Preparation method of polyester fabric with gradual dyeing effect

Abstract

The present application belongs to the technical field of textiles, and relates to a preparation method of a polyester fabric with a gradient dyeing effect, which comprises the following steps: after a fabric is woven from dynamic profiled yarns, the fabric is subjected to desizing and scouring treatment, and then is subjected to heat setting; subsequently, the heat-set fabric is immersed in a dye bath containing disperse dyes, and is subjected to dyeing by using a high-temperature and high-pressure dyeing method, so as to obtain a polyester fabric with a gradient dyeing effect; the cross-sectional shape of the monofilament of the dynamic profiled yarns periodically changes along the length direction, and the cross-sectional shape of the monofilament on each period is circular, flat and triangular in sequence. The present application realizes a differentiated dyeing effect, and simultaneously controls the timing of the nozzles, sets the cross-sectional change period, and makes the monofilament form a regular alternation of 'light-mid-dark' along the length direction, so that the finally prepared fabric presents a gradient dyeing effect after dyeing.

Description

Technical Field

[0001] This invention belongs to the field of textile technology and relates to a method for preparing polyester fabric with gradient dyeing effect. Background Technology

[0002] Shaped fibers, by altering their cross-sectional shape (such as triangular, trefoil, Y-shaped, hollow, etc.), overcome the limitations of traditional circular fibers in terms of performance, thereby enhancing physical properties and expanding functional applications to meet the needs of various fields. Because the cross-sectional shape of shaped fibers (such as triangular, trefoil, polygonal) can change the light reflection path, producing a special luster, they exhibit richer colors and sheens after dyeing. Therefore, existing technologies also utilize shaped fibers with different cross-sectional shapes to achieve gradient dyeing effects.

[0003] Gradient-dyed fabrics, with their unique color transition effects and artistic expression, have a wide and diverse range of applications in daily life, satisfying both practical functional needs and aesthetic and emotional value. However, existing methods for preparing fabrics with gradient dyeing effects typically suffer from problems such as complex processes, high pollution levels, and poor control flexibility, exhibiting significant technical limitations.

[0004] Patent CN107521230B discloses a digital inkjet printing method for sequential gradient printing. This method uses a sequential gradient printing digital inkjet printer to achieve sequential gradient printing on fabric placed on a flatbed. However, this method requires complex equipment to control the distance between the machine head and the flatbed, is cumbersome and causes significant pollution, and can only achieve color gradients on the fabric surface, failing to achieve seamless transitions between individual fibers.

[0005] The patent with authorization announcement number CN109666988B discloses a method for preparing bamboo-joint fibers. This method forms a "coarse-fine" structure by extruding through a DTY stage groove-breaking roller. However, it relies on a fixed groove size and cycle, which can only produce discrete stripe-like dyeing differences and cannot achieve a continuous and uniform transition of shape. Furthermore, secondary processing depletes fiber properties.

[0006] Therefore, a method for preparing polyester fabrics with gradient dyeing effect is needed to solve the above problems, which is of great significance. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and provide a method for preparing polyester fabrics with gradient dyeing effect.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing polyester fabric with gradient dyeing effect involves first desizing and scouring the fabric after it is woven from dynamic profiled yarns to remove weaving oil and sizing impurities, then heat setting the fabric, and finally immersing the heat-set fabric in a dye bath containing disperse dyes and dyeing it using a high-temperature and high-pressure dyeing method. By utilizing the density difference of different regions of the asymmetric cross section of the dynamic profiled yarns, the amount of disperse dye adsorbed in different regions of the yarns is different, thus forming dyeing differences and obtaining polyester fabric with gradient dyeing effect.

[0010] The cross-sectional shape of the single filament of the dynamic profiled filament changes periodically along its length, with the cross-sectional shape of the single filament in each cycle being circular, flat, and triangular, respectively.

[0011] As a preferred technical solution:

[0012] In the method for preparing a polyester fabric with a gradient dyeing effect as described above, the ratio of the lengths of the circular cross-section, the flat cross-section, and the triangular cross-section in each cycle along the length direction of the dynamic profiled filament is 1:0.2~10:0.1~5.

[0013] As described above, in the method for preparing a polyester fabric with gradient dyeing effect, the color difference between areas with different cross-sectional shapes of the dynamic profiled yarn is ≥2 levels, and the color difference between adjacent areas with different dyeing effects on the polyester fabric with gradient dyeing effect is ≥1.5 levels.

[0014] The preparation method of a polyester fabric with gradient dyeing effect as described above, the preparation method of dynamic profiled yarn is as follows: the polyester melt sprayed from the spinneret is first initially cooled to 200~240℃ in the spinning tunnel to obtain a pre-formed monofilament. Then, cold air at 0~20℃ is periodically applied to the pre-formed monofilament in the spinning tunnel to reduce the temperature of the impacted area to 70~80℃ within 10~50ms. After that, the monofilament coming out of the spinning tunnel is sequentially bundled, stretched and shaped, oiled and wound to obtain dynamic profiled yarn.

[0015] The application of cold air impact is achieved through a single-filament cold air dynamic irregular nozzle system installed in the spinning tunnel. The entire single-filament cold air dynamic irregular nozzle system is installed in the spinning tunnel by a bracket.

