Preparation method of polyester fiber with health-care function

Abstract

The invention relates to the technical field of chemical fibers, and discloses a preparation method of a health-care functional polyester fiber, which comprises the following steps: (1) modifying bamboo charcoal powder and tourmaline powder by using an amino silane coupling agent to prepare modified negative ion powder; (2) modifying the silicon carbide powder and the silicon nitride powder with hydroxyl polyethylene glycol epoxy ether to prepare modified far infrared powder; (3) adding the modified negative ion powder and the modified far infrared powder into ethylene glycol to prepare a composite functional alcoholic solution; (4) carrying out esterification reaction on terephthalic acid, ethylene glycol and 1, 5-pentanediol to prepare an esterification product; (5) adding the composite functional alcohol solution, 2, 6-naphthalic acid and a catalyst, and carrying out condensation polymerization to prepare polyester; and (6) carrying out melt spinning. According to the invention, the dispersity and interfacial compatibility of the functional powder can be fundamentally improved, and firm combination is realized, so that the health-care fiber with far infrared radiation, negative ion release and excellent mechanical properties is prepared.

Description

Technical Field

[0001] This invention belongs to the technical field of chemical fibers, and more specifically relates to a method for preparing health-functional polyester fibers. Background Technology

[0002] With increasing health awareness, the demand for textiles has shifted from traditional basic functions such as warmth and coverage to high-tech functional products that integrate health benefits and comfort. Negative ions are known for their air-purifying, fatigue-relieving, and sleep-improving effects, while far-infrared rays resonate with human cells, promoting microcirculation and increasing perceived body temperature, resulting in significant warmth and therapeutic benefits. Therefore, health-functional fibers that release negative ions and radiate far-infrared rays are highly favored by the market.

[0003] Currently, the mainstream technology for preparing such functional fibers involves introducing inorganic powders with corresponding functions into polymer matrices such as polyester (PET) through blending, followed by spinning. However, this method suffers from the following problems that severely restrict the performance of fiber products:

[0004] First, inorganic powders have poor compatibility and dispersibility with organic polymer matrices. Functional powders are mostly hydrophilic inorganic oxides or ceramic materials, which are incompatible with the hydrophobic polyester molecular chains and are prone to agglomeration. Simple mechanical stirring and conventional silane coupling agent treatment are insufficient to achieve nanoscale, long-term stable dispersion of powders in the polymerization system. These micron-sized or even larger agglomerates become fatal defects during spinning, severely damaging the continuity and density of fibers, leading to a sharp decline in mechanical properties (strength, elongation), and problems such as fuzzing and breakage. Furthermore, the functional powders encased inside the agglomerates cannot come into contact with the external environment, resulting in a significant reduction in their health benefits.

[0005] Second, the interfacial bonding between functional powder and the matrix is ​​weak. Existing technologies mostly rely on physical coating or weak van der Waals forces to "wrap" the powder in the polymer. This weak interfacial bonding makes it very easy for functional powder to migrate from the inside of the fiber to the surface and fall off during subsequent high-temperature spinning, stretching and daily use and washing. As a result, the product has poor functional durability. After several washes, the negative ion release and far-infrared emissivity of the product will significantly decrease, and the lifespan is short, which cannot meet the market's requirements for durable consumer goods.

[0006] Third, functionality and mechanical properties are difficult to coordinate. In order to pursue higher functional performance, a large amount of functional powder is often required, but this will further aggravate powder agglomeration and interface problems, resulting in poor fiber spinnability and loss of mechanical strength, making it difficult to achieve both excellent health care functions and mechanical properties close to those of ordinary fibers. Summary of the Invention

[0007] The main objective of this invention is to address the aforementioned problems by providing a method for preparing health-functional polyester fibers. This method can fundamentally improve the dispersibility and interfacial compatibility of functional powders and achieve a strong bond between functional components and the polyester matrix, thereby developing high-quality health-functional fibers that simultaneously possess excellent and long-lasting far-infrared radiation, negative ion release functions, and superior mechanical properties.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0009] A method for preparing a health-functional polyester fiber includes the following steps:

[0010] (1) Bamboo charcoal powder, tourmaline powder, aminosilane coupling agent and water are mixed, ball-milled and dried to obtain modified negative ion powder;

[0011] (2) After acid treatment of silicon carbide powder and silicon nitride powder, the acid-treated powder is dispersed in toluene, hydroxyl polyethylene glycol epoxy ether and triethylamine are added, and after reflux reaction, the powder is centrifuged, washed and dried to obtain modified far-infrared powder.

