Water repellent and breathable nonwoven fabric and method for manufacturing the same

Abstract

The application relates to the field of non-woven fabrics, and discloses a water-repellent and breathable non-woven fabric and a preparation method thereof. The non-woven fabric is made of modified polyester fibers and natural fibers, wherein the modified polyester fibers are made of polyester chips and modified nano titanium dioxide melt spinning; the modified nano titanium dioxide is made by grafting a silicon quaternary ammoniumized cardanol derivative on the surface of nano titanium dioxide; the silicon quaternary ammonized cardanol derivative is made by reacting bromo-epoxy cardanol ether obtained by reacting epoxidized cardanol and 1,2-dibromoethane with N-methyl imidazole, then reacting the obtained epoxy quaternary ammonized cardanol with a modified silane coupling agent, and then reacting the obtained silicon-containing epoxy quaternary ammonized cardanol with chitosan; the modified silane coupling agent is made by reacting gamma-methacryloxypropyl trimethoxysilane with tetramethyldisiloxane, and the non-woven fabric prepared by the application has excellent mechanical properties, water-repellent and breathable properties, antibacterial properties, high-temperature resistance and wear resistance.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven fabric technology, specifically relating to a water-repellent and breathable nonwoven fabric and its preparation method. Background Technology

[0002] Nonwoven fabric is a type of fabric that does not require spinning or weaving. It is made by arranging short or long textile fibers in a directional or random manner to form a web structure, which is then reinforced by mechanical, thermal bonding, or chemical methods. It is a new generation of environmentally friendly material with advantages such as breathability, flexibility, light weight, easy decomposition, rich colors, low price, and recyclability. It is widely used in medical and health, personal care, and filtration materials.

[0003] Existing nonwoven fabrics often suffer from low mechanical strength, which greatly limits their use. Functional nonwoven fabrics are typically prepared by introducing various functional materials, but the uneven dispersion and stacking of these materials often result in poor functionality. Furthermore, nonwoven fabrics themselves are not water-resistant, easily absorbing moisture or failing to provide waterproofing, thus failing to offer adequate protection. With increasing health awareness and a focus on quality of life, the development of nonwoven materials with excellent antibacterial and bacteriostatic properties has received growing attention. However, traditional antibacterial components such as quaternary ammonium salts and silver compounds suffer from insufficient durability and easy loss, and some chemicals may cause allergies or cytotoxicity. Long-term misuse could exacerbate the crisis of microbial resistance. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a water-repellent and breathable nonwoven fabric and its preparation method. The nonwoven fabric is made by needle punching a mixture of natural fibers and modified polyester fibers, resulting in good breathability. The modified polyester fibers are made by melt spinning after melt blending and granulation of polyester chips and modified nano-titanium dioxide. This gives the prepared nonwoven fabric excellent mechanical properties, water repellency and breathability, antibacterial properties, high temperature resistance, and abrasion resistance.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A water-repellent and breathable nonwoven fabric is made of modified polyester fiber and natural fiber needle punching. The modified polyester fiber is prepared by mixing polyester chips and modified nano titanium dioxide to form a modified polyester masterbatch, which is then produced by melt spinning. The modified nano titanium dioxide is made by grafting a silicon-containing quaternized cashew phenol derivative onto the surface of nano titanium dioxide using a chemical reaction.

[0007] The silicon-containing quaternized cashew phenol derivative is prepared by oxidizing cashew phenol to epoxidized cashew phenol with m-chloroperoxybenzoic acid, followed by a substitution reaction with 1,2-dibromoethane to obtain brominated epoxy cashew phenol ether. Then, N-methylimidazolium reacts with the brominated epoxy cashew phenol ether to prepare epoxy quaternized cashew phenol. A modified silane coupling agent is then used to react with the side chain of the epoxy quaternized cashew phenol via hydrosilylation. Subsequently, the prepared silicon-containing epoxy quaternized cashew phenol is reacted with chitosan via a ring-opening reaction. The modified silane coupling agent is prepared by reacting γ-methacryloyloxypropyltrimethoxysilane with tetramethyldisiloxane via hydrosilylation.

[0008] Preferably, the natural fiber is either cotton or linen; the mass ratio of the modified polyester fiber to the natural fiber is 8:1~2.

[0009] Preferably, the mass ratio of the pretreated polyester chips to the modified nano-titanium dioxide is 1:0.05~0.2.

[0010] Preferably, the preparation method of the modified nano-titanium dioxide includes the following steps: nano-titanium dioxide is ultrasonically dispersed in anhydrous ethanol and deionized water, then a silicon-containing quaternized cashew phenol derivative is added, and the mixture is stirred and reacted at 60~85℃ for 10~12h. After the reaction is completed, the mixture is filtered, washed, and dried to obtain modified nano-titanium dioxide.

