Polyester drawn slub yarn and preparation method thereof

Abstract

The present invention belongs to the technical field of polyester filaments and relates to a polyester drawn slub yarn and a preparation method thereof. The preparation method comprises the following steps: after extruding a polyester melt through a spinneret, cooling it using alternating wind pressures, and then oiling and winding it to produce the polyester drawn slub yarn. The produced polyester drawn slub yarn has a segment length of 2 to 2.5 meters, a breaking strength greater than 3.8 cN / dtex, an elongation at break of 35.0±3.0%, and a boiling water shrinkage of 15.0±1.0%. By using alternating wind pressures, the present invention can achieve alternating periods of high and low elongation at break and boiling water shrinkage on continuous fibers. After thermal dyeing of the fiber fabric, the fabric will exhibit a dense, darkly stained section and a lightly stained section with less shrinkage, achieving a fancy differential shrinkage effect.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester filaments and relates to polyester drawn slub yarn and a preparation method thereof. Background Art

[0002] In recent years, with the continued growth of the domestic economy and the people's pursuit of a better quality of life, consumers have increasingly demanded higher standards for polyester fabrics, particularly in terms of texture and functionality. This has also prompted the development of differentiated polyester products, with a continuous emergence of various innovative products. Among them, fabrics woven from drawn polyester slub yarn, which exhibit distinctive colored stripes after dyeing, have been highly favored by the market and customers, leading to their widespread use.

[0003] However, existing technologies for producing slubby yarns have problems such as poor slubby effect and unstable production. For example, in the literature (Discussion on the Production Process of 82.5dtex / 144fFDY Slubby Yarn [J]. Polyester Industry. 2018, 31(2): 37-39), slubby yarn can be produced by replacing the hot roller for stretching with a hot roller with equidistant slots at the head end. However, since the slubby roller for stretching the yarn is equidistantly slotted, it is easy for the yarn tow to suddenly become thick or thin, affecting the subsequent weaving efficiency and the slubby effect on the fabric.

[0004] To solve the above problems, patent CN102206880A discloses a multi-color polyester slub fully drawn yarn produced by variable speed hot roller and its production method. The yarn is in the shape of a bamboo knot with alternating thick and thin segments along the axial direction produced by variable speed of a second hot roller. Although it solves the problem of sudden coarseness or thinness of the yarn bundle locally and improves the slub effect of the cloth, the yarn bundle is likely to slip or shake on the hot roller or even break when the second hot roller suddenly decelerates, and its output cannot be increased.

[0005] Therefore, a polyester drawn slub yarn and a preparation method thereof are needed to solve the above problems, which is of great significance. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems existing in the prior art and provide a polyester drawn slub yarn and a preparation method thereof.

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

[0008] The invention discloses a method for preparing polyester drawn slub yarn. After polyester melt is extruded through a spinneret, it is cooled by adopting alternating wind pressure. After cooling, the polyester drawn slub yarn is obtained by oiling and winding.

[0009] Alternating cooling air pressure results in alternating cooling effects. When the air pressure is at its maximum within the alternating range, the cooling capacity is maximized, the fiber orientation is high, and the molecular arrangement is relatively regular. Conversely, when the air pressure is low, the molecular arrangement is more chaotic, and the orientation is low. High air pressure results in the greatest cooling air impact on the spinneret nozzle temperature, leading to maximum spinning tension and maximum nozzle stretching. High elongation at break and boiling water shrinkage result in high heat dyeing elongation and deep dyeing. Low elongation at break and boiling water shrinkage result in low heat dyeing elongation and shallow dyeing. Therefore, alternating cooling air pressure creates alternating high and low elongation at break and boiling water shrinkage on continuous fibers. After heat dyeing, the fiber fabric exhibits a pattern of tight, darkly spun sections and lightly spun sections, achieving a fancy, differential shrinkage effect and producing polyester drawn slub yarn.

[0010] The existing technology generally improves the bamboo joint effect by causing a sudden change in the speed of the hot roller, but this will cause problems: first, the tensile tension changes greatly and quickly during the sudden change, which can easily cause the yarn bundle to shake violently on the hot roller, resulting in lint or poor dyeing, or even breakage, and unstable product quality; second, because the hot roller speed needs to change suddenly, the hot roller motor frequency conversion needs to alternately output different currents, and the current changes greatly during the hot roller speed change process, causing serious damage to the equipment. When the speed is abnormal, the sensor cannot accurately detect and alarm, affecting production stability.

[0011] Therefore, the present invention creatively proposes a method for producing a bamboo-like effect in the yarn through alternating changes in the cooling effect after spinning. Stretching and heating are both performed using conventional equipment with a constant speed and temperature regulation, eliminating the problem of uneven stretching. At the same time, the change in the degree of regularity of the molecular arrangement within the fiber due to the change in the cooling effect can achieve different elongations at break and different boiling water shrinkages under the same stretching conditions. This ensures that the yarn is no different from conventional fibers during subsequent weaving. After heated dyeing, the bamboo-like effect will appear. Furthermore, the speed and temperature of the hot roller of the present invention remain constant, avoiding the large changes in tension and current caused by sudden changes in the speed of the hot roller, the generation of harmonic currents, and the inability to accurately detect the yarn bundle. There is no problem of the yarn bundle slipping, shaking, or even breaking on the hot roller.

[0012] As the preferred technical solution:

[0013] According to the method for preparing polyester drawn slub yarn as described above, a spinneret is provided with spinnerets arranged in a plurality of rows in a rhombus shape, and the spinnerets in any two adjacent rows are staggered; the spinneret is divided into two areas A and B with the diagonal line of the rhombus as the dividing line, the spinnerets in area A are cross-section spinnerets, and the spinnerets in area B are circular-section spinnerets.

