Self-cleaning anti-fouling nylon slice and preparation method thereof

Abstract

The invention belongs to the field of nylon fibers, and particularly relates to a self-cleaning anti-fouling nylon slice and a preparation method thereof. The self-cleaning nylon slice provided by the invention comprises polyamide, modified polyamide, a functional filler and a nucleating agent, the modified polyamide is prepared by polymerizing diamine, long carbon chain dibasic acid, a functional monomer containing a silicon-oxygen bond and a functional monomer containing a fluorine ether bond. Fluoroether bonds and silicon-oxygen bonds are introduced into the molecular structure of nylon through the functional monomer containing fluoroether bonds and the functional monomer containing silicon-oxygen bonds, and the silane coupling agent is adopted to modify nano titanium dioxide and graphite carbon nitride, so that the anti-fouling effect and the self-cleaning effect of the nylon are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of nylon fibers, specifically relating to a self-cleaning, stain-resistant nylon chip and its preparation method. Background Technology

[0002] Nylon chips, as an important basic raw material for synthetic fibers and engineering plastics, occupy an important position in automotive interiors, electronics, textiles, aerospace and other fields due to their excellent wear resistance, outstanding mechanical strength, good chemical corrosion resistance and excellent processing performance, and have become one of the key materials driving the development of various industries.

[0003] The molecular structure of nylon chips contains amide groups and functional groups such as amino and carboxyl groups at the molecular ends. This gives nylon a certain degree of polarity, making it prone to interacting with polar stain molecules, thus causing nylon products to easily attract stains. Furthermore, nylon is highly absorbent; when it absorbs moisture, the charge distribution on the fiber surface changes, making it even more susceptible to adsorbing dust, oil, and other contaminants. These stains not only affect the appearance of the product but may also reduce its performance.

[0004] To address the issue of nylon chips being easily stained, current anti-stain treatment methods primarily employ finishing and surface coating. Traditional finishing methods typically involve applying an anti-stain agent to the surface of nylon products, forming a protective film on the fiber surface through chemical or physical action to achieve stain resistance. However, this method suffers from short-lived anti-stain effects; with repeated washing, the anti-stain agent gradually wears off, and the anti-stain performance decreases. Surface coating technology involves applying an anti-stain coating material, such as fluorocarbon or silicone coatings, to the surface of nylon products. While this method can improve the stain resistance of nylon products to some extent, the hardness and flexibility of the coating material are limited, making it susceptible to damage from friction, stretching, and other external forces during use. Once the coating is damaged, the anti-stain performance is lost. Furthermore, the above processes are only suitable for anti-stain treatment of nylon products and not for nylon chips. Therefore, the development of an anti-stain nylon chip is urgently needed.

[0005] Chinese patent application CN115559013A discloses a high-strength, stain-resistant graphene nylon long fiber, comprising nylon fiber, graphene stain-resistant modifier, antioxidant, light stabilizer, and modified silica. The graphene stain-resistant modifier, combined with modified silica, enhances the product's strength and stain resistance. However, the graphene in the stain-resistant modifier has a high specific surface area and strong interlayer van der Waals forces, making it prone to irreversible aggregation. This not only negates the interfacial reinforcement effect of the nanomaterial but also creates stress concentration points within the fiber, affecting its mechanical properties. Furthermore, this approach primarily relies on the low surface energy of graphene and the abrasion resistance of silica for stain resistance, resulting in a simplistic stain-resistant mechanism and poor stain resistance performance. Summary of the Invention

[0006] In order to solve the technical problem of poor anti-fouling effect in the above-mentioned related technologies, the purpose of this invention is to provide a self-cleaning anti-fouling nylon chip and its preparation method.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A self-cleaning, stain-resistant nylon chip comprises the following components in parts by weight: 100-120 parts polyamide, 20-40 parts modified polyamide, 10-15 parts functional filler, and 3-8 parts nucleating agent; wherein the modified polyamide is obtained by polymerization of monomer I, monomer II, monomer III, and monomer V, wherein monomer I is a diamine, monomer II is a long-chain dicarboxylic acid, monomer III is a functional monomer containing silicon-oxygen bonds, and monomer V is a functional monomer containing fluorinated ether bonds.

