Water-based super-hydrophobic finishing agent based on microemulsion in-situ synthesis as well as preparation method and application of water-based super-hydrophobic finishing agent

Abstract

The invention discloses a water-based super-hydrophobic finishing agent based on microemulsion in-situ synthesis as well as a preparation method and application of the water-based super-hydrophobic finishing agent. According to the method, octadecyl trichlorosilane, a surfactant and a cosurfactant firstly form an oil-phase mixture, then water is added to form an oil-in-water type microemulsion, finally standing and aging are performed, silane is subjected to in-situ hydrolysis in a microemulsion nanoreactor, and the water-based super-hydrophobic finishing agent is prepared through a one-step method. An organic solvent reaction medium is completely abandoned, and the process is simple and environment-friendly. The obtained finishing agent is uniform in particle and good in stability, can endow the polyester fiber fabric with a super-hydrophobic surface with a contact angle greater than 158 degrees and a rolling angle less than 4 degrees after being used for treating the polyester fiber fabric, is excellent in wear resistance and durability, and has a wide industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of functional finishing technology for textiles, specifically to a water-based finishing agent that can synthesize superhydrophobic nanoparticles in situ without the need for organic solvent reaction media, its preparation method, and its application in the preparation of superhydrophobic polyester fiber fabrics. Background Technology

[0002] Superhydrophobic fabrics have attracted much attention due to their excellent waterproof, stain-resistant, and self-cleaning properties. Constructing superhydrophobic surfaces requires both micro- and nano-rough structures and low surface energy materials. Long-chain alkylsilanes (such as octadecyltrichlorosilane, OTS) are commonly used low surface energy materials, but they react violently with water and are difficult to control directly in the aqueous phase.

[0003] Existing technologies, such as the dissertation "Development of Waterproof and Sewage-Resistant Finishing Agents and Their Application in Textiles" by Wang Yuhang of Tianjin University of Technology, disclose a method: first, OTS is dissolved in the organic solvent n-hexane, and then a mixture of dimethyl sulfoxide (DMSO) and water is added. The hydrolysis rate of OTS is controlled by the formation of hydrogen bonds between DMSO and water molecules, generating hydrophobic silicon-oxygen nanoparticles in the organic phase. Then, the generated particles are extracted from the organic phase, transferred and dispersed into the aqueous phase with the help of surfactants, and finally made into an aqueous finishing agent. The shortcomings of this method are: (1) It depends on organic solvents as reaction media: the core synthesis steps must be carried out in organic phases such as n-hexane, which fails to completely get rid of the dependence on volatile organic compounds (VOCs) and does not conform to the development trend of green chemistry. (2) The process is complicated: it requires two relatively independent steps, "organic phase synthesis" and "aqueous phase dispersion", which involves phase transfer process, which is cumbersome and not conducive to continuous industrial production. (3) Product stability risk: the post-transfer process may lead to particle agglomeration, affecting the storage stability of the finishing agent and the uniformity of film formation on the fabric.

[0004] Therefore, developing a method for preparing finishing agents that synthesizes superhydrophobic nanoparticles in one step in an aqueous phase has significant technical and economic value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to overcome these limitations and provide a novel method for preparing superhydrophobic finishing agents based on microemulsion technology. This method eliminates the need for organic solvent reaction media, enabling the direct and controllable synthesis of hydrophobic nanoparticles in an aqueous phase. The process is greatly simplified, and the resulting finishing agent exhibits excellent performance.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an aqueous superhydrophobic finishing agent based on in-situ synthesis of microemulsion, comprising the following steps:

[0008] S1. Mix octadecyltrichlorosilane (OTS), surfactant and co-surfactant to form a homogeneous oil phase mixture;

[0009] S2. Under continuous stirring, deionized water is slowly added to the oil phase mixture to form a transparent or semi-transparent oil-in-water (O / W) microemulsion;

[0010] S3. The microemulsion system is left to stand at room temperature to allow OTS to undergo hydrolysis and condensation reactions within the nanodroplets of the microemulsion, generating hydrophobic silicon-oxygen nanoparticles in situ and directly and stably dispersing them in the aqueous phase, thus obtaining the waterborne superhydrophobic finishing agent.

[0011] Preferably, in step S1, the surfactant is a nonionic surfactant, preferably at least one of fatty alcohol polyoxyethylene ether (AEO series) and alkylphenol polyoxyethylene ether (OP series), and most preferably AEO-9; the co-surfactant is a C4-C8 straight-chain alcohol, preferably n-butanol and n-pentanol, and most preferably n-butanol.

[0012] Preferably, in step S1, the mass ratio of the OTS, surfactant, and co-surfactant is 1:(1-5):(0.2-1.5).

[0013] Preferably, in step S2, the mass ratio of water to OTS is (20-100):1. The stirring speed is 1000-5000 rpm.