[0012] (3) The modified negative ion powder and the modified far-infrared powder were added to ethylene glycol and ultrasonically dispersed to prepare a composite functional alcohol solution;

[0013] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol are fed in an alcohol-acid molar ratio of 1.4 to 1.6:1, and then an esterification reaction is carried out to obtain the esterified product;

[0014] (5) The esterification product is first cooled to below 200°C, and then a composite functional alcohol solution, 2,6-naphthalenedicarboxylic acid and catalyst are added. The ethylene glycol solvent is first removed under vacuum, and then polycondensation reaction is carried out to obtain polyester.

[0015] (6) Polyester is melt-spun to obtain polyester fiber.

[0016] More preferably, in step (1), the mass ratio of bamboo charcoal powder to tourmaline powder is 1:1~2; the particle size of bamboo charcoal powder and tourmaline powder does not exceed 10μm; the amount of aminosilane coupling agent is 1~3% of the total mass of bamboo charcoal powder and tourmaline powder; the amount of water is 10~20% of the total mass of bamboo charcoal powder and tourmaline powder; and the aminosilane coupling agent is KH-550, KH792 or KH602.

[0017] More preferably, in step (2), the mass ratio of silicon carbide powder to silicon nitride powder is 1~2:1; the particle size of silicon carbide powder and silicon nitride powder does not exceed 1μm; the acid treatment includes: immersing the powder in a nitric acid solution with a mass concentration of 8~10%, stirring at 50~60℃ for 1~2h, and then filtering, washing and drying.

[0018] More preferably, in step (2), the amount of hydroxyl polyethylene glycol epoxy ether used is 5-8% of the mass of the acid-treated powder; the average molecular weight of the hydroxyl polyethylene glycol epoxy ether is 400-600; the ratio of the acid-treated powder to toluene is 1g:15-20mL; the amount of triethylamine used is 0.02-0.06% of the mass of the acid-treated powder; and the reflux reaction time is 4-5h.

[0019] More preferably, in step (3), the mass concentration of modified negative ion powder and modified far-infrared powder in the composite functional alcohol solution is 15~20%, and the mass ratio of modified negative ion powder and modified far-infrared powder is 1:1.

[0020] More preferably, in step (4), the conditions for the esterification reaction are: temperature 243~248℃, time 1~5h; the molar percentage of 1,5-pentanediol in the total alcohol (ethylene glycol and 1,5-pentanediol) is 10~20%.

[0021] More preferably, in step (5), the amount of 2,6-naphthalenedicarboxylic acid is 1-2% of the mass of terephthalic acid; the amount of the composite functional alcohol solution is 25-30% of the mass of terephthalic acid; and the pressure of vacuum removal is less than 5 kPa.

[0022] More preferably, in step (5), the conditions for the polycondensation reaction are: temperature 285~290℃, absolute pressure ≤300Pa, time 1~3h; the catalyst is an antimony-based, germanium-based, titanium-based, aluminum-based or cobalt-based catalyst, and the amount of catalyst is 1-5‰ of the mass of terephthalic acid.

[0023] More preferably, in step (5), the intrinsic viscosity of the polyester is between 0.645 and 0.655 dL / g.

[0024] More preferably, in step (6), the temperature of the melt spinning is 283~293℃.

[0025] In a further preferred embodiment, in step (6), the filaments obtained after melt spinning are sequentially cooled by ring blowing, oiled, stretched, shaped, and wound to obtain polyester fibers.