[0008] In the above scheme, fluorinated ether bonds and silicon-oxygen bonds are introduced into the molecular structure of nylon through functional monomers containing fluorinated ether bonds and functional monomers containing silicon-oxygen bonds. The ether bonds in the fluorinated ether bonds can reduce the rigidity of the perfluorocarbon chain, making it easier for fluorinated groups to accumulate on the nylon surface. This reduces the surface energy of nylon while improving the flexibility of the molecular chain. The presence of fluorinated ether bonds can significantly increase the contact angle of nylon against non-polar oil stains. The bond energy of silicon-oxygen bonds (approximately 460 kJ / mol) is much higher than that of carbon-carbon bonds (348 kJ / mol), and the polarity of silicon-oxygen segments is extremely low. This can significantly weaken the interaction between the nylon material surface and polar molecules. Furthermore, silicon-oxygen segments are not prone to migration or volatilization. Compared with the antifouling modification of surface coatings, introducing silicon-oxygen bonds into the molecular structure of nylon can improve the antifouling durability of nylon. The flexibility of silicon-oxygen segments can also improve the brittleness of nylon, thus improving both antifouling properties and mechanical properties. The long-chain alkyl groups in long-chain dicarboxylic acids exhibit random coiling on the polyamide surface. Their van der Waals forces are much weaker than the hydrogen bonding of the polyamide backbone, effectively reducing the adsorption sites for polar stains on the polyamide surface and improving the stain resistance of nylon chips. Furthermore, the high chemical stability of long-chain alkyl groups can effectively improve the temperature resistance and aging resistance of nylon products.

[0009] Preferably, the silicon-oxygen bond-containing functional monomer is 3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane.

[0010] Preferably, the preparation method of the fluorinated ether functional monomer is as follows: Perfluorohexane and methanol are added to a reaction vessel, nitrogen gas is introduced, the temperature of the reaction vessel is lowered to -10 to -5°C, potassium hydroxide is added, and after stirring for 10 to 20 minutes, perfluoropropylene oxide is added dropwise at a rate of 0.5 mL / min under stirring. After the addition is complete, the temperature is raised to 20 to 30°C, and the reaction is stirred for 2 to 3 hours. A 10% hydrochloric acid aqueous solution is added to adjust the pH of the system to neutral, and the mixture is allowed to stand and separate into layers. The oil phase is obtained by separation, distillation at 55 to 60°C for 0.5 to 1 hour, and distillation at 120 to 130°C for 1 to 1.5 hours. The mixture is then dried and cooled to obtain the fluorinated ether functional monomer.

[0011] In the above scheme, methanol generates a methoxy anion (CH3O) under the action of potassium hydroxide. - As a nucleophile, it attacks the epoxy ring of perfluoropropylene oxide, causing the epoxy ring to break and form an active intermediate containing a fluorinated ether bond. The active intermediate continues to attack new perfluoropropylene oxide molecules, resulting in a chain ring-opening reaction that forms a polyether alcohol with a fluorinated ether bond at the end of a hydroxyl group.

[0012] More preferably, the molar ratio of methanol, perfluoropropylene oxide and potassium hydroxide in the preparation method of the fluorinated ether functional monomer is (10-13):(1.2-1.5):(0.03-0.07).

[0013] Preferably, the diamine is one of nonanediamine, octanediamine, hexanediamine, and pentanediamine; the long-chain dicarboxylic acid is one of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid. Preferably, the molar ratio of monomer I, monomer II, monomer III and monomer V is 1:(3-5):(0.15-0.23):(0.5-0.8).

[0014] In the above scheme, the amount of silicon-oxygen bonds introduced into the nylon molecular structure and the active functional groups at both ends of the molecular chain are controlled by controlling the molar ratio of monomer I, monomer II and monomer III. In this invention, the excess of monomer II can effectively ensure that the two ends of the nylon molecular chain are carboxyl groups, laying the foundation for the introduction of polyether alcohols containing fluorinated ether bonds.

[0015] Preferably, the modified polyamide is prepared as follows: monomer I and monomer III are added to deionized water at a volume ratio of 1:3, heated to 50-60°C and stirred until homogeneous, then monomer II is added, and the mixture is stirred for 1-1.5 hours. After filtration, the filtrate is added to a reaction vessel, purged with nitrogen three times, heated to 120-140°C, and the pressure inside the reaction vessel is controlled at 0.3-0.5 MPa. The mixture is stirred for 2-2.5 hours, and the water is recovered through a condenser at the top of the vessel. Then, the mixture is heated to 180°C. At 200℃, the pressure is increased to 1.0-1.2MPa at a rate of 0.1MPa / h, and the reaction is stirred for 3-3.5h. The pressure inside the reactor is slowly released to atmospheric pressure, and the temperature is further increased to 220-240℃. The vacuum is evacuated to an absolute pressure of 50-100Pa, and the reaction is stirred for 4-6h (while removing the water generated in the reaction). Monomer V and catalyst scandium trifluoromethanesulfonate are added, and the reaction is stirred for 1-2h. Nitrogen gas is introduced, and the melt is granulated by an underwater pelletizer, washed, and dried to obtain modified polyamide.