[0014] Preferably, in step S3, the settling and aging time is 12-48 hours.

[0015] Secondly, the present invention provides an aqueous superhydrophobic finishing agent prepared by the above method. The finishing agent is characterized in that its hydrophobic nanoparticles are generated in situ in a nanoreactor of an oil-in-water microemulsion, exhibiting uniform particle size distribution and system stability.

[0016] Thirdly, the present invention provides the application of the above-mentioned waterborne superhydrophobic finishing agent in the preparation of superhydrophobic textiles.

[0017] Fourthly, this invention provides a method for preparing a superhydrophobic polyester fiber fabric, comprising: immersing a clean polyester fiber fabric in the aforementioned water-based superhydrophobic finishing agent, removing it after thorough immersion, and drying and curing it at 60-100°C, or air-drying it at room temperature. The water-based superhydrophobic finishing agent, when used to treat the polyester fiber fabric, imparts a superhydrophobic surface with a contact angle greater than 158° and a roll-off angle less than 4°, and exhibits excellent wear resistance and durability.

[0018] In summary, the present invention has the following beneficial effects:

[0019] (1) Fundamental process innovation: Unlike existing technologies that react in the organic phase (n-hexane), this invention innovatively utilizes an oil-in-water (O / W) microemulsion as a "nanoreactor," completely shifting the reaction site from the organic phase to the aqueous phase. This not only completely eliminates organic solvents as the reaction medium, thus eliminating VOCs at the source, but also combines "synthesis" and "dispersion" into one, achieving one-step in-situ preparation and revolutionizing the process flow.

[0020] (2) Product performance is significantly improved:

[0021] Excellent superhydrophobic properties: Due to the template confinement effect of the microemulsion droplets, the in-situ generated silica nanoparticles are more uniform in size and narrower in distribution. When applied to polyester fabrics, they can create denser and more uniform micro-nano rough structures. Experiments show that the treated fabrics can achieve a water contact angle of over 158° and a roll-off angle as low as below 4°, demonstrating excellent performance.

[0022] Exceptional durability: The particles adhere more firmly to the fabric surface. After 500 Martindale abrasion tests, the modified fabric still maintains a contact angle of over 150°, demonstrating superior mechanical stability compared to conventional methods.

[0023] Excellent finishing agent stability: The particles generated in situ are stabilized in situ by surfactant molecules, and the resulting finishing agent shows no visible precipitation or stratification after standing for 30 days. Its storage stability is far superior to that of the comparative product that requires subsequent transfer.

[0024] (3) Significant advantages in industrial application: This method requires no special equipment and operates under mild conditions (room temperature reaction), making it very suitable for industrial scale-up production and providing a brand-new technical path for the preparation of high-performance, environmentally friendly superhydrophobic textiles. Detailed Implementation

[0025] The present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0026] Raw materials used: Octadecyltrichlorosilane (OTS), analytical grade; fatty alcohol polyoxyethylene ether (AEO-3, AEO-9), alkylphenol polyoxyethylene ether (OP-10), industrial grade; n-butanol, n-pentanol, n-octanol, analytical grade; polyester fiber woven fabric (specification: 75D / 72F, weight: 100g / m²). 2 ), commercially available.

[0027] Test method:

[0028] (1) Static contact angle / roll-off angle: Using a contact angle measuring instrument, the water droplet volume is 5μL, and 5 points are measured for each sample and the average value is taken.

[0029] (2) Abrasion resistance: Refer to GB / T 3920-2008 standard, use Martindale abrasion tester, pressure 9kPa, test 500 times and measure the contact angle.

[0030] (3) Storage stability: The finishing agent was sealed in a transparent glass bottle and left to stand at room temperature for 30 days to observe its condition.

[0031] Example 1

[0032] Preparation of waterborne superhydrophobic finishing agent: 1 g OTS, 1 g AEO-9 and 0.2 g n-butanol were mixed in a beaker and magnetically stirred for 10 minutes to form a homogeneous and transparent oil phase mixture. Under mechanical stirring at 1000 rpm, 20 g deionized water (mass ratio to OTS 20:1) was slowly added dropwise. After the addition was complete, the system was in a milky white microemulsion state. The resulting microemulsion was sealed and allowed to stand at room temperature for 12 hours to age, yielding finishing agent A1.

[0033] Preparation of superhydrophobic polyester fiber fabric: Polyester fabric (75D / 72F, 100g / m²) was prepared. 2 Wash and dry. Immerse the fabric in finishing agent A1 for 10 minutes, remove it and control the liquid retention rate to 80%, and finally air dry for 24 hours to obtain superhydrophobic fabric S1.

