Preparation method of antifouling oil-repellent moisture-permeable cotton fiber and fabric applying same

Abstract

The invention discloses a preparation method of antifouling, oil-repellent and moisture-permeable cotton fibers and a fabric using the same, and relates to the technical field of fiber surface functionalization treatment. The method comprises the five steps of enzyme dewaxing, weak acid neutralization, perfluorosilane vapor deposition, thermocuring and moisture regaining and humidifying. The method comprises the following steps: firstly, mildly removing waxiness on the surface of the cotton fiber under the buffering of glycine and the assistance of ultrasonic waves by adopting the synergistic effect of lipase and acid cutting enzyme, and controlling the waxiness loss rate to be 0.8-1.2 wt%; then neutralizing the surface of the fiber through a weak acid bath containing citric acid and a silane coupling agent, and controlling the moisture content in cooperation with hot air drying. Carrying out perfluorodecyl / perfluorooctylsilane vapor deposition on the humidified fibers at low pressure, and introducing a trace amount of water vapor to induce Si-O-Si network construction; and the compactness and durability of the coating are further improved through two-stage thermocuring. The obtained fiber has high oil and water repellency and excellent moisture permeability.

Description

Technical Field

[0001] The present invention relates to the technical field of cotton fiber preparation, in particular to a method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber and a fabric using the same. Background Art

[0002] Cotton fibers naturally contain wax, pectin, and small amounts of lipid impurities. These non-cellulose components not only weaken the fabric's hydrophilicity but also easily bind to sebum and dust, leading to secondary oil adsorption during wear and washing. Hot alkali scouring is commonly used industrially to remove wax and improve hydrophilicity, but this method results in weight loss, reduced fiber strength, and the discharge of high chemical oxygen demand (COD) wastewater, creating both environmental and energy challenges.

[0003] Secondly, to impart water and oil repellency to fabrics, traditional finishing often involves padding with perfluorocarbon resins, fluorinated propylene polymers, or silane-modified emulsions, followed by curing by baking at temperatures above 150°C. While this can achieve water repellency ratings ≥5 and oil repellency ratings ≥3, long-chain perfluorochemicals are susceptible to degradation into persistent pollutants during washing and wastewater treatment. Furthermore, these treatments significantly reduce the fabric's water vapor transmission rate in high-humidity environments, exacerbating the feeling of stuffiness when worn.

[0004] Therefore, the industry is in urgent need of a functional cotton fiber that is mild, environmentally friendly, and can maintain good anti-fouling and oil repellency and moisture permeability for a long time. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing anti-fouling, oil-repellent and moisture-permeable cotton fiber and a fabric using the same.

[0006] A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) placing the cotton fiber bundle in an enzyme treatment solution containing lipase and treating it with ultrasonic oscillation; B) After washing, the cotton fibers are placed in a weak acid bath and then dehydrated to a moisture content of ≤60%; C) placing the dehydrated cotton fibers in a sealed container and steam treating the fibers with perfluorosilane vapor composed of a mixture of perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane; D) heat-curing the treated cotton fibers; E) After heat curing is completed, the cotton fiber bundle is taken out and allowed to recover naturally.

[0007] The present invention achieves functionalization of the cotton fiber surface by performing an enzymatic dewaxing treatment under weakly alkaline conditions, followed by a weak acid bath neutralization, moisture control, low-pressure perfluorosilane vapor deposition, and a two-stage thermal curing process, combined with a moisture resorption and humidity control step. This functionalization imparts significant oil and water repellency to the cotton fiber bundles while maximally preserving the fibers' original breathable channels, thereby improving protective performance while maintaining good water vapor permeability and wearing comfort.

[0008] During the first stage of enzymatic dewaxing, lipase efficiently degrades wax and attached impurities on the cotton fiber surface, providing ample reaction sites for subsequent surface modification. This dewaxing process not only removes excess oily components but also enhances the fiber's affinity and reactivity for subsequent treatment solutions. Furthermore, ultrasonic oscillation treatment technology accelerates mass transfer between the enzyme molecules and the fiber interface through microjets and cavitation. Under ultrasonic oscillation, the instantaneous bursting of tiny bubbles generates high-pressure microjets, which impact the fiber surface and promote contact and reaction between the enzyme molecules and the wax layer, significantly enhancing the dewaxing effect. Through the synergistic effect of ultrasound, the cotton fiber surface becomes rougher during the treatment process, providing more active sites for subsequent silane bonding, strengthening the binding force between the silane and the fiber surface, and ensuring the stability and effectiveness of the subsequent silanization treatment.

