A fluorine-free waterproof textile finishing agent and its preparation method

Abstract

This invention proposes a fluorine-free waterproof textile finishing agent and its preparation method, belonging to the field of textile auxiliaries technology. The method involves fine emulsion polymerization, using acrylate monomers as the core, and utilizing tetraethyl orthosilicate under alkaline conditions to form nano-SiO2 embedded on the surface of microspheres, constructing a micro-nano rough structure. Further modification with a compound of epoxy-containing silanes and hydrophobic silanes imparts a fully hydrophobic surface to the microspheres and enhances their reactivity with fabric fibers. The resulting finishing agent imparts excellent waterproof performance and superior wash fastness to textiles, and the process is simple, environmentally friendly, and fluorine-free, meeting the market demand for high-end functional textiles.

Description

Technical Field

[0001] This invention relates to the field of textile auxiliaries technology, specifically to a fluorine-free waterproof textile finishing agent and its preparation method. Background Technology

[0002] With increasing environmental awareness and stricter global restrictions on hazardous chemicals, the textile industry will place greater emphasis on the functionality and effective environmental protection of fabrics, particularly in outdoor clothing, sportswear, and home textiles, where water resistance is crucial. Traditional fluorinated waterproofing agents typically contain perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), both long-chain fluorocarbons. These chemicals are extremely stable and form a hydrophobic coating on fabric surfaces, resulting in excellent water resistance. However, fluorinated compounds are bioaccumulative and environmentally persistent, meaning they are not easily degraded in the environment. Therefore, these substances accumulate along the food chain, posing potential risks to the immune system and increasing carcinogenic hazards.

[0003] In recent years, with increasingly stringent global environmental regulations, the research and development of fluorine-free waterproofing agents has become a hot topic in the industry. Currently, fluorine-free waterproofing agents mainly include three categories: silicone, polyurethane, and acrylate. Among them, polyacrylate waterproofing agents hold an irreplaceable position in the market due to their advantages such as soft film, good extensibility, strong adhesion, excellent weather resistance, and non-toxicity. For example, Chinese invention patent CN116043547A discloses an acrylate-based fluorine-free waterproofing agent, which has excellent waterproofing and durability. However, its main polymer component needs to be obtained from five functional monomers through RAFT polymerization, making the process relatively complex. Therefore, developing fluorine-free waterproofing agents with simple processes and long-lasting waterproofing effects has become an urgent need in the industry. Summary of the Invention

[0004] To overcome the aforementioned problems in the prior art, this invention proposes a fluorine-free waterproof textile finishing agent and its preparation method. This invention uses acrylate monomers as the core, utilizing tetraethyl orthosilicate in a sol-gel reaction under alkaline conditions to form nano-SiO2 embedded on the surface of microspheres, constructing a micro-nano rough structure. Further modification with a compound of epoxy-containing silanes and hydrophobic silanes imparts a fully hydrophobic surface to the microspheres and enhances their reactivity with fabric fibers, enabling the polyacrylate waterproofing agent to possess both excellent waterproof and wash-resistant properties.

[0005] The technical solution of this invention is implemented as follows: This invention provides a method for preparing a fluorine-free waterproof textile finishing agent, comprising the following steps: S1. An emulsifier is dissolved in water to obtain an aqueous phase. Acrylic monomer A, acrylate monomer B, a crosslinking agent, an initiator, tetraethyl orthosilicate, and a double-bonded silane are mixed and added as an oil phase. The mixture is first pre-emulsified by high-speed shearing, and then ultrasonically emulsified to obtain an emulsion. The acrylate monomer A is selected from one of n-butyl acrylate, isobutyl acrylate, and tert-butyl acrylate. The acrylate monomer B is selected from one of octadecyl acrylate, tridecyl acrylate, dodecyl acrylate, and lauryl acrylate. S2. Add ammonia to adjust the pH of the aqueous phase to 10-11, stir at room temperature for a period of time; then heat and stir the reaction, centrifuge, wash, and dry to obtain dry powder; S3. Disperse the dry powder in ethanol, add silane coupling agents a and b, stir to react, centrifuge and wash, and dry to obtain a fluorine-free waterproof textile finishing agent.

