Dacron drafting slub yarn and preparation method thereof

Abstract

The invention belongs to the technical field of polyester filament yarns, and relates to a polyester drafting slub yarn and a preparation method thereof, and the preparation method comprises the following steps: extruding a polyester melt through a spinneret plate, cooling by adopting alternative wind pressure, and oiling and winding after cooling to obtain the polyester drafting slub yarn, the pitch length of the prepared polyester drafting slub yarn is 2-2.5 m, the breaking strength is greater than 3.8 cN / dtex, the elongation at break is 35.0 + / -3.0%, and the boiling water shrinkage is 15.0 + / -1.0%. According to the method disclosed by the invention, by using the alternately changed wind pressure, the breaking elongation and the boiling water shrinkage on continuous fibers can be alternated in a manner that one section is large and one section is small, and the fabric after thermal dyeing of the fiber fabric has the conditions that one section shrinks tightly and is deep in dyeing, and the other section shrinks less and is light in dyeing, so that the fancy different shrinkage effect is achieved.

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 continuous growth of the domestic economic level and the people's pursuit of a better quality of life, consumers have increasingly higher requirements for polyester fabrics, especially in terms of fabric texture and functionality, which has also prompted polyester products to develop in a differentiated direction, and various innovative products have emerged. Among them, fabrics woven from polyester drawn bamboo yarn can show unique color stripes after dyeing. This feature is deeply favored by the market and customers, and is therefore widely used.

[0003] However, the existing technology has problems such as poor slub effect and unstable production. For example, in the literature (Discussion on the production process of 82.5dtex / 144f FDY slub yarn [J]. Polyester Industry. 2018, 31(2):37-39), slub yarn can be produced by replacing the hot roller with a hot roller with equidistant slots at the head end of the hot roller. However, since the hot roller for stretching the filament bundle is equidistantly slotted, it is easy to make the filament bundle suddenly thick or thin locally, affecting the subsequent weaving efficiency and the slub effect of the fabric.

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

[0005] Therefore, a polyester drawn slub yarn and a preparation method thereof are needed to solve the above-mentioned 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] 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 slubby yarns. After polyester melt is extruded through a spinneret, it is cooled by adopting alternating wind pressure, and after cooling, the polyester drawn slubby yarns are obtained by oiling and winding.

[0009] When the cooling air pressure changes alternately, the cooling effect of spinning will change alternately. When the air pressure is at the maximum value of the alternating change range, the cooling amount is the largest. At this time, the fiber orientation is high and the molecular arrangement is relatively regular. On the contrary, when the air pressure is small, the molecular arrangement is more disordered and the orientation is low. When the air pressure is large, the cooling air has the greatest impact on the temperature of the spinneret nozzle, the spinning tension is the largest, resulting in the maximum stretching of the nozzle, and the elongation at break and the boiling water shrinkage should be large, and vice versa. When the elongation at break and the boiling water shrinkage are large, the fiber fabric shrinks greatly and dyes dark during thermal dyeing. When the elongation at break and the boiling water shrinkage are small, the fiber fabric shrinks little and dyes light during thermal dyeing. Therefore, the alternating cooling air pressure makes the elongation at break and the boiling water shrinkage appear in the continuous fiber. After thermal dyeing, the fiber fabric will shrink tightly and dye dark, and shrink less and dye light, so as to achieve the effect of fancy shrinkage and obtain polyester drawn bamboo 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: one is that 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 output different currents alternately, and the current changes greatly during the change of the hot roller speed, causing great damage to the equipment. When the speed is abnormal, the sensor cannot perform accurate detection and alarm, affecting production stability.

