A kind of polyester ITY yarn and production method thereof

Abstract

The present application discloses a polyester ITY filament and a production method thereof. In this method, the polyester melt is extruded from a spinning pack under the control of two groups of metering pump frequency converters, and polyester monofilaments are obtained after cooling. Part of the polyester monofilaments are oiled on an oil nozzle, drawn and shaped through GR0 and a hot roll box to form FDY filaments, and another part of the polyester monofilaments are oiled to form POY filaments; the FDY filaments and the POY filaments are mixed in a pre-networker through GR1 for pre-networking, then enter a main networker through GR2 for main networking, and finally enter a winding machine through GR3 for winding to obtain ITY filaments; before entering the pre-networker, the tension of the FDY filaments is 10-14 cN, the tension of the POY filaments is 12-16 cN, and the tension of the FDY filaments is less than that of the POY filaments, and the tension difference is 1-2 cN. The present application uses conventional FDY production equipment and adopts a one-step method to prepare a super cotton-like ITY conjugate filament with good moisture permeability and air permeability.

Description

Technical Field

[0001] The present application relates to the field of polyester spinning, and in particular to a polyester ITY yarn and a production method thereof. Background Art

[0002] At present, textile enterprises are facing the situation of shortage of cotton resources and high prices. The chemical fiber industry is actively looking for super-imitation cotton fibers that can replace cotton. This type of super-imitation cotton fiber uses modification technology to transform the structure of conventional polyester, so that the modified polyester fiber not only imitates cotton in feel, appearance and performance, but also exceeds cotton in function. Fabrics made of super-imitation cotton fibers reach or exceed cotton fabrics in terms of vision, touch, comfort and functionality.

[0003] The cross section of cotton fiber is irregular waist-shaped with a central cavity structure. The fiber is flat and ribbon-shaped in the longitudinal direction, with a spiral twist, which is called "natural twist". It is naturally formed during the growth of cotton fiber, and the modulus of cotton fiber is small. These characteristics make it fluffy and soft. However, polyester fiber contains benzene rings, which cannot rotate inward, and the molecular chain segment is relatively rigid, so it feels hard. The super-imitation cotton polyester varieties currently being tackled mainly use modification technology. One type is to improve the matte modification of fiber senses to achieve cotton-like appearance; the other type is functional addition modification to achieve cotton-like performance. Among them, the matte modification for fiber senses can be achieved by relying on polyester copolymerization or blending addition. For example, the "polyester super-imitation cotton popular fabric" product developed in Europe, the United States and Japan has the main technical feature of using high-concentration Ti02 masterbatch for blending spinning to obtain a cotton-like fabric with a soft gloss visual effect. The modification of fiber properties mostly uses methods such as hydrophilic grafting and special-shaped cross-sections to make the surface of cotton-imitation polyester fibers obtain moisture absorption and breathability similar to cotton fibers. However, this type of modification method is too complicated, and the equipment modification and production costs are high. Summary of the invention

[0004] The present application provides a polyester ITY yarn and a production method thereof, which can utilize existing FDY equipment to realize the production of super-cotton-like polyester ITY yarn.

[0005] In the first aspect, the present application provides a method for producing polyester ITY yarn:

[0006] The polyester melt is extruded from the spinning assembly under the control of two groups of metering pump frequency converters, and the polyester monofilament is obtained after cooling and forming. The polyester monofilament extruded by one metering pump frequency converter is oiled by the oil nozzle, stretched and shaped by the GR0 godet, and drawn by the hot roller box to form FDY yarn. The polyester monofilament extruded by another metering pump frequency converter is oiled to form POY yarn. The FDY yarn is mixed with the POY yarn in the pre-netting device through the GR1 godet, and pre-netted, and then enters the main netting device through the GR2 godet for main netting, and finally enters the winder through the GR3 godet for winding to obtain ITY yarn.

[0007] Before entering the pre-network device, the tension of the FDY yarn is 10-14 cN, the tension of the POY yarn is 12-16 cN, and the tension of the FDY yarn is less than that of the POY yarn, with a tension difference of 1-2 cN.