[0006] In this invention, acrylate monomer A is selected from soft monomers such as n-butyl acrylate to ensure that the textile does not lose its flexibility after waterproofing. Acrylate monomer B is selected from hydrophobic monomers such as octadecyl acrylate to impart excellent hydrophobic properties to the textile. Adjusting the pH of the aqueous phase to 10-11 with ammonia is to induce tetraethyl orthosilicate to rapidly undergo a sol-gel reaction at the emulsion interface, ultimately forming nanoscale protrusions on the surface of polyacrylate microspheres.

[0007] As a further improvement of the present invention, in step S1, the emulsifier is a mixture of emulsifier a and emulsifier b. Emulsifier a is selected from sodium dodecyl sulfate and sodium dodecylbenzene sulfonate, and emulsifier b is selected from fatty alcohol polyoxyethylene ether-7, fatty alcohol polyoxyethylene ether-9, and isomeric tridecyl alcohol polyoxyethylene ether-10. The mass ratio of emulsifier a to b is 1:(0.5-1). The total amount of emulsifier is 1-3 wt% of the total mass of acrylate monomer A and acrylate monomer B.

[0008] In the technical solution of this invention, two emulsifiers are used in combination to obtain a fine emulsion, ensuring that the final polyacrylate microsphere waterproof finishing agent has a particle size of about 100-500nm, which can better combine with the fabric fibers, while not reducing the hand feel of the fabric.

[0009] As a further improvement of the present invention, in step S1, the crosslinking agent is selected from one of ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3-butanediol diacrylate; the initiator is an oil-soluble initiator selected from one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, benzoyl peroxide, and dilauryl peroxide.

[0010] As a further improvement of the present invention, in step S1, the double-bonded silane is selected from one of vinyltrimethoxysilane, vinyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, and 3-(methacryloyloxy)propyltriethoxysilane.

[0011] In the technical solution of this invention, double-bonded silanes can form chemical bonds between silica nanoparticles and acrylate main polymers, ensuring that the nano-protrusion structure formed after the fabric is waterproofed will not fall off after multiple washes.

[0012] As a further improvement of the present invention, in step S1, the mass ratio of the aqueous phase to the oil phase is 100:(20-30).

[0013] As a further improvement of the present invention, in step S1, the mass ratio of acrylate monomer A, acrylate monomer B, crosslinking agent, initiator, tetraethyl orthosilicate, and double bond silane is 10:(9-11):(2-3):(0.1-0.2):(0.8-1.2):(0.3-0.5).

[0014] In this invention, the amount of tetraethyl orthosilicate used is relatively small compared to acrylate monomers. This is to allow it to form nano-SiO2 particles on the surface of the microspheres, rather than forming a continuous SiO2 shell covering the surface of the polyacrylate microspheres. The use of a crosslinking agent can impart good structural stability to the polyacrylate microspheres during the waterproof finishing heat treatment process.

[0015] As a further improvement of the present invention, in step S1, the high-speed shearing is shearing at 12000-20000 rpm for 5-10 min, and the ultrasonic emulsification is ultrasonic treatment at 200-600 W power for 10-20 min.

[0016] In the technical solution of this invention, high-speed shearing and ultrasonic emulsification are also used to obtain stable fine emulsions.

[0017] As a further improvement of the present invention, in step S2, the room temperature stirring reaction time is 2-4 hours, the heating stirring reaction temperature is 60-80°C, and the reaction time is 6-12 hours.

[0018] In the technical solution of this invention, the room temperature reaction is to enable tetraethyl orthosilicate to form nano-SiO2 particles through sol-gel reaction at the emulsion interface, and the temperature is raised to 60-80℃ to initiate the polymerization reaction of acrylate monomers.