[0011] Preferably, the preparation method of the silicon-containing quaternized cashew phenol derivative includes the following steps:

[0012] (1) Take γ-methacryloxypropyltrimethoxysilane, tetramethyldisiloxane and toluene solvent in a reactor, introduce nitrogen gas, heat in an oil bath to 75~85℃ under magnetic stirring, then add Wilkinson catalyst and react at a constant temperature for 5~7h. After the reaction is completed, remove the organic solvent by rotary evaporation, and purify the reaction solution by silica gel chromatography column to prepare the modified silane coupling agent.

[0013] (2) In a nitrogen atmosphere, sodium bicarbonate saturated aqueous solution was added dropwise to a dichloromethane solution containing cashew phenol, and the solution was cooled to 0-4°C in an ice-water bath. The m-chloroperoxybenzoic acid was added in batches over 30 min. After reacting for 25-40 min, dichloromethane, sodium bicarbonate saturated aqueous solution and sodium thiosulfate saturated aqueous solution were added to extract the organic phase. The organic phase was then dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation. The solution was then purified by silica gel chromatography to prepare epoxidized cashew phenol.

[0014] (3) Dissolve epoxidized cashew phenol in isopropanol and add it dropwise to a reaction system containing 1,2-dibromoethane, potassium carbonate and isopropanol. Reflux at 85~90℃ for 10~12h. After the reaction is completed, bromoepoxidized cashew phenol ether is prepared by filtration, rotary evaporation and column chromatography.

[0015] (4) Take brominated epoxy cashew ether, N-methylimidazolium and acetonitrile solvent in a reactor, stir and mix, and then react at 60~75℃ for 16~20h. After the reaction is completed, filter, rotary evaporate and column chromatography are used to purify the product to prepare epoxy quaternized cashew ether.

[0016] (5) Take epoxy-quaternized cashew phenol and modified silane coupling agent into a reactor, then add caster catalyst, stir and heat to 105~110℃ for 6~7h, then cool to 75~80℃, add activated carbon and continue the reaction for 0.5~1h, after the reaction is completed, filter and vacuum distill to prepare silicon-containing epoxy-quaternized cashew phenol;

[0017] (6) Chitosan was added to 8wt% sodium hydroxide aqueous solution and 4wt% urea aqueous solution and reacted at -20℃ for 34~36h. Then, silicon-containing epoxy quaternized cashew phenol was added and reacted at 0~4℃ for 10~12h. After neutralization with hydrochloric acid, the mixture was dialyzed with distilled water to prepare silicon-containing quaternized cashew phenol derivative.

[0018] Preferably, the molar ratio of γ-methacryloyloxypropyltrimethoxysilane to tetramethyldisiloxane is 1:1 to 1.3.

[0019] Preferably, the molar ratio of cashew phenol, m-chloroperoxybenzoic acid and 1,2-dibromoethane is 1:1.2~1.5:2.3~2.5.

[0020] Preferably, the molar ratio of the brominated epoxy cashew phenolic ether to N-methylimidazole is 1:1 to 1.1.

[0021] The method for preparing the water-repellent and breathable nonwoven fabric as described above includes the following steps:

[0022] S1. The polyester chips are dried to remove the free water on the surface of the polyester chips and pre-crystallized. Then, the drying is continued to remove the bound water inside the polyester chips to obtain pre-treated polyester chips.

[0023] S2. The pretreated polyester chips and modified nano-titanium dioxide are mixed and then melt-blended and granulated using a twin-screw extruder to obtain modified polyester masterbatch.

[0024] S3. Using a melt spinning machine, the modified polyester masterbatch is extruded from the three-hole spinneret and wound up by a winding machine to obtain modified polyester fiber.

[0025] S4. Modified polyester fiber and natural fiber are added to the opening machine and loosened into cotton-like fibers. During the loosening process, they are mixed and impurities are removed. Then, they are fed into the carding machine using a quantitative feeding method and cross-laid to form a fiber web with the required surface density. The fiber web is then needle-punched to prepare a water-repellent and breathable nonwoven fabric.

