A mosquito-repellent fiber and its preparation method

Abstract

This invention discloses a mosquito-repellent fiber and its preparation method. The mosquito-repellent fiber has a circular core-sheath structure, comprising a core layer and a sheath layer surrounding the core layer. The core layer is made of pure polypropylene resin, and the sheath layer is made of polyester resin containing mosquito-repellent essential oil microcapsule particles. The content ratio of the core layer to the sheath layer, by mass percentage, is 30%-80% for the core layer and 20%-70% for the sheath layer. This invention provides a mosquito-repellent fiber and its preparation method. During high-temperature preparation, the mosquito-repellent fiber exhibits good airtightness of the microcapsule shell, excellent heat insulation performance, minimal loss of mosquito-repellent essential oil, and excellent mosquito-repellent performance.

Description

Technical Field

[0001] This invention relates to the field of fiber preparation, specifically to a mosquito-repellent fiber and its preparation method. Background Technology

[0002] Early research on mosquito-repellent fibers primarily focused on surface finishing methods, such as padding and coating to create mosquito-repellent fabrics. Other inventions disclosed methods involving solution spinning of mosquito repellents with spinning solutions, electrospinning of mosquito repellents with polylactic acid spinning solutions, and melt spinning of mosquito repellents directly with polyester resins. However, these methods, involving the direct addition of mosquito repellents, suffer from significant volatilization at high temperatures, resulting in a substantial loss of repellent and reduced effectiveness. Current technologies employing core-sheath structures to prepare mosquito-repellent fibers address the issues of rapid repellent release, poor washability, and short-lasting effects. However, since the repellent is typically located in the fiber core, even with pore-forming techniques to address release, the complete encapsulation of the core layer by the sheath fiber restricts diffusion to the fiber surface, further reducing the actual mosquito-repellent effect. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned defects or problems in the background art and provide a mosquito-repellent fiber and its preparation method. The mosquito-repellent fiber has good airtightness of the microcapsule shell and excellent heat insulation performance during the high-temperature preparation process, with little loss of mosquito-repellent essential oil and excellent mosquito-repellent performance.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The first technical solution relates to a mosquito-repellent fiber, which has a circular core-sheath structure, comprising a core layer and a sheath layer covering the outer periphery of the core layer; the core layer is pure polypropylene resin, and the sheath layer is polyester resin containing mosquito-repellent essential oil microcapsule particles; the content ratio of the core layer to the sheath layer by mass percentage is: the content of the core layer is 30%-80%, and the content of the sheath layer is 20%-70%.

[0006] The second technical solution is based on the first technical solution, wherein the content of the microcapsule particles in the skin layer is 0.5%-10% of polyester resin, and the loading rate of the mosquito repellent essential oil in the microcapsule particles is 30%-60%.

[0007] The third technical solution is based on the second technical solution, wherein the skin layer is processed using low-melting-point polyester resin with a melting point of 150℃-230℃.

[0008] The fourth technical solution is based on the third technical solution, wherein the microcapsule particles are prepared using melamine resin as the wall material and the mosquito repellent essential oil as the core material.

[0009] The fifth technical solution is based on the fourth technical solution, wherein the microcapsule particles are uniformly distributed inside the skin layer.

[0010] The sixth technical solution is based on the fifth technical solution, wherein the microcapsule particles are spherical nanoparticles with a particle size of 580 nm.

[0011] The seventh technical solution is based on the sixth technical solution, wherein the microcapsules are prepared by in-situ polymerization.

[0012] The eighth technical solution is based on the second technical solution, wherein the mosquito repellent essential oil is an essential oil with added permethrin.