[0026] More preferably, the air pressure of the ring-blowing cooling is controlled at 24~28 Pa, and the air temperature is controlled at 22~24℃; the bundling position is 810~870 mm below the spinneret; the oiling rate is 0.60~0.80%; the stretching is performed by stretching through a first hot roller and a second hot roller, the temperature of the first hot roller is 88~91℃ and the speed is 1470~1520 m / min, and the temperature of the second hot roller is 125~133℃ and the speed is 3700~3900 m / min.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) Bamboo charcoal powder and tourmaline powder with negative ion release function are rich in hydroxyl groups and can react effectively with aminosilane coupling agent to obtain modified negative ion powder; silicon nitride ceramic powder and silicon carbide ceramic powder with far-infrared radiation function are first treated with acid to increase the surface hydroxyl density, and then reacted with hydroxyl polyethylene glycol epoxy ether (HO-PEG-Epoxide) to introduce flexible PEG long chain with hydroxyl end into the powder surface to obtain modified far-infrared powder;

[0029] (2) After modification, negative ion powder and far-infrared powder can improve their compatibility and dispersibility in ethylene glycol, which is conducive to introducing the powder into the polyester macromolecular chain. In particular, the PEG segments on the modified far-infrared powder can improve the toughness of polyester fibers and improve the brittleness caused by the addition of powder.

[0030] (3) In addition, the co-esterification of terephthalic acid, ethylene glycol and 1,5-pentanediol is also to introduce the long flexible chain segment formed by 1,5-pentanediol in advance to improve the brittleness caused by the addition of powder; while the subsequent addition of 2,6-naphthalenedicarboxylic acid compensates for the strength loss caused by the introduction of powder and 1,5-pentanediol by utilizing its rigid structure. Overall, the influence of flexible chain segment, rigid chain segment and powder on the fiber mechanical properties is balanced by the type and ratio of alkyd monomers and the proportion of modified powder, thereby improving the quality of the final polyester fiber.

[0031] (4) By modifying the negative ion powder and far-infrared powder, they can be introduced into the polyester molecular chain through chemical grafting, ensuring the durability of the negative ion performance and far-infrared performance of the polyester fiber, and without damaging the original mechanical properties of the polyester fiber, thereby greatly expanding its application fields. Detailed Implementation

[0032] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0033] Example 1

[0034] (1) Bamboo charcoal powder and tourmaline powder are mixed in a mass ratio of 1:1 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 2% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0035] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 1:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 7% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 600) and 0.05% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0036] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0037] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.6:1, with 1,5-pentanediol accounting for 16% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 247°C for 3 hours to obtain the esterified product.

[0038] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 20% of the mass of terephthalic acid, 2,6-naphthalenedicarboxylic acid accounting for 1.5% of the mass of terephthalic acid, and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 285°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0039] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 284℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0040] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 28 Pa and the air temperature controlled at 23 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.66%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 89 °C and the speed is 1475 m / min. The temperature of the second hot roller is 129 °C and the speed is 3850 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0041] Example 2

[0042] (1) Bamboo charcoal powder and tourmaline powder are mixed in a mass ratio of 1:1 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 3% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0043] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 2:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 5% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 600) and 0.03% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0044] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0045] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.6:1, with 1,5-pentanediol accounting for 20% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 245°C for 3 hours to obtain the esterified product.

[0046] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 25% of the mass of terephthalic acid, 2,6-naphthalenedicarboxylic acid accounting for 2% of the mass of terephthalic acid, and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 287°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0047] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 285℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 293℃; the polyester is melt spun.

[0048] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 27 Pa and the air temperature controlled at 22 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.67%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 90 °C and the speed is 1500 m / min. The temperature of the second hot roller is 127 °C and the speed is 3750 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0049] Example 3

[0050] (1) Bamboo charcoal powder and tourmaline powder are mixed at a mass ratio of 1:2 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 3% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0051] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 2:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 7% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 600) and 0.05% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0052] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0053] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.5:1, with 1,5-pentanediol accounting for 16% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 247°C for 3 hours to obtain the esterified product.

[0054] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 30% of the mass of terephthalic acid, 2,6-naphthalenedicarboxylic acid accounting for 2% of the mass of terephthalic acid, and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 285°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0055] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 284℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0056] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 26 Pa and the air temperature controlled at 22 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.63%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 90 °C and the speed is 1470 m / min. The temperature of the second hot roller is 132 °C and the speed is 3850 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0057] Example 4

[0058] (1) Bamboo charcoal powder and tourmaline powder are mixed at a mass ratio of 1:2 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 3% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0059] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 1:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add hydroxyl polyethylene glycol epoxy ether (average molecular weight of 400) accounting for 8% of the mass of the acid-treated powder and triethylamine accounting for 0.06% of the mass of the acid-treated powder, reflux for 5 h, centrifuge, wash and dry to obtain modified far-infrared powder;

[0060] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0061] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.4:1, with 1,5-pentanediol accounting for 15% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 247°C for 3 hours to obtain the esterified product.