[0011] Therefore, the present invention creatively proposes a method of producing bamboo effect in the silk through alternating changes in cooling effect after spinning and spraying. The stretching and heating are all produced using conventional uniform speed and temperature-controlled equipment, and there is no uneven stretching. At the same time, due to the change in the cooling effect, the regularity of the molecular arrangement inside the fiber changes, which can achieve different elongation at break and different boiling water shrinkage under the same stretching conditions, so that it can ensure that there is no difference with conventional fibers in the subsequent weaving, and bamboo effect will appear after heating and dyeing. In addition, the speed and temperature of the hot roller of the present invention are constant, which also avoids the large tension change, large current change, harmonic current generation, and inability to accurately detect caused by the sudden change of the hot roller speed. There is no problem of the silk bundle slipping or shaking on the hot roller or even breaking.

[0012] As the preferred technical solution:

[0013] In the method for preparing polyester drawn slubby 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 regions A and B with the diagonal line of the rhombus as the dividing line, the spinnerets in region A are cross-section spinnerets, and the spinnerets in region 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 elongation at break and the boiling water shrinkage of the fiber of the cross-shaped hole. The fiber specific surface area of ​​the round hole is the smallest, and the alternating wind pressure has a greater effect on the elongation at break and the boiling water shrinkage of the fiber of the cross-shaped hole. In this way, since two monofilaments with large performance differences appear in the same tow, when the fiber undergoes heat treatment in the subsequent weaving, dyeing and finishing processes, the fiber will produce thermal shrinkage, so that the part of the round hole fiber with large shrinkage in the fiber will shrink severely, causing the cross-shaped fiber with small shrinkage corresponding to it to arch up, and the part with large shrinkage and the part with small shrinkage appear alternately, so that the arching occurs regularly and alternately.

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

[0016] Because the temperature of the polyester melt is very high within a certain distance after it is melted and extruded from the spinneret, and it is in a state of relatively good fluidity, it is necessary to set a certain distance without cooling wind speed (windless zone), the main purpose of which is to prevent the melt stream from being broken after being disturbed by the cooling wind speed. The conventional ring-blowing cooling method is to use a ring-blowing blower device for cooling. The blower is installed in the static pressure bin. The wind pressure of the static pressure bin is adjusted by adjusting the air intake of the static pressure bin, so as to achieve the effect of adjusting the air volume of the blower. This cooling method has a uniform cooling effect. However, the setting of the conventional windless zone and the ring-blowing cooling method are not applicable to the fiber developed this time, because the same spinneret of the fiber has two different shapes of spinnerets. In order to ensure the irregularity and cooling uniformity of the two shapes of the filament bundles, two different cooling effects are required, that is, the air volume on both sides of a circular blower is inconsistent, and the windless zones corresponding to the two bundles are inconsistent. The height of the windless zone is adjusted by adjusting the height of the two silicone sealing rings on the upper end of the blower (embedded between the blower fairing shell and the inner liner, which is the existing technology).

[0017] A method for preparing polyester drawn slubby yarn as described above, wherein one spinning position has 8 to 16 spinnerets, and the positions of the A area and the B area of ​​the spinneret on two adjacent spinnerets are opposite;

[0018] There is a wind tube corresponding to each spinneret assembly below, and the interior of the wind box where the wind tube is located is divided into multiple chambers, and each chamber is separated by a semi-circumferential surface of the wind tube and two vertical plates connected to two straight sides of the semi-circumferential surface, and 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 polyester drawn slubby yarn as described above, the number of holes of the spinneret is 144-288; the outer diameter of the spinneret is 95-105 mm, and the inner diameter is 80-90 mm.

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

[0022] In the method for preparing polyester drawn slubby yarn as described above, the cooling air pressure corresponding to area A on the spinneret is alternately changed between 35~42Pa and 65~70Pa, and the time interval for each alternating change is 0.25s, specifically, the air pressure is changed from 35~42Pa to 65~70Pa, and then changed back to 35~42Pa after an interval of 0.25s, and so on and so forth; the cooling air pressure corresponding to area B on the spinneret is alternately changed between 20~25Pa and 55~60Pa, and the time interval for each alternating change is 0.25s, specifically, the air pressure is changed from 20~25Pa to 55~60Pa, and then changed back to 20~25Pa after an interval of 0.25s, and so on and so forth.

