A method for preparing hollow elastic yarn

Abstract

The invention discloses a preparation method of a hollow elastic yarn, which belongs to the technical field of yarn preparation. The method comprises the following steps: a first step, adding a composite component slurry to a polyurethane solution, stirring evenly, and obtaining a spandex spinning solution; a second step, passing the spandex spinning solution through a spinneret, and performing dry spinning to obtain spandex fiber; a third step, using water-soluble polyvinyl alcohol fiber as a core yarn and spandex fiber as an outer fiber, and performing spinning treatment on an FA506 type ring spindle fine sand machine to obtain a core-spun yarn; a fourth step, placing the core-spun yarn in water and performing a core-dissolving treatment to obtain the hollow elastic yarn. The invention uses water-soluble polyvinyl alcohol fiber as a core yarn and spandex fiber as an outer fiber, and obtains the hollow yarn by a core-dissolving method. The preparation method is simple, does not involve high-temperature treatment, does not affect the use performance of the spandex yarn, and imparts good warmth retention, antibacterial, flame retardant and other properties to the yarn.

Description

Technical Field

[0001] The invention belongs to the technical field of yarn preparation, and particularly relates to a method for preparing hollow elastic yarn. Background Art

[0002] Hollow fiber refers to a chemical fiber with a tubular cavity along the fiber axis. It can be used in winter clothes, bedding, and padding. The hollow fiber structure contains a large amount of static air, which can bring light elasticity, good moisture permeability and comfortable warmth to the fabric. It is widely used in thermal underwear, sportswear, outdoor sports, blankets and other fields.

[0003] With the further development of spandex application technology, the demand for the versatility of spandex is also gradually increasing. For example, Chinese patent CN114164519A discloses a hollow spandex and a preparation method thereof. The preparation method comprises the following steps: preparing a prepolymer; dissolving the prepolymer, adding an amine chain extender to carry out a chain extension reaction, obtaining a polyurethane polymer solution by a terminator, adding auxiliary materials to the polyurethane polymer solution, stirring, and standing for aging to obtain a spandex spinning solution; degassing the spandex spinning solution, and spinning using a U-shaped or C-shaped spinneret. During the spinning process, air or nitrogen is filled into the fiber cavity, and the fiber is then false-twisted, oiled, and wound to obtain a spandex fiber with a hollow structure. This patent uses high-temperature gas to form the fiber into a hollow fiber, but polyurethane is prone to thermal decomposition at high temperatures, which shortens its service life. Therefore, it is necessary to provide a new method for preparing hollow elastic yarn. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing hollow elastic yarn, which uses water-soluble polyvinyl alcohol fiber as the core yarn and spandex fiber obtained by spinning a polyurethane spinning solution with added composite components as the outer fiber. The hollow yarn is obtained by a core-dissolving method. The preparation method is simple, does not involve high-temperature treatment, does not affect the performance of the spandex yarn, and gives the yarn good antibacterial and flame retardant properties.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a hollow elastic yarn comprises the following steps:

[0007] The first step is to pass the spandex spinning solution through a spinneret for dry spinning to obtain spandex fiber;

[0008] The second step is to use water-soluble polyvinyl alcohol fiber as the core yarn and spandex fiber as the outer fiber, with the mass ratio of water-soluble polyvinyl alcohol fiber to spandex fiber being 1-3:7-9, and to spin the yarn on a FA506 ring spindle fine sand machine to obtain core-spun yarn;

[0009] The third step is to place the core-spun yarn in water for core dissolving treatment to obtain the hollow elastic yarn.

[0010] As a further technical solution of the present invention, the spandex spinning solution is obtained by the following steps:

[0011] The polyether diol and diisocyanate are mixed and reacted at 70-95°C for 2 hours to obtain a prepolymer. The prepolymer is added to a polar amide solvent and stirred evenly. A diamine is added, and the molar ratio of the amino group to the isocyanate group in the system is controlled to be 1.02-1.08:1. The reaction is carried out for 1.5-2 hours to obtain a polyurethane solution. Thereafter, the composite component slurry is added and stirred evenly to obtain a spandex spinning solution.

