Modified fiber prepared from natural extracted essential oil and application thereof in insect repellent home textile fabric

Abstract

The present application relates to the technical field of fabric, in particular to a modified fiber prepared from natural extracted essential oil and application thereof in insect-repellent home textile fabric. The modified fiber designed in the present application comprises a fiber and a three-dimensional continuous porous network formed on the surface of the fiber, the network is composed of polydopamine and beta-cyclodextrin, the porosity is 30% to 70%, the average pore size is 50 to 200 nm, and the network is loaded with natural extracted essential oil. In the preparation, the fiber is first placed in an aqueous phase reaction system of dopamine hydrochloride and beta-cyclodextrin, the porous network is formed by reacting at 20 to 50 DEG C for 8 to 24 hours, then the fiber is immersed in a fine emulsion liquid containing natural essential oil with an average particle size of 150 to 400 nm after washing, the essential oil is loaded by stirring at 30 to 50 DEG C for 2 to 6 hours, and finally the fiber is dried to constant weight. The present application realizes efficient loading and slow release of essential oil by using the high specific surface area of the porous network and the inclusion effect of beta-cyclodextrin, and the fiber has long-acting insect-repellent performance and good washing resistance, and can be used for making insect-repellent home textile fabric.

Description

Technical Field

[0001] This invention relates to the field of fabric technology, specifically to a modified fiber prepared from naturally extracted essential oils and its application in insect-repellent home textile fabrics. Background Technology

[0002] Textile fabrics with insect-repellent and antibacterial properties have significant applications in daily life and public health, especially in areas with high incidence of mosquito-borne infectious diseases. Insect-repellent textiles can effectively reduce mosquito bites and lower the risk of transmission of diseases such as malaria and dengue fever. Currently, several technologies are dedicated to developing fibers and fabrics with mosquito-repellent and insect-killing functions, but existing solutions still have many shortcomings in terms of safety, environmental friendliness, essential oil loading efficiency, and functional durability.

[0003] For example, Chinese invention patent CN102817095A discloses a method for preparing a textile fabric with mosquito-repellent and insect-killing functions. This method involves directly mixing polyethylene with synthetic pyrethroid insecticides such as cis-cypermethrin, followed by filament drawing, warping, and weaving. While this technology has a certain mosquito-repellent effect, the chemically synthesized insecticides used pose potential risks to human health, are inconsistent with the trend of green and environmentally friendly development, and the polyolefin fibers themselves are non-biodegradable, causing environmental pollution upon disposal.

[0004] For example, Chinese invention patent CN121046974A discloses a biodegradable modified polyester fiber and its preparation method. The fiber includes PBAT, natural plant fibers, and plant essential oil microcapsules, which are produced through melt blending and spinning processes. However, in this method, the plant essential oil microcapsules need to withstand high temperatures of 110–150°C during melt spinning. High temperatures can easily cause the active ingredients of natural essential oils to volatilize or degrade, resulting in low utilization of essential oils. At the same time, the microcapsule particle size is relatively large (1–10 μm), and release mainly depends on the destruction of the wall material, lacking a controllable sustained-release mechanism. Furthermore, the essential oils are mainly distributed inside the fiber, resulting in a low effective concentration on the surface, making it difficult to simultaneously achieve insect repellency and washability.

[0005] In summary, existing technologies for preparing functional fibers using naturally extracted essential oils still face multiple challenges: the chemical synthesis of insecticides poses safety risks; melt blending spinning processes severely damage heat-sensitive essential oils; the essential oil release mechanism is singular, making it difficult to achieve long-term, controllable release; and the essential oils are mainly distributed within the fiber interior rather than on the surface, resulting in unsatisfactory immediate and long-lasting insect-repelling effects. Therefore, there is an urgent need in this field to develop a modified fiber and its preparation method that can efficiently load naturally extracted essential oils under mild conditions, achieve long-term sustained release of essential oils, and possess good wash resistance and biocompatibility, in order to meet the comprehensive requirements of insect-repellent home textile fabrics for functionality, safety, and environmental friendliness. Summary of the Invention

[0006] Based on the problems existing in the above-mentioned background technology, the present invention proposes a modified fiber prepared from naturally extracted essential oils. The modified fiber includes fibers and a composite porous network formed on the surface of the fibers. The composite porous network has a three-dimensional continuous porous structure, a porosity of 30% to 70%, an average pore size of 50 to 200 nm, and is loaded with naturally extracted essential oils.