[0026] The beneficial effects of this invention are:

[0027] This invention uses a mixture of natural fibers and modified polyester fibers to needle-punch a nonwoven fabric with good air permeability. The modified polyester fibers are made by melt-blending and granulating polyester chips and modified nano-titanium dioxide, followed by melt spinning. This results in a nonwoven fabric with excellent mechanical properties, water repellency and air permeability, antibacterial properties, high temperature resistance and abrasion resistance. This invention utilizes the hydrosilylation reaction of γ-methacryloxypropyltrimethoxysilane with a single-terminal silane-hydrogen bond in tetramethyldisiloxane to prepare a modified silane coupling agent. Simultaneously, this invention utilizes the substitution reaction of 1,2-dibromoethane with the phenolic hydroxyl group in epoxidized cashew nut shells to prepare a brominated epoxy cashew nut shell ether. Then, an N-methylimidazolium reaction is used to quaternize the ungrafted bromine atom in the brominated epoxy cashew nut shell ether to prepare epoxy-quaternized cashew nut shells. Subsequently, an ungrafted silane-hydrogen bond in the modified silane coupling agent is used to hydrosilylate the side chain of the epoxy-quaternized cashew nut shells to prepare a silicon-containing epoxy-quaternized cashew nut shells. Finally, a ring-opening reaction is used with chitosan to prepare a silicon-containing quaternized cashew nut shell derivative.

[0028] This invention prepares a silicon-containing quaternized cashew phenol derivative through chemical modification based on the structural characteristics of cashew phenol. Cashew phenol is a natural phenolic compound containing a unique long-chain alkane in its molecular structure. This silicon-containing quaternized cashew phenol derivative introduces the hydrophobic tail of the long-chain alkane of cashew phenol, a quaternary ammonium salt cation with antibacterial activity, and chitosan with good biocompatibility and antibacterial properties, endowing the fiber fabric with excellent water repellency and antibacterial properties. Simultaneously, the multiple silicon-oxygen bonds (Si-O-Si) introduced can impart good high-temperature resistance and abrasion resistance to the material, and can further improve the water repellency of the fiber fabric. Furthermore, this invention utilizes the silicon-containing... The silanol groups introduced into the quaternized cashew phenol derivative undergo dehydration condensation with the hydroxyl groups on the surface of nano-titanium dioxide after hydrolysis, thus preparing modified nano-titanium dioxide. Nano-titanium dioxide, as an important inorganic ultraviolet shielding agent and antibacterial agent, grafts silicon-containing quaternized cashew phenol derivatives onto the surface of nano-titanium dioxide through strong chemical bonds, improving the dispersion uniformity of nano-titanium dioxide and avoiding the agglomeration of nanoparticles that would lead to a decrease in mechanical properties. In addition, the grafting reaction can avoid the migration and precipitation problems of functional components in silicon-containing quaternized cashew phenol derivatives during long-term use or subsequent processing, which is conducive to exerting a long-term effect. Detailed Implementation

[0029] 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.

[0030] Example 1: A method for preparing modified nano-titanium dioxide includes the following steps:

[0031] 5g of nano-titanium dioxide was ultrasonically dispersed in 90mL of anhydrous ethanol and 20mL of deionized water, and then 4.6g of silicon-containing quaternized cashew phenol derivative was added. The mixture was stirred at 70℃ for 12h. After the reaction was completed, the mixture was filtered, washed and dried to prepare modified nano-titanium dioxide.

[0032] The preparation method of the silicon-containing quaternized cashew phenol derivative includes the following steps:

[0033] (1) Take 7.1g of γ-methacryloxypropyltrimethoxysilane, 5g of tetramethyldisiloxane and 50mL of toluene solvent in a reactor, introduce nitrogen gas, heat to 80℃ in an oil bath under magnetic stirring, then add 5mg of Wilkinson catalyst and react at a constant temperature for 6h. After the reaction is completed, remove the organic solvent by rotary evaporation, and purify the reaction solution by silica gel chromatography column (V hexane:V ethyl acetate = 2:1) to prepare the modified silane coupling agent;

[0034] (2) In a nitrogen atmosphere, 13 mL of sodium bicarbonate saturated aqueous solution was added dropwise to 13 mL of dichloromethane solution containing 1 g of cashew phenol. The solution was cooled to 0 °C in an ice-water bath. 0.86 g of m-chloroperoxybenzoic acid was added in batches over 30 min. After reacting for 30 min, dichloromethane, sodium bicarbonate saturated aqueous solution and sodium thiosulfate saturated aqueous solution were added for extraction to obtain the organic phase. The organic phase was then dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation. The solution was then purified by silica gel chromatography (V petroleum ether: V ethyl acetate = 8:1) to prepare epoxidized cashew phenol.

[0035] (3) Dissolve the prepared epoxidized cashew phenol in 10 mL of isopropanol and add it dropwise to a reaction system containing 1.5 g of 1,2-dibromoethane, 1.1 g of potassium carbonate and 25 mL of isopropanol. Reflux at 90 °C for 12 h. After the reaction is completed, the mixture is purified by filtration, rotary evaporation and column chromatography (V petroleum ether: V ethyl acetate = 10:1) to prepare bromoepoxidized cashew phenol ether.