[0016] Preferably, the preparation method of the functional filler is as follows: dispersing nano-titanium dioxide in an aqueous ethanol solution, adding γ-aminopropyltriethoxysilane, heating to 60-70℃ and stirring for 2-3 hours, allowing to stand and cool, and filtering to obtain modified nano-titanium dioxide; dispersing graphite carbon nitride in toluene, adding γ-glycidoxypropyltrimethoxysilane, heating to 80-85℃ and stirring for 4-5 hours, allowing to stand and cool, and filtering to obtain modified graphite carbon nitride; mixing modified nano-titanium dioxide and modified graphite carbon nitride in a mass ratio of (3-5):(7-11) to obtain the functional filler.

[0017] In the above scheme, silane coupling agents are used to modify nano-titanium dioxide and graphite carbon nitride, effectively improving their compatibility with nylon and preventing the agglomeration of nano-titanium dioxide and graphite carbon nitride from affecting the performance of nylon. Nano-titanium dioxide and graphite carbon nitride are photocatalytically active inorganic particles. Under ultraviolet and visible light irradiation, valence band electrons are excited to the conduction band, forming electron-hole pairs. These conduction band electrons react with oxygen in the air to generate superoxide radicals, which have strong oxidizing properties. These radicals can decompose organic stains adhering to the nylon surface into harmless small molecules, thus achieving a self-cleaning effect. Furthermore, the combined addition of nano-titanium dioxide and graphite carbon nitride forms heterojunctions in the nylon, effectively improving the photocatalytic efficiency of the functional filler.

[0018] More preferably, in the preparation method of the functional filler, the mass ratio of nano-titanium dioxide to γ-aminopropyltriethoxysilane is (18-20):(3-7); and the mass ratio of graphite carbon nitride to γ-glycidoxypropyltrimethoxysilane is (15-19):(4-8).

[0019] Preferably, the nucleating agent is one of sodium adipic acid, calcium adipic acid, sodium succinate, and calcium succinate.

[0020] In the above scheme, dicarboxylate is used as a nucleating agent to provide heterogeneous crystal nuclei, accelerate the crystallization rate, significantly improve the rigidity and heat distortion temperature of the material, refine the spherulite size, and improve the surface gloss of nylon.

[0021] The present invention also provides a method for preparing the self-cleaning anti-fouling nylon chips, specifically: mixing polyamide and modified polyamide, heating and melting, adding functional fillers and nucleating agents, mixing evenly, and then extruding and granulating to obtain self-cleaning anti-fouling nylon chips.

[0022] The above scheme, by mixing the matrix with modifiers and fillers, endows nylon with highly efficient self-cleaning and anti-fouling functions while retaining its original properties. It also has strong process compatibility and is suitable for industrial promotion.

[0023] Compared with the prior art, the self-cleaning anti-fouling nylon chips and their preparation method provided by the present invention have the following technical advantages: (1) The present invention uses modified polyamide, functional filler and polyamide blend to make the nylon chips have good anti-fouling and self-cleaning effects; (2) The present invention introduces fluorinated ether bonds and silicon-oxygen bonds into the molecular structure of nylon through functional monomers containing fluorinated ether bonds and functional monomers containing silicon-oxygen bonds, thereby improving the anti-fouling effect of nylon chips; (3) The present invention uses silane coupling agent to modify nano titanium dioxide and graphite carbon nitride, which effectively improves the compatibility and self-cleaning effect of nano titanium dioxide and graphite carbon nitride with nylon. Attached Figure Description

[0024] Figure 1 The hydrogen spectrum of the fluorinated ether functional monomer obtained in Example 3; Figure 2 The image shows the infrared spectrum of the modified polyamide prepared in Example 3. Detailed Implementation

[0025] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments. Those skilled in the art can make various modifications based on the fundamental principles of the present invention, but all modifications that do not depart from the fundamental principles of the present invention are within its scope.