[0016] The monofilament cold air dynamic irregular nozzle system includes a nozzle module and a control system. The control system controls the position, time, and interval of nozzle opening / closing according to a preset program. The control system includes a solenoid valve, a nozzle switch controller, and a cold air pressure regulating valve. The nozzle module is composed of multiple nozzles, each of which applies cold air to a monofilament. Each nozzle has multiple annularly distributed air outlets facing the circumference of the monofilament. A solenoid valve is installed on the pipe corresponding to each air outlet. All solenoid valves are connected to the nozzle switch controller via cables, and the nozzle switch controller controls the opening and closing of the solenoid valves. All nozzles are connected to a main air inlet pipe via air pipes. A cold air pressure regulating valve is installed at the inlet of the main air inlet pipe to regulate the nozzle outlet air temperature and pressure.

[0017] Each nozzle has 6 air outlets. The cold air impact is applied periodically. This means that two air outlets are opened to simultaneously impact the monofilament with cold air from opposite sides for 20-50ms. Then, the nozzles are switched to three air outlets evenly arranged around the circumference to simultaneously impact the monofilament with cold air for 10-25ms. The cold air impact process is repeated after an interval of 5-100ms. (The interval time can be adjusted according to production needs, but if the interval time exceeds 100ms, it will cause a long blank segment, and the gradation effect will not be obvious after weaving and dyeing.)

[0018] The method for preparing a polyester fabric with gradient dyeing effect as described above involves a spinneret orifice diameter of 0.1~0.3mm, a polyester melt temperature of 280~300℃, and a spinneret speed of 10~18m / min.

[0019] In the method for preparing a polyester fabric with a gradient dyeing effect as described above, the diameter of the air outlet hole on each nozzle is 0.05~0.2mm, and the diameter of the inlet hole of the nozzle for monofilament to pass through is 0.2~0.6mm.

[0020] The method for preparing a polyester fabric with a gradient dyeing effect as described above uses ring-blowing cooling or side-blowing cooling for initial cooling, with a cooling air temperature of 20~30℃ and a cooling air velocity of 0.8~1.5m / s.

[0021] In the method for preparing a polyester fabric with a gradient dyeing effect as described above, the height of the nozzle module from the annular or side-blowing area is 30-80 cm.

[0022] The method for preparing a polyester fabric with a gradient dyeing effect as described above uses a heat setting temperature of 180~220℃.

[0023] The preparation method of polyester fabric with gradient dyeing effect as described above, the process parameters of high temperature and high pressure dyeing are: dye bath pressure 0.15~0.3MPa, liquor ratio 1:8~1:20, mass fraction of disperse dye 2~5%, amount of disperse dye auxiliary agent (such as dispersant) 0.5%~1.5% (owf), and fabric running frequency of 3~5r / min is applied simultaneously during the heat preservation stage of 120~130℃.

[0024] After dyeing, the fabric is washed with cold water and then with warm water to remove excess dye. It is then subjected to reduction cleaning (using a mixed aqueous solution of 0.5%~1% sodium hydrosulfite and 1%~2% sodium hydroxide, treated at 70~85℃ for 10~30min). Finally, after drying, a polyester fabric with a gradient dyeing effect is obtained. The cold water temperature is 15~25℃, the warm water temperature is 40~50℃, the drying temperature is 80~120℃, and the drying time is 15~40min.

[0025] Invention principle:

[0026] To address the problems of complex preparation processes, high pollution, and poor control flexibility in existing technologies for achieving gradient dyeing effects, this invention creatively proposes a new method for realizing gradient dyeing effects. This invention achieves differentiated dyeing effects by designing a dynamic profiled filament and utilizing the periodically changing cross-section of the filament (circular → flat → triangular). The cross-sectional shape of the monofilament directly affects the amount of dye adsorbed, thus determining the color depth: For the same filament with a constant unit length mass (density), a circular cross-section has a small surface area and uniform curvature, resulting in less dye adsorption and a lighter color. A flat cross-section has a larger surface area than a circular cross-section (among all closed shapes, the circle has the smallest "perimeter / area ratio"—meaning a circle uses the smallest perimeter to enclose the largest cross-sectional area, while a flat cross-section deviates from the circular structure, significantly increasing its perimeter. As the perimeter increases, the fiber surface area also increases, because surface area ≈ perimeter × length, so as the perimeter increases, the surface area increases accordingly), resulting in a medium adsorption and a medium color. A triangular cross-section, due to its large curvature at the corners, produces a dye aggregation effect, thus adsorbing the most dye compared to circular and flat cross-sections, resulting in a darker color. By controlling the nozzle timing and setting the cross-sectional change cycle, the monofilaments alternate in a "light-medium-dark" pattern along their length, ultimately creating a gradient dyeing effect on the fabric.

[0027] Beneficial effects:

[0028] This invention utilizes the periodically changing cross-section of dynamic profiled yarns to achieve differentiated dyeing effects. Simultaneously, by controlling the nozzle timing and setting the cross-section change period, the monofilaments form a regular alternation of "light-medium-dark" along the length direction. The resulting fabric exhibits a gradient dyeing effect after dyeing, avoiding the problems of complex preparation processes, high pollution, and poor control flexibility in existing technologies. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0031] Dyeing uniformity: The dyed dynamic profiled yarns were disassembled from the polyester fabrics with gradient dyeing effect prepared in each embodiment as samples, and the dyeing uniformity of a single sample was tested in accordance with GB / T 6508-2001 "Test Method for Dyeing Uniformity of Polyester Filament".

