Cooling polyamide fiber and method for producing the same

Abstract

The application provides a cool polyamide fiber and a preparation method thereof, and relates to the technical field of fiber materials. The preparation method of the cool polyamide fiber is as follows: 96-100 parts of polyamide 56 chips, 2-3 parts of surface-treated jade powder and 5-6 parts of a phosphine sapphyrin silicon-containing flame retardant are mixed at high speed, extruded and granulated to prepare polyamide master batches; the polyamide master batches are melt-spun to prepare polyamide fibers; the polyamide fibers are sequentially finished with an aqueous formaldehyde solution and proto-catechuic acid, and then washed, dried and cooled to prepare the cool polyamide fiber. The cool polyamide fiber provided in the application has the functions of coolness, bacteriostasis and flame retardation.

Description

Technical Field

[0001] This invention relates to the field of fiber materials technology, specifically to a cool-feeling polyamide fiber and its preparation method. Background Technology

[0002] Currently, most polyamide fibers still rely on petroleum products for their raw materials. To reduce this over-reliance, the use of bio-based resources to replace petrochemical raw materials is imperative. Bio-based polyamide 56 (PA56) is a novel polyamide material polymerized from bio-based pentanediamine and adipic acid, where pentanediamine can be prepared by fermentation of starch and other materials. Compared to widely used nylon 66 and nylon 6 (PA6) fibers, its bio-based content can reach over 40%, effectively reducing dependence on petrochemical raw materials and aligning with the concept of green and sustainable development.

[0003] With the improvement of living standards and the change of consumption concepts, people's demand for comfortable and functional textiles has increased significantly. Especially in the hot summer, when human skin comes into direct contact with clothing, sweat adheres to the loose and porous clothing, which can cause a sticky feeling and easily breed bacteria. Therefore, cool and comfortable clothes have become a necessity in the hot summer.

[0004] Furthermore, the literature "Isothermal Crystallization Behavior and Tensile Properties of Flame-Retardant PA56 Composites" points out that the combustion performance of PA56 is similar to that of PA6, with an LOI value of approximately 20% to 22%, and it can only pass the V-2 level in the UL94 vertical burning test. The flame retardant properties of fiber fabrics woven from pure PA56 fibers are poor. According to patent CN 119932920 B, the limiting oxygen index of PA56 fabrics without flame retardant treatment is only 20.9%, and its combustion performance is difficult to meet people's safety requirements for fabrics.

[0005] Based on the above problems, this application provides a polyamide fiber that integrates antibacterial, flame retardant and cooling properties. Summary of the Invention

[0006] The purpose of this invention is to provide a cooling polyamide fiber and its preparation method to solve the problems existing in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A cooling polyamide fiber is prepared by mixing 96-100 parts of polyamide 56 chips, 2-3 parts of surface-treated jade powder, and 5-6 parts of a phosphorus-containing silicon flame retardant at high speed, and extruding and granulating to obtain a polyamide masterbatch; melting and spinning the polyamide masterbatch to obtain a polyamide fiber; and then treating the polyamide fiber with formaldehyde aqueous solution and protocatechuic acid in sequence, followed by washing and drying to obtain the cooling polyamide fiber.

[0008] Furthermore, the surface-treated jade powder is prepared by treating jade powder with γ-aminopropyltrimethoxysilane.

[0009] Furthermore, the phosphaphenanthrene-based silicon-containing flame retardant is prepared by reacting phenyltrichlorosilane and 2-hydroxyethyl acrylate to obtain an intermediate; and then reacting the intermediate with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide.

[0010] Furthermore, the reaction mechanism for obtaining the intermediate from the reaction of phenyltrichlorosilane and 2-hydroxyethyl acrylate is as follows:

[0011] Furthermore, the reaction mechanism of the intermediate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide, to obtain phosphaphenanthrene-based silicon-containing flame retardants is as follows:

[0012] A method for preparing a cooling polyamide fiber includes the following preparation steps: (1) Weigh the intermediate and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide at a molar ratio of 1:3; mix the intermediate and dioxane at a mass ratio of 1:(4~6) to prepare a reaction solution; mix 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide, triethylamine and dioxane at a mass ratio of 1:(0.02~0.03):(4~6), heat to 40~50℃, add the reaction solution dropwise at a uniform rate within 40 min, and after the dropwise addition is completed, heat to 70~80℃, continue stirring and reacting for 10~15 h, evaporate under reduced pressure, wash with deionized water, and dry under vacuum at 50~60℃ to obtain a phosphaphenanthrene-based silicon-containing flame retardant; (2) Weigh jade powder and γ-aminopropyltrimethoxysilane at a mass ratio of 1:(0.06~0.08); mix γ-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water at a mass ratio of 1:(20~30):(10~14) to prepare a silane solution; mix jade powder and anhydrous ethanol at a mass ratio of 1:(20~30), adjust the pH to 4~5 with formic acid, stir at 50~60℃ for 25~35min, add the silane solution, heat to 60~70℃ and stir for 2~3h, filter, wash with anhydrous ethanol, and vacuum dry at 70~80℃ to obtain surface-treated jade powder; (3) By weight, there are 96-100 parts of polyamide 56 chips, 2-3 parts of surface-treated jade powder, and 5-6 parts of phosphanium-phenanthroline silicon-containing flame retardant; the polyamide 56 chips, surface-treated jade powder, and phosphanium-phenanthroline silicon-containing flame retardant are mixed at high speed in a high-speed mixer, and then extruded and granulated in a screw extruder to obtain polyamide masterbatch; the polyamide masterbatch is melt-spun in a spinning machine to obtain polyamide fiber; (4) Place the polyamide fiber in a formaldehyde aqueous solution with a bath ratio of 1:(20~30), stir at 85~95℃ for 60~80min under nitrogen protection, remove it, wash it with deionized water, dry it at 60~70℃ for 1~2h, then place it in a finishing solution with a bath ratio of 1:(20~30), stir at 80~90℃ for 1~2h under nitrogen protection, raise the temperature to 100~110℃, continue stirring for 70~80min, remove it, wash it with hot water at 80~90℃, and dry it at 60~70℃ to obtain cool-feeling polyamide fiber.

[0013] Furthermore, the preparation process of the intermediate in step (1) is as follows: phenyltrichlorosilane, triethylamine, and 2-hydroxyethyl acrylate are weighed in a molar ratio of 1:3:(3.1~3.2); 2-hydroxyethyl acrylate and triethylamine are dissolved in acetonitrile in 6~8 times the mass of 2-hydroxyethyl acrylate, stirred at room temperature for 10~20 min, heated to 50~60℃, and phenyltrichlorosilane is added at a uniform rate within 1 h. After the addition is complete, the reaction is continued to be stirred for 5~6 h, filtered, and the filtrate is evaporated under reduced pressure to obtain the intermediate.

[0014] Furthermore, the jade powder in step (2) has a particle size of 400~600nm and is produced by Xiamen Luyi Color Masterbatch Co., Ltd.

[0015] Furthermore, the polyamide 56 chips described in step (3) have a viscosity of 172.2 mL / g and are produced by Shanghai Kaisai Biotechnology R&D Center Co., Ltd.

[0016] Furthermore, in step (3), the high-speed mixing speed is 800~1400 r / min and the mixing time is 10~15 min.

[0017] Furthermore, the extrusion temperature of the extrusion granulation in step (3) is 260~270℃, and the screw speed is 50~60r / min.

[0018] Furthermore, the formaldehyde aqueous solution in step (4) has a mass fraction of 36%.

[0019] Furthermore, the preparation process of the finishing solution in step (4) is as follows: protocatechuic acid, p-toluenesulfonic acid monohydrate, and N,N-dimethylformamide are mixed evenly in a mass ratio of 1:(0.003~0.005):(20~22) to prepare the finishing solution.

[0020] The beneficial effects of this invention are: Effect 1: An intermediate is prepared by reacting phenyltrichlorosilane and 2-hydroxyethyl acrylate; the carbon-carbon double bond on the intermediate is added to the pH bond on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide to prepare a phosphaphenanthrene-based silicon-containing flame retardant; the phosphaphenanthrene-based silicon-containing flame retardant contains multiple elements such as phosphorus, sulfur and silicon, which can form a synergistic flame retardant system and endow polyamide fibers with excellent flame retardant ability.

[0021] Effect 2: Surface-treated jade powder is prepared by treating jade powder with γ-aminopropyltrimethoxysilane. Jade and other minerals have high thermal conductivity. Grinding them into micro-nano powder and adding them to fibers significantly improves the overall thermal conductivity of the fibers. When this jade powder-containing fiber comes into contact with warm skin, its excellent thermal conductivity allows it to quickly conduct heat away from the skin surface, causing the temperature of the contact area to drop instantly, effectively improving the coolness and comfort of wearing the garment. Surface treatment of jade powder with a silane coupling agent can effectively reduce the surface energy of the powder and reduce the agglomeration of the jade powder.

[0022] Effect 3: Polyamide fibers are treated with formaldehyde aqueous solution to hydroxymethylate the surface of the polyamide fibers, and then esterified with the carboxylic acid groups on protocatechuic acid to graft protocatechuic acid onto the surface of the polyamide fibers. Protocatechuic acid is a naturally occurring phenolic acid that can destroy the physical structure of bacteria and interfere with their physiological metabolism, and has a wide range of antibacterial activities. Grafting protocatechuic acid onto the surface of polyamide fibers enhances the antibacterial ability of the polyamide fibers. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] In the following examples and comparative examples, the process parameters for melt spinning are as follows: screw temperature is 275℃ in zone I, 288℃ in zone II, 283℃ in zone III, and 283℃ in zone IV; spinning speed is 600m / min; draw ratio is 3.5 times; and spinneret specifications are 0.3mm×36f. Example 1:

[0025] This embodiment provides a method for preparing cool-feeling polyamide fibers, including the following preparation steps: (1) Weigh phenyltrichlorosilane, triethylamine, and 2-hydroxyethyl acrylate in a molar ratio of 1:3:3.1; dissolve 2-hydroxyethyl acrylate and triethylamine in acetonitrile in 6 times the mass of 2-hydroxyethyl acrylate, stir at room temperature for 10 min, heat to 50 °C, add phenyltrichlorosilane at a uniform rate over 1 h, continue stirring for 6 h after the addition is complete, filter, and evaporate the filtrate under reduced pressure to obtain the intermediate; weigh the intermediate and 9,10-dihydro-9-oxa-10 in a molar ratio of 1:3:3.1. -phosphaphenanthrene-10-sulfide; the intermediate and dioxane were mixed in a mass ratio of 1:4 to prepare a reaction solution; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide, triethylamine and dioxane were mixed in a mass ratio of 1:0.02:4, heated to 40℃, and the reaction solution was added dropwise at a uniform rate over 40 min. After the addition was completed, the temperature was raised to 70℃, and the reaction was continued with stirring for 15 h. The mixture was then evaporated under reduced pressure, washed with deionized water, and dried under vacuum at 50℃ to obtain a phosphaphenanthrene-based silicon-containing flame retardant. (2) Weigh jade powder and γ-aminopropyltrimethoxysilane at a mass ratio of 1:0.06; mix γ-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water at a mass ratio of 1:20:10 to prepare a silane solution; mix jade powder and anhydrous ethanol at a mass ratio of 1:20, adjust the pH to 4 with formic acid, stir at 50°C for 35 min, add the silane solution, heat to 60°C and stir for 3 h, filter, wash with anhydrous ethanol, and vacuum dry at 70°C to obtain surface-treated jade powder; (3) By weight, there are 96 parts of polyamide 56 chips, 2 parts of surface-treated jade powder, and 5 parts of phosphanium-phenylene-based silicon-containing flame retardant. The polyamide 56 chips, surface-treated jade powder, and phosphanium-phenylene-based silicon-containing flame retardant are placed in a high-speed mixer and stirred at 800 r / min for 15 min. The mixture is then placed in a screw extruder for extrusion granulation at a temperature of 260°C and a screw speed of 50 r / min to obtain polyamide masterbatch. The polyamide masterbatch is then placed in a spinning machine for melt spinning to obtain polyamide fiber. (4) Mix protocatechuic acid, p-toluenesulfonic acid monohydrate and N,N-dimethylformamide in a mass ratio of 1:0.003:20 to prepare a finishing solution; place the polyamide fiber in a 36% formaldehyde aqueous solution with a bath ratio of 1:20, stir at 85°C for 80 min under nitrogen protection, remove, wash with deionized water, dry at 60°C for 2 h, then place in the finishing solution with a bath ratio of 1:20, stir at 80°C for 2 h under nitrogen protection, raise the temperature to 100°C, continue stirring for 80 min, remove, wash with hot water at 80°C, and dry at 60°C to obtain cool-feeling polyamide fiber. Example 2:

[0026] This embodiment provides a method for preparing cool-feeling polyamide fibers, including the following preparation steps: (1) Weigh phenyltrichlorosilane, triethylamine, and 2-hydroxyethyl acrylate in a molar ratio of 1:3:3.15; dissolve 2-hydroxyethyl acrylate and triethylamine in acetonitrile at 7 times the mass of 2-hydroxyethyl acrylate, stir at room temperature for 15 min, heat to 55℃, add phenyltrichlorosilane at a uniform rate over 1 h, and continue stirring for 5.5 h after the addition is complete, filter, and evaporate the filtrate under reduced pressure to obtain the intermediate; weigh the intermediate and 9,10-dihydro-9-oxa-10 in a molar ratio of 1:3. -phosphaphenanthrene-10-sulfide; the intermediate and dioxane were mixed in a mass ratio of 1:5 to prepare a reaction solution; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide, triethylamine and dioxane were mixed in a mass ratio of 1:0.025:5, heated to 45℃, and the reaction solution was added dropwise at a uniform rate over 40 min. After the addition was completed, the temperature was raised to 75℃, and the reaction was continued with stirring for 12.5 h. The mixture was then evaporated under reduced pressure, washed with deionized water, and dried under vacuum at 55℃ to obtain a phosphaphenanthrene-based silicon-containing flame retardant. (2) Weigh jade powder and γ-aminopropyltrimethoxysilane at a mass ratio of 1:0.07; mix γ-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water at a mass ratio of 1:25:12 to prepare a silane solution; mix jade powder and anhydrous ethanol at a mass ratio of 1:25, adjust the pH to 4.5 with formic acid, stir at 55℃ for 30 min, add the silane solution, heat to 65℃ and stir for 2.5 h, filter, wash with anhydrous ethanol, and vacuum dry at 75℃ to obtain surface-treated jade powder; (3) By weight, there are 98 parts of polyamide 56 chips, 2.5 parts of surface-treated jade powder, and 5.5 parts of phosphanium-phenanthroline silicon-containing flame retardant. The polyamide 56 chips, surface-treated jade powder, and phosphanium-phenanthroline silicon-containing flame retardant are placed in a high-speed mixer and stirred at 1100 r / min for 13 min. The mixture is then placed in a screw extruder for extrusion granulation at an extrusion temperature of 265℃ and a screw speed of 55 r / min to obtain polyamide masterbatch. The polyamide masterbatch is then placed in a spinning machine for melt spinning to obtain polyamide fiber. (4) Mix protocatechuic acid, p-toluenesulfonic acid monohydrate and N,N-dimethylformamide in a mass ratio of 1:0.004:21 to prepare a finishing solution; place the polyamide fiber in a 36% formaldehyde aqueous solution with a bath ratio of 1:25, stir at 90°C for 70 min under nitrogen protection, remove, wash with deionized water, dry at 65°C for 1.5 h, then place in the finishing solution with a bath ratio of 1:25, stir at 85°C for 1.5 h under nitrogen protection, raise the temperature to 105°C, continue stirring for 75 min, remove, wash with hot water at 85°C, and dry at 65°C to obtain cool-feeling polyamide fiber. Example 3:

[0027] This embodiment provides a method for preparing cool-feeling polyamide fibers, including the following preparation steps: (1) Weigh phenyltrichlorosilane, triethylamine, and 2-hydroxyethyl acrylate in a molar ratio of 1:3:3.2; dissolve 2-hydroxyethyl acrylate and triethylamine in acetonitrile in 8 times the mass of 2-hydroxyethyl acrylate, stir at room temperature for 20 min, heat to 60℃, add phenyltrichlorosilane at a uniform rate over 1 h, and continue stirring for 5 h after the addition is complete, filter, and evaporate the filtrate under reduced pressure to obtain the intermediate; weigh the intermediate and 9,10-dihydro-9-oxa-10 in a molar ratio of 1:3. -phosphaphenanthrene-10-sulfide; the intermediate and dioxane were mixed in a mass ratio of 1:6 to prepare a reaction solution; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide, triethylamine and dioxane were mixed in a mass ratio of 1:0.03:6, heated to 50℃, and the reaction solution was added dropwise at a uniform rate over 40 min. After the addition was completed, the temperature was raised to 80℃, and the reaction was continued with stirring for 10 h. The mixture was then evaporated under reduced pressure, washed with deionized water, and dried under vacuum at 60℃ to obtain a phosphaphenanthrene-based silicon-containing flame retardant. (2) Weigh jade powder and γ-aminopropyltrimethoxysilane at a mass ratio of 1:0.08; mix γ-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water at a mass ratio of 1:30:14 to prepare a silane solution; mix jade powder and anhydrous ethanol at a mass ratio of 1:30, adjust the pH to 5 with formic acid, stir at 60°C for 25 min, add the silane solution, heat to 70°C and stir for 2 h, filter, wash with anhydrous ethanol, and vacuum dry at 80°C to obtain surface-treated jade powder; (3) By weight, 100 parts of polyamide 56 chips, 3 parts of surface-treated jade powder, and 6 parts of phosphanium-phenanthroline silicon-containing flame retardant were placed in a high-speed mixer and stirred at 1400 r / min for 10 min. The mixture was then extruded and granulated in a screw extruder at an extrusion temperature of 270°C and a screw speed of 60 r / min to obtain polyamide masterbatch. The polyamide masterbatch was then melt-spun in a spinning machine to obtain polyamide fiber. (4) Mix protocatechuic acid, p-toluenesulfonic acid monohydrate and N,N-dimethylformamide in a mass ratio of 1:0.005:22 to prepare a finishing solution; place the polyamide fiber in a 36% formaldehyde aqueous solution with a bath ratio of 1:20, stir at 95°C for 60 min under nitrogen protection, remove, wash with deionized water, dry at 70°C for 1 h, then place in the finishing solution with a bath ratio of 1:30, stir at 90°C for 1 h under nitrogen protection, raise the temperature to 110°C, continue stirring for 70 min, remove, wash with hot water at 90°C, and dry at 70°C to obtain cool-feeling polyamide fiber.

[0028] Comparative Example 1 This embodiment provides a method for preparing cool-feeling polyamide fiber. The specific implementation method is the same as that in embodiment 2. The difference from embodiment 2 is that step (1) is not performed, and "phosphorus-containing silicon flame retardant" is not added when preparing polyamide masterbatch in step (3).

[0029] Comparative Example 2 This embodiment provides a method for preparing cool-feeling polyamide fiber. The specific implementation method is the same as that in embodiment 2. The difference from embodiment 2 is that step (2) is not performed, and "surface-treated jade powder" is not added when preparing polyamide masterbatch in step (3).

[0030] Comparative Example 3 This embodiment provides a method for preparing a cooling polyamide fiber. The specific implementation method is the same as that in embodiment 2. The difference from embodiment 2 is that step (4) is not performed, and the "polyamide fiber" prepared in step (3) is used as the "cooling polyamide fiber".

[0031] Performance Evaluation 1. Cooling properties: The cooling polyamide fibers prepared in the examples and comparative examples were spun on a textile machine to a surface density of 180 g / m². 2 Fabric samples were tested using a 20cm x 20cm sample. A KES-F7 contact temperature and humidity sensor (manufactured by Japan's Kado Technology Co., Ltd.) was used. Following the national standard GB / T6529-2008 "Standard Atmospheric Pressure for Conditioning and Testing of Textiles," the samples were placed in a 20℃, 65% constant temperature and humidity chamber for 24 hours to equilibrate. The samples were then placed on a sample stage, and a heatable copper plate was used to contact the sample surface, which had a certain temperature difference. The upper heating plate was set at 20.0℃ ± 0.1℃, and the lower heating plate at 30.0℃ ± 0.1℃, ensuring a temperature difference of 10℃ between the upper and lower heating plates. The maximum heat transferred from the heating plate to the sample during the test was defined as the contact temperature and humidity value. Five different locations were selected for testing on each sample, and the average value was taken as the Q-max value of the fabric.

[0032] 2. Antibacterial properties: According to GB / T20944.3—2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", 0.75g of the sample was weighed, sterilized, and placed in an Erlenmeyer flask containing Escherichia coli. The flask was shaken at 24℃ and 150r / min for 18h in a constant temperature shaker. Then, the bacterial solution was taken from the Erlenmeyer flask and transferred to a test tube, diluted 6 times using the 10-fold dilution method. 1mL of each dilution was then taken and placed into a culture medium. The solutions were incubated at 37℃ for 24h. Finally, the colony counts of the different dilutions in the culture medium were recorded, and the inhibition rate Y was calculated using the formula. In the formula, W represents the average viable bacterial concentration (CFU / mL) in the Erlenmeyer flask after 18h of shaking contact with the blank control sample; Q is the average viable bacterial concentration (CFU / mL) in the Erlenmeyer flask after 18h of shaking contact with the fiber sample.

[0033] 3. Flame retardant performance: According to GB / T5454—1997 "Test for flammability of textiles - Oxygen Index Method", the LOI value of fabrics made of fibers is tested using a limiting oxygen index meter.

[0034] The experimental data characterized above are shown in Table 1.

[0035] Table 1

[0036] Based on the above test data, it can be seen that this application improves the cooling properties of polyamide fibers by adding jade powder, improves the flame retardancy of polyamide fibers by adding phosphaphenanthrene-based silicon-containing flame retardants, and improves the antibacterial ability of polyamide fibers by grafting protocatechuic acid onto the surface of polyamide fibers.

[0037] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended technical solutions rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the technical solutions are intended to be included within the present invention.

Claims

1. A method for preparing a cooling polyamide fiber, characterized in that, The preparation steps include the following: (1) Weigh the intermediate and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide at a molar ratio of 1:3; mix the intermediate and dioxane at a mass ratio of 1:(4~6) to prepare a reaction solution; mix 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide, triethylamine and dioxane at a mass ratio of 1:(0.02~0.03):(4~6), heat to 40~50℃, add the reaction solution dropwise at a uniform rate within 40 min, and after the dropwise addition is completed, heat to 70~80℃, continue stirring and reacting for 10~15 h, evaporate under reduced pressure, wash and dry to obtain phosphaphenanthrene-based silicon-containing flame retardant; (2) Weigh jade powder and γ-aminopropyltrimethoxysilane at a mass ratio of 1:(0.06~0.08); mix γ-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water at a mass ratio of 1:(20~30):(10~14) to prepare a silane solution; mix jade powder and anhydrous ethanol at a mass ratio of 1:(20~30), adjust the pH to 4~5 with formic acid, stir at 50~60℃ for 25~35min, add the silane solution, heat to 60~70℃ and stir for 2~3h, filter, wash and dry to obtain surface-treated jade powder; (3) By weight, there are 96-100 parts of polyamide 56 chips, 2-3 parts of surface-treated jade powder, and 5-6 parts of phosphanium-phenanthroline silicon-containing flame retardant; the polyamide 56 chips, surface-treated jade powder, and phosphanium-phenanthroline silicon-containing flame retardant are mixed at high speed in a high-speed mixer, and then extruded and granulated in a screw extruder to obtain polyamide masterbatch; the polyamide masterbatch is melt-spun in a spinning machine to obtain polyamide fiber; (4) Place the polyamide fiber in a formaldehyde aqueous solution with a bath ratio of 1:(20~30), stir at 85~95℃ for 60~80min under nitrogen protection, remove, wash, dry at 60~70℃ for 1~2h, then place in a finishing solution with a bath ratio of 1:(20~30), stir at 80~90℃ for 1~2h under nitrogen protection, raise the temperature to 100~110℃, continue stirring for 70~80min, remove, wash with hot water, dry at 60~70℃ to obtain cool-feeling polyamide fiber; The preparation process of the intermediate in step (1) is as follows: phenyltrichlorosilane, triethylamine, and 2-hydroxyethyl acrylate are weighed in a molar ratio of 1:3:(3.1~3.2); 2-hydroxyethyl acrylate and triethylamine are dissolved in acetonitrile in 6~8 times the mass of 2-hydroxyethyl acrylate, stirred at room temperature for 10~20 min, heated to 50~60℃, and phenyltrichlorosilane is added at a uniform rate over 1 h. After the addition is complete, the reaction is continued for 5~6 h. The mixture is then filtered, and the filtrate is evaporated under reduced pressure to obtain the intermediate. The preparation process of the finishing solution in step (4) is as follows: Protocatechuic acid, p-toluenesulfonic acid monohydrate, and N,N-dimethylformamide are mixed evenly in a mass ratio of 1:(0.003~0.005):(20~22) to prepare the finishing solution.

2. The method for preparing a cooling polyamide fiber as described in claim 1, characterized in that, The particle size of the jade powder in step (2) is 400~600nm.

3. The method for preparing a cooling polyamide fiber as described in claim 1, characterized in that, The high-speed mixing speed in step (3) is 800~1400 r / min, and the mixing time is 10~15 min.

4. The method for preparing a cooling polyamide fiber as described in claim 1, characterized in that, The extrusion temperature of the extrusion granulation in step (3) is 260~270℃ and the screw speed is 50~60r / min.

5. The method for preparing a cooling polyamide fiber as described in claim 1, characterized in that, The formaldehyde aqueous solution in step (4) has a mass fraction of 36%.

6. A cooling polyamide fiber, characterized in that, The cooling polyamide fiber is prepared by the method for preparing cooling polyamide fiber according to any one of claims 1-5.

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