[0008] This application utilizes the existing FDY equipment, by adding a set of metering pump frequency converters, to simultaneously produce low-shrinkage FDY yarns and high-shrinkage POY yarns, and prepare ITY blended fibers in one step. Compared with POY yarns, FDY yarns are stretched and heat-set, and their orientation and crystallinity are higher, and their shrinkage is lower. When the ITY yarn is dyed and finished at high temperature, a curled structure of FDY spirally wrapped around POY yarn is formed due to the large difference in shrinkage between the two. This curled structure allows the ITY yarn to form a velvet loop in the length direction, increase the gaps in the silk thread, and have a high fluffiness, with good air permeability, moisture permeability and other cotton-like effects.

[0009] It is worth noting that in the traditional pre-networking process, the tension of FDY yarn and POY yarn should be as uniform as possible, so that the two fibers are evenly intertwined and entangled, and the uniform formation of network points is promoted to improve the breaking strength and breaking elongation of the mixed fiber. However, the present application controls the tension of the yarn before entering the pre-networking device, so that the tension of the FDY yarn is less than the tension of the POY yarn to form a tension difference, and the FDY yarn is more relaxed, so that the FDY yarn can be wound on the POY yarn under the air pressure of the pre-networking device, and a certain spiral curling structure is pre-formed, so that in the subsequent dyeing and finishing process, the ITY yarn is induced to form a finer velvet loop structure, improve its fluffiness and feel, and improve its moisture permeability, breathability and other cotton-like effects. It should be noted that when the tension difference is too small, the FDY yarn and the POY yarn cannot form a good spiral winding, and the promotion effect is not obvious; when the tension difference is too large, the distribution of the FDY yarn and the POY yarn inside the ITY yarn will be locally concentrated. This uneven distribution will reduce the cohesion between the mixed fiber yarns, thereby reducing the strength performance; and the subsequently formed velvet loop structure will also be reduced, affecting the cotton-like effect.

[0010] In addition, if the tension of the FDY yarn is too small or the tension of the POY yarn is too large before the pre-network, it is easy to cause unstable production or even impossible production. The reason is that when the tension of the FDY yarn before the pre-network is too small, the yarn bundle shakes too much during the spinning process, and the two adjacent yarn bundles are easy to merge or collide, and the contact area between the yarn bundle and the hot roller is inconsistent, which will cause unstable production such as broken yarn under high-speed spinning. When the tension of the POY yarn before the pre-network is too large, it is easy to cause POY broken yarn.

[0011] In any of the above technical solutions, the cooling adopts ring air cooling.

[0012] In any of the above technical schemes, the spinning temperature is 286-290°C, the cooling air temperature is 20.5±1°C, the pressure of the pre-network device is 1-3 bar, and the pressure of the main network device is 4-6 bar; the rotation speed of the wire guide disc GR0 is 800-1100 m / min, the rotation speed of the wire guide disc GR1 is 2930-3300 m / min, the rotation speed of the wire guide disc GR2 is 2940-3320 m / min, the rotation speed of the wire guide disc GR3 is 2930-3300 m / min, and the winding speed is 2970-3300 m / min; the speed difference between the wire guide disc GR1 and the wire guide disc GR2 is 10-20 m / min.

[0013] Before entering the pre-network device, the tension of the FDY yarn depends on the speed difference between GR1 and GR2. The greater the speed difference, the greater the tension; while the tension of the POY yarn depends on the speed of GR2. The greater its speed, the greater the tension. Based on this, the present application sets the speed of GR2 to be greater than that of the wire guide GR1, and the speed difference between GR1 and GR2 is in the range of 10 to 20 m / min, which can achieve the control of its target tension difference. It should be noted that the yarn tension before the pre-network device can be measured using a spinning tension meter. During the measurement, for FDY yarn, the tension of the yarn between GR1 and the pre-network device should be measured; for POY yarn, the tension of the yarn between the tunnel mouth and the pre-network device should be measured.

[0014] In any of the above technical solutions, the spinning assembly is a DIO dual-channel assembly, which has a spinneret, and the spinnerets on the spinneret are arranged in concentric circles; the spinneret is provided with a first ventilation slot, a second ventilation slot and a third ventilation slot in parallel, and the spinnerets are symmetrically distributed around the first ventilation slot as the central axis, and the second ventilation slot and the third ventilation slot respectively divide the spinnerets located on both sides of the first ventilation slot into two parts of the same number.

[0015] In any of the above technical solutions, the widths of the first ventilation slot, the second ventilation slot and the third ventilation slot are all 7 to 8 mm.

[0016] Preferably, the widths of the first ventilation slot, the second ventilation slot and the third ventilation slot are all 7.5 mm.