[0009] The subsequent weak acid bath neutralizes the residual alkaline components and moderately adjusts the pH of the fiber surface, providing a more controlled chemical environment for silane deposition. The fiber surface becomes more hydrophilic, laying a good foundation for the next step of vapor deposition.

[0010] During the low-pressure vapor deposition process, silane vapor is evenly distributed and reacts with the aforementioned surface active sites, forming a stable bond to a certain extent, significantly reducing the surface free energy of the fiber, thereby giving the cotton fiber bundles excellent oil and water repellent properties.

[0011] Ultimately, moderate thermal curing can quickly promote further cross-linking and densification, reduce residual hydroxyl groups and unreacted groups, thereby improving the coating's resistance to washing, friction and dry cleaning, and avoiding the adverse effects of excessively high temperatures on the strength and color of cotton fibers.

[0012] The final moisture regain and humidity adjustment step is carried out at room temperature for 24 to 32 hours to restore the moisture content of the cotton fiber bundle to a balanced state, further improve the soft feel and stabilize its protective properties.

[0013] Preferably, the frequency of the ultrasonic wave is 20 to 40 kHz.

[0014] Preferably, the enzyme treatment solution comprises lipase, glycine, a nonionic surfactant and urea, wherein the concentration of lipase is 1.2-1.8 g / L, the concentration of glycine is 0.3-0.6 g / L, the concentration of nonionic surfactant is 0.2-0.5 g / L and the concentration of urea is 0.5-1.0 g / L.

[0015] In step A, the formulation of the lipase treatment solution ensures efficient removal of wax from the cotton fiber surface while maintaining the physical properties of the cotton fiber to the greatest extent possible. Specifically, the lipase concentration is set at 1.2 to 1.8 g / L. Within this range, the lipase can significantly reduce the adhesion of wax under relatively mild conditions, causing it to fall off the fiber surface, thereby exposing more active sites and providing a good foundation for subsequent processing steps. Therefore, by controlling the lipase concentration, the cleavage effect can be ensured while avoiding fiber damage caused by excessive concentration, thereby effectively maintaining the mechanical strength of the cotton fiber.

[0016] Glycine, present in the treatment solution at a concentration of 0.3 to 0.6 g / L, acts as a buffer, stabilizing the pH of the reaction solution in a near-neutral to slightly alkaline environment. Glycine not only plays a crucial role in pH regulation but also forms reversible hydrogen bonds with hydroxyl groups on the fiber surface, further enhancing the fiber's surface hydrophilicity and promoting the binding of molecules like silane to the fiber during subsequent treatment.

[0017] Nonionic surfactants significantly reduce the surface tension of the treatment solution, promoting better penetration of lipase molecules onto the fiber surface. The addition of urea further loosens the microcrystalline regions on the fiber surface through a weak denaturing effect, enhancing the fiber's hydrophilicity and improving its structure, making its surface more accessible to the enzyme molecules in the treatment solution. Urea also reduces the tight structure within the fiber through denaturation, thereby increasing the enzyme's accessibility to the wax layer.

[0018] Preferably, the enzyme treatment solution further comprises acid cutase, and the mass ratio of lipase to acid cutase is 1:0.5-2.

[0019] In step A, acid cutase can effectively cut the ester bonds and long-chain fatty acids in cotton wax, promoting the degradation of the wax layer, thereby improving the depth and thoroughness of the dewaxing process. Lipase and acid cutase, through a dual attack on the wax on the surface of cotton fibers, not only make the wax layer more thoroughly peeled, but also improve the accessibility and reaction efficiency of the enzyme to the wax layer. The unique ester bond hydrolysis function of acid cutase and the fatty acid cleavage effect of lipase cooperate with each other to form a complementary effect, ensuring that there is basically no residual wax component on the surface of the cotton fiber, facilitating the smooth progress of subsequent treatment.

[0020] Preferably, the pH of the weak acid bath in step B is 4.5-5.5, the concentration of the citric acid is 2-5 g / L, the acid bath temperature is 50-60° C., the treatment time is 3-5 minutes, and after treatment, the product is dried by hot air to a moisture content of ≤10%.

