Pre-oriented yarn with large monofilament fineness and production equipment and method thereof

Abstract

The present invention relates to a pre-oriented yarn with large single-filament fineness and its production equipment and method. The production equipment includes a melt conveying system, a spinning box, a sand cup, a spinneret, a ring-blowing device, an oiling device, and a winding device arranged in sequence. The height of the wind tube of the ring-blowing device is 39-41 cm, and the air output of the upper half of the wind tube is 65-70% of the air output of the lower half; a vertical frustum structure is fixedly set in the sand cup, and three drainage devices are set on the circumference of the upper part of the frustum; the preparation process parameters are: the length of the windless zone is 45-60 mm, the cooling air temperature is 20-22 ° C; the product breaking strength is ≥2.30 cN / dtex, the coefficient of variation of the elongation at break CV / % ≤3.00, and the yarn unevenness CV / % ≤1.00. The production equipment of the present invention innovatively transforms the cooling device, the component sand cup, and the oiling device, and has a simple structure; the preparation method is simple; and the uniformity of the pre-oriented yarn product with large single-filament fineness is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pre-oriented yarn production, and relates to a pre-oriented yarn with large monofilament fineness and a production device and method thereof. Background Art

[0002] In the production process of melt-spun POY pre-oriented yarn, the choice of cooling method has a significant impact on product characteristics. There are two cooling methods: one is side-blowing cooling, which is mainly suitable for products with larger monofilament fineness. This is because products with larger monofilament fineness require lower cooling speeds and longer cooling distances, while side-blowing has less loss when passing through the monofilaments close to the air outlet, and can still have a good cooling effect on the monofilaments far away from the end; the other is ring-blowing cooling, which is mainly suitable for products with smaller monofilament fineness. Ring-blowing ensures that the cooling air blown out to all sides has a uniform wind speed at all points in the circumferential direction, and the cooling air volume required for fine-denier products is small. Ring-blowing cooling benefits from the design of cooling air blowing inward from all directions, which greatly reduces the problem of cooling air loss.

[0003] Generally speaking, coarse denier products with specifications of 378-545dtex / 96f are suitable for production on side-blown cooling systems. However, due to the high uniformity requirements of customers for this product, the disadvantage of side-blown cooling, such as single-sided cooling, restricts the improvement of product uniformity. This results in large CVs in physical indicators such as elongation, strength, thermal stress, and evenness, which cannot meet customer requirements.

[0004] To solve the above problems, Reference 1 (Research and Development of 680dtex / 192f Bright Trilobal Polyester Filament [J]. Polyester Industry, 2011, 24(2): 20-23.) describes the cooling conditions of 680dtex / 192f bright trilobal polyester filament (single yarn density 3.54dpf) using side blowing. By adding horizontal rectification technology to improve the laminar flow effect of the cooling air, the uniformity of physical indicators is reduced. However, Reference 2 (Equipment Transformation and Process Adjustment of Coarse Denier Polyester POY Side Blowing Spinning Production Line [J]. Synthetic Fibers, 2011, (4): 38-40.) mentions that although some auxiliary equipment such as laminar flow plates and air ducts were added to the side blowing yarn chamber, the problem of mutual interference between cooling air of different spindles was not solved because the side blowing yarns share the same yarn chamber, resulting in differences in physical indicators. At the same time, after changing from side blowing to ring blowing, Document 2 mainly produces 134dtex / 144f porous fine denier polyester pre-oriented yarn, and cannot produce 378-545dtex / 96f coarse denier products.

