A preparation process of hygroscopic polyester fiber yarn

Abstract

The present invention relates to the technical field of polyester, and discloses a preparation process of a hygroscopic polyester fiber yarn, wherein the present invention uses tris (2-aminoethyl) amine and 4-bromomethyl pyridine as raw materials, and obtains intermediate 1 through substitution reaction, and obtains intermediate 2 through addition reaction using intermediate 1 and bromobutyric acid, and then reacts it with 1,3-propanesulfonic acid lactone to obtain a hydrophilic modified quaternary ammonium salt intermediate. The present invention uses terephthalic acid, ethylene glycol, intermediate 2, etc. as raw materials to prepare hydrophilic modified polyester. Finally, hydrophilic modified polyester and hydrophilic modified quaternary ammonium salt intermediate are added to polyester slices, and polyester fiber is obtained through spinning and drawing. The polyester fiber yarn prepared by the present invention has excellent hygroscopicity and antibacterial properties.

Description

Technical Field

[0001] The invention relates to the technical field of polyester, in particular to a preparation process of a moisture-absorbing polyester fiber yarn. Background Art

[0002] Polyester fiber, also known as polyester fiber, is a synthetic fiber prepared by chemical polycondensation of organic dibasic acids and diols. It has excellent wrinkle resistance, shape retention, high modulus, mechanical properties, etc., and is widely used in clothing, home textiles, interior decoration and other fields. However, due to the regular macromolecular structure, good crystallization performance and lack of hydrophilic groups, polyester fiber has poor hydrophilicity and antibacterial properties. Therefore, the polyester yarn prepared from polyester also has poor hydrophilicity and antibacterial properties, which limits its development in clothing and other fields. Therefore, how to solve these problems is the focus of researchers' research.

[0003] Quaternary ammonium salts are compounds formed by replacing the four hydrogen atoms in the ammonium ion with hydrocarbon groups. They have excellent antibacterial properties and are widely used in the fields of fungicides, antistatic agents, flocculants, etc. Pyridine quaternary ammonium salts are ionic compounds bonded together by ionic bonds. They are generally prepared by a simple synthesis reaction of hydrocarbon alkylating agents and pyridine.

[0004] For example, the patent application publication number is CN 118087074 A, which provides an antibacterial polyester fiber and a preparation method thereof. The invention uses chitosan, quaternary ammonium salt, etc. as raw materials, and the prepared polyester fiber has excellent antibacterial and hydrophilic properties. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the deficiencies in the prior art, the present invention provides a process for preparing a hygroscopic polyester fiber yarn. The prepared polyester fiber yarn has excellent hygroscopic and antibacterial properties.

[0007] (II) Technical solution

[0008] A preparation process of a hygroscopic polyester fiber yarn, the preparation process comprising:

[0009] The polyester chips, hydrophilic modified polyester and hydrophilic modified quaternary ammonium salt intermediates are pre-crystallized under vacuum at 120-140°C for 3-6 hours, heated to 145-150°C and dried for 36-72 hours. After the pre-crystallization, the fibers are spun on a twin-screw high-speed composite spinning machine. The nascent fibers are balanced for 10 hours and drawn on a parallel drawing machine to obtain polyester fibers. The fibers are then subjected to opening and cleaning, carding, drawing, roving, spinning and winding processes to obtain hygroscopic polyester fiber yarns.

[0010] Preferably, the mass ratio of the polyester chips, the hydrophilic modified polyester, and the hydrophilic modified quaternary ammonium salt intermediate is 100:50-100:5-20.

[0011] Preferably, in the spinning process, the spinneret specification is 0.3 mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700 m / min, and the spinning temperature is 270°C.

[0012] Preferably, in the stretching process, the temperature of the hot roller is 60° C., the setting temperature is 145° C., the stretching speed is 300 m / min, and the stretching multiple is 3.2.

[0013] Preferably, the preparation process of the hydrophilic modified polyester is:

[0014] S1. Add tris(2-aminoethyl)amine and 4-bromomethylpyridine to ethanol solvent, stir and disperse, heat to 70-90°C, stir and react for 36-72h. After the reaction is completed, evaporate under reduced pressure, wash, and recrystallize to obtain intermediate 1.

[0015] S2. Under nitrogen conditions, add intermediate 1 to acetonitrile solvent, stir and disperse, then add bromobutyric acid, raise the temperature to 40-55°C, stir and react for 12-24 hours. After the reaction is completed, evaporate the solvent, recrystallize, and obtain intermediate 2.

[0016] S3. Add intermediate 2 to ethanol solvent, stir and disperse, then add 1,3-propanesulfonic acid lactone thereto, stir and react at 60-80°C for 24-48 hours, after the reaction is completed, add sodium carbonate thereto, stir and react for 1-3 hours, after the reaction is completed, filter, distill under reduced pressure, and recrystallize to obtain a hydrophilic modified quaternary ammonium salt intermediate.

[0017] S4. Add terephthalic acid and ethylene glycol antimony (500ppm / g terephthalic acid) to ethylene glycol, stir and disperse, heat to 220-250°C, react for 2-5h. After the reaction, add intermediate 2, continue to react for 30-80min, heat to 270-290°C, continue to react for 2-4h. After the reaction, obtain hydrophilic modified polyester.

[0018] Preferably, in S1, the molar ratio of tris(2-aminoethyl)amine to 4-bromomethylpyridine is 1:3-3.5.

[0019] Preferably, in S2, the molar ratio of intermediate 1 to bromobutyric acid is 1:3.2-4.

[0020] Preferably, in S3, the molar ratio of intermediate 2, 1,3-propanesulfonate, and sodium carbonate is 1:3.5-4.5:3-4.

[0021] Preferably, in S4, the molar ratio of terephthalic acid, ethylene glycol and intermediate 2 is 1:1.2-1.6:0.02-0.1.

[0022] (III) Beneficial technical effects

[0023] The present invention uses tris (2-aminoethyl) amine and 4-bromomethyl pyridine as raw materials, and obtains intermediate 1 through substitution reaction. Intermediate 1 is used to react with bromobutyric acid through addition reaction to obtain intermediate 2, and then the intermediate is reacted with 1,3-propanesulfonic acid lactone to obtain a hydrophilic modified quaternary ammonium salt intermediate. The hydrophilic modified quaternary ammonium salt intermediate prepared by the present invention through a series of reactions has a simple preparation method and a novel structure. The present invention uses terephthalic acid, ethylene glycol, intermediate 2 and the like as raw materials to prepare hydrophilic modified polyester. Finally, the hydrophilic modified polyester and the hydrophilic modified quaternary ammonium salt intermediate are added to polyester chips, and hygroscopic polyester fiber yarn is obtained through spinning, drawing, cotton opening and cleaning, roving, spun yarn, winding and the like processes.

[0024] The hydrophilic modified polyester and hydrophilic modified quaternary ammonium salt intermediate prepared by the present invention contain more sulfonates and carboxylates, which can form hydrogen bonds with water molecules. When added to polyester and spun, the prepared polyester fiber yarn has excellent hydrophilic moisture absorption performance.

[0025] The hydrophilic modified polyester and the hydrophilic modified quaternary ammonium salt intermediate prepared by the present invention contain a large number of quaternary ammonium salt structures and pyridinium quaternary ammonium salt structures, both of which are antibacterial structures. When the hydrophilic modified polyester and the hydrophilic modified quaternary ammonium salt intermediate are added to polyester, the prepared polyester fiber yarn has excellent antibacterial performance. In addition, the hydrophilic modified polyester and the hydrophilic modified quaternary ammonium salt intermediate prepared by the present invention contain the same structure, both have good compatibility, and when the hydrophilic modified polyester and the hydrophilic modified quaternary ammonium salt intermediate are added to polyester, the antibacterial performance and the hydrophilic hygroscopic performance of the polyester fiber yarn can be better improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a preparation route for hydrophilic modified quaternary ammonium salt intermediates. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] S1. Add 0.2 mol of tris(2-aminoethyl)amine and 0.6 mol of 4-bromomethylpyridine to ethanol solvent, stir and disperse, heat to 80°C, stir and react for 72 hours. After the reaction is completed, evaporate under reduced pressure, wash, and recrystallize to obtain intermediate 1.

[0030] S2. Under nitrogen conditions, 0.1 mol of intermediate 1 was added to acetonitrile solvent, stirred and dispersed, and then 0.4 mol of bromobutyric acid was added thereto. The temperature was raised to 45°C, and the reaction was stirred for 24 hours. After the reaction was completed, the solvent was evaporated and recrystallized to obtain intermediate 2.

[0031] S3. Add 0.1 mol of intermediate 2 to ethanol solvent, stir and disperse, then add 0.42 mol of 1,3-propanesulfonic acid lactone, stir and react at 70°C for 48 hours. After the reaction, add 0.35 mol of sodium carbonate, stir and react for 2 hours. After the reaction, filter, distill under reduced pressure, and recrystallize to obtain a hydrophilic modified quaternary ammonium salt intermediate.

[0032] S4. Add 10 mol of terephthalic acid and ethylene glycol antimony to 14 mol of ethylene glycol, stir and disperse, heat to 220°C, react for 2 hours, and after the reaction, add 1 mol of intermediate 2, continue to react for 80 minutes, heat to 280°C, and continue to react for 2 hours. After the reaction, a hydrophilic modified polyester is obtained.

[0033] S5. 50g of polyester chips, 25g of hydrophilic modified polyester and 2.5g of hydrophilic modified quaternary ammonium salt intermediate are pre-crystallized under vacuum at 130°C for 5h, heated to 150°C and dried for 48h. After the pre-crystallization, the fibers are spun on a twin-screw high-speed composite spinning machine, wherein the spinneret specification is 0.3mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700m / min, the spinning temperature is 270°C, the nascent fibers are balanced for 10h, and then stretched on a parallel stretching machine, wherein the hot roller temperature is 60°C, the setting temperature is 145°C, the stretching speed is 300m / min, and the stretching multiple is 3.2 to obtain polyester fibers, which are then subjected to opening and cleaning, carding, drawing, roving, spun yarn and winding processes to obtain hygroscopic polyester fiber yarns.

[0034] Example 2

[0035] S1. Add 0.2 mol of tris(2-aminoethyl)amine and 0.7 mol of 4-bromomethylpyridine to ethanol solvent, stir and disperse, heat to 70°C, stir and react for 48 hours. After the reaction is completed, evaporate under reduced pressure, wash, and recrystallize to obtain intermediate 1.

[0036] S2. Under nitrogen conditions, 0.1 mol of intermediate 1 was added to acetonitrile solvent, stirred and dispersed, and then 0.35 mol of bromobutyric acid was added thereto. The temperature was raised to 55°C, and the reaction was stirred for 12 hours. After the reaction was completed, the solvent was evaporated and recrystallized to obtain intermediate 2.

[0037] S3. Add 0.1 mol of intermediate 2 to ethanol solvent, stir and disperse, then add 0.4 mol of 1,3-propanesulfonic acid lactone, stir and react at 60°C for 36 hours. After the reaction, add 0.3 mol of sodium carbonate, stir and react for 2 hours. After the reaction, filter, distill under reduced pressure, and recrystallize to obtain a hydrophilic modified quaternary ammonium salt intermediate.

[0038] S4. Add 10 mol of terephthalic acid and ethylene glycol antimony to 16 mol of ethylene glycol, stir and disperse, heat to 250°C, react for 5 hours. After the reaction, add 0.2 mol of intermediate 2, continue to react for 60 minutes, heat to 290°C, continue to react for 4 hours. After the reaction, a hydrophilic modified polyester is obtained.

[0039] S5. Pre-crystallize 50g of polyester chips, 30g of hydrophilic modified polyester and 5g of hydrophilic modified quaternary ammonium salt intermediate under vacuum at 130°C for 5h, heat to 150°C and dry for 36h. After that, spin on a twin-screw high-speed composite spinning machine, wherein the spinneret specification is 0.3mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700m / min, the spinning temperature is 270°C, the nascent fiber is balanced for 10h, and stretch on a parallel stretching machine, wherein the hot roller temperature is 60°C, the setting temperature is 145°C, the stretching speed is 300m / min, and the stretching multiple is 3.2 to obtain polyester fiber, and then through the processes of opening and cleaning cotton, carding cotton, drawing, roving, spun yarn and winding to obtain hygroscopic polyester fiber yarn.

[0040] Example 3

[0041] S1. Add 0.2 mol of tris(2-aminoethyl)amine and 0.65 mol of 4-bromomethylpyridine to ethanol solvent, stir and disperse, heat to 90°C, stir and react for 36 hours. After the reaction is completed, evaporate under reduced pressure, wash, and recrystallize to obtain intermediate 1.

[0042] S2. Under nitrogen conditions, 0.1 mol of intermediate 1 was added to acetonitrile solvent, stirred and dispersed, and then 0.32 mol of bromobutyric acid was added thereto. The temperature was raised to 55°C, and the reaction was stirred for 24 hours. After the reaction was completed, the solvent was evaporated and recrystallized to obtain intermediate 2.

[0043] S3. Add 0.1 mol of intermediate 2 to ethanol solvent, stir and disperse, then add 0.4 mol of 1,3-propanesulfonic acid lactone, stir and react at 80°C for 24 hours. After the reaction, add 0.4 mol of sodium carbonate, stir and react for 1 hour. After the reaction, filter, distill under reduced pressure, and recrystallize to obtain a hydrophilic modified quaternary ammonium salt intermediate.

[0044] S4. Add 10 mol of terephthalic acid and ethylene glycol antimony to 15 mol of ethylene glycol, stir and disperse, heat to 230°C, react for 4 hours. After the reaction, add 0.5 mol of intermediate 2, continue to react for 60 minutes, heat to 270°C, continue to react for 3 hours. After the reaction, a hydrophilic modified polyester is obtained.

[0045] S5. Pre-crystallize 50g of polyester chips, 40g of hydrophilic modified polyester and 6g of hydrophilic modified quaternary ammonium salt intermediate under vacuum at 140°C for 6h, heat to 150°C and dry for 36h. After that, spin on a twin-screw high-speed composite spinning machine, wherein the spinneret specification is 0.3mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700m / min, the spinning temperature is 270°C, the nascent fiber is balanced for 10h, and stretch on a parallel stretching machine, wherein the hot roller temperature is 60°C, the setting temperature is 145°C, the stretching speed is 300m / min, and the stretching multiple is 3.2 to obtain polyester fiber, and then through the processes of opening and cleaning cotton, carding cotton, drawing, roving, spun yarn and winding to obtain hygroscopic polyester fiber yarn.

[0046] Example 4

[0047] S1. Add 0.2 mol of tris(2-aminoethyl)amine and 0.68 mol of 4-bromomethylpyridine to ethanol solvent, stir and disperse, heat to 80°C, stir and react for 50 hours. After the reaction is completed, evaporate under reduced pressure, wash, and recrystallize to obtain intermediate 1.

[0048] S2. Under nitrogen conditions, 0.1 mol of intermediate 1 was added to acetonitrile solvent, stirred and dispersed, and then 0.4 mol of bromobutyric acid was added thereto. The temperature was raised to 45°C, and the reaction was stirred for 20 hours. After the reaction was completed, the solvent was evaporated and recrystallized to obtain intermediate 2.

[0049] S3. Add 0.1 mol of intermediate 2 to ethanol solvent, stir and disperse, then add 0.4 mol of 1,3-propanesulfonic acid lactone, stir and react at 65°C for 48 hours. After the reaction, add 0.35 mol of sodium carbonate, stir and react for 2 hours. After the reaction, filter, distill under reduced pressure, and recrystallize to obtain a hydrophilic modified quaternary ammonium salt intermediate.

[0050] S4. Add 10 mol of terephthalic acid and ethylene glycol antimony to 15 mol of ethylene glycol, stir and disperse, heat to 230°C, react for 5 hours. After the reaction, add 0.8 mol of intermediate 2, continue to react for 50 minutes, heat to 280°C, continue to react for 3 hours. After the reaction, a hydrophilic modified polyester is obtained.

[0051] S5. Pre-crystallize 50g of polyester chips, 45g of hydrophilic modified polyester and 8g of hydrophilic modified quaternary ammonium salt intermediate under vacuum at 120°C for 4h, heat to 145°C and dry for 72h. After that, spin on a twin-screw high-speed composite spinning machine, wherein the spinneret specification is 0.3mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700m / min, the spinning temperature is 270°C, the nascent fiber is balanced for 10h, and stretch on a parallel stretching machine, wherein the hot roller temperature is 60°C, the setting temperature is 145°C, the stretching speed is 300m / min, and the stretching multiple is 3.2 to obtain polyester fiber, and then through the processes of opening and cleaning cotton, carding cotton, drawing, roving, spun yarn and winding to obtain hygroscopic polyester fiber yarn.

[0052] Example 5

[0053] S1. Add 0.2 mol of tris(2-aminoethyl)amine and 0.65 mol of 4-bromomethylpyridine to ethanol solvent, stir and disperse, heat to 80°C, stir and react for 48 hours. After the reaction is completed, evaporate under reduced pressure, wash, and recrystallize to obtain intermediate 1.

[0054] S2. Under nitrogen conditions, 0.1 mol of intermediate 1 was added to acetonitrile solvent, stirred and dispersed, and then 0.35 mol of bromobutyric acid was added thereto. The temperature was raised to 40°C, and the reaction was stirred for 12 hours. After the reaction was completed, the solvent was evaporated and recrystallized to obtain intermediate 2.

[0055] S3. Add 0.1 mol of intermediate 2 to ethanol solvent, stir and disperse, then add 0.35 mol of 1,3-propanesulfonic acid lactone, stir and react at 70°C for 48 hours. After the reaction is completed, add 0.35 mol of sodium carbonate, stir and react for 3 hours. After the reaction is completed, filter, distill under reduced pressure, and recrystallize to obtain a hydrophilic modified quaternary ammonium salt intermediate.

[0056] S4. Add 10 mol of terephthalic acid and ethylene glycol antimony to 16 mol of ethylene glycol, stir and disperse, heat to 240°C, react for 3 hours. After the reaction, add 0.6 mol of intermediate 2, continue to react for 60 minutes, heat to 290°C, continue to react for 3 hours. After the reaction, a hydrophilic modified polyester is obtained.

[0057] S5. Pre-crystallize 50g of polyester chips, 50g of hydrophilic modified polyester and 10g of hydrophilic modified quaternary ammonium salt intermediate under vacuum at 130°C for 5h, heat to 150°C and dry for 48h. After that, spin on a twin-screw high-speed composite spinning machine, wherein the spinneret specification is 0.3mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700m / min, the spinning temperature is 270°C, the nascent fiber is balanced for 10h, and stretch on a parallel stretching machine, wherein the hot roller temperature is 60°C, the setting temperature is 145°C, the stretching speed is 300m / min, and the stretching multiple is 3.2 to obtain polyester fiber, and then through the processes of opening and cleaning cotton, carding cotton, drawing, roving, spun yarn and winding to obtain hygroscopic polyester fiber yarn.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that in step S5, no hydrophilic modified polyester is contained.

[0060] Comparative Example 2

[0061] The difference between this comparative example and Example 1 is that in step S5, no hydrophilic modified quaternary ammonium salt intermediate is contained.

[0062] The contact angle of polyester fiber yarn was tested at 25°C and 60% relative humidity using a contact angle meter. The amount of water added was 2 μL, the speed of water added was 1 μL / s, and the test was completed 10 seconds after contact.

[0063] According to GB / T20944, the antibacterial properties of polyester fiber yarn were tested using the agar plate diffusion method, and the test bacteria were Staphylococcus aureus and Escherichia coli.

[0064]

[0065] The smaller the surface contact angle, the better the hydrophilic effect. It can be seen from the table that the polyester fiber yarn prepared by the present invention has good hydrophilic performance. The antibacterial effect of Examples 1-5 is better than that of Comparative Examples 1-2. This is because Examples 1-5 contain hydrophilic modified quaternary ammonium salt intermediates and hydrophilic modified polyesters, and it can be seen from Examples 1-5 that with the increase of hydrophilic modified polyesters and hydrophilic modified quaternary ammonium salt intermediates, the antibacterial performance increases.

[0066] Weigh 50g of fiber yarn, place it at 25℃ and 65% relative humidity for 48h, weigh G, then place it in an oven at 110℃ to dry, weigh G0, calculate the moisture regain (%), moisture regain (%) = (G-G0) / G0.

[0067]

[0068]

[0069] The higher the moisture regain, the better the hydrophilic hygroscopic property. It can be seen from the table that the polyester fiber yarn prepared by the present invention has excellent hydrophilic hygroscopic property.

[0070] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A process for preparing hygroscopic polyester fiber yarn, characterized in that: The preparation process is: The polyester chips, hydrophilic modified polyester and hydrophilic modified quaternary ammonium salt intermediate are pre-crystallized for 3-6 hours under vacuum at 120-140°C, heated to 145-150°C, and dried for 36-72 hours. After the pre-crystallization, the pre-crystallized polyester chips are pre-crystallized on a twin-screw high-speed composite spinning machine, the nascent fibers are balanced for 10 hours, and drawn on a parallel drawing machine to obtain polyester fibers. The fibers are then subjected to opening and cleaning, carding, drawing, roving, spinning and winding processes to obtain hygroscopic polyester fiber yarns. The preparation process of the hydrophilic modified polyester is as follows: S1, adding tris(2-aminoethyl)amine and 4-bromomethylpyridine to an ethanol solvent, stirring and dispersing, heating to 70-90°C, stirring and reacting for 36-72h, and after the reaction, distilling under reduced pressure, washing, and recrystallizing to obtain intermediate 1; S2, under nitrogen conditions, adding intermediate 1 to acetonitrile solvent, stirring and dispersing, then adding bromobutyric acid thereto, heating to 40-55° C., stirring and reacting for 12-24 hours, after the reaction is completed, evaporating the solvent, and recrystallizing to obtain intermediate 2; S3, adding intermediate 2 to an ethanol solvent, stirring and dispersing, then adding 1,3-propanesulfonate thereto, stirring and reacting at 60-80° C. for 24-48 hours, and then adding sodium carbonate thereto, stirring and reacting for 1-3 hours after the reaction is completed. After the reaction is completed, filtering, vacuum distillation, and recrystallization are performed to obtain a hydrophilic modified quaternary ammonium salt intermediate; S4. Add terephthalic acid and antimony glycol to ethylene glycol, stir and disperse, heat to 220-250°C, react for 2-5h. After the reaction, add intermediate 2, continue to react for 30-80min, heat to 270-290°C, continue to react for 2-4h. After the reaction, obtain hydrophilic modified polyester.

2. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: The mass ratio of the polyester slice, the hydrophilic modified polyester and the hydrophilic modified quaternary ammonium salt intermediate is 100:50-100:5-20.

3. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: In the spinning process, the spinneret specification is 0.3 mm×36f, the spinneret hole aspect ratio is 1:2, the spinning speed is 700 m / min, and the spinning temperature is 270°C.

4. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: The process conditions for stretching on the parallel stretching machine are: a hot roller temperature of 60° C., a setting temperature of 145° C., a stretching speed of 300 m / min, and a stretching multiple of 3.

2.

5. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: In the S1, the molar ratio of tris(2-aminoethyl)amine to 4-bromomethylpyridine is 1:3-3.

5.

6. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: In S2, the molar ratio of intermediate 1 to bromobutyric acid is 1:3.2-4.

7. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: In S3, the molar ratio of the intermediate 2, 1,3-propanesulfonate, and sodium carbonate is 1:3.5-4.5:3-4.

8. The process for preparing the hygroscopic polyester fiber yarn according to claim 1, characterized in that: In S4, the molar ratio of terephthalic acid, ethylene glycol and intermediate 2 is 1:1.2-1.6:0.02-0.1.

Images