[0034] The performance test results are as follows:

[0035] Initial water contact angle: 155.2°

[0036] Initial roll angle: 6.5°

[0037] Contact angle after 500 abrasion cycles: 146.8°

[0038] Storage stability of finishing agent (30 days): There is slight sediment at the bottom, which can be redispersed after shaking.

[0039] Example 2

[0040] Preparation of waterborne superhydrophobic finishing agent: 1g OTS, 5g AEO-9 and 1.5g n-pentanol were mixed in a beaker and magnetically stirred for 10 minutes. 100g deionized water was slowly added dropwise while stirring at 5000rpm. A semi-transparent microemulsion was formed. The resulting microemulsion was sealed and allowed to stand at room temperature for 48 hours to obtain finishing agent A2.

[0041] Preparation of superhydrophobic polyester fiber fabric: Same as in Example 1, but using finishing agent A2 to obtain fabric S2.

[0042] The performance test results are as follows:

[0043] Initial water contact angle: 156.8°

[0044] Initial roll angle: 5.8°

[0045] Contact angle after 500 abrasion cycles: 148.5°

[0046] Storage stability of finishing agent (30 days): No obvious precipitation, but the system became slightly thicker.

[0047] Example 3

[0048] Preparation of water-based superhydrophobic finishing agent: 1g OTS, 3g OP-10 and 0.5g n-butanol were mixed in a beaker and magnetically stirred for 10 minutes. 50g deionized water was slowly added dropwise under mechanical stirring at 3000rpm. A homogeneous, semi-transparent microemulsion was formed. The resulting microemulsion was sealed and allowed to stand at room temperature for 24 hours to obtain finishing agent A3.

[0049] Preparation of superhydrophobic polyester fiber fabric: Same as in Example 1, but using finishing agent A3 to obtain fabric S3.

[0050] Performance test results:

[0051] Initial water contact angle: 157.5°

[0052] Initial roll angle: 5.0°

[0053] Contact angle after 500 abrasion cycles: 149.2°

[0054] Storage stability of finishing agent (30 days): homogeneous and stable, with no precipitation.

[0055] Example 4

[0056] Preparation of waterborne superhydrophobic finishing agent: 1g OTS, 3g AEO-3 and 0.5g n-octanol were mixed in a beaker and magnetically stirred for 10 minutes. 50g deionized water was slowly added dropwise under mechanical stirring at 3000rpm. A microemulsion was formed, but its transparency was slightly worse than the system using n-butanol. The resulting microemulsion was sealed and aged at room temperature for 24 hours to obtain finishing agent A4.

[0057] Preparation of superhydrophobic polyester fiber fabric: Same as in Example 1, but using finishing agent A4 to obtain fabric S4.

[0058] Performance test results:

[0059] Initial water contact angle: 156.0°

[0060] Initial roll angle: 6.2°

[0061] Contact angle after 500 abrasion cycles: 147.5°

[0062] Storage stability of finishing agent (30 days): slight stratification, which can be restored by shaking.

[0063] Example 5

[0064] Preparation of waterborne superhydrophobic finishing agent: 1g OTS, 3g AEO-9 and 0.5g n-butanol were mixed in a beaker and magnetically stirred for 10 minutes to form a homogeneous and transparent oil phase mixture. 50g deionized water was slowly added dropwise under mechanical stirring at 3000rpm. A homogeneous, highly transparent and well-flowing microemulsion was formed. The resulting microemulsion was sealed and aged at room temperature for 24 hours to obtain finishing agent A5.

[0065] Preparation of superhydrophobic polyester fiber fabric: Same as in Example 1, but using finishing agent A5 to obtain fabric S5.

[0066] Performance test results:

[0067] Initial water contact angle: 158.5°

[0068] Initial roll angle: 3.2°

[0069] Contact angle after 500 abrasion cycles: 152.8°

[0070] Storage stability of finishing agent (30 days): Uniform and stable, with no precipitation, layering or thickening.

[0071] Comparative Example 1 (Organic Phase Method)

[0072] Preparation of the finishing agent: Following the preparation method described in the literature: Place 10 ml of n-hexane into a 50 ml centrifuge tube, add 1 ml of OTS and shake well. Add 0.1 ml of a DMSO:water mixture of 4:1, vortex for 1 min, sonicate for 1 min, and let stand overnight. Use a pipette to pipette 2 ml of the hydrolysis product into a centrifuge tube containing 20 ml of deionized water and 0.15 ml of AEO-9, vortex for 30 seconds to obtain finishing agent D1. This process involves organic solvents and is a two-step method.

[0073] Fabric preparation: Same as in Example 1, but using finishing agent D1 to obtain fabric DS1.

[0074] Performance test results:

[0075] Initial water contact angle: 143.3°

[0076] Initial roll angle: 10.2°

[0077] Contact angle after 500 abrasion cycles: 113.5°

[0078] Storage stability of finishing agent (30 days): obvious stratification, with hard sediment at the bottom that is difficult to redisperse.