[0014] The special-shaped hole spinneret of the present invention adopts a design in which half of the holes are cross-shaped and the other half are round. Due to the difference in the specific surface area of the two hole shapes, the cooling effect of the fiber under different wind pressure conditions is significantly different. The fiber specific surface area of the cross-shaped hole is larger, and the alternating wind pressure has a smaller effect on the breaking elongation and boiling water shrinkage of the cross-shaped hole fiber. The fiber specific surface area of the round hole is the smallest, and the alternating wind pressure has a greater effect on the breaking elongation and boiling water shrinkage of the cross-shaped hole fiber. In this way, since two monofilaments with large performance differences appear in the same tow, when the fibers undergo heat treatment steps in subsequent weaving, dyeing and finishing, the fibers will shrink thermally. In this way, the part of the fiber with round holes that has large shrinkage will shrink severely, causing the cross-shaped fiber with small shrinkage in the corresponding part to arch up. Moreover, the part with large shrinkage and the part with small shrinkage appear alternately, so this arching occurs in a regular alternating manner.

[0015] In the above-mentioned method for preparing polyester drawn slubby yarn, the height of the windless zone corresponding to area A on the spinneret is 40-50 mm, and the cooling air pressure is 35-70 Pa; the height of the windless zone corresponding to area B on the spinneret is 50-60 mm, and the cooling air pressure is 20-60 Pa.

[0016] Because the polyester melt is at a very high temperature and relatively fluid for a certain distance after being melted and extruded from the spinneret, a certain distance without cooling air velocity (a "windless zone") is required. The main purpose is to prevent the melt stream from breaking after being disturbed by the cooling air velocity. The conventional ring-blowing cooling method uses a ring-blowing blower device for cooling. The blower is installed in a static pressure chamber. The wind pressure in the static pressure chamber is adjusted by adjusting the air intake to adjust the wind pressure, thereby adjusting the air output of the blower. This cooling method has the effect of uniform cooling. However, the conventional windless zone and ring-blowing cooling method are not applicable to the fiber developed in this study because the same spinneret has two different spinneret orifices. In order to ensure the irregularity and cooling uniformity of the two shaped filament bundles, two different cooling effects are required. That is, the air output on both sides of a circular blower is inconsistent, and the corresponding windless zones of the two filament bundles are inconsistent. The height of the windless zone is adjusted by the height of the silicone sealing rings on both sides of the upper end of the blower (embedded between the blower fairing and the inner liner, which is a prior art).

[0017] A method for preparing polyester drawn slub yarn as described above, wherein one spinning position has 8 to 16 spinnerets, and the spinneret areas A and B on two adjacent spinnerets are positioned opposite to each other;

[0018] Each spinneret is located below a blower. The interior of the blower box is divided into multiple chambers. Each chamber is separated by a semicircular surface of the blower and two vertical plates connected to the two straight edges of the semicircular surface. The orthographic projections of the two vertical plates on the spinneret above them are collinear with the boundary line between the two areas A and B on the spinneret.

[0019] The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct, and chamber B is connected to the second air inlet duct. The first air inlet duct and the second air inlet duct are connected to the main air duct, and air inlet valves are respectively installed on the first air inlet duct and the second air inlet duct.

[0020] In the method for preparing the polyester drawn slub yarn, the number of spinneret holes is 144 to 288; the outer diameter of the spinneret is 95 to 105 mm, and the inner diameter is 80 to 90 mm.

[0021] In the above-mentioned method for preparing polyester drawn slub yarn, the long lobe length of the cross-section spinneret is 0.6 mm, the short lobe length is 0.25 mm, and the widths of the long lobe and the short lobe are both 0.08 mm; the diameter of the circular-section spinneret is 0.16 mm.

[0022] According to the above-mentioned method for preparing polyester drawn slub yarn, the cooling air pressure corresponding to area A on the spinneret is alternately changed between 35-42 Pa and 65-70 Pa, and the time interval for each alternating change is 0.25 s. Specifically, the air pressure is changed from 35-42 Pa to 65-70 Pa, and then changed back to 35-42 Pa after an interval of 0.25 s, and so on. The cooling air pressure corresponding to area B on the spinneret is alternately changed between 20-25 Pa and 55-60 Pa, and the time interval for each alternating change is 0.25 s. Specifically, the air pressure is changed from 20-25 Pa to 55-60 Pa, and then changed back to 20-25 Pa after an interval of 0.25 s, and so on.