[0032] Color difference in regions with different cross-sectional shapes of dynamic profiled yarns on polyester fabrics with gradient dyeing effect: The dyed dynamic profiled yarns were disassembled from the polyester fabrics with gradient dyeing effect prepared in each embodiment as samples. Then, the color values ​​of yarn segments with different cross-sectional shapes on the samples were tested using a colorimeter. The color grade of each profiled segment was evaluated with reference to the GB / T 250-2008 standard "Textiles - Tests for Color Fastness - Assessment of Color Change - Gray Scale". Finally, the maximum color difference grade was calculated.

[0033] Color difference between adjacent areas with different dyeing effects on polyester fabrics with gradient dyeing effect: The polyester fabrics with gradient dyeing effect prepared in each embodiment were used as samples. Then, on the samples, dark-medium and medium-light color areas were divided according to the surface gradient transition. Five test points were selected in each area and the average color value of each area was measured by a colorimeter for comparison. Finally, the color difference level was evaluated with reference to GB / T 4841.3-2006 "Standard Depth Color Card for Dyeing".

[0034] Example 1

[0035] A method for preparing a polyester fabric with a gradient dyeing effect, comprising the following steps:

[0036] (1) Preparation of raw materials;

[0037] Polyester chips: Semi-dull polyester chips, manufactured by Jiangsu Hengke New Materials Co., Ltd., batch number MS01;

[0038] Auxiliary yarn: Polyester filament, manufactured by Jiangsu Hengke New Material Co., Ltd., specification 150D / 96F semi-dull DTY;

[0039] Amylase aqueous solution: 5% amylase aqueous solution;

[0040] A mixed aqueous solution of sodium hydroxide and surfactant: composed of sodium hydroxide, surfactant (fatty alcohol polyoxyethylene ether AEO-9) and water, wherein the mass fraction of sodium hydroxide is 6% and the mass fraction of surfactant is 4%.

[0041] Dye bath containing disperse dye: composed of dye (Disperse Blue 2BLN), disperse dye auxiliary agent (dispersant NNO) and water, the pH value of the dye bath is 6, the mass fraction of disperse dye in the dye bath is 5%, and the amount of disperse dye auxiliary agent is 1.5% (owf).

[0042] A mixed solution of sodium hydrosulfite and sodium hydroxide: composed of 1% sodium hydrosulfite by mass, 2% sodium hydroxide by mass, and water;

[0043] (2) After the polyester chips are melted, the polyester melt is sprayed out through the spinneret. Then, the polyester melt is initially cooled to 240°C in the spinning tunnel by ring blowing to obtain the preliminarily formed monofilament. The spinneret hole diameter is 0.3 mm, the temperature of the polyester melt is 300°C, the spinning speed is 18 m / min, the cooling air temperature is 30°C, and the cooling air velocity is 1.5 m / s.

[0044] (3) In the spinning tunnel, the initially formed monofilament is periodically subjected to 0°C cold air impact by a monofilament cold air dynamic irregular nozzle system installed in the spinning tunnel, so that the temperature of the impacted area drops to 80°C; wherein, the cold air impact pressure is 0.5MPa, and the monofilament cold air dynamic irregular nozzle system includes a nozzle module and a control system.

[0045] The control system includes solenoid valves, nozzle switch controllers, and cold air pressure regulating valves;

[0046] The nozzle module consists of three nozzles. Each nozzle is used to apply cold air to a single filament. Each nozzle has multiple evenly distributed annular air outlets facing the circumference of the single filament. A solenoid valve is installed on the pipe corresponding to each air outlet. All solenoid valves are connected to the nozzle switch controller via cables. All nozzles are connected to the main air inlet pipe via air pipes. A cold air pressure regulating valve is installed at the inlet of the main air inlet pipe.

[0047] Each nozzle has 6 air outlets. The periodic application of cold air impact means that two air outlets are opened to simultaneously impact the monofilament with cold air from opposite sides for 20ms, and then the three air outlets are evenly arranged along the circumference to simultaneously impact the monofilament with cold air for 10ms. The cold air impact process is repeated after an interval of 100ms.

[0048] The nozzle module is 30cm above the ring blowing area. Each nozzle has 3 air outlets with a diameter of 0.2mm. The nozzle for monofilament passage has an inlet diameter of 0.6mm.

[0049] (4) The monofilaments coming out of the spinning tunnel are successively bundled, stretched and shaped, oiled and wound to produce dynamic profiled yarns; wherein the draw ratio is 50 times;

[0050] The cross-sectional shape of the obtained dynamic profiled filament changes periodically along its length. The cross-sectional shape of the filament in each cycle is circular, flat, and triangular, respectively, and the length ratio of the corresponding circular, flat, and triangular cross-sections is 1:0.2:0.1.

[0051] (5) Fabric weaving and pretreatment;

[0052] (5.1) The dynamic profiled yarns obtained above and the auxiliary yarns are woven into a greige fabric on a loom with a plain weave structure;

[0053] (5.2) The woven fabric is desized at 55°C for 25 minutes using an amylase aqueous solution, and then refined at 100°C for 40 minutes using a mixed aqueous solution of sodium hydroxide and surfactant. This removes impurities and improves dyeing performance. Finally, it is heat-set at 220°C.