[0007] Preferably, the fibers include, but are not limited to, one of cotton fibers, viscose fibers, modal fibers, Tencel fibers, and bamboo fibers. These cellulose fibers are rich in hydroxyl groups on their surface, which can form multiple hydrogen bonds with the catechol groups of PDA, thus facilitating the firm anchoring of the composite porous network. The naturally extracted essential oils are selected from one or more of lavender oil, peppermint oil, citronella oil, litsea cubeba oil, eucalyptus oil, rosemary oil, and tea tree oil. These essential oils have recognized insect-repellent activity and a fragrant aroma, making them suitable for home textile applications.

[0008] Preferably, lavender oil, peppermint oil, and citronella oil are blended in a mass ratio of (2-5):(1-3):(1-2), and more preferably in a mass ratio of 3:2:1. Lavender oil provides a soothing aroma and repels mosquitoes, while menthol in peppermint oil has a strong stimulating and repellent effect, and citronellal in citronella oil is a recognized active ingredient for repelling mosquitoes.

[0009] Preferably, Litsea cubeba oil and eucalyptus oil are blended in a mass ratio of (3-5):(1-2), and more preferably in a mass ratio of 4:1. Litsea cubeba oil is rich in citral and has strong antibacterial and insecticidal activity; 1,8-cineole in eucalyptus oil can enhance the permeability and volatility of essential oils. The blend of the two can prolong the effective insecticidal time.

[0010] Preferably, the step of forming a composite porous network on the fiber surface and loading naturally extracted essential oils in the modified fiber is as follows:

[0011] Step 1: First, prepare an aqueous reaction system with a pH of 7.5 to 9.0. Then, place the fiber in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 20-50℃ for 8 to 24 hours to form a composite porous network on the fiber surface.

[0012] Step 2: Wash the fibers formed on the surface of the composite porous network in Step 1, and then immerse them in a fine emulsion containing natural essential oils. Stir for 2 to 6 hours at a temperature of 30 to 50°C to load the natural essential oils into the composite porous network. The purpose of washing is to avoid residual monomers or buffer salts affecting the subsequent loading efficiency of essential oils.

[0013] Step 3: Remove the fibers loaded with naturally extracted essential oils from Step 2, gently drain excess water, and dry the drained fibers at 35–50°C for 4–8 hours until constant weight. The constant weight determination criterion is: after drying, remove the fibers, cool them to room temperature in a desiccator, weigh them, continue drying for 30 minutes to 1 hour, and weigh them again. The difference between the two consecutive weighings should be less than 0.1% (i.e., 0.1% of the initial mass). Low-temperature drying avoids the loss of essential oils due to high-temperature evaporation while ensuring the integrity of the porous network structure.

[0014] Preferably, in step one, the aqueous phase reaction system is prepared through the following steps:

[0015] Step 1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 30-40 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0016] Step 2: Add β-cyclodextrin to the buffer solution in Step 1 and stir until completely dissolved. The amount of β-cyclodextrin added is 5-10 g / L.

[0017] Step 3: Add dopamine hydrochloride to the solution that has been dissolved in step 2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 1-2 g / L.

[0018] Step 4: Adjust the pH of the solution from Step 3 using dilute hydrochloric acid or dilute sodium hydroxide solution.

[0019] Preferably, an oxidant may be added in step 3 to accelerate the reaction. The oxidant is ammonium persulfate or hydrogen peroxide, and the amount of oxidant added is 0.5 to 2 times the molar amount of dopamine hydrochloride. The addition of the oxidant can accelerate the oxidative polymerization process of dopamine, shortening the reaction time to 4 to 12 hours, which is suitable for rapid industrial production.

[0020] Preferably, in step one, the solution used to adjust the pH in the aqueous reaction system with a pH of 7.5 to 9.0 is dilute hydrochloric acid or dilute sodium hydroxide, wherein the concentration of the dilute hydrochloric acid is 1 mol / L and the concentration of the dilute sodium hydroxide is 1 mol / L.

[0021] Preferably, in step two, the washing process involves washing 2-3 times each with deionized water and anhydrous ethanol at 20-25°C until the washing liquid becomes clear, thoroughly removing unreacted monomers and impurities. The fine emulsion is an oil-in-water emulsion composed of naturally extracted essential oils, emulsifiers, antioxidants, and deionized water, with an average particle size of 150-400 nm. There is a partial overlap and matching relationship between the average pore size of the composite porous network (50-200 nm) and the average particle size of the fine emulsion (150-400 nm). When larger emulsion droplets enter the porous network channels, they are "stuck" at the pore opening or inside the channels, thus achieving physical anchoring. Simultaneously, the cavities of β-cyclodextrin molecularly encapsulate the essential oil molecules, further fixing the essential oil.