[0013] The ninth technical solution is a method for preparing mosquito-repellent fiber based on any one of the first to eighth technical solutions, comprising the following steps: Step 1, preparation of microcapsules: mosquito-repellent essential oil is dripped into a styrene-maleic anhydride aqueous solution and emulsified for 1 hour to obtain a mosquito-repellent essential oil emulsion; melamine and formaldehyde are mixed at a molar ratio of 1 / 4-1 / 2, the pH is adjusted to 8.0-9.5, the temperature is controlled at 50℃-70℃, and a transparent melamine-formaldehyde prepolymer solution is prepared by continuous stirring; then the melamine-formaldehyde prepolymer is added to the mosquito-repellent essential oil emulsion and reacted at 50℃-70℃ for 0.5-2 hours, followed by drying to obtain microcapsules containing mosquito-repellent essential oil, wherein the decomposition temperature of the microcapsules is above 240℃; Step 2, preparation of polyester resin chips for microcapsules: polyester resin chips are prepared by... The polyester resin powder is obtained by pulverizing. The microcapsule powder and polyester resin powder are mixed evenly in a certain proportion, with the microcapsule powder accounting for 0.5%-10% of the polyester resin powder by mass. After being melt-extruded by a twin-screw extruder, the mixture is granulated to obtain mosquito-repellent microcapsule polyester resin chips. Step 3, preparation of mosquito-repellent fibers: The microcapsule polyester resin chips obtained in step 2 and polypropylene resin are melted separately by a twin-screw extruder, and then stretched by a two-component composite spinning machine and a drawing machine to obtain mosquito-repellent fibers. The melting temperature of the polyester resin is 150℃-230℃, the spinneret temperature is 170℃-240℃, the melting temperature of the polypropylene resin is 160℃-250℃, the spinneret temperature is 170℃-270℃, the drawing temperature is 70℃-110℃, and the total draw ratio is 2-5 times.

[0014] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Mosquito-repellent fiber is prepared by blending polyester resin with mosquito-repellent microcapsules to obtain mosquito-repellent polyester resin chips, then using mosquito-repellent polyester resin as the sheath and polypropylene resin as the core layer through melt spinning. Because the mosquito-repellent essential oil is in the sheath layer, it is more conducive to the diffusion of the essential oil to the fiber surface. Simultaneously, the use of mosquito-repellent microcapsule particles ensures that the mosquito-repellent essential oil is not destroyed during high-temperature melting. Tests show that the mosquito-repellent effect can reach grade B or higher. Due to the sheath-core structure, the fiber's draw ratio is increased, while the orientation of the molecular chains within the fiber is also increased. More intermolecular bonds are formed within the fiber, and the intermolecular distance is reduced, thus improving the fiber's mechanical strength. Tests show a breaking strength of 1.6–3.0 cN / dtex, indicating that this mosquito-repellent fiber has excellent mosquito-repellent effect and superior fiber strength.

[0016] 2. Microencapsulation technology is used to encapsulate mosquito repellent essential oil in sealed capsules within the skin layer, protecting the essential oil and controlling its release rate and duration.

[0017] 3. The melting point of conventional polyester resin is around 240 degrees Celsius. Therefore, during the spinning process, the processing temperature often needs to reach above 240 degrees Celsius. However, excessively high processing temperatures can cause ordinary mosquito-repellent microcapsules to rupture (due to their inability to withstand high temperatures), thus rendering them ineffective. Therefore, using low-melting-point polyester resin can relatively reduce the temperature of the material during spinning, improving the high-temperature rupture resistance of the microcapsules.

[0018] 4. The microcapsule particles are mosquito repellent essential oil particles coated with melamine resin. The mosquito repellent essential oil is coated with melamine resin with good sealing properties, which has a slow and long-lasting effect of releasing mosquito repellent essential oil.

[0019] 5. The microcapsule particles are evenly distributed inside the skin layer, and the mosquito-repellent essential oil is retained inside the microcapsules in the polyester resin. At room temperature, the mosquito-repellent essential oil diffuses out to achieve the mosquito-repellent effect. When extracted with methanol as a solvent, the initial release rate of the mosquito-repellent essential oil is 0.2-0.5 mmol / (L·d), indicating that while ensuring high temperature resistance and yarn strength, the microcapsules are not damaged and can release the mosquito-repellent essential oil normally. At the same time, the mosquito-repellent microcapsule particles are distributed inside the fiber, and the mosquito-repellent essential oil does not come into direct contact with the skin, making it safer and more reliable to use.