[0005] Therefore, it is of great significance to study a pre-oriented yarn with large monofilament fineness and a production device and method thereof to solve the problems existing in the prior art. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems existing in the prior art and provide a pre-oriented yarn with large monofilament fineness and a production device and method thereof.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A production equipment for pre-oriented yarns with large single-filament fineness, comprising a melt conveying system, a spinning box, a sand cup, a spinneret, a cooling device, an oiling device and a winding device arranged in sequence, wherein the cooling device is a ring-blowing device, the height of the wind tube of the ring-blowing device is 39 to 41 cm, and the air output of the upper half of the wind tube is 65 to 70% of the air output of the lower half; since the ring-blowing wind tube is close to the filament bundle and the cooling wind speed is low, the fiber cooling can be achieved quickly, so the length of the ring-blowing wind tube is generally short. In the present invention, the wind tube is extended from the general length of 19 to 27 cm to 39 to 41 cm, mainly to extend the cooling distance and make its effect closer to side blowing. After the distance is extended, since the cooling rate of the ring-blowing is faster, the cooling is basically completed in the front half of the wind tube, so simply extending the length of the wind tube has no practical significance. Therefore, the wind pressure of the front half of the wind tube is reduced by 30 to 35%, that is, the air output is reduced by 30 to 35%, so that the cooling is prevented from being completed too early, thereby achieving the purpose of extending the cooling distance;

[0009] The spinneret diameter is 104-105 mm;

[0010] The sand cup includes a sand cup body, a vertical frustum structure is fixedly arranged in the sand cup body, and three drainage devices are arranged on the circumference of the upper part of the frustum. The drainage devices are inclined arc plates, and the inner arc surface of the arc plate is in contact with the circumference of the frustum. The projection of the inner arc surface of the three arc plates on the horizontal plane forms a complete circle.

[0011] Taking into account the mutual influence between the sand cup and the spinneret in the component accessories during the production process, the sand cup structure is changed to make it more consistent with the characteristics of the spinneret. However, since the fiber variety of the present invention is a coarse denier product with a large single-filament fineness, the melt flow rate is large, which will cause uneven pressure in each area when the melt flows in the sand cup. Placing a frustum in the center position can match the distribution characteristics of the spinneret's spinneret holes, but it does not effectively solve the problem of uneven pressure in each area. Therefore, through innovative design, three drainage devices are set on the upper part of the frustum, and the inner edge of the drainage device fits the frustum and is inclined at a certain angle to the horizontal plane. When the melt enters the sand cup at a vertical angle, it will be changed in direction by the drainage device, so that the melts in different vertical areas will mix with each other, making the melt pressure in the sand cup more uniform.

[0012] As the preferred technical solution:

[0013] In the above-mentioned pre-oriented yarn production equipment with large single-filament fineness, the inner diameter of the wind tube of the ring-blowing device is 104-105 mm, and the wind pressure in the upper half of the wind tube is 50-60 Pa.

[0014] The above-mentioned equipment for producing pre-oriented yarns with large single-filament fineness has a sand cup body that is a cylindrical structure with an outer diameter of 104-105 mm, an inner diameter of 92-93 mm, and a height of 69-70 mm. The bottom of the cylinder is provided with a plurality of through holes, all of which are arranged in a circle of 5-6 circles. The diameter of the through holes is 2.0-2.5 mm, and the distance between two adjacent through holes is 9-11 mm.

[0015] Two layers of filter screens are arranged between the frustum and the bottom of the sand cup body.

[0016] As described above, in the production equipment for pre-oriented yarns with large single yarn fineness, the upper end diameter of the truncated cone is 8 to 10 mm, the lower end diameter is 38 to 40 mm, and the height is 40 to 42 mm.

[0017] As described above, in the pre-oriented yarn production equipment with large single-filament fineness, the highest point of the inner arc surface of the arc plate is 8 to 10 mm away from the upper end of the truncated cone, and the lowest point is 20 to 22 mm away from the lower end of the truncated cone; the arc length of the inner arc surface of the arc plate is 17 to 19 mm, and the angle between the plane of the arc plate and the horizontal plane is 28° to 30°.