[0026] Example 1 A self-cleaning, stain-resistant nylon chip comprises the following components in parts by weight: 100g polyamide, 20g modified polyamide, 10g functional filler, and 3g sodium adipic acid; wherein the modified polyamide is obtained by polymerization of monomer I, monomer II, monomer III, and monomer V, wherein monomer I is nonanediamine, monomer II is dodecanoic acid, monomer III is a silicon-oxygen bond-containing functional monomer 3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and monomer V is a fluorinated ether bond-containing functional monomer.

[0027] The preparation method of the fluorinated ether functional monomer is as follows: 500 mL of perfluorohexane and 10 mol of methanol are added to a reaction vessel, nitrogen gas is introduced, the temperature of the reaction vessel is lowered to -10℃, 0.03 mol of potassium hydroxide is added, and after stirring for 10 min, 1.2 mol of perfluoropropylene oxide is added dropwise at a rate of 0.5 mL / min under stirring. After the addition is completed, the temperature is raised to 20℃, and the reaction is stirred for 2 h. A 10% hydrochloric acid aqueous solution is added to adjust the pH of the system to neutral, and the mixture is allowed to stand and separate into layers. The lower aqueous phase is removed by separation to obtain the oil phase. The oil phase is washed with deionized water until the pH of the washing solution is neutral. The oil phase is distilled at 55℃ and 0.01 MPa for 0.5 h and at 120℃ and 0.001 MPa for 1 h. The oil phase is then placed in a vacuum drying oven and dried at 60℃ and 0.01 MPa for 4 h. After cooling, the fluorinated ether functional monomer is obtained.

[0028] The modified polyamide is prepared as follows: 10 mol of monomer I and 1.5 mol of monomer III are added to deionized water at a volume ratio of 1:3. The mixture is heated to 50°C and stirred until homogeneous. Then, 30 mol of monomer II is added, and the mixture is stirred for 1 hour. After filtration, the filtrate is added to a reaction vessel, purged with nitrogen three times, heated to 120°C, and the pressure inside the reaction vessel is controlled at 0.3 MPa. The mixture is stirred for 2 hours, and the water is recovered and removed through a condenser at the top of the vessel. Then, the mixture is heated to 180°C at 0.1 MPa / The pressure was increased to 1.0 MPa at a rate of h, and the reaction was stirred for 3 h. The pressure inside the reactor was slowly released to atmospheric pressure, and the temperature was further increased to 220 °C. The vacuum was then drawn to an absolute pressure of 50 Pa, and the reaction was stirred for 4 h. The water was recovered and removed through the condenser at the top of the reactor. 5 mol of monomer V and 1 mol of catalyst scandium trifluoromethanesulfonate were added, and the reaction was stirred for 1 h. Nitrogen gas was introduced, and the melt was granulated by an underwater pelletizer. The melt was washed three times with deionized water, dried at 80 °C with forced air for 2 h, and then dried under vacuum at 120 °C for 6 h to obtain modified polyamide.

[0029] The preparation method of the functional filler is as follows: 18g of nano-titanium dioxide is dispersed in 50mL of ethanol aqueous solution, 3g of γ-aminopropyltriethoxysilane is added, the temperature is raised to 60℃ and stirred for 2h, the mixture is allowed to stand and cool, and then filtered to obtain modified nano-titanium dioxide; 15g of graphite carbon nitride is dispersed in toluene, 4g of γ-glycidoxypropyltrimethoxysilane is added, the temperature is raised to 80℃ and stirred for 4h, the mixture is allowed to stand and cool, and then filtered to obtain modified graphite carbon nitride; the modified nano-titanium dioxide and modified graphite carbon nitride are mixed at a mass ratio of 3:7 to obtain the functional filler.

[0030] The preparation method of self-cleaning anti-fouling nylon chips is as follows: Polyamide and modified polyamide are fed into the main feed port of a twin-screw extruder. The temperatures of each section of the screw are set as follows: feeding section 180℃, compression section 220℃, melting section 240℃, and screw speed 200 rpm. Functional filler and nucleating agent are added through the side feed port. The screw speed is increased to 300 rpm. After mixing for 10 minutes, the mixture is extruded through the die. The melt pressure is controlled at 10 MPa. The extruded melt is pelletized underwater (water temperature 60℃), then dried in a forced-air dryer at 80℃ for 2 hours, and then vacuum dried at 120℃ for 6 hours to obtain self-cleaning anti-fouling nylon chips.

