Preparation method of black polyester deepened fiber and black polyester deepened fiber

Abstract

The invention discloses a preparation method of black polyester deepened fibers and the black polyester deepened fibers. The preparation method comprises the following steps: extruding a black polyester melt from a spinneret orifice, and coating a pre-spinning oil agent to obtain black polyester undrawn yarns; the black polyester undrawn yarn is subjected to damp and hot drafting in a low-refractive-index resin water-based emulsion, and then is subjected to air hot drafting to obtain a black polyester drawn yarn coated with low-refractive-index resin; the black polyester drawn yarn is subjected to tension heat setting, high-temperature curling, post-spinning oil agent coating and relaxation heat setting, and the black polyester deepening fiber with the black and white index L value not higher than 17.8 is obtained. The black polyester undrawn yarn is subjected to damp and hot drafting in the low-refractive-index resin water-based emulsion, so that the low-refractive-index resin can be uniformly coated on the surface of the black polyester fiber, the free volume among macromolecules of the black polyester fiber is increased under the heating condition, and part of low-refractive-index resin molecules are diffused into the surface layer of the black polyester fiber; the interface bonding force between the black polyester fiber and the low-refractive-index resin is improved.

Description

Technical Field

[0001] The present invention belongs to the field of synthetic fiber production. Specifically, it relates to a preparation method of black polyester deepening fiber and the black polyester deepening fiber. Background Art

[0002] The spun-dyed fiber can be processed into textiles without the need for a dyeing process, which has a prominent effect of reducing emissions and carbon. It is estimated that, compared with traditional post-spinning dyed polyester fibers, each ton of spun-dyed polyester fibers processed into textiles can reduce wastewater emissions by 32 tons and carbon dioxide emissions by 1.2 tons. Benefiting from industrial upgrading and the drive of energy conservation and emission reduction policies, the output of spun-dyed fibers has increased rapidly in recent years and has become a major variety of differential polyester fibers, among which black fibers account for more than 80%. The colorant used in the spun-dyed black polyester fiber is mainly carbon black pigment. Compared with organic colorants, the coloring ability of carbon black pigment is relatively weak, resulting in the color of the spun-dyed black polyester fiber being lighter than that of traditional post-spinning dyed polyester fibers.

[0003] Finishing with a low refractive index resin is one of the methods to improve the color depth of textile fabrics. By finishing with a low refractive index resin, the reflection of light on the surface of the textile fabric can be reduced, allowing more incident light to enter the interior of the textile and be absorbed by the colorant in the synthetic fiber, thereby achieving the effect of deepening the color.

[0004] However, most of the existing resin finishing applications have complex processes and strict conditions, and are basically directly applied to textile fabrics, making it difficult to apply to polyester fibers that have not been woven into fabrics. In addition, the bonding strength between the resin layer formed after finishing and the fiber is limited and may peel off during use processes such as washing and friction, resulting in the problem that the color of the fiber gradually fades during use, and the deepening effect is not durable enough.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a preparation method of black polyester deepening fiber and the black polyester deepening fiber, and the black polyester deepening fiber has the performance characteristics of high blackness and high fixing fastness of the low refractive index resin layer.

[0007] To solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0008] The first object of the present invention is to provide a preparation method of black polyester deepening fiber, including the following steps:

[0009] (1) The black polyester melt is extruded from the spinneret holes and coated with a pre-spinning oil agent to obtain an unstretched black polyester filament;

[0010] (2) The black polyester undrawn yarn is subjected to wet-heat drawing in an aqueous emulsion of a low refractive index resin, and then air heat drawing is carried out to obtain a black polyester drawn yarn coated with the low refractive index resin;

[0011] (3) The black polyester drawn yarn is subjected to tension heat setting, high-temperature crimping, and relaxation heat setting to obtain a black polyester deepening fiber with a black and white index L value not higher than 17.8 and a soaping color fastness not lower than grade 4-5.

[0012] In the present invention, the black polyester undrawn yarn is subjected to wet-heat drawing in an aqueous emulsion of a low refractive index resin, which can uniformly coat the low refractive index resin on the surface of the black polyester fiber. Moreover, under heating conditions, the free volume between the macromolecules of the black polyester fiber increases, and some low refractive index resin molecules will diffuse into the surface layer of the black polyester fiber, which can improve the interfacial bonding force between the black polyester fiber and the low refractive index resin.

[0013] Under the high-temperature baking and drying of hot air and hot rollers in the air heat drawing, tension heat setting process, high-temperature crimping process, and relaxation heat setting process, the aqueous emulsion of the low refractive index resin coated on the outer layer of the black polyester fiber will transform and form a film for fixation, reducing the light reflectivity on the fiber surface, enabling more incident light to enter the fiber interior and be absorbed by the carbon black pigment, thereby achieving the effect of deepening the color.