[0019] As a further improvement of the present invention, in step S3, the mass ratio of the dry powder, silane coupling agent a, silane coupling agent b, and ethanol is 1:(0.5-1):(0.5-1):(20-40), the stirring reaction time is 4-8h, the silane coupling agent a is selected from one of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane, and the silane coupling agent b is selected from one of n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, n-octadecyltrimethoxysilane, and n-octadecyltriethoxysilane.

[0020] In the technical solution of this invention, silane coupling agent a is used to introduce epoxy groups on the surface of nano-SiO2 particles. The epoxy groups can react with active groups such as hydroxyl groups on the surface of fabrics such as cotton and linen to form chemical bonds. Silane coupling agent b is used to impart hydrophobic properties to the surface of nano-SiO2 particles, thereby further improving the overall hydrophobicity of the prepared textile finishing agent.

[0021] This invention further protects a fluorine-free waterproof textile finishing agent prepared by the above-described preparation method.

[0022] The present invention has the following beneficial effects: 1. This invention first obtains a fine emulsion by selecting a suitable emulsifier and emulsification conditions. Then, at room temperature, ammonia water is used to rapidly induce tetraethyl orthosilicate to quickly sol-gel at the emulsion droplet interface to form nano-silica particles. Due to the use of double-bonded silane, the nano-silica particles can form chemical bonds with the acrylate microspheres. At the same time, the Pickering effect of the nano-silica particles will also induce them to anchor at the emulsion droplet interface, and finally embed them on the surface of the acrylate microspheres to form a micro-nano hydrophobic structure similar to a lotus leaf.

[0023] 2. The surface of the acrylate microspheres prepared in step S2 still has a large number of silanol groups due to the presence of nano-silica particles, so the surface remains a patch structure of hydrophilic and hydrophobic properties. After modification with silane coupling agent b such as n-octadecyltrimethoxysilane in step S3, the surface of the microspheres can be endowed with fully hydrophobic properties. Silane coupling agent a is selected from silane coupling agents containing epoxy groups, which can react with active groups such as hydroxyl groups on the surface of fabrics such as cotton and linen to form chemical bonds.

[0024] 3. The prepared polyacrylate microsphere waterproofing agent can give textiles excellent waterproof performance and excellent wash fastness. It can maintain a stable hydrophobic effect after multiple washes and firmly adhere to the fiber surface without falling off, which fully meets the market demand for high-end functional textiles. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a SEM image of the waterproof textile finishing agent prepared in Example 1 of the present invention.

[0027] Figure 2 This is a SEM image of the waterproof textile finishing agent prepared in Comparative Example 2 of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1 This embodiment provides a method for preparing a fluorine-free waterproof textile finishing agent, including the following steps: S1. Dissolve 0.2g of emulsifier a (sodium dodecyl sulfate) and 0.2g of emulsifier b (fatty alcohol polyoxyethylene ether-7) in 100g of water to obtain an aqueous phase. Add 10g of n-butyl acrylate, 10g of octadecyl acrylate, 2.5g of crosslinking agent (ethylene glycol diacrylate), 0.2g of initiator (azobisisobutyronitrile), 1g of tetraethyl orthosilicate, and 0.4g of 3-(methacryloyloxy)propyltrimethoxysilane as an oil phase. First, pre-emulsify at 12000rpm for 10min, then sonicate at 600w for 10min to obtain an emulsion. S2. Add ammonia to adjust the pH of the aqueous phase to 11, stir at room temperature for 2 hours; then heat to 80°C and stir for 6 hours, centrifuge, wash, and dry to obtain dry powder; S3. Disperse 5g of the dry powder in 200g of ethanol, add 2.5g of 3-glycidyl etheroxypropyltrimethoxysilane and 2.5g of phenyltrimethoxysilane, stir at room temperature for 8h, centrifuge, wash, and dry to obtain a fluorine-free waterproof textile finishing agent.

[0030] from Figure 1 The SEM images clearly show that the overall particle size of the prepared textile finishing agent microspheres is approximately between 100-500 nm, and there are many nanoparticles on the surface.