[0031] Example 2 A self-cleaning, stain-resistant nylon chip comprises the following components in parts by weight: 120g polyamide, 40g modified polyamide, 15g functional filler, and 8g calcium adipic acid; wherein the modified polyamide is obtained by polymerization of monomer I, monomer II, monomer III, and monomer V, wherein monomer I is octanediamine, monomer II is hexadecanoic acid, monomer III is a functional monomer containing silicon-oxygen bonds, 3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and monomer V is a functional monomer containing fluorinated ether bonds.

[0032] The preparation method of the fluorinated ether functional monomer is as follows: 500 mL of perfluorohexane and 13 mol of methanol are added to a reaction vessel, nitrogen gas is introduced, the temperature of the reaction vessel is lowered to -5℃, 0.07 mol of potassium hydroxide is added, and after stirring for 20 min, 1.5 mol of perfluoropropylene oxide is added dropwise at a rate of 0.5 mL / min under stirring. After the addition is completed, the temperature is raised to 30℃, and the reaction is stirred for 3 h. A 10% hydrochloric acid aqueous solution is added to adjust the pH of the system to neutral, and the mixture is allowed to stand and separate into layers. The lower aqueous phase is removed by separation to obtain the oil phase. The oil phase is washed with deionized water until the pH of the washing solution is neutral. The oil phase is distilled at 60℃ and 0.01 MPa for 1 h, and then at 130℃ and 0.001 MPa for 1.5 h. The oil phase is then placed in a vacuum drying oven and dried at 60℃ and 0.01 MPa for 4 h. After cooling, the fluorinated ether functional monomer is obtained.

[0033] The modified polyamide is prepared as follows: 10 mol of monomer I and 2.3 mol of monomer III are added to deionized water at a volume ratio of 1:3. The mixture is heated to 60°C and stirred until homogeneous. Then, 50 mol of monomer II is added and the mixture is stirred for 1.5 h. After filtration, the filtrate is added to a reaction vessel, purged with nitrogen three times, heated to 140°C, and the pressure inside the reaction vessel is controlled at 0.5 MPa. The mixture is stirred for 2.5 h, and the water is recovered and removed through a condenser on the top of the vessel. Then, the mixture is heated to 200°C at 0.1 MPa. The pressure was increased to 1.2 MPa at a rate of / h, and the reaction was stirred for 3.5h. The pressure inside the reactor was slowly released to atmospheric pressure, and the temperature was further increased to 240℃. The vacuum was then drawn to an absolute pressure of 100 Pa, and the reaction was stirred for 6h. The water was recovered and removed through the condenser at the top of the reactor. 8 mol of monomer V and 1 mol of catalyst scandium trifluoromethanesulfonate were added, and the reaction was stirred for 2h. Nitrogen gas was introduced, and the melt was granulated by an underwater pelletizer. The melt was washed three times with deionized water, dried at 80℃ for 2h, and then dried under vacuum at 120℃ for 6h to obtain modified polyamide.

[0034] The preparation method of the functional filler is as follows: 20g of nano-titanium dioxide is dispersed in 50mL of ethanol aqueous solution, 7g of γ-aminopropyltriethoxysilane is added, the temperature is raised to 70℃ and stirred for 3h, the mixture is allowed to stand and cool, and then filtered to obtain modified nano-titanium dioxide; 19g of graphite carbon nitride is dispersed in toluene, 8g of γ-glycidoxypropyltrimethoxysilane is added, the temperature is raised to 85℃ and stirred for 5h, the mixture is allowed to stand and cool, and then filtered to obtain modified graphite carbon nitride; the modified nano-titanium dioxide and modified graphite carbon nitride are mixed at a mass ratio of 5:11 to obtain the functional filler.

[0035] The preparation method of self-cleaning anti-fouling nylon chips is as follows: Polyamide and modified polyamide are fed into the main feed port of a twin-screw extruder. The temperatures of each section of the screw are set as follows: 200℃ for the feeding section, 240℃ for the compression section, and 250℃ for the melting section. The screw speed is set to 200 rpm. Functional fillers and nucleating agents are added through the side feed port. The screw speed is increased to 300 rpm. After mixing for 20 minutes, the mixture is extruded through the die. The melt pressure is controlled at 15 MPa. The extruded melt is pelletized underwater (water temperature 80℃), then dried in a forced-air dryer at 80℃ for 2 hours, and then vacuum dried at 120℃ for 6 hours to obtain self-cleaning anti-fouling nylon chips.