[0014] Further, in the step (2), the refractive index of the aqueous emulsion of the low refractive index resin is not higher than 1.5;

[0015] Preferably, the mass fraction of the low refractive index resin in the aqueous emulsion of the low refractive index resin is 2-6%;

[0016] Preferably, the low refractive index resin is selected from one or more of cationic acrylic resin, polyether-modified silicone resin, quaternized silicone resin, quaternized fluorosilicone resin, amino-modified silicone resin, and amino-modified fluorosilicone resin.

[0017] The refractive index of the low refractive index resin in the aqueous emulsion of the low refractive index resin is controlled within a range less than 1.5. Through the high-temperature baking and drying of hot air and hot rollers in the air heat drawing process, tension heat setting process, high-temperature crimping process, and relaxation heat setting process, a resin film with a refractive index not higher than 1.5 can be formed on the surface of the black polyester fiber, which can be reduced by more than 0.23 compared with the refractive index of 1.73 of the polyester fiber. Thus, it can achieve reducing the light reflection on the surface of the black polyester fiber, enabling more incident light to enter the fiber interior and be absorbed by the carbon black pigment, thereby achieving the effect of deepening the color.

[0018] In addition, controlling the content of the low refractive index resin in the aqueous emulsion of the low refractive index resin within the range of 2-6% can endow it with good surface coating performance on the black polyester fiber.

[0019] Further, in the step (2), first remove the pre-spinning oil agent of the black polyester undrawn yarn, and then conduct the first wet-heat drawing of the tow in the aqueous emulsion of the low refractive index resin by a first drawing machine; subsequently, draw it to a hot air heating box by a second drawing machine for the second air hot drawing to obtain the black polyester drawn yarn coated with the low refractive index resin.

[0020] Before coating the emulsion of the low refractive index resin, removing the pre-spinning oil agent on the surface of the black polyester fiber is beneficial to improving the interfacial bonding force between the low refractive index resin and the surface of the black polyester fiber.

[0021] In addition, moving the post-spinning oil agent coating process to after the high-temperature crimping process can further avoid the influence of the spinning oil agent on the fixation of the low refractive index resin film on the surface of the black polyester fiber, and can further ensure the fixation fastness of the low refractive index resin film on the surface of the black polyester fiber.

[0022] Preferably, in the step (2), after bundling the black polyester undrawn yarn, draw it into a water bath to remove the pre-spinning oil agent, and then conduct the first wet-heat drawing in the wet drawing bath of the aqueous emulsion of the low refractive index resin by a first drawing machine, and then draw it into a hot air heating box by a second drawing machine for the second hot drawing to obtain the black polyester drawn yarn coated with the low refractive index resin.

[0023] Preferably, the temperature of the water in the water bath is 50 - 80°C.

[0024] After the black polyester undrawn yarn is bundled by a wire guide frame and enters the water bath through a wire guiding machine, controlling the temperature of the water in the water bath within the range of 50 - 80°C can make the pre-spinning oil agent have good diffusibility in the water bath, so that the pre-spinning oil agent coated on the fiber surface is fully removed, which is beneficial to improving the fixation fastness of the subsequent low refractive index resin on the fiber surface.

[0025] Further, in the step (2), the temperature of the aqueous emulsion of the low refractive index resin is 60 - 80°C, and the wet-heat drawing multiple is 2.91 - 3.70.

[0026] When conducting the wet-heat drawing, controlling the temperature of the aqueous emulsion of the low refractive index resin at 60 - 80°C and the drawing ratio within the range of 2.91 - 3.70, the aqueous emulsion of the low refractive index resin can diffuse into the space between the macromolecules of the black polyester fiber, play a lubricating role in the slippage of the polyester macromolecular chains under high magnification stretching conditions, and further make the disordered macromolecular chains in the black polyester fiber stretch and highly orient along the fiber axis.

[0027] Further, in the step (2), the temperature of the hot air in the air hot drawing is 140 - 160°C, and the air hot drawing multiple is 1.08 - 1.20.

[0028] During air hot drawing, hot air at a high temperature of 140 - 160°C is used as the drawing medium, and the drawing ratio is controlled within the range of 1.08 - 1.29. This can further improve the orientation degree of the macromolecular chains of the black polyester fiber along the fiber axis, form partial crystallization, and achieve preliminary shaping. In addition, during the air hot drawing process, the hot air in the hot air heating box is directly sprayed onto the surface of the tow through flow control, which can promote the rapid drying of the aqueous emulsion of the low refractive index resin coated on the surface of the black polyester fiber.

[0029] Furthermore, in the step (1), the mass fraction of carbon black in the black polyester melt is 1.2 - 3.0%.

[0030] Preferably, in the step (1), the temperature of the black polyester melt is 280 - 290°C, and the winding speed for preparing the black polyester undrawn filament is 1000 - 1400 m / min.

[0031] Furthermore, in the step (3), the temperature of the hot roller of the tension heat setting machine is 180 - 210°C, and the residence time of the tow in the tension heat setting machine is 12 - 20 seconds.