[0020] 6. The microcapsule particles are spherical nanoparticles. The smaller the particles, the better they are dispersed evenly in the fiber without affecting the physicochemical properties of the fiber itself. The particle size of the nanoparticles can be obtained by changing the emulsification rate according to the requirements. With an emulsification rate of 12,000 rpm, the particle size can reach 580 nm.

[0021] 7. The microcapsules are prepared by in-situ polymerization. This method utilizes the monomers to undergo a polycondensation reaction on the surface of the core material under the action of catalysts, initiators, emulsifiers and other auxiliaries. Through cross-linking and polymerization, a film-like substance is formed to coat the core material, thereby forming a phase change microcapsule material. This preparation method has mild reaction conditions and a simple process.

[0022] 8. Permethrin is extracted from chrysanthemum plants. It has a mosquito-repellent effect but is non-toxic and odorless to humans. It can be used for mosquito-repellent functions in textiles.

[0023] 9. Mosquito-repellent fiber is produced by blending polyester resin with mosquito-repellent microcapsules to obtain mosquito-repellent polyester resin chips. Microcapsule powder and polyester resin powder are mixed in a certain proportion, extruded and granulated, and then melt-spun with low-melting-point polyester resin as the outer layer and polypropylene as the core layer to obtain a mosquito-repellent composite fiber. The microcapsules have good high-temperature resistance, with a decomposition temperature above 240℃. When applied to polyester resin, the microcapsules will not rupture during the high-temperature melting process. During the high-temperature melting process, the mosquito-repellent essential oil in the microcapsules can only diffuse out through the pores of the melamine resin shell. The limited pores make the diffusion of the mosquito-repellent essential oil very slow at high temperatures, and a large amount of mosquito-repellent essential oil remains inside the microcapsules in the polyester resin. Through melt extrusion, the mosquito-repellent microcapsules are distributed in the fiber, and the mosquito-repellent essential oil diffuses out at room temperature to achieve the mosquito-repellent effect. This mosquito-repellent fiber has good airtightness of the microcapsule shell and excellent heat insulation performance during high-temperature preparation, with minimal loss of mosquito-repellent essential oil. It has advantages such as low cost, long mosquito-repellent cycle, good mosquito-repellent effect, and fast fiber spinning rate. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments are briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the mosquito-repellent fiber core structure in the embodiment;

[0026] Explanation of key figure labels:

[0027] Core layer 1; outer layer 2; microcapsule particles 3. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Unless otherwise expressly defined, the use of terms such as "first," "second," or "third" in the claims, description, and accompanying drawings of this invention is for distinguishing different objects and not for describing a specific order.

[0030] Unless otherwise expressly defined, in the claims, description, and accompanying drawings of this invention, the use of directional terms such as "center," "lateral," "longitudinal," "horizontal," "vertical," "top," "bottom," "inner," "outer," "upper," "lower," "front," "rear," "left," "right," "clockwise," and "counterclockwise" to indicate orientation or positional relationships is based on the orientation and positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the specific scope of protection of this invention.

[0031] Unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" used in the claims, description and drawings of this invention should be interpreted broadly to refer to any connection in which there is no displacement or relative rotation relationship between the two parties, including non-removable fixed connection, detachable fixed connection, integral connection and fixed connection by other means or components.

[0032] In the claims, description and accompanying drawings of this invention, the terms "comprising," "having," and variations thereof are used to mean "including but not limited to."

[0033] See Figure 1 , Figure 1 A schematic diagram of the mosquito-repellent fiber core-sheath structure in the embodiment is shown; a mosquito-repellent fiber has a circular core-sheath structure, which includes a core layer 1 and a sheath layer 2 covering the outer periphery of the core layer 1; the core layer 1 is pure polypropylene resin, and the sheath layer 2 is polyester resin containing mosquito-repellent essential oil microcapsule particles 3; the content ratio of the core layer 1 to the sheath layer 2 is by mass percentage: the content of the core layer 1 is 30%-80%, and the content of the sheath layer 2 is 20%-70%; in the core-sheath structure, the outer sheath layer 2 plays a role in covering and protecting the inner core layer 1, and the inner and outer layers are usually made of different materials, one material can meet the conventional physical and chemical properties of the yarn, and the other material can be used for functional composite; specifically, the circular core-sheath structure is a concentric circular core-sheath structure or an eccentric circular core-sheath structure.