[0031] Comparative Example 1: The only difference between this comparative example and Example 1 is that 3-(methacryloyloxy)propyltrimethoxysilane is not added in step S1.

[0032] Comparative Example 2: The only difference between this comparative example and Example 1 is that ammonia is not added in step S2 to adjust the pH. From Figure 2 The SEM image shows that the surface of the prepared textile finishing agent microspheres is very smooth.

[0033] Comparative Example 3: The only difference between this comparative example and Example 1 is that step S3 is not performed.

[0034] Comparative Example 4: The only difference between this comparative example and Example 1 is that 3-glycidoxypropyltrimethoxysilane is not added in step S3.

[0035] Comparative Example 5: The only difference between this comparative example and Example 1 is that phenyltrimethoxysilane is not added in step S3.

[0036] Example 2 This embodiment provides a method for preparing a fluorine-free waterproof textile finishing agent, including the following steps: S1. Dissolve 0.1g of emulsifier a (sodium dodecyl sulfate) and 0.1g of emulsifier b (fatty alcohol polyoxyethylene ether-9) in 100g of water to obtain an aqueous phase. Add 10g of n-butyl acrylate, 9g of octadecyl acrylate, 2g of crosslinking agent ethylene glycol diacrylate, 0.2g of initiator azobisisobutyronitrile, 0.8g of tetraethyl orthosilicate, and 0.3g of 3-(methacryloyloxy)propyltrimethoxysilane as an oil phase. First, pre-emulsify at 20000rpm for 5min, then sonicate at 200w for 20min to obtain an emulsion. S2. Add ammonia to adjust the pH of the aqueous phase to 11, stir at room temperature for 2 hours; then heat to 60°C and stir for 12 hours, centrifuge, wash, and dry to obtain dry powder; S3. Disperse 5g of the dry powder in 200g of ethanol, add 2.5g of 3-glycidyl etheroxypropyltrimethoxysilane and 2.5g of phenyltrimethoxysilane, stir at room temperature for 4h, centrifuge, wash, and dry to obtain a fluorine-free waterproof textile finishing agent.

[0037] Example 3 This embodiment provides a method for preparing a fluorine-free waterproof textile finishing agent, including the following steps: S1. Dissolve 0.3g of emulsifier a (sodium dodecyl sulfate) and 0.3g of emulsifier b (fatty alcohol polyoxyethylene ether-9) in 100g of water to obtain an aqueous phase. Add 10g of n-butyl acrylate, 11g of octadecyl acrylate, 3g of crosslinking agent (ethylene glycol diacrylate), 0.2g of initiator (azobisisobutyronitrile), 1.2g of tetraethyl orthosilicate, and 0.5g of 3-(methacryloyloxy)propyltrimethoxysilane as an oil phase. First, pre-emulsify at 15000rpm for 8min, then sonicate at 600w for 10min to obtain an emulsion. S2. Add ammonia to adjust the pH of the aqueous phase to 10, stir at room temperature for 4 hours; then heat to 80℃ and stir for 6 hours, centrifuge, wash, and dry to obtain dry powder; S3. Disperse 5g of the dry powder in 200g of ethanol, add 2.5g of 3-glycidyloxypropyltriethoxysilane and 2.5g of phenyltriethoxysilane, stir at room temperature for 4h, centrifuge, wash, and dry to obtain a fluorine-free waterproof textile finishing agent.

[0038] Performance testing: The fluorine-free waterproof textile finishing agent prepared in this invention was dispersed in acetone to obtain a 30wt% dispersion. Pure cotton bleached twill fabric was immersed in the dispersion for 20 minutes, then dipped and rubbed twice, dried at 80℃ for 5 minutes, and baked at 160℃ for 3 minutes to obtain a waterproof finished fabric. Performance tests were then conducted.