[0032] Controlling the temperature of the hot roller of the tension heat setting machine within the range of 180 - 210°C and the residence time of the tow within the range of 12 - 20 seconds can, on the one hand, further improve the fixing fastness of the low refractive index resin on the surface of the black polyester fiber; on the other hand, it can further improve the perfection degree of the supramolecular structure inside the fiber, release the internal stress of the fiber, and improve the dimensional stability of the fiber.

[0033] Furthermore, in the step (3), the temperature of the hot roller for high temperature crimping is 120 - 140°C.

[0034] Preferably, the temperature of the tow is controlled at 120 - 140°C by the hot roller traction machine through the crimping temperature.

[0035] Controlling the temperature of the low refractive index resin coated black polyester tension heat set filament at 120 - 140°C by the hot roller traction machine through the crimping temperature can prevent the black polyester fiber from sticking under the action of the crimping pressure, and at the same time ensure the activity of the macromolecular chains of the tension heat set filament with both high crystallinity and high orientation degree, so that it can undergo crimping deformation under the mechanical pressure of the crimping knife.

[0036] In addition, by adjusting the temperature of the black polyester fiber tow through the hot roller traction machine, the black polyester fiber can be continuously maintained at a temperature conducive to the fixing of the low refractive index resin on the surface, which is beneficial to the improvement of its fixing fastness.

[0037] Furthermore, in the step (3), during the relaxation heat setting process, the baking and setting temperature of the relaxation heat setting machine is 100 - 130°C, and the residence time of the tow in the relaxation heat setting machine is 6 - 10 minutes.

[0038] The baking and setting temperature of the relaxation heat setting machine is controlled within the range of 100 - 130 °C, and the residence time of the tow is controlled within 6 - 10 minutes. On the one hand, it can further improve the fixing fastness of the low refractive index resin on the surface of the black polyester fiber. On the other hand, it can fully release the internal stress of the black polyester fiber and further improve its dimensional stability.

[0039] The present invention also provides a black polyester deepening fiber, which includes a black polyester fiber matrix and a low refractive index resin layer wrapped on the surface of the black polyester fiber matrix. The L value of the black - white index of the black polyester deepening fiber is not higher than 17.8, and the soaping color fastness is not lower than 4 - 5 levels;

[0040] Preferably, the carbon black content of the black polyester deepening fiber is 1.2 - 3.0%;

[0041] Preferably, the black polyester deepening fiber is prepared by the preparation method of the black polyester deepening fiber according to any one of claims 1 - 9.

[0042] After adopting the above - mentioned technical solution, the present invention has the following beneficial effects compared with the prior art.

[0043] The black polyester deepening staple fiber provided by the present invention is prepared by subjecting an oil - free black polyester undrawn yarn to wet - heat drawing in a low refractive index resin emulsion with a refractive index not higher than 1.5, and then successively through an air heat drawing process, a tension heat setting process, a high - temperature crimping process, and a relaxation heat setting process for baking and drying. A firmly fixed low refractive index resin film can be formed on the surface of the black polyester fiber, which can reduce the reflection of light on the fiber surface, enable more incident light to enter the fiber interior and be absorbed by the carbon black pigment, thereby achieving the effect of deepening. Detailed Embodiments

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments are described clearly and completely below. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0045] Embodiment 1

[0046] The preparation of the black polyester deepening fiber in this embodiment is carried out according to the following steps:

[0047] (1) The black polyester melt with a carbon black content of 1.2% is extruded from the spinneret holes, coated with a spinning - front oil agent, and wound into a bucket to obtain black polyester undrawn yarn, where the temperature of the black polyester melt is 290 °C and the winding speed is 1400 m / min;

[0048] (2) After bundling the black polyester undrawn filaments prepared in step (1) through a godet frame, they enter a water bath through a godet machine to fully remove the spinning oil agent. Then, they are subjected to wet heat drawing in a low refractive index resin aqueous emulsion drawing bath by a first draw frame and a second draw frame. Subsequently, they enter a hot air heating box through the second draw frame, and the filaments are subjected to air hot drawing in the hot air heating box between the second draw frame and a tension heat setting machine to obtain black polyester drawn filaments coated with a low refractive index resin.

[0049] Among them, the temperature of the water in the water bath is 80 °C; the temperature of the low refractive index resin aqueous emulsion is 80 °C, and the wet heat drawing ratio is 2.91; in the hot air heating box, hot air is directly sprayed onto the surface of the filaments through flow control as the air hot drawing medium, the temperature of the hot air is 160 °C, and the air hot drawing ratio is 1.20; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the cationic acrylic resin is 4%.

[0050] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 210 °C and the residence time of the filament bundle is 12 seconds.