[0034] The content of microcapsule particles 3 in the skin layer 2 is 0.5%-10% of polyester resin, and the loading rate of mosquito repellent essential oil in the microcapsule particles 3 is 30%-60%. The mosquito repellent essential oil is encapsulated in a closed capsule in the skin layer 2 using microcapsule technology, which protects the mosquito repellent essential oil from being damaged and controls the release rate and time of the mosquito repellent essential oil.

[0035] In this embodiment, the skin layer 2 is made of low-melting-point polyester resin with a melting point of 150℃-230℃. Conventional polyester resins have a melting point of around 240℃, so the processing temperature often needs to reach above 240℃ during spinning. Excessively high processing temperatures can cause ordinary mosquito-repellent microcapsules to rupture (due to their inability to withstand high temperatures), thus losing their function. Therefore, using low-melting-point polyester resin can relatively reduce the temperature during spinning, improving the microcapsules' resistance to high-temperature rupture.

[0036] In this embodiment, the microcapsule particles 3 are prepared by using melamine resin as the wall material and mosquito repellent essential oil as the core material. The microcapsule particles 3 are microcapsule particles 3 with melamine resin coated on the surface of mosquito repellent essential oil. The mosquito repellent essential oil is coated with melamine resin with good sealing properties as the wall material, which has the effect of slow and long-lasting release of mosquito repellent essential oil.

[0037] In this embodiment, the microcapsule particles 3 are uniformly distributed inside the skin layer 2, and the mosquito repellent essential oil is retained inside the microcapsules in the polyester resin. At room temperature, the mosquito repellent essential oil diffuses out to achieve the mosquito repellent effect. When extracted with methanol as a solvent, the initial release rate of the mosquito repellent essential oil is 0.2-0.5 mmol / (L·d), indicating that the mosquito repellent fiber ensures high temperature resistance and yarn strength while the microcapsules are not damaged and can release the mosquito repellent essential oil normally. At the same time, the mosquito repellent microcapsule particles 3 are distributed inside the fiber, and the mosquito repellent essential oil does not come into direct contact with the skin, making it safer and more reliable to use.

[0038] In this embodiment, the microcapsule particles 3 are spherical nanoparticles with a particle size of 580 nm. The smaller the particles, the more conducive it is for the microcapsule particles 3 to be uniformly dispersed in the fiber without affecting the physical and chemical properties of the fiber itself. The particle size of the nanoparticles can be obtained by changing the emulsification rate according to the requirements. In this embodiment, the emulsification rate is 12000 rpm, and the particle size can reach 580 nm.

[0039] In this embodiment, the microcapsules are prepared by in-situ polymerization. This method utilizes the monomers to undergo a polycondensation reaction on the surface of the core material under the action of catalysts, initiators, emulsifiers and other auxiliaries. Through cross-linking and polymerization, a film-like substance is formed to coat the core material, thereby forming a phase change microcapsule material. The preparation method has mild reaction conditions and simple process. The microcapsules prepared in this embodiment have good high temperature resistance, and the decomposition temperature of the microcapsules is above 240°C. When applied to polyester resin, the microcapsules will not rupture during the high-temperature melting process.

[0040] In this embodiment, the mosquito repellent essential oil is an essential oil with added permethrin; permethrin is extracted from chrysanthemum plants, has a mosquito-repelling effect, but is non-toxic and odorless to humans, and can be used for the mosquito repellent function of textiles.