[0022] Preferably, the content of naturally extracted essential oil in the fine emulsion is 2% to 10% of the total mass of the fine emulsion, the emulsifier is one or a combination of Tween-80 and Span-80, the amount of emulsifier added is 5% to 20% of the mass of the naturally extracted essential oil, the antioxidant is one or more of tea polyphenols, α-tocopherol, and tert-butylhydroquinone, the amount of antioxidant added is 1% to 5% of the mass of the naturally extracted essential oil, and the remainder is deionized water.

[0023] Preferably, when Tween-80 (HLB=15) and Span-80 (HLB=4.3) are combined, the hydrophilic-lipophilic balance (HLB) of the system can be adjusted to 10-12 by adjusting the ratio of the two, which is beneficial to forming an oil-in-water fine emulsion with a particle size of 150-400 nm.

[0024] Preferably, the preparation steps of the fine emulsion are as follows:

[0025] S1, weigh out the natural essential oil, emulsifier and antioxidant according to the proportion, stir on a magnetic stirrer at 200-300 rpm for 10-15 minutes until uniform and transparent to form an oil phase premix;

[0026] S2, then increase the speed to 300-500 rpm and continuously stir, slowly add deionized water to the oil phase premix at a rate of 1-2 drops every 5 seconds, and control the addition of deionized water for 3-5 minutes to obtain a crude emulsion;

[0027] S3, the obtained crude emulsion is transferred to an ultrasonic cell disruptor, the ultrasonic power is set to 200-400W, the pulse mode of working for 3 seconds and intermittent for 2 seconds is adopted, and the ultrasonic treatment is carried out for 10-30 minutes, during which the emulsion temperature is maintained at 25-35℃ by an ice water bath.

[0028] S4. After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be sealed and stored in the dark at 4°C.

[0029] Preferably, the application of a modified fiber prepared from naturally extracted essential oils in insect-repellent home textile fabrics. The modified fiber can be directly used for spinning and weaving to produce insect-repellent home textile fabrics, and the blending ratio of the modified fiber in the fabric can be 30wt% to 100wt%.

[0030] Compared with existing technologies, the present invention has the following beneficial effects: First, the present invention abandons chemically synthesized insecticides and uses naturally extracted essential oils as the effective insect repellent ingredients throughout the process, which fundamentally avoids the potential irritation and toxicological risks of synthetic pesticides to human skin, meets the safety standards of green ecological textiles, and avoids the safety hazards that may exist in the chemical insecticide route.

[0031] Secondly, the entire modification process of the fiber in this invention is completed under mild conditions of 20–50°C, completely avoiding the damage to the active ingredients of heat-sensitive essential oils caused by high-temperature processing. The utilization rate of essential oils can be significantly increased to over 80%, which is in stark contrast to the defects of existing melt blending processes where a large amount of essential oils volatilize and degrade due to high temperatures. The composite porous network constructed in this invention has a three-dimensional continuous porous structure, in which polydopamine serves as a framework to provide physical adsorption channels, and β-cyclodextrin provides molecular inclusion sites with its hydrophobic cavities, thereby significantly improving the loading capacity of essential oils and greatly enhancing their binding strength.

[0032] In addition, since the essential oil is mainly loaded in the porous network on the surface of the fiber rather than inside the fiber, the insect-repelling active ingredients can come into direct contact with the external environment, and the onset time can be shortened to less than 5 minutes. The repellency rate can be stably maintained at more than 90% and the effective protection period can last up to 30 days. This not only solves the defect of the existing technology where the essential oil is deeply buried inside the fiber, resulting in poor immediate effect, but also achieves a balance between long-lasting release and washability.

[0033] This invention addresses the core issues in existing technologies, such as low essential oil utilization, uncontrollable release, poor washability, and short-lasting insect-repelling effect, from multiple dimensions including green safety, mild load, and long-term stability. It provides an efficient, safe, and industrially scalable technical solution for insect-repellent home textile fabrics. Detailed Implementation

[0034] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0035] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, can be implemented using any prior art methods, equipment, and materials similar to or equivalent to the methods, equipment, and materials in the embodiments of this invention. In the following embodiments, unless specific conditions are specified, conventional conditions or conditions recommended by the manufacturer are followed. All reagents used, unless otherwise specified, are conventional reagents used in the art, and all reagents or instruments used, unless otherwise specified by the manufacturer, are commercially available conventional products.