[0051] (4) After adjusting the temperature of the black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) by a coiling temperature adjusting hot roller traction machine, they sequentially enter a high-temperature coiling process and a post-spinning oil agent coating process and then enter a relaxation heat setting machine for baking and setting to obtain black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature of the black polyester tension heat set filaments coated with a low refractive index resin after temperature adjustment by the coiling temperature adjusting hot roller traction machine is 130 °C, the baking and setting temperature of the relaxation heat setting machine is 120 °C, and the residence time of the filament bundle is 6 minutes.

[0052] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are subjected to a cutting process and a packing process to obtain finished black polyester deepening staple fibers.

[0053] Example 2

[0054] The preparation of black polyester deepening fibers in this example is carried out according to the following steps:

[0055] (1) The black polyester melt with a carbon black content of 1.5% is extruded from a spinneret hole, coated with a spinning oil agent, and wound into a bucket to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 288 °C and the winding speed is 1320 m / min;

[0056] (2) After bundling the black polyester undrawn filaments prepared in step (1) through a godet frame, they enter a water bath through a godet machine to fully remove the spinning oil agent. Then, they are subjected to wet heat drawing in a low refractive index resin aqueous emulsion drawing bath by a first draw frame and a second draw frame, and then enter a hot air heating box through the second draw frame, so that the filament bundle undergoes air hot drawing in the hot air heating box between the second draw frame and the tension heat setting machine, obtaining black polyester drawn filaments coated with a low refractive index resin.

[0057] Among them, the temperature of the water in the water bath is 80 °C; the temperature of the low refractive index resin aqueous emulsion is 80 °C, and the wet heat drawing ratio is 3.14; in the hot air heating box, hot air is directly sprayed onto the surface of the filament bundle through flow control as the air hot drawing medium, the temperature of the hot air is 160 °C, and the air hot drawing ratio is 1.18; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the cationic acrylic resin is 6%.

[0058] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 210 °C and the residence time of the filament bundle is 20 seconds.

[0059] (4) After adjusting the temperature of the black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) by a coiling temperature adjusting hot roller traction machine, they enter a relaxation heat setting machine for baking and setting through a high-temperature coiling process and a post-spinning oil agent coating process in sequence, obtaining black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature after adjusting the temperature of the black polyester tension heat set filaments coated with a low refractive index resin by the coiling temperature adjusting hot roller traction machine is 140 °C, the baking and setting temperature of the relaxation heat setting machine is 130 °C, and the residence time of the filament bundle is 10 minutes.

[0060] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are obtained as finished black polyester deepening staple fibers through a cutting process and a packing process.

[0061] Example 3

[0062] The preparation of black polyester deepening fibers in this example is carried out according to the following steps:

[0063] (1) The black polyester melt with a carbon black content of 1.8% is extruded from the spinneret holes, coated with a spinning oil agent, and wound into a bucket to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 286 °C and the winding speed is 1270 m / min;

[0064] (2) The black polyester undrawn filaments prepared in step (1) are bundled by a godet frame, enter a water bath through a godet machine, and the spinning oil agent from the previous process is completely removed. Then, they enter a low refractive index resin aqueous emulsion drawing bath through a first draw frame and a second draw frame for wet heat drawing. After that, they enter a hot air heating box through the second draw frame, and the filaments are subjected to air heat drawing in the hot air heating box between the second draw frame and a tension heat setting machine to obtain black polyester drawn filaments coated with a low refractive index resin.

[0065] Among them, the temperature of the water in the water bath is 70°C; the temperature of the low refractive index resin aqueous emulsion is 70°C, and the wet heat drawing ratio is 3.21; in the hot air heating box, hot air is directly sprayed onto the surface of the filament bundle through flow control as the air heat drawing medium, the temperature of the hot air is 150°C, and the air heat drawing ratio is 1.17; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the cationic acrylic resin is 4%.

[0066] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 200°C and the residence time of the filament bundle is 16 seconds.

[0067] (4) The black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) are temperature-adjusted by a coiling temperature-adjusting hot roller drawing machine, and then enter a relaxation heat setting machine for baking and setting through a high-temperature coiling process and a post-spinning oil agent coating process to obtain black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature of the black polyester tension heat set filaments coated with a low refractive index resin after being temperature-adjusted by the coiling temperature-adjusting hot roller drawing machine is 130°C, the baking and setting temperature of the relaxation heat setting machine is 120°C, and the residence time of the filament bundle is 8 minutes.

[0068] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are obtained as finished black polyester deepening staple fibers through a cutting process and a packing process.

[0069] Example 4

[0070] The preparation of black polyester deepening fibers in this example is carried out according to the following steps:

[0071] (1) The black polyester melt with a carbon black content of 2.0% is extruded from a spinneret hole, coated with a spinning oil agent from the previous process, and wound into a bucket to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 286°C and the winding speed is 1240 m / min;

[0072] (2) After the black polyester undrawn filaments prepared in step (1) are bundled by a godet frame and enter a water bath through a godet machine to fully remove the spinning oil agent, they then enter a low refractive index resin aqueous emulsion drawing bath through a first drawing machine and a second drawing machine for wet heat drawing, and then enter a hot air heating box through the second drawing machine, so that the tow is subjected to air heat drawing in the hot air heating box between the second drawing machine and the tension heat setting machine to obtain black polyester drawn filaments coated with a low refractive index resin.