[0062] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 30% of the mass of terephthalic acid, 2,6-naphthalenedicarboxylic acid accounting for 2% of the mass of terephthalic acid, and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 2 kPa, and then the temperature is raised to 287°C and the absolute pressure is 150 Pa to carry out a polycondensation reaction for 2.5 h to obtain polyester.

[0063] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 286℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0064] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 24 Pa and the air temperature controlled at 24 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.68%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 88 °C and the speed is 1475 m / min. The temperature of the second hot roller is 129 °C and the speed is 3800 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0065] Comparative Example 1

[0066] In this comparative example, too much 1,5-pentanediol was added during the polyester preparation process; the remaining steps and the polyester fiber preparation process were the same as in Example 1.

[0067] (1) Bamboo charcoal powder and tourmaline powder are mixed in a mass ratio of 1:1 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 2% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0068] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 1:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 7% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 600) and 0.05% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0069] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0070] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.6:1, with 1,5-pentanediol accounting for 25% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 247°C for 3 hours to obtain the esterified product.

[0071] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 20% of the mass of terephthalic acid, 2,6-naphthalenedicarboxylic acid accounting for 1.5% of the mass of terephthalic acid, and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 285°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0072] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 284℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0073] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 28 Pa and the air temperature controlled at 23 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.66%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 89 °C and the speed is 1475 m / min. The temperature of the second hot roller is 129 °C and the speed is 3850 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0074] Comparative Example 2

[0075] In this comparative example, 2,6-naphthalenedicarboxylic acid was not added during the polyester preparation process, and the remaining steps and the polyester fiber preparation process were the same as in Example 1.

[0076] (1) Bamboo charcoal powder and tourmaline powder are mixed in a mass ratio of 1:1 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 2% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0077] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 1:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 7% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 600) and 0.05% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0078] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0079] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.6:1, with 1,5-pentanediol accounting for 16% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 247°C for 3 hours to obtain the esterified product.

[0080] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 20% of the mass of terephthalic acid and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 285°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0081] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 284℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0082] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 28 Pa and the air temperature controlled at 23 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.66%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 89 °C and the speed is 1475 m / min. The temperature of the second hot roller is 129 °C and the speed is 3850 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0083] Comparative Example 3

[0084] In this comparative example, the polyester preparation process involved 2,6-naphthalenedicarboxylic acid during the esterification stage, while the remaining steps and the polyester fiber preparation process were the same as in Example 1.

[0085] (1) Bamboo charcoal powder and tourmaline powder are mixed in a mass ratio of 1:1 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 2% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0086] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 1:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 7% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 600) and 0.05% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0087] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0088] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.6:1, with 1,5-pentanediol accounting for 16% of the total alcohol. Then, 2,6-naphthalenedicarboxylic acid, accounting for 1.5% of the mass of terephthalic acid, was added. The esterification reaction was then carried out at 247°C for 3 hours to obtain the esterified product.

[0089] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 20% of the mass of terephthalic acid and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 285°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0090] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 284℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0091] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 28 Pa and the air temperature controlled at 23 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.66%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 89 °C and the speed is 1475 m / min. The temperature of the second hot roller is 129 °C and the speed is 3850 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0092] Comparative Example 4

[0093] In this comparative example, the molecular weight of the hydroxyl polyethylene glycol epoxy ether added during the polyester preparation process was too large. The remaining steps and the polyester fiber preparation process were the same as in Example 1.