[0036] (4) Take 1.2g of brominated epoxy cashew ether, 0.24g of N-methylimidazolium and 20mL of acetonitrile solvent in a reactor, stir and mix, and react at 65℃ for 18h. After the reaction is completed, filter, rotary evaporate and column chromatography (V chloromethane: V methanol = 10:1) to prepare epoxy quaternized cashew ether.

[0037] (5) Take 1g of epoxy quaternized cashew phenol and 0.76g of modified silane coupling agent into a reactor, then add caster catalyst (45ppm Pt content), stir and heat to 110℃ for 6h, then cool to 80℃, add 0.02g of activated carbon and continue to react for 1h. After the reaction is completed, filter and distill under reduced pressure to prepare silicon epoxy quaternized cashew phenol;

[0038] (6) Take 2g of chitosan and add it to 100mL of 8wt% sodium hydroxide aqueous solution and 4wt% urea aqueous solution. After reacting at -20℃ for 36h, add 0.8g of silicon-containing epoxy quaternized cashew phenol and react at 0℃ for 12h. After neutralization with hydrochloric acid, dialyze with distilled water to prepare silicon-containing quaternized cashew phenol derivative.

[0039] Example 2: A method for preparing a water-repellent and breathable nonwoven fabric, comprising the following steps:

[0040] S1. Place the polyester chips in an 80°C forced-air oven and dry for 1 hour. Then raise the temperature to 95°C and continue drying for 2 hours to remove the free water on the surface of the polyester chips and perform pre-crystallization. Then place them in a 100°C vacuum oven and dry for 1 hour. Then raise the temperature to 120°C and dry for 24 hours to remove the bound water inside the polyester chips and obtain pretreated polyester chips.

[0041] S2. The pretreated polyester chips and the modified nano-titanium dioxide prepared in Example 1 were mixed at a mass ratio of 1:0.06, and then melt-blended and granulated using a twin-screw extruder to obtain the modified polyester masterbatch.

[0042] S3. Using a melt spinning machine, the modified polyester masterbatch is extruded from the three-hole spinneret and wound up by a winding machine to obtain modified polyester fiber.

[0043] S4. Modified polyester fiber and ramie fiber are added to the opening machine at a mass ratio of 8:1 and loosened into cotton-like fibers. Simultaneously, they are mixed and impurities are removed during the loosening process. Then, the mixture is fed into the carding machine using a quantitative feeding method and a cross-laid web is formed to achieve a density of 125g / m². 2 A fiber web with a surface density of 580 needles / cm² is formed, and then the fiber web is subjected to three needle punches. The first needle punching frequency is 520 r / min, the needle punching depth is 6 mm, and the needle punching density is 580 needles / cm². 2 The second acupuncture session had a frequency of 780 r / min, a depth of 8 mm, and a density of 700 needles / cm².2 The third acupuncture point had a frequency of 920 r / min, a depth of 14 mm, and a density of 850 needles / cm². 2 A water-repellent and breathable nonwoven fabric was prepared.

[0044] Example 3: A method for preparing a water-repellent and breathable nonwoven fabric, comprising the following steps:

[0045] S1. Place the polyester chips in an 80°C forced-air oven and dry for 1 hour. Then raise the temperature to 95°C and continue drying for 2 hours to remove the free water on the surface of the polyester chips and perform pre-crystallization. Then place them in a 100°C vacuum oven and dry for 1 hour. Then raise the temperature to 120°C and dry for 24 hours to remove the bound water inside the polyester chips and obtain pretreated polyester chips.

[0046] S2. The pretreated polyester chips and the modified nano-titanium dioxide prepared in Example 1 were mixed at a mass ratio of 1:0.12, and then melt-blended and granulated using a twin-screw extruder to obtain the modified polyester masterbatch.

[0047] S3. Using a melt spinning machine, the modified polyester masterbatch is extruded from the three-hole spinneret and wound up by a winding machine to obtain modified polyester fiber.

[0048] S4. Modified polyester fiber and ramie fiber are added to the opening machine at a mass ratio of 8:1.5 and loosened into a cotton-like state. Simultaneously, they are mixed and impurities are removed during the loosening process. Then, the mixture is fed into the carding machine using a quantitative feeding method and a cross-laid web is formed to achieve a density of 125 g / m². 2 A fiber web with a surface density of 580 needles / cm² is formed, and then the fiber web is subjected to three needle punches. The first needle punching frequency is 520 r / min, the needle punching depth is 6 mm, and the needle punching density is 580 needles / cm². 2 The second acupuncture session had a frequency of 780 r / min, a depth of 8 mm, and a density of 700 needles / cm². 2 The third acupuncture point had a frequency of 920 r / min, a depth of 14 mm, and a density of 850 needles / cm². 2 A water-repellent and breathable nonwoven fabric was prepared.

