Flame-retardant weather-resistant polyester fiber and preparation process thereof

Abstract

The invention discloses a flame-retardant weather-resistant polyester fiber and a preparation process thereof. The polyester fiber sequentially comprises a fiber core body, a self-adjusting functional layer and an outer protective layer from inside to outside, wherein the fiber core body is obtained by melt spinning of a mixture of loaded microspheres and polyester chips, and the loaded microspheres are mesoporous silica loaded with an antioxidant; the self-adjusting functional layer is obtained by dipping the fiber core body in a self-adjusting functional layer finishing liquid, and the outer protective layer is obtained by coating the self-adjusting functional layer with an outer protective layer coating and then curing. The polyester fiber (commonly known as polyester) is of a multi-layer structure formed by compounding the fiber core body, the self-adjusting functional layer and the outer protective layer, the polyester fiber is endowed with excellent weather resistance, flame retardance and mechanical strength through compounding of the multi-layer structure, the application scene of the polyester fiber can be widened, and the application effect of the polyester fiber can be improved.

Description

Technical Field

[0001] This invention relates to the field of polyester fibers, and in particular to a flame-retardant and weather-resistant polyester fiber and its preparation process. Background Technology

[0002] Polyester fiber (commonly known as polyester) refers to polyethylene terephthalate (PET) fiber. It boasts excellent properties and a wide range of applications. However, when used in outdoor settings (such as car covers, awnings, tents and sunshades, outdoor advertising products, outdoor decorative products, etc.), polyester fiber is prone to aging under harsh environmental conditions such as prolonged exposure to ultraviolet light, humidity, and oxygen. This leads to problems like brittleness, deterioration of mechanical properties, yellowing, and surface cracking, severely impacting its service life and performance. To improve the weather resistance of polyester fiber, the industry typically adds antioxidants, UV stabilizers, and other additives. Examples include a light-stabilized weather-resistant masterbatch for polyester fiber disclosed in patent CN103709669A, a wear-resistant and high-temperature resistant polyester fiber and its preparation method disclosed in CN120905796A, a black flame-retardant polyester FDY filament and its production method disclosed in CN104831402A, and a multi-purpose polyester fiber and its preparation method disclosed in CN103590135B. However, in conventional addition methods, antioxidants and UV stabilizers are prone to premature failure due to surface migration, aggregation, and insufficient stability, resulting in poor protective efficiency and duration, making it difficult to provide long-lasting weather resistance for polyester fibers.

[0003] On the other hand, polyester fiber is a flammable fiber, and to improve its safety, flame retardants are usually added to enhance its flame-retardant properties. Magnesium hydroxide is an excellent inorganic flame retardant and is widely used in polyester fibers, such as in the polyester textured yarn and its production method disclosed in patent CN113774668B, and the multifunctional nano-polyester fiber disclosed in CN103710963A. However, the poor compatibility of magnesium hydroxide with the polyester system limits its flame-retardant and reinforcing effects.

[0004] Therefore, it is now necessary to improve existing technologies to provide more reliable solutions. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a flame-retardant and weather-resistant polyester fiber and its preparation process, in order to address the shortcomings of the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a flame-retardant and weather-resistant polyester fiber, comprising, from the inside out, a fiber core, a self-regulating functional layer, and an outer protective layer. The fiber core is obtained by melt spinning a mixture of loaded microspheres and polyester chips, wherein the loaded microspheres are mesoporous silica loaded with antioxidants and ultraviolet absorbers. The self-regulating functional layer is obtained by impregnating the fiber core in a self-regulating functional layer finishing solution. The preparation method of the self-regulating functional layer finishing solution is as follows: hollow expandable microspheres, modified nano mica sheets, and modified flake magnesium hydroxide are added and dispersed in deionized water, dopamine is added, and the pH is adjusted to alkaline to obtain the self-regulating functional layer finishing solution. The outer protective layer is obtained by coating the self-regulating functional layer with an outer protective layer coating and then curing it. The raw materials of the outer protective layer coating include, by weight, 50-90 parts of epoxy resin, 25-45 parts of curing agent, 0.5-1.5 parts of antioxidant, 0.3-1.2 parts of ultraviolet absorber, and 2-8 parts of silane coupling agent.

[0007] Preferably, the mass ratio of loaded microspheres to polyester chips is 4-16:100; The preparation method of loaded microspheres is as follows: mesoporous silica is added to an additive impregnation solution containing antioxidants and ultraviolet absorbers, stirred under heating, then shaken on a shaker at room temperature, filtered, washed, and vacuum dried to obtain mesoporous silica loaded with additives, i.e., loaded microspheres.

[0008] Preferably, the hollow expandable microspheres are prepared by the following method: styrene, divinylbenzene, acrylonitrile, methyl methacrylate, and butyl acrylate are mixed to obtain a monomer mixture; SiO2 microspheres, CTAB, and ammonium persulfate are added to deionized water and ultrasonically dispersed under nitrogen gas; the monomer mixture is added dropwise to the resulting dispersion under stirring; the reaction is carried out under nitrogen protection; after the reaction is completed, the mixture is centrifuged, washed, and the solid product is added to an HF aqueous solution, stirred, filtered, washed, and dried to obtain the hollow expandable microspheres.

[0009] Preferably, the particle size of the SiO2 microspheres is 200-800 nm. Preferably, the preparation method of the self-regulating functional layer finishing solution is as follows: hollow expandable microspheres, modified nano mica sheets, and modified flake magnesium hydroxide are added and dispersed in deionized water, dopamine is added, and the pH is adjusted to alkaline to obtain the self-regulating functional layer finishing solution.

[0010] Preferably, the antioxidant is selected from at least one of antioxidant DLTDP, antioxidant DLTP, antioxidant DSTP, antioxidant 1010, and antioxidant 168; more preferably, it is antioxidant DLTDP.

[0011] Preferably, the ultraviolet absorber is selected from at least one of UV-327, UV-P, UV531, and UV326; more preferably, it is UV-327.

[0012] Preferably, the epoxy resin is epoxy resin E44, the curing agent is phthalic anhydride, and the silane coupling agent is KH-560.

[0013] The present invention also provides a preparation process for the flame-retardant and weather-resistant polyester fiber as described above, comprising the following steps: S1-1, Preparation of loaded microspheres: Mesoporous silica was added to an additive impregnation solution containing antioxidants and ultraviolet absorbers, stirred under heating, then shaken on a shaker at room temperature, filtered, washed, and vacuum dried to obtain loaded microspheres. S1-2. Polyester chips are mixed with loaded microspheres, then melt-extruded, and the resulting melt is spun to obtain a fiber core. S2. A self-regulating functional layer is coated onto the fiber core to obtain the fiber intermediate: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add flake magnesium hydroxide or nano mica flakes to deionized water, disperse by ultrasonication, add stearic acid aqueous solution dropwise under stirring, heat and stir, filter, wash, and dry to obtain modified flake magnesium hydroxide or nano mica flakes. S2-2, Preparation of hollow expandable microspheres: S2-2-1. Styrene, divinylbenzene, acrylonitrile, methyl methacrylate, and butyl acrylate are mixed to obtain a monomer mixture; S2-2-2, SiO2 microspheres, CTAB, and ammonium persulfate were added to deionized water and ultrasonically dispersed under nitrogen. The monomer mixture was added dropwise to the resulting dispersion under stirring and heated under nitrogen protection. After the reaction was completed, the mixture was centrifuged, washed, and the solid product was added to an HF aqueous solution. The mixture was stirred, filtered, washed, and dried to obtain hollow expandable microspheres. S2-3. Hollow expandable microspheres, modified nano mica sheets, and modified flake magnesium hydroxide are added and dispersed in deionized water. Dopamine is added and the pH is adjusted to alkaline to obtain a self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, remove it and vacuum dry it to obtain the fiber intermediate. S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 50-90 parts of epoxy resin, 25-45 parts of curing agent, 0.5-1.5 parts of antioxidant, 0.3-1.2 parts of UV absorber, and 2-8 parts of silane coupling agent are mixed and stirred evenly to obtain an outer protective coating. The outer protective coating is applied to the surface of the fiber intermediate and cured by heating to obtain the flame-retardant and weather-resistant polyester fiber.