[0054] (6) The heat-set fabric is immersed in a dye bath containing disperse dyes and dyed using a high-temperature and high-pressure dyeing method; wherein the dye bath pressure is 0.3 MPa, the bath ratio is 1:20, and a fabric running frequency of 4 r / min is applied simultaneously during the 130℃ heat preservation stage.

[0055] (7) After dyeing, wash with cold water at 25°C for 12 minutes, then wash with warm water at 50°C for 12 minutes to remove floating color. Then use a mixed solution of sodium hydrosulfite and sodium hydroxide to reduce and clean at 85°C for 30 minutes. Finally, dry at 120°C for 40 minutes to obtain polyester fabric with gradient dyeing effect.

[0056] The final polyester fabric with gradient dyeing effect has a color difference level of 4 in the areas with different cross-sectional shapes of the dynamic profiled yarn monofilaments, and a color difference level of 3 in adjacent areas with different dyeing effects on the polyester fabric with gradient dyeing effect.

[0057] The dyeing uniformity of the dynamic profiled yarns in the polyester fabric with gradient dyeing effect is grade 5.

[0058] Example 2

[0059] A method for preparing a polyester fabric with a gradient dyeing effect, comprising the following steps:

[0060] (1) Preparation of raw materials;

[0061] Polyester chips: Semi-dull polyester chips, manufactured by Jiangsu Hengke New Materials Co., Ltd., batch number MS01;

[0062] Auxiliary yarn: Polyester filament, manufactured by Jiangsu Hengke New Material Co., Ltd., specification 120D / 96F semi-dull DTY;

[0063] Amylase aqueous solution: 4% amylase aqueous solution;

[0064] A mixed aqueous solution of sodium hydroxide and surfactant: composed of sodium hydroxide, surfactant (fatty alcohol polyoxyethylene ether AEO-9) and water, wherein the mass fraction of sodium hydroxide is 5% and the mass fraction of surfactant is 3.5%;

[0065] Dye bath containing disperse dye: composed of dye (Disperse Blue 2BLN), disperse dye auxiliary agent (dispersant NNO) and water, the pH value of the dye bath is 5.5, the mass fraction of disperse dye in the dye bath is 4.5%, and the amount of disperse dye auxiliary agent is 1.2% (owf).

[0066] A mixed solution of sodium hydrosulfite and sodium hydroxide: composed of 0.9% sodium hydrosulfite, 1.8% sodium hydroxide, and water;

[0067] (2) After the polyester chips are melted, the polyester melt is sprayed out through the spinneret. Then, the polyester melt is initially cooled to 220°C in the spinning tunnel by side blowing to obtain the preliminarily formed monofilament. The spinneret hole diameter is 0.2 mm, the temperature of the polyester melt is 290°C, the spinning speed is 12 m / min, the cooling air temperature is 27°C, and the cooling air velocity is 1.3 m / s.

[0068] (3) In the spinning tunnel, the initially formed monofilament is periodically subjected to cold air impact at 10°C through the monofilament cold air dynamic irregular nozzle system installed in the spinning tunnel, so that the temperature of the impacted area drops to 75°C; wherein, the cold air impact pressure is 0.4MPa, and the monofilament cold air dynamic irregular nozzle system includes nozzle module and control system.

[0069] The control system includes solenoid valves, nozzle switch controllers, and cold air pressure regulating valves;

[0070] The nozzle module consists of 9 nozzles. Each nozzle is used to apply cold air to a single filament. Each nozzle has multiple evenly distributed annular air outlets facing the circumference of the single filament. A solenoid valve is installed on the pipe corresponding to each air outlet. All solenoid valves are connected to the nozzle switch controller via cables. All nozzles are connected to the main air inlet pipe via air pipes. A cold air pressure regulating valve is installed at the inlet of the main air inlet pipe.

[0071] Each nozzle has 6 air outlets. The periodic application of cold air impact means that two air outlets are opened to simultaneously impact the monofilament with cold air from opposite sides for 40ms, and then the three air outlets are switched to be evenly arranged around the circumference to simultaneously impact the monofilament with cold air for 20ms. The cold air impact process is repeated after an interval of 80ms.

[0072] The nozzle module is 50cm above the side blowing area. Each nozzle has 9 air outlets with a diameter of 0.2mm. The nozzle for monofilament passage has an inlet diameter of 0.3mm.

[0073] (4) The monofilaments coming out of the spinning tunnel are successively bundled, stretched and shaped, oiled and wound to produce dynamic profiled yarns; wherein the draw ratio is 40 times;

[0074] The cross-sectional shape of the obtained dynamic profiled filament changes periodically along its length. The cross-sectional shape of the filament in each cycle is circular, flat, and triangular, respectively, and the length ratio of the corresponding circular, flat, and triangular cross-sections is 1:0.5:0.25.

[0075] (5) Fabric weaving and pretreatment;

[0076] (5.1) The dynamic profiled yarns obtained above and the auxiliary yarns are woven into a greige fabric on a loom with a plain weave structure;

[0077] (5.2) The woven fabric is desized at 56°C for 26 min using an amylase aqueous solution, and then refined at 98°C for 38 min using a mixed aqueous solution of sodium hydroxide and surfactant. This removes impurities and improves dyeing performance. Finally, it is heat-set at 210°C.

[0078] (6) The heat-set fabric is immersed in a dye bath containing disperse dye and dyed using a high-temperature and high-pressure dyeing method; wherein the dye bath pressure is 0.25 MPa, the bath ratio is 1:15, and a fabric running frequency of 4 r / min is applied simultaneously during the 130℃ heat preservation stage.