[0039] Test Example 1: Waterproofing Test The waterproof performance test follows the national standard GB / T 4745-2012. The specific method is as follows: Cut an 18×18cm sample, clamp it firmly, and install it on a fixed base at a 45° angle to the horizontal. Quickly and steadily pour 250mL (20±2℃) distilled or deionized water into the funnel. Spray the sample evenly and continuously towards the center of the sample through a nozzle at a distance from the center of the sample for 25-30 seconds. After spraying, quickly remove the clamp, turn the sample face down to a horizontal position, and gently tap it twice. Observe the degree of wetting of the sample. Then, evaluate its grade using a written description and comparison with pictures, and take the average of three measurements.

[0040] The rating criteria are as follows: Grade 0 – The entire sample surface is completely wetted.

[0041] Level 1 – The surface to be sprayed is completely wetted.

[0042] Level 1-2 – The sample surface is wetted beyond the spray point, and the wetted area exceeds half of the sprayed surface.

[0043] Level 2 – The sample surface is wetted beyond the spray point, and the wetted area is approximately half of the sprayed surface.

[0044] Level 2-3 – The sample surface is wetted beyond the spray point, and the wetted area is less than half of the sprayed surface.

[0045] Level 3 – Wetting at the spray point on the sample surface.

[0046] Grade 3-4 – The sample surface is wetted at half or less than half of the spray points.

[0047] Level 4 – The sample surface is partially wetted by sporadic spraying points.

[0048] Level 4-5 – The sample surface is not wetted, but there are a few water droplets.

[0049] Level 5 – No water droplets or wetting on the sample surface.

[0050] Washability is assessed by subjecting the treated textiles to 15 standard washes and then examining their water resistance.

[0051] The test results are shown in Table 1 below.

[0052] Table 1:

[0053] Test Example 2: Contact Angle Test To obtain more quantitative test results, 5 µL of water was dropped onto the fabric surface and analyzed using a KRÜSS DSA100 contact angle meter. The test results are shown in Table 2 below. The water contact angle of the original cotton fabric was 0°.

[0054] Table 2:

[0055] The test results above show that the fluorine-free waterproof textile finishing agents prepared in Examples 1-3 of this invention all have excellent waterproof effect and durability.

[0056] The only difference between Comparative Example 1 and Example 1 is that 3-(methacryloyloxy)propyltrimethoxysilane is not added in step S1. Due to the lack of chemical bond between the nano-sized hydrophobic SiO2 particles and the polyacrylate microsphere body, the waterproof effect is reduced after multiple washes. However, due to the Pickering effect, some nano-SiO2 particles are still embedded on the surface of the microspheres, so the decrease in waterproof effect after water washing is not too great.

[0057] The only difference between Comparative Example 2 and Example 1 is that ammonia was not added in step S2 to adjust the pH. Since the pH of the aqueous phase was not adjusted, tetraethyl orthosilicate could not be rapidly hydrolyzed at the emulsion droplet interface to form SiO2 particles. The prepared polyacrylate microspheres lacked nanoscale hydrophobic SiO2 particle structure, so the waterproof effect was relatively poor. At the same time, the surface of the microspheres was mainly polyacrylate. The epoxy silane coupling agent in step S3 had a low grafting rate and lacked chemical bond connection, which greatly reduced the waterproof effect after multiple washes.

[0058] The only difference between Comparative Example 3 and Example 1 is that step S3 is omitted. The surface of the prepared polyacrylate microspheres has a hydrophobic-hydrophilic patch structure, resulting in a relatively poor initial waterproof effect. At the same time, it lacks epoxy functional groups that can react with the fabric. After multiple washes, the polyacrylate microsphere textile finishing agent is completely removed from the fabric surface, causing the waterproof effect of the fabric to return to the state before the waterproof treatment.

[0059] The only difference between Comparative Example 4 and Example 1 is that 3-glycidyl etheroxypropyltrimethoxysilane is not added in step S3. The polyacrylate microsphere textile finishing agent prepared in this comparative example also has a micro-nano-scale hydrophobic structure, so the initial waterproof effect is comparable to that of the textile finishing agent prepared in Example 1. However, due to the lack of epoxy groups, the waterproof effect deteriorates sharply after multiple washes.