[0049] Example 4: A method for preparing a water-repellent and breathable nonwoven fabric, comprising the following steps:

[0050] S1. Place the polyester chips in an 80°C forced-air oven and dry for 1 hour. Then raise the temperature to 95°C and continue drying for 2 hours to remove the free water on the surface of the polyester chips and perform pre-crystallization. Then place them in a 100°C vacuum oven and dry for 1 hour. Then raise the temperature to 120°C and dry for 24 hours to remove the bound water inside the polyester chips and obtain pretreated polyester chips.

[0051] S2. The pretreated polyester chips and the modified nano-titanium dioxide prepared in Example 1 were mixed at a mass ratio of 1:0.18, and then melt-blended and granulated using a twin-screw extruder to obtain the modified polyester masterbatch.

[0052] S3. Using a melt spinning machine, the modified polyester masterbatch is extruded from the three-hole spinneret and wound up by a winding machine to obtain modified polyester fiber.

[0053] S4. Modified polyester fiber and ramie fiber are added to the opening machine at a mass ratio of 8:1.9 and loosened into cotton-like fibers. Simultaneously, they are mixed and impurities are removed during the loosening process. Then, the mixture is fed into the carding machine using a quantitative feeding method and a cross-laid web is formed to achieve a density of 125 g / m². 2 A fiber web with a surface density of 580 needles / cm² is formed, and then the fiber web is subjected to three needle punches. The first needle punching frequency is 520 r / min, the needle punching depth is 6 mm, and the needle punching density is 580 needles / cm². 2 The second acupuncture session had a frequency of 780 r / min, a depth of 8 mm, and a density of 700 needles / cm². 2 The third acupuncture point had a frequency of 920 r / min, a depth of 14 mm, and a density of 850 needles / cm². 2 A water-repellent and breathable nonwoven fabric was prepared.

[0054] Comparative Example 1: A method for preparing modified nano-titanium dioxide includes the following steps:

[0055] 5g of nano-titanium dioxide was ultrasonically dispersed in 90mL of anhydrous ethanol and 20mL of deionized water, and then 4.6g of quaternized cashew phenol derivative was added. The mixture was stirred at 70℃ for 12h. After the reaction was completed, the mixture was filtered, washed and dried to prepare modified nano-titanium dioxide.

[0056] The preparation method of quaternized cashew phenol derivatives includes the following steps:

[0057] (1) In a nitrogen atmosphere, 13 mL of sodium bicarbonate saturated aqueous solution was added dropwise to 13 mL of dichloromethane solution containing 1 g of cashew phenol. The solution was cooled to 0 °C in an ice-water bath. 0.86 g of m-chloroperoxybenzoic acid was added in batches over 30 min. After reacting for 30 min, dichloromethane, sodium bicarbonate saturated aqueous solution and sodium thiosulfate saturated aqueous solution were added for extraction to obtain the organic phase. The organic phase was then dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation. The solution was then purified by silica gel chromatography (V petroleum ether: V ethyl acetate = 8:1) to prepare epoxidized cashew phenol.

[0058] (2) Dissolve the prepared epoxidized cashew phenol in 10 mL of isopropanol and add it dropwise to a reaction system containing 1.5 g of 1,2-dibromoethane, 1.1 g of potassium carbonate and 25 mL of isopropanol. Reflux at 90 °C for 12 h. After the reaction is completed, the mixture is purified by filtration, rotary evaporation and column chromatography (V petroleum ether: V ethyl acetate = 10:1) to prepare bromoepoxidized cashew phenol ether.

[0059] (3) Take 1.2g of brominated epoxy cashew ether, 0.24g of N-methylimidazol and 20mL of acetonitrile solvent in a reactor, stir and mix, and react at 65℃ for 18h. After the reaction is completed, filter, rotary evaporate and column chromatography (V chloromethane: V methanol = 10:1) to prepare epoxy quaternized cashew ether.

[0060] (4) Take 2g of chitosan and add it to 100mL of 8wt% sodium hydroxide aqueous solution and 4wt% urea aqueous solution. After reacting at -20℃ for 36h, add 0.8g of epoxy quaternized cashew phenol and react at 0℃ for 12h. After neutralization with hydrochloric acid, dialyze with distilled water to prepare quaternized cashew phenol derivative.

