Ultra-dull polyester fiber and preparation method thereof

Abstract

The invention discloses an ultra-dull polyester fiber and a preparation method thereof, the ultra-dull polyester fiber is obtained by spinning ultra-dull polyester chips, and the ultra-dull polyester chips are obtained by polymerizing terephthalic acid, ethylene glycol, a composite modified delustering agent and a catalyst as raw materials. The super-dull polyester fiber prepared by the invention is excellent in dull performance, good in mechanical strength and excellent in light aging resistance. In the composite modified delustering agent, the nano titanium dioxide with the porous structure can improve the delustering performance and facilitate the promotion of carbon dot deposition coating, and the negative influence of the photocatalytic activity of titanium dioxide on a polyester system can be reduced through the effects of physical isolation, diffuse reflection increase, reducibility endowing and the like of reduced carbon dot coating; and the polymer film coated on the outermost side can solve the problem of compatibility and realize uniform dispersion of the carbon dot coated modified titanium dioxide particles in a polyester system.

Description

Technical Field

[0001] The present invention relates to the field of polyester fibers, and particularly to a super-dull polyester fiber and a preparation method thereof. Background Art

[0002] Polyester (PET) fiber is one of the polymer products with the largest production volume, the widest application, and the fastest development speed globally.

[0003] Dull polyester fiber, also known as matte fiber, refers to a chemical fiber with no luster on the surface. The method for preparing dull fiber is usually to add a dulling agent to the spinning solution or melt before spinning, and through spinning and forming, the obtained dull fiber can scatter light to eliminate luster, reduce transparency, and increase whiteness. In recent years, fully dull polyester fiber has been increasingly accepted by the weaving industry due to its unique external appearance characteristics.

[0004] Titanium dioxide has outstanding coloring power, covering power, and dulling ability, and is a commonly used dulling agent in polyester fibers. However, its main disadvantages include: (1) Titanium dioxide particles are small, have poor compatibility with polymers, and are difficult to be uniformly dispersed in polyester, which will affect the performance of dulling and is also likely to have an adverse impact on the mechanical properties and spinnability of polyester fibers; (2) Titanium dioxide has excellent photocatalytic activity, and under light irradiation, free radicals and reactive oxygen species with strong oxidation ability will be generated. These substances can decompose organic substances, accelerate the degradation and aging of polyester, and will deteriorate the aging resistance of polyester fibers. The above-mentioned disadvantages limit the application of titanium dioxide as a dulling agent in polyester fibers.

[0005] Patent CN111286805B discloses a method and product for directly spinning a melt to prepare a titanium-based dull polyester fiber, in which a polyester prepolymer is coated on the outside of TiO2 nanoparticles, improving the structural stability of TiO2 nanoparticles.

[0006] Patent CN114621423B discloses a preparation method of a titanium-based dull polyester fiber with good spinnability. It performs surface coating on titanium dioxide, improves the dispersibility of titanium dioxide by distributive polymerization and adding cellulose to construct a network structure, and can reduce the adverse reactions caused by its photocatalysis to a certain extent.

[0007] Patent CN108277550B discloses a dull PET fiber and a method for preparing it by chip spinning. Through polymer coating treatment, while solving the problem of the dispersibility of titanium dioxide, the dulling effect of titanium dioxide is improved, and the addition amount of titanium dioxide in the fiber is reduced.

[0008] Through polymer coating of titanium dioxide, the above-mentioned patent can, to a certain extent, solve the dispersion problem of titanium dioxide and weaken the influence of its photocatalytic activity on the polyester system. However, this weakening effect is mainly based on the physical isolation effect formed by the polymer film coating, which depends on the density and stability of the polymer film. When the polymer film coating is not dense enough or breaks or melts under the high temperature during the subsequent preparation process, the effect of this physical isolation will be greatly reduced or even lost. At this time, it will be difficult to reliably inhibit the damage to the polyester system caused by the photocatalytic activity of titanium dioxide.

[0009] Therefore, it is necessary to improve the existing technology to provide a more reliable solution. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a super-dull polyester fiber and its preparation method in view of the deficiencies in the above-mentioned prior art.

[0011] To solve the above technical problem, the technical solution adopted by the present invention is: a super-dull polyester fiber obtained by spinning super-dull polyester chips, and the super-dull polyester chips are polymerized from terephthalic acid, ethylene glycol, a composite modified dulling agent, and a catalyst as raw materials;

[0012] The preparation method of the composite modified dulling agent includes the following steps:

[0013] S1. Prepare aluminum-doped porous nano-titanium dioxide;

[0014] S2. In-situ coat reduced carbon dots on the surface of aluminum-doped porous nano-titanium dioxide by hydrothermal method to obtain carbon dot-coated modified titanium dioxide particles;

[0015] S3. Coat a polymer film on the surface of the carbon dot-coated modified titanium dioxide particles to obtain a composite modified dulling agent;

[0016] The polymer film is a polymethyl methacrylate polymer film doped and modified with polyurethane acrylate and N-phenyl maleimide.