[0012] As a further technical solution of the present invention, the mass ratio of the prepolymer to the polar amide solvent is 30-55:45-70.

[0013] As a further technical solution of the present invention, the amount of the composite component is 5-12% of the mass of the polyurethane solution, and the composite component slurry is composed of the composite component and the polar amide solvent in a mass ratio of 35-50:80-100.

[0014] As a further technical solution of the present invention, the composite component is obtained by the following steps:

[0015] S1, add 3-chloropropionaldehyde and ethyl acetate to a flask, stir, add 2-formaldehyde pyridine in an ice-water bath, stir and react at room temperature for 12-24 hours, filter, and recrystallize the filter cake with anhydrous ethanol to obtain a dialdehyde quaternary ammonium salt compound;

[0016] S2. Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, DMSO, and a dialdehyde quaternary ammonium salt compound to a flask, disperse them ultrasonically for 5 minutes, react at 150° C. for 12 hours under argon protection, and remove DMSO by distillation under reduced pressure to obtain a Schiff base polymer;

[0017] S3. Add the Schiff base polymer to anhydrous ethanol, add the ethanol solution of phosphorous acid dropwise with stirring, and after the addition is completed, stir and react at 70-75°C for 5 hours, then add the ethanol solution of copper nitrate trihydrate, and react at 76-78°C for 2-3 hours. After the reaction is completed, remove the anhydrous ethanol by rotary evaporation to obtain a composite component.

[0018] Using 3-chloropropionaldehyde and 2-formylpyridine as raw materials, a substitution reaction is performed in the presence of ethyl acetate to obtain a dialdehyde quaternary ammonium salt compound, which belongs to the A2 type monomer, where A is the aldehyde group, and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine as the B3 type monomer, where B is the amino group. A hyperbranched Schiff base polymer rich in pyridine quaternary ammonium salt structure, triazine ring and benzene ring is obtained through the condensation reaction between the amino group and the aldehyde group. Subsequently, the strong reducing property of phosphorous acid is utilized to reduce the Schiff base structure to form numerous -C-NH- groups while introducing phosphorus hydroxyl groups. Finally, copper ions are introduced through the good complexing property of phosphorus hydroxyl groups for metal ions to obtain a composite component.

[0019] As a further technical solution of the present invention, the molar ratio of 3-chloropropionaldehyde to 2-formylpyridine in S1 is 1:1.

[0020] As a further technical solution of the present invention, the mass ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to the dialdehyde quaternary ammonium salt compound in S2 is 2.1-2.4:1.8.

[0021] As a further technical solution of the present invention, the mass ratio of the Schiff base polymer, phosphorous acid and copper nitrate trihydrate in S3 is 3.8-4.0:0.8-1.2:2.5-3.4, the ethanol solution of phosphorous acid is composed of phosphorous acid and anhydrous ethanol in a dosage ratio of 0.8-1.2 g:50 mL, and the ethanol solution of copper nitrate trihydrate is composed of copper nitrate trihydrate and anhydrous ethanol in a dosage ratio of 2.5-3.4 g:50 mL.

[0022] As a further technical solution of the present invention, the molar ratio of polyether diol to diisocyanate is 1:1.5-2.0, the polyether diol is polytetramethylene ether diol with a number average molecular weight of 1000-3000, and the diisocyanate is one or more of 2,4'-diphenylmethane diisocyanate, a mixture of 4,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate.

[0023] Polytetramethylene ether glycol is used as a raw material, and the chain segments have high flexibility and regularity. The main chain does not contain unsaturated bonds and there are no ester groups on the main chain. The products have good hydrolysis resistance and physical properties.

[0024] As a further technical solution of the present invention, the polar amide solvent is one or both of N,N-dimethylacetamide and N,N-dimethylformamide, and the diamine is one or both of ethylenediamine and butanediamine.

[0025] As a further technical solution of the present invention, dry spinning uses a spinneret with 5 holes, a hole diameter of 0.4 mm, and an aspect ratio of 3:1; the air volume ratio of upper inlet / upper return / lower return = 0.65 / 0.35 / 0.25; the spinning temperature of upper shaft / middle shaft / lower shaft = 255-260℃ / 235-240℃ / 196-198℃; and a spinning shaft with a speed of 900m / min is used to spin 40 denier spandex fiber.