[0061] Comparative Example 2: A method for preparing modified nano-titanium dioxide includes the following steps:

[0062] 5g of nano-titanium dioxide was ultrasonically dispersed in 90mL of anhydrous ethanol and 20mL of deionized water. Then, 4.6g of silicon-containing epoxy quaternized cashew phenol was added, and the mixture was stirred at 70℃ for 12h. After the reaction was completed, the mixture was filtered, washed, and dried to prepare modified nano-titanium dioxide.

[0063] The preparation method of quaternized cashew phenol containing silicon epoxy groups includes the following steps:

[0064] (1) Take 7.1g of γ-methacryloxypropyltrimethoxysilane, 5g of tetramethyldisiloxane and 50mL of toluene solvent in a reactor, introduce nitrogen gas, heat to 80℃ in an oil bath under magnetic stirring, then add 5mg of Wilkinson catalyst and react at a constant temperature for 6h. After the reaction is completed, remove the organic solvent by rotary evaporation, and purify the reaction solution by silica gel chromatography column (V hexane:V ethyl acetate = 2:1) to prepare the modified silane coupling agent;

[0065] (2) In a nitrogen atmosphere, 13 mL of sodium bicarbonate saturated aqueous solution was added dropwise to 13 mL of dichloromethane solution containing 1 g of cashew phenol. The solution was cooled to 0 °C in an ice-water bath. 0.86 g of m-chloroperoxybenzoic acid was added in batches over 30 min. After reacting for 30 min, dichloromethane, sodium bicarbonate saturated aqueous solution and sodium thiosulfate saturated aqueous solution were added for extraction to obtain the organic phase. The organic phase was then dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation. The solution was then purified by silica gel chromatography (V petroleum ether: V ethyl acetate = 8:1) to prepare epoxidized cashew phenol.

[0066] (3) Dissolve the prepared epoxidized cashew phenol in 10 mL of isopropanol and add it dropwise to a reaction system containing 1.5 g of 1,2-dibromoethane, 1.1 g of potassium carbonate and 25 mL of isopropanol. Reflux at 90 °C for 12 h. After the reaction is completed, the mixture is purified by filtration, rotary evaporation and column chromatography (V petroleum ether: V ethyl acetate = 10:1) to prepare bromoepoxidized cashew phenol ether.

[0067] (4) Take 1.2g of brominated epoxy cashew ether, 0.24g of N-methylimidazolium and 20mL of acetonitrile solvent in a reactor, stir and mix, and react at 65℃ for 18h. After the reaction is completed, filter, rotary evaporate and column chromatography (V chloromethane: V methanol = 10:1) to prepare epoxy quaternized cashew ether.

[0068] (5) Take 1g of epoxy quaternized cashew phenol and 0.76g of modified silane coupling agent into a reactor, then add caster catalyst (45ppm Pt content), stir and heat to 110℃ for 6h, then cool to 80℃, add 0.02g of activated carbon and continue to react for 1h. After the reaction is completed, filter and distill under reduced pressure to prepare silicon-containing epoxy quaternized cashew phenol.

[0069] Comparative Example 3: A method for preparing a water-repellent and breathable nonwoven fabric. Compared with Example 4, the modified nano-titanium dioxide prepared in Example 1 was replaced by an equal amount with the modified nano-titanium dioxide prepared in Comparative Example 1, and the remaining components and preparation methods were the same as in Example 4.

[0070] Comparative Example 4: A method for preparing a water-repellent and breathable nonwoven fabric. Compared with Example 4, the modified nano-titanium dioxide prepared in Example 1 is replaced by an equal amount of the modified nano-titanium dioxide prepared in Comparative Example 2, and the remaining components and preparation methods are the same as in Example 4.

[0071] Comparative Example 5: A method for preparing a water-repellent and breathable nonwoven fabric. Compared with Example 4, the modified nano-titanium dioxide prepared in Example 1 was replaced with an equal amount of nano-titanium dioxide, and the remaining components and preparation methods were the same as in Example 4.

[0072] Performance testing

[0073] The nonwoven fabrics prepared in Examples 2-4 and Comparative Examples 3-5 were subjected to performance testing:

[0074] (1) Mechanical property testing: The breaking strength and elongation at break were tested in accordance with GB / T 24218.3-2010, and the data results are shown in Table 1.

[0075] (2) High temperature resistance test: The sample was placed in an oven and heated to 100℃ at a rate of 2℃ / min and then kept at a constant temperature for 24h. The fracture strength of the sample before and after treatment was measured. The fracture strength retention rate was used as the evaluation of high temperature resistance. The data results are shown in Table 1.