[0079] (7) After dyeing, wash with cold water at 22°C for 13 minutes, then wash with warm water at 48°C for 13 minutes to remove floating color. Then use a mixed solution of sodium hydrosulfite and sodium hydroxide at 80°C for 25 minutes to reduce and clean. Finally, dry at 100°C for 30 minutes to obtain polyester fabric with gradient dyeing effect.

[0080] The final polyester fabric with gradient dyeing effect has a color difference grade of 3.5 in areas with different cross-sectional shapes of dynamic profiled yarn monofilaments, and a color difference grade of 2.5 in adjacent areas with different dyeing effects on the polyester fabric with gradient dyeing effect.

[0081] The dyeing uniformity of the dynamic profiled yarns in the polyester fabric with gradient dyeing effect is grade 4.5.

[0082] Example 3

[0083] A method for preparing a polyester fabric with a gradient dyeing effect, comprising the following steps:

[0084] (1) Preparation of raw materials;

[0085] Polyester chips: Semi-dull polyester chips, manufactured by Jiangsu Hengke New Materials Co., Ltd., batch number MS01;

[0086] Auxiliary yarn: Polyester filament, manufactured by Jiangsu Hengke New Material Co., Ltd., specification 100D / 96F semi-dull DTY;

[0087] Amylase aqueous solution: 3.5% amylase aqueous solution;

[0088] A mixed aqueous solution of sodium hydroxide and surfactant: composed of sodium hydroxide, surfactant (fatty alcohol polyoxyethylene ether AEO-9) and water, wherein the mass fraction of sodium hydroxide is 4.5% and the mass fraction of surfactant is 3%.

[0089] Dye bath containing disperse dye: composed of dye (Disperse Blue 2BLN), disperse dye auxiliary agent (dispersant NNO) and water, the pH value of the dye bath is 5.3, the mass fraction of disperse dye in the dye bath is 4%, and the amount of disperse dye auxiliary agent is 1% (owf).

[0090] A mixed solution of sodium hydrosulfite and sodium hydroxide: composed of 0.8% sodium hydrosulfite, 1.5% sodium hydroxide, and water;

[0091] (2) After the polyester chips are melted, the polyester melt is sprayed out through the spinneret. Then, the polyester melt is initially cooled to 210°C in the spinning tunnel by ring blowing to obtain the preliminarily formed monofilament. The spinneret hole diameter is 0.1 mm, the temperature of the polyester melt is 285°C, the spinning speed is 15 m / min, the cooling air temperature is 25°C, and the cooling air velocity is 1.1 m / s.

[0092] (3) In the spinning tunnel, the initially formed monofilament is periodically subjected to cold air impact at 20°C through the monofilament cold air dynamic irregular nozzle system installed in the spinning tunnel, so that the temperature of the impacted area drops to 80°C; wherein, the cold air impact pressure is 0.3MPa, and the monofilament cold air dynamic irregular nozzle system includes nozzle module and control system.

[0093] The control system includes solenoid valves, nozzle switch controllers, and cold air pressure regulating valves;

[0094] The nozzle module consists of 12 nozzles. Each nozzle is used to apply cold air to a single filament. Each nozzle has multiple evenly distributed annular air outlets facing the circumference of the single filament. A solenoid valve is installed on the pipe corresponding to each air outlet. All solenoid valves are connected to the nozzle switch controller via cables. All nozzles are connected to the main air inlet pipe via air pipes. A cold air pressure regulating valve is installed at the inlet of the main air inlet pipe.

[0095] Each nozzle has 6 air outlets. The periodic application of cold air impact means that two air outlets are opened to simultaneously impact the monofilament with cold air from opposite sides for 45ms, and then the three air outlets are switched to be evenly arranged around the circumference to simultaneously impact the monofilament with cold air for 15ms. The cold air impact process is repeated after a 15ms interval.

[0096] The nozzle module is 70cm above the ring blowing area. Each nozzle has 12 air outlets with a diameter of 0.1mm. The nozzle for monofilament passage has an inlet diameter of 0.2mm.

[0097] (4) The monofilaments coming out of the spinning tunnel are successively bundled, stretched and shaped, oiled and wound to produce dynamic profiled yarns; wherein the draw ratio is 30 times;

[0098] The cross-sectional shape of the obtained dynamic profiled filament changes periodically along the length direction. The cross-sectional shape of the filament in each cycle is circular, flat, and triangular, respectively, and the length ratio of the corresponding circular, flat, and triangular cross-sections is 1:3:1.

[0099] (5) Fabric weaving and pretreatment;

[0100] (5.1) The dynamic profiled yarns obtained above are woven with auxiliary yarns on a loom in a twill weave structure to form a grey fabric;

[0101] (5.2) The woven fabric is desized at 57°C for 27 min using an amylase aqueous solution, and then refined at 95°C for 35 min using a mixed aqueous solution of sodium hydroxide and surfactant. This removes impurities and improves dyeing performance. Finally, it is heat-set at 200°C.

[0102] (6) The heat-set fabric is immersed in a dye bath containing disperse dyes and dyed using a high-temperature and high-pressure dyeing method; wherein the dye bath pressure is 0.2 MPa, the bath ratio is 1:12, and a fabric running frequency of 4 r / min is applied simultaneously during the 125℃ heat preservation stage.