[0017] This application designs and applies a three-slot spinneret, which effectively improves the penetration of cooling air into the tow, making the cooling of the tow from the center to the outer layer more uniform, reducing the phenomenon of floating and fuzzy fibers. At the same time, it effectively avoids the turbulent vibration of the filaments caused by the ring blowing effect, reduces the collision and friction between the tow and the hot roller, wire guide and other equipment components, thereby reducing the generation of fiber fuzz and broken ends. In addition, more uniform cooling makes the crystallization and molecular chain orientation of the tow more regular, which is conducive to improving its strength and other mechanical properties.

[0018] In any of the above technical solutions, the oil content of the polyester ITY yarn is 0.50±0.1%.

[0019] In any of the above technical solutions, the oil content of the POY yarn is 0.40±0.05%, and the oil content of the FDY yarn is 0.62±0.1%.

[0020] Super-cotton-like ITY yarn usually needs to be false-twisted and stretched to increase the elasticity and fluffiness of the fiber and other cotton-like characteristics. If the oil content of ITY yarn is too high, on the one hand, it will affect the false twist effect and cause uneven twist distribution; on the other hand, the oil agent is easy to accumulate in the rollers, false twisters and hot boxes, shortening the downtime cleaning cycle, affecting production efficiency and processing quality. Therefore, the oil content of super-cotton-like ITY yarn needs to be much lower than that of conventional ITY products (the oil content of conventional products is 0.80±0.1%, and the oil content of super-cotton-like products is required to be 0.50±0.1%).

[0021] However, it should be noted that in order to achieve a decrease in the total oil content of mixed fiber yarns, the oil content of FDY yarns and POY yarns should not be reduced year-on-year (the oil content of conventional FDY yarns is 0.8-1.1wt%, and the oil content of conventional POY yarns is 0.35±0.1%), which may easily increase the friction between POY yarns and the porcelain parts of the winding equipment, resulting in floating and hairy yarns. In addition, due to the low orientation and crystallinity of POY yarns, if the oil content of POY yarns is reduced, the high-speed friction between the yarn and the porcelain parts of the winding equipment at high spinning speeds will produce a large temperature rise, resulting in local unexpected crystallization of POY yarns, inconsistent crystallinity of each section of the yarn, and reduced shrinkage of ITY yarns, affecting their cotton-like effect and strength properties. To overcome this problem, the present application can control the oil supply of POY yarn by adding a group of oil pumps to the existing equipment and using an independent frequency converter to ensure the oil content of POY fiber. In this way, the oil content of FDY yarn can be reduced alone, and the total oil content of ITY blended yarn can be reduced, thereby meeting the production needs of imitation cotton blended yarn.

[0022] It should be noted that the oil content of this application refers to the percentage of the mass of the oil agent in the tow to the total mass of the tow, and is measured with reference to FZ / T 54118-2019 "High Shrinkage Polyester Drawn Yarn / Polyester Pre-Oriented Yarn Blended Yarn". When the oil content of POY yarn is 0.40±0.05% and the oil content of FDY yarn is 0.62±0.1%, the requirement of ITY yarn oil content of 0.50±0.1% can be met, and the ITY yarn obtained has the least hair content. Increasing or decreasing the oil content of either POY yarn or FDY yarn will lead to an increase in its hair content.

[0023] In any of the above technical solutions, the FDY yarn is oiled with a diluent oil having an oil content of 60 to 70 wt%, and the POY yarn is oiled with a diluent oil having an oil content of 10 to 20 wt%.

[0024] For example, the oil used for the FDY yarn is TK-1009, and the oil temperature is controlled at 30-35°C; the oil used for the POY yarn is TK-3588, and the oil temperature is controlled at 30-35°C.

[0025] The emulsion is prepared by conventional means in the art, by adding an oil into water containing an emulsifier and stirring the mixture uniformly.

[0026] In the FDY preparation process, the polyester tow is oiled through an oil nozzle or oil wheel, and needs to be heated and stretched by a hot roller. If an emulsion is used, the water contained in it will evaporate and take away a large amount of heat. In order to fully heat the tow, the temperature of the hot roller needs to be increased. Using crude oil to directly oil the tow can reduce the heat taken away by the evaporation of water when the tow passes through the hot roller, saving energy. However, when the crude oil content is too high, the monofilaments of the FDY tow are easy to adhere to each other due to the viscosity of the oil, which is not conducive to forming a spiral winding structure with the POY tow in the pre-network, reducing the imitation cotton effect. Based on this, controlling the oil content of the FDY yarn at 60-70% can effectively balance the different requirements of low energy consumption and high imitation cotton effect.