[0073] Among them, the temperature of the water in the water bath is 70°C; the temperature of the low refractive index resin aqueous emulsion is 70°C, and the wet heat drawing ratio is 3.25; in the hot air heating box, hot air is directly sprayed onto the surface of the tow through flow control as the air heat drawing medium, the hot air temperature is 150°C, and the air heat drawing ratio is 1.17; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the cationic acrylic resin is 4%.

[0074] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 200°C and the residence time of the tow is 16 seconds.

[0075] (4) After the black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) are temperature-adjusted by a coiling temperature-adjusting hot roller traction machine, they sequentially pass through a high-temperature coiling process and a post-spinning oil agent coating process and enter a relaxation heat setting machine for baking and setting to obtain black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature of the black polyester tension heat set filaments coated with a low refractive index resin after being temperature-adjusted by the coiling temperature-adjusting hot roller traction machine is 130°C, the baking and setting temperature of the relaxation heat setting machine is 120°C, and the residence time of the tow is 8 minutes.

[0076] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are obtained as finished black polyester deepening staple fibers through a cutting process and a packing process.

[0077] Example 5

[0078] The preparation of the black polyester deepening fiber in this example is carried out according to the following steps:

[0079] (1) The black polyester melt with a carbon black content of 2.4% is extruded from the spinneret holes, coated with a spinning oil agent, and wound into a barrel to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 283°C and the winding speed is 1160 m / min;

[0080] (2) The black polyester undrawn filaments prepared in step (1) are bundled by a godet frame, enter a water bath through a godet machine to fully remove the spinning oil agent, and then enter a low refractive index resin aqueous emulsion drawing bath through a first draw frame and a second draw frame for wet heat drawing. Then, they enter a hot air heating box through the second draw frame, and the filaments are subjected to air heat drawing in the hot air heating box between the second draw frame and the tension heat setting machine to obtain black polyester drawn filaments coated with a low refractive index resin.

[0081] Among them, the temperature of the water in the water bath is 50°C; the temperature of the low refractive index resin aqueous emulsion is 60°C, and the wet heat drawing ratio is 3.39; in the hot air heating box, hot air is directly sprayed onto the surface of the filaments through flow control as the air heat drawing medium, the temperature of the hot air is 140°C, and the air heat drawing ratio is 1.15; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the cationic acrylic resin is 3%.

[0082] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 190°C and the residence time of the filaments is 16 seconds.

[0083] (4) The black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) are temperature-adjusted by a coiling temperature-adjusting hot roller traction machine, and then enter a relaxation heat setting machine for baking and setting through a high-temperature coiling process and a post-spinning oil agent coating process to obtain black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature of the black polyester tension heat set filaments coated with a low refractive index resin after being temperature-adjusted by the coiling temperature-adjusting hot roller traction machine is 130°C, the baking and setting temperature of the relaxation heat setting machine is 110°C, and the residence time of the filaments is 8 minutes.

[0084] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are obtained as finished black polyester deepening staple fibers through a cutting process and a packing process.

[0085] Example 7

[0086] The preparation of black polyester deepening fibers in this example is carried out according to the following steps:

[0087] (1) The black polyester melt with a carbon black content of 3.0% is extruded from the spinneret holes, coated with a spinning oil agent, and wound into a bucket to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 280°C and the winding speed is 1000 m / min;

[0088] (2) The black polyester undrawn filaments prepared in step (1) are bundled by a godet frame, enter a water bath through a godet machine to fully remove the oiling agent for pre-spinning, and then enter a wet heat drawing bath of a low refractive index resin aqueous emulsion through a first drawing machine and a second drawing machine for wet heat drawing. Then, they enter a hot air heating box through the second drawing machine, and the filaments are subjected to air heat drawing in the hot air heating box between the second drawing machine and a tension heat setting machine to obtain black polyester drawn filaments coated with a low refractive index resin.

[0089] Among them, the temperature of the water in the water bath is 60°C; the temperature of the low refractive index resin aqueous emulsion is 70°C, and the wet heat drawing ratio is 3.70; in the hot air heating box, the hot air is directly sprayed onto the surface of the filaments through flow control as the air heat drawing medium, the temperature of the hot air is 150°C, and the air heat drawing ratio is 1.08; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the polyether-modified silicone resin is 2%.

[0090] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 180°C and the residence time of the filaments is 16 seconds.