[0103] (7) After dyeing, wash with cold water at 20°C for 13 minutes, then wash with warm water at 45°C for 13 minutes to remove floating color. Then use a mixed solution of sodium hydrosulfite and sodium hydroxide to reduce and clean at 75°C for 20 minutes. Finally, dry at 90°C for 25 minutes to obtain polyester fabric with gradient dyeing effect.

[0104] The final polyester fabric with gradient dyeing effect has a color difference level of 3 in the areas with different cross-sectional shapes of the dynamic profiled yarn monofilaments, and a color difference level of 2 in adjacent areas with different dyeing effects on the polyester fabric with gradient dyeing effect.

[0105] The dyeing uniformity of the dynamic profiled yarns in the polyester fabric with gradient dyeing effect is grade 4.5.

[0106] Example 4

[0107] A method for preparing a polyester fabric with a gradient dyeing effect, comprising the following steps:

[0108] (1) Preparation of raw materials;

[0109] Polyester chips: Semi-dull polyester chips, manufactured by Jiangsu Hengke New Materials Co., Ltd., batch number MS01;

[0110] Auxiliary yarn: Polyester filament, manufactured by Jiangsu Hengke New Material Co., Ltd., specification 100D / 96F semi-dull DTY;

[0111] Amylase aqueous solution: 3% amylase aqueous solution;

[0112] A mixed aqueous solution of sodium hydroxide and surfactant: composed of sodium hydroxide, surfactant (fatty alcohol polyoxyethylene ether AEO-9) and water, wherein the mass fraction of sodium hydroxide is 4% and the mass fraction of surfactant is 2.5%;

[0113] Dye bath containing disperse dye: composed of dye (Disperse Blue 2BLN), disperse dye auxiliary agent (dispersant NNO) and water, the pH value of the dye bath is 5.1, the mass fraction of disperse dye in the dye bath is 3%, and the amount of disperse dye auxiliary agent is 0.8% (owf).

[0114] A mixed solution of sodium hydrosulfite and sodium hydroxide: composed of 0.7% sodium hydrosulfite, 1.2% sodium hydroxide, and water;

[0115] (2) After the polyester chips are melted, the polyester melt is sprayed out through the spinneret. Then, the polyester melt is initially cooled to 200°C in the spinning tunnel by ring blowing to obtain the preliminarily formed monofilament. The spinneret hole diameter is 0.1 mm, the temperature of the polyester melt is 280°C, the spinning speed is 10 m / min, the cooling air temperature is 20°C, and the cooling air velocity is 0.8 m / s.

[0116] (3) In the spinning tunnel, the initially formed monofilament is periodically subjected to cold air impact at 20°C through the monofilament cold air dynamic irregular nozzle system installed in the spinning tunnel, so that the temperature of the impacted area drops to 70°C; wherein, the cold air impact pressure is 0.2MPa, and the monofilament cold air dynamic irregular nozzle system includes nozzle module and control system.

[0117] The control system includes solenoid valves, nozzle switch controllers, and cold air pressure regulating valves;

[0118] The nozzle module consists of 36 nozzles. Each nozzle is used to apply cold air to a single filament. Each nozzle has multiple evenly distributed annular air outlets facing the circumference of the single filament. A solenoid valve is installed on the pipe corresponding to each air outlet. All solenoid valves are connected to the nozzle switch controller via cables. All nozzles are connected to the main air inlet pipe via air pipes. A cold air pressure regulating valve is installed at the inlet of the main air inlet pipe.

[0119] Each nozzle has 6 air outlets. The periodic application of cold air impact means that two air outlets are opened to simultaneously impact the monofilament with cold air from opposite sides for 35ms, and then the three air outlets are evenly arranged along the circumference to simultaneously impact the monofilament with cold air for 15ms. The cold air impact process is repeated after a 5ms interval.

[0120] The nozzle module is 80cm above the ring blowing area. Each nozzle has 36 air outlets with a diameter of 0.05mm. The nozzle for monofilament passage has an inlet diameter of 0.2mm.

[0121] (4) The monofilaments coming out of the spinning tunnel are successively bundled, stretched and shaped, oiled and wound to produce dynamic profiled yarns; wherein the draw ratio is 20 times;

[0122] The cross-sectional shape of the obtained dynamic profiled filament changes periodically along the length direction. The cross-sectional shape of the filament in each cycle is circular, flat, and triangular, respectively, and the length ratio of the corresponding circular, flat, and triangular cross-sections is 1:7:3.

[0123] (5) Fabric weaving and pretreatment;

[0124] (5.1) The dynamic profiled yarns obtained above are woven with auxiliary yarns on a loom in a twill weave structure to form a grey fabric;

[0125] (5.2) The woven fabric is desized at 58°C for 28 minutes using an amylase aqueous solution, and then refined at 92°C for 32 minutes using a mixed aqueous solution of sodium hydroxide and surfactant. This removes impurities and improves dyeing performance. Finally, it is heat-set at 190°C.

[0126] (6) The heat-set fabric is immersed in a dye bath containing disperse dyes and dyed using a high-temperature and high-pressure dyeing method; wherein the dye bath pressure is 0.15MPa, the bath ratio is 1:10, and a fabric running frequency of 4r / min is applied simultaneously during the 120℃ heat preservation stage.