[0014] Preferably, step S1 specifically includes: S1-1, Preparation of loaded microspheres: Add 1-4g of mesoporous silica to 25-100mL of additive impregnation solution, stir at 40-60℃ for 2-8h, then shake on a shaker at room temperature for 6-24h, filter, wash, and dry to obtain loaded microspheres; wherein, the additive impregnation solution is a toluene solution containing 6-10mg / mL of antioxidant DLTDP and 2-8mg / mL of ultraviolet absorber UV-327; S1-2. Mix 100 parts by weight of pre-dried polyester chips with 4-16 parts by weight of loaded microspheres, and then melt-extrude at 235-260℃. The resulting melt is spun to obtain a fiber core.

[0015] Preferably, step S2 specifically includes: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add 2.5-10g of flake magnesium hydroxide or nano mica flakes to 75-300mL of deionized water, ultrasonically disperse for 0.5-2h, add 5-20mL of stearic acid aqueous solution with a concentration of 1-5mg / mL dropwise while stirring, stir at 70-90℃ for 45-180min, filter, wash, and dry to obtain modified flake magnesium hydroxide or nano mica flakes; S2-2, Preparation of hollow expandable microspheres: S2-2-1. Mix 2.1-8.4g styrene, 0.5-2g divinylbenzene, 1.25-5g acrylonitrile, 0.6-2.5g methyl methacrylate, and 1-4g butyl acrylate to obtain a monomer mixture. S2-2-2: Add 0.25-1g of SiO2 microspheres with a particle size of 200-800nm, 0.6-2.5g of CTAB, and 0.15-0.6g of ammonium persulfate to 60-250mL of deionized water, and ultrasonically disperse under nitrogen for 30-90min. Add the monomer mixture dropwise to the resulting dispersion while stirring. Under nitrogen protection, react at 60-70℃ for 6-12h. Centrifuge, wash the solid product with deionized water, and then add it to 50-200mL of HF aqueous solution with a concentration of 15-40wt%. Stir at 30-50℃ for 3-8h, filter, wash, and dry to obtain hollow expandable microspheres. S2-3. Take 0.125-0.5g of hollow expandable microspheres, 0.25-1g of modified nano-mica sheets, and 0.3-1.6g of modified flake magnesium hydroxide and add them to 75-300mL of deionized water. Disperse the mixture by ultrasonication for 0.5-2h. Then add 0.75-3g of dopamine and stir for 30-90min. Adjust the pH value to 8-10 with 0.05-0.2mol / L NaOH solution and stir for 15-60min to obtain the self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, controlling the mass ratio of fiber core to self-regulating functional layer finishing solution to 1:8-15. Immerse at 30-50℃ for 10-40 minutes, then remove and vacuum dry at 50-75℃ for 6-10 hours to complete one immersion treatment. Repeat the immersion 2-5 times to obtain the fiber intermediate.

[0016] Preferably, step S3 specifically includes: By weight, 50-90 parts epoxy resin, 25-45 parts curing agent, 0.5-1.5 parts antioxidant, 0.3-1.2 parts UV absorber, and 2-8 parts silane coupling agent are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 40-80 g / m². 2 The flame-retardant and weather-resistant polyester fiber is obtained by curing at 100-140℃ for 1.5-5 hours.

[0017] Preferably, the preparation process of the flame-retardant and weather-resistant polyester fiber includes the following steps: S1. Preparation of fiber core: S1-1, Preparation of loaded microspheres: 2g of mesoporous silica was added to 50mL of additive impregnation solution, stirred at 50℃ for 4h, then shaken on a shaker at room temperature for 12h, filtered, washed, and dried to obtain loaded microspheres; wherein, the additive impregnation solution was a toluene solution containing 8mg / mL of antioxidant DLTDP and 5mg / mL of ultraviolet absorber UV-327. S1-2. Mix 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours with 8 parts by weight of loaded microspheres, and then melt extrude at 245°C. The resulting melt is spun to obtain a fiber core. S2. A self-regulating functional layer is coated onto the fiber core to obtain the fiber intermediate: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add 5g of flake magnesium hydroxide or nano mica flakes to 150mL of deionized water and ultrasonically disperse for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.5mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and dry to obtain modified flake magnesium hydroxide or nano mica flakes. S2-2, Preparation of hollow expandable microspheres: S2-2-1. Mix 4.2g styrene, 1.0g divinylbenzene, 2.5g acrylonitrile, 1.25g methyl methacrylate and 2g butyl acrylate to obtain a monomer mixture; S2-2-2: 0.5g of SiO2 microspheres with a particle size of 200-800nm, 0.125g of CTAB, and 0.3g of ammonium persulfate were added to 120mL of deionized water and ultrasonically dispersed under nitrogen for 45min. The monomer mixture was added dropwise to the resulting dispersion under stirring. The reaction was carried out under nitrogen protection at 65℃ for 8h. After centrifugation, the solid product was washed with deionized water and then added to 100mL of 30wt% HF aqueous solution. The mixture was stirred at 40℃ for 5h, filtered, washed, and dried to obtain hollow expandable microspheres. S2-3. Take 0.25g of hollow expandable microspheres, 0.35g of modified nano mica sheets, and 0.7g of modified flake magnesium hydroxide and add them to 150mL of deionized water. Disperse by ultrasonication for 1h, then add 2.0g of dopamine, stir for 45min, adjust the pH value to 9 with 0.1mol / L NaOH solution, stir for 30min, and obtain the self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, controlling the mass ratio of fiber core to self-regulating functional layer finishing solution to be 1:10. Immerse at 40℃ for 20 min, then remove and vacuum dry at 60℃ for 8 h to complete one immersion treatment. Repeat the immersion 3 times to obtain the fiber intermediate. S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 70 parts epoxy resin, 35 parts curing agent, 0.75 parts antioxidant, 0.6 parts UV absorber, and 4 parts silane coupling agent are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 60 g / m². 2 The flame-retardant and weather-resistant polyester fiber was obtained by curing at 120°C for 2.5 hours.

[0018] Invention Mechanism: The flame-retardant and weather-resistant polyester fiber provided by the present invention has a multi-layer composite structure, which includes a fiber core, a self-regulating functional layer and an outer protective layer from the inside to the outside. The working mechanism of each layer is explained in detail below.

[0019] 1. Antioxidants and UV absorbers are loaded with mesoporous silica within the fiber core, enabling long-term sustained release of antioxidants and UV absorbers, thus providing longer-lasting weather protection. The loading of mesoporous silica reduces the direct contact between antioxidants and the polyester fiber matrix, decreasing the outward diffusion of antioxidants and UV absorbers and preventing their failure, thereby extending the effective duration of antioxidants and UV absorbers.

[0020] 2. The outer protective layer is the outermost layer, and its main resin is epoxy resin. Epoxy resin has good adhesion and can form a dense protective layer, providing good physical insulation and improving resistance to thermo-oxidative aging and ultraviolet radiation, thereby improving the weather resistance of polyester fibers. At the same time, the outer protective layer can also improve the toughness, abrasion resistance, and corrosion resistance of polyester fibers. Ultimately, it can extend the service life of polyester fibers.

[0021] 3. The self-regulating functional layer is composed of hollow expandable microspheres, modified nano-mica sheets, modified sheet-like magnesium hydroxide, and dopamine. Dopamine forms a film through self-polymerization, while nano-mica sheets and sheet-like magnesium hydroxide act as sheet-like fillers within the polydopamine film, forming a scaly coating structure. The hollow expandable microspheres are uniformly dispersed within the self-regulating functional layer, enabling the "self-regulating open-close" function of the additive release channels within the scaly coating structure. This "open-close" function is reversible; specifically, when the ambient temperature rises, the hollow expandable microspheres undergo thermal expansion (although the self-regulating functional layer as a whole also undergoes thermal expansion when the ambient temperature rises, the expansion coefficient of the hollow expandable microspheres is significantly higher than that of the main body of the self-regulating functional layer, thus resulting in expansion). The significant difference in expansion ratio creates gaps between the scales and the self-regulating functional layer, thus expanding the scales (nano-mica flakes and flake magnesium hydroxide) in the scaly coating structure. This increases the gaps between the scales, opening or widening the release channels for antioxidants and ultraviolet absorbers (collectively referred to as additives; this gap is defined as the additive release channel). This allows the internal additives to be released and diffused outward more quickly. The additives then pass through the self-regulating functional layer into the outer protective layer, providing antioxidant and UV protection. When the ambient temperature decreases, the hollow expandable microspheres shrink and recover, reducing the gaps between the scales and narrowing or closing the additive release channels. This prevents the additives from diffusing and migrating outward, thus avoiding failure and waste, and extending the duration of their effect.

[0022] When the ambient temperature rises, the damaging effect of thermo-oxidative aging on the outer protective layer will increase (at high temperatures, the molecular structure in epoxy resin is more likely to react with oxygen in the environment, leading to structural chain breakage, epoxy resin decomposition, and ultimately a decrease in the strength and mechanical properties of the outer protective layer, resulting in the loss of protection for the internal fiber core). In many outdoor applications, the temperature rise is usually caused by sunlight, so the intensity of ultraviolet radiation is also likely to increase. In other words, for most outdoor applications of the polyester fiber of this invention, the rise in ambient temperature and the increase in ultraviolet radiation are usually simultaneous. Therefore, more antioxidants are needed to remove oxidants from the outer protective layer and more ultraviolet absorbers are needed to absorb ultraviolet radiation. The self-regulating functional layer releases more antioxidants and ultraviolet absorbers by opening / expanding the auxiliary agent release channels, which can meet the needs at this time. Moreover, the higher the ambient temperature (the stronger the ultraviolet radiation, the higher the temperature will be), the larger the hollow expandable microspheres will expand, the larger the gap between the scales will be, and the greater the release rate of antioxidants and ultraviolet absorbers will be, thereby realizing the self-regulating function of antioxidant and ultraviolet absorber supply. Therefore, by combining the fiber core with the self-regulating functional layer, the supply of antioxidants and ultraviolet absorbers can be adaptively adjusted according to the ambient temperature. This effect can meet the functional requirements of the outer protective layer for antioxidant and ultraviolet protection when the environment changes.

[0023] The outer protective layer contains a certain amount of antioxidants and UV absorbers, which provide initial antioxidant and UV protection for the epoxy resin in the outer protective layer. The fiber core acts as a backup storage for antioxidants and UV absorbers. During the use of polyester fibers, as the antioxidants and UV absorbers in the outer protective layer are gradually consumed, the antioxidants and UV absorbers stored in the fiber core are gradually released under the action of the self-regulating functional layer, providing antioxidants and UV absorbers to the outer protective layer. This staged release strategy and the structural design with a self-regulating release rate enable it to improve the utilization rate of antioxidants and UV absorbers, achieve longer-lasting antioxidant and UV protection effects, and thus significantly improve the weather resistance of polyester fibers.

[0024] In the preparation of the self-regulating functional layer, hollow expandable microspheres, modified nano-mica sheets, modified flake magnesium hydroxide, and dopamine are first mixed in an alkaline environment as a finishing solution for the self-regulating functional layer. Dopamine has high adhesion and reactivity and will self-polymerize into a film in an alkaline environment. After the three fillers, hollow expandable microspheres, modified nano-mica sheets, and modified flake magnesium hydroxide, are mixed with dopamine, dopamine will adsorb onto the three fillers to form a film. Then, the fiber core is immersed in the self-regulating functional layer finishing solution, and dopamine can adhere to the fiber core to form a film. At the same time, the hollow expandable microspheres, modified nano-mica sheets, and modified flake magnesium hydroxide are also firmly adhered to the fiber core, thus forming a self-regulating functional layer in which the three fillers, hollow expandable microspheres, modified nano-mica sheets, and modified flake magnesium hydroxide, are uniformly doped and filled, and polydopamine is the main film-forming agent.

[0025] In the self-regulating functional layer, the abundant modified nano-mica sheets and modified flake magnesium hydroxide are pre-treated with stearic acid using the same method, which improves their dispersibility. The modified nano-mica sheets and modified flake magnesium hydroxide also have the following functions in the polyester fiber system: (1) Modified nano mica sheets: Mica sheets themselves have high temperature resistance. The sheet-like structure of mica sheets can be used as a filler and reinforcing component to improve the strength of the self-regulating functional layer. At the same time, mica sheets help to improve the heat resistance and dimensional stability of the self-regulating functional layer at high temperatures. Its heat insulation and shielding properties also help to improve flame retardant properties. Furthermore, mica sheets can also shield ultraviolet rays and improve weather resistance.

[0026] (2) Magnesium hydroxide is an excellent inorganic flame retardant, and its addition can significantly improve the flame retardant performance of polyester fiber system. The flake magnesium hydroxide used in this invention can reduce the agglomeration between magnesium hydroxide particles, which is conducive to achieving uniform dispersion, thereby playing a better flame retardant effect. In addition, the flake magnesium hydroxide can also improve the strength of the self-regulating functional layer.

[0027] In this invention, modified nano-mica flakes and modified flake magnesium hydroxide exist in the polyester fiber system in the form of uniform coating on the fiber core. While forming a scale-like coating structure of a self-regulating functional layer, it can also achieve uniform dispersion of the two inorganic materials, overcome their tendency to agglomerate in the polyester fiber system, and play a synergistic role in improving flame retardant performance.