[0017] Preferably, step S1 is specifically as follows:

[0018] S1-1. Add tetrabutyl titanate to ethanol, and drop the obtained mixture into deionized water and stir;

[0019] S1-2. Add aluminum nitrate and ethanol to the product of step S1-1, then add ammonium bicarbonate and stir. Add the obtained product to a reaction kettle, react under heating, wash, dry, and calcine the product to obtain aluminum-doped porous nano-titanium dioxide.

[0020] Preferably, step S2 is specifically as follows:

[0021] S2-1. Take aluminum-doped porous nano-titanium dioxide and benzenesulfonic acid and add them to deionized water, and ultrasonically disperse to obtain dispersion liquid 1;

[0022] S2-2. Take vitamin C, L-cysteine, and ethanol and add them to deionized water, stir, and then add chitosan, and stir to obtain dispersion liquid 2;

[0023] S2-3. Add dispersion liquid 2 to dispersion liquid 1, ultrasonically disperse to obtain a carbon dot precursor solution, transfer the carbon dot precursor solution to a reaction kettle, react under heating, centrifuge and filter, wash the solid product, and vacuum dry to obtain carbon dot-coated modified titanium dioxide particles.

[0024] Preferably, step S3 is specifically as follows:

[0025] S3-1. Take carbon dot-coated modified titanium dioxide particles and an emulsifier and add them to deionized water, and ultrasonically disperse to obtain a nano-particle dispersion liquid;

[0026] S3-2. Take methyl methacrylate, polyurethane acrylate, N-phenyl maleimide, n-pentanol, an emulsifier, and deionized water, mix them, and ultrasonically disperse; add the obtained mixture to the nano-particle dispersion liquid under stirring, add potassium persulfate, heat and react, demulsify after the reaction ends, filter by suction, wash and dry the solid product to obtain a composite modified matting agent;

[0027] The emulsifier is sodium dodecylbenzenesulfonate.

[0028] Preferably, step S1 is specifically as follows:

[0029] S1-1. Take 5-20 mL of tetrabutyl titanate and add it to 25-100 mL of ethanol, ultrasonically disperse for 5-30 min, and add the obtained mixture dropwise to 150-600 mL of deionized water under stirring, and stir for 30-90 min;

[0030] S1-2. Add 1.065-4.26 g of aluminum nitrate and 25-100 mL of ethanol to the product of step S1-1, then add 3.25-13 g of ammonium bicarbonate, stir for 15-60 min, add the obtained product to a reaction kettle, react at 200-240 °C for 4-16 h, cool to room temperature, wash the product by centrifugation with ethanol, dry at 50-70 °C for 6-24 h, then calcine at 420-550 °C for 1-4 h, cool to room temperature and grind to obtain aluminum-doped porous nano-titanium dioxide.

[0031] Preferably, step S2 is specifically as follows:

[0032] S2-1: Take 0.25 - 1 g of aluminum-doped porous nano-titanium dioxide and 0.316 - 1.264 g of benzenesulfonic acid, add them to 50 - 200 mL of deionized water, and ultrasonically disperse for 15 - 60 min to obtain dispersion liquid 1;

[0033] S2-2: Take 0.264 - 1.056 g of vitamin C, 0.242 - 0.968 g of L-cysteine, 10 - 40 mL of ethanol, add them to 40 - 160 mL of deionized water, stir for 5 - 15 min, then add 0.483 - 1.932 g of chitosan with a deacetylation degree greater than 70%, and stir for 5 - 30 min to obtain dispersion liquid 2;

[0034] S2-3: Under stirring, add dispersion liquid 2 to dispersion liquid 1, ultrasonically disperse for 15 - 60 min to obtain a carbon dot precursor solution. Transfer the carbon dot precursor solution to a reaction kettle with a polytetrafluoroethylene inner lining, react at 150 - 190 °C for 7 - 24 h, cool to room temperature, then centrifuge and filter. Wash the solid product with ethanol and vacuum dry at 60 - 75 °C for 6 - 24 h to obtain carbon dot-coated modified titanium dioxide particles.

[0035] Preferably, step S3 is specifically as follows:

[0036] S3-1: Take 1.25 - 5 g of carbon dot-coated modified titanium dioxide particles and 0.5 - 2 g of sodium dodecylbenzenesulfonate, add them to 25 - 100 mL of deionized water, and ultrasonically disperse for 15 - 60 min to obtain a nano-particle dispersion liquid;