[0026] As a further technical solution of the present invention, the water-soluble polyvinyl alcohol fiber has a fineness of 1.5-3D, a length of 38-51 mm, and a core dissolving treatment water temperature of 50° C., and is purchased from Kuraray Trading (Shanghai) Co., Ltd.

[0027] Beneficial effects of the present invention:

[0028] The present invention provides a method for preparing a hollow elastic yarn. The hollow yarn is obtained by a core-dissolving method using water-soluble polyvinyl alcohol fiber as a core yarn and spandex fiber as an outer fiber. The preparation method is simple, does not involve high-temperature treatment, does not affect the performance of the spandex yarn, and imparts the yarn with good thermal insulation, antibacterial, flame retardant and other properties.

[0029] Among them, spandex fiber is obtained by dry spinning of a polyurethane spinning solution modified by a composite component. The composite component has the low viscosity characteristics of a hyperbranched polymer and has good dispersibility in the polyurethane solution. Its highly branched structure can introduce abundant intramolecular cavities into the yarn matrix, which, on the one hand, plays a good toughening role, and on the other hand, utilizes the stabilization and coating effects of the cavity on free radicals to improve the aging resistance of the yarn; in addition, the composite component also contains amino, hydroxyl, triazine structure, benzene ring, pyridinium quaternary ammonium salt structure. Amino, hydroxyl and other groups can form strong hydrogen bonds with polyurethane, thereby improving the elasticity and thermal stability of the yarn. The presence of triazine structure and benzene ring can, on the one hand, improve the UV resistance of the yarn, and on the other hand, improve the heat resistance of the yarn; more importantly, the composite component is also rich in nitrogen and phosphorus elements, which can play a synergistic flame retardant role with copper ions. Combined with the inhibitory effect of copper ions and pyridinium quaternary ammonium salt structure on bacteria, the obtained hollow yarn has good antibacterial properties;

[0030] In summary, the hollow elastic yarn prepared by the present invention not only has good mechanical properties, but also has excellent aging resistance, antibacterial and flame retardant properties, and has high practical value. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1

[0033] A composite component is obtained by the following steps:

[0034] S1. Add 0.1 mol of 3-chloropropionaldehyde and 150 mL of ethyl acetate to a flask, stir, then add 0.1 mol of 2-formaldehyde pyridine in an ice-water bath, stir and react at room temperature for 12 h, filter, and recrystallize the filter cake with anhydrous ethanol to obtain a dialdehyde quaternary ammonium salt compound;

[0035] S2. Add 2.1 g of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 60 mL of DMSO, and 1.8 g of a dialdehyde quaternary ammonium salt compound to a flask, disperse ultrasonically for 5 min, react at 150° C. under argon protection for 12 h, and remove DMSO by distillation under reduced pressure to obtain a Schiff base polymer;

[0036] S3. Add 3.8 g of Schiff base polymer to 40 mL of anhydrous ethanol, and add dropwise a solution consisting of 0.8 g of phosphorous acid and 50 mL of anhydrous ethanol while stirring. After the addition is completed, stir and react at 70°C for 5 hours. Then add a solution consisting of 2.5 g of copper nitrate trihydrate and 50 mL of anhydrous ethanol, and react at 76°C for 2 hours. After the reaction is completed, remove the anhydrous ethanol by rotary evaporation to obtain a composite component.

[0037] Example 2

[0038] A composite component is obtained by the following steps:

[0039] S1. Add 0.1 mol of 3-chloropropionaldehyde and 200 mL of ethyl acetate to a flask, stir, then add 0.1 mol of 2-formaldehyde pyridine in an ice-water bath, stir and react at room temperature for 24 h, filter, and recrystallize the filter cake with anhydrous ethanol to obtain a dialdehyde quaternary ammonium salt compound;

[0040] S2. Add 2.4 g of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 80 mL of DMSO, and 1.8 g of a dialdehyde quaternary ammonium salt compound to a flask, disperse ultrasonically for 5 min, react at 150° C. under argon protection for 12 h, and remove DMSO by distillation under reduced pressure to obtain a Schiff base polymer;

[0041] S3. Add 4.0 g of Schiff base polymer to 60 mL of anhydrous ethanol, and add dropwise a solution consisting of 1.2 g of phosphorous acid and 50 mL of anhydrous ethanol while stirring. After the addition is completed, stir and react at 75°C for 5 hours. Then add a solution consisting of 3.4 g of copper nitrate trihydrate and 50 mL of anhydrous ethanol, and react at 78°C for 3 hours. After the reaction is completed, remove the anhydrous ethanol by rotary evaporation to obtain a composite component.

[0042] Comparative Example 1

[0043] Compared with Example 1, 1.8 g of the dialdehyde quaternary ammonium salt compound in Example 1 was replaced by 1.2 g of terephthalaldehyde, and the remaining raw materials and preparation process were the same as in Example 1.

[0044] Comparative Example 2

[0045] Compared with Example 1, 2.1 g of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine in Example 1 was replaced with 0.7 g of 1,3,5-triaminobenzene, and the remaining raw materials and preparation process were the same as in Example 1.

[0046] Comparative Example 3

[0047] This comparative example is the Schiff base polymer obtained in step S2 of Example 1.

[0048] Example 3

[0049] A method for preparing a hollow elastic yarn comprises the following steps:

[0050] The first step is to mix polyether diol and diisocyanate, react at 70°C for 2 hours to obtain a prepolymer, add the prepolymer to N,N-dimethylacetamide at a mass ratio of 30:70, and stir evenly, add ethylenediamine, control the molar ratio of amino group to isocyanate group in the system to be 1.02:1, and react for 1.5 hours to obtain a polyurethane solution, then add the composite component slurry, stir evenly, and obtain a spandex spinning solution;

[0051] The amount of the composite component is 5% of the mass of the polyurethane solution, and the composite component slurry is composed of the composite component of Example 1 and N,N-dimethylacetamide in a mass ratio of 35:80;

[0052] The spandex spinning solution was then passed through a spinneret for dry spinning. The spinneret had five holes, a pore diameter of 0.4 mm, and an aspect ratio of 3:1. The air volume ratios (upper feed / upper return / lower return) were 0.65 / 0.35 / 0.25. The spinning temperatures (upper channel / middle channel / lower channel) were 255°C / 235°C / 196°C. Spinning was performed at a speed of 900 m / min in the spinning channel to produce 40-denier spandex fiber.

[0053] The second step is to use water-soluble polyvinyl alcohol fiber as the core yarn and spandex fiber as the outer fiber, with the mass ratio of water-soluble polyvinyl alcohol fiber to spandex fiber being 2:8, and to spin the yarn on a FA506 ring spinning machine to obtain core-spun yarn;

[0054] The third step is to place the core-spun yarn in 50° C. water for core dissolution treatment to obtain the hollow elastic yarn.

[0055] Among them, the molar ratio of polyether diol and diisocyanate is 1:1.5, the polyether diol is polytetramethylene ether diol with a number average molecular weight of 1000-3000, the diisocyanate is 2,4'-diphenylmethane diisocyanate, the water-soluble polyvinyl alcohol fiber has a fineness of 1.5-3D and a length of 38-51 mm, which is purchased from Kuraray Trading (Shanghai) Co., Ltd.

[0056] Example 4

[0057] A method for preparing a hollow elastic yarn comprises the following steps:

[0058] The first step is to mix polyether diol and diisocyanate, react at 85°C for 2 hours to obtain a prepolymer, add the prepolymer to N,N-dimethylformamide according to the mass ratio of prepolymer to N,N-dimethylformamide of 45:70, and stir evenly, add butanediamine, control the molar ratio of amino group to isocyanate group in the system to be 1.06:1, and react for 1.8 hours to obtain a polyurethane solution, then add the composite component slurry, stir evenly, and obtain a spandex spinning solution;

[0059] The amount of the composite component is 8% of the mass of the polyurethane solution, and the composite component slurry is composed of the composite component of Example 2 and N,N-dimethylformamide in a mass ratio of 40:90;

[0060] The spandex spinning solution was then passed through a spinneret for dry spinning. The spinneret had five holes, a pore diameter of 0.4 mm, and an aspect ratio of 3:1. The air volume ratios (upper feed / upper return / lower return) were 0.65 / 0.35 / 0.25. The spinning temperatures (upper channel / middle channel / lower channel) were 258°C / 238°C / 197°C. Spinning was performed at a speed of 900 m / min in the spinning channel to produce 40-denier spandex fiber.

[0061] The second step is to use water-soluble polyvinyl alcohol fiber as the core yarn and spandex fiber as the outer fiber, with the mass ratio of water-soluble polyvinyl alcohol fiber to spandex fiber being 2:8, and to spin the yarn on a FA506 ring spinning machine to obtain core-spun yarn;

[0062] The third step is to place the core-spun yarn in 50° C. water for core dissolution treatment to obtain the hollow elastic yarn.

[0063] Among them, the molar ratio of polyether diol and diisocyanate is 1:1.8, the polyether diol is polytetramethylene ether diol with a number average molecular weight of 1000-3000, the diisocyanate is 4,4'-diphenylmethane diisocyanate, the water-soluble polyvinyl alcohol fiber has a fineness of 1.5-3D and a length of 38-51 mm, which is purchased from Kuraray Trading (Shanghai) Co., Ltd.

[0064] Example 5

[0065] A method for preparing a hollow elastic yarn comprises the following steps:

[0066] The first step is to mix polyether diol and diisocyanate, react at 95°C for 2 hours to obtain a prepolymer, add the prepolymer to N,N-dimethylacetamide according to the mass ratio of prepolymer to N,N-dimethylacetamide of 55:70, and stir evenly, add butanediamine, control the molar ratio of amino group to isocyanate group in the system to be 1.08:1, and react for 2 hours to obtain a polyurethane solution, then add the composite component slurry, stir evenly, and obtain a spandex spinning solution;

[0067] The amount of the composite component is 12% of the mass of the polyurethane solution, and the composite component slurry is composed of the composite component of Example 2 and N,N-dimethylacetamide in a mass ratio of 50:100;

[0068] The spandex spinning solution was then passed through a spinneret for dry spinning. The spinneret had five holes, a pore diameter of 0.4 mm, and an aspect ratio of 3:1. The air volume ratios (upper inlet / upper return / lower return) were 0.65 / 0.35 / 0.25. The spinning temperatures (upper / middle / lower) were 260°C / 240°C / 198°C. Spinning was performed at a speed of 900 m / min in the spinning shaft to produce 40-denier spandex fiber.

[0069] The second step is to use water-soluble polyvinyl alcohol fiber as the core yarn and spandex fiber as the outer fiber, with the mass ratio of water-soluble polyvinyl alcohol fiber to spandex fiber being 3:8, and to spin the yarn on a FA506 ring spindle fine sand machine to obtain core-spun yarn;

[0070] The third step is to place the core-spun yarn in 50° C. water for core dissolution treatment to obtain the hollow elastic yarn.

[0071] Among them, the molar ratio of polyether diol and diisocyanate is 1:2.0, the polyether diol is polytetramethylene ether diol with a number average molecular weight of 1000-3000, the diisocyanate is 4,4'-diphenylmethane diisocyanate, the water-soluble polyvinyl alcohol fiber has a fineness of 1.5-3D and a length of 38-51 mm, which is purchased from Kuraray Trading (Shanghai) Co., Ltd.

[0072] Comparative Example 4

[0073] Compared with Example 3, the composite components in Example 3 were replaced by the substances in Comparative Example 1, and the remaining raw materials and preparation process were the same as in Example 3.

[0074] Comparative Example 5

[0075] Compared with Example 3, the composite components in Example 3 were replaced by the substances in Comparative Example 2, and the remaining raw materials and preparation process were the same as in Example 3.

[0076] Comparative Example 6

[0077] Compared with Example 3, the composite components in Example 3 were replaced by the substances in Comparative Example 3, and the remaining raw materials and preparation process were the same as in Example 3.