[0028] The beneficial effects of this invention are: This invention provides a flame-retardant and weather-resistant polyester fiber and its preparation process. The polyester fiber of this invention has a multi-layer structure composed of a fiber core, a self-regulating functional layer and an outer protective layer. This multi-layer structure endows the polyester fiber with excellent weather resistance, flame retardancy and mechanical strength, which can broaden its application scenarios and improve its application effect. In the polyester fiber of the present invention, antioxidants and ultraviolet absorbers are loaded with mesoporous silica in the fiber core, which can achieve long-term sustained release of antioxidants and ultraviolet absorbers, thereby providing a longer-lasting weather protection effect. In the polyester fiber of the present invention, the outer protective layer with epoxy resin as the main body plays a good physical barrier role, which can improve the resistance to thermo-oxidative aging and UV resistance, improve the weather resistance of polyester fiber, and at the same time, the outer protective layer can also improve the toughness, wear resistance and corrosion resistance of polyester fiber. In the polyester fiber of this invention, the self-regulating functional layer is obtained by coating hollow expandable microspheres, modified nano-mica sheets, modified flake magnesium hydroxide, and dopamine. The nano-mica sheets and flake magnesium hydroxide, as flake fillers, fill the polydopamine film to form a scaly coating layer structure. This structure enables adaptive supply of antioxidants and ultraviolet absorbers: when the ambient temperature rises, the hollow expandable microspheres thermally expand, thereby opening the scales (nano-mica sheets and flake magnesium hydroxide) in the scaly coating layer structure, increasing the gaps between the scales, and opening or expanding the release channels for antioxidants and ultraviolet absorbers. This allows the internal antioxidants and ultraviolet absorbers to be released more quickly. The antioxidants and ultraviolet absorbers, through self-regulating function... The energy layer penetrates into the outer protective layer, providing it with stronger antioxidant and UV protection functions. This perfectly addresses the increased demand for antioxidants and UV absorbers under high-temperature environments. Therefore, this invention provides a novel strategy and structure for adjusting the release of additives (antioxidants and UV absorbers) through the cooperation of the self-regulating functional layer and the loaded micro-particles in the fiber core. On the other hand, modified nano-mica sheets and modified flake magnesium hydroxide exist in the polyester fiber system in a uniformly coated form to form a self-regulating functional layer. This enables the uniform dispersion of the two inorganic materials, overcoming their tendency to agglomerate in the polyester fiber system. It also has a synergistic effect in improving flame retardant performance and can enhance the strength of the self-regulating functional layer. Attached Figure Description

[0029] Figure 1 The average particle size of the hollow expandable microspheres prepared in Example 1 was measured at different temperatures. Figure 2 The XRD pattern of the self-regulating functional layer in Example 1; Figure 3 Antioxidant release curves for the fiber intermediates prepared in Examples 1, 2, and 2; Figure 4 The fracture strength test results are for Examples 1-3 and Comparative Examples 1-5; Figure 5 The results of the heat and oxygen aging resistance tests for Examples 1-3 and Comparative Examples 1-5 are shown. Figure 6The limiting oxygen index test results are for Examples 1-3 and Comparative Examples 1-5. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0031] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0033] The following examples and comparative examples describe the sources of the main raw materials. 1. Mesoporous silica can be obtained from conventional commercially available products or can be prepared in-house. In this invention, it is prepared using the following conventional method: Add 0.5 g of cetylammonium bromide and 50 mL of ethanol to 80 mL of deionized water, then add 2 mL of 22 wt% ammonia water, stir for 20 min, add 5 mL of tetraethyl orthosilicate dropwise, stir at room temperature for 6 h, let stand for 2 h, filter, wash with deionized water, dry at 70 °C for 6 h, and then calcine at 600 °C for 3 h in a muffle furnace to obtain mesoporous silica.

[0034] 2. Flake magnesium hydroxide Flake magnesium hydroxide can be obtained from commercially available products or can be prepared in-house. In this invention, following the method described in the literature "Wu Yimei, Sun Yuzhu, Lu Guimin, et al. Preparation of hexagonal flake magnesium hydroxide by crystallization-hydrothermal method [J]. Journal of Chemical Engineering of Chinese Universities, 2019, 33(2):10.DOI:10.3969 / j.issn.1003-9015.2019.02.022.", the flake magnesium hydroxide is prepared in-house through the following steps: 125 mL of 3 mol / L sodium chloride solution and 150 mL of 2 mol / L MgCl2 solution were mixed and ultrasonically dispersed for 20 min. 180 mL of 2.5 mol / L NaOH solution was added dropwise to the resulting mixture while stirring at 500 rpm. The mixture was stirred at 80 °C and 1000 rpm for 90 min, centrifuged, and the solid product was added to 200 mL of 1 mol / L NaOH solution. The mixture was ultrasonically dispersed for 45 min, and the resulting mixture was transferred to a reaction vessel and reacted at 120 °C for 8 h. The mixture was then filtered, the filter cake was washed with deionized water, and vacuum dried at 100 °C for 12 h to obtain flake magnesium hydroxide.

[0035] 3. Nano-mica sheets The nano-mica sheets can be commercially available products or homemade. In this invention, the method described in the literature "Du Conghui. Preparation and Water Treatment Performance Study of Two-Dimensional Nano-Mica Sheet Membranes [D]. Shandong University [2025-12-06]" is followed to prepare the nano-mica sheets by the following steps: (1) Mica (mica: K2O∙3Al2O3∙6SiO2∙2H2O, 400 mesh, Shanghai Aladdin Biochemical Technology Co., Ltd.) was ground to below 10μm, heated at 800℃ for 1h, cooled to room temperature and added to 65wt% nitric acid, the solid content was controlled to be 5%, ultrasonically dispersed for 1h and then stirred and refluxed at 90℃ for 8h, filtered, washed with deionized water and dried at 90℃ to constant weight to obtain acid-treated mica powder; (2) Take 2g of acid-treated mica powder and 5g of CTAB and add them to 200mL of deionized water. Stir at 85℃ and 1000rpm for 24h, filter, wash with deionized water, and dry at 90℃ to constant weight to obtain pretreated mica powder. (3) Take 3g of pretreated mica powder and add it to a mixed solvent of 200mL ethanol and deionized water in a volume ratio of 1:1. Centrifuge at 950×g for 10min. Take the supernatant and centrifuge at 11000×g for 10min. Collect the precipitate, wash it with deionized water, and vacuum dry it at 90℃ to obtain nano mica sheets with a sheet diameter of about 400-450nm.

[0036] 4. Other commonly available raw materials Polyester chips (PET chips), Shanghai Yiqiang Plastics Technology Co., Ltd., brand: Changzhou Huarun, grade CR-8828; Styrene, Shanghai Aladdin Biochemical Technology Co., Ltd.; Divinylbenzene, Shanghai Aladdin Biochemical Technology Co., Ltd.; Acrylonitrile, Shanghai Aladdin Biochemical Technology Co., Ltd.; Methyl methacrylate, Shanghai Aladdin Biochemical Technology Co., Ltd.; Butyl acrylate, Shanghai Aladdin Biochemical Technology Co., Ltd.; SiO2 microspheres, average particle size 600nm, Suzhou Zhiyi Microsphere Technology Co., Ltd. Dopamine, Shanghai Aladdin Biochemical Technology Co., Ltd.; Epoxy resin E44, brand: Phoenix, Changzhou Lebang Composite Materials Co., Ltd. Phthalic anhydride, Shanghai Aladdin Biochemical Technology Co., Ltd.; Antioxidant DLTDP, Jiangsu Xinluda Polymer Materials Co., Ltd.; UV-327, an ultraviolet absorber, is produced by Jiangsu Xinluda Polymer Materials Co., Ltd. Example

[0037] A flame-retardant and weather-resistant polyester fiber comprises, from the inside out, a fiber core, a self-regulating functional layer, and an outer protective layer. Its preparation process includes the following steps: S1. Preparation of fiber core: S1-1, Preparation of loaded microspheres: Add 2g of mesoporous silica to 50mL of additive impregnation solution, stir at 50℃ for 4h, then shake on a shaker at room temperature for 12h, filter, wash the solid with toluene and ethanol in sequence, and vacuum dry at 50℃ overnight to obtain mesoporous silica loaded with additive, i.e., loaded microspheres. The impregnation solution for the additives is a toluene solution of antioxidant DLTDP and ultraviolet absorber UV-327, with the concentration of antioxidant DLTDP being 8 mg / mL and the concentration of ultraviolet absorber UV-327 being 5 mg / mL.