[0018] As described above, a pre-oriented yarn production device with large single-filament fineness has a truncated cone that is a hollow truncated cone that is closed at the top and bottom. The truncated cone is made of ceramic material and has a smooth surface. The present invention designs the truncated cone structure that blocks the melt to be made of ceramic material, which is small at the top and large at the bottom and has a cavity inside. The main purposes are: first, the surface of the ceramic material is smooth, the friction between the melt and it is small, and the flow rate is less affected by it; second, when the melt passes through the ceramic cylinder that is small at the top and large at the bottom, as the cross-sectional area gradually decreases, the flow rate can be gradually increased to appropriately alleviate the uneven pressure distribution in the sand cup and improve production stability; third, the characteristics of the cavity in the ceramic cylinder can reduce heat conduction and reduce heat loss from the melt. All of the above can prevent the quality of the melt from declining and improve product uniformity.

[0019] As described above, a pre-oriented yarn production equipment with large single-filament fineness is provided, wherein the oiling device includes an oil guide pipe, an atomizing nozzle, an oil receiving device and a roller. The atomizing nozzle is connected to the oil guide pipe through a bracket I. The oil receiving device is an inverted trapezoidal structure. The oil receiving device is placed obliquely above the roller, and the angle with the horizontal plane is 40° to 50°. The bottom of the oil receiving device is 4 to 6 mm away from the upper part of the roller. The roller is fixed by bracket II, and the surface of the roller is in contact with the filament bundle. A certain oiling rate is given by the oil pump, and the filament bundle is oiled by connecting the atomizing nozzle through the oil guide pipe. The excess oil is collected by the oil receiving device and then led to the roller by gravity to oil the filament bundle again.

[0020] As described above, in the production equipment for pre-oriented yarns with large single yarn fineness, the roller is a horizontally placed cylinder, and the surface of the roller is made of ceramic material.

[0021] The present invention also provides a method for preparing pre-oriented yarn with large single yarn fineness using the production equipment as described in any of the above items, the main process parameters being: melt temperature of 279-285°C, spinning box temperature of 285-289°C, windless zone length of 45-60 mm, cooling air temperature of 20-22°C, cooling air relative humidity of 70-80%, oil concentration of 9.8-10.3wt%, and winding speed of 2800-3215 m / min.

[0022] The present invention also provides a pre-oriented yarn with large single yarn fineness prepared by the method as described above. The specifications of the pre-oriented yarn with large single yarn fineness are 378~545dtex / 96f, the breaking strength is ≥2.30cN / dtex, the elongation at break is 128.0±3.0%, the coefficient of variation of the elongation at break CV / %≤3.00, the yarn unevenness CV / %≤1.00, the deviation of the thermal stress from the center value is within 3%, and the center value is 80~185cN.

[0023] Principle of the invention:

[0024] In order to solve the problem in the prior art that products with large monofilament fineness are cooled by side-blowing during production, resulting in poor product uniformity, the present invention first innovatively combines the respective advantages of annular side-blowing, adopts annular blowing for cooling, and simultaneously adopts a low wind speed and long-distance cooling method. Secondly, since the larger the diameter of the spinneret, the greater the distance between the monofilaments, the better the cooling effect of the cooling air will be, so choosing a large spinneret will help improve cooling, but this also leads to an increase in the size of the component, which in turn slows down the flow rate of the melt when passing through the large component, which is not conducive to improving product quality. Therefore, the present invention has carried out technical innovation on the component sand cup to solve this problem. Finally, the oiling design is innovated to improve the uniformity of oiling. Through these innovations, indicators such as product uniformity are improved to meet customer requirements.

[0025] Regarding the cooling device, the present invention designs the cooling duct to be 39 to 41 mm long. By referring to the cooling characteristics of side-blown air, the cooling distance is rationally extended, making the cooling distance suitable for the large single-filament fineness of the product. At the same time, the density of the duct mesh tube in the upper half of the duct is increased to reduce air permeability, achieving an air output of 0.65 to 0.7 times that of the duct in the lower half. As a result, when the filament bundle passes through the duct for cooling, the longer duct increases the cooling distance of the filament bundle. At the same time, because the cooling air at the upper end of the duct is smaller, the cooling speed is slowed down, improving the shortcomings of the original duct's short cooling distance and excessively fast cooling speed, enhancing cooling uniformity and improving product uniformity.