[0023] The method for preparing polyester drawn bamboo yarn as described above realizes variable air pressure by changing the opening of the air inlet valve. The air inlet valve is installed at the air inlet of the air inlet duct. The air inlet valve adopts a three-leaf design. Each valve leaf is driven by a driving gear connected to it and a driving gear and a driven gear outside the air inlet duct using a designed driving method to achieve a reciprocating conversion effect. The air inlets of the first air inlet duct and the second air inlet duct are rectangular openings, 150 cm wide and 15 cm high; the air inlet valve consists of a valve body and a valve leaf located in the valve body, there are 3 valve leaves, the width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet, that is, the width of each valve leaf is 150 cm and the height is 5 cm; a drive shaft is welded to each valve leaf, the axial direction of the drive shaft is parallel to the width direction of the valve leaf, both ends of the drive shaft extend to the outside of the first air inlet duct and the second air inlet duct, and one end is connected to a fixed bracket (the fixed bracket is set on the outer wall of the first air inlet duct and the second air inlet duct), and the other end is connected to a driving gear, so that the drive shaft can rotate on the fixed bracket , causing the valve leaf to rotate, thus realizing the opening and closing of the valve leaf, and the driving gears connected to each valve leaf are meshed with each other; the lowest driving gear is meshed with the first driven gear, and is also connected to the second driven gear through a toothed belt, and a driving gear is installed between the first driven gear and the second driven gear. The driving gear is a gear with few teeth, and the other gears are complete gears, and the teeth on the gear with few teeth are set in the 1 / 12 area of the gear circumference; the diameters of the driving gear, driven gear and driving gear are equal, all 5cm; the driving gear is driven by a motor and a reduction gear box, and when the driving gear rotates until the gear teeth are close to the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear are meshed with each other; such as Figure 4 As shown, when all the valve leaves are completely vertical, the air inlet valve is fully closed; when all the valve leaves are completely horizontal, the air inlet valve is fully open; the cooling air volume of the air duct is adjusted by changing the rotation degree of the valve leaves. As the driving gear continues to rotate in the same direction, the position of the valve leaves will change alternately, thereby realizing the alternating change of the cooling air volume in the air duct.

[0024] The working principle of the change in the opening of the air inlet valve: first, manually set an air valve opening, that is, a constant air inlet pressure and air valve card degree, for example, the valve leaf angle is 30°, and with this as the starting point, when the driving gear rotates counterclockwise, it first drives the first driven gear to rotate 30° clockwise. Because the driving gear is engaged with the first driven gear, the driving gear rotates counterclockwise and drives all the other driving gears to rotate 30° at the same time, so that the valve leaf is closed 30°, and the driving gear continues to rotate and disengages the teeth of the first driven gear. After continuing to rotate, the driving gear will engage with the second driven gear, driving the first driven gear to rotate clockwise. Since the first driven gear and the driving gear are connected with a toothed belt, they rotate clockwise 30° synchronously, so that all the valve leaf teeth open 30° again. As the driving gear keeps rotating, the valve leaf will appear to open 30° and close 30° regularly.

[0025] The present invention also provides a polyester drawn slub yarn prepared by the preparation method described above, wherein the specifications of the polyester drawn slub yarn are 83-168 dtex / 128-288 f; the segment length of the polyester drawn slub yarn is 10-12 m, the breaking strength is greater than 3.8 cN / dtex, the breaking elongation is 35.0±3.0%, and the boiling water shrinkage is 15.0±1.0%.

[0026] Beneficial effects:

[0027] (1) By using alternating wind pressure, the present invention can make the breaking elongation and boiling water shrinkage of continuous fibers alternate between large and small. After the fiber fabric is thermally dyed, the fabric will have a section where it shrinks tightly and is darkly dyed, and a section where it shrinks less and is lightly dyed, thereby achieving the effect of fancy differential shrinkage.

[0028] (2) The present invention produces a bamboo knot effect on the silk by alternating changes in the cooling effect after spinning and spraying, and the bamboo knot effect is better, and the bamboo knot effect is even better after heating and dyeing.

[0029] (3) The present invention can adjust the wind pressure in the air duct according to the different fiber cross-sections, so that the two types of heterogeneous fibers can be subjected to their respective appropriate cooling wind pressures. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the cross section of the spinneret of the present invention; in the figure, S is the length of the short lobe, L is the length of the long lobe, and D is the width of the short lobe;

[0031] Figure 2 Schematic diagram of the distribution of spinneret holes on the spinneret of the present invention;

[0032] Figure 3 Schematic diagram of the distribution of the air cylinder and chamber in the bellows of the present invention;

[0033] Figure 4Schematic diagram of the use of the air valve of the present invention; in the figure, a is a schematic diagram of the air valve when it is fully open, b is a schematic diagram of the air valve when it is closed, and the arrow in the figure indicates the direction of the incoming air;

[0034] Figure 5 Schematic diagram of the structure of the air valve of the present invention; in the figure, the arrow indicates the direction of the air inlet;

[0035] Among them, 1-valve leaf, 2-driving gear, 3-first driven gear, 4-second driven gear, 5-toothed belt, 6-driving gear, 7-first air inlet duct, 8-second air inlet duct, 9-vertical plate, 10-air cylinder. DETAILED DESCRIPTION

[0036] 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.

[0037] The test methods for the relevant performance indicators in the following embodiments are as follows:

[0038] Breaking strength and elongation at break: The polyester drawn bamboo yarn prepared in each embodiment was used as a sample, and then the sample was tested using a YG023B-Ⅱ fully automatic single yarn strength machine according to the standard GB / T14344-2022 "Test method for tensile properties of chemical fiber filaments"; the specific process is: first, 20 1m polyester drawn bamboo yarns were continuously taken from a silk cake wound in each embodiment as samples, and then they were humidified at a temperature of 20°C and a humidity of 65% for 4 hours, and then the humidified samples were stretched until they broke using a fully automatic single yarn strength machine. At the same time, when 20 samples were tested, the force sensor drew a strength-elongation curve through the data collection system, and the average value was taken after data processing to obtain the breaking strength and elongation at break; wherein, the upper and lower clamps determined that the clamping length was 500mm, the manipulator clamped the sample with a pre-tension of 0.05cN / dtex, and the lower clamp set the test speed to 500mm / min.