[0094] (1) Bamboo charcoal powder and tourmaline powder are mixed in a mass ratio of 1:1 to obtain mixed powder I; the mixed powder, aminosilane coupling agent KH-550 accounting for 2% of the mass of mixed powder I, and water accounting for 15% of the mass of mixed powder I are mixed and ball-milled at 500 rpm for 3 hours, and then dried to obtain modified negative ion powder;

[0095] (2) Mix silicon carbide powder and silicon nitride powder at a mass ratio of 1:1 to obtain mixed powder II; immerse mixed powder II in nitric acid solution with a mass concentration of 8% and stir at 60°C for 1.5 h, then filter, wash and dry; disperse the acid-treated powder in toluene at a ratio of 1 g: 20 mL, then add 7% hydroxyl polyethylene glycol epoxy ether (average molecular weight of 1000) and 0.05% triethylamine, and reflux for 5 h, then centrifuge, wash and dry to obtain modified far-infrared powder;

[0096] (3) Modified negative ion powder and modified far-infrared powder were added to ethylene glycol at a mass ratio of 1:1 and ultrasonically dispersed to obtain a composite functional alcohol solution with a modified powder mass concentration of 20%.

[0097] (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol were fed in an alcohol-acid molar ratio of 1.6:1, with 1,5-pentanediol accounting for 16% of the total alcohol molar percentage. Then, an esterification reaction was carried out at 247°C for 3 hours to obtain the esterified product.

[0098] (5) The esterification product is first cooled to below 200°C, and a composite functional alcohol solution accounting for 20% of the mass of terephthalic acid, 2,6-naphthalenedicarboxylic acid accounting for 1.5% of the mass of terephthalic acid, and antimony trioxide accounting for 4‰ of the mass of terephthalic acid are added. The ethylene glycol solvent is first removed under a pressure of 3 kPa, and then the temperature is raised to 285°C and a polycondensation reaction is carried out under an absolute pressure of 200 Pa for 2 hours to obtain polyester.

[0099] (6) The melt is transported through the melt delivery pump in the melt pipeline, and the delivery temperature is controlled at 284℃; the melt is transported to the spinning box through the melt filter, melt booster pump and melt cooler, and then metered by the metering pump before being sent to the spinning assembly for spinning. The spinneret used is a circular spinneret with 72 holes, and the spinning temperature is controlled at 292℃; the polyester is melt spun.

[0100] (7) The filaments obtained after melt spinning are cooled by ring blowing, with the air pressure controlled at 28 Pa and the air temperature controlled at 23 °C. The bundle is located 820 mm below the spinneret, and the oiling rate is 0.66%. Then, the filaments are stretched by the first hot roller and the second hot roller. The temperature of the first hot roller is 89 °C and the speed is 1475 m / min. The temperature of the second hot roller is 129 °C and the speed is 3850 m / min. After that, the filaments are shaped and wound to obtain polyester fibers.

[0101] Table 1 Performance test data of polyester fibers

[0102] Functional indicators Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Initial modulus (cN / dtex) 69 78 81 72 50 57 72 54 Fracture strength (cN / dtex) 3.65 3.61 3.56 3.64 2.87 3.29 3.42 2.96 Elongation at break (%) 20.4 23.6 25.1 21.8 21.6 22.8 18.1 16.5 Far-infrared emissivity (%) 0.78 0.84 0.86 0.89 0.77 0.82 0.71 0.66 <![CDATA[Negative ion release amount (number / cm 3 )]]> 514 629 796 735 529 543 482 501

[0103] As shown in Table 1, in Comparative Example 1, the excessive addition of 1,5-pentanediol during polyester preparation resulted in a higher number of flexible molecular chains, leading to a decrease in polyester fiber strength. Similarly, in Comparative Example 2, the absence of 2,6-naphthalenedicarboxylic acid as a rigid segment during polyester preparation also resulted in a decrease in polyester fiber strength and modulus. In Comparative Example 3, the addition of 2,6-naphthalenedicarboxylic acid during the esterification stage resulted in an esterification product with a molecular chain structure that was not conducive to the effective introduction of modified powders (especially modified far-infrared powders). Consequently, the mechanical properties of the resulting polyester were not ideal, with fiber strength and elongation inferior to those of Example 1. In Comparative Example 4, the excessively large molecular weight of the added hydroxyl polyethylene glycol epoxy ether led to excessively long molecular chains, which easily resulted in the burial of terminal hydroxyl groups. This reduced the efficiency of grafting modified far-infrared powders onto the polyester molecular chains. Furthermore, the excessively long flexible chains reduced the crystallinity and crystalline integrity of the polyester, leading to a decrease in the final fiber strength and modulus.