[0026] In terms of component sand cup modification. The present invention fixes a truncated cone structure in the sand cup body. In this way, due to the obstruction of the central truncated cone, if the sand cup is regarded as a pipe, the cross-sectional area of ​​the pipe originally available for the melt to pass through is reduced, the melt flow rate will increase, and the residence time in the sand cup will be shortened, thereby preventing the degradation of the melt quality. At the same time, three drainage devices are provided on the upper part of the truncated cone, and the inner edge of the drainage device fits the truncated cone and forms a certain inclination angle with the horizontal plane. When the melt enters the sand cup at a vertical angle, it will be changed in direction by the drainage device. In this way, the melts in different vertical regions will mix with each other, making the melt pressure in the sand cup more uniform.

[0027] Regarding the oiling device, the oil enters the atomizing nozzle through the oil guide pipe, is atomized by the nozzle and sprayed toward the tow, performing the first oiling of the tow. At this time, some of the oil that is not absorbed by the tow or the oil that is not atomized properly will fall to the lower position on the other side of the tow. At this time, the designed inverted trapezoidal oil receiving device will collect this oil and guide it to the roller with a ceramic surface. The roller has a certain speed and the tow is close to the roller surface. At this time, the oil on the roller surface will be further absorbed by the tow, thus completing the second oiling. After two oiling, the uniformity of the oiling of the tow is improved, further improving the uniformity of the product.

[0028] Beneficial effects:

[0029] (1) The present invention provides a pre-oriented yarn production equipment with large single-filament fineness, which extends the length of the air duct from the general 19 to 27 cm to 39 to 41 cm. At the same time, by modifying the component sand cup, three drainage devices are set on the upper part of the circular table, so that the melt pressure in the sand cup is more uniform, and combined with the design of the oil receiving device with an inverted trapezoidal structure, the structure is simple and the oiling uniformity is improved.

[0030] (2) The method of the present invention for preparing pre-oriented yarns with large single-filament fineness improves the shortcomings of the original air duct, such as short cooling distance and excessively fast cooling speed; at the same time, the melt pressure in the sand cup is more uniform and the oiling of the yarn bundle is more uniform, thereby improving the uniformity of the product.

[0031] (3) The present invention produces a pre-oriented yarn with large single-filament fineness, and the uniformity index of the product is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the structural diagram of the spinneret;

[0033] Figure 2 Schematic diagram of the sand cup and spinneret structure, where the dotted arrow represents the direction of melt entry;

[0034] Figure 3 Schematic diagram of the sand cup and frustum structure;

[0035] Figures 4-5 Schematic diagram of the structure of the frustum and the drainage device at different angles; the dotted arrow represents the direction of melt entry;

[0036] Figure 6 This is the front view of the cooling device. The area between the two dotted lines in the figure represents the range of the tow cooling;

[0037] Figure 7 This is the rear view of the oiling device;

[0038] Figure 8 This is the left side view of the oiling device;

[0039] Among them, 1-spinneret distribution area, 2-central area without spinneret holes, 3-spinneret, 4-sand cup, 5-drainage device, 6-round table, 7-air cylinder, 8-upper part of air cylinder, 9-oil guide pipe, 10-atomizing nozzle, 11-oil receiving device, 12-roller, 13-filament bundle. DETAILED DESCRIPTION

[0040] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0041] The test methods involved in the performance indicators in the embodiments and comparative examples of the present invention are as follows:

[0042] Breaking strength, breaking elongation, breaking elongation variation coefficient: According to the "Test method for tensile properties of chemical fiber filaments" (GB / T 14344-2022) standard, the YG023B-Ⅱ fully automatic single yarn strength tester was used to test the breaking elongation of the yarn bundle. The specific process is as follows: first, the yarn bundle was placed in an environment with a temperature of 20±2℃ and a humidity of 65±5% for 4 hours; then, the fully automatic single yarn strength tester was used for tensile testing. Before the test, the clamping length of the yarn bundle was accurately set to 500±1.0mm by the upper and lower clamps, and a pre-tension (0.05±0.005cN / dtex) was applied by the manipulator to stabilize the yarn bundle; during the test, the lower clamp stretched the yarn bundle at a set speed (500mm / min) at a uniform speed until the yarn bundle broke; during the stretching process, the force sensor recorded the data in real time, and the relationship curve between strength and elongation was drawn through the data collection system; finally, the breaking strength, elongation at break and coefficient of variation of elongation at break of the yarn bundle were obtained through data processing and analysis.

[0043] Yarn unevenness: The test is conducted using a USTER 5 yarn uniformity meter in accordance with the "Test Method for Yarn Unevenness of Chemical Fiber Filament - Capacitance Method" (GB / T 14346-2015). The yarn tow is first placed in an environment with a temperature of 20±2°C and a humidity of 65±5% for 2 hours. The yarn tow is then passed through the two electrodes of a capacitor at a uniform speed. The mass of each equal interval is converted into an electrical signal. The percentage of the standard deviation of all test electrical signals to the average value is the yarn unevenness. The test speed is 200 m / min, and the yarn tow test time is 2.5 minutes.

[0044] Thermal stress: According to the standard "Test Method for Dynamic Thermal Stress of Polyester Pre-oriented Yarn" (FZ / T 50051-2020), the test is carried out using a YG 367 thermal stress tester. The specific process is as follows: first, the yarn tow is placed in an environment with a temperature of 20±2°C and a humidity of 65±5% for 4 hours, and then the yarn tow is passed through a heating device and a drawing device at a specific speed and pre-tension (the specific speed and pre-tension parameters are set in accordance with Sections 8.1 and 8.3 of the standard) to test the tensile stress (i.e. thermal stress) generated by the yarn tow being drawn under heating conditions.

[0045] Example 1

[0046] A production device for pre-oriented yarn with large single-filament fineness, comprising a melt conveying system, a spinning box, a sand cup 4, a spinneret 3, a cooling device, an oiling device and a winding device arranged in sequence;

[0047] like Figure 6 As shown, the cooling device is a ring-blowing device, the height of the wind tube 7 of the ring-blowing device is 39 cm, the inner diameter of the wind tube is 104 mm, the wind pressure of the upper part 8 of the wind tube is 50 Pa; the air output of the upper part 8 of the wind tube is 65% of the air output of the lower part;

[0048] like Figures 1-2 As shown, the spinneret 3 has a diameter of 104 mm; the spinneret 3 includes a spinneret hole distribution area 1 and a central spinneret hole-free area 2, and the central spinneret hole-free area 2 has a diameter of 35 mm;

[0049] The sand cup 4 includes a sand cup body, which is a cylindrical structure with an outer diameter of 104 mm, an inner diameter of 92 mm, and a height of 69 mm. A plurality of through holes are opened at the bottom of the cylinder. All through holes are arranged in 5 circles. The diameter of the through holes is 2 mm, and the distance between two adjacent through holes is 9 mm.

[0050] like Figure 3 As shown, a vertical truncated cone structure is fixedly set in the sand cup body. The truncated cone 6 is a hollow truncated cone with upper and lower closed parts. The truncated cone 6 is made of ceramic and has a smooth surface. The upper end diameter of the truncated cone 6 is 8mm, the lower end diameter is 38mm, and the height is 40mm. Two layers of filter screens are provided between the truncated cone and the bottom of the sand cup body.