[0127] (7) After dyeing, wash with cold water at 18°C ​​for 14 minutes, then wash with warm water at 42°C for 14 minutes to remove floating color. Then use a mixed solution of sodium hydrosulfite and sodium hydroxide to reduce and clean at 70°C for 15 minutes. Finally, dry at 85°C for 20 minutes to obtain polyester fabric with gradient dyeing effect.

[0128] The final polyester fabric with gradient dyeing effect has a color difference grade of 2.5 in areas with different cross-sectional shapes of dynamic profiled yarn monofilaments, and a color difference grade of 1.8 in adjacent areas with different dyeing effects on the polyester fabric with gradient dyeing effect.

[0129] The dyeing uniformity of the dynamic profiled yarns in the polyester fabric with gradient dyeing effect is grade 4.

[0130] Example 5

[0131] A method for preparing a polyester fabric with a gradient dyeing effect, comprising the following steps:

[0132] (1) Preparation of raw materials;

[0133] Polyester chips: Semi-dull polyester chips, manufactured by Jiangsu Hengke New Materials Co., Ltd., batch number MS01;

[0134] Auxiliary yarn: Polyester filament, manufactured by Jiangsu Hengke New Material Co., Ltd., specification 100D / 96F semi-dull DTY;

[0135] Amylase aqueous solution: 2% amylase aqueous solution;

[0136] A mixed aqueous solution of sodium hydroxide and surfactant: composed of sodium hydroxide, surfactant (fatty alcohol polyoxyethylene ether AEO-9) and water, wherein the mass fraction of sodium hydroxide is 3% and the mass fraction of surfactant is 2%.

[0137] Dye bath containing disperse dye: composed of dye (Disperse Blue 2BLN), disperse dye auxiliary agent (dispersant NNO) and water, the pH value of the dye bath is 5, the mass fraction of disperse dye in the dye bath is 2%, and the amount of disperse dye auxiliary agent is 0.5% (owf).

[0138] A mixed solution of sodium hydrosulfite and sodium hydroxide: composed of 0.5% sodium hydrosulfite, 1% sodium hydroxide, and water;

[0139] (2) After the polyester chips are melted, the polyester melt is sprayed out through the spinneret. Then, the polyester melt is initially cooled to 200°C in the spinning tunnel by ring blowing to obtain the preliminarily formed monofilament. The spinneret hole diameter is 0.1 mm, the temperature of the polyester melt is 280°C, the spinning speed is 10 m / min, the cooling air temperature is 20°C, and the cooling air velocity is 0.8 m / s.

[0140] (3) In the spinning tunnel, the initially formed monofilament is periodically subjected to cold air impact at 20°C through the monofilament cold air dynamic irregular nozzle system installed in the spinning tunnel, so that the temperature of the impacted area drops to 70°C; wherein, the cold air impact pressure is 0.2MPa, and the monofilament cold air dynamic irregular nozzle system includes nozzle module and control system.

[0141] The control system includes solenoid valves, nozzle switch controllers, and cold air pressure regulating valves;

[0142] The nozzle module consists of 36 nozzles. Each nozzle is used to apply cold air to a single filament. Each nozzle has multiple evenly distributed annular air outlets facing the circumference of the single filament. A solenoid valve is installed on the pipe corresponding to each air outlet. All solenoid valves are connected to the nozzle switch controller via cables. All nozzles are connected to the main air inlet pipe via air pipes. A cold air pressure regulating valve is installed at the inlet of the main air inlet pipe.

[0143] Each nozzle has 6 air outlets. The periodic application of cold air impact means that two air outlets are opened to simultaneously impact the monofilament with cold air from opposite sides for 50ms, and then the three air outlets are evenly arranged along the circumference to simultaneously impact the monofilament with cold air for 25ms. The cold air impact process is repeated after a 5ms interval.

[0144] The nozzle module is 80cm above the ring blowing area. Each nozzle has 36 air outlets with a diameter of 0.05mm. The nozzle for monofilament passage has an inlet diameter of 0.2mm.

[0145] (4) The monofilaments coming out of the spinning tunnel are successively bundled, stretched and shaped, oiled and wound to produce dynamic profiled yarns; wherein the draw ratio is 20 times;

[0146] The cross-sectional shape of the obtained dynamic profiled filament changes periodically along the length direction. The cross-sectional shape of the filament in each cycle is circular, flat, and triangular, respectively, and the length ratio of the corresponding circular, flat, and triangular cross-sections is 1:10:5.

[0147] (5) Fabric weaving and pretreatment;

[0148] (5.1) The dynamic profiled yarns obtained above are woven with auxiliary yarns on a loom in a twill weave structure to form a grey fabric;

[0149] (5.2) The woven fabric is desized at 60°C for 30 minutes using an amylase aqueous solution, and then refined at 90°C for 30 minutes using a mixed aqueous solution of sodium hydroxide and surfactant. This removes impurities and improves dyeing performance. Finally, it is heat-set at 180°C.

[0150] (6) The heat-set fabric is immersed in a dye bath containing disperse dye and dyed using a high-temperature and high-pressure dyeing method; wherein the dye bath pressure is 0.15MPa, the bath ratio is 1:8, and a fabric running frequency of 4r / min is applied simultaneously during the 120℃ heat preservation stage.