[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 each other and a driving gear and a driven gear outside the air inlet duct using a designed driving method to achieve a reciprocating 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, the number of valve leaves is 3, 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 driving shaft is welded to each valve leaf, the axial direction of the driving shaft is parallel to the width direction of the valve leaf, both ends of the driving 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 arranged 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 driving shaft can rotate on the fixed bracket , so that the valve leaf rotates, thus realizing the opening and closing of the valve leaf, and the driving gears connected to each valve leaf mesh with each other; the lowest driving gear meshes 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, the driven gear and the driving gear are equal, all 5cm; the driving gear is driven by a motor and a reduction box, and when the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear meshes with the first transmission gear or the second transmission gear; such as Figure 4 As shown, when all the valve leaves are completely vertical, the air inlet valve is in a fully closed state; when all the valve leaves are completely horizontal, the air inlet valve is in a fully open state; 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 of the air inlet valve opening: first manually set an air valve opening, that is, a constant air inlet pressure and air valve clamping degree, for example, the valve leaf angle is 30°, and taking this as the starting point, when the active gear rotates counterclockwise, it first drives the first driven gear to rotate 30° clockwise. Because the driving gear is meshed 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 active gear continues to rotate and disengages the teeth of the first driven gear. After continuing to rotate, the active gear will mesh 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, and as the active gear keeps rotating, the valve leaf will regularly alternate between opening 30° and closing 30°.

[0025] The present invention also provides a polyester drawn slub yarn prepared by the preparation method as described above, wherein the specification of the polyester drawn slub yarn is 83-168dtex / 128-288f; the node length of the polyester drawn slub yarn is 10-12m, the breaking strength is greater than 3.8cN / 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 elongation at break and the boiling water shrinkage rate of continuous fibers alternately 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-node effect on the silk by alternating the cooling effect after spinning and spraying, and the bamboo-node effect is better, and the bamboo-node effect is 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 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 A schematic diagram of the distribution of spinneret holes on the spinneret of the present invention;

[0032] Figure 3 It is a schematic diagram of the distribution of the air cylinder and the chamber in the air box 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 is the wind direction;

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

[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] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it 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 within the scope limited by the appended claims of the application equally.

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

[0038] Breaking strength and elongation at break: The polyester drawn slub 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 GB / T 14344-2022 "Test method for tensile properties of chemical fiber filaments" standard; the specific process is: first, 20 1m polyester drawn slub yarns were continuously taken from a silk cake wound in each embodiment as samples, and then they were humidified for 4 hours at a temperature of 20°C and a humidity of 65%, and then the humidified samples were stretched until they broke using a fully automatic single yarn strength machine. When 20 samples were tested at the same time, 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 the clamping length to be 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 slubby yarns prepared in each embodiment were tested according to the skein method in GB / T 6505-2017 "Test method for thermal shrinkage of chemical fiber filaments (after treatment)"; the specific process is: first, 10 polyester drawn slubby yarns prepared in the same embodiment are taken out as samples, and then under the specified test conditions, the 10 samples are respectively treated with boiling water, and the changes in the lengths of the 10 samples before and after the treatment are measured and recorded, and the percentage of each sample to the original yarn length is calculated respectively, so as to obtain the boiling water shrinkage of each sample, and finally the average value is calculated, which is 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding; 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 positions of the A area and the B area of ​​the spinneret on two adjacent spinneret assemblies are opposite;

[0046] like Figure 1 As shown, the spinneret in the A region 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 holes in the B region are circular cross-section spinnerets with a diameter of 0.16 mm;

[0048] like Figure 3 As shown, there is a wind tube 10 corresponding to the lower side of each spinning assembly, and the interior of the wind box where the wind tube 10 is located is divided into 9 chambers, and each chamber is separated by a semi-circumferential surface of the wind tube 10 and two vertical plates 9 connected to two straight sides of the semi-circumferential surface, and 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, and air inlet valves are installed on the first air inlet duct 7 and the second air inlet duct 8 respectively.