[0039] Boiling Water Shrinkage: The polyester drawn slub yarns prepared in each embodiment were tested according to the skein method in accordance with GB / T 6505-2017, Test Method for Thermal Shrinkage of Chemical Fiber Filaments (After Treatment). The specific process is as follows: 10 polyester drawn slub yarns prepared in the same embodiment were first taken as samples. Subsequently, under the specified test conditions, the 10 samples were treated with boiling water. The changes in the lengths of the 10 samples before and after treatment were measured and recorded. The percentage of the length of each sample to the original yarn length was calculated to obtain the boiling water shrinkage of each sample. Finally, the average value was calculated as the boiling water shrinkage.

[0040] Example 1

[0041] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0042] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 69.5% by mass) with an intrinsic viscosity of 0.61 dL / g was extruded through a spinneret and cooled by alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 291°C, the spinning temperature was 305°C, the number of turns of the first hot roller was 4.5, the temperature of the first hot roller was 85°C, the number of turns of the second hot roller was 5.5, the temperature of the second hot roller was 127°C, and the winding speed was 3400 m / min;

[0043] In the above process of preparing polyester drawn slub yarn, one spinning position has a total of 8 spinnerets;

[0044] like Figure 2 As shown, the spinneret in each spinneret assembly is provided with 14 rows of spinneret holes arranged in a diamond shape, and the spinneret holes in any two adjacent rows are staggered; the number of spinneret holes is 288; the outer diameter of the spinneret is 95 mm and the inner diameter is 80 mm;

[0045] The spinneret is divided into two areas A and B with the diagonal line of the rhombus as the dividing line; the areas A and B of the spinnerets on two adjacent spinneret assemblies are located opposite to each other;

[0046] like Figure 1 As shown, the spinneret in area A is a cross-section spinneret, the long lobe length L of the cross-section spinneret is 0.6 mm, the short lobe length S is 0.25 mm, and the long lobe width and short lobe width D are both 0.08 mm;

[0047] The spinneret in area B is a circular cross-section spinneret with a diameter of 0.16 mm;

[0048] like Figure 3 As shown, there is a blower 10 below each spinning assembly. The interior of the wind box where the blower 10 is located is divided into 9 chambers. Each chamber is separated by a semi-circumferential surface of the blower 10 and two vertical plates 9 connected to the two straight sides of the semi-circumferential surface. The orthographic projections of the two vertical plates 9 on the spinneret above them are collinear with the boundary line between the two areas A and B on the spinneret.

[0049] The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct 7, and chamber B is connected to the second air inlet duct 8. The first air inlet duct 7 and the second air inlet duct 8 are connected to the main air duct. The first air inlet duct 7 and the second air inlet duct 8 are respectively installed with air inlet valves.

[0050] The air inlets of the first air inlet duct 7 and the second air inlet duct 8 are rectangular openings of 150 cm (width) × 15 cm (height), such as Figure 5 As shown, the air inlet valve consists of a valve body and a valve leaf 1 located in the valve body. There are 3 valve leaves 1. The width of each valve leaf 1 is equal to the width of the air inlet, and the height of each valve leaf 1 is 1 / 3 of the height of the air inlet. A drive shaft is welded to each valve leaf 1. The axial direction of the drive shaft is parallel to the width direction of the valve leaf 1. Both ends of the drive shaft extend to the outside of the first air inlet duct 7 and the second air inlet duct 8, and one end is connected to the fixed bracket, and the other end is connected to a drive gear 2. The drive gear 2 connected to each valve leaf 1 is meshed with each other; the lowest drive gear 2 is meshed with the first driven gear 3, and is also connected to the second driven gear 4 through a toothed belt 5. A driving gear 6 is installed between the first driven gear 3 and the second driven gear 4. The driving gear 6 is a gear with fewer teeth, and the teeth on the gear with fewer teeth are arranged in an area of 1 / 12 of the gear circumference; the diameters of the driving gear 2, the driven gear and the driving gear 6 are equal; the driving gear 6 is driven by a motor and a reduction gear box. When the driving gear 6 rotates until the teeth approach the first driven gear or the second driven gear, the driving gear 6 and the first driven gear or the second driven gear are meshed with each other; as the driving gear 6 continues to rotate in the same direction, the position of the valve leaf 1 will change alternately, thereby achieving an alternating change in the cooling air volume in the air duct 10;

[0051] The height of the windless zone corresponding to area A on the spinneret is 40 mm, and the wind pressure of the air duct 10 corresponding to area A on the spinneret is alternately changed between 35 Pa and 65 Pa, with a time interval of 0.25 s for each alternation;

[0052] The height of the windless zone corresponding to area B on the spinneret is 50 mm, and the wind pressure of the air duct 10 corresponding to area B on the spinneret is alternately changed between 20 Pa and 55 Pa, with a time interval of 0.25 s for each alternation.

[0053] The final polyester drawn slub yarn has a specification of 83dtex / 144f, a segment length of 10m, a breaking strength of 4cN / dtex, an elongation at break of 34.1%, and a boiling water shrinkage of 14.1%.

[0054] Example 2

[0055] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0056] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 70% by mass) with an intrinsic viscosity of 0.613 dL / g was extruded through a spinneret and cooled using alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 290°C, the spinning temperature was 304°C, the number of turns of the first hot roller was 4.5, the temperature of the first hot roller was 84°C, the number of turns of the second hot roller was 5.5, the temperature of the second hot roller was 126°C, and the winding speed was 3400 m / min;

[0057] In the above process of preparing polyester drawn slub yarn, one spinning position has a total of 12 spinnerets;

[0058] Each spinneret assembly has 18 rows of spinneret holes arranged in a diamond pattern, with any two adjacent rows of spinneret holes staggered. The number of spinneret holes is 256. The outer diameter of the spinneret is 104 mm and the inner diameter is 90 mm.