[0060] The only difference between Comparative Example 5 and Example 1 is that phenyltrimethoxysilane is not added in step S3. Although the introduction of epoxy groups on the surface of SiO2 particles can improve the durability of the waterproof effect, the surface of SiO2 particles remains hydrophilic after modification by the epoxy-containing silane coupling agent. Therefore, the overall polyacrylate microsphere textile finishing agent still has a hydrophobic-hydrophilic patch structure, and its waterproof effect is worse than that of the textile finishing agent prepared in Example 1.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a fluorine-free waterproof textile finishing agent, characterized in that, Includes the following steps: S1. An emulsifier is dissolved in water to obtain an aqueous phase. Acrylic monomer A, acrylate monomer B, a crosslinking agent, an initiator, tetraethyl orthosilicate, and a double-bonded silane are mixed and added as an oil phase. The mixture is first pre-emulsified by high-speed shearing, and then ultrasonically emulsified to obtain an emulsion. The acrylate monomer A is selected from one of n-butyl acrylate, isobutyl acrylate, and tert-butyl acrylate. The acrylate monomer B is selected from one of octadecyl acrylate, tridecyl acrylate, dodecyl acrylate, and lauryl acrylate. S2. Add ammonia to adjust the pH of the aqueous phase to 10-11, stir at room temperature for a period of time; then heat and stir the reaction, centrifuge, wash, and dry to obtain dry powder; S3. Disperse the dry powder in ethanol, add silane coupling agents a and b, stir to react, centrifuge and wash, and dry to obtain a fluorine-free waterproof textile finishing agent.

2. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S1, the emulsifier is a mixture of emulsifier a and emulsifier b. Emulsifier a is selected from sodium dodecyl sulfate and sodium dodecylbenzene sulfonate, and emulsifier b is selected from fatty alcohol polyoxyethylene ether-7, fatty alcohol polyoxyethylene ether-9, and isomeric tridecyl alcohol polyoxyethylene ether-10. The mass ratio of emulsifier a to b is 1:(0.5-1). The total amount of emulsifier is 1-3 wt% of the total mass of acrylate monomer A and acrylate monomer B.

3. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S1, the crosslinking agent is selected from one of ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3-butanediol diacrylate; the initiator is an oil-soluble initiator selected from one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, benzoyl peroxide, and dilauryl peroxide.

4. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S1, the double-bonded silane is selected from one of vinyltrimethoxysilane, vinyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, and 3-(methacryloyloxy)propyltriethoxysilane.

5. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S1, the mass ratio of the aqueous phase to the oil phase is 100:(20-30).

6. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S1, the mass ratio of acrylate monomer A, acrylate monomer B, crosslinking agent, initiator, tetraethyl orthosilicate, and double bond silane is 10:(9-11):(2-3):(0.1-0.2):(0.8-1.2):(0.3-0.5).

7. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S1, the high-speed shearing is shearing at 12000-20000 rpm for 5-10 minutes, and the ultrasonic emulsification is ultrasonic treatment at 200-600 W power for 10-20 minutes.

8. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S2, the room temperature stirring reaction time is 2-4 hours, and the heating stirring reaction temperature is 60-80°C, with a reaction time of 6-12 hours.

9. The method for preparing the fluorine-free waterproof textile finishing agent according to claim 1, characterized in that, In step S3, the mass ratio of the dry powder, silane coupling agent a, silane coupling agent b, and ethanol is 1:(0.5-1):(0.5-1):(20-40), the stirring reaction time is 4-8 hours, the silane coupling agent a is selected from one of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane, and the silane coupling agent b is selected from one of n-octyltrimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, n-octadecyltrimethoxysilane, and n-octadecyltriethoxysilane.

10. A fluorine-free waterproof textile finishing agent prepared by the preparation method according to any one of claims 1-9.

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