[0038] S1-2. 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours are mixed with 8 parts by weight of loaded microspheres and stirred for 45 minutes. The resulting mixture is added to a twin-screw extruder and melt-extruded at 245°C. The resulting melt is spun to obtain a fiber core. The spinning temperature is 260°C, the spinning speed is 600 m / min, the draw ratio is 2, and the stretching rate is 550 m / min.

[0039] S2. A self-regulating functional layer is coated onto the fiber core to obtain the fiber intermediate: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add 5g of flake magnesium hydroxide to 150mL of deionized water and sonicate for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.5mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and vacuum dry to constant weight to obtain modified flake magnesium hydroxide. Add 5g of nano-mica sheets to 150mL of deionized water and ultrasonically disperse for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.5mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and vacuum dry to constant weight to obtain modified nano-mica sheets. S2-2, Preparation of hollow expandable microspheres: S2-2-1. Mix 4.2g styrene, 1.0g divinylbenzene, 2.5g acrylonitrile, 1.25g methyl methacrylate and 2g butyl acrylate to obtain a monomer mixture; S2-2-2. 0.5g SiO2 microspheres, 0.125g CTAB, and 0.3g ammonium persulfate were added to 120mL of deionized water and ultrasonically dispersed under nitrogen for 45min. The monomer mixture was then added dropwise to the resulting dispersion under stirring. The mixture was reacted at 65℃ for 8h under nitrogen protection. After centrifugation, the solid product was washed with deionized water and then added to 100mL of 30wt% HF aqueous solution. The mixture was stirred at 40℃ for 5h, filtered, washed with deionized water, and vacuum dried at 60℃ to constant weight to obtain hollow expandable microspheres.

[0040] S2-3. Preparation of self-regulating functional layer finishing solution: Take 0.25g of hollow expandable microspheres, 0.35g of modified nano mica sheets, and 0.7g of modified flake magnesium hydroxide and add them to 150mL of deionized water. Disperse them by ultrasonication for 1h, then add 2.0g of dopamine and stir for 45min. Adjust the pH value to 9 with 0.1mol / L NaOH solution and stir for 30min to obtain the self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, controlling the mass ratio of fiber core to self-regulating functional layer finishing solution to 1:10. Immerse at 40℃ for 20 minutes, remove and vacuum dry at 60℃ for 8 hours to complete one immersion treatment. Repeat the immersion 3 times to obtain the fiber core coated with the self-regulating functional layer, i.e., the fiber intermediate.

[0041] S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 70 parts of epoxy resin E44, 35 parts of curing agent phthalic anhydride, 0.75 parts of antioxidant DLTDP, 0.6 parts of ultraviolet absorber UV-327, and 4 parts of silane coupling agent KH-560 are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 60 g / m². 2 The flame-retardant and weather-resistant polyester fiber was obtained by curing at 120℃ for 2.5 hours. Example

[0042] A flame-retardant and weather-resistant polyester fiber comprises, from the inside out, a fiber core, a self-regulating functional layer, and an outer protective layer. Its preparation process includes the following steps: S1. Preparation of fiber core: S1-1, Preparation of loaded microspheres: Add 2g of mesoporous silica to 50mL of additive impregnation solution, stir at 50℃ for 4h, then shake on a shaker at room temperature for 12h, filter, wash the solid with toluene and ethanol in sequence, and vacuum dry at 50℃ overnight to obtain mesoporous silica loaded with additive, i.e., loaded microspheres. The impregnation solution for the additives is a toluene solution of antioxidant DLTDP and ultraviolet absorber UV-327, with the concentration of antioxidant DLTDP being 8 mg / mL and the concentration of ultraviolet absorber UV-327 being 5 mg / mL.

[0043] S1-2. 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours are mixed with 8 parts by weight of loaded microspheres and stirred for 45 minutes. The resulting mixture is added to a twin-screw extruder and melt-extruded at 245°C. The resulting melt is spun to obtain a fiber core. The spinning temperature is 260°C, the spinning speed is 600 m / min, the draw ratio is 2, and the stretching rate is 550 m / min.

[0044] S2. A self-regulating functional layer is coated onto the fiber core to obtain the fiber intermediate: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add 5g of flake magnesium hydroxide to 150mL of deionized water and sonicate for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.5mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and vacuum dry to constant weight to obtain modified flake magnesium hydroxide. Add 5g of nano-mica sheets to 150mL of deionized water and ultrasonically disperse for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.5mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and vacuum dry to constant weight to obtain modified nano-mica sheets. S2-2, Preparation of hollow expandable microspheres: S2-2-1. Mix 4.2g styrene, 1.0g divinylbenzene, 2.5g acrylonitrile, 1.25g methyl methacrylate and 2g butyl acrylate to obtain a monomer mixture; S2-2-2. 0.5g SiO2 microspheres, 0.125g CTAB, and 0.3g ammonium persulfate were added to 120mL of deionized water and ultrasonically dispersed under nitrogen for 45min. The monomer mixture was then added dropwise to the resulting dispersion under stirring. The mixture was reacted at 65℃ for 8h under nitrogen protection. After centrifugation, the solid product was washed with deionized water and then added to 100mL of 30wt% HF aqueous solution. The mixture was stirred at 40℃ for 5h, filtered, washed with deionized water, and vacuum dried at 60℃ to constant weight to obtain hollow expandable microspheres.

[0045] S2-3. Preparation of self-regulating functional layer finishing solution: Take 0.30g of hollow expandable microspheres, 0.35g of modified nano mica sheets, and 0.7g of modified flake magnesium hydroxide and add them to 150mL of deionized water. Disperse by ultrasonication for 1h, then add 2.0g of dopamine, stir for 45min, adjust the pH value to 9 with 0.1mol / L NaOH solution, stir for 30min, and obtain the self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, controlling the mass ratio of fiber core to self-regulating functional layer finishing solution to 1:10. Immerse at 40℃ for 20 minutes, remove and vacuum dry at 60℃ for 8 hours to complete one immersion treatment. Repeat the immersion 3 times to obtain the fiber core coated with the self-regulating functional layer, i.e., the fiber intermediate.