[0059] The spinneret is divided into two areas A and B with the diagonal line of the rhombus as the dividing line; the areas A and B of the spinnerets on two adjacent spinneret assemblies are located opposite to each other;

[0060] The spinneret in area A is a cross-section spinneret with a long lobe length of 0.6 mm, a short lobe length of 0.25 mm, and a width of 0.08 mm for both the long and short lobe.

[0061] The spinneret in area B is a circular cross-section spinneret with a diameter of 0.16 mm;

[0062] Each spinneret assembly has a corresponding blower. The interior of the blower box is divided into 13 chambers. Each chamber is separated by a semi-circumferential surface of the blower and two vertical plates connected to the two straight edges of the semi-circumferential surface. The orthographic projections of the two vertical plates on the spinneret above them are collinear with the boundary line between the two areas A and B on the spinneret.

[0063] The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct, and chamber B is connected to the second air inlet duct. The first air inlet duct and the second air inlet duct are connected to the main air duct. The first air inlet duct and the second air inlet duct are respectively installed with an air inlet valve;

[0064] The air inlets of the first air inlet duct and the second air inlet duct are rectangular openings of 150 cm (width) × 15 cm (height). The air inlet valve consists of a valve body and a valve leaf located in the valve body. There are 3 valve leaves. The width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet. A drive shaft is welded to each valve leaf. The axial direction of the drive shaft is parallel to the width direction of the valve leaf. Both ends of the drive shaft extend to the outside of the first air inlet duct and the second air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to a drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is engaged with the first driven gear. At the same time, it is also connected to the second driven gear through a toothed belt. A driving gear is installed between the first driven gear and the second driven gear. The driving gear is a gear with fewer teeth, and the teeth on the gear with fewer teeth are set in the 1 / 12 area of the gear circumference. The diameters of the driving gear, the driven gear and the driving gear are equal. The driving gear is driven by a motor and a reduction gear. When the driving gear rotates until the teeth approach the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear engage with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving alternating changes in the cooling air volume in the air duct.

[0065] The height of the windless zone corresponding to area A on the spinneret is 45 mm, and the cooling air pressure corresponding to area A on the spinneret is alternately changed between 35 Pa and 68 Pa, with a time interval of 0.25 s for each alternation;

[0066] The height of the windless zone corresponding to area B on the spinneret is 55 mm, and the cooling air pressure corresponding to area B on the spinneret is alternately changed between 20 Pa and 58 Pa, with a time interval of 0.25 s for each alternation.

[0067] The final polyester drawn slub yarn has a specification of 83dtex / 128f, a segment length of 11m, a breaking strength of 3.95cN / dtex, an elongation at break of 35.6%, and a boiling water shrinkage of 14.5%.

[0068] Example 3

[0069] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0070] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 70.5% by mass) with an intrinsic viscosity of 0.615 dL / g was extruded through a spinneret and cooled by alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 294°C, the spinning temperature was 307°C, the number of turns of the first hot roller was 5.5, the temperature of the first hot roller was 98°C, the number of turns of the second hot roller was 6.5, the temperature of the second hot roller was 133°C, and the winding speed was 3500 m / min;

[0071] In the above process of preparing polyester drawn slub yarn, one spinning position has a total of 16 spinnerets;

[0072] Each spinneret assembly has 20 rows of spinneret holes arranged in a diamond shape, with any two adjacent rows of spinneret holes staggered. The spinneret has 288 holes. The outer diameter of the spinneret is 105 mm and the inner diameter is 90 mm.

[0073] The spinneret is divided into two areas A and B with the diagonal line of the rhombus as the dividing line; the areas A and B of the spinnerets on two adjacent spinneret assemblies are located opposite to each other;

[0074] The spinneret in area A is a cross-section spinneret with a long lobe length of 0.6 mm, a short lobe length of 0.25 mm, and a width of 0.08 mm for both the long and short lobe.

[0075] The spinneret in area B is a circular cross-section spinneret with a diameter of 0.16 mm;

[0076] Each spinneret is located below a corresponding blower. The interior of the blower box is divided into 17 chambers. Each chamber is separated by a semicircular surface of the blower and two vertical plates connected to the two straight edges of the semicircular surface. The orthographic projections of the two vertical plates on the spinneret above them are collinear with the boundary line between areas A and B on the spinneret.

[0077] The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct, and chamber B is connected to the second air inlet duct. The first air inlet duct and the second air inlet duct are connected to the main air duct. The first air inlet duct and the second air inlet duct are respectively installed with an air inlet valve;

[0078] The air inlets of the first air inlet duct and the second air inlet duct are rectangular openings of 150 cm (width) × 15 cm (height). The air inlet valve consists of a valve body and a valve leaf located in the valve body. There are 3 valve leaves. The width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet. A drive shaft is welded to each valve leaf. The axial direction of the drive shaft is parallel to the width direction of the valve leaf. Both ends of the drive shaft extend to the outside of the first air inlet duct and the second air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to a drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is engaged with the first driven gear. At the same time, it is also connected to the second driven gear through a toothed belt. A driving gear is installed between the first driven gear and the second driven gear. The driving gear is a gear with fewer teeth, and the teeth on the gear with fewer teeth are set in the 1 / 12 area of the gear circumference. The diameters of the driving gear, the driven gear and the driving gear are equal. The driving gear is driven by a motor and a reduction gear. When the driving gear rotates until the teeth approach the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear engage with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving alternating changes in the cooling air volume in the air duct.