[0091] (4) After the temperature of the black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) is adjusted by a coiling temperature adjusting hot roller traction machine, they sequentially enter a high-temperature coiling process and an oiling agent coating process for post-spinning, and then enter a relaxation heat setting machine for baking and setting to obtain black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature of the black polyester tension heat set filaments coated with a low refractive index resin after being adjusted by the coiling temperature adjusting hot roller traction machine is 120°C, the baking and setting temperature of the relaxation heat setting machine is 100°C, and the residence time of the filaments is 8 minutes.

[0092] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are subjected to a cutting process and a packing process to obtain finished black polyester deepening staple fibers.

[0093] The preparation of the black polyester deepening fibers in this example is carried out according to the following steps:

[0094] (1) The black polyester melt with a carbon black content of 1.2% is extruded from the spinneret holes, coated with an oiling agent for pre-spinning, and wound into a bucket to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 290°C and the winding speed is 1400 m / min;

[0095] (2) The black polyester undrawn filaments prepared in step (1) are bundled through a godet frame, enter a water bath through a godet machine to fully remove the spinning oil agent, and then enter a wet heat drawing bath of a low refractive index resin aqueous emulsion through a first drawing machine and a second drawing machine for wet heat drawing. Then, they enter a hot air heating box through the second drawing machine, and the filament bundle is subjected to air hot drawing in the hot air heating box between the second drawing machine and the tension heat setting machine to obtain black polyester drawn filaments coated with a low refractive index resin.

[0096] Among them, the temperature of the water in the water bath is 80 °C; the temperature of the low refractive index resin aqueous emulsion is 80 °C, and the wet heat drawing ratio is 2.91; in the hot air heating box, the hot air is directly sprayed onto the surface of the filament bundle through flow control as the air hot drawing medium, the temperature of the hot air is 160 °C, and the air hot drawing ratio is 1.20; the low refractive index resin in the low refractive index resin aqueous emulsion is a cationic acrylic resin with a refractive index not higher than 1.5, and the mass fraction of the cationic acrylic resin is 4%.

[0097] (3) The black polyester drawn filaments coated with a low refractive index resin prepared in step (2) are heat set by a tension heat setting machine to obtain black polyester tension heat set filaments coated with a low refractive index resin, where the temperature of the hot roller of the tension heat setting machine is 210 °C and the residence time of the filament bundle is 12 seconds.

[0098] (4) After the black polyester tension heat set filaments coated with a low refractive index resin prepared in step (3) are temperature adjusted by a coiling temperature adjusting hot roller traction machine, they sequentially pass through a high temperature coiling process and a post-spinning oil agent coating process and enter a relaxation heat setting machine for baking and setting to obtain black polyester relaxation heat set filaments coated with a low refractive index resin. Among them, the temperature of the black polyester tension heat set filaments coated with a low refractive index resin after being temperature adjusted by the coiling temperature adjusting hot roller traction machine is 130 °C, the baking and setting temperature of the relaxation heat setting machine is 120 °C, and the residence time of the filament bundle is 6 minutes.

[0099] (5) The black polyester relaxation heat set filaments coated with a low refractive index resin obtained in step (4) are obtained as finished black polyester deepening staple fibers through a cutting process and a packing process.

[0100] Comparative Example 1

[0101] (1) The black polyester melt with a carbon black content of 1.2% is extruded from a spinneret hole, coated with a spinning oil agent, and wound into a bucket to obtain black polyester undrawn filaments, where the temperature of the black polyester melt is 290 °C and the winding speed is 1400 m / min;

[0102] (2) After bundling the black polyester undrawn filaments prepared in step (1) through a godet frame, they enter an oiling bath through a godet machine to balance the spinning finish, and then undergo wet-heat drawing in a spinning finish drawing bath through a first drawframe and a second drawframe. Then, they enter a draw steam heating box through the second drawframe to perform steam hot drawing of the tow between the second drawframe and a tenter setting machine, obtaining black polyester drawn filaments. The temperature of the spinning finish in the oiling bath is 50°C, the temperature of the spinning finish in the spinning finish drawing bath is 70°C, the temperature of the steam in the draw steam heating box is 150°C, the first-stage hot drawing ratio is 2.91, and the second-stage hot drawing ratio is 1.20.

[0103] (3) The black polyester drawn filaments prepared in step (2) are set through a tenter setting machine to obtain black polyester tenter-set filaments. The temperature of the hot roller of the tenter setting machine is 210°C, and the residence time of the tow is 12 seconds.

[0104] (4) The black polyester tenter-set filaments prepared in step (3) are coated by spraying the post-spinning finish, the temperature is adjusted through a crimping steam heating box, then undergo a high-temperature crimping process and enter a relaxation setting machine for baking and setting, obtaining black polyester relaxation-set filaments. The temperature of the steam in the crimping steam heating box is 130°C, the baking and setting temperature of the relaxation setting machine is 80°C, and the residence time of the tow is 8 minutes.

[0105] (5) The black polyester relaxation-set filaments obtained in step (4) undergo a cutting process and a packing process to obtain the finished product of black polyester staple fibers.