[0046] S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 70 parts of epoxy resin E44, 35 parts of curing agent phthalic anhydride, 0.75 parts of antioxidant DLTDP, 0.6 parts of ultraviolet absorber UV-327, and 4 parts of silane coupling agent KH-560 are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 60 g / m². 2 The flame-retardant and weather-resistant polyester fiber was obtained by curing at 120℃ for 2.5 hours. Example

[0047] A flame-retardant and weather-resistant polyester fiber comprises, from the inside out, a fiber core, a self-regulating functional layer, and an outer protective layer. Its preparation process includes the following steps: S1. Preparation of fiber core: S1-1, Preparation of loaded microspheres: Add 2g of mesoporous silica to 50mL of additive impregnation solution, stir at 50℃ for 4h, then shake on a shaker at room temperature for 12h, filter, wash the solid with toluene and ethanol in sequence, and vacuum dry at 50℃ overnight to obtain mesoporous silica loaded with additive, i.e., loaded microspheres. The impregnation solution for the additives is a toluene solution of antioxidant DLTDP and ultraviolet absorber UV-327, with the concentration of antioxidant DLTDP being 8 mg / mL and the concentration of ultraviolet absorber UV-327 being 5 mg / mL.

[0048] S1-2. 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours are mixed with 8 parts by weight of loaded microspheres and stirred for 45 minutes. The resulting mixture is added to a twin-screw extruder and melt-extruded at 250°C. The resulting melt is spun to obtain a fiber core. The spinning temperature is 260°C, the spinning speed is 600 m / min, the draw ratio is 2, and the stretching rate is 550 m / min.

[0049] S2. A self-regulating functional layer is coated onto the fiber core to obtain the fiber intermediate: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add 5g of flake magnesium hydroxide to 150mL of deionized water and sonicate for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.2mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and vacuum dry to constant weight to obtain modified flake magnesium hydroxide. Add 5g of nano-mica sheets to 150mL of deionized water and ultrasonically disperse for 1h. Add 10mL of stearic acid aqueous solution with a concentration of 2.2mg / mL dropwise while stirring. Stir at 80℃ for 90min, filter, wash, and vacuum dry to constant weight to obtain modified nano-mica sheets. S2-2, Preparation of hollow expandable microspheres: S2-2-1. Mix 4.2g styrene, 1.5g divinylbenzene, 2.0g acrylonitrile, 1.25g methyl methacrylate and 1.8g butyl acrylate to obtain a monomer mixture; S2-2-2. 0.5g SiO2 microspheres, 0.125g CTAB, and 0.3g ammonium persulfate were added to 120mL of deionized water and ultrasonically dispersed under nitrogen for 45min. The monomer mixture was then added dropwise to the resulting dispersion under stirring. The mixture was reacted at 65℃ for 8h under nitrogen protection. After centrifugation, the solid product was washed with deionized water and then added to 100mL of 30wt% HF aqueous solution. The mixture was stirred at 40℃ for 5h, filtered, washed with deionized water, and vacuum dried at 60℃ to constant weight to obtain hollow expandable microspheres.

[0050] S2-3. Preparation of self-regulating functional layer finishing solution: Take 0.25g of hollow expandable microspheres, 0.35g of modified nano mica sheets, and 0.7g of modified flake magnesium hydroxide and add them to 150mL of deionized water. Disperse them by ultrasonication for 1h, then add 2.0g of dopamine and stir for 45min. Adjust the pH value to 9 with 0.1mol / L NaOH solution and stir for 30min to obtain the self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, controlling the mass ratio of fiber core to self-regulating functional layer finishing solution to 1:10. Immerse at 40℃ for 20 minutes, remove and vacuum dry at 60℃ for 8 hours to complete one immersion treatment. Repeat the immersion 3 times to obtain the fiber core coated with the self-regulating functional layer, i.e., the fiber intermediate.

[0051] S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 70 parts of epoxy resin E44, 35 parts of curing agent phthalic anhydride, 0.75 parts of antioxidant DLTDP, 0.6 parts of ultraviolet absorber UV-327, and 4 parts of silane coupling agent KH-560 are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 60 g / m². 2 The flame-retardant and weather-resistant polyester fiber was obtained by curing at 120℃ for 2.5 hours.

[0052] A flame-retardant and weather-resistant polyester fiber, comprising a fiber core and an outer protective layer from the inside out, is manufactured using the following steps: S1. Preparation of fiber core: S1-1. Preparation of loaded microspheres, the specific steps are the same as in Example 1; S1-2. 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours are mixed with 8 parts by weight of loaded microspheres, 15 parts by weight of modified flake magnesium hydroxide, and 7.5 parts by weight of modified nano-mica flakes. The mixture is stirred for 45 minutes. The resulting mixture is added to a twin-screw extruder and melt-extruded at 245°C. The resulting melt is spun to obtain a fiber core. The spinning temperature is 260°C, the spinning speed is 600 m / min, the draw ratio is 2, and the stretching rate is 550 m / min.

[0053] S2. Cover the fiber core with an outer protective layer: By weight, 70 parts of epoxy resin E44, 35 parts of curing agent phthalic anhydride, 0.75 parts of antioxidant DLTDP, 0.6 parts of ultraviolet absorber UV-327, and 4 parts of silane coupling agent KH-560 are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber core, with the coating amount controlled at 60 g / m². 2The flame-retardant and weather-resistant polyester fiber was obtained by curing at 120℃ for 2.5 hours.

[0054] The only difference between this example and Example 1 is that the self-regulating functional layer finishing liquid in this example does not contain hollow expandable microspheres.

[0055] The only difference between this example and Example 1 is that the self-regulating functional layer finishing liquid in this example does not contain modified nano-mica sheets.

[0056] The only difference between this example and Example 1 is that the self-regulating functional layer finishing solution in this example does not contain modified flake magnesium hydroxide, and the fiber core in this example is prepared through the following steps: S1-1. Preparation of loaded microspheres, the specific steps are the same as in Example 1; S1-2. 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours are mixed with 8 parts by weight of loaded microspheres and 15 parts by weight of modified flake magnesium hydroxide. The mixture is stirred for 45 minutes. The resulting mixture is added to a twin-screw extruder and melt-extruded at 245°C. The resulting melt is spun to obtain a fiber core. The spinning temperature is 260°C, the spinning speed is 600 m / min, the draw ratio is 2, and the stretching rate is 550 m / min.

[0057] A flame-retardant and weather-resistant polyester fiber comprises, from the inside out, a fiber core, a self-regulating functional layer, and an outer protective layer. Its preparation process includes the following steps: S1. Preparation of fiber core: 100 parts by weight of polyester chips that have been vacuum dried at 120°C for 10 hours are mixed with 6.65 parts by weight of mesoporous silica and stirred for 45 minutes. The resulting mixture is then added to a twin-screw extruder and melt-extruded at 245°C. The resulting melt is then spun to obtain a fiber core. The spinning temperature is 260°C, the spinning speed is 600 m / min, the draw ratio is 2, and the stretching rate is 550 m / min.

[0058] S2. A self-regulating functional layer is coated on the fiber core to obtain a fiber intermediate. The specific steps are the same as in Example 1. S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 70 parts of epoxy resin E44, 35 parts of curing agent phthalic anhydride, 1.5 parts of antioxidant DLTDP, 1.2 parts of ultraviolet absorber UV-327, and 4 parts of silane coupling agent KH-560 are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 60 g / m². 2 The flame-retardant and weather-resistant polyester fiber was obtained by curing at 120℃ for 2.5 hours.