[0076] (3) Abrasion resistance test: Abrasion resistance was tested using a YG(B)522 fabric abrasion tester, with a test area of ​​20 cm². 2 The number of friction cycles was set to 400, and the mass of the sample before and after friction was recorded. The wear resistance of the sample was characterized by the average wear per unit area, and the data results are shown in Table 1.

[0077] (4) Water repellency test: The water repellency level is in accordance with GB / T 4745-2012. The temperature is 20℃ and the relative humidity is 65%. Five samples of each type are tested, and the average value is taken. The data results are shown in Table 1.

[0078] (5) Antibacterial performance test: Antibacterial performance test was conducted in accordance with GB / T 20944.3-2008 standard. The test strains were Escherichia coli and Staphylococcus aureus. The data results are shown in Table 1.

[0079] Table 1 Sample performance test results

[0080]

[0081] As can be seen from the data in Table 1, the nonwoven fabrics prepared in Examples 2-4 of this invention possess good mechanical properties, high-temperature resistance, abrasion resistance, water repellency, and antibacterial properties. In Comparative Example 3, the modified nano-titanium dioxide added did not incorporate a modified silane coupling agent. Its measured mechanical properties, high-temperature breaking strength retention rate, abrasion resistance, water repellency rating, and antibacterial rate after washing were lower than those in Examples 2-4. This is because the absence of silanol groups that undergo dehydration condensation with the hydroxyl groups on the surface of nano-titanium dioxide resulted in the quaternized cashew phenol derivative not being firmly bonded to the surface of nano-titanium dioxide, thus reducing the long-term antibacterial performance compared to Examples 2-4. Simultaneously, it led to poorer interfacial compatibility between nano-titanium dioxide and the matrix material, further reducing mechanical properties. Furthermore, the lack of highly water-resistant, heat-resistant, and abrasion-resistant siloxane bonds on the surface of nano-titanium dioxide resulted in lower high-temperature resistance, abrasion resistance, and water repellency compared to Examples 2-4. Examples 2-4 show a decrease in antibacterial rate. In Comparative Example 4, the modified nano-titanium dioxide introduced with silicon-containing epoxy quaternized cashew phenol without chitosan showed a decrease in both measured antibacterial rate and antibacterial rate after washing compared to Examples 2-4. This indicates that chitosan grafting through strong chemical bonds is beneficial for improving the long-term antibacterial performance of nonwoven fabrics. In Comparative Example 5, the nano-titanium dioxide was not modified, and its overall performance showed the most significant decrease compared to Examples 2-4. This is because the aggregation of nano-titanium dioxide leads to a decrease in mechanical properties. Furthermore, the lack of grafting of the hydrophobic tails of long-chain alkanes and silicon-oxygen bonds in the silicon-containing quaternized cashew phenol derivatives reduces water repellency. Additionally, the lack of grafting of antibacterial quaternary ammonium salt cations and chitosan further reduces the antibacterial performance.

[0082] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0083] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A water-repellent and breathable nonwoven fabric, characterized in that, Made from modified polyester fiber and natural fiber needle punching, the modified polyester fiber is prepared by mixing polyester chips and modified nano titanium dioxide to form a modified polyester masterbatch, and then produced by melt spinning; the modified nano titanium dioxide is made by grafting silicon-containing quaternized cashew phenol derivatives onto the surface of nano titanium dioxide using a chemical reaction. The silicon-containing quaternized cashew phenol derivative is prepared by oxidizing cashew phenol to epoxidized cashew phenol with m-chloroperoxybenzoic acid, followed by a substitution reaction with 1,2-dibromoethane to obtain brominated epoxy cashew phenol ether. Then, N-methylimidazolium reacts with the brominated epoxy cashew phenol ether to prepare epoxy quaternized cashew phenol. A modified silane coupling agent is then used to react with the side chain of the epoxy quaternized cashew phenol via hydrosilylation. Subsequently, the prepared silicon-containing epoxy quaternized cashew phenol is reacted with chitosan via a ring-opening reaction. The modified silane coupling agent is prepared by reacting γ-methacryloyloxypropyltrimethoxysilane with tetramethyldisiloxane via hydrosilylation.

2. The water-repellent and breathable nonwoven fabric according to claim 1, characterized in that, The natural fiber is either cotton or linen; the mass ratio of the modified polyester fiber to the natural fiber is 8:1~2.

3. The water-repellent and breathable nonwoven fabric according to claim 1, characterized in that, The preparation method of the modified nano titanium dioxide includes the following steps: nano titanium dioxide is ultrasonically dispersed in anhydrous ethanol and deionized water, then a silicon-containing quaternized cashew phenol derivative is added, and the mixture is stirred and reacted at 60~85℃ for 10~12h. After the reaction is completed, the mixture is filtered, washed and dried to obtain modified nano titanium dioxide.

4. The water-repellent and breathable nonwoven fabric according to claim 3, characterized in that, The preparation method of the silicon-containing quaternized cashew phenol derivative includes the following steps: (1) Take γ-methacryloxypropyltrimethoxysilane, tetramethyldisiloxane and toluene solvent in a reactor, introduce nitrogen gas, heat in an oil bath to 75~85℃ under magnetic stirring, then add Wilkinson catalyst and react at a constant temperature for 5~7h. After the reaction is completed, remove the organic solvent by rotary evaporation, and purify the reaction solution by silica gel chromatography column to prepare the modified silane coupling agent. (2) In a nitrogen atmosphere, a saturated aqueous solution of sodium bicarbonate was added dropwise to a dichloromethane solution containing cashew phenol. The solution was cooled to 0-4°C in an ice-water bath. The m-chloroperoxybenzoic acid was added in batches over 30 min. After reacting for 25-40 min, dichloromethane, a saturated aqueous solution of sodium bicarbonate, and a saturated aqueous solution of sodium thiosulfate were added for extraction. The organic phase was then dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation. The solution was then purified by silica gel chromatography to prepare epoxidized cashew phenol. (3) Dissolve epoxidized cashew phenol in isopropanol and add it dropwise to a reaction system containing 1,2-dibromoethane, potassium carbonate and isopropanol. Reflux at 85~90℃ for 10~12h. After the reaction is completed, bromoepoxidized cashew phenol ether is prepared by filtration, rotary evaporation and column chromatography. (4) Take brominated epoxy cashew ether, N-methylimidazolium and acetonitrile solvent in a reactor, stir and mix, and then react at 60~75℃ for 16~20h. After the reaction is completed, filter, rotary evaporate and column chromatography are used to purify the product to prepare epoxy quaternized cashew ether. (5) Take epoxy-quaternized cashew phenol and modified silane coupling agent into a reactor, then add caster catalyst, stir and heat to 105~110℃ for 6~7h, then cool to 75~80℃, add activated carbon and continue the reaction for 0.5~1h, after the reaction is completed, filter and vacuum distill to prepare silicon-containing epoxy-quaternized cashew phenol; (6) Chitosan was added to 8wt% sodium hydroxide aqueous solution and 4wt% urea aqueous solution and reacted at -20℃ for 34~36h. Then, silicon-containing epoxy quaternized cashew phenol was added and reacted at 0~4℃ for 10~12h. After neutralization with hydrochloric acid, the mixture was dialyzed with distilled water to prepare silicon-containing quaternized cashew phenol derivative.

5. The water-repellent and breathable nonwoven fabric according to claim 4, characterized in that, The molar ratio of γ-methacryloxypropyltrimethoxysilane to tetramethyldisiloxane is 1:1 to 1.

3.

6. The water-repellent and breathable nonwoven fabric according to claim 4, characterized in that, The molar ratio of cashew phenol, m-chloroperoxybenzoic acid and 1,2-dibromoethane is 1:1.2~1.5:2.3~2.

5.

7. The water-repellent and breathable nonwoven fabric according to claim 4, characterized in that, The molar ratio of the brominated epoxy cashew phenolic ether to N-methylimidazole is 1:1 to 1.

1.

8. A method for preparing a water-repellent and breathable nonwoven fabric according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. The polyester chips are dried to remove the free water on the surface of the polyester chips and pre-crystallized. Then, the drying is continued to remove the bound water inside the polyester chips to obtain pre-treated polyester chips. S2. The pretreated polyester chips and modified nano-titanium dioxide are mixed and then melt-blended and granulated using a twin-screw extruder to obtain modified polyester masterbatch. S3. Using a melt spinning machine, the modified polyester masterbatch is extruded from the three-hole spinneret and wound up by a winding machine to obtain modified polyester fiber. S4. Modified polyester fiber and natural fiber are added to the opening machine and loosened into cotton-like fibers. During the loosening process, they are mixed and impurities are removed. Then, they are fed into the carding machine using a quantitative feeding method and cross-laid to form a fiber web with the required surface density. The fiber web is then needle-punched to prepare a water-repellent and breathable nonwoven fabric.

9. The method for preparing the water-repellent and breathable nonwoven fabric according to claim 8, characterized in that, The mass ratio of the pretreated polyester chips to the modified nano-titanium dioxide is 1:0.05~0.2.

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