[0041] A method for preparing mosquito-repellent fiber includes the following steps:

[0042] Step 1, preparation of microcapsules: Mosquito repellent essential oil is dripped into a styrene-maleic anhydride aqueous solution and emulsified for 1 hour to obtain a mosquito repellent essential oil emulsion. Melamine and formaldehyde are mixed at a molar ratio of 1 / 4-1 / 2, and the pH is adjusted to 8.0-9.5. The temperature is controlled at 50℃-70℃, and the mixture is stirred continuously to prepare a transparent melamine-formaldehyde prepolymer solution. The melamine-formaldehyde prepolymer is then added to the mosquito repellent essential oil emulsion and reacted at 50℃-70℃ for 0.5-2 hours. After drying, microcapsules containing mosquito repellent essential oil are obtained.

[0043] Step 2, Preparation of microcapsule polyester resin chips: The polyester resin chips are crushed to obtain polyester resin powder. The microcapsule powder and polyester resin powder are mixed evenly in a certain proportion, with the microcapsule powder accounting for 0.5%-10% of the mass of the polyester resin powder. The mixture is then melt-extruded by a twin-screw extruder and granulated to obtain mosquito-repellent microcapsule polyester resin chips.

[0044] Step 3, Preparation of mosquito-repellent fibers: The microcapsule polyester resin chips obtained in Step 2 and polypropylene resin are melted separately through a twin-screw extruder, and then stretched through a two-component composite spinning machine and a drawing machine to obtain mosquito-repellent fibers; wherein, the melting temperature of polyester resin is 150℃-230℃, the spinneret temperature is 170℃-240℃, the melting temperature of polypropylene resin is 160℃-250℃, the spinneret temperature is 170℃-270℃, the drawing temperature is 70℃-110℃, and the total draw ratio is 2-5 times.

[0045] In this embodiment, the skin layer 2 is made of low-melting-point polyester resin with a melting point of 190℃, and the core layer 1 is made of high-temperature pure polypropylene. The melt spinning process parameters are as follows: for the skin layer 2, the screw zone 1 temperature is 195℃, the screw zone 2 temperature is 210℃, the screw zone 3 temperature is 210℃, the screw zone 4 temperature is 215℃, and the spinneret temperature is 230℃; for the core layer 1, the screw zone 1 temperature is 250℃, the screw zone 2 temperature is 260℃, the screw zone 3 temperature is 265℃, the screw zone 4 temperature is 255℃, and the spinneret temperature is 250℃; the spinning speed is 800m / min, and the draw ratio is 3-4 times.

[0046] In this embodiment, the low-melting-point polyester resin is selected from the products of Xiamen Luyi Color Masterbatch Co., Ltd.

[0047] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the conditions in the embodiments shall be performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the reagents or instruments used are all conventional products that can be purchased commercially.

[0048] The following methods were used to test the performance of the obtained samples in the examples:

[0049] The test method for the mosquito-repellent performance of composite fibers shall be carried out in accordance with the standard GB / T 30126-2013;

[0050] The test method for the soap resistance of composite fibers shall be carried out in accordance with the standard GB / T 3921-2008;

[0051] The method for testing the breaking strength of composite fibers is to use the C(XQ-1A) monofilament yarn tensile strength tester produced by Shanghai Kepu Applied Science Institute to measure the breaking strength of the fibers.

[0052] Example 1

[0053] Step 1, preparation of microcapsules: Permethrin was added dropwise to a styrene-maleic anhydride aqueous solution with pH=5-6 and emulsified for 1 hour to obtain a permethrin emulsion. Melamine and formaldehyde were mixed at a molar ratio of 1 / 4-1 / 2, and the pH was adjusted to 8.0-9.5. The temperature was controlled at 50℃-70℃, and the mixture was stirred continuously to prepare a transparent melamine-formaldehyde prepolymer solution. The melamine-formaldehyde prepolymer was then added to the mosquito repellent essential oil emulsion and reacted at 50℃-70℃ for 2 hours to obtain a permethrin microcapsule suspension. After neutralization, filtration, washing, and freeze-drying, the suspension was ready for use.