[0059] 1. The average particle size of the hollow expandable microspheres prepared in Example 1 was measured at different temperatures (dynamic light scattering test was performed using a HORIBA LA-350 laser scattering particle size distribution analyzer to obtain the average particle size of the hollow expandable microspheres). The test results are as follows: Figure 1 As shown, the particle size of hollow expandable microspheres gradually increases with increasing temperature.

[0060] 2. Reference Figure 2 The image shows the XRD pattern of the self-regulating functional layer in Example 1, illustrating the successful coating of modified nano-mica sheets and modified sheet-like magnesium hydroxide on the fiber core.

[0061] 3. Release performance of additives (taking antioxidants as an example) at different temperatures Take 20g of fiber intermediate, cut it into 2mm long samples, and add it to 500mL of toluene. Seal the container and stir at 300rpm. Test the concentration of antioxidant DLTDP in the solution after different soaking times at 25℃ and 60℃ (detection by gas chromatography), and calculate the release amount of antioxidant DLTDP. Continue testing for 216h, and plot the release curve with the cumulative release percentage on the ordinate and soaking time on the abscissa. Wherein, the cumulative release percentage K = Q t Q0 represents the cumulative release amount within time t, and Q0 represents the total loading of antioxidant DLTDP. Q0 can be obtained by subtracting the mass of the remaining antioxidant DLTDP after impregnation from the total mass of antioxidant DLTDP in the adjuvant impregnation solution in step S1-1 of Example 1.

[0062] The antioxidant release curves of the fiber intermediates prepared in Example 1, Example 2 and Comparative Example 2 were tested respectively. In addition, a verification example was set up (to verify the recoverable characteristics of the opening and closing of the auxiliary agent release channel). The verification example used the fiber intermediate prepared in Example 1, which was vacuum kept at 60°C for 1 hour, then cooled to 25°C, and its antioxidant release curve was tested in the same way as above.

[0063] Test results are as follows Figure 3As shown, the fiber intermediates of Examples 1, 2, and Comparative Example 2 can all achieve a sustained-release effect of antioxidants, and the release rate of antioxidants increases with increasing temperature. However, the increase in release rate of Examples 1 and 2 with increasing temperature is significantly higher than that of Comparative Example 2. This is because the self-regulating functional layer of Comparative Example 2 does not contain hollow expandable microspheres, and the increase in release rate with increasing temperature is mainly due to increased molecular motion. In contrast, Examples 1 and 2 include hollow expandable microspheres, which expand upon heating, widening the gaps between the scales in the self-regulating functional layer, thereby increasing the release rate of antioxidants. Furthermore, compared to Example 1, Example 2 shows a greater increase in release rate with increasing temperature, attributed to the higher content of hollow expandable microspheres in Example 2. Comparing the release curve of the verification example with the release curve of Example 1 at 25°C, and combining the results of Example 1 at 25°C and 60°C, it can be shown that the gaps between the scales in the self-regulating functional layer (i.e., the release channels of the additives) widen with increasing temperature, which macroscopically manifests as... Figure 3 The release rate at 60°C / Example 1 was higher than that at 25°C / Example 1; however, as the temperature decreased, the gap narrowed, returning to a state close to the initial state, which macroscopically manifested as... Figure 3 The release curve of the experimental case is similar to that of Example 1 at 25°C.

[0064] 4. Fracture strength The tensile strength of polyester fibers was measured according to the standard GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments". The test results are shown in Table 1 below: Table 1

[0065] The test results show that Examples 1-3 have high tensile strength, while Comparative Examples 1, 3, and 4 show varying degrees of decrease. The results of Comparative Example 1 indicate that the self-regulating functional layer has an enhancing effect on the strength of polyester fibers. The results of Comparative Examples 3 and 4 indicate that the modified nano-mica sheets and modified flake magnesium hydroxide in the self-regulating functional layer can both enhance the strength of polyester fibers.

[0066] 5. Resistance to heat and oxygen aging Polyester fiber samples were placed in a hot air drying oven and subjected to thermo-oxidative aging tests at 140℃ in air atmosphere for 240 hours. The tensile strength after aging was measured, and the tensile strength retention rate was calculated as follows: tensile strength retention rate = (tensile strength after thermo-oxidative aging / tensile strength before thermo-oxidative aging) × 100%. The test results are shown in Table 2 below. Table 2

[0067] The test results show that Examples 1-3 have excellent heat and oxygen aging resistance. In Comparative Example 1, the heat and oxygen aging resistance is significantly reduced due to the lack of a self-regulating functional layer. In Comparative Example 2, the lack of the self-regulating release effect provided by the hollow expandable microspheres leads to a decrease in heat and oxygen aging resistance. The results of Comparative Example 3 indicate that the modified nano-mica sheets can improve the heat and oxygen aging resistance of polyester fibers. In Comparative Example 5, the antioxidant was not loaded through mesoporous silica, resulting in a significant reduction in the utilization efficiency and duration of the antioxidant, ultimately leading to a significant decrease in its heat and oxygen aging resistance.

[0068] 6. Flame retardant properties The limiting oxygen index (LOI) was tested according to standard GB / T 2406.2-2009, and the test results are shown in Table 3 below: Table 3

[0069] The test results show that Examples 1-3 exhibit excellent flame retardant properties. Comparative Example 1 lacks a self-regulating functional layer. Although modified flake magnesium hydroxide was added to the raw materials, its dispersibility was inferior to that of Example 1, leading to a decrease in the limiting oxygen index. The reason for the decrease in the limiting oxygen index in Comparative Example 4 is similar. The results of Comparative Example 3 indicate that modified nano-mica flakes have an improving effect on flame retardant properties.

[0070] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A flame-retardant and weather-resistant polyester fiber, characterized in that, From the inside out, it consists of a fiber core, a self-adjusting functional layer, and an outer protective layer: The fiber core is obtained by melt spinning a mixture of loaded microspheres and polyester chips, wherein the loaded microspheres are mesoporous silica loaded with antioxidants. The self-regulating functional layer is obtained by impregnating the fiber core in a self-regulating functional layer finishing solution. The preparation method of the self-regulating functional layer finishing solution is as follows: hollow expandable microspheres, modified nano mica sheets, and modified flake magnesium hydroxide are added and dispersed in deionized water, dopamine is added, and the pH is adjusted to alkaline to obtain the self-regulating functional layer finishing solution. The outer protective layer is obtained by coating the self-regulating functional layer with an outer protective layer coating and then curing it. The raw materials of the outer protective layer coating include, by weight, 50-90 parts of epoxy resin, 25-45 parts of curing agent, 0.5-1.5 parts of antioxidant, 0.3-1.2 parts of ultraviolet absorber, and 2-8 parts of silane coupling agent.

2. The flame-retardant and weather-resistant polyester fiber according to claim 1, characterized in that, The mass ratio of loaded microspheres to polyester chips is 4-16:100; The preparation method of loaded microspheres is as follows: mesoporous silica is added to an additive impregnation solution containing antioxidants and ultraviolet absorbers, stirred under heating, then shaken on a shaker at room temperature, filtered, washed, and vacuum dried to obtain mesoporous silica loaded with additives, i.e., loaded microspheres.