[0151] (7) After dyeing, wash with cold water at 15°C for 15 minutes, then wash with warm water at 40°C for 15 minutes to remove floating color. Then use a mixed solution of sodium hydrosulfite and sodium hydroxide to reduce and clean at 70°C for 10 minutes. Finally, dry at 80°C for 15 minutes to obtain polyester fabric with gradient dyeing effect.

[0152] The final polyester fabric with gradient dyeing effect has a color difference grade of 2 in the areas with different cross-sectional shapes of the dynamic profiled yarn monofilaments, and a color difference grade of 1.5 in adjacent areas with different dyeing effects on the polyester fabric with gradient dyeing effect.

[0153] The dyeing uniformity of the dynamic profiled yarns in the polyester fabric with gradient dyeing effect is grade 4.

Claims

1. A process for the preparation of polyester fabric with gradual dyeing effect, characterized by: After the fabric is woven from the dynamic profiled yarn, the fabric is subjected to desizing and scouring treatment, and then is subjected to heat setting, and then the heat set fabric is immersed in a dye bath containing disperse dyes, and is subjected to high temperature and high pressure dyeing to obtain a polyester fabric with a gradient dyeing effect; The cross-sectional shape of the dynamic profiled yarn changes periodically along the length direction, and the cross-sectional shape of the single yarn in each period is in turn circular, flat and triangular. The preparation method of the dynamic profiled yarn is as follows: the polyester melt sprayed from the spinneret is first cooled to 200-240 DEG C in the spinning duct to obtain a preliminarily shaped single yarn, and then the preliminarily shaped single yarn is subjected to periodic cold air impact of 0-20 DEG C in the spinning duct, so that the temperature of the impacted area is reduced to 70-80 DEG C within 10-50 ms, and then the single yarn coming out of the spinning duct is subjected to bundling, drawing and setting, oiling and winding in turn to obtain the dynamic profiled yarn. The cold air impact is realized by a single yarn cold air dynamic profiled nozzle system installed in the spinning duct. The single yarn cold air dynamic profiled nozzle system comprises a nozzle module and a control system; the control system comprises solenoid valves, nozzle switch controllers and cold air pressure regulating valves; the nozzle module is composed of a plurality of nozzles, each nozzle being used for applying cold air impact to a single yarn, each nozzle having a plurality of annularly and uniformly distributed air outlets on it, and the air outlets being directed to the peripheral surface of the single yarn; a solenoid valve is installed on the pipeline corresponding to each air outlet, and all the solenoid valves are connected to the nozzle switch controllers through cables; the nozzles are connected to a total air inlet pipe through air pipes, and a cold air pressure regulating valve is installed at the inlet of the total air inlet pipe. The number of air outlets on each nozzle is 6, and the periodic cold air impact means that two air outlets are first opened to simultaneously impact the single yarn from opposite sides for 20-50 ms, then three air outlets arranged uniformly along the circumference are switched on to simultaneously impact the single yarn for 10-25 ms, and the cold air impact process is repeated after an interval of 5-100 ms. The process parameters of the high temperature and high pressure dyeing are as follows: dye bath pressure 0.15-0.3 MPa, bath ratio 1:8-20, mass fraction of disperse dyes 2-5%, dosage of disperse dye auxiliaries 0.5-1.5% (owf), and the fabric is subjected to rotation at a frequency of 3-5 r / min during the 120-130 DEG C holding stage. After dyeing, the fabric is subjected to cold water washing, warm water washing to remove floating color, and then reduction cleaning, and finally dried to obtain a polyester fabric with a gradient dyeing effect; wherein the cold water temperature is 15-25 DEG C, and the warm water temperature is 40-50 DEG C.

2. A process for the preparation of polyester fabric with gradual dyeing effect as claimed in claim 1 wherein, In each period along the length direction of the dynamic profiled yarn, the length ratio of the circular cross-section, the flat cross-section and the triangular cross-section is 1:0.2-10:0.1-5.

3. A process for the preparation of polyester fabric with gradual dyeing effect as claimed in claim 2, wherein the process further comprises the step of: The color difference of the regions with different cross-sectional shapes of the dynamic profiled yarn is greater than or equal to 2 levels, and the color difference of the adjacent regions with different dyeing effects of the polyester fabric with a gradient dyeing effect is greater than or equal to 1.5 levels.

4. A process for the preparation of polyester fabric with gradual dyeing effect as claimed in claim 1 wherein, The diameter of the spinning hole on the spinneret is 0.1-0.3 mm; the temperature of the polyester melt is 280-300 DEG C; and the spinning speed is 10-18 m / min.

5. A process for the preparation of polyester fabric with gradual dyeing effect as claimed in claim 4, wherein the said process is characterized by, The diameter of the air outlet hole of each nozzle is 0.05-0.2 mm, and the diameter of the filament inlet hole of the nozzle for passing the single filament is 0.2-0.6 mm.

6. The method for preparing a polyester fabric with a gradient dyeing effect according to claim 5, characterized in that, The primary cooling is carried out by ring blowing or side blowing, the cooling air temperature is 20-30 DEG C, and the cooling air speed is 0.8-1.5 m / s.

7. A process for the preparation of polyester fabric with gradual dyeing effect as claimed in claim 6 wherein, The height of the nozzle module from the ring blowing or side blowing area is 30-80 cm.

8. A process for the preparation of polyester fabric with gradual dyeing effect as claimed in claim 1, wherein, The heat setting temperature is 180-220 DEG C.