[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 is composed 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. The height of each valve leaf 1 is 1 / 3 of the height of the air inlet. A driving shaft is welded to each valve leaf 1. The axial direction of the driving shaft is parallel to the width direction of the valve leaf 1. Both ends of the driving 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 the driving gear 2. The driving gear 2 connected to each valve leaf 1 is meshed with each other; the lowest driving gear 2 is meshed with the first driven gear 3, and is also connected to the second driven gear 4 through the 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 gear teeth on the gear with fewer teeth are arranged in the 1 / 12 area 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, and when the driving gear 6 rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear 6 meshes with the first transmission gear or the second transmission gear; as the driving gear 6 continues to rotate in the same direction, the position of the valve leaf 1 will change alternately, thereby realizing the alternating change of 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 cylinder 10 corresponding to area A on the spinneret is alternately changed between 35 Pa and 65 Pa, and the time interval of each alternation is 0.25 s;

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

[0053] The final polyester drawn bamboo yarn has a specification of 83dtex / 144f, a node length of 10m, a breaking strength of 4cN / dtex, a breaking elongation 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding. 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 12 spinnerets in total;

[0058] Each spinneret assembly has 18 rows of diamond-shaped spinneret holes on the spinneret plate, and any two adjacent rows of spinneret holes are staggered; the number of spinneret holes is 256; the outer diameter of the spinneret plate 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 positions of the A area and the B area of ​​the spinneret on two adjacent spinneret assemblies are opposite;

[0060] The spinneret in area A is a cross-section spinneret, 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;

[0061] The spinneret holes in the B region are circular cross-section spinnerets with a diameter of 0.16 mm;

[0062] There is a wind tube corresponding to each spinneret assembly below, and the interior of the wind box where the wind tube is located is divided into 13 chambers, and each chamber is separated by a semicircular surface of the wind tube and two vertical plates connected to two straight sides of the semicircular surface, and 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, and air inlet valves are installed on the first air inlet duct and the second air inlet duct respectively.

[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 a fixed bracket, and the other end is connected to a drive gear. The drive gears connected to each valve leaf are meshed with each other; the lowest drive gear is meshed 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 gear teeth on the gear with fewer teeth are arranged 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 box, and when the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear and the first transmission gear or the second transmission gear are meshed with each other; as the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby realizing the alternating change of 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, and the time interval of each alternation is 0.25 s;

[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, and the time interval of each alternation is 0.25 s.

[0067] The final polyester drawn bamboo yarn has a specification of 83dtex / 128f, a node length of 11m, a breaking strength of 3.95cN / dtex, a breaking elongation 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding; 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 16 spinnerets in total;

[0072] Each spinneret assembly has 20 rows of spinneret holes arranged in a diamond shape, and any two adjacent rows of spinneret holes are staggered; the number of spinneret holes is 288; 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 positions of the A area and the B area of ​​the spinneret on two adjacent spinneret assemblies are opposite;

[0074] The spinneret in area A is a cross-section spinneret, 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;

[0075] The spinneret holes in the B region are circular cross-section spinnerets with a diameter of 0.16 mm;

[0076] There is a wind tube corresponding to each spinneret assembly below, and the interior of the wind box where the wind tube is located is divided into 17 chambers, and each chamber is separated by a semi-circumferential surface of the wind tube and two vertical plates connected to two straight sides of the semi-circumferential surface, and 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;

[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, and air inlet valves are installed on the first air inlet duct and the second air inlet duct respectively.

[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 a fixed bracket, and the other end is connected to a drive gear. The drive gears connected to each valve leaf are meshed with each other; the lowest drive gear is meshed 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 gear teeth on the gear with fewer teeth are arranged 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 box, and when the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear and the first transmission gear or the second transmission gear are meshed with each other; as the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby realizing the alternating change of 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, and the time interval of each alternation is 0.25 s;

[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, and the time interval of each alternation is 0.25 s.