3. The flame-retardant and weather-resistant polyester fiber according to claim 1, characterized in that, Hollow expandable microspheres were prepared by the following method: styrene, divinylbenzene, acrylonitrile, methyl methacrylate, and butyl acrylate were mixed to obtain a monomer mixture; SiO2 microspheres, CTAB, and ammonium persulfate were added to deionized water and ultrasonically dispersed under nitrogen purging; the monomer mixture was added dropwise to the resulting dispersion under stirring; the reaction was carried out under nitrogen protection and heated; after the reaction was completed, the mixture was centrifuged, washed, and the solid product was added to an HF aqueous solution, stirred, filtered, washed, and dried to obtain hollow expandable microspheres.

4. The flame-retardant and weather-resistant polyester fiber according to claim 3, characterized in that, The particle size of SiO2 microspheres is 200-800 nm.

5. The flame-retardant and weather-resistant polyester fiber according to claim 1, characterized in that, The preparation method of the self-regulating functional layer finishing solution is as follows: hollow expandable microspheres, modified nano mica sheets, and modified flake magnesium hydroxide are added and dispersed in deionized water, dopamine is added, and the pH is adjusted to alkaline to obtain the self-regulating functional layer finishing solution.

6. The flame-retardant and weather-resistant polyester fiber according to claim 1, characterized in that, The antioxidant is selected from at least one of the following: antioxidant DLTDP, antioxidant DLTP, antioxidant DSTP, antioxidant 1010, and antioxidant 168; The ultraviolet absorber is selected from at least one of UV-327, UV-P, UV531, and UV326; The epoxy resin is epoxy resin E44, the curing agent is phthalic anhydride, and the silane coupling agent is KH-560.

7. A process for preparing flame-retardant and weather-resistant polyester fiber as described in any one of claims 1-6, characterized in that, Includes the following steps: S1-1, Preparation of loaded microspheres: Mesoporous silica was added to an additive impregnation solution containing antioxidants and ultraviolet absorbers, stirred under heating, then shaken on a shaker at room temperature, filtered, washed, and vacuum dried to obtain loaded microspheres. S1-2. Polyester chips are mixed with loaded microspheres, then melt-extruded, and the resulting melt is spun to obtain a fiber core. S2. A self-regulating functional layer is coated onto the fiber core to obtain the fiber intermediate: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add flake magnesium hydroxide or nano mica flakes to deionized water, disperse by ultrasonication, add stearic acid aqueous solution dropwise under stirring, heat and stir, filter, wash, and dry to obtain modified flake magnesium hydroxide or nano mica flakes. S2-2, Preparation of hollow expandable microspheres: S2-2-1. Styrene, divinylbenzene, acrylonitrile, methyl methacrylate, and butyl acrylate are mixed to obtain a monomer mixture; S2-2-2, SiO2 microspheres, CTAB, and ammonium persulfate were added to deionized water and ultrasonically dispersed under nitrogen. The monomer mixture was added dropwise to the resulting dispersion under stirring and heated under nitrogen protection. After the reaction was completed, the mixture was centrifuged, washed, and the solid product was added to an HF aqueous solution. The mixture was stirred, filtered, washed, and dried to obtain hollow expandable microspheres. S2-3. Hollow expandable microspheres, modified nano mica sheets, and modified flake magnesium hydroxide are added and dispersed in deionized water. Dopamine is added and the pH is adjusted to alkaline to obtain a self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, remove it and vacuum dry it to obtain the fiber intermediate. S3. Cover the self-adjusting functional layer with an outer protective layer: By weight, 50-90 parts of epoxy resin, 25-45 parts of curing agent, 0.5-1.5 parts of antioxidant, 0.3-1.2 parts of UV absorber, and 2-8 parts of silane coupling agent are mixed and stirred evenly to obtain an outer protective coating. The outer protective coating is applied to the surface of the fiber intermediate and cured by heating to obtain the flame-retardant and weather-resistant polyester fiber.

8. The preparation process of flame-retardant and weather-resistant polyester fiber according to claim 7, characterized in that, Step S1 is as follows: S1-1, Preparation of loaded microspheres: Add 1-4g of mesoporous silica to 25-100mL of additive impregnation solution, stir at 40-60℃ for 2-8h, then shake on a shaker at room temperature for 6-24h, filter, wash, and dry to obtain loaded microspheres; wherein, the additive impregnation solution is a toluene solution containing 6-10mg / mL of antioxidant DLTDP and 2-8mg / mL of ultraviolet absorber UV-327; S1-2. Mix 100 parts by weight of pre-dried polyester chips with 4-16 parts by weight of loaded microspheres, and then melt-extrude at 235-260℃. The resulting melt is spun to obtain a fiber core.

9. The preparation process of flame-retardant and weather-resistant polyester fiber according to claim 7, characterized in that, Step S2 is as follows: S2-1. Preparation of modified flake magnesium hydroxide and modified nano-mica flakes: Add 2.5-10g of flake magnesium hydroxide or nano mica flakes to 75-300mL of deionized water, ultrasonically disperse for 0.5-2h, add 5-20mL of stearic acid aqueous solution with a concentration of 1-5mg / mL dropwise while stirring, stir at 70-90℃ for 45-180min, filter, wash, and dry to obtain modified flake magnesium hydroxide or nano mica flakes; S2-2, Preparation of hollow expandable microspheres: S2-2-1. Mix 2.1-8.4g styrene, 0.5-2g divinylbenzene, 1.25-5g acrylonitrile, 0.6-2.5g methyl methacrylate, and 1-4g butyl acrylate to obtain a monomer mixture. S2-2-2: Add 0.25-1g of SiO2 microspheres with a particle size of 200-800nm, 0.6-2.5g of CTAB, and 0.15-0.6g of ammonium persulfate to 60-250mL of deionized water, and ultrasonically disperse under nitrogen for 30-90min. Add the monomer mixture dropwise to the resulting dispersion while stirring. Under nitrogen protection, react at 60-70℃ for 6-12h. Centrifuge, wash the solid product with deionized water, and then add it to 50-200mL of HF aqueous solution with a concentration of 15-40wt%. Stir at 30-50℃ for 3-8h, filter, wash, and dry to obtain hollow expandable microspheres. S2-3. Take 0.125-0.5g of hollow expandable microspheres, 0.25-1g of modified nano-mica sheets, and 0.3-1.6g of modified flake magnesium hydroxide and add them to 75-300mL of deionized water. Disperse the mixture by ultrasonication for 0.5-2h. Then add 0.75-3g of dopamine and stir for 30-90min. Adjust the pH value to 8-10 with 0.05-0.2mol / L NaOH solution and stir for 15-60min to obtain the self-regulating functional layer finishing solution. S2-4. Immerse the fiber core in the self-regulating functional layer finishing solution, controlling the mass ratio of fiber core to self-regulating functional layer finishing solution to 1:8-15. Immerse at 30-50℃ for 10-40 minutes, then remove and vacuum dry at 50-75℃ for 6-10 hours to complete one immersion treatment. Repeat the immersion 2-5 times to obtain the fiber intermediate.

10. The preparation process of flame-retardant and weather-resistant polyester fiber according to claim 7, characterized in that, Step S3 is as follows: By weight, 50-90 parts epoxy resin, 25-45 parts curing agent, 0.5-1.5 parts antioxidant, 0.3-1.2 parts UV absorber, and 2-8 parts silane coupling agent are mixed and stirred evenly to obtain the outer protective coating. The outer protective coating is then applied to the surface of the fiber intermediate, with the coating amount controlled at 40-80 g / m². 2 The flame-retardant and weather-resistant polyester fiber is obtained by curing at 100-140℃ for 1.5-5 hours.

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