terminal carboxyl group content 14.7mol/t water content 19.5ppm

[0040] The thickened PET chips are melted and extruded by a screw extruder. The process of the screw extruder:

[0041] The temperature of the five heating zones of the screw are as follows: Zone 1: 302 Zone 302: Zone 302: Zone 298: Zone 4: 299 Zone: 300

[0042] Screw pressure: 16.0Mpa

[0043] Using one-step spinning, four-roller stretching and shaping process:

[0044] The first roller group: temperature 100℃, speed 2600m/min;

[0045] The second roller set: temperature 185℃, speed 5350m/min;

[0046] The third roller group: temperature 245℃, speed 6550m/min;

[0047] The fourth roller set: the temperature is 145°C, the speed is 6400m/min.

[0048] Winding speed: 6300m/min.

Example Embodiment

[0049] Example 3

[0050] Production variety 3: High-strength, high-modulus, low-shrinkage polyester industrial filament 1440dtex 202G

[0051] Raw material PET chip properties: viscosity 0.69dl/g, terminal carboxyl group content 21.2mol/t

[0052] After continuous solid-phase polymerization, chip properties: viscosity 1.036dl/g terminal carboxyl group content 14.5mol/t water content 19.2ppm

[0053] The thickened PET chips are melted and extruded by a screw extruder. The process of the screw extruder:

[0054] The temperature of the five heating zones of the screw are: Zone 1: 304 Zone 2: 304 Zone 3: 300 Zone 4: 300 Zone 5: 301

[0055] Screw pressure: 16.2Mpa

[0056] Using one-step spinning, four-roller stretching and shaping process:

[0057] The first roller group: temperature 108℃, speed 3000m/min;

[0058] The second roller group: temperature 195℃, speed 5800m/min;

[0059] The third roller group: temperature 255℃, speed 7050m/min;

[0060] The fourth roller set: the temperature is 155℃, the speed is 6900m/min.

[0061] Winding speed: 6800m/min.

[0062] The performance indexes of the high-strength, high-modulus and low-shrinkage industrial yarn prepared in the above embodiments are shown in Table 1:

[0063] Item

[0064] The high strength, high initial modulus and low shrinkage mechanical properties of the high-strength, high-modulus, low-shrinkage polyester industrial yarn are due to the high crystallinity, orientation and low internal residual stress of the fiber-forming polyester polymer. High crystallinity and high orientation are achieved through high-speed spinning and relatively high drawing speed. However, in actual production, when the spinning speed and drawing speed are high, not only the equipment performance and the quality performance of the raw material PET chips are higher, but also the process control is difficult, and the spinning process is unstable. At a higher speed, the heating time of the tow is shorter, and the crystal growth is insufficient, which affects the crystallinity of the polymer, so the low shrinkage performance of the silk cannot be taken into account.

[0065] From the above analysis, it can be seen that when high-strength, high-modulus, low-shrinkage polyester industrial yarn is produced by the high-speed one-step process, the process control of each process should be optimized, and appropriate process conditions should be selected to ensure high spinning speed and stable spinning process. In stretching and heat setting, the fiber-forming polyester polymer has high crystallinity, high orientation and low internal residual stress. Among them, the quality of the raw material slices is very important, because high-speed spinning and high-power stretching not only require high viscosity and high purity of the spinning melt, but also require uniform viscosity; secondly, the temperature of the stretching process and the various levels of stretching are reasonably controlled. The stretch ratio is to ensure the high-strength, high-modulus and low-shrinkage performance of the finished wire in reasonable stretching and heat setting.

[0066] The drying and pre-crystallization of the present invention adopt a continuous crystallization dryer. The drying bed of the continuous crystallization dryer is provided with numerous drying gas vents distributed vertically or diagonally. The air flow blown from the vents makes the PET slices on the drying bed. Evenly move to the discharge direction. The air duct of the continuous crystallization dryer is equipped with a baffle to adjust the air volume of the drying gas to control the drying temperature and time of the PET chips. The continuous crystallization shortens the process flow and improves the drying. The crystallization effect makes the pre-crystallization within 40±2min, the moisture content of the raw material PET chip is ≤20ppm, and the crystallinity can reach more than 40%.

[0067] The solid-phase thickening of the present invention adopts two continuous polymerization reactors connected in series, and the PET chips flow through the two polymerization reactors in sequence and flow through in the form of plug flow, which prevents the back mixing phenomenon of the chips in the reactor. It not only increases the polymerization reaction time, but also increases the uniformity of the reaction, thus improving the uniformity of the viscosity of the PET chips after the polymerization reaction. The reaction uses high-purity nitrogen to heat, avoiding the phenomenon of oxidative degradation, and taking away the reaction Molecular substances improve the purity of the slices, thereby ensuring the stability of high-speed spinning. Due to the improved polymerization effect, the present invention adopts domestic ordinary PET chips through the solid phase thickening process of the present invention, the viscosity of the chips can reach 1.036dl/g, the viscosity fluctuation is controlled within 0.01dl/g, and the terminal carboxyl group content is ≤15mol /t, it can fully meet the requirements of high viscosity, high purity and viscosity uniformity of the chips during high-speed spinning of high-strength, high-modulus, low-shrinkage polyester industrial yarn.