[0051] like Figures 4-5 As shown, three drainage devices 5 are provided on the circumference of the upper part of the truncated cone 6. The drainage devices 5 are inclined arc-shaped plates, and the inner arc surface of the arc-shaped plates is in contact with the circumference of the truncated cone 6. The projections of the inner arc surfaces of the three arc-shaped plates on the horizontal plane form a complete circle. The highest point of the inner arc surface of the arc plate is 8 mm from the upper end of the truncated cone 6, and the lowest point is 22 mm from the lower end of the truncated cone 6. The arc length of the inner arc surface of the arc plate is 17 mm, and the angle between the plane of the arc plate and the horizontal plane is 28°.

[0052] like Figures 7-8 As shown, the oiling device includes an oil guide pipe 9, an atomizing nozzle 10, an oil receiving device 11 and a roller 12. The roller 12 is a horizontally placed cylinder, and the roller surface is made of ceramic material; the atomizing nozzle 10 is connected to the oil guide pipe 9 through the bracket I, and the oil receiving device 11 is an inverted trapezoidal structure. The oil receiving device 11 is placed obliquely above the roller 12, and the angle with the horizontal plane is 40°. The roller 12 is fixed by the bracket II, and the surface of the roller 12 is in contact with the tow 13.

[0053] Example 2

[0054] A production device for pre-oriented yarn with large single-filament fineness, comprising a melt conveying system, a spinning box, a sand cup, a spinneret, a cooling device, an oiling device and a winding device arranged in sequence;

[0055] The cooling device is a circular blowing device with a wind tube height of 40 cm, an inner diameter of 104 mm, and a wind pressure of 55 Pa in the upper part of the wind tube. The air volume in the upper part of the wind tube is 68% of the air volume in the lower part.

[0056] The spinneret has a diameter of 104 mm. The spinneret includes a spinneret hole distribution area and a central spinneret hole-free area. The central spinneret hole-free area has a diameter of 38 mm.

[0057] The sand cup includes a sand cup body, which is a cylindrical structure with an outer diameter of 104mm, an inner diameter of 92.5mm, and a height of 69.5mm. There are multiple through holes at the bottom of the cylinder, all of which are arranged in 5 circles. The diameter of the through holes is 2.25mm, and the distance between two adjacent through holes is 10mm.

[0058] A vertical cone structure is fixed inside the sand cup body. The cone is a hollow cone with upper and lower closed parts. The cone is made of ceramic with a smooth surface. The upper diameter of the cone is 9mm, the lower diameter is 39mm, and the height is 41mm. Two layers of filter screen are installed between the cone and the bottom of the sand cup body.

[0059] Three drainage devices are installed on the circumference of the upper part of the truncated platform. The drainage devices are inclined arc plates, and the inner arc surface of the arc plates is in contact with the circumference of the truncated platform. The projection of the inner arc surface of the three arc plates on the horizontal plane forms a complete circle. The highest point of the inner arc surface of the arc plate is 9mm from the upper end of the truncated platform, and the lowest point is 21mm from the lower end of the truncated platform. The arc length of the inner arc surface of the arc plate is 18mm, and the angle between the plane of the arc plate and the horizontal plane is 29°.

[0060] The oiling device includes an oil guide pipe, an atomizing nozzle, an oil receiving device and a roller. The atomizing nozzle is connected to the oil guide pipe through bracket I. The oil receiving device is an inverted trapezoidal structure. The oil receiving device is placed obliquely on the upper part of the roller and has an angle of 46° with the horizontal plane. The roller is fixed by bracket II, and the surface of the roller is in contact with the tow.

[0061] Example 3

[0062] A production device for pre-oriented yarn with large single-filament fineness, comprising a melt conveying system, a spinning box, a sand cup, a spinneret, a cooling device, an oiling device and a winding device arranged in sequence;

[0063] The cooling device is a circular blowing device with a wind tube height of 41 cm, an inner diameter of 105 mm, and a wind pressure of 60 Pa in the upper part of the wind tube. The air volume in the upper part of the wind tube is 70% of the air volume in the lower part.

[0064] The spinneret has a diameter of 105 mm. The spinneret includes a spinneret hole distribution area and a central spinneret hole-free area. The central spinneret hole-free area has a diameter of 40 mm.