[0037] S3-2: Take 3.25 - 13 g of methyl methacrylate, 0.75 - 3 g of polyurethane acrylate, 0.75 - 3 g of N-phenylmaleimide, 1 - 4 g of n-pentanol, 1.5 - 6 g of sodium dodecylbenzenesulfonate, and 50 - 200 g of deionized water, mix them and ultrasonically disperse for 5 - 20 min; add the obtained mixture to the nano-particle dispersion liquid under stirring, keep stirring, introduce nitrogen into the obtained mixed system for 15 - 60 min, then add 5 - 20 mL of potassium persulfate aqueous solution containing 0.125 - 0.5 g of potassium persulfate, react at 60 - 65 °C for 1 - 4 h, then dropwise add 5 - 20 mL of potassium persulfate aqueous solution containing 0.125 - 0.5 g of potassium persulfate, raise the temperature to 70 - 75 °C, react for 0.5 - 2 h, then raise the temperature to 78 - 82 °C, react for 0.5 - 2 h, stop heating, demulsify with 3 wt% aluminum sulfate solution, filter by suction, wash the solid product with ethanol, and vacuum dry at 50 - 80 °C for 12 - 48 h to obtain a composite modified matting agent;

[0038] Among them, the polyurethane acrylate is prepared by the following method:

[0039] S3-2-1. Add polyethylene glycol to butyl acetate, and successively dropwise add 2,4-toluene diisocyanate and dibutyltin dilaurate under stirring. React at 60 - 70 °C for 1 - 4 h. After cooling to room temperature, add hydroxyethyl acrylate and hydroxyoctyl methacrylate, and continue to react at 70 - 78 °C for 0.5 - 2 h. Cool to room temperature to obtain a crude polyurethane acrylate product;

[0040] S3-2-2. Purify the crude polyurethane acrylate product to obtain polyurethane acrylate.

[0041] Preferably, the preparation method of the composite modified matting agent comprises the following steps:

[0042] S1. Prepare aluminum-doped porous nano-titanium dioxide:

[0043] S1-1. Take 10 mL of tetrabutyl titanate and add it to 50 mL of ethanol. Ultrasonically disperse for 10 min. Drop the obtained mixture into 300 mL of deionized water under stirring and stir for 45 min;

[0044] S1-2. Add 2.13 g of aluminum nitrate and 50 mL of ethanol to the product of step S1-1, then add 6.5 g of ammonium bicarbonate, stir for 30 min. Add the obtained product to a reaction kettle, react at 220 °C for 8 h. After cooling to room temperature, wash the product by centrifugation with ethanol, dry at 60 °C for 12 h, then calcine at 450 °C for 2 h. After cooling to room temperature, grind to obtain aluminum-doped porous nano-titanium dioxide;

[0045] S2. Prepare carbon dot-coated modified titanium dioxide particles:

[0046] S2-1. Take 0.5 g of aluminum-doped porous nano-titanium dioxide and 0.632 g of benzenesulfonic acid and add them to 100 mL of deionized water. Ultrasonically disperse for 30 min to obtain dispersion liquid 1;

[0047] S2-2. Take 0.528 g of vitamin C, 0.484 g of L-cysteine, 20 mL of ethanol and add them to 80 mL of deionized water. Stir for 5 min, then add 0.966 g of chitosan with a deacetylation degree greater than 70%, and stir for 15 min to obtain dispersion liquid 2;

[0048] S2-3. Add dispersion liquid 2 to dispersion liquid 1 under stirring, ultrasonically disperse for 30 min to obtain a carbon dot precursor solution. Transfer the carbon dot precursor solution to a reaction kettle with a polytetrafluoroethylene inner lining, react at 170 °C for 14 h. After cooling to room temperature, centrifuge and filter. Wash the solid product with ethanol and vacuum dry at 70 °C for 12 h to obtain carbon dot-coated modified titanium dioxide particles;

[0049] S3. Coating a polymer film:

[0050] S3-1. Take 2.5 g of carbon dot-coated modified titanium dioxide particles and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nanoparticle dispersion;

[0051] S3-2. Take 6.5 g of methyl methacrylate, 1.5 g of polyurethane acrylate, 1.5 g of N-phenylmaleimide, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them, and ultrasonically disperse for 10 min; add the obtained mixture to the nanoparticle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution with the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain a composite modified matting agent;

[0052] Among them, the polyurethane acrylate is prepared by the following method:

[0053] S3-2-1. Take polyethylene glycol and add it to butyl acetate, sequentially dropwise add 2,4-toluene diisocyanate and dibutyltin dilaurate under stirring, react at 68 °C for 2 h, after cooling to room temperature, add 2-hydroxyethyl acrylate and 2-hydroxyoctyl methacrylate, continue to react at 72 °C for 1 h, and cool to room temperature to obtain a crude polyurethane acrylate product;

[0054] Among them, the molar ratio of 2,4-toluene diisocyanate: polyethylene glycol: 2-hydroxyethyl acrylate: 2-hydroxyoctyl methacrylate is 2:1:1.2:1, the mass of dibutyltin dilaurate is 0.5% of the mass of polyethylene glycol, and the mass of butyl acetate is 20% of the sum of the masses of 2,4-toluene diisocyanate, polyethylene glycol, 2-hydroxyethyl acrylate, and 2-hydroxyoctyl methacrylