A highly absorbent venous care fiber that promotes microcirculation and its preparation method

Abstract

This application discloses a highly absorbent, microcirculation-promoting venous care fiber and its preparation method, relating to the field of polyester fiber technology. The fiber is composed of modified bio-based polyester chips and silane-modified far-infrared composite particles. The modified bio-based polyester is a multi-block copolymer formed by introducing polyethylene glycol-b-polylactic acid during the synthesis of bio-based polyester from 2,5-furandicarboxylic acid and ethylene glycol, through a transesterification reaction. The far-infrared composite particles are composed of various components such as nano-silica, iron oxide, and alumina. In the preparation process, the modified far-infrared composite particles and modified bio-based polyester chips are first prepared separately, and then melt-spun to obtain fibers with irregular cross-sections. This application solves the problems of easy loss of hydrophilic groups and decreased mechanical properties in existing highly absorbent far-infrared fibers. The resulting fiber possesses both durable high absorbency and good mechanical properties, and the matrix is ​​bio-based polyester, which is green and biodegradable, making it suitable for weaving venous care fabrics.

Description

Technical Field

[0001] This application relates to the field of polyester fiber technology, specifically to a highly absorbent venous care fiber that promotes microcirculation and its preparation method. Background Technology

[0002] With the aging population and the increasing number of people who sit or stand for long periods, the incidence of venous-related diseases such as varicose veins and venous thrombosis in the lower extremities is rising year by year. Venous care has become an important need in clinical rehabilitation and daily health maintenance. The core pathological feature of venous diseases is poor local blood circulation and blood stasis, which easily leads to discomfort such as limb edema, soreness, and pain, and in severe cases, skin ulcers. Clinical practice shows that gentle and sustained local warming can dilate blood vessels, accelerate blood flow, effectively promote microcirculation, and relieve venous discomfort symptoms. Among them, fabrics with far-infrared heating function can effectively achieve the effect of warming and caring for local areas of the human body. The fabric needs to have good moisture absorption to absorb sweat from the skin surface in time, avoid skin irritation or infection caused by dampness and heat, and improve the comfort of long-term wear. Therefore, venous care fabrics with high moisture absorption, gentle heating, and far-infrared radiation functions have become a research hotspot in the field of textile materials. Far-infrared functional fibers are the core carriers for achieving the functions of heating and promoting microcirculation in intravenous care. Existing technologies mostly prepare these fibers by blending far-infrared particles with a fiber matrix through spinning. However, the method of using far-infrared particles alone in combination with a fiber matrix cannot meet the requirements of intravenous care fabrics for moisture absorption and heat generation. Chinese invention patent CN109137531A discloses a polyester functional fiber that simultaneously possesses far-infrared properties, antistatic properties, and good moisture absorption. This invention adds far-infrared particles to a polyester matrix and uses gold nanoparticles as a dispersant to improve the dispersibility and antistatic properties of the far-infrared particles, resulting in a polyester functional fiber. Surface treatment of the fiber further enhances its moisture absorption properties. This polyester functional fiber exhibits excellent far-infrared heating, antistatic, and moisture absorption properties.

[0003] However, the high moisture-absorbing far-infrared fibers prepared by existing technologies are mostly modified by coating or blending to achieve hydrophilicity. The hydrophilic groups are easily migrated and lost from the fiber matrix, resulting in a decrease in fiber moisture absorption. Furthermore, in-situ grafting for hydrophilic modification can lead to a reduction in fiber mechanical properties. Therefore, there is an urgent need to develop a far-infrared fiber that combines both moisture absorption and mechanical properties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the primary objective of this application is to provide a highly absorbent, microcirculation-promoting venous care fiber and its preparation method. A low-molecular-weight pre-condensed bio-based polyester is obtained through the reaction of 2,5-furandicarboxylic acid and ethylene glycol. Then, polyethylene glycol-b-polylactic acid is added to the pre-condensed bio-based polyester to generate a modified bio-based polyester in situ. This modified bio-based polyester has a multi-block structure, where the hydrophilic soft segments and rigid hard segments provide the fiber with excellent hydrophilicity and mechanical properties. Simultaneously, surface-modified far-infrared composite particles are added to impart far-infrared heating properties to the fiber, resulting in a far-infrared fiber with high absorbency and good mechanical properties.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] In a first aspect, this application provides a highly absorbent, microcirculation-promoting venous care fiber, comprising modified bio-based polyester chips and modified far-infrared composite particles; the mass ratio of the modified bio-based polyester chips to the modified far-infrared composite particles is 100:(8-12).

[0007] The modified bio-based polyester chips were prepared by introducing polyethylene glycol-b-polylactic acid during the synthesis of bio-based polyester using 2,5-furandicarboxylic acid and ethylene glycol as raw materials.

[0008] The modified far-infrared composite particles are obtained by modifying the surface of far-infrared composite particles with silane.

[0009] Preferably, the far-infrared composite particles are composed of nano-silica, nano-iron oxide, nano-alumina, nano-magnesium oxide, nano-potassium oxide, and nano-platinum powder.

[0010] Preferably, the mass ratio of the nano-silica, nano-iron oxide, nano-alumina, nano-magnesium oxide, nano-potassium oxide and nano-platinum powder is (45-65):(6-18):(12-18):(3-8):(5-8):(3-6).

[0011] It should be noted that by combining multiple far-infrared emitting particles, a wider far-infrared spectrum can be covered, achieving a synergistic enhancement effect. Simultaneously, the proportions of each component take into account melting point, hardness, and compatibility with polymers, making the composite particles less prone to decomposition or spinneret clogging during melt spinning. In preparing the far-infrared composite particles, the various mineral raw materials are first mixed in proportion, and then processed into nanoparticles with an average particle size of less than 100 nm using a high-energy ball milling method, thus obtaining the far-infrared composite particles.

[0012] Preferably, the cross-sectional shape of the fiber is any one of cross-shaped, star-shaped, and trilobal.

[0013] Secondly, this application provides a method for preparing highly absorbent, microcirculation-promoting venous care fibers, comprising the following steps:

[0014] Modified far-infrared composite particles are obtained by modifying the far-infrared composite particles.

[0015] Preparation of modified bio-based polyester chips;

[0016] Modified bio-based polyester chips and modified far-infrared composite particles were mixed evenly and added to a melt spinning machine to prepare highly hygroscopic and microcirculation-promoting venous care fibers.

[0017] Preferably, the specific steps for modifying the far-infrared composite particles are as follows:

[0018] Add 2-3% KH-560 silane coupling agent (by mass of far-infrared composite particles) to a 95% ethanol aqueous solution. Adjust the pH to 4-5 with acetic acid and stir for 15-30 min. Then add 15% far-infrared composite particles (by mass of ethanol aqueous solution) and ultrasonically disperse at 300W power and 50-60℃ for 50-60 min to obtain a dispersion. Centrifuge the dispersion at 6000-8000 rpm for 10-15 min, collect the centrifuged precipitate, and wash the precipitate 2-4 times with anhydrous ethanol. Dry the precipitate at 70-80℃ for 4-6 h to obtain modified far-infrared composite particles.

[0019] It should be noted that modifying far-infrared composite particles with silane coupling agents to construct an organic coating layer on the particle surface can improve the compatibility and interfacial bonding between the particles and the fiber matrix. The alkoxy end of the silane coupling agent hydrolyzes to generate hydroxyl groups, which undergo a condensation reaction with the hydroxyl groups on the surface of the far-infrared particles to form chemical bonds. The epoxy group at the other end can react with the terminal hydroxyl / carboxyl groups of the polyester molecular chain during the subsequent melt spinning process, so that the inorganic particles are tightly bound to the organic matrix, avoiding particle agglomeration that would lead to spinning difficulties or a decline in fiber performance.

[0020] Preferably, the specific steps for preparing the modified bio-based polyester chips are as follows:

[0021] Under nitrogen protection, polyethylene glycol was added to a reaction vessel, and the mixture was heated to 115-125°C under reflux conditions. After stirring and melting, the mixture was vacuum dried for 25-35 minutes. Nitrogen gas was then introduced to restore atmospheric pressure. A 0.1 mol / L solution of stannous octoate toluene was added and stirred until homogeneous. L-lactide was then added and stirred until homogeneous. The mixture was heated to 125-135°C and reacted for 5-7 hours. The temperature was then lowered to 78-82°C, and dichloromethane was added to dissolve the precipitate, yielding solution A. Solution A was then added dropwise to anhydrous diethyl ether at 0°C at a rate of 48-96 mL / min. The precipitate was collected by filtration and vacuum dried to obtain polyethylene glycol-b-polylactic acid.

[0022] Under nitrogen protection, 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant were added to a reactor. Stirring was started at a rate of 140-150 rpm, and the temperature was increased to 175-185℃ at a rate of 2℃ / min. The temperature was maintained for 1-1.5 h, and then increased to 215-225℃ at a rate of 1℃ / min. The reaction was continued until the water output reached more than 95% of the theoretical value. The pressure was reduced to below 5 kPa within 25-35 min, and the reaction was continued for 0.8-1.2 h. The stirring rate was increased to 200-240 rpm to obtain a bio-based polyester prepolymer.

[0023] Under nitrogen protection, polyethylene glycol-b-polylactic acid was added to a reactor and mixed with bio-based polyester prepolymer. The mixture was stirred until homogeneous and the temperature was maintained at 215-225℃. The reaction was carried out at atmospheric pressure for 25-35 minutes. Then, the pressure was reduced to below 100 Pa within 25-35 minutes, the temperature was raised to 235-245℃, and the reaction was maintained at this temperature for 2-3 hours. Nitrogen gas was introduced to restore atmospheric pressure. The molten polymer was extruded, water-cooled, and sliced ​​to obtain modified bio-based polyester chips.

[0024] It should be noted that the monomer of 2,5-furandicarboxylic acid is first generated by the esterification reaction of 2,5-furandicarboxylic acid and ethylene glycol. Then, under low vacuum conditions, the monomer undergoes a polycondensation reaction to form a prepolymer. In the later stage of the polycondensation reaction, polyethylene glycol-b-polylactic acid is added. Its terminal hydroxyl groups undergo transesterification with the ester groups of the prepolymer, introducing the polyethylene glycol-b-polylactic acid segments into the bio-based polyester backbone to form a multi-block copolymer.

[0025] Preferably, the mass ratio of polyethylene glycol, stannous octanoate toluene solution, L-lactide, and dichloromethane is 100:(0.008-0.0082):(190-210):(65-67); the mass ratio of solution A to anhydrous diethyl ether is 1:10; the mass ratio of 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant is 100:(74-76):(0.08-0.1):(0.11-0.13); and the mass ratio of bio-based polyester prepolymer to polyethylene glycol-b-polylactic acid is 1:(1.9-2.1).

[0026] Preferably, the antioxidant is any one of antioxidant 1010, antioxidant 1076, and antioxidant 1098.

[0027] Preferably, the specific steps for preparing the highly absorbent, microcirculation-promoting venous care fiber are as follows:

[0028] Modified bio-based polyester chips and modified far-infrared composite particles were mixed evenly at a mass ratio of 30:(8-12), added to a twin-screw extruder, melted and extruded at 230-240℃ to obtain functional masterbatch.

[0029] Modified bio-based polyester chips and functional masterbatch were mixed evenly at a mass ratio of 70:(38-42) and then melt-spun. The spinning temperature was set as follows: Zone 1: 215-225℃, Zone 2: 225-235℃, Zone 3: 235-245℃, and the spinneret temperature was 235-240℃. The spun filaments were cooled by side blowing at 20-25℃ and a wind speed of 0.6-0.8m / s, and then drawn at a draw ratio of 3.8-4.5 at a draw temperature of 85-95℃. After drawing, the filaments were heat-set at 130-150℃ for 40-60s and then wound to obtain highly hygroscopic and microcirculation-promoting venous care fibers.

[0030] It should be noted that the highly absorbent and microcirculation-promoting vein care fiber, through the hydrophilic groups in the fiber, adsorbs water molecules and releases the kinetic energy of the water molecules, converting the kinetic energy into heat energy, thereby achieving the effect of moisture absorption and heat generation. The far-infrared composite particles achieve far-infrared heating under the dual effects of the fiber's own moisture absorption and heat generation and the human body's radiant heat, thus achieving the effect of vein care. By using a special-shaped spinneret to obtain a special-shaped cross-section of the highly absorbent and microcirculation-promoting vein care fiber, the specific surface area of ​​the fiber can be increased, enhancing the fiber's ability to adsorb water molecules and greatly improving the fiber's moisture absorption performance.

[0031] It should be noted that the highly absorbent and microcirculation-promoting venous care fiber prepared in this application can be used to weave venous care fabrics, which can alleviate varicose veins and provide functions such as warmth and knee protection.

[0032] The beneficial effects of this application are:

[0033] By adding synthesized polyethylene glycol-b-polylactic acid (PEG-b) during the esterification polycondensation reaction of 2,5-furandicarboxylic acid and ethylene glycol, and utilizing the transesterification reaction between PEG-b-polylactic acid's terminal hydroxyl groups and the ester groups of the prepolymer obtained from the polycondensation, PEG-b-polylactic acid segments are introduced into the bio-based polyester backbone, forming a multi-block copolymer. This allows for in-situ grafting of hydrophilic groups onto the bio-based polyester backbone, not only improving the hygroscopicity of the bio-based polyester but also preventing the migration and escape of hydrophilic groups, ensuring the durability of the fiber's hydrophilic properties. Furthermore, the rigid furan ring structure on the bio-based polyester molecular chain has relatively... The high modulus and strength, even after the addition of flexible hydrophilic segments, ensure that the fiber still retains good mechanical properties. By mixing and spinning hydrophilically modified bio-based polyester chips with modified far-infrared composite particles, far-infrared fibers with moisture-absorbing and heat-generating functions can be obtained. When water molecules combine with hydrophilic groups on the fiber matrix molecular chain, latent heat is released, which can promote the active heating of far-infrared particles and enhance the far-infrared heating effect of the fiber. The highly moisture-absorbing and microcirculation-promoting vein care fiber prepared by this method, with bio-based polyester as the matrix, has good biodegradability, is green and environmentally friendly, and does not pollute the environment. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A flowchart illustrating the preparation method of a highly absorbent, microcirculation-promoting venous care fiber provided in this application. Detailed Implementation

[0036] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0038] The following specific embodiments further illustrate this point:

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a method for preparing highly absorbent, microcirculation-promoting venous care fibers, including the following steps:

[0041] 1. The dried far-infrared composite particles were added to anhydrous ethanol to prepare a particle-ethanol mixture with a mass fraction of 15%. Then, KH560 (2% by mass of particles) was added, and the mixture was ultrasonically dispersed at 300W power and 55℃ for 55 min to obtain a dispersion. The dispersion was then centrifuged at 7000rpm for 12 min, and the centrifuged precipitate was collected. The precipitate was washed three times with anhydrous ethanol and dried at 75℃ for 5 h to obtain modified far-infrared composite particles. The far-infrared composite particles consist of 55% nano-silica, 15% nano-iron oxide, 12% nano-alumina, 6% nano-magnesium oxide, 7% nano-potassium oxide, and 5% nano-platinum powder by mass.

[0042] 2. Under nitrogen protection, polyethylene glycol was added to a reaction vessel. The mixture was refluxed and heated to 120°C. After melting by stirring, the reaction vessel was evacuated and dried for 30 minutes under the same conditions. Nitrogen was then introduced to restore atmospheric pressure. A 0.1 mol / L solution of stannous octoate toluene was added and stirred until homogeneous. L-lactide was added, and the mixture was stirred at 100 rpm for 10 minutes. The temperature was then raised to 130°C and reacted for 6 hours. The temperature was lowered to 80°C, and dichloromethane was added to dissolve the precipitate, yielding solution A. Solution A was then added dropwise to anhydrous diethyl ether at 0°C at a rate of 48 mL / min. The precipitate was collected by filtration and dried under vacuum to obtain polyethylene glycol-b-polylactic acid. The mass ratio of polyethylene glycol, stannous octoate toluene solution, L-lactide, and dichloromethane was 100:0.0081:200:66; the mass ratio of solution A to anhydrous diethyl ether was 1:10.

[0043] 3. Under nitrogen protection, 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1010 were added to a reactor. Stirring was started at 145 rpm, and the temperature was increased to 180°C at a rate of 2°C / min and held for 1.2 h. Then, the temperature was increased to 220°C at a rate of 1°C / min, and the reaction was continued until the water output reached more than 95% of the theoretical value. The pressure was reduced from atmospheric pressure to below 5 kPa within 30 min, and the reaction was continued for 1 h with the stirring rate increased to 220 rpm to obtain a bio-based polyester prepolymer. The mass ratio of 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1010 was 100:75:0.09:0.12.

[0044] 4. Under nitrogen protection, polyethylene glycol-b-polylactic acid (PEG-b-PLA) is added to a reactor and mixed with the bio-based polyester prepolymer. The mixture is stirred until homogeneous, and the temperature is maintained at 220°C. The reaction is carried out at atmospheric pressure for 30 minutes. Then, the pressure is reduced to below 100 Pa within 30 minutes, the temperature is raised to 240°C, and the reaction is maintained at this temperature for 2.5 hours. Nitrogen gas is introduced, and the atmospheric pressure is restored. The molten polymer is extruded, water-cooled, and sliced ​​to obtain modified bio-based polyester chips. The mass ratio of the bio-based polyester prepolymer to PEG-b-PLA is 1:2.

[0045] 5. Modified bio-based polyester chips and modified far-infrared composite particles are mixed evenly at a mass ratio of 30:11, added to a twin-screw extruder, melted and extruded at 235℃ to obtain functional masterbatch; modified bio-based polyester chips and functional masterbatch are mixed evenly at a mass ratio of 70:41 and melt-spun. The spinning temperature is set as follows: Zone 1: 220℃, Zone 2: 230℃, Zone 3: 240℃, and the spinneret temperature is 238℃. The spinneret cross-section shape is cross-shaped. The spun filaments are cooled by side blowing air at 23℃ and a wind speed of 0.7m / s, drawn at a draw ratio of 4, and drawn at a draw temperature of 90℃. After drawing, they are heat-set at 140℃ for 50s and wound to obtain highly hygroscopic and microcirculation-promoting vein care fibers.

[0046] Example 2

[0047] like Figure 1 As shown, this embodiment provides a method for preparing highly absorbent, microcirculation-promoting venous care fibers, including the following steps:

[0048] 1. The dried far-infrared composite particles were added to anhydrous ethanol to prepare a particle-ethanol mixture with a mass fraction of 15%. Then, KH560 (2.5% by mass of the particles) was added, and the mixture was ultrasonically dispersed at 300W power and 50℃ for 50 min to obtain a dispersion. The dispersion was then centrifuged at 6000rpm for 10 min, and the centrifuged precipitate was collected. The precipitate was washed twice with anhydrous ethanol and dried at 70℃ for 4 h to obtain modified far-infrared composite particles. The far-infrared composite particles consist of 45% nano-silica, 18% nano-iron oxide, 15% nano-alumina, 8% nano-magnesium oxide, 8% nano-potassium oxide, and 6% nano-platinum powder by mass.

[0049] 2. Under nitrogen protection, polyethylene glycol was added to a reaction vessel. The mixture was refluxed and heated to 115°C. After melting by stirring, the reaction vessel was evacuated and dried for 25 minutes under the same conditions. Nitrogen was then introduced to restore atmospheric pressure. A 0.1 mol / L solution of stannous octoate toluene was added and stirred until homogeneous. L-lactide was added, and the mixture was stirred at 100 rpm for 10 minutes. The temperature was then raised to 125°C and reacted for 5 hours. The temperature was lowered to 78°C, and dichloromethane was added to dissolve the precipitate, yielding solution A. Solution A was then added dropwise at a rate of 60 mL / min to anhydrous diethyl ether at 0°C. The precipitate was collected by filtration and dried under vacuum to obtain polyethylene glycol-b-polylactic acid. The mass ratio of polyethylene glycol, stannous octoate toluene solution, L-lactide, and dichloromethane was 100:0.008:190:65; the mass ratio of solution A to anhydrous diethyl ether was 1:10.

[0050] 3. Under nitrogen protection, 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1010 were added to a reactor. Stirring was started at 140 rpm, and the temperature was increased to 175°C at a rate of 2°C / min and held for 1 hour. Then, the temperature was increased to 215°C at a rate of 1°C / min. The reaction was continued until the water output reached more than 95% of the theoretical value. The pressure was reduced from atmospheric pressure to below 5 kPa within 25 minutes, and the reaction was continued for 0.8 hours. The stirring rate was increased to 200 rpm to obtain a bio-based polyester prepolymer. The mass ratio of 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1076 was 100:74:0.08:0.11.

[0051] 4. Under nitrogen protection, polyethylene glycol-b-polylactic acid (PEG-b-PLA) is added to a reactor and mixed with the bio-based polyester prepolymer. The mixture is stirred until homogeneous, and the temperature is maintained at 215°C. The reaction is carried out at atmospheric pressure for 25 minutes. Then, the pressure is reduced to below 100 Pa within 25 minutes, the temperature is raised to 235°C, and the reaction is maintained at this temperature for 2 hours. Nitrogen gas is introduced, and the atmospheric pressure is restored. The molten polymer is extruded, water-cooled, and sliced ​​to obtain modified bio-based polyester chips. The mass ratio of the bio-based polyester prepolymer to PEG-b-PLA is 1:1.9.

[0052] 5. Modified bio-based polyester chips and modified far-infrared composite particles are mixed evenly at a mass ratio of 30:8, added to a twin-screw extruder, melted and extruded at 230℃ to obtain functional masterbatch; modified bio-based polyester chips and functional masterbatch are mixed evenly at a mass ratio of 70:38 and melt-spun. The spinning temperature is set as follows: Zone 1: 215℃, Zone 2: 225℃, Zone 3: 235℃, and the spinneret temperature is 235℃. The spinneret cross-section shape is cross-shaped. The spun filaments are cooled by side blowing air at 20℃ and a wind speed of 0.6m / s, drawn at a draw ratio of 3.8, and drawn at a draw temperature of 85℃. After drawing, they are heat-set at 130℃ for 40s and wound to obtain highly hygroscopic and microcirculation-promoting vein care fibers.

[0053] Example 3

[0054] like Figure 1 As shown, this embodiment provides a method for preparing highly absorbent, microcirculation-promoting venous care fibers, including the following steps:

[0055] 1. The dried far-infrared composite particles were added to anhydrous ethanol to prepare a particle-ethanol mixture with a mass fraction of 15%. Then, KH560 (3% by mass of particles) was added, and the mixture was ultrasonically dispersed at 300W power and 60℃ for 60 min to obtain a dispersion. The dispersion was then centrifuged at 8000rpm for 15 min, and the centrifuged precipitate was collected. The precipitate was washed four times with anhydrous ethanol and dried at 80℃ for 6 h to obtain modified far-infrared composite particles. The far-infrared composite particles consist of 65% nano-silica, 6% nano-iron oxide, 18% nano-alumina, 3% nano-magnesium oxide, 5% nano-potassium oxide, and 3% nano-platinum powder by mass.

[0056] 2. Under nitrogen protection, polyethylene glycol was added to a reaction vessel. The mixture was refluxed and heated to 125°C. After melting by stirring, the reaction vessel was evacuated and dried for 35 minutes under the same conditions. Nitrogen was then introduced to restore atmospheric pressure. A 0.1 mol / L solution of stannous octoate toluene was added and stirred until homogeneous. L-lactide was added, and the mixture was stirred at 100 rpm for 10 minutes. The temperature was then raised to 135°C and reacted for 7 hours. The temperature was lowered to 82°C, and dichloromethane was added to dissolve the precipitate, yielding solution A. Solution A was then added dropwise to anhydrous diethyl ether at 0°C at a rate of 96 mL / min. The precipitate was collected by filtration and dried under vacuum to obtain polyethylene glycol-b-polylactic acid. The mass ratio of polyethylene glycol, stannous octoate toluene solution, L-lactide, and dichloromethane was 100:0.0082:210:67; the mass ratio of solution A to anhydrous diethyl ether was 1:10.

[0057] 3. Under nitrogen protection, 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1010 were added to a reactor. Stirring was started at 150 rpm, and the temperature was increased to 185°C at a rate of 2°C / min and held for 1.5 h. Then, the temperature was increased to 225°C at a rate of 1°C / min, and the reaction was continued until the water output reached more than 95% of the theoretical value. The pressure was reduced from atmospheric pressure to below 5 kPa within 35 min, and the reaction was continued for 1.2 h. The stirring rate was increased to 240 rpm to obtain a bio-based polyester prepolymer. The mass ratio of 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1098 was 100:76:0.1:0.13.

[0058] 4. Under nitrogen protection, polyethylene glycol-b-polylactic acid (PEG-b-PLA) is added to a reactor and mixed with the bio-based polyester prepolymer. The mixture is stirred until homogeneous, and the temperature is maintained at 225°C. The reaction is carried out at atmospheric pressure for 35 minutes. Then, the pressure is reduced to below 100 Pa within 35 minutes, the temperature is raised to 245°C, and the reaction is maintained at this temperature for 3 hours. Nitrogen gas is introduced, and the pressure is restored to atmospheric pressure. The molten polymer is extruded, water-cooled, and sliced ​​to obtain modified bio-based polyester chips. The mass ratio of the bio-based polyester prepolymer to PEG-b-PLA is 1:2.1.

[0059] 5. Modified bio-based polyester chips and modified far-infrared composite particles are mixed evenly at a mass ratio of 30:12, added to a twin-screw extruder, melted and extruded at 240℃ to obtain functional masterbatch; modified bio-based polyester chips and functional masterbatch are mixed evenly at a mass ratio of 70:42 and melt-spun. The spinning temperature is set as follows: Zone 1: 225℃, Zone 2: 235℃, Zone 3: 245℃, and the spinneret temperature is 240℃. The spinneret cross-section shape is star-shaped. The spun filaments are cooled by side blowing air at 25℃ and a wind speed of 0.8m / s, drawn at a draw ratio of 4.5, and drawn at a draw temperature of 95℃. After drawing, they are heat-set at 150℃ for 60s and wound to obtain highly hygroscopic and microcirculation-promoting vein care fibers.

[0060] Example 4

[0061] like Figure 1 As shown, this embodiment provides a method for preparing highly absorbent, microcirculation-promoting venous care fibers, including the following steps:

[0062] 1. The dried far-infrared composite particles were added to anhydrous ethanol to prepare a particle-ethanol mixture with a mass fraction of 15%. Then, KH560 (3% by mass of particles) was added, and the mixture was ultrasonically dispersed at 300W power and 55℃ for 55 min to obtain a dispersion. The dispersion was then centrifuged at 7000rpm for 12 min, and the centrifuged precipitate was collected. The precipitate was washed three times with anhydrous ethanol and dried at 75℃ for 5 h to obtain modified far-infrared composite particles. The far-infrared composite particles consist of 55% nano-silica, 15% nano-iron oxide, 12% nano-alumina, 6% nano-magnesium oxide, 7% nano-potassium oxide, and 5% nano-platinum powder by mass.

[0063] 2. Under nitrogen protection, polyethylene glycol was added to a reaction vessel. The mixture was refluxed and heated to 120°C. After melting by stirring, the reaction vessel was evacuated and dried for 30 minutes under the same conditions. Nitrogen gas was then introduced to restore atmospheric pressure. A 0.1 mol / L solution of stannous octoate toluene was added and stirred until homogeneous. L-lactide was added, and the mixture was stirred at 100 rpm for 10 minutes. The temperature was then raised to 130°C and reacted for 7 hours. The temperature was lowered to 80°C, and dichloromethane was added to dissolve the precipitate, yielding solution A. Solution A was then added dropwise to anhydrous diethyl ether at 0°C at a rate of 48 mL / min. The precipitate was collected by filtration and dried under vacuum to obtain polyethylene glycol-b-polylactic acid. The mass ratio of polyethylene glycol, stannous octoate toluene solution, L-lactide, and dichloromethane was 100:0.0081:205:66; the mass ratio of solution A to anhydrous diethyl ether was 1:10.

[0064] 3. Under nitrogen protection, 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1010 were added to a reactor. Stirring was started at 145 rpm, and the temperature was increased to 180°C at a rate of 2°C / min and held for 1.3 h. Then, the temperature was increased to 220°C at a rate of 1°C / min, and the reaction was continued until the water output reached more than 95% of the theoretical value. The pressure was reduced from atmospheric pressure to below 5 kPa within 30 min, and the reaction was continued for 1 h with the stirring rate increased to 220 rpm to obtain a bio-based polyester prepolymer. The mass ratio of 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant 1010 was 100:75:0.09:0.12.

[0065] 4. Under nitrogen protection, polyethylene glycol-b-polylactic acid (PEG-b-PLA) is added to a reactor and mixed with the bio-based polyester prepolymer. The mixture is stirred until homogeneous, and the temperature is maintained at 220°C. The reaction is carried out at atmospheric pressure for 30 minutes. Then, the pressure is reduced to below 100 Pa within 30 minutes, the temperature is raised to 240°C, and the reaction is maintained at this temperature for 2.5 hours. Nitrogen gas is introduced, and the atmospheric pressure is restored. The molten polymer is extruded, water-cooled, and sliced ​​to obtain modified bio-based polyester chips. The mass ratio of the bio-based polyester prepolymer to PEG-b-PLA is 1:2.

[0066] 5. Modified bio-based polyester chips and modified far-infrared composite particles are mixed evenly at a mass ratio of 30:9, added to a twin-screw extruder, melted and extruded at 235℃ to obtain functional masterbatch; modified bio-based polyester chips and functional masterbatch are mixed evenly at a mass ratio of 70:39 and melt-spun. The spinning temperature is set as follows: Zone 1: 220℃, Zone 2: 230℃, Zone 3: 240℃, and the spinneret temperature is 238℃. The spinneret cross-section shape is trilobal. The spun filaments are cooled by side blowing air at 23℃ and a wind speed of 0.7m / s, drawn at a draw ratio of 4, and drawn at a draw temperature of 90℃. After drawing, they are heat-set at 140℃ for 50s and wound to obtain highly hygroscopic and microcirculation-promoting vein care fibers.

[0067] Comparative Example 1

[0068] Comparative Example 1 provides a method for preparing a highly absorbent, microcirculation-promoting venous care fiber. The difference from Example 1 is that the far-infrared composite particles are not modified during the preparation process. The remaining steps are the same as in Example 1 and will not be repeated here.

[0069] Comparative Example 2

[0070] Comparative Example 2 provides a method for preparing highly absorbent and microcirculation-promoting venous care fibers. The difference from Example 1 is that the spinneret cross-section is circular. The remaining steps are the same as in Example 1 and will not be repeated here.

[0071] Comparative Example 3

[0072] Comparative Example 3 provides a method for preparing highly absorbent and microcirculation-promoting venous care fibers. Compared with Example 1, the difference is that polyethylene glycol-b-polylactic acid is not added during the bio-based polyester polycondensation stage, but instead is added during the melt spinning stage. The remaining steps are the same as in Example 1, and will not be repeated here.

[0073] To demonstrate the superior far-infrared heating and heat preservation performance of the embodiments of this application, the performance of the vein care fibers prepared in Examples 1-4 and Comparative Examples 1-3 was tested using the following test methods, and the test results are shown in Table 1.

[0074] Mechanical property testing: A yarn strength tester was used to test the maximum breaking force of the sample. The clamping length was 20cm. Each sample was tested ten times, and the average value was taken.

[0075] Far-infrared heating test: The fiber sample was woven into a plain weave fabric. In an environment with an ambient temperature of 25℃ and a humidity of 65%, the fabric was irradiated with a far-infrared lamp, and the temperature change on the surface of the fabric was detected.

[0076] Thermal insulation rate test: The fiber sample was woven into a plain weave fabric, and the thermal insulation performance of the fabric was tested using a flat plate thermal insulation tester. The plate temperature was set to 36℃ and the ambient temperature was 25℃.

[0077] Fiber moisture regain test: Clean the fiber sample with anhydrous ethanol to remove surface oil, and after drying, place the fiber sample in a constant temperature and humidity chamber at 20℃ and 75% humidity for 24 hours. Remove the fiber and weigh it to obtain the wet weight. Then, place the fiber sample in a 60℃ oven to dry for 2 hours, remove the fiber and weigh it to obtain the dry weight. Calculate the fiber moisture regain. Formula: (Wet weight - Dry weight) ÷ Dry weight × 100%.

[0078] Table 1. Performance test results of fibers prepared in Examples 1-4 and Comparative Examples 1-3

[0079]

[0080] As can be seen from Table 1, the highly absorbent and microcirculation-promoting venous care fibers prepared in Examples 1-4 are significantly superior to those in Comparative Examples 1-3 in terms of mechanical properties, far-infrared radiation heating performance, heat retention rate, and moisture regain. In Comparative Example 1, the far-infrared composite particles were not modified during preparation, resulting in poor dispersion and easy aggregation of the particles in the fiber matrix. This led to poor mechanical properties of the spun fibers and a decrease in their far-infrared heating performance, ultimately reducing the far-infrared radiation heating and heat retention rate of the fabric woven from them. In Comparative Example 2, a circular spinneret was used instead of a shaped spinneret during preparation, which resulted in poor hygroscopicity and reduced moisture regain of the fibers, thus affecting the overall heating and heat retention effects of the fabric. In Comparative Example 3, polyethylene glycol-b-polylactic acid was not added during the polycondensation of the bio-based polyester but instead added during melt spinning. This resulted in hydrophilic groups remaining free in the fiber matrix, which may lead to aggregation of hydrophilic groups, affecting the hygroscopicity of the fibers and causing a decrease in their heating effect. At the same time, the blended system could not grow the fiber molecular chains and may also affect its structural uniformity, resulting in a decrease in the mechanical properties of the fibers. In summary, the present application uses a bio-based polyester polycondensation process with the addition of polyethylene glycol-b-polylactic acid and in-situ grafting of hydrophilic groups, which effectively improves the fiber's moisture absorption durability, mechanical properties, and far-infrared heating performance, solving the problems of poor hydrophilic durability and reduced mechanical properties of existing far-infrared fibers.

[0081] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A highly absorbent fiber that promotes microcirculation in vein care, characterized in that, It includes modified bio-based polyester chips and modified far-infrared composite particles; the mass ratio of the modified bio-based polyester chips to the modified far-infrared composite particles is 100:(8-12). The modified bio-based polyester chips were prepared by introducing polyethylene glycol-b-polylactic acid during the synthesis of bio-based polyester using 2,5-furandicarboxylic acid and ethylene glycol as raw materials. The modified far-infrared composite particles are obtained by modifying the surface of far-infrared composite particles with silane.

2. The highly absorbent, microcirculation-promoting venous care fiber according to claim 1, characterized in that, The far-infrared composite particles are composed of nano-silica, nano-iron oxide, nano-alumina, nano-magnesium oxide, nano-potassium oxide, and nano-platinum powder.

3. The highly absorbent, microcirculation-promoting venous care fiber according to claim 2, characterized in that, The mass ratio of nano-silica, nano-iron oxide, nano-alumina, nano-magnesium oxide, nano-potassium oxide and nano-platinum powder is (45-65):(6-18):(12-18):(3-8):(5-8):(3-6).

4. The highly absorbent, microcirculation-promoting venous care fiber according to claim 1, characterized in that, The cross-sectional shape of the fiber can be any one of cross, star, or trefoil.

5. A method for preparing the highly absorbent, microcirculation-promoting venous care fiber as described in any one of claims 1-4, characterized in that, Includes the following steps: Modified far-infrared composite particles are obtained by modifying the far-infrared composite particles. Preparation of modified bio-based polyester chips; Modified bio-based polyester chips and modified far-infrared composite particles were mixed evenly and added to a melt spinning machine to prepare highly hygroscopic and microcirculation-promoting venous care fibers.

6. The method for preparing a highly absorbent, microcirculation-promoting venous care fiber according to claim 5, characterized in that, The specific steps for modifying the far-infrared composite particles are as follows: Add 2-3% KH-560 silane coupling agent (by mass of far-infrared composite particles) to a 95% ethanol aqueous solution. Adjust the pH to 4-5 with acetic acid and stir for 15-30 min. Then add 15% far-infrared composite particles (by mass of ethanol aqueous solution) and ultrasonically disperse at 300W power and 50-60℃ for 50-60 min to obtain a dispersion. Centrifuge the dispersion at 6000-8000 rpm for 10-15 min, collect the centrifuged precipitate, and wash the precipitate 2-4 times with anhydrous ethanol. Dry the precipitate at 70-80℃ for 4-6 h to obtain modified far-infrared composite particles.

7. The method for preparing a highly absorbent, microcirculation-promoting venous care fiber according to claim 5, characterized in that, The specific steps for preparing the modified bio-based polyester chips are as follows: Under nitrogen protection, polyethylene glycol was added to a reaction vessel, and the mixture was heated to 115-125°C under reflux conditions. After stirring and melting, the mixture was vacuum dried for 25-35 minutes. Nitrogen gas was then introduced to restore atmospheric pressure. A 0.1 mol / L solution of stannous octoate toluene was added and stirred until homogeneous. L-lactide was then added and stirred until homogeneous. The mixture was heated to 125-135°C and reacted for 5-7 hours. The temperature was then lowered to 78-82°C, and dichloromethane was added to dissolve the precipitate, yielding solution A. Solution A was then added dropwise to anhydrous diethyl ether at 0°C at a rate of 48-96 mL / min. The precipitate was collected by filtration and vacuum dried to obtain polyethylene glycol-b-polylactic acid. Under nitrogen protection, 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant were added to a reactor. Stirring was started at a rate of 140-150 rpm, and the temperature was increased to 175-185℃ at a rate of 2℃ / min. The temperature was maintained for 1-1.5 h, and then increased to 215-225℃ at a rate of 1℃ / min. The reaction was continued until the water output reached more than 95% of the theoretical value. The pressure was reduced to below 5 kPa within 25-35 min, and the reaction was continued for 0.8-1.2 h. The stirring rate was increased to 200-240 rpm to obtain a bio-based polyester prepolymer. Under nitrogen protection, polyethylene glycol-b-polylactic acid was added to a reactor and mixed with bio-based polyester prepolymer. The mixture was stirred until homogeneous and the temperature was maintained at 215-225℃. The reaction was carried out at atmospheric pressure for 25-35 minutes. Then, the pressure was reduced to below 100 Pa within 25-35 minutes, the temperature was raised to 235-245℃, and the reaction was maintained at this temperature for 2-3 hours. Nitrogen gas was introduced to restore atmospheric pressure. The molten polymer was extruded, water-cooled, and sliced ​​to obtain modified bio-based polyester chips.

8. The method for preparing a highly absorbent, microcirculation-promoting venous care fiber according to claim 7, characterized in that, The mass ratio of polyethylene glycol, stannous octanoate toluene solution, L-lactide, and dichloromethane is 100:(0.008-0.0082):(190-210):(65-67); the mass ratio of solution A and anhydrous diethyl ether is 1:10; the mass ratio of 2,5-furandicarboxylic acid, ethylene glycol, tetrabutyl titanate, and antioxidant is 100:(74-76):(0.08-0.1):(0.11-0.13); and the mass ratio of bio-based polyester prepolymer and polyethylene glycol-b-polylactic acid is 1:(1.9-2.1).

9. The method for preparing a highly absorbent, microcirculation-promoting venous care fiber according to claim 7, characterized in that, The antioxidant is any one of antioxidant 1010, antioxidant 1076 and antioxidant 1098.

10. The method for preparing a highly absorbent, microcirculation-promoting venous care fiber according to claim 5, characterized in that, The specific steps for preparing the highly absorbent, microcirculation-promoting venous care fiber are as follows: Modified bio-based polyester chips and modified far-infrared composite particles were mixed evenly at a mass ratio of 30:(8-12), added to a twin-screw extruder, melted and extruded at 230-240℃ to obtain functional masterbatch. Modified bio-based polyester chips and functional masterbatch were mixed evenly at a mass ratio of 70:(38-42) and then melt-spun. The spinning temperature was set as follows: Zone 1: 215-225℃, Zone 2: 225-235℃, Zone 3: 235-245℃, and the spinneret temperature was 235-240℃. The spun filaments were cooled by side blowing at 20-25℃ and a wind speed of 0.6-0.8m / s, and then drawn at a draw ratio of 3.8-4.5 at a draw temperature of 85-95℃. After drawing, the filaments were heat-set at 130-150℃ for 40-60s and then wound to obtain highly hygroscopic and microcirculation-promoting venous care fibers.

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