[0106] Comparative Example 2

[0107] The difference between this comparative example and Example 1 is only that: in step (2), the aqueous emulsion of the low refractive index resin with a mass fraction of 4% is replaced by the aqueous emulsion of the low refractive index resin with a mass fraction of 0.5%.

[0108] Comparative Example 3

[0109] The difference between this comparative example and Example 1 is only that: in step (2), the aqueous emulsion of the low refractive index resin at 80°C is replaced by the aqueous emulsion of the low refractive index resin at 40°C.

[0110] Comparative Example 4

[0111] The difference between this comparative example and Example 1 is only that: in step (2), the process of removing the pre-spinning finish is not carried out.

[0112] Test Example 1

[0113] The polyester staple fibers prepared in the above Examples 1-6 and Comparative Examples 1-4 were tested for the black-and-white index L value. The test method was as follows: Weigh 1 g of the staple fiber sample to be tested. Manually comb the staple fibers smoothly and stack them layer by layer into the HunterLab loose fiber clip, ensuring that the staple fibers on the test surface are arranged neatly and smoothly. Then place the test surface of the HunterLab loose fiber clip on the measuring hole of the DATACOLOR400 spectrophotometer (D65 light source, 10° viewing angle, HunterLab color system) to measure the black-and-white index L value of the staple fiber sample. Take the average value of five groups of test data; Color fastness to soaping: The test method refers to GB / T 3921-2008.

[0114] The test results of this experiment are shown in Table 1.

[0115] Table 1:

[0116]

[0117] As can be seen from Table 1, the black-and-white index L values representing the blackness of the black polyester darkening staple fibers prepared in Examples 1-6 are all not higher than 17.8, and the color fastness to soaping grades representing the color fastness are all not lower than 4-5 grades, indicating that the finished black polyester darkening staple fibers have both high blackness characteristics and high fixing fastness of the low refractive index resin layer. The darkening effect imparted by the low refractive index resin film is basically not affected by use.

[0118] The black index L value of the black polyester staple fiber prepared in Comparative Example 1 is 19.0, and the color fastness to soaping is 4 grades. The carbon black content of the staple fibers prepared in Comparative Example 1 and Example 1 is both 1.2%. However, compared with the staple fibers prepared in Example 1, the black-and-white index L value of the staple fibers prepared in Comparative Example 1 is 1.2 higher, and the color fastness to soaping is reduced by 1 grade. Thus, it can be seen that after the black polyester darkening staple fibers prepared in Example 1 are subjected to wet-heat drawing in a low refractive index resin aqueous emulsion with a refractive index not higher than 1.5, and then successively through the air heat drawing process, the tension heat setting process, the high-temperature crimping process and the relaxation heat setting process for baking and drying, a firmly fixed low refractive index resin film is formed on the surface of the black polyester fiber, which can reduce the reflection of light on the fiber surface and enable more incident light to enter the fiber interior and be absorbed by the carbon black pigment, thereby achieving the darkening effect; at the same time, the low refractive index resin film firmly fixed on the surface of the black polyester staple fiber further improves the fastness of the carbon black pigment to soaping.

[0119] The blackness index L value of the black polyester deepening short fibers prepared in Comparative Example 2 was 18.7, and the soaping color fastness was 4-5 grades. Compared with Example 1, the mass content of carbon black in the raw materials was 1.2% in both cases, but the blackness index L value was 0.9 higher and the soaping color fastness decreased by half a grade. It can be seen that in the wet heat drawing process of Comparative Example 2, the mass fraction of the low refractive index resin in the aqueous emulsion of the low refractive index resin was reduced to 0.5%, resulting in a relatively thinner thickness of the low refractive index resin film fixed on the surface of the prepared black polyester deepening short fibers compared with Example 1, a relatively weakened deepening effect, and a decrease in the soaping color fastness.

[0120] The blackness index L value of the black polyester deepening short fibers prepared in Comparative Example 3 was 17.9, and the soaping color fastness was 4-5 grades. Compared with Example 1, the mass content of carbon black in the raw materials was 1.2% in both cases, but the soaping color fastness decreased by half a grade. It can be seen that in the wet heat drawing process of the black polyester deepening short fibers prepared in Comparative Example 3, the temperature of the aqueous emulsion of the low refractive index resin was reduced to 40°C, resulting in a relatively small free volume between the macromolecules of the black polyester fibers, making it difficult for the low refractive index resin molecules to diffuse into the surface layer of the black polyester fibers. As a result, the fixing fastness of the low refractive index resin on the fiber surface decreased, and during the soaping process, some of the low refractive index resin would fall off, causing the soaping color fastness to decrease by half a grade.