[0065] The sand cup includes a sand cup body, which is a cylindrical structure with an outer diameter of 105mm, an inner diameter of 93mm, and a height of 70mm. There are multiple through holes at the bottom of the cylinder, all of which are arranged in 6 circles. The diameter of the through holes is 2.5mm, and the distance between two adjacent through holes is 11mm.

[0066] A vertical cone structure is fixed inside the sand cup body. The cone is a hollow cone with upper and lower closed parts. The cone is made of ceramic with a smooth surface. The upper diameter of the cone is 10mm, the lower diameter is 40mm, and the height is 42mm. Two layers of filter screen are installed between the cone and the bottom of the sand cup body.

[0067] Three drainage devices are installed on the circumference of the upper part of the truncated platform. The drainage devices are inclined arc plates, and the inner arc surface of the arc plates is in contact with the circumference of the truncated platform. The projection of the inner arc surface of the three arc plates on the horizontal plane forms a complete circle. The highest point of the inner arc surface of the arc plate is 10mm from the upper end of the truncated platform, and the lowest point is 20mm from the lower end of the truncated platform. The arc length of the inner arc surface of the arc plate is 19mm, and the angle between the plane of the arc plate and the horizontal plane is 30°.

[0068] The oiling device includes an oil guide pipe, an atomizing nozzle, an oil receiving device and a roller. The atomizing nozzle is connected to the oil guide pipe through bracket I. The oil receiving device is an inverted trapezoidal structure. The oil receiving device is placed obliquely above the roller and has an angle of 50° with the horizontal plane. The roller is fixed by bracket II, and the surface of the roller is in contact with the tow.

[0069] Example 4

[0070] A method for preparing pre-oriented yarn with large monofilament fineness, the specific process is as follows

[0071] The production equipment of Example 1 is used to prepare pre-oriented yarns with large monofilament fineness;

[0072] The process parameters are: melt temperature 279°C, spinning box temperature 285°C, windless zone length 45 mm, cooling air temperature 20°C, cooling air relative humidity 80%, oil concentration 9.8wt%, and winding speed 2800 m / min.

[0073] The final pre-oriented yarn with large single fiber fineness has a specification of 378dtex / 96f (three-leaf), a breaking strength of 2.42cN / dtex, an elongation at break of 127.5%, a coefficient of variation of elongation at break CV / % of 1.78, a yarn unevenness CV / % of 0.89, a deviation of thermal stress from the center value of 2.14%, and a center value of 80cN.

[0074] Example 5

[0075] A method for preparing pre-oriented yarn with large monofilament fineness, the specific process is as follows

[0076] The production equipment of Example 2 is used to prepare pre-oriented yarns with large monofilament fineness;

[0077] The process parameters are: melt temperature 282°C, spinning box temperature 287°C, windless zone length 52 mm, cooling air temperature 21°C, cooling air relative humidity 75%, oil concentration 10wt%, and winding speed 3000 m / min.

[0078] The final pre-oriented yarn with large single-filament fineness has a specification of 430dtex / 96f (round hole), a breaking strength of 2.64cN / dtex, an elongation at break of 128.9%, a coefficient of variation of elongation at break CV / % of 1.41, a yarn unevenness CV / % of 0.84, a deviation of thermal stress from the center value of 2.34%, and a center value of 125cN.

[0079] Example 6

[0080] A method for preparing pre-oriented yarn with large monofilament fineness, the specific process is as follows

[0081] The production equipment of Example 3 is used to prepare pre-oriented yarns with large monofilament fineness;

[0082] The process parameters are: melt temperature 285°C, spinning box temperature 289°C, windless zone length 60 mm, cooling air temperature 22°C, cooling air relative humidity 70%, oil concentration 10.3wt%, and winding speed 3215 m / min.