[0021] In step B, the concentration of citric acid in the weak acid bath is controlled at 2-5 g / L, which can effectively and selectively complex the metal ions that may remain on the fiber surface and reduce the interference of metal ions. Secondly, the introduction of citric acid can effectively adjust the pH value of the fiber surface, providing an ideal environment for the silane hydrolysis-condensation reaction, ensuring that the chemical reaction between silane and the fiber surface is controllable and efficient. After citric acid treatment, Step B further controls the fiber's moisture content to ≤10%. This treatment not only effectively removes excess moisture from the fiber but also prevents the pre-agglomeration of silane molecules during vapor deposition, which can occur due to excess moisture. Excessive moisture can cause silane molecules to aggregate before effectively bonding to the fiber surface, thus impairing the bond between the silane and the fiber.

[0022] Preferably, 0.5-1.5 g / L of silane coupling agent KH-550 is also added to the weak acid bath in step B.

[0023] In step B, adding 0.5-1.5 g / L of the silane coupling agent KH-550 (γ-aminopropyltriethoxysilane) to the weak acid bath significantly improves the efficiency and stability of the subsequent silanization process. This is because the amino groups in the KH-550 molecule can undergo an in-situ condensation reaction with the hydroxyl groups on the fiber surface, potentially forming an aminopropyl-fiber intermediate layer. This intermediate layer not only enhances the fiber's surface affinity but also provides an effective reaction site for the subsequent deposition of perfluorosilane. The amino groups and the deposited perfluorosilane can form a silicon-oxygen network co-condensation or hydrogen bonding, significantly improving the adhesion and peel resistance of the low-surface-energy layer. KH-550 also mitigates the negative impact of the subsequent perfluorosilane chain rigidity on fiber flexibility.

[0024] Secondly, the fibers treated with glycine form reversible hydrogen bonds on the surface, which can enhance the binding force between KH-550 molecules and fibers. Through this chemical interaction, the bond between KH-550 and fibers becomes stronger, and the subsequent distribution uniformity of perfluorosilane molecules on the fiber surface and the interfacial adhesion strength are improved, thereby significantly improving the antifouling and oil repellency while maintaining good moisture permeability and durability. Preferably, in the perfluorosilane vapor of step C, perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane are mixed in a mass ratio of 1:1 to 1:3, the vapor concentration is controlled to be 4 to 5 wt%, and the vapor flow rate is controlled to be 0.6 to 0.8 mL·min -1.

[0025] Combine perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane in a mass ratio of 1:1 to 1:3, and control the vapor concentration to 4 to 5 wt% and the flow rate to 0.6 to 0.8 mL min -1 , which can collaboratively construct a long-chain-short-chain perfluoroalkyl mixed hydrophobic orientation structure on the fiber surface: the long chain segments reduce the surface energy, the short chain segments fill the interchain gaps and inhibit the brittle cracking caused by excessive crystallinity, thereby improving oil resistance and flexibility.

[0026] Preferably, step C is carried out in a sealed container at an absolute pressure of 0.08 to 0.10 MPa, and 0.5 to 1.5 vol% water vapor is carried.

[0027] In step C, the deposition environment is strictly controlled at an absolute pressure of 0.08 to 0.10 MPa, and 0.5–1.5 vol% water vapor is simultaneously introduced. This promotes rapid and complete vaporization of the perfluorosilane at a relatively low boiling point. Furthermore, the presence of trace amounts of water vapor can better trigger the controlled hydrolysis-condensation reaction of the silane molecules, allowing Si–O–Si bonds to grow uniformly and layer by layer on the fiber surface with a high probability, ultimately forming a continuous and dense silicon-oxygen network. This network can enhance the durability of the antifouling and oil-repellent properties.

[0028] Secondly, the low-pressure environment, on the one hand, increases the mean free path of silane vapor and significantly enhances its diffusion and penetration depth into the cotton fiber bundle; on the other hand, it inhibits the spontaneous aggregation caused by excessive local silane concentration, thereby effectively avoiding surface defects.

[0029] Preferably, step D uses two-stage thermal curing: pre-curing at 100-110° C. for 2-3 minutes and then final curing at 130-140° C. for 1-2 minutes.

[0030] In step D, a two-stage heat treatment, combining a pre-cure at 100-110°C for 2-3 minutes and a final cure at 130-140°C for 1-2 minutes, achieves an optimal balance between thermodynamics and fiber tolerance. The first pre-cure stage involves a gentle temperature increase, allowing for the full initial condensation reaction between silane and fiber, and between silane and silane. This also facilitates the smooth escape of low-molecular-weight byproducts such as ethanol and trace amounts of water from the internal pores of the cotton fiber bundle, thereby preventing microcracks or bubbles from evaporation during the subsequent high-temperature stage. The subsequent final cure at 130–140°C achieves a high degree of cross-linking and densification of the silicone network through a short temperature increase, significantly reducing the content of residual hydroxyl groups and unreacted ethoxy groups, and comprehensively improving the durability and comfortable feel of the cotton fiber bundle.

[0031] The invention discloses an antifouling, oil-repellent and moisture-permeable cotton fiber prepared by the method for preparing the antifouling, oil-repellent and moisture-permeable cotton fabric. The water vapor permeability index of the fabric made of the antifouling, oil-repellent and moisture-permeable cotton fiber is 95-98% of that of the fabric made of untreated cotton fiber bundles, the water repellency grade is ≥5, and the oil repellency grade is ≥4.

[0032] The water vapor permeability index of the final fabric remains at 95-98% of that of the fabric made from untreated cotton fiber bundles, indicating that the ultra-thin and ordered fluorine-containing layer does not block the intrinsic micropores; at the same time, the water repellency level is ≥5 and the oil repellency level is ≥4, indicating that the multi-scale rough / low-energy interface formed can effectively repel non-polar and weakly polar pollutants.

[0033] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in the following aspects: The present invention achieves precise low-surface-energy modification of the cotton fiber surface through processes such as weak alkaline enzyme dewaxing, weak acid bath neutralization, low-pressure perfluorosilane vapor deposition, two-stage thermal curing, and moisture regain and humidity control. While significantly improving the water and oil repellency, it also improves the anti-fouling and oil repellency and moisture permeability of the cotton fiber. Among them, citric acid and KH-550 pre-complexation / coupling effectively inhibit metal ion interference and provide a uniform and firm chemical anchor for the long-short chain mixed arrangement of perfluorodecyl-perfluorooctylsilane; the vapor deposition under specific water vapor conditions and the curing method of two-stage heat treatment densify the Si-O-Si network while avoiding the adverse effects of high temperature on the fiber color and mechanical properties. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the embodiments.

[0035] Material: Cotton fiber bundle (length 28 mm, linear density 1.4 dtex); Lipase (activity 10,000 U / g); Cutinase (standard Chinese name is cutin esterase, activity is 5000U / g); Glycine (analytical grade); Nonionic surfactant (nonylphenol polyoxyethylene ether); Urea (analytical grade); Citric acid (analytical grade); Silane coupling agent KH-550 (γ-aminopropyltriethoxysilane).

[0036] Example 1 A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) Place the cotton fiber bundle in a constant-temperature ultrasonic waterbath. Prepare a lipase treatment solution: 1.5 g / L lipase, 0.4 g / L glycine, 0.3 g / L nonionic surfactant, 0.8 g / L urea, and 1.125 g / L acid cutase. Adjust the pH to 8.0, the bath ratio to 1:20, and the temperature to 47 ± 2°C. Start the ultrasonic treatment system (20 kHz frequency, 200 W power) and conduct the ultrasonic treatment for 30 minutes at a constant temperature. After treatment, remove the cotton fiber bundle and rinse it with deionized water twice for 2 minutes each. The wax loss rate was controlled to 1.0 wt% (determined by Soxhlet extraction).

[0037] B) Prepare a weak acid bath: Mix 3g / L citric acid and 1g / L silane coupling agent KH-550 and adjust the bath pH to 5. Soak the washed cotton fiber bundle for 5 minutes at a bath ratio of 1:20 at 55°C. Dehydrate the cotton fiber bundle using a centrifuge (800 rpm, 1 minute) to a moisture content of ≤60%. Dry the cotton fiber bundle in a hot air oven at 90-100°C for 10 minutes to a moisture content of ≤10% (determined by the drying method).

[0038] C) The dried cotton fiber bundle was placed in a sealed container preheated at 100°C. Perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane were mixed in a 1:1 mass ratio to produce a 4 wt% vapor. The vapor flow rate was adjusted to 0.7 mL / min using an electronic flow control system. -1 At the same time, 1.0 vol% water vapor was introduced into the container. The absolute pressure was maintained at 0.09 MPa and the reaction was continued for 40 min.

[0039] D) The treated cotton fiber bundles were immediately placed in a hot air oven for two-stage thermal curing. The first stage was a pre-curing temperature of 105°C for 2.5 minutes, and the second stage was a final curing temperature of 135°C for 1.5 minutes.

[0040] E) After heat curing is completed, the cotton fiber bundle is taken out and allowed to recover naturally in a constant temperature and humidity room at a relative humidity of 65±5% and a temperature of 20±2℃ for 24 hours to ensure that the molecular chains of the finishing agent are fully arranged and fixed.

[0041] The cotton fibers prepared above were used for spinning, and a cotton yarn with a yarn count of 40 was produced by ring spinning. The cotton yarn was woven into a cotton grey fabric using a plain weave. The grey fabric had a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm. The fabric had a uniform surface and a stable structure, and was suitable for further dyeing and finishing.

[0042] Example 2 A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) Place cotton fibers in a constant-temperature ultrasonic waterbath. Prepare a lipase treatment solution: 1.8 g / L lipase, 0.6 g / L glycine, 0.5 g / L nonionic surfactant, 1.0 g / L urea, and 2.0 g / L acid cutase. Adjust the pH to 8.5, the bath ratio to 1:20, and the temperature to 47 ± 2°C. Start the ultrasonic treatment system (20 kHz frequency, 250 W power) and conduct the ultrasonic treatment for 35 minutes at a constant temperature. After treatment, remove the cotton fiber bundle and rinse it twice with deionized water for 2 minutes each. The wax loss was controlled to 1.2 wt% (determined by Soxhlet extraction).

[0043] B) Prepare a weak acid bath: Mix 5g / L citric acid and 1.5g / L silane coupling agent KH-550 and adjust the bath pH to 5. Soak the washed cotton fiber bundle for 5 minutes at a bath ratio of 1:20 at 60°C. Dehydrate the bundle using a centrifuge (1000 rpm for 2 minutes) to a moisture content of ≤60%. Dry the bundle in a hot air oven at 100°C for 12 minutes to a moisture content of ≤10% (determined by the drying method).

[0044] C) The dried cotton fiber bundle was placed in a sealed container preheated at 110°C. Perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane were mixed in a 1:2 mass ratio to produce a 5 wt% vapor. The vapor flow rate was adjusted to 0.8 mL / min using an electronic flow control system. -1 At the same time, 1.5 vol% water vapor was introduced into the container. The absolute pressure was maintained at 0.1 MPa and the reaction was continued for 45 min.

[0045] D) The treated cotton fiber bundles were immediately placed in a hot air oven for two-stage thermal curing. The first stage was a pre-curing temperature of 110°C for 3 minutes, and the second stage was a final curing temperature of 140°C for 2 minutes.

[0046] E) After heat curing is completed, the cotton fiber bundle is taken out and allowed to recover naturally in a constant temperature and humidity room at a relative humidity of 65±5% and a temperature of 20±2℃ for 30 hours to ensure that the molecular chains of the finishing agent are fully arranged and fixed.

[0047] The cotton fibers prepared above were used for spinning, and a cotton yarn with a yarn count of 40 was produced by ring spinning. The cotton yarn was woven into a cotton grey fabric using a plain weave. The grey fabric had a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm. The fabric had a uniform surface and a stable structure, and was suitable for further dyeing and finishing.

[0048] Example 3 A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) Place cotton fibers in a constant-temperature ultrasonic waterbath. Prepare a lipase treatment solution: 1.2 g / L lipase, 0.3 g / L glycine, 0.2 g / L nonionic surfactant, 0.5 g / L urea, and 1.0 g / L acid cutase. Adjust the pH to 7.5, the bath ratio to 1:20, and the temperature to 47 ± 2°C. Start the ultrasonic treatment system (20 kHz frequency, 150 W power) and conduct ultrasonic treatment at a constant temperature for 25 minutes. After treatment, remove the fibers and rinse them with deionized water twice for 2 minutes each. The wax loss was controlled to 0.8 wt% (determined by Soxhlet extraction).

[0049] B) Prepare a weak acid bath: Mix 2g / L citric acid and 0.5g / L silane coupling agent KH-550 and adjust the bath pH to 5. Soak the washed fibers for 5 minutes at a bath ratio of 1:20 at 50°C. Dehydrate using a centrifuge (600 rpm, 1 minute) to a moisture content of ≤60%. Dry the fibers in a hot air oven at 90°C for 8 minutes to a moisture content of ≤10% (determined by the drying method).

[0050] C) The dried fiber was placed in a sealed container preheated at 95°C. Perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane were mixed in a 1:1 mass ratio to produce a 3 wt% vapor. The vapor flow rate was adjusted to 0.6 mL / min using an electronic flow control system. -1 At the same time, 0.5 vol% water vapor was introduced into the container. The absolute pressure was maintained at 0.08 MPa and the reaction was continued for 35 min.

[0051] D) The treated fibers were immediately placed in a hot air oven for two-stage thermal curing. The first stage was a pre-curing temperature of 100°C for 2 minutes, and the second stage was a final curing temperature of 130°C for 1 minute.

[0052] E) After heat curing is completed, the fiber is taken out and allowed to recover naturally in a constant temperature and humidity room at a relative humidity of 65±5% and a temperature of 20±2℃ for 24 hours to ensure that the molecular chains of the finishing agent are fully arranged and fixed.

[0053] The cotton fibers prepared above were used for spinning, and a cotton yarn with a yarn count of 40 was produced by ring spinning. The cotton yarn was woven into a cotton grey fabric using a plain weave. The grey fabric had a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm. The fabric had a uniform surface and a stable structure, and was suitable for further dyeing and finishing.

[0054] Example 4 A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) Place cotton fibers in a constant-temperature ultrasonic waterbath. Prepare a lipase treatment solution: 1.5 g / L lipase, 0.4 g / L glycine, 0.3 g / L nonionic surfactant, 0.8 g / L urea, and 1.125 g / L acid cutase. Adjust the pH to 8.0, the bath ratio to 1:20, and the temperature to 47 ± 2°C. Start the ultrasonic treatment system (20 kHz frequency, 200 W power) and treat at a constant temperature for 30 minutes. After treatment, remove the fibers and rinse them with deionized water twice for 2 minutes each. Keep the wax loss to 1.0 wt% (determined by Soxhlet extraction).

[0055] B) Prepare a weak acid bath: Mix 3g / L of citric acid and adjust the bath pH to 5. Soak the washed fiber for 5 minutes at a bath ratio of 1:20 at 55°C. Dehydrate using a centrifuge (800 rpm, 1 minute) to a moisture content of ≤60%. Dry the fiber in a hot air oven at 90-100°C for 10 minutes to a moisture content of ≤10% (determined by the drying method).

[0056] C) The dried fiber was placed in a sealed container preheated at 100°C. Perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane were mixed in a 1:1 mass ratio to produce a 4 wt% vapor. The vapor flow rate was adjusted to 0.7 mL / min⁻¹ using an electronic flow control system. Simultaneously, 1.0 vol% water vapor was introduced into the container. The absolute pressure was maintained at 0.09 MPa and the reaction was continued for 40 minutes.

[0057] D) The treated fibers were immediately placed in a hot air oven for two-stage thermal curing. The first stage was a pre-curing temperature of 105°C for 2.5 minutes, and the second stage was a final curing temperature of 135°C for 1.5 minutes.

[0058] E) After heat curing is completed, the fiber is taken out and allowed to recover naturally in a constant temperature and humidity room at a relative humidity of 65±5% and a temperature of 20±2℃ for 24 hours to ensure that the molecular chains of the finishing agent are fully arranged and fixed.

[0059] The cotton fibers prepared above were used for spinning, and a cotton yarn with a yarn count of 40 was produced by ring spinning. The cotton yarn was woven into a cotton grey fabric using a plain weave. The grey fabric had a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm. The fabric had a uniform surface and a stable structure, and was suitable for further dyeing and finishing.

[0060] Example 5 A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) Place cotton fibers in a constant-temperature ultrasonic waterbath. Prepare a lipase treatment solution: 1.5 g / L lipase, 0.4 g / L glycine, 0.3 g / L nonionic surfactant, 0.8 g / L urea, and 1.125 g / L acid cutase. Adjust the pH to 8.0, the bath ratio to 1:20, and the temperature to 47 ± 2°C. Start the ultrasonic treatment system (20 kHz frequency, 200 W power) and treat at a constant temperature for 30 minutes. After treatment, remove the fibers and rinse them with deionized water twice for 2 minutes each. Keep the wax loss to 1.0 wt% (determined by Soxhlet extraction).

[0061] B) Prepare a weak acid bath: Mix 3g / L citric acid and 1g / L silane coupling agent KH-550 and adjust the bath pH to 5. Soak the washed fiber for 5 minutes at a bath ratio of 1:20 at 55°C. Dehydrate using a centrifuge (800 rpm, 1 minute) to a moisture content of ≤60%. Dry the fiber in a hot air oven at 90-100°C for 10 minutes to a moisture content of ≤10% (determined by the drying method).

[0062] C) The dried fiber was placed in a sealed container preheated at 100°C. Perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane were mixed in a 1:1 mass ratio to produce a 4 wt% vapor. The vapor flow rate was adjusted to 0.7 mL / min⁻¹ using an electronic flow control system. No water vapor was introduced into the container, and the reaction was carried out for 40 minutes at an absolute pressure of 0.09 MPa.

[0063] D) The treated fibers were immediately placed in a hot air oven for two-stage thermal curing. The first stage was a pre-curing temperature of 105°C for 2.5 minutes, and the second stage was a final curing temperature of 135°C for 1.5 minutes.

[0064] E) After heat curing is completed, the fiber is taken out and allowed to recover naturally in a constant temperature and humidity room at a relative humidity of 65±5% and a temperature of 20±2℃ for 24 hours to ensure that the molecular chains of the finishing agent are fully arranged and fixed.

[0065] The cotton fibers prepared above were used for spinning, and a cotton yarn with a yarn count of 40 was produced by ring spinning. The cotton yarn was woven into a cotton grey fabric using a plain weave. The grey fabric had a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm. The fabric had a uniform surface and a stable structure, and was suitable for further dyeing and finishing.

[0066] Comparative Example 1 A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber comprises the following steps: A) Place the cotton fiber bundle in a constant-temperature ultrasonic waterbath. Prepare a lipase treatment solution: 1.5 g / L lipase, 0.3 g / L nonionic surfactant, and 0.8 g / L urea. Adjust the pH to 8.0, the bath ratio to 1:20, and the temperature to 47 ± 2°C. Start the ultrasonic treatment system (20 kHz frequency, 200 W power) and conduct the ultrasonic treatment for 30 minutes at a constant temperature. After treatment, remove the cotton fiber bundle and rinse it twice with deionized water for 2 minutes each. The wax loss was controlled to 1.0 wt% (determined by Soxhlet extraction).

[0067] B) Prepare a weak acid bath: Mix 3g / L citric acid and 1g / L silane coupling agent KH-550 and adjust the bath pH to 5. Soak the washed cotton fiber bundle for 5 minutes at a bath ratio of 1:20 at 55°C. Dehydrate the cotton fiber bundle using a centrifuge (800 rpm, 1 minute) to a moisture content of ≤60%. Dry the cotton fiber bundle in a hot air oven at 90-100°C for 10 minutes to a moisture content of ≤10% (determined by the drying method).

[0068] C) The dried cotton fiber bundle was placed in a sealed container preheated at 100°C. Perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane were mixed in a 1:1 mass ratio to produce a 4 wt% vapor. The vapor flow rate was adjusted to 0.7 mL / min using an electronic flow control system. -1 At the same time, 1.0 vol% water vapor was introduced into the container. The absolute pressure was maintained at 0.09 MPa and the reaction was continued for 40 min.

[0069] D) The treated cotton fiber bundles were immediately placed in a hot air oven for two-stage thermal curing. The first stage was a pre-curing temperature of 105°C for 2.5 minutes, and the second stage was a final curing temperature of 135°C for 1.5 minutes.

[0070] E) After heat curing is completed, the cotton fiber bundle is taken out and allowed to recover naturally in a constant temperature and humidity room at a relative humidity of 65±5% and a temperature of 20±2℃ for 24 hours to ensure that the molecular chains of the finishing agent are fully arranged and fixed.

[0071] The cotton fibers prepared above were used for spinning, and a cotton yarn with a yarn count of 40 was produced by ring spinning. The cotton yarn was woven into a cotton grey fabric using a plain weave. The grey fabric had a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm. The fabric had a uniform surface and a stable structure, and was suitable for further dyeing and finishing.

[0072] The control group used untreated cotton fibers. Ring spinning was used to produce 40-count cotton yarn. The yarn was woven into a plain weave cotton fabric having a grammage of 150 g / m², a warp density of 120 strands / 10 cm, a weft density of 80 strands / 10 cm, and a width of 150 cm.

[0073] Performance testing 1. Wax removal rate test Method: Soxhlet extraction.