[0027] In any of the above technical solutions, the stretching temperature of the FDY during stretching and setting is 85-88°C, the setting temperature is 95-110°C, and the stretching ratio after stretching and setting is 2.5-2.9.

[0028] The above-mentioned stretching and shaping is carried out in a hot roller box, which has 5 hot rollers. Among them, hot rollers HR1~HR3 are stretching rollers, and their temperatures correspond to the stretching temperature of 85~88℃, and hot rollers HR4~HR5 are shaping rollers, and their temperatures correspond to the shaping temperature of 95~110℃.

[0029] In any of the above technical solutions, the boiling water shrinkage of the POY yarn is 40-70%, and the elongation at break is 95-125%; the boiling water shrinkage of the FDY yarn is 5-7%, and the elongation at break is 28-30%; the linear density deviation rate of the ITY yarn is ±3.0%, the linear density variation coefficient is ≤1.3%, the breaking strength is ≥2.0 cN / dtex, and the boiling water shrinkage is 55.0±3.0%.

[0030] In a second aspect, the present application provides a polyester ITY yarn produced by any of the above-mentioned production methods.

[0031] In summary, this application has the following beneficial effects:

[0032] The present application adds a set of metering pump controllers to the FDY spinning equipment to achieve metered extrusion of POY yarn and FDY yarn, and then prepares ITY yarn with different shrinkage rate through pre-network and main network. In the pre-network process, the present application adjusts the tension of FDY yarn to be less than that of POY yarn, and controls the tension difference within 1 to 2 cN, forming an unexpected curling structure, in which FDY yarn is spirally wound on POY yarn, so that ITY yarn forms a pile loop in the axial direction, increases the gap between the yarn bundles, and exhibits a higher fluffiness and air permeability and moisture permeability and other super cotton-like effects.

[0033] Furthermore, the present application designs a three-slot spinneret with three ventilation slots and four yarn cakes, which can effectively alleviate the uneven cooling and turbulent vibration caused by the dense distribution of yarn bundles, reduce the breakage and hairy yarn phenomena, and improve the mechanical properties of ITY yarns. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the production process of ITY yarn in this application.

[0035] Figure 2 It is a schematic diagram of the structure of the spinneret in Example 1.

[0036] Figure 3 The left side diagram is the morphological structure diagram of the ITY silk obtained in Example 1 after being treated with boiling water; Figure 3 The figure on the right is the morphological structure diagram of the ITY silk obtained in Comparative Example 1 after being treated with boiling water.

[0037] Description of reference numerals:

[0038] 1. First ventilation slot; 2. Second ventilation slot; 3. Third ventilation slot; 4. Spinneret hole. DETAILED DESCRIPTION

[0039] The polyester melt intrinsic viscosity used in the following examples and comparative examples is 0.640 dL / g, the terminal carboxyl value is 44 mol / t, and the melting point is 254° C. The crude oil agents used for oiling FDY yarn and POY yarn are TK-1009 and TK-3588 obtained from Tongkun Group, respectively.

[0040] Embodiment 1, a method for producing polyester ITY yarn, the process steps are as follows:

[0041] See also Figure 1The polyester melt is metered by two sets of metering pump inverters, and is extruded from the spinneret of the DIO dual-channel spinning assembly through the metering pump. After being cooled and formed by annular blowing, the polyester monofilament is obtained, and the cooling air temperature is 20.5±1℃. The polyester monofilament obtained by extruding the melt controlled by one metering pump inverter enters the oil nozzle for oiling and bundling. The oiling uses a diluent oil with an oil content of 60%, and the oil temperature is controlled at 30-35℃. The oiled tow enters the hot roller box through the godet GR0 for drawing and shaping. Among them, the stretching ratio is 2.7, the temperature of the stretching rollers HR1-HR3 is 85-88℃, the temperature of the shaping roller HR4 is 95℃, the temperature of HR5 is 110℃, and the speed of the godet GR0 is 1000m / min, and the FDY yarn with an oil content of 0.62% is obtained. The melt is metered and controlled by another metering pump inverter. The polyester monofilament obtained after extrusion enters the oil nozzle for oiling and bundling. The oiling is done with diluent oil with an oil content of 20%. The oil temperature is controlled at 30-35°C to produce POY yarn with an oil content of 0.40%.