[0104] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a health-functional polyester fiber, characterized in that, Includes the following steps: (1) Bamboo charcoal powder, tourmaline powder, aminosilane coupling agent and water are mixed, ball-milled and dried to obtain modified negative ion powder; (2) After acid treatment of silicon carbide powder and silicon nitride powder, the acid-treated powder is dispersed in toluene, hydroxyl polyethylene glycol epoxy ether and triethylamine are added, and after reflux reaction, the powder is centrifuged, washed and dried to obtain modified far-infrared powder. (3) The modified negative ion powder and the modified far-infrared powder were added to ethylene glycol and ultrasonically dispersed to prepare a composite functional alcohol solution; (4) Terephthalic acid, ethylene glycol and 1,5-pentanediol are fed in an alcohol-acid molar ratio of 1.4 to 1.6:1, and then an esterification reaction is carried out to obtain the esterified product; (5) The esterification product is first cooled to below 200°C, and then a composite functional alcohol solution, 2,6-naphthalenedicarboxylic acid and catalyst are added. The ethylene glycol solvent is first removed under vacuum, and then polycondensation reaction is carried out to obtain polyester. (6) Polyester is melt-spun to obtain polyester fiber.

2. The method for preparing health-functional polyester fiber as described in claim 1, characterized in that, In step (1), the mass ratio of bamboo charcoal powder to tourmaline powder is 1:1~2; the amount of aminosilane coupling agent is 1~3% of the total mass of bamboo charcoal powder and tourmaline powder; the amount of water is 10~20% of the total mass of bamboo charcoal powder and tourmaline powder; and the aminosilane coupling agent is KH-550, KH792 or KH602.

3. The method for preparing health-functional polyester fiber as described in claim 1, characterized in that, In step (2), the mass ratio of silicon carbide powder to silicon nitride powder is 1~2:1; the acid treatment includes: immersing the powder in a nitric acid solution with a mass concentration of 8~10%, stirring at 50~60℃ for 1~2 hours, and then filtering, washing and drying.

4. The method for preparing health-functional polyester fiber as described in claim 1 or 3, characterized in that, In step (2), the amount of hydroxyl polyethylene glycol epoxy ether used is 5-8% of the mass of the acid-treated powder; the average molecular weight of the hydroxyl polyethylene glycol epoxy ether is 400-600; the ratio of the acid-treated powder to toluene is 1g:15-20mL; the amount of triethylamine used is 0.02-0.06% of the mass of the acid-treated powder; and the reflux reaction time is 4-5h.

5. The method for preparing health-functional polyester fiber as described in claim 1, characterized in that, In step (3), the mass concentration of modified negative ion powder and modified far-infrared powder in the composite functional alcohol solution is 15~20%, and the mass ratio of modified negative ion powder and modified far-infrared powder is 1:

1.

6. The method for preparing the health-functional polyester fiber as described in claim 1, characterized in that, In step (4), the esterification reaction conditions are: temperature 243~248℃, time 1~5h; the 1,5-pentanediol accounts for 10~20% of the total alcohol.

7. The method for preparing health-functional polyester fiber as described in claim 1, 5, or 6, characterized in that, In step (5), the amount of 2,6-naphthalenedicarboxylic acid used is 1-2% of the mass of terephthalic acid; the amount of the composite functional alcohol solution used is 25-30% of the mass of terephthalic acid; and the pressure of vacuum removal is less than 5 kPa.

8. The method for preparing the health-functional polyester fiber as described in claim 1, characterized in that, In step (5), the conditions for the polycondensation reaction are: temperature 285~290℃, absolute pressure ≤300Pa, time 1~3h; the catalyst is an antimony-based, germanium-based, titanium-based, aluminum-based or cobalt-based catalyst, and the amount of catalyst is 1-5‰ of the mass of terephthalic acid.

9. The method for preparing health-functional polyester fiber as described in claim 1, 5, or 6, characterized in that, In step (6), the temperature of the melt spinning is 283~293℃.

10. The method for preparing the health-functional polyester fiber as described in claim 1 or 9, characterized in that, In step (6), the filaments obtained after melt spinning are successively cooled by ring blowing, oiled, stretched, shaped and wound to obtain polyester fibers.