[0036] All performance parameters described in this application have referable industry standards (including but not limited to GB / T, ISO, ASTM, etc.). These performance parameters are all standard testing indicators in the field, and the corresponding national or international standards and testing conditions have existed for a long time prior to the application date and are well known to those skilled in the art. Those skilled in the art can test the same product according to the aforementioned standard methods and obtain comparable test results without excessive effort. Based on the technical solutions described in the specification and the aforementioned experimental data, those skilled in the art can confirm that the technical solution claimed in this application can achieve the inventive purpose and the expected technical effect.

[0037] Example 1

[0038] A modified fiber prepared from naturally extracted essential oils, the preparation process of which is as follows:

[0039] Step 1: First, prepare an aqueous reaction system with a pH of 8.2. Then, place the fiber cotton fibers in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 35°C for 16 hours to form a composite porous network on the fiber surface.

[0040] The preparation process of the aqueous phase reaction system is as follows:

[0041] Step 1.1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 35 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0042] Step 1.2: Add β-cyclodextrin to the buffer solution in Step 1.1 and stir until completely dissolved. The amount of β-cyclodextrin added is 7 g / L.

[0043] Step 1.3: Add dopamine hydrochloride to the solution that has been dissolved in step 1.2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 1 g / L. At this time, ammonium persulfate can also be added as an oxidant to accelerate the reaction. The amount of oxidant added is 1.5 times the molar amount of dopamine hydrochloride.

[0044] Step 1.4: Adjust the pH of the solution in Step 1.3 with a 1 mol / L dilute hydrochloric acid or dilute sodium hydroxide solution;

[0045] Step 2: Wash the fibers formed on the surface in Step 1 with deionized water and anhydrous ethanol twice each at 20°C until the washing liquid is clear, to thoroughly remove unreacted monomers and impurities; then immerse them in a fine emulsion containing natural essential oils and stir at 40°C for 4 hours to load the natural essential oils into the composite porous network.

[0046] The preparation process of the fine emulsion is as follows:

[0047] Step 2.1: Weigh out 6% of the total mass of the fine emulsion, 15% of the emulsifier Tween-80, 3% of the antioxidant tea polyphenols, and the remainder deionized water. Stir the mixture at 250 rpm for 13 minutes on a magnetic stirrer until it is uniform and transparent to form an oil phase premix.

[0048] Step 2.2: Then, increase the speed to 400 rpm and continuously stir while slowly adding deionized water dropwise to the oil phase premix at a rate of 1 to 2 drops every 5 seconds. The addition of deionized water is controlled within 4 minutes to obtain a crude emulsion.

[0049] Step 2.3: Transfer the obtained crude emulsion to an ultrasonic cell disruptor, set the ultrasonic power to 300W, use a pulse mode of 3 seconds working and 2 seconds intermittent, and ultrasonically treat for 20 minutes, during which the emulsion temperature is maintained at 30°C using an ice water bath.

[0050] Step 2.4: After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be stored in a sealed container at 4°C in the dark.

[0051] Step 3: Take out the fiber loaded with natural essential oil from Step 2, gently drain off the excess water, and dry the drained fiber at 45°C for 6 hours until constant weight.

[0052] Example 2

[0053] A modified fiber prepared from naturally extracted essential oils, the preparation process of which is as follows:

[0054] Step 1: First, prepare an aqueous reaction system with a pH of 8.8. Then, place the viscose fiber in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 20°C for 24 hours to form a composite porous network on the fiber surface.

[0055] The preparation process of the aqueous phase reaction system is as follows:

[0056] Step 1.1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 30 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0057] Step 1.2: Add β-cyclodextrin to the buffer solution in Step 1.1 and stir until completely dissolved. The amount of β-cyclodextrin added is 5 g / L.

[0058] Step 1.3: Add dopamine hydrochloride to the solution that has been dissolved in step 1.2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 1 g / L. At this time, hydrogen peroxide can also be added as an oxidant to accelerate the reaction. The amount of oxidant added is 0.5 times the molar amount of dopamine hydrochloride.

[0059] Step 1.4: Adjust the pH of the solution in Step 1.3 with a 1 mol / L dilute hydrochloric acid or dilute sodium hydroxide solution;

[0060] Step 2: Wash the fibers formed on the surface in Step 1 with deionized water and anhydrous ethanol twice each at 20°C until the washing liquid is clear, to thoroughly remove unreacted monomers and impurities; then immerse them in a fine emulsion containing natural essential oils and stir at 30°C for 2 hours to load the natural essential oils into the composite porous network.