[0078] The hollow elastic yarns obtained in Examples 3 to 5 and Comparative Examples 4 to 6 were subjected to performance tests, and the test items were as follows:

[0079] Elasticity test: Each group of yarn samples was placed in a constant temperature and humidity chamber for 24 hours. The parameters were set according to the standard: effective clamping distance 500mm, stretching speed 500mm / min, expected tension 1N, stretching dwell time 30s, recovery dwell time 60s, and repeated stretching 3 times. The specific operation was carried out in accordance with the national standard GB / T3916-1997 to test the elastic recovery rate.

[0080] Flame retardant performance: Refer to the standard GB / T5454-1997 to test the limiting oxygen index;

[0081] Antibacterial performance: Refer to GB / T20994.3-2008 "Evaluation of antibacterial properties of textiles Part 3: Oscillation method" to test the inhibition rate of Staphylococcus aureus and Escherichia coli;

[0082] Yellowing resistance: Measured according to IOS11507:1997 (UVA light exposure for 168 hours), the color difference △E before and after the light exposure experiment is obtained and converted into a grade. The lower the grade, the worse the light resistance of the yarn.

[0083] The results are shown in Table 1:

[0084] Table 1

[0085]

[0086]

[0087] It can be seen from Table 1 that, compared with Comparative Examples 4, 5 and 6, the hollow elastic yarns obtained in Examples 4, 5 and 6 not only have good resilience, but also have excellent flame retardancy, antibacterial and yellowing resistance.

[0088] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0089] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a hollow elastic yarn, characterized in that: The following steps are involved: The first step is to mix polyether diol and diisocyanate, react at 70-95°C for 2 hours to obtain a prepolymer, add the prepolymer into a polar amide solvent and stir evenly, add diamine, control the molar ratio of amino group to isocyanate group in the system to be 1.02-1.08:1, and react for 1.5-2 hours to obtain a polyurethane solution, then add the composite component slurry, stir evenly, and obtain a spandex spinning solution; The second step is to pass the spandex spinning solution through a spinneret for dry spinning to obtain spandex fibers; The third step is to use water-soluble polyvinyl alcohol fiber as the core yarn and spandex fiber as the outer fiber, with the mass ratio of water-soluble polyvinyl alcohol fiber to spandex fiber being 1-3:7-9, and to spin the yarn on a FA506 ring spindle fine sand machine to obtain core-spun yarn; Step 4: placing the core-spun yarn in water for core dissolution treatment to obtain the hollow elastic yarn; The composite components are obtained by the following steps: The Schiff base polymer is added to anhydrous ethanol, and an ethanol solution of phosphorous acid is added dropwise with stirring. After the addition is completed, the mixture is stirred and reacted at 70-75°C for 5 hours. Then, an ethanol solution of copper nitrate trihydrate is added and reacted at 76-78°C for 2-3 hours to obtain a composite component. The Schiff base polymer is obtained by the following steps: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, DMSO and a dialdehyde quaternary ammonium salt compound were mixed and reacted at 150°C for 12 hours under argon protection to obtain a Schiff base polymer; The dialdehyde quaternary ammonium salt compound is obtained by the following steps: Add 3-chloropropanal and ethyl acetate to a flask, stir, then add 2-formaldehyde pyridine in an ice-water bath, and stir and react at room temperature for 12-24 hours to obtain a dialdehyde quaternary ammonium salt compound.

2. The method for preparing a hollow elastic yarn according to claim 1, wherein: The amount of the composite component is 5-12% of the mass of the polyurethane solution, and the composite component slurry is composed of the composite component and the polar amide solvent in a mass ratio of 35-50:80-100.

3. The method for preparing a hollow elastic yarn according to claim 1, wherein: The mass ratio of the Schiff base polymer, phosphorous acid and copper nitrate trihydrate is 3.8-4.0:0.8-1.2:2.5-3.

4.

4. The method for preparing a hollow elastic yarn according to claim 1, wherein: The mass ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to the dialdehyde quaternary ammonium salt compound is 2.1-2.4:1.

8.

5. The method for preparing a hollow elastic yarn according to claim 1, wherein: The molar ratio of 3-chloropropionaldehyde to 2-formylpyridine is 1:1.

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