[0083] The final pre-oriented yarn with large single-filament fineness has a specification of 545dtex / 96f (round hole), a breaking strength of 2.49cN / dtex, an elongation at break of 128.4%, a coefficient of variation of elongation at break CV / % of 2.02, a yarn unevenness CV / % of 0.91, a deviation of thermal stress from the center value of 1.97%, and a center value of 185cN.

Claims

1. A production apparatus for pre-oriented yarns with large single-filament fineness, comprising a melt delivery system, a spinning manifold, a sand cup, a spinneret, a cooling device, an oiling device, and a winding device, arranged in sequence, characterized in that: The cooling device is a ring-blowing device, the height of the wind tube of the ring-blowing device is 39 to 41 cm, and the air output of the upper half of the wind tube is 65 to 70% of the air output of the lower half; The spinneret diameter is 104-105 mm; The sand cup includes a sand cup body, a vertical frustum structure is fixedly arranged in the sand cup body, and three drainage devices are arranged on the circumference of the upper part of the frustum. The drainage devices are inclined arc plates, and the inner arc surface of the arc plate is in contact with the circumference of the frustum. The projection of the inner arc surface of the three arc plates on the horizontal plane forms a complete circle. The sand cup body is a cylindrical structure with an outer diameter of 104-105mm, an inner diameter of 92-93mm, and a height of 69-70mm. There are multiple through holes at the bottom of the cylinder. All through holes are arranged in 5-6 circles. The diameter of the through holes is 2.0-2.5mm, and the distance between two adjacent through holes is 9-11mm. There are two layers of filter screens between the round table and the bottom of the sand cup body; The diameter of the upper end of the cone is 8-10 mm, the diameter of the lower end is 38-40 mm, and the height is 40-42 mm; The highest point of the inner arc surface of the arc plate is 8 to 10 mm from the upper end of the truncated cone, and the lowest point is 20 to 22 mm from the lower end of the truncated cone. The arc length of the inner arc surface of the arc plate is 17 to 19 mm, and the angle between the plane of the arc plate and the horizontal plane is 28° to 30°. The specifications of pre-oriented yarns with large single yarn fineness are 378~545dtex / 96f.

2. The production equipment for pre-oriented yarn with large single yarn fineness according to claim 1, characterized in that: The inner diameter of the air duct of the circular blowing device is 104-105 mm, and the wind pressure in the upper half of the air duct is 50-60 Pa.

3. The production equipment for pre-oriented yarn with large single yarn fineness according to claim 1, characterized in that: The frustum is a hollow frustum that is closed at the top and bottom. The frustum is made of ceramic and has a smooth surface.

4. The production equipment for pre-oriented yarn with large single yarn fineness according to claim 1, characterized in that: The oiling device includes an oil guide pipe, an atomizing nozzle, an oil receiving device and a roller. The atomizing nozzle is connected to the oil guide pipe through bracket I. The oil receiving device is an inverted trapezoidal structure. The oil receiving device is placed obliquely above the roller, and the angle with the horizontal plane is 40°~50°. The roller is fixed by bracket II, and the roller surface is in contact with the wire bundle.

5. The production equipment for pre-oriented yarn with large single yarn fineness according to claim 4, characterized in that: The roller is a horizontally placed cylinder with a surface made of ceramic.

6. A method for preparing pre-oriented yarns with large single-filament fineness using the production equipment according to any one of claims 1 to 5, characterized in that The main process parameters are: melt temperature 279-285°C, spinning box temperature 285-289°C, windless zone length 45-60 mm, cooling air temperature 20-22°C, cooling air relative humidity 70-80%, oil concentration 9.8-10.3wt%, and winding speed 2800-3215 m / min.

7. A pre-oriented yarn with large single-filament fineness obtained by the method according to claim 6, characterized in that: The breaking strength of the pre-oriented yarn with large single yarn fineness is ≥2.30cN / dtex, the elongation at break is 128.0±3.0%, the coefficient of variation of the elongation at break CV / %≤3.00, the yarn unevenness CV / %≤1.00, the deviation of the thermal stress from the center value is within 3%, and the center value is 80~185cN.

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