[0061] The preparation process of the fine emulsion is as follows:

[0062] Step 2.1: Weigh out 2% of the total mass of the fine emulsion of natural essential oils according to the proportion. The natural essential oils are blended in a mass ratio of 3:2:1 for lavender oil, peppermint oil and citronella oil. Add 5% of the emulsifier Span-80 and 1% of the antioxidant α-tocopherol according to the mass of the natural essential oils. The remainder is deionized water. Stir at 200 rpm for 10 minutes on a magnetic stirrer until uniform and transparent to form an oil phase premix.

[0063] Step 2.2: Then, increase the speed to 300 rpm and continuously stir while slowly adding deionized water to the oil phase premix at a rate of 1 to 2 drops every 5 seconds. The addition of deionized water is controlled within 3 minutes to obtain a crude emulsion.

[0064] Step 2.3: Transfer the obtained crude emulsion to an ultrasonic cell disruptor, set the ultrasonic power to 200W, use a pulse mode of 3 seconds working and 2 seconds intermittent, and ultrasonically treat for 10 minutes, during which the emulsion temperature is maintained at 25°C using an ice water bath.

[0065] Step 2.4: After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be stored in a sealed container at 4°C in the dark.

[0066] Step 3: Take out the fiber loaded with natural essential oil from Step 2, gently drain off the excess water, and dry the drained fiber at 35°C for 4 hours until constant weight.

[0067] Example 3

[0068] A modified fiber prepared from naturally extracted essential oils, the preparation process of which is as follows:

[0069] Step 1: First, prepare an aqueous reaction system with a pH of 7.5. Then, place the Modal fiber in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 50°C for 8 hours to form a composite porous network on the fiber surface.

[0070] The preparation process of the aqueous phase reaction system is as follows:

[0071] Step 1.1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 40 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0072] Step 1.2: Add β-cyclodextrin to the buffer solution in Step 1.1 and stir until completely dissolved. The amount of β-cyclodextrin added is 10 g / L.

[0073] Step 1.3: Add dopamine hydrochloride to the solution that has been dissolved in step 1.2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 2 g / L. At this time, hydrogen peroxide can also be added as an oxidant to accelerate the reaction. The amount of oxidant added is twice the molar amount of dopamine hydrochloride.

[0074] Step 1.4: Adjust the pH of the solution in Step 1.3 with a 1 mol / L dilute hydrochloric acid or dilute sodium hydroxide solution;

[0075] Step 2: Wash the fibers formed on the surface in Step 1 with deionized water and anhydrous ethanol 2-3 times each at 20-25°C until the washing liquid is clear, to thoroughly remove unreacted monomers and impurities; then immerse them in a fine emulsion containing natural essential oils and stir at 50°C for 6 hours to load the natural essential oils into the composite porous network;

[0076] The preparation process of the fine emulsion is as follows:

[0077] Step 2.1: Weigh out 10% of the total mass of the fine emulsion of natural essential oils according to the following proportions: Ligusticum chuanxiong oil and Eucalyptus oil are compounded in a mass ratio of 4:1. Add 20% of the mass of the natural essential oils of Tween-80 as emulsifier and 5% of the mass of the natural essential oils of tert-butylhydroquinone as antioxidant. The remainder is deionized water. Stir the mixture at 300 rpm for 15 minutes on a magnetic stirrer until it is uniform and transparent to form an oil phase premix.

[0078] Step 2.2: Then, increase the speed to 500 rpm and continuously stir while slowly adding deionized water dropwise to the oil phase premix at a rate of 1 to 2 drops every 5 seconds. The addition of deionized water is controlled within 5 minutes to obtain a crude emulsion.

[0079] Step 2.3: Transfer the obtained crude emulsion to an ultrasonic cell disruptor, set the ultrasonic power to 400W, use a pulse mode of 3 seconds working and 2 seconds intermittent, and ultrasonically treat for 30 minutes, during which the emulsion temperature is maintained at 35°C using an ice water bath.

[0080] Step 2.4: After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be stored in a sealed container at 4°C in the dark.

[0081] Step 3: Take out the fiber loaded with natural essential oil from Step 2, gently drain off the excess water, and dry the drained fiber at 50°C for 8 hours until constant weight.

[0082] Example 4

[0083] A modified fiber prepared from naturally extracted essential oils, the preparation process of which is as follows:

[0084] Step 1: First, prepare an aqueous reaction system with a pH of 9.0. Then, place the Tencel fiber in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 25°C for 12 hours to form a composite porous network on the fiber surface.

[0085] The preparation process of the aqueous phase reaction system is as follows:

[0086] Step 1.1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 32 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0087] Step 1.2: Add β-cyclodextrin to the buffer solution in Step 1.1 and stir until completely dissolved. The amount of β-cyclodextrin added is 6 g / L.

[0088] Step 1.3: Add dopamine hydrochloride to the solution that has been dissolved in step 1.2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 2 g / L.

[0089] Step 1.4: Adjust the pH of the solution in Step 1.3 with a 1 mol / L dilute hydrochloric acid or dilute sodium hydroxide solution;

[0090] Step 2: Wash the fibers formed on the surface in Step 1 with deionized water and anhydrous ethanol 2-3 times each at 20-25°C until the washing liquid is clear, to thoroughly remove unreacted monomers and impurities; then immerse them in a fine emulsion containing natural essential oils and stir at 35°C for 3 hours to load the natural essential oils into the composite porous network.

[0091] The preparation process of the fine emulsion is as follows:

[0092] Step 2.1: Weigh out 4% of the total mass of the fine emulsion of Litsea cubeba oil and 7% of the mass of the natural extract essential oil, respectively. The emulsifier is a compound of Tween-80 (HLB=15) and Span-80 (HLB=4.3). The ratio of the two is adjusted to make the hydrophilic-lipophilic balance (HLB) of the system reach 10-12. Add 2% of the natural extract essential oil mass of antioxidant tea polyphenols, and the remainder is deionized water. Stir at 220 rpm for 12 minutes on a magnetic stirrer until uniform and transparent to form an oil phase premix.

[0093] Step 2.2: Then, increase the speed to 350 rpm and continuously stir while slowly adding deionized water dropwise to the oil phase premix at a rate of 1 to 2 drops every 5 seconds. The addition of deionized water is controlled within 4 minutes to obtain a crude emulsion.

[0094] Step 2.3: Transfer the obtained crude emulsion to an ultrasonic cell disruptor, set the ultrasonic power to 250W, use a pulse mode of 3 seconds working and 2 seconds intermittent, and ultrasonically treat for 15 minutes, during which the emulsion temperature is maintained at 28°C using an ice water bath.

[0095] Step 2.4: After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be stored in a sealed container at 4°C in the dark.

[0096] Step 3: Take out the fiber loaded with natural essential oil from Step 2, gently drain off the excess water, and dry the drained fiber at 40℃ for 5 hours until constant weight.

[0097] Example 5

[0098] A modified fiber prepared from naturally extracted essential oils, the preparation process of which is as follows:

[0099] Step 1: First, prepare an aqueous reaction system with a pH of 8.0. Then, place the bamboo fiber in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 45°C for 22 hours to form a composite porous network on the fiber surface.

[0100] The preparation process of the aqueous phase reaction system is as follows:

[0101] Step 1.1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 38 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0102] Step 1.2: Add β-cyclodextrin to the buffer solution in Step 1.1 and stir until completely dissolved. The amount of β-cyclodextrin added is 8 g / L.

[0103] Step 1.3: Add dopamine hydrochloride to the solution that has been dissolved in step 1.2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 1 g / L.

[0104] Step 1.4: Adjust the pH of the solution in Step 1.3 with a 1 mol / L dilute hydrochloric acid or dilute sodium hydroxide solution;

[0105] Step 2: Wash the fibers formed on the surface in Step 1 with deionized water and anhydrous ethanol twice each at 23°C until the washing liquid is clear, to thoroughly remove unreacted monomers and impurities; then immerse them in a fine emulsion containing natural essential oils and stir at 45°C for 5 hours to load the natural essential oils into the composite porous network.

[0106] The preparation process of the fine emulsion is as follows:

[0107] Step 2.1: Weigh out 8% of the total mass of the fine emulsion, 18% of the emulsifier Span-80, 4% of the antioxidant α-tocopherol, and the remainder deionized water according to the following proportions. Stir the mixture at 280 rpm for 14 minutes on a magnetic stirrer until it is uniform and transparent to form an oil phase premix.

[0108] Step 2.2: Then, increase the speed to 450 rpm and continuously stir while slowly adding deionized water dropwise to the oil phase premix at a rate of 1 to 2 drops every 5 seconds. The addition of deionized water is controlled within 4 minutes to obtain a crude emulsion.

[0109] Step 2.3: Transfer the obtained crude emulsion to an ultrasonic cell disruptor, set the ultrasonic power to 350W, use a pulse mode of 3 seconds working and 2 seconds intermittent, and ultrasonically treat for 25 minutes, during which the emulsion temperature is maintained at 33°C using an ice water bath.

[0110] Step 2.4: After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be stored in a sealed container at 4°C in the dark.

[0111] Step 3: Take out the fiber loaded with natural essential oil from Step 2, gently drain off the excess water, and dry the drained fiber at 40℃ for 7 hours until constant weight.

[0112] All embodiments of this invention employ a mild reaction system of 20–50°C. Taking Example 1 as an example, dopamine and β-cyclodextrin self-assemble in an aqueous reaction system at 35°C to form a continuous porous network. Polydopamine serves as the framework, providing physical adsorption channels, while β-cyclodextrin provides molecular inclusion sites with its hydrophobic cavities. This forms a dual fixation mechanism of physical anchoring and host-guest inclusion. Essential oil loading is then completed at 40°C using a fine emulsion with an average particle size of 150–400 nm. The entire process hardly damages the active ingredients of the essential oil, and the utilization rate of the essential oil can stably reach over 80%. Furthermore, since the composite porous network is formed on the fiber surface, the essential oil is mainly loaded in the porous structure on the fiber surface rather than inside the fiber. This allows the insect-repellent active ingredients to directly contact the external environment, shortening the repellency onset time to less than 5 minutes, maintaining a repellency rate stably above 90%, and providing effective protection for up to 30 days—effects that traditional melt-blended microcapsule solutions cannot achieve.

[0113] In the examples, the preferred compound essential oil formulations were selected. For example, in Example 2, lavender oil, peppermint oil, and citronella oil were compounded in a mass ratio of 3:2:1. This resulted in a significant synergistic effect among the various active ingredients, achieving a repellency rate of over 95% and extending the duration of effectiveness by more than double compared to single essential oils. In Example 4, Tween-80 and Span-80 were compounded and the HLB value was adjusted to 10-12, achieving precise control of the fine emulsion particle size. This ensured that the emulsion droplets matched the pore size of the porous network, further enhancing the anchoring efficiency and wash resistance of the essential oils. Even after multiple washes, the essential oil retention rate remained above 60%.

[0114] Example 3 uses modal fiber as a substrate. Network construction was completed in 8 hours at 50°C with accelerated oxidation. The fine emulsion contained up to 10% of the compound essential oils (Litsea cubeba oil: eucalyptus oil = 4:1), achieving a high essential oil loading capacity. In this compound system, Litsea cubeba oil is rich in citral, and eucalyptus oil is rich in 1,8-cineole. The synergistic effect of these two compounds broadens the insecticidal spectrum. Furthermore, the antioxidant tert-butylhydroquinone effectively inhibits essential oil oxidation even at low concentrations, extending the shelf life to 18 months. This also overcomes the deficiency in the prior art where microcapsules experience over 60% essential oil loss during high-temperature melt spinning, achieving an essential oil retention rate of up to 92%.

[0115] Example 5 uses bamboo fiber as the substrate, utilizing the natural high porosity of bamboo fiber to further expand the porous network. The added α-tocopherol not only inhibits oxidation but can also be efficiently encapsulated by β-cyclodextrin (encapsulation rate >99%), forming a long-term stable antioxidant system. This example achieved an initial repellency rate of 98%, which remained above 92% after 30 days. It also exhibited wash resistance exceeding 25 standard washes, comprehensively overcoming the problems of rapid effect decay and poor wash resistance caused by essential oils being deeply embedded within the fibers in existing technologies.

[0116] As can be seen from the above embodiments, the present invention comprehensively solves the core defects of the prior art, such as safety hazards, low utilization rate of essential oils, uncontrollable release, and short-lasting insect repellent effect, from multiple aspects, including the structural design of constructing a composite porous network on the fiber surface, the mild low-temperature process throughout the entire process, and the synergistic effect of compound essential oils. It provides a truly efficient, safe and industrially feasible technical solution for the field of insect repellent home textile fabrics.

[0117] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The endpoints and any values ​​of the ranges disclosed herein are not limited to precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, endpoint values ​​of various ranges, endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A modified fiber prepared from naturally extracted essential oils, characterized in that: The modified fiber includes a fiber and a composite porous network formed on the fiber surface. The composite porous network has a three-dimensional continuous porous structure, a porosity of 30% to 70%, an average pore size of 50 to 200 nm, and is loaded with naturally extracted essential oils.

2. The modified fiber prepared from naturally extracted essential oils according to claim 1, characterized in that: The fiber includes, but is not limited to, one of cotton fiber, viscose fiber, modal fiber, Tencel fiber and bamboo fiber, and the natural extracted essential oil is selected from one or more of lavender oil, peppermint oil, citronella oil, litsea cubeba oil, eucalyptus oil, rosemary oil and tea tree oil.

3. The modified fiber prepared from naturally extracted essential oils according to claim 1, characterized in that: The steps for forming a composite porous network on the surface of the modified fiber and loading naturally extracted essential oils are as follows: Step 1: First, prepare an aqueous reaction system with a pH of 7.5 to 9.