[0036] Example 3 A self-cleaning, stain-resistant nylon chip comprises the following components in parts by weight: 115g polyamide, 32g modified polyamide, 12g functional filler, and 5g sodium octanoate; wherein the modified polyamide is obtained by polymerization of monomer I, monomer II, monomer III, and monomer V, wherein monomer I is pentanediamine, monomer II is octadecanoic acid, monomer III is a silicon-oxygen bond-containing functional monomer 3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and monomer V is a fluorinated ether bond-containing functional monomer.

[0037] The preparation method of the fluorinated ether functional monomer is as follows: 500 mL of perfluorohexane and 12 mol of methanol are added to a reaction vessel, nitrogen gas is introduced, the temperature of the reaction vessel is lowered to -8℃, 0.05 mol of potassium hydroxide is added, and after stirring for 15 min, 1.4 mol of perfluoropropylene oxide is added dropwise at a rate of 0.5 mL / min under stirring. After the addition is completed, the temperature is raised to 28℃, and the reaction is stirred for 2.5 h. A 10% hydrochloric acid aqueous solution is added to adjust the pH of the system to neutral, and the mixture is allowed to stand and separate into layers. The lower aqueous phase is removed by separation to obtain the oil phase. The oil phase is washed with deionized water until the pH of the washing solution is neutral. The oil phase is distilled at 58℃ and 0.01 MPa for 0.8 h and at 125℃ and 0.001 MPa for 1.2 h. The oil phase is then placed in a vacuum drying oven and dried at 60℃ and 0.01 MPa for 4 h. After cooling, the fluorinated ether functional monomer is obtained.

[0038] The modified polyamide is prepared as follows: 10 mol of monomer I and 1.9 mol of monomer III are added to deionized water at a volume ratio of 1:3. The mixture is heated to 55°C and stirred until homogeneous. Then, 40 mol of monomer II is added, and the mixture is stirred for 1.3 h. After filtration, the filtrate is added to a reaction vessel, purged with nitrogen three times, heated to 135°C, and the pressure inside the reaction vessel is controlled at 0.4 MPa. The mixture is stirred for 2.2 h, and the water is recovered and removed through a condenser on the top of the vessel. Then, the mixture is heated to 190°C at 0.1 MPa / The pressure was increased to 1.1 MPa at a rate of h, and the reaction was stirred for 3.2 h. The pressure inside the reactor was slowly released to atmospheric pressure, and the temperature was further increased to 230 °C. The vacuum was then drawn to an absolute pressure of 80 Pa, and the reaction was stirred for 5 h. The water was recovered and removed through the condenser at the top of the reactor. 7 mol of monomer V and 1 mol of catalyst scandium trifluoromethanesulfonate were added, and the reaction was stirred for 1.5 h. Nitrogen gas was introduced, and the melt was granulated by an underwater pelletizer. The melt was washed three times with deionized water, dried at 80 °C with forced air for 2 h, and then dried under vacuum at 120 °C for 6 h to obtain the modified polyamide.

[0039] The preparation method of the functional filler is as follows: 19g of nano-titanium dioxide is dispersed in 50mL of ethanol aqueous solution, 6g of γ-aminopropyltriethoxysilane is added, the temperature is raised to 65℃ and stirred for 2.5h, the mixture is allowed to stand and cool, and then filtered to obtain modified nano-titanium dioxide; 18g of graphite carbon nitride is dispersed in toluene, 6g of γ-glycidoxypropyltrimethoxysilane is added, the temperature is raised to 84℃ and stirred for 4.5h, the mixture is allowed to stand and cool, and then filtered to obtain modified graphite carbon nitride; the modified nano-titanium dioxide and modified graphite carbon nitride are mixed at a mass ratio of 4:9 to obtain the functional filler.

[0040] The preparation method of self-cleaning anti-fouling nylon chips is as follows: Polyamide and modified polyamide are fed into the main feed port of a twin-screw extruder. The temperatures of each section of the screw are set as follows: feeding section 190℃, compression section 230℃, melting section 245℃, and screw speed 200 rpm. Functional filler and nucleating agent are added through the side feed port. The screw speed is increased to 300 rpm. After mixing for 15 minutes, the mixture is extruded through the die. The melt pressure is controlled at 12 MPa. The extruded melt is pelletized underwater (water temperature 70℃), then dried in a forced-air dryer at 80℃ for 2 hours, and then vacuum dried at 120℃ for 6 hours to obtain self-cleaning anti-fouling nylon chips.