[0079] The height of the windless zone corresponding to area A on the spinneret is 50 mm, and the cooling air pressure corresponding to area A on the spinneret is alternately changed between 40 Pa and 70 Pa, with a time interval of 0.25 s for each alternation;

[0080] The height of the windless zone corresponding to area B on the spinneret is 60 mm, and the cooling air pressure corresponding to area B on the spinneret is alternately changed between 25 Pa and 60 Pa, with a time interval of 0.25 s for each alternation.

[0081] The final polyester drawn slub yarn has a specification of 168dtex / 288f, a segment length of 12m, a breaking strength of 3.9cN / dtex, an elongation at break of 36.4%, and a boiling water shrinkage of 15.4%.

[0082] Example 4

[0083] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0084] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 70% by mass) with an intrinsic viscosity of 0.62 dL / g was extruded through a spinneret and cooled using alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 293°C, the spinning temperature was 305°C, the number of turns of the first hot roller was 4.5, the temperature of the first hot roller was 85°C, the number of turns of the second hot roller was 5.5, the temperature of the second hot roller was 126°C, and the winding speed was 3400 m / min;

[0085] In the above process of preparing polyester drawn slub yarn, a total of 10 spinnerets are provided in one spinning position;

[0086] Each spinneret assembly has 16 rows of spinneret holes arranged in a diamond shape, with any two adjacent rows of spinneret holes staggered. The number of spinneret holes is 256. The outer diameter of the spinneret is 95 mm and the inner diameter is 85 mm.

[0087] The spinneret is divided into two areas A and B with the diagonal line of the rhombus as the dividing line; the areas A and B of the spinnerets on two adjacent spinneret assemblies are located opposite to each other;

[0088] The spinneret in area A is a cross-section spinneret with a long lobe length of 0.6 mm, a short lobe length of 0.25 mm, and a width of 0.08 mm for both the long and short lobe.

[0089] The spinneret in area B is a circular cross-section spinneret with a diameter of 0.16 mm;

[0090] Each spinneret is located below a corresponding blower. The interior of the blower box is divided into 11 chambers. Each chamber is separated by a semicircular surface of the blower and two vertical plates connected to the two straight edges of the semicircular surface. The orthographic projections of the two vertical plates on the spinneret above them are collinear with the boundary line between areas A and B on the spinneret.

[0091] The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct, and chamber B is connected to the second air inlet duct. The first air inlet duct and the second air inlet duct are connected to the main air duct. The first air inlet duct and the second air inlet duct are respectively installed with an air inlet valve;

[0092] The air inlets of the first air inlet duct and the second air inlet duct are rectangular openings of 150 cm (width) × 15 cm (height). The air inlet valve consists of a valve body and a valve leaf located in the valve body. There are 3 valve leaves. The width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet. A drive shaft is welded to each valve leaf. The axial direction of the drive shaft is parallel to the width direction of the valve leaf. Both ends of the drive shaft extend to the outside of the first air inlet duct and the second air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to a drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is engaged with the first driven gear. At the same time, it is also connected to the second driven gear through a toothed belt. A driving gear is installed between the first driven gear and the second driven gear. The driving gear is a gear with fewer teeth, and the teeth on the gear with fewer teeth are set in the 1 / 12 area of the gear circumference. The diameters of the driving gear, the driven gear and the driving gear are equal. The driving gear is driven by a motor and a reduction gear. When the driving gear rotates until the teeth approach the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear engage with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving alternating changes in the cooling air volume in the air duct.

[0093] The height of the windless zone corresponding to area A on the spinneret is 45 mm, and the cooling air pressure corresponding to area A on the spinneret is alternately changed between 35 Pa and 70 Pa, with a time interval of 0.25 s for each alternation;

[0094] The height of the windless zone corresponding to area B on the spinneret is 55 mm, and the cooling air pressure corresponding to area B on the spinneret is alternately changed between 25 Pa and 60 Pa, with a time interval of 0.25 s for each alternation.

[0095] The final polyester drawn slub yarn has a specification of 83dtex / 128f, a segment length of 11m, a breaking strength of 3.95cN / dtex, an elongation at break of 35.9%, and a boiling water shrinkage of 14.5%.

[0096] Example 5

[0097] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0098] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 70% by mass) with an intrinsic viscosity of 0.625 dL / g was extruded through a spinneret and cooled using alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 293°C, the spinning temperature was 306°C, the number of turns of the first hot roller was 5.5, the temperature of the first hot roller was 97°C, the number of turns of the second hot roller was 6.5, the temperature of the second hot roller was 133°C, and the winding speed was 3500 m / min;

[0099] In the above process of preparing polyester drawn slub yarn, one spinning position has a total of 12 spinnerets;

[0100] Each spinneret assembly has 18 rows of spinneret holes arranged in a diamond shape, with any two adjacent rows of spinneret holes staggered. The number of spinneret holes is 288. The outer diameter of the spinneret is 105 mm and the inner diameter is 90 mm.

[0101] The spinneret is divided into two areas A and B with the diagonal line of the rhombus as the dividing line; the areas A and B of the spinnerets on two adjacent spinneret assemblies are located opposite to each other;

[0102] The spinneret in area A is a cross-section spinneret with a long lobe length of 0.6 mm, a short lobe length of 0.25 mm, and a width of 0.08 mm for both the long and short lobe.