[0079] Process evaluation: The process is complex and uses the flammable organic solvent n-hexane, posing safety and environmental risks.

[0080] Comparative Example 2

[0081] Preparation of the finishing agent: 1g OTS, 3g sodium dodecyl sulfate (SDS, an ionic surfactant), and 0.5g n-butanol were mixed. While stirring at 3000rpm, 50g deionized water was added dropwise. The system failed to form a microemulsion, presenting as a rough, uneven emulsion that rapidly separated into layers upon standing. The upper emulsion was forcibly used to treat the fabric, yielding fabric DS2.

[0082] Due to the instability of the finishing agent, the fabric could not be treated evenly. Performance testing:

[0083] Initial water contact angle: 140.8° (hydrophobicity significantly reduced)

[0084] Initial roll angle: >15° (severe water droplet adhesion)

[0085] Finishing agent state: It is unstable after preparation and separates into layers.

[0086] Comparative Example 3

[0087] Preparation of the finishing agent: 1g OTS and 3g AEO-9 were mixed without adding any co-surfactant. 50g of deionized water was added dropwise while stirring at 3000rpm. The system was very viscous, forming a heterogeneous emulsion that rapidly separated into layers upon standing. After aging for 24 hours, the finishing agent showed significant aggregation and precipitation.

[0088] The upper emulsion was forcibly used to treat the fabric, resulting in fabric DS3. Performance testing:

[0089] Initial water contact angle: 142.5°

[0090] Initial roll angle: >10°

[0091] Finishing agent status: Completely separates within 1 hour after preparation and cannot be stored.

[0092] Conclusion Analysis:

[0093] Examples 1-5 vs. Comparative Example 1: These examples demonstrate the fundamental advantages of the all-aqueous one-step method of this invention compared to the existing organic two-step method. All examples of this invention are significantly superior to Comparative Example 1 in terms of environmental friendliness, process simplicity, finishing agent storage stability, and fabric durability. This indicates that the microemulsion in-situ synthesis technology brings unexpected technical benefits.

[0094] Example 5 vs. other examples: This demonstrates that AEO-9 and n-butanol are the optimal combination. Example 5 showed the best performance in terms of microemulsion transparency, fabric superhydrophobicity (high contact angle, low roll-off angle), abrasion resistance, and long-term stability of the finishing agent.

[0095] Example 5 vs. Comparative Examples 2 & 3: This demonstrates that the correct selection and synergistic effect of surfactants and co-surfactants are crucial for forming stable and efficient microemulsion systems. Comparative Examples 2 and 3, in particular, resulted in the collapse of the microemulsion system and ultimately inferior product performance.

[0096] Conclusion: The test data fully demonstrate that the present invention, through its unique microemulsion in-situ synthesis technology, not only achieves a green and simplified breakthrough in the process, but also achieves unexpected and significant improvements in the hydrophobic properties and durability of the final product.

Claims

1. A method for preparing an aqueous superhydrophobic finishing agent based on in-situ synthesis of microemulsion, characterized in that, Includes the following steps: S1. Mix octadecyltrichlorosilane, a surfactant, and a co-surfactant to form an oil phase mixture; S2. Under stirring, deionized water is added to the oil phase mixture to form an oil-in-water microemulsion; S3. Allow the microemulsion to stand and age, allowing octadecyltrichlorosilane to hydrolyze and condense in situ within the microemulsion droplets, directly obtaining an aqueous superhydrophobic finishing agent.

2. The method according to claim 1, characterized in that: In step S1, the surfactant is a nonionic surfactant, preferably at least one of fatty alcohol polyoxyethylene ether (AEO series) and alkylphenol polyoxyethylene ether (OP series), and most preferably AEO-9; the co-surfactant is a C4-C8 straight-chain alcohol, preferably n-butanol and n-pentanol, and most preferably n-butanol.

3. The method according to claim 1, characterized in that: In step S1, the mass ratio of the octadecyltrichlorosilane, surfactant, and co-surfactant is 1:(1-5):(0.2-1.5).

4. The method according to claim 1, characterized in that: In step S2, the mass ratio of deionized water to octadecyltrichlorosilane is (20-100):

1.

5. The method according to claim 1, characterized in that: In step S3, the settling and aging time is 12-48 hours.

6. A method for preparing a superhydrophobic polyester fiber fabric, characterized in that, include: The polyester fiber fabric is immersed in the water-based superhydrophobic finishing agent described in claim 1, and then dried to obtain the final product.

7. The method according to claim 6, characterized in that: The water-based superhydrophobic finishing agent, when used to treat polyester fiber fabrics, can impart a superhydrophobic surface with a contact angle greater than 158° and a roll-off angle less than 4°, and exhibits excellent wear resistance and durability.