[0042] The FDY yarn obtained above is mixed with the POY yarn at the pre-network device through the wire guide disc GR1 for pre-networking to obtain mixed fibers. The rotation speed of the wire guide disc GR1 is 3130m / min, and the air pressure of the pre-network is 2.5bar. The mixed fiber then passes through the wire guide disc GR2 to enter the main network device. The rotation speed of the wire guide disc GR2 is 3150m / min, and the air pressure of the main network device is 4bar. The mixed fiber after the main network passes through the wire guide disc GR3 and enters the winding machine for winding. The rotation speed of GR3 is 3100m / min, and the winding speed is 3110m / min to obtain ITY yarn. Using a spinning tension meter, it is measured that the tension of the FDY yarn between the pre-network device and the wire guide disc GR1 is 12cN, and the tension of the POY yarn between the tunnel mouth and the pre-network device is 14cN.

[0043] See also Figure 2 The spinneret is a circular spinneret, and the spinneret holes 4 on the spinneret are arranged in concentric circles; the spinneret is provided with a first ventilation slot 1, a second ventilation slot 2 and a third ventilation slot 3 with a slot width of 7.5 mm in parallel. The first ventilation slot 1 passes through the center of the spinneret, and the spinneret holes 4 are symmetrically distributed on both sides with the first ventilation slot 1 as the center axis, and the second ventilation slot 2 and the third ventilation slot 3 respectively divide the spinneret holes 4 located on both sides of the first ventilation slot 1 into two parts of the same number.

[0044] Example 2, a method for producing polyester ITY yarn, is different from Example 1 in that the process parameters are selected differently, as shown in Table 1.

[0045] Example 3, a method for producing polyester ITY yarn, is different from Example 1 in that the process parameters are selected differently, as shown in Table 1.

[0046] Table 1. Process parameters of Examples 1 to 3

[0047]

[0048] Example 4, a method for producing polyester ITY yarn, is different from Example 1 in that the oil content of POY yarn is controlled at 0.22wt%, and the oil content of FDY yarn is controlled at 0.75wt%.

[0049] Example 5, a method for producing polyester ITY yarn, which is different from Example 1 in that the oil content of POY yarn is controlled at 0.48wt%, and the oil content of FDY yarn is controlled at 0.50wt%.

[0050] Example 6, a method for producing polyester ITY yarn, is different from Example 1 in that the FDY yarn is oiled with a diluent oil having an oil content of 50 wt%.

[0051] Example 7, a method for producing polyester ITY yarn, which is different from Example 1 in that TK-1009 crude oil is used for oiling the FDY yarn.

[0052] Example 8, a method for producing polyester ITY yarn, differs from Example 1 in that the spinneret adopts a spinneret of a commercially available DIO dual-channel assembly, which does not have the second ventilation slot and the third ventilation slot compared to the spinneret used in the present application. For the specific structure, see CN208933532U.

[0053] Comparative Example 1 is a method for producing polyester ITY yarn. The difference from Example 1 is that the rotation speed of the wire guide disc GR1 is 3100 m / min, and the rotation speed of the wire guide disc GR2 is 3150 m / min; the tension of the FDY yarn and the POY yarn is 14 cN.

[0054] Comparative Example 2 is a method for producing polyester ITY yarn. The difference from Example 1 is that the rotation speed of the wire guide disc GR1 is 3060 m / min, and the rotation speed of the wire guide disc GR2 is 3150 m / min; the tension of the FDY yarn is 16 cN, and the tension of the POY yarn is 14 cN.

[0055] Comparative Example 3, a method for producing polyester ITY yarn, is different from Example 1 in that the rotation speed of the wire guide disc GR1 is 3143 m / min, and the rotation speed of the wire guide disc GR2 is 3150 m / min; the tension of the FDY yarn is 10 cN, and the tension of the POY yarn is 14 cN.

[0056] Comparative Example 4, a method for producing polyester ITY yarn, differs from Example 1 in that the rotation speed of the wire guide disc GR1 is 3142 m / min, and the rotation speed of the wire guide disc GR2 is 3166 m / min; the tension of the FDY yarn is 14 cN, and the tension of the POY yarn is 16 cN.