[0054] Step 2, Preparation of microcapsule polyester resin chips: The polyester resin chips are dried and pulverized to obtain polyester resin powder. 4% by mass of microcapsule powder is added and mixed evenly. The mixture is melted through a twin-screw extruder (temperature 200℃), cooled with water, and pelletized to obtain mosquito-repellent microcapsule polyester resin chips, which are then dried for later use.

[0055] Step 3, Preparation of mosquito-repellent fibers: 30% of the microcapsule polyester resin chips obtained in Step 2 and 70% of the polypropylene resin are melted separately through a twin-screw extruder, and then stretched through a two-component composite spinning machine and a drawing machine to obtain mosquito-repellent fibers; wherein, the melting temperature of polyester resin is 150℃-230℃, the spinneret temperature is 230℃, the melting temperature of polypropylene resin is 160℃-250℃, the spinneret temperature is 250℃, the drawing temperature is 70℃-110℃, and the total drawing ratio is 3 times.

[0056] In this embodiment, the prepared mosquito-repellent fiber has a breaking strength of 2.0 cN / dtex, a mosquito repellency effect of grade B, and can withstand 10 washes.

[0057] Example 2

[0058] Unlike Example 1, in this example, the mosquito-repellent microcapsules contain 40% polyester resin chips and 60% polypropylene resin.

[0059] Step 1, Preparation of microcapsules: Permethrin was added dropwise to a styrene-maleic anhydride aqueous solution with pH=5-6 and emulsified for 1 hour to obtain a permethrin emulsion. Melamine and formaldehyde were mixed at a molar ratio of 1 / 4-1 / 2 to adjust the pH to 8.0-9.5, and the temperature was controlled at 50℃-70℃ while continuously stirring to prepare a transparent melamine-formaldehyde prepolymer solution. The melamine-formaldehyde prepolymer was then added to the mosquito repellent essential oil emulsion and reacted at 50℃-70℃ for 2 hours to obtain a permethrin microcapsule suspension. After neutralization, filtration, washing, and freeze-drying, the suspension was ready for use.

[0060] Step 2, Preparation of microcapsule polyester resin chips: The polyester resin chips are dried and pulverized to obtain polyester resin powder. 4% by mass of microcapsule powder is added and mixed evenly. The mixture is melted through a twin-screw extruder (temperature 200℃), cooled with water, and pelletized to obtain mosquito-repellent microcapsule polyester resin chips, which are then dried for later use.

[0061] Step 3, Preparation of mosquito-repellent composite fiber: 40% of the mosquito-repellent microcapsule polyester resin chips and 60% of the polypropylene resin obtained in Step 2 are melted separately through a twin-screw extruder, and then stretched through a two-component composite spinning machine and a drawing machine to obtain mosquito-repellent fiber; wherein, the melting temperature of polyester resin is 150℃-230℃ and the spinneret temperature is 230℃, the melting temperature of polypropylene resin is 160℃-250℃ and the spinneret temperature is 250℃, the drawing temperature is 70℃-110℃, and the total draw ratio is 2.5 times.

[0062] In this embodiment, the prepared mosquito-repellent fiber has a breaking strength of 1.8 cN / dtex, a mosquito repellency effect of grade B, and can withstand 10 washes.

[0063] Example 3

[0064] Unlike Example 1, in this example, the microcapsule contains 50% polyester resin chips and 50% polypropylene resin.

[0065] Step 1, preparation of microcapsules: Permethrin was added dropwise to a styrene-maleic anhydride aqueous solution with pH=5-6 and emulsified for 1 hour to obtain a permethrin emulsion. Melamine and formaldehyde were mixed at a molar ratio of 1 / 4-1 / 2, and the pH was adjusted to 8.0-9.5. The temperature was controlled at 50℃-70℃, and the mixture was stirred continuously to prepare a transparent melamine-formaldehyde prepolymer solution. The melamine-formaldehyde prepolymer was then added to the mosquito repellent essential oil emulsion and reacted at 50℃-70℃ for 2 hours to obtain a permethrin microcapsule suspension. After neutralization, filtration, washing, and freeze-drying, the suspension was ready for use.