[0068] When high-viscosity chips are melted and extruded, the temperature setting must fully consider the high temperature caused by the shear force of the screw extruder on the high-viscosity melt. The screw extruder used in the present invention is divided into five zones for heating. The temperature of the first three zones is controlled mainly according to the characteristics of the slices and the amount of slices fed. When the temperature is too high, the premature melting of the slices will easily increase the thermal degradation of the polyester. If the temperature is too low, the melt cannot be extruded well, and it may even cause uneven mixing of the melt and surge of the extruder. The temperature of the latter two zones is mainly determined by the spinning temperature and can be used for adjustment. The intrinsic viscosity of the melt. The screw temperature of the present invention is set at 300±5°C, and the biphenyl temperature setting range is 305±5°C. In order to ensure that the melt is evenly distributed at each spinning position and there is a constant pressure before the metering pump, the extruder outlet pressure must be set, especially for the high-strength, high-modulus, low-shrinkage polyester industrial yarn, due to its high melt viscosity and flow resistance The extrusion pressure is higher than that of ordinary industrial yarn. The screw extrusion pressure of the present invention is 16±2Mpa.

[0069] In the production process of the present invention, from the start of pre-crystallization to the entrance of the screw extruder, nitrogen has been used to protect the slices and spinning melt during polymerization, avoiding the risk of polyester polymer in the raw materials and melt. Oxidative degradation phenomenon.

[0070] When high-viscosity chips are used for high-speed spinning, due to the high viscosity of the melt, the flow resistance is large, and when the melt is ejected from the spinneret of the spinneret during high-speed spinning, the ejection speed is high, and the shear speed is also high. , So there are special requirements for the structure of the spinneret. In the spinneret of the present invention, the length-to-diameter ratio of the spinneret holes is appropriately enlarged, and the manufacturing precision is high. The spinneret holes are evenly arranged on the spinneret, which ensures the requirements for melt flow performance during high-speed spinning and the filament Consistency and uniformity during spinning.

[0071] Spinning speed is an important factor to control the pre-orientation degree of the nascent yarn, and the size of the pre-orientation degree affects the post-drawing ratio. For the spinning melt of high-viscosity chips, if it is cooled immediately after the trickle exits the spinneret, The tensile stress of the spinneret will rise sharply, the pre-orientation degree of the thread will increase quickly, and a "skin-core structure" may be formed in the fiber, causing difficulty in stretching. In the present invention, a heating device is installed at the lower part of the spinning box body, which can adjust the cooling air volume and temperature according to different varieties, and the side blowing device with a honeycomb structure makes the cooling air blown out evenly, and the solidification point of the thread can be moved down by 50~ 100cm, the thread has a low degree of pre-orientation, which ensures that the thread is suitable for further high-speed and high-power stretching.

[0072] The polyester spun yarn spun with high-viscosity chips generally has a higher degree of pre-orientation than conventional polyester yarns, and its tensile yield stress is also larger, the deformation is slow, and it is difficult to complete one-time stretching, so multi-stage stretching is used. The traditional polyester industrial yarn production process generally uses more than 5 sets of rollers for stretching and setting. The disadvantage of this process is due to the larger recovery setting. While reducing heat shrinkage, the fiber modulus is also significantly reduced. Affected the use of subsequent procedures. The present invention adopts a 4-roll stretching and setting process. Between the first and second roll sets is a pre-draft zone, between the second and third roll sets is a continuous stretching zone, and between the third and fourth roll sets is In the relaxation setting zone, the total stretching ratio is controlled at 2.5-3.5. Due to the use of two-stage stretching, the uniformity of stretching and the strength of the fiber are improved. After high-stretching, gentle relaxation and heat setting are adopted, so that the finished yarn can maintain high strength, high modulus, low shrinkage and low fixed elongation. Coordination.

[0073] Because the present invention adopts the above series of optimized production processes, firstly it ensures the melt quality suitable for high-speed spinning and a stable spinning process. Secondly, a reasonable drawing ratio is selected and the one-step high-speed spinning process is used to spin winding. The speed can reach 6800m/min, and the produced polyester industrial yarn can achieve high strength, high modulus and low shrinkage at the same time. Its breaking strength is 1~1.5CN/dtex higher than conventional high modulus and low shrinkage polyester industrial filament, and its initial modulus is higher than conventional The modulus low shrinkage polyester industrial filament is increased by 10-15CN/dtex.

[0074] The high-strength, high-modulus, low-shrinkage polyester industrial yarn produced by the invention can be used for tire cord fabrics of high-grade passenger tires and other rubber framework materials.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

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PUM

Property	Measurement	Unit
Breaking strength	>= 8.2	cN/dtex
Initial modulus	>= 110.0	cN/dtex
Modulus	>= 5.0	cN/dtex
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

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Method for producing polyester industrial yarn by one-step method

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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