[0103] The spinneret in area B is a circular cross-section spinneret with a diameter of 0.16 mm;

[0104] Each spinneret assembly has a corresponding blower. The interior of the blower box is divided into 13 chambers. Each chamber is separated by a semi-circumferential surface of the blower and two vertical plates connected to the two straight edges of the semi-circumferential surface. The orthographic projections of the two vertical plates on the spinneret above them are collinear with the boundary line between the two areas A and B on the spinneret.

[0105] The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct, and chamber B is connected to the second air inlet duct. The first air inlet duct and the second air inlet duct are connected to the main air duct. The first air inlet duct and the second air inlet duct are respectively installed with an air inlet valve;

[0106] The air inlets of the first air inlet duct and the second air inlet duct are rectangular openings of 150 cm (width) × 15 cm (height). The air inlet valve consists of a valve body and a valve leaf located in the valve body. There are 3 valve leaves. The width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet. A drive shaft is welded to each valve leaf. The axial direction of the drive shaft is parallel to the width direction of the valve leaf. Both ends of the drive shaft extend to the outside of the first air inlet duct and the second air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to a drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is engaged with the first driven gear. At the same time, it is also connected to the second driven gear through a toothed belt. A driving gear is installed between the first driven gear and the second driven gear. The driving gear is a gear with fewer teeth, and the teeth on the gear with fewer teeth are set in the 1 / 12 area of the gear circumference. The diameters of the driving gear, the driven gear and the driving gear are equal. The driving gear is driven by a motor and a reduction gear. When the driving gear rotates until the teeth approach the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear engage with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving alternating changes in the cooling air volume in the air duct.

[0107] The height of the windless zone corresponding to area A on the spinneret is 48 mm, and the cooling air pressure corresponding to area A on the spinneret is alternately changed between 42 Pa and 70 Pa, with a time interval of 0.25 s for each alternation;

[0108] The height of the windless zone corresponding to area B on the spinneret is 58 mm, and the cooling air pressure corresponding to area B on the spinneret is alternately changed between 20 Pa and 58 Pa, with a time interval of 0.25 s for each alternation.

[0109] The final polyester drawn slub yarn has a specification of 160dtex / 288f, a segment length of 12m, a breaking strength of 3.9cN / dtex, an elongation at break of 36.7%, and a boiling water shrinkage of 15.9%.

[0110] Example 6

[0111] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0112] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 70% by mass) with an intrinsic viscosity of 0.625 dL / g was extruded through a spinneret and cooled using alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 293°C, the spinning temperature was 306°C, the number of turns of the first hot roller was 5.5, the temperature of the first hot roller was 97°C, the number of turns of the second hot roller was 6.5, the temperature of the second hot roller was 133°C, and the winding speed was 3500 m / min;

[0113] In the above process of preparing polyester drawn slub yarn, one spinning position has a total of 12 spinnerets;

[0114] Each spinneret has 18 rows of circular-section spinnerets arranged in a diamond pattern, with any two adjacent rows of spinnerets staggered. The spinneret has 288 holes. The outer diameter of the spinneret is 105 mm, the inner diameter is 90 mm, and the diameter of the circular-section spinneret is 0.16 mm.

[0115] There is a wind tube under each spinning assembly, and an air inlet valve is installed on the air inlet duct of the wind tube; the air inlet of the air inlet duct is a rectangular opening of 150cm (width) × 15cm (height), and the air inlet valve consists of a valve body and a valve leaf located in the valve body. There are 3 valve leaves, and the width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet. A drive shaft is welded on each valve leaf, and the axial direction of the drive shaft is parallel to the width direction of the valve leaf. Both ends of the drive shaft extend to the outside of the air inlet duct, and one end is connected to a fixed bracket, and the other end is connected to a drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is connected to the first The driven gear is meshed and is also connected to the second driven gear via a toothed belt. A driving gear is installed between the first and second driven gears. The driving gear is a gear with fewer teeth, and the teeth on the gear with fewer teeth are arranged in an area of 1 / 12 of the gear circumference. The diameters of the driving gear, the driven gear, and the driving gear are equal. The driving gear is driven by a motor and a reduction gear box. When the driving gear rotates until the teeth approach the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear mesh with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving an alternating change in the cooling air volume in the air duct.

[0116] The height of the windless zone is 48 mm, and the cooling air pressure changes alternately between 38 Pa and 68 Pa, with a time interval of 0.25 s for each alternation.

[0117] The final polyester drawn slub yarn has a specification of 160dtex / 288f, a segment length of 10m, a breaking strength of 4.18cN / dtex, an elongation at break of 39.2%, and a boiling water shrinkage of 18.0%.

[0118] Example 7

[0119] A method for preparing polyester drawn slub yarn, comprising the following steps:

[0120] A polyester melt (formed by polycondensation of PTA and EG, with PTA accounting for 70% by mass) with an intrinsic viscosity of 0.625 dL / g was extruded through a spinneret and cooled using alternating wind pressure. After cooling, it was oiled and wound to produce polyester drawn slub yarn; wherein, the box temperature was 293°C, the spinning temperature was 306°C, the number of turns of the first hot roller was 5.5, the temperature of the first hot roller was 97°C, the number of turns of the second hot roller was 6.5, the temperature of the second hot roller was 133°C, and the winding speed was 3500 m / min;

[0121] In the above process of preparing polyester drawn slub yarn, one spinning position has a total of 12 spinnerets;

[0122] Each spinneret has 18 rows of cross-section spinnerets arranged in a diamond pattern, with any two adjacent rows of spinnerets staggered. The spinneret has 288 holes. The outer diameter of the spinneret is 105 mm, and the inner diameter is 90 mm. The long lobe of the cross-section spinneret is 0.6 mm long, the short lobe is 0.25 mm long, and the width of both lobe and short lobe is 0.08 mm.