[0066] Step 2, Preparation of microcapsule polyester resin chips: The polyester resin chips are dried and pulverized to obtain polyester resin powder. 4% by mass of microcapsule powder is added and mixed evenly. The mixture is melted through a twin-screw extruder (temperature 200℃), cooled with water, and pelletized to obtain mosquito-repellent microcapsule polyester resin chips, which are then dried for later use.

[0067] Step 3, Preparation of mosquito-repellent fibers: 50% of the microcapsule polyester resin chips obtained in Step 2 and 50% of the polypropylene resin were melted separately through a twin-screw extruder, and then stretched through a two-component composite spinning machine and a drawing machine to obtain mosquito-repellent fibers; the melting temperature of polyester resin was 150℃-230℃, the spinneret temperature was 230℃, the melting temperature of polypropylene resin was 160℃-250℃, the spinneret temperature was 250℃, the drawing temperature was 70℃-110℃, and the total draw ratio was 2 times.

[0068] In this embodiment, the prepared mosquito-repellent fiber has a breaking strength of 1.6 cN / dtex, a mosquito repellency effect of grade B, and can withstand 10 washes.

[0069] As can be seen from the above three embodiments, the mosquito-repellent fiber is prepared by blending polyester resin with mosquito-repellent microcapsules to obtain mosquito-repellent polyester resin chips, and then using mosquito-repellent polyester resin as the sheath and polypropylene resin as the core layer through melt spinning. Since the mosquito-repellent essential oil is in the sheath, it is more conducive to the diffusion of the mosquito-repellent essential oil to the fiber surface. At the same time, the use of mosquito-repellent microcapsule particles ensures that the mosquito-repellent essential oil is not destroyed during the high-temperature melting process. The mosquito repellency effect can reach grade B, with excellent mosquito-repellent performance. It can withstand 10 washes, exhibiting good washing resistance. The breaking strength is above 1.6 cN / dtex. The mosquito-repellent fiber prepared by the sheath-core composite spinning method of this invention increases the fiber's draw ratio and the orientation of the molecular chains in the fiber, resulting in more intermolecular bonds forming inside the fiber and a smaller intermolecular distance, thereby improving the fiber's mechanical strength.

[0070] In this embodiment, the mosquito-repellent fiber is obtained by blending polyester resin with mosquito-repellent microcapsules to obtain mosquito-repellent polyester resin chips. The microcapsule powder and polyester resin powder are mixed in a certain proportion, extruded and granulated, and then melt-spun with low-melting-point polyester resin as the outer layer 2 and polypropylene as the core layer 1 to obtain mosquito-repellent composite fiber. The microcapsules have good high-temperature resistance, with a decomposition temperature above 240°C. When applied to polyester resin, the microcapsules will not rupture during the high-temperature melting process. During the high-temperature melting process, the mosquito-repellent essential oil in the microcapsules can only diffuse out through the pores of the shell melamine resin. The limited pores make the diffusion of the mosquito-repellent essential oil very slow at high temperatures. A large amount of mosquito repellent essential oil is retained inside the microcapsules in the polyester resin. Through melt extrusion, the mosquito-repellent microcapsules are distributed in the fiber, and the mosquito-repellent essential oil diffuses out at room temperature to achieve the mosquito-repellent effect. The mosquito-repellent fiber has good airtightness of the microcapsule shell and excellent heat insulation performance during the high-temperature preparation process, with little loss of mosquito-repellent essential oil. It has the advantages of low cost, long mosquito-repellent cycle, good mosquito-repellent effect, and fast fiber spinning rate.

[0071] This invention provides a mosquito-repellent fiber and its preparation method. The mosquito-repellent microcapsules are simple to prepare. During the high-temperature preparation process, the microcapsule shell of the mosquito-repellent fiber has good airtightness, excellent heat insulation performance, and minimal loss of mosquito-repellent essential oil, resulting in excellent mosquito-repellent performance.