[0057] Comparative Example 5, a method for producing polyester ITY yarn, is different from Example 1 in that the rotation speed of the wire guide disc GR1 is 3072 m / min, and the rotation speed of the wire guide disc GR2 is 3090 m / min; the tension of the FDY yarn is 8 cN, and the tension of the POY yarn is 10 cN.

[0058] The performance effects of the above embodiments and comparative examples are verified by experiments as follows.

[0059] 1. Refer to the provisions of FZ / T 54118-2019 "High Shrinkage Polyester Drawn Yarn / Polyester Pre-oriented Yarn Blended Yarn" to determine the linear density deviation rate, linear density variation coefficient, breaking strength, boiling water shrinkage and oil content of ITY yarn.

[0060] 2. During the production process, count the number of loose silk threads (times / day•108 pieces), hairy silk threads (times / day•108 pieces), and broken threads (times / day•108 pieces) within 10 days, and take the integer average of the results.

[0061] Table 2. ITY yarn performance test results

[0062]

[0063] 3. Take the ITY yarn with a specification of 120dtex / 108F prepared in the above examples and comparative examples, and weave it into a fabric using a single-cylinder circular hosiery machine. The fabric structure adopts a weft plain needle structure, and then test the air permeability and moisture permeability of the obtained fabric.

[0064] (1) Air permeability test method: According to GB / T 5453-1997 "Determination of air permeability of textile fabrics", the test conditions are temperature 20±3℃, relative humidity 65±5%; the test equipment is YG461E automatic air permeability tester; the sample area is 20cm 2 , test different parts of the same sample 10 times, and then take the average value to record the fabric air permeability.

[0065] (2) Water vapor permeability test method: Test in accordance with GB / T 12704.2-2009 "Test method for water vapor permeability of textile fabrics Part 1: Moisture absorption method". Test conditions are temperature 38±2℃, relative humidity 90±4%; test equipment: YG601D computerized fabric water vapor permeability tester, electronic balance with an accuracy of 0.001g, 4mm from the top of the wet cup, three samples, balance for 30min, and the combined weighing time shall not exceed 15s.

[0066] Table 3. Test results of fabric air and moisture permeability

[0067]

[0068] Result analysis:

[0069] like Figure 3 As shown, the ITY yarn obtained in Example 1 (left figure) has a higher curl after heat treatment than the ITY yarn obtained in Comparative Example 1 (right figure), and the pile loops are denser and more uniform in the length direction. As shown in Table 3, the moisture permeability and air permeability of the fabric obtained from the ITY yarn of Example 1 are also more outstanding. The reason may be that before the pre-networking of Comparative Example 1, the tension of the FDY yarn and the ITY yarn is consistent, and there is no tension difference. In Example 1, by controlling the tension difference between the FDY yarn and the POY yarn before the pre-networking within the expected range, it can promote the ITY blended fiber to form a curled structure of the FDY yarn spirally wrapped around the POY yarn in the pre-networking stage, so that the gap becomes larger, the fluffiness is improved, and it has a better cotton-like effect.

[0070] Referring to Table 2 and Table 3, it can be seen that compared with Example 1, Comparative Example 2 performs poorly in air permeability and moisture permeability; there are more floating silk, hairy silk and broken ends in the production process of Comparative Examples 3 to 5, and the air permeability and moisture permeability of Comparative Example 3 is poor. The reason may be that before pre-networking, the tension of FDY and POY in Comparative Example 3 is too large, resulting in local concentration of the internal silk thread distribution of ITY mixed fiber and uneven mixing. This unevenness reduces the cohesion between the mixed fiber threads, resulting in a decrease in the strength performance of ITY mixed fiber; and the formed velvet loop structure is also reduced. In Comparative Example 4, the tension difference is within the expected range, but the tension of POY is too large, and the oriented crystallinity of POY is low, which is prone to hairy silk and broken ends in high-speed spinning. In Comparative Example 5, the tension difference is within the expected range, but the tension of FDY is too small, which makes the tow shake too much during the spinning process, and adjacent tows are prone to merge or collide, which will cause unstable production phenomena such as floating silk, hairy silk and even broken silk under high-speed spinning.