[0123] There is a wind tube under each spinning assembly, and an air inlet valve is installed on the air inlet duct of the wind tube; the air inlet of the air inlet duct is a rectangular opening of 150cm (width) × 15cm (height), and the air inlet valve consists of a valve body and a valve leaf located in the valve body. There are 3 valve leaves, and the width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet. A drive shaft is welded on each valve leaf, and the axial direction of the drive shaft is parallel to the width direction of the valve leaf. Both ends of the drive shaft extend to the outside of the air inlet duct, and one end is connected to a fixed bracket, and the other end is connected to a drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is connected to the first The driven gear is meshed and is also connected to the second driven gear via a toothed belt. A driving gear is installed between the first and second driven gears. The driving gear is a gear with fewer teeth, and the teeth on the gear with fewer teeth are arranged in an area of 1 / 12 of the gear circumference. The diameters of the driving gear, the driven gear, and the driving gear are equal. The driving gear is driven by a motor and a reduction gear box. When the driving gear rotates until the teeth approach the first driven gear or the second driven gear, the driving gear and the first driven gear or the second driven gear mesh with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving an alternating change in the cooling air volume in the air duct.

[0124] The height of the windless zone is 47 mm, and the cooling air pressure changes alternately between 41 Pa and 60 Pa, with a time interval of 0.25 s for each alternation.

[0125] The final polyester drawn slub yarn has a specification of 160dtex / 288f, a segment length of 11m, a breaking strength of 3.73cN / dtex, an elongation at break of 28.4%, and a boiling water shrinkage of 11.4%.

Claims

1. A method for preparing polyester drawn slub yarn, characterized in that: After the polyester melt is extruded through the spinneret, it is cooled by alternating wind pressure, and then oiled and wound to produce polyester drawn slub yarn. The spinneret is provided with spinnerets arranged in multiple rows of diamond shapes, and the spinnerets in any two adjacent rows are staggered; the spinneret is divided into two areas A and B with the diagonal line of the diamond shape as the dividing line, the spinnerets in area A are cross-section spinnerets, and the spinnerets in area B are circular-section spinnerets; The cooling air pressure corresponding to area A on the spinneret is alternately changed between 35~42Pa and 65~70Pa, and the time interval of each alternation is 0.25s; the cooling air pressure corresponding to area B on the spinneret is alternately changed between 20~25Pa and 55~60Pa, and the time interval of each alternation is 0.25s; There are 8 to 16 spinnerets in one spinning position, and the A area and B area of the spinneret on two adjacent spinnerets are in opposite positions; Each spinneret is located below a blower. The interior of the blower box is divided into multiple chambers. Each chamber is separated by a semicircular surface of the blower and two vertical plates connected to the two straight edges of the semicircular surface. The orthographic projections of the two vertical plates on the spinneret above them are collinear with the boundary line between the two areas A and B on the spinneret. The chamber corresponding to the A area of the spinneret is recorded as chamber A, and the chamber corresponding to the B area of the spinneret is recorded as chamber B. Chamber A is connected to the first air inlet duct, and chamber B is connected to the second air inlet duct. The first air inlet duct and the second air inlet duct are connected to the main air duct. The first air inlet duct and the second air inlet duct are respectively installed with an air inlet valve; The air inlet valve consists of a valve body and valve leaves located in the valve body. There are three valve leaves, the width of each valve leaf is equal to the width of the air inlet, and the height of each valve leaf is 1 / 3 of the height of the air inlet; a drive shaft is welded to each valve leaf, the axial direction of the drive shaft is parallel to the width direction of the valve leaf, both ends of the drive shaft extend to the outside of the first air inlet duct and the second air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to the drive gear, which is engaged with the drive gear connected to each valve leaf; the lowest drive gear is engaged with the first driven gear, and is also connected to the second driven gear through a toothed belt. A driving gear is installed between the first driven gear and the second driven gear. The driving gear is a small-tooth gear, and the teeth on the small-tooth gear are set in the 1 / 12 area of the gear circumference; The diameters of the driving gear, the driven gear, and the active gear are equal; the active gear is driven by a motor and a reduction gear box, and when the active gear rotates until the gear teeth approach the first driven gear or the second driven gear, the active gear and the first driven gear or the second driven gear mesh with each other; As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby achieving alternating changes in the cooling air volume in the air duct.

2. The method for preparing polyester drawn slub yarn according to claim 1, wherein: The height of the windless zone corresponding to area A on the spinneret is 40~50mm, and the cooling air pressure is 35~70Pa; the height of the windless zone corresponding to area B on the spinneret is 50~60mm, and the cooling air pressure is 20~60Pa.

3. The method for preparing polyester drawn slub yarn according to claim 2, wherein: The number of spinneret holes is 144~288; the outer diameter of the spinneret is 95~105mm, and the inner diameter is 80~90mm.

4. The method for preparing polyester drawn slub yarn according to claim 3, wherein: The long lobe length of the cross-section spinneret is 0.6 mm, the short lobe length is 0.25 mm, and the width of the long lobe and the short lobe are both 0.08 mm; the diameter of the circular-section spinneret is 0.16 mm.

5. A polyester drawn slub yarn obtained by the preparation method according to claim 4, characterized in that: The specifications of the polyester drawn slub yarn are 83~168dtex / 128~288f; the breaking strength of the polyester drawn slub yarn is greater than 3.8cN / dtex, the elongation at break is 35.0±3.0%, and the boiling water shrinkage is 15.0±1.0%.

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