[0081] The final polyester drawn bamboo yarn has a specification of 168dtex / 288f, a node length of 12m, a breaking strength of 3.9cN / dtex, a breaking elongation 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding; 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 spinning position has a total of 10 spinnerets;

[0086] Each spinneret assembly has 16 rows of diamond-shaped spinneret holes on the spinneret plate, and any two adjacent rows of spinneret holes are staggered; the number of spinneret holes is 256; the outer diameter of the spinneret plate 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 positions of the A area and the B area of ​​the spinneret on two adjacent spinneret assemblies are opposite;

[0088] The spinneret in area A is a cross-section spinneret, 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;

[0089] The spinneret holes in the B region are circular cross-section spinnerets with a diameter of 0.16 mm;

[0090] There is a wind tube corresponding to each spinneret assembly below, and the interior of the wind box where the wind tube is located is divided into 11 chambers, and each chamber is separated by a semi-circumferential surface of the wind tube and two vertical plates connected to two straight sides of the semi-circumferential surface, and 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;

[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, and air inlet valves are installed on the first air inlet duct and the second air inlet duct respectively.

[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 a fixed bracket, and the other end is connected to a drive gear. The drive gears connected to each valve leaf are meshed with each other; the lowest drive gear is meshed 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 gear teeth on the gear with fewer teeth are arranged 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 box, and when the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear and the first transmission gear or the second transmission gear are meshed with each other; as the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby realizing the alternating change of 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, and the time interval of each alternation is 0.25 s;

[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, and the time interval of each alternation is 0.25 s.

[0095] The final polyester drawn bamboo yarn has a specification of 83dtex / 128f, a node length of 11m, a breaking strength of 3.95cN / dtex, a breaking elongation 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding. 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 12 spinnerets in total;

[0100] Each spinneret assembly has 18 rows of diamond-shaped spinneret holes on the spinneret plate, and any two adjacent rows of spinneret holes are staggered; the number of spinneret holes is 288; the outer diameter of the spinneret plate 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 positions of the A area and the B area of ​​the spinneret on two adjacent spinneret assemblies are opposite;

[0102] The spinneret in area A is a cross-section spinneret, 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;

[0103] The spinneret holes in the B region are circular cross-section spinnerets with a diameter of 0.16 mm;

[0104] There is a wind tube corresponding to each spinneret assembly below, and the interior of the wind box where the wind tube is located is divided into 13 chambers, and each chamber is separated by a semicircular surface of the wind tube and two vertical plates connected to two straight sides of the semicircular surface, and 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, and air inlet valves are installed on the first air inlet duct and the second air inlet duct respectively.

[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 a fixed bracket, and the other end is connected to a drive gear. The drive gears connected to each valve leaf are meshed with each other; the lowest drive gear is meshed 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 gear teeth on the gear with fewer teeth are arranged 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 box, and when the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear and the first transmission gear or the second transmission gear are meshed with each other; as the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby realizing the alternating change of 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, and the time interval of each alternation is 0.25 s;

[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, and the time interval of each alternation is 0.25 s.

[0109] The final polyester drawn bamboo yarn has a specification of 160dtex / 288f, a node length of 12m, a breaking strength of 3.9cN / dtex, a breaking elongation 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding. 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 12 spinnerets in total;

[0114] Each spinneret assembly has 18 rows of circular cross-section spinnerets arranged in a diamond shape, and any two adjacent rows of spinnerets are staggered; the number of spinneret holes is 288; the outer diameter of the spinneret is 105 mm, and the inner diameter is 90 mm; the diameter of the circular cross-section spinneret is 0.16 mm;

[0115] There is a wind tube corresponding to each spinning assembly below, 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. The number of valve leaves is 3, 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 driving shaft is welded on each valve leaf, and the axial direction of the driving shaft is parallel to the width direction of the valve leaf. Both ends of the driving shaft extend to the outside of the air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to a driving gear, which is meshed with the driving gear connected to each valve leaf; the lowest driving gear is connected to the first The driven gear is meshed and 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 gear teeth on the gear with fewer teeth are arranged 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 box. When the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear and the first transmission gear or the second transmission gear are meshed with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby realizing the alternating change of the cooling air volume in the air duct.