[0071] As shown in Table 2, compared with Example 1, there are more floating filaments, hairy filaments and broken ends in the production process of Examples 4-5. The reason may be that in order to maintain the oil content of the mixed fiber, whether it is to reduce the POY filament content or further reduce the FDY oil content, it is not conducive to improving the bundle bundling effect and smoothness of the filament bundle, and it is easy to cause problems such as floating filaments and hairy filaments.

[0072] As shown in Table 2, compared with Example 1, Example 8 has more floating, fuzzy and broken threads in the production process. The reason may be that the conventional spinneret has a relatively dense distribution of filaments during the extrusion process, and the penetrating ability of the ring-blown cooling air to the filament bundle is reduced. The cooling of the filament bundle from the center to the outer layer is extremely uneven, resulting in turbulent vibration of the filaments, which are easy to shake when passing through the hot roller and the wire guide disk, resulting in floating, fuzzy and even broken threads. In addition, the uneven cooling also causes differences in the crystallization and orientation of the filament bundle, reducing the strength and stability of the filament bundle.

[0073] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for producing polyester ITY yarn, characterized in that: The polyester melt is extruded from the spinning assembly under the control of two groups of metering pump frequency converters, and is cooled and formed to obtain polyester monofilaments. The polyester monofilaments extruded by one metering pump frequency converter are oiled by the oil nozzle, stretched and shaped by the GR0 godet, and drawn by the hot roller box to obtain FDY yarns. The polyester monofilaments extruded by another metering pump frequency converter are oiled to obtain POY yarns. The FDY yarns are mixed with the POY yarns in the pre-netting device through the GR1 godet, and then enter the main netting device through the GR2 godet for main netting, and finally enter the winder through the GR3 godet for winding to obtain ITY yarns. Before entering the pre-network device, the tension of the FDY yarn is 10-14 cN, the tension of the POY yarn is 12-16 cN, and the tension of the FDY yarn is less than that of the POY yarn, and the tension difference is 1-2 cN; The oil content of the polyester ITY yarn is 0.50±0.1%, the oil content of the POY yarn is 0.40±0.05%, and the oil content of the FDY yarn is 0.62±0.1%.

2. The production method according to claim 1, characterized in that The spinning temperature is 286-290°C, the cooling air temperature is 20.5±1°C, the air pressure of the pre-network device is 1-3 bar, and the air pressure of the main network device is 4-6 bar; the rotation speed of the wire guide plate GR0 is 800-1100 m / min, the rotation speed of the wire guide plate GR1 is 2930-3300 m / min, the rotation speed of the wire guide plate GR2 is 2940-3320 m / min, the rotation speed of the wire guide plate GR3 is 2930-3300 m / min, and the winding speed is 2970-3300 m / min; the speed difference between the wire guide plate GR1 and the wire guide plate GR2 is 10-20 m / min.

3. The production method according to claim 1, characterized in that The spinning assembly is a DIO dual-channel assembly, which has a spinneret, and the spinnerets on the spinneret are arranged in concentric circles; the first ventilation slot, the second ventilation slot and the third ventilation slot are arranged in parallel on the spinneret, and the spinnerets are symmetrically distributed with the first ventilation slot as the central axis, and the second ventilation slot and the third ventilation slot respectively divide the spinnerets located on both sides of the first ventilation slot into two parts of equal number.

4. The production method according to claim 3, characterized in that: The widths of the first ventilation slot, the second ventilation slot and the third ventilation slot are all 7-8 mm.

5. The production method according to claim 1, characterized in that: The FDY yarn is oiled with a diluent oil with an oil content of 60 to 70 wt%, and the POY yarn is oiled with a diluent oil with an oil content of 10 to 20 wt%.

6. The production method according to claim 1, characterized in that: The drawing temperature of the FDY during drawing and setting is 85-88° C., the setting temperature is 95-110° C., and the stretching ratio after drawing and setting is 2.5-2.

9.

7. The production method according to claim 1, characterized in that: The boiling water shrinkage of the POY yarn is 40-70%, and the breaking elongation is 95-125%; the boiling water shrinkage of the FDY yarn is 5-7%, and the breaking elongation is 28-30%; the linear density deviation rate of the ITY yarn is ±3.0%, the linear density variation coefficient is ≤1.3%, the breaking strength is ≥2.00 cN / dtex, and the boiling water shrinkage is 55.0±3.0%.

8. A polyester ITY yarn, characterized in that: The product is prepared by the production method described in any one of claims 1 to 7.

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