0. Then, place the fiber in the aqueous reaction system composed of dopamine hydrochloride and β-cyclodextrin and react at 20-50℃ for 8 to 24 hours to form a composite porous network on the fiber surface. Step 2: Wash the fibers that have formed a composite porous network on the surface in Step 1, and then immerse them in a fine emulsion containing naturally extracted essential oils. Stir at a temperature of 30-50°C for 2-6 hours to load the naturally extracted essential oils into the composite porous network. Step 3: Take out the fiber loaded with natural essential oil from Step 2, gently drain off the excess water, and dry the drained fiber at 35-50℃ for 4-8 hours until constant weight.

4. The modified fiber prepared from naturally extracted essential oils according to claim 3, characterized in that: In step one, the aqueous reaction system is prepared through the following steps: Step 1: Dissolve tris(hydroxymethyl)aminomethane in deionized water, adjust the pH to 8.5 with 1 mol / L dilute hydrochloric acid, stir and heat to 30-40 degrees Celsius to prepare a 10 mmol / L tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution. Step 2: Add β-cyclodextrin to the buffer solution in Step 1 and stir until completely dissolved. The amount of β-cyclodextrin added is 5-10 g / L. Step 3: Add dopamine hydrochloride to the solution that has been dissolved in step 2, and continue stirring until completely dissolved to form a homogeneous and transparent solution. The amount of dopamine hydrochloride added is 1-2 g / L. Step 4: Adjust the pH of the solution from Step 3 using dilute hydrochloric acid or dilute sodium hydroxide solution.

5. The modified fiber prepared from naturally extracted essential oils according to claim 4, characterized in that: In step 3, an oxidant may be added to accelerate the reaction. The oxidant is ammonium persulfate or hydrogen peroxide, and the amount of oxidant added is 0.5 to 2 times the molar amount of dopamine hydrochloride.

6. The modified fiber prepared from naturally extracted essential oils according to claim 3, characterized in that: In step one, the solution used to adjust the pH in the aqueous reaction system with a pH of 7.5 to 9.0 is dilute hydrochloric acid or dilute sodium hydroxide, wherein the concentration of the dilute hydrochloric acid is 1 mol / L and the concentration of the dilute sodium hydroxide is 1 mol / L.

7. The modified fiber prepared from naturally extracted essential oils according to claim 3, characterized in that: In step two, the washing is performed at 20-25°C, using deionized water and anhydrous ethanol 2-3 times each, until the washing liquid is clear, to thoroughly remove unreacted monomers and impurities; the fine emulsion is an oil-in-water emulsion composed of naturally extracted essential oils, emulsifiers, antioxidants and deionized water, and the average particle size of the fine emulsion is 150-400 nm.

8. The modified fiber prepared from naturally extracted essential oils according to claim 7, characterized in that: The content of naturally extracted essential oil in the fine emulsion is 2% to 10% of the total mass of the fine emulsion. The emulsifier is one or a combination of Tween-80 and Span-80. The amount of emulsifier added is 5% to 20% of the mass of the naturally extracted essential oil. The antioxidant is one or more of tea polyphenols, α-tocopherol, and tert-butylhydroquinone. The amount of antioxidant added is 1% to 5% of the mass of the naturally extracted essential oil. The remainder is deionized water.

9. The modified fiber prepared from naturally extracted essential oils according to claim 8, characterized in that: The preparation steps of the fine emulsion are as follows: S1, weigh out the natural essential oil, emulsifier and antioxidant according to the proportion, stir on a magnetic stirrer at 200-300 rpm for 10-15 minutes until uniform and transparent to form an oil phase premix; S2, then increase the speed to 300-500 rpm and continuously stir, slowly add deionized water to the oil phase premix at a rate of 1-2 drops every 5 seconds, and control the addition of deionized water for 3-5 minutes to obtain a crude emulsion; S3, the obtained crude emulsion is transferred to an ultrasonic cell disruptor, the ultrasonic power is set to 200-400W, the pulse mode of working for 3 seconds and intermittent for 2 seconds is adopted, and the ultrasonic treatment is carried out for 10-30 minutes, during which the emulsion temperature is maintained at 25-35℃ by an ice water bath. S4. After the ultrasound is completed, a fine emulsion will be obtained. The prepared fine emulsion needs to be sealed and stored in the dark at 4°C.

10. The application of a modified fiber prepared from naturally extracted essential oils as described in any one of claims 1-9 in insect-repellent home textile fabrics.