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

[0117] The final polyester drawn bamboo yarn has a specification of 160dtex / 288f, a node length of 10m, a breaking strength of 4.18cN / dtex, a breaking elongation 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 then cooled by alternating wind pressure. After cooling, the polyester drawn slub yarn was obtained by oiling and winding. 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 12 spinnerets in total;

[0122] Each spinneret assembly has 18 rows of cross-section spinneret holes arranged in a diamond shape, and any two adjacent rows of spinneret holes are staggered; the number of spinneret holes is 288; the outer diameter of the spinneret is 105 mm, and the inner diameter is 90 mm; the long lobe length of the cross-section spinneret hole 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;

[0123] There is a wind tube corresponding to each spinning assembly below, 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. The number of valve leaves is 3, 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 driving shaft is welded on each valve leaf, and the axial direction of the driving shaft is parallel to the width direction of the valve leaf. Both ends of the driving shaft extend to the outside of the air inlet duct, and one end is connected to the fixed bracket, and the other end is connected to a driving gear, which is meshed with the driving gear connected to each valve leaf; the lowest driving gear is connected to the first The driven gear is meshed and 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 gear teeth on the gear with fewer teeth are arranged 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 box. When the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear and the first transmission gear or the second transmission gear are meshed with each other. As the driving gear continues to rotate in the same direction, the position of the valve leaf will change alternately, thereby realizing the alternating change of the cooling air volume in the air duct.

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

[0125] The final polyester drawn bamboo yarn has a specification of 160dtex / 288f, a node length of 11m, a breaking strength of 3.73cN / dtex, a breaking elongation 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 a spinneret, it is cooled by alternating wind pressure, and after cooling, it is oiled and wound to obtain polyester drawn slub yarn.

2. The method for preparing polyester drawn slub yarn according to claim 1, characterized in that: The spinneret is provided with spinnerets arranged in multiple rows of rhombuses, 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.

3. The method for preparing polyester drawn slub yarn according to claim 2, characterized in that: 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.

4. The method for preparing polyester drawn slub yarn according to claim 3, characterized in that: 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; There is a wind tube corresponding to each spinneret assembly below, and the interior of the wind box where the wind tube is located is divided into multiple chambers, and each chamber is separated by a semi-circumferential surface of the wind tube and two vertical plates connected to two straight sides of the semi-circumferential surface, and 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, and air inlet valves are respectively installed on the first air inlet duct and the second air inlet duct.

5. The method for preparing polyester drawn slub yarn according to claim 4, characterized in that: The number of spinneret holes is 144~288; the outer diameter of the spinneret is 95~105mm, and the inner diameter is 80~90mm.

6. The method for preparing polyester drawn slub yarn according to claim 5, characterized in that: 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.

7. The method for preparing polyester drawn slub yarn according to claim 6, characterized in that: The cooling air pressure corresponding to area A on the spinneret changes alternately between 35~42Pa and 65~70Pa, and the time interval for each alternation is 0.25s; the cooling air pressure corresponding to area B on the spinneret changes alternately between 20~25Pa and 55~60Pa, and the time interval for each alternation is 0.25s.

8. The method for preparing polyester drawn slub yarn according to claim 7, characterized in that: The air inlet valve is composed of a valve body and a valve leaf inside 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 driving shaft is welded on each valve leaf. The axial direction of the driving shaft is parallel to the width direction of the valve leaf. Both ends of the driving 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, and the other end is connected to a driving gear. 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. 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 gear 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 box, and when the driving gear rotates until the gear teeth are close to the first transmission gear or the second transmission gear, the driving gear meshes with the first transmission gear or the second transmission gear; 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.

9. A polyester drawn slub yarn obtained by the preparation method according to claim 8, characterized in that: The specifications of polyester drawn slub yarn are 83~168dtex / 128~288f; the node length of polyester drawn slub yarn is 10~12m, the breaking strength is greater than 3.8cN / dtex, the breaking elongation is 35.0±3.0%, and the boiling water shrinkage is 15.0±1.0%.

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