[0072] The descriptions of the foregoing specification and embodiments are used to explain the scope of protection of the present invention, but do not constitute a limitation on the scope of protection of the present invention. Modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or some of its technical features that can be obtained by those skilled in the art through logical analysis, reasoning, or limited experimentation, based on the teachings of the present invention or the foregoing embodiments, in conjunction with common general knowledge, ordinary technical knowledge in the art, and / or existing technology, should all be included within the scope of protection of the present invention.

Claims

1. An anti-mosquito fiber, characterized by, It is a round core-sheath structure, which comprises a core layer (1) and a sheath layer (2) covering the periphery of the core layer (1); the core layer (1) is pure polypropylene resin, and the sheath layer (2) is low-melting-point polyester resin containing mosquito repellent oil microcapsule particles (3) with a melting point of 150-230℃; the microcapsule particles (3) are uniformly distributed in the sheath layer (2) and have a dense resin as a wall material; the content ratio of the core layer (1) to the sheath layer (2) is 30%-80% for the core layer (1) and 20%-70% for the sheath layer (2) by mass percentage.

2. The anti-mosquito fiber according to claim 1, wherein the anti-mosquito fiber is characterized by, The content of the microcapsule particles (3) in the sheath layer (2) is 0.5%-10% of the polyester resin, and the loading rate of the mosquito repellent oil in the microcapsule particles (3) is 30%-60%.

3. The anti-mosquito fiber according to claim 2, wherein the anti-mosquito fiber is characterized by, The microcapsule particles (3) are prepared with the mosquito repellent oil as a core material.

4. An anti-mosquito fiber according to claim 3, wherein the anti-mosquito fiber is characterized by The initial release rate of the mosquito repellent oil is 0.2-0.5 mmol / (L·d) when extracted with methanol as a solvent.

5. The anti-mosquito fiber according to claim 4, wherein the anti-mosquito fiber is characterized by, The microcapsule particles (3) are spherical nanoparticles with a particle size of 580 nm.

6. An anti-mosquito fiber according to claim 5, wherein the polyethylene terephthalate is a polyethylene terephthalate glycol. The microcapsule is prepared by in-situ polymerization.

7. The anti-mosquito fiber according to claim 2, wherein the anti-mosquito fiber is characterized by, The mosquito repellent oil is an oil containing permethrin.

8. A process for the production of a mosquito repellent fiber as claimed in any one of claims 1 to 7, characterized by, The method comprises the following steps: Step 1: Preparation of microcapsules: mosquito repellent oil is dropped into a pH 5-6 aqueous solution of styrene maleic anhydride for emulsification for 1 hour to obtain a mosquito repellent oil emulsion; melamine and formaldehyde are mixed in a molar ratio of 1 / 4-1 / 2, the pH is adjusted to 8.0-9.5, the temperature is controlled at 50-70℃, and continuous stirring is performed to prepare a transparent melamine formaldehyde prepolymer solution; then the melamine formaldehyde prepolymer is added to the mosquito repellent oil emulsion, and the reaction is carried out at 50-70℃ for 0.5-2 hours, followed by drying to obtain mosquito repellent oil-containing microcapsules; Step 2: Preparation of polyester resin microcapsule chips: low-melting-point polyester resin powder is obtained by crushing polyester resin chips, and the microcapsule powder and the polyester resin powder are uniformly mixed in a proportion of 0.5%-10% of the microcapsule powder based on the mass percentage of the polyester resin powder; the mixture is subjected to double-screw melt extrusion and pelletization to obtain mosquito repellent polyester resin microcapsule chips; Step 3: Preparation of mosquito repellent fibers: the polyester resin microcapsule chips prepared in step 2 and pure polypropylene resin are respectively subjected to melt extrusion through a double-screw extruder, and then stretched through a double-component composite spinning machine and a drawing machine to obtain mosquito repellent fibers; wherein the melt temperature of the polyester resin is 150-230℃, the spinneret temperature is 170-240℃, the melt temperature of the polypropylene resin is 160-250℃, the spinneret temperature is 170-270℃, the drawing temperature is 70-110℃, and the total drawing multiple is 2-5.

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