[0074] Procedure: Weigh 1 g of dry cotton fiber sample, add petroleum ether as solvent, extract in a Soxhlet extractor for 6 hours, dry, and weigh. Wax loss = (original mass - extracted mass) / original mass × 100%.

[0075] Standard: Refer to the extraction method in GB / T2910.1-2009.

[0076] 2. Water repellency test Method: spray method Procedure: Test fabrics by spraying distilled water at a standard angle and observing the wetting state of the fabric surface. The test is graded from 0 to 100 (in intervals of 10).

[0077] Requirements: The higher the water repellency level, the better the waterproof effect.

[0078] Standard: Refer to GB / T4745-2012.

[0079] 3. Oil repellency test Method: AATCC118-2013 (standard solution method) Procedure: Test the fabric by adding standard oil in order of grade (from No. 1 mineral oil to No. 8 liquid). If there is no penetration within 5 seconds, it is qualified. The grade range is 1 to 8.

[0080] Requirements: The higher the oil repellency rating, the more oleophobic the surface.

[0081] 4. Water vapor transmission index test Method: Refer to GB / T12704.2-2009 Procedure: Test fabrics, place the sample on a moisture permeable cup, and test the water vapor transmission rate under constant temperature and humidity conditions (unit: g·m -2 24h -1 ; Conversion to water vapor transmission index = treated sample moisture permeability / original untreated sample moisture permeability × 100%.

[0082] The test results of the above test are shown in Table 1 below.

[0083] Table 1

[0084] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing antifouling, oil-repellent and moisture-permeable cotton fiber, characterized in that: The following steps are involved: A) placing the cotton fiber bundle in an enzyme treatment solution containing lipase and treating it with ultrasonic oscillation; B) After washing, the cotton fibers are placed in a weak acid bath and then dehydrated to a moisture content of ≤60%; C) placing the dehydrated cotton fibers in a sealed container and steam treating the fibers with perfluorosilane vapor composed of a mixture of perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane; D) heat-curing the treated cotton fibers; E) After heat curing is completed, the cotton fiber bundle is taken out and allowed to recover naturally.

2. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 1, wherein: The pH of the enzyme treatment solution used in step A is 7.5 to 8.5, the temperature is 45 to 50° C., and the treatment time is 25 to 35 minutes.

3. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 2, wherein: The enzyme treatment solution comprises lipase, glycine, a nonionic surfactant and urea, wherein the concentration of lipase is 1.2-1.8 g / L, the concentration of glycine is 0.3-0.6 g / L, the concentration of nonionic surfactant is 0.2-0.5 g / L and the concentration of urea is 0.5-1.0 g / L.

4. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 3, wherein: The enzyme treatment solution also includes acid cutase, and the mass ratio of lipase to acid cutase is 1:0.5-2.

5. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 2, wherein: The pH of the weak acid bath in step B is 4.5-5.5, the concentration of the citric acid is 2-5 g / L, the acid bath temperature is 50-60° C., the treatment time is 3-5 minutes, and after treatment, the product is dried by hot air to a moisture content of ≤10%.

6. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 5, characterized in that: 0.5-1.5 g / L of silane coupling agent KH-550 is also added to the weak acid bath in step B.

7. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 1, wherein: In step C, perfluorodecyltriethoxysilane and perfluorooctyltrimethoxysilane are mixed in a mass ratio of 1:1 to 1:3, the concentration of the vapor is controlled to be 4 to 5 wt%, and the vapor flow rate is controlled to be 0.6 to 0.8 mL·min -1 .

8. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 1, wherein: In step C, the pressure in the sealed container is controlled to be 0.08-0.10 MPa, and 0.5-1.5 vol% water vapor is introduced into the sealed container.

9. The method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to claim 1, wherein: The thermal curing in step D includes two stages of thermal curing: pre-curing at 100-110° C. for 2-3 minutes and then final curing at 130-140° C. for 1-2 minutes.

10. An antifouling, oil-repellent and moisture-permeable cotton fiber obtained by the method for preparing the antifouling, oil-repellent and moisture-permeable cotton fiber according to any one of claims 1 to 9, characterized in that: The water vapor permeability index of the fabric made of the antifouling, oil-repellent and moisture-permeable cotton fiber is 95-98% of that of the fabric made of untreated cotton fiber bundles, the water repellency level is ≥5, and the oil repellency level is ≥4.

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