[0121] The blackness index L value of the black polyester deepening short fibers prepared in Comparative Example 4 was 18.0, and the soaping color fastness was 4 grades. Compared with Example 1, the mass content of carbon black in the raw materials was 1.2% in both cases, but the soaping color fastness decreased by 1 grade. It can be seen that in the preparation process of the black polyester deepening short fibers prepared in Comparative Example 4, the process of removing the spinning oil agent in the water bath was omitted, resulting in a decrease in the fixing fastness of the low refractive index resin coated on the fiber surface. During the soaping process, some of the low refractive index resin would fall off, causing the soaping color fastness to decrease by 1 grade.

[0122] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications using the technical content prompted above into equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the present invention's solution.

Claims

1. A preparation method of a black polyester deepening fiber, characterized in that, It includes the following steps: (1) The black polyester melt is extruded from the spinneret holes and coated with the pre-spinning oil agent to obtain black polyester undrawn filaments; (2) The black polyester undrawn filaments are subjected to wet-heat drawing in a water-based emulsion of a low refractive index resin, and then air heat drawing is carried out to obtain black polyester drawn filaments coated with the low refractive index resin; (3) The black polyester drawn filaments are subjected to tension heat setting, high-temperature crimping, coated with the post-spinning oil agent, and relaxation heat setting to obtain black polyester deepening fibers with a black-and-white index L value not higher than 17.8 and a soaping color fastness not lower than grade 4-5.

2. The preparation method of a black polyester deepening fiber according to claim 1, characterized in that, In the step (2), the refractive index of the water-based emulsion of the low refractive index resin is not higher than 1.5; Preferably, the mass fraction of the low refractive index resin in the water-based emulsion of the low refractive index resin is 2-6%; Preferably, the low refractive index resin is selected from one or more of cationic acrylic resin, polyether-modified silicone resin, quaternized silicone resin, quaternized fluorosilicone resin, amino-modified silicone resin, and amino-modified fluorosilicone resin.

3. The preparation method of a black polyester deepening fiber according to claim 1 or 2, characterized in that, In the step (2), first remove the pre-spinning oil agent of the black polyester undrawn filaments, and then carry out the first wet-heat drawing of the filament bundle in the water-based emulsion of the low refractive index resin by the first drawing machine; subsequently, it is drawn by the second drawing machine to the hot air heating box for the second air heat drawing to obtain black polyester drawn filaments coated with the low refractive index resin; Preferably, in the step (2), after the black polyester undrawn filaments are bundled, they are led into the water bath to remove the pre-spinning oil agent, and then the first wet-heat drawing is carried out in the drawing bath of the water-based emulsion of the low refractive index resin by the first drawing machine, and then it is led into the hot air heating box by the second drawing machine for the second heat drawing to obtain black polyester drawn filaments coated with the low refractive index resin; Preferably, the temperature of the water in the water bath is 50-80°C.

4. The preparation method of a black polyester deepening fiber according to any one of claims 1-3, characterized in that, In the step (2), the temperature of the water-based emulsion of the low refractive index resin is 60-80°C, and the wet-heat drawing multiple is 2.91-3.

70.

5. A method for preparing a black polyester deepening fiber according to any one of claims 1-4, characterized in that, In the step (2), the hot air temperature in the air heat drawing is 140-160°C, and the air heat drawing multiple is 1.08-1.

20.

6. The preparation method of a black polyester deepening fiber according to any one of claims 1-5, characterized in that, In the step (1), the mass fraction of carbon black in the black polyester melt is 1.2-3.0%; Preferably, in the step (1), the temperature of the black polyester melt is 280-290°C, and the winding speed for preparing the black polyester undrawn filaments is 1000-1400 m / min.

7. The preparation method of a black polyester deepening fiber according to any one of claims 1-6, characterized in that, In the step (3), the temperature of the hot roller of the tension heat setting machine is 180-210°C, and the residence time of the filament bundle in the tension heat setting machine is 12-20 seconds.

8. A method for preparing a black polyester deepening fiber according to any one of claims 1-7, characterized in that, In the step (3), the temperature of the hot roller for the high-temperature crimping is 120-140°C; Preferably, the temperature of the filament bundle is controlled at 120-140°C by the crimping temperature regulating hot roller traction machine.

9. The preparation method of a black polyester deepening fiber according to any one of claims 1-8, characterized in that, In the step (3), in the relaxation heat setting process, the baking and setting temperature of the relaxation heat setting machine is 100-130°C, and the residence time of the filament bundle in the relaxation heat setting machine is 6-10 minutes.

10. A black polyester deepening fiber, characterized in that, It includes a black polyester fiber matrix, and a low refractive index resin layer wrapped on the surface of the black polyester fiber matrix. The black-and-white index L value of the black polyester deepening fiber is not higher than 17.8, and the soaping color fastness is not lower than grade 4-5; Preferably, the carbon black content of the black polyester deepening fiber is 1.2 to 3.0%; Preferably, the black polyester deepening fiber is prepared by the preparation method of the black polyester deepening fiber according to any one of claims 1-9.

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