[0041] Comparative Example 1 In this comparative example, the nylon chips and their preparation method are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of polyamide is used instead of modified polyamide in this comparative example.

[0042] Comparative Example 2 The nylon chips and their preparation method in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of polyamide is used to replace the functional filler in this comparative example.

[0043] Comparative Example 3 The nylon chips and their preparation method in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that in the preparation method of the modified polyamide in this comparative example, an equal amount of deionized water is used to replace monomer V.

[0044] Comparative Example 4 The nylon chips and their preparation method in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of deionized water is used to replace monomer III in the preparation method of the modified polyamide in this comparative example.

[0045] Comparative Example 5 The nylon chips and their preparation method in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that the functional filler in this comparative example is modified nano-titanium dioxide.

[0046] Test case The nylon chips obtained in Examples 1-3 and Comparative Examples 1-5 were melt-spun into 70D / 24f FDY fibers, which were then woven into stockings for stain resistance testing. The tensile mechanical properties of the materials were tested using a universal testing machine according to the method described in GB / T1040.2-2022; the stain resistance was evaluated using the method described in FZ / T01118—2012 "Detection and Evaluation of Stain Resistance of Textiles - Ease of Stain Removal". The test results are shown in Table 1.

[0047] Table 1 Performance Test Results

[0048] As shown in Table 1, the self-cleaning, stain-resistant nylon chips provided by this invention introduce hydrophobic silicon-oxygen bond structures within the molecule, significantly improving the tensile properties of the nylon material. This ensures good flexibility in the nylon, reduces its adhesion to stains, and thus enhances its stain resistance. The self-cleaning, stain-resistant nylon chips also introduce fluoroether bond structures within the molecule, giving the nylon material excellent and durable stain resistance. Furthermore, the modified nano-titanium dioxide and modified graphite carbon nitride in the functional fillers provide the nylon material with excellent self-cleaning properties, further improving its stain resistance.

[0049] In addition, the present invention also performed NMR spectroscopy on the fluorinated ether functional monomers obtained in Example 3, and the test results are shown in [Figure 1]. Figure 1 The modified polyamide prepared in Example 3 was subjected to infrared spectroscopy testing, and the test results are shown in [Figure 3]. Figure 2 .Depend on Figure 1 It can be seen that the chemical shift δ of 3.2989–3.3025 ppm corresponds to the characteristic peak of methoxy-OCH3, and the chemical shift δ of 1.0987–1.1135 ppm corresponds to the characteristic peak of terminal -CH2OH. From Figure 2 It can be seen that at 3015cm -1 The characteristic peak of C=O in the amide bond appeared at 1324 cm⁻¹. -1 The characteristic peak of NH in the amide bond appeared at 2503 cm⁻¹. -1 2567cm -1 A characteristic peak of -CH2 appeared at 1023 cm⁻¹. -1 The characteristic peak of Si-O-Si appeared at 1096 cm⁻¹. -1 The characteristic peak of -CF2CF(CF3)-O- appeared at 1261 cm⁻¹. -1 The presence of the characteristic peak -CF3 indicates that the modified polyamide synthesized in this invention contains silicon-oxygen bonds and fluorinated ether bonds in its molecular structure, and that all the reactants participated in the polymerization reaction.

[0050] The above embodiments are merely illustrative of the present invention and are not intended to limit the invention. Those skilled in the art should not modify the above embodiments without departing from the spirit and scope of the present invention. All equivalent modifications or alterations made by those skilled in the art without departing from the technical concept of the present invention are still within the protection scope of the present invention.

Claims

1. A self-cleaning, stain-resistant nylon chip, characterized in that, The product comprises the following components in parts by weight: 100-120 parts polyamide, 20-40 parts modified polyamide, 10-15 parts functional filler, and 3-8 parts nucleating agent; wherein the modified polyamide is obtained by polymerization of monomer I, monomer II, monomer III, and monomer V, wherein monomer I is a diamine, monomer II is a long-chain dicarboxylic acid, monomer III is a functional monomer containing silicon-oxygen bonds, and monomer V is a functional monomer containing fluorinated ether bonds.

2. The self-cleaning, stain-resistant nylon chip according to claim 1, characterized in that, The silicon-oxygen bond-containing functional monomer is 3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; the nucleating agent is one of sodium adipic acid, calcium adipic acid, sodium succinate, and calcium succinate.

3. The self-cleaning, stain-resistant nylon chip according to claim 1, characterized in that, The preparation method of the fluorinated ether functional monomer is as follows: Perfluorohexane and methanol are added to a reaction vessel, nitrogen gas is introduced, the temperature of the reaction vessel is lowered to -10 to -5℃, potassium hydroxide is added, and after stirring for 10 to 20 min, perfluoropropylene oxide is added dropwise at a rate of 0.5 mL / min under stirring. After the addition is completed, the temperature is raised to 20 to 30℃, and the reaction is stirred for 2 to 3 h. A 10% hydrochloric acid aqueous solution is added to adjust the pH of the system to neutral, and the mixture is allowed to stand and separate into layers. The oil phase is obtained by separation, distillation at 55 to 60℃ for 0.5 to 1 h, and distillation at 120 to 130℃ for 1 to 1.5 h. After drying and cooling, the fluorinated ether functional monomer is obtained.

4. The self-cleaning, stain-resistant nylon chip according to claim 3, characterized in that, The molar ratio of methanol, perfluoropropylene oxide and potassium hydroxide in the preparation method of the fluorinated ether functional monomer is (10-13):(1.2-1.5):(0.03-0.07).

5. The self-cleaning, stain-resistant nylon chip according to claim 1, characterized in that, The diamine is one of nonanediamine, octanediamine, hexanediamine, and pentanediamine; the long-chain dicarboxylic acid is one of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid.

6. The self-cleaning, stain-resistant nylon chip according to claim 1, characterized in that, The molar ratio of monomer I, monomer II, monomer III and monomer V is 1:(3-5):(0.15-0.23):(0.5-0.8).

7. The self-cleaning, stain-resistant nylon chip according to claim 1, characterized in that, The modified polyamide is prepared as follows: monomer I and monomer III are added to deionized water at a volume ratio of 1:

3. The mixture is heated to 50-60°C and stirred until homogeneous. Then, monomer II is added, and the mixture is stirred for 1-1.5 hours. After filtration, the filtrate is added to a reaction vessel, purged with nitrogen three times, and heated to 120-140°C. The pressure inside the reaction vessel is controlled at 0.3-0.5 MPa, and the mixture is stirred for 2-2.5 hours. Water is recovered through a condenser at the top of the vessel, and then the mixture is heated to 180-200°C. At 0℃, the pressure is increased to 1.0-1.2MPa at a rate of 0.1MPa / h, and the reaction is stirred for 3-3.5h. The pressure inside the reactor is slowly released to atmospheric pressure, and the temperature is further increased to 220-240℃. The vacuum is evacuated to an absolute pressure of 50-100Pa, and the reaction is stirred for 4-6h (while removing the water generated in the reaction). Monomer V and catalyst scandium trifluoromethanesulfonate are added, and the reaction is stirred for 1-2h. Nitrogen gas is introduced, and the melt is granulated by an underwater pelletizer, washed, and dried to obtain modified polyamide.

8. The self-cleaning, stain-resistant nylon chip according to claim 1, characterized in that, The preparation method of the functional filler is as follows: nano-titanium dioxide is dispersed in an aqueous ethanol solution, γ-aminopropyltriethoxysilane is added, the temperature is raised to 60-70℃ and stirred for 2-3 hours, cooled and filtered to obtain modified nano-titanium dioxide; graphite carbon nitride is dispersed in toluene, γ-glycidoxypropyltrimethoxysilane is added, the temperature is raised to 80-85℃ and stirred for 4-5 hours, cooled and filtered to obtain modified graphite carbon nitride; the modified nano-titanium dioxide and modified graphite carbon nitride are mixed in a mass ratio of (3-5):(7-11) to obtain the functional filler.

9. The self-cleaning, stain-resistant nylon chip according to claim 8, characterized in that, In the preparation method of the functional filler, the mass ratio of nano-titanium dioxide to γ-aminopropyltriethoxysilane is (18-20):(3-7); the mass ratio of graphite carbon nitride to γ-glycidoxypropyltrimethoxysilane is (15-19):(4-8).

10. The method for preparing self-cleaning, stain-resistant nylon chips according to any one of claims 1 to 9, characterized in that, Specifically, polyamide and modified polyamide are mixed, heated and melted, functional fillers and nucleating agents are added, and after being mixed evenly, they are extruded and granulated to obtain self-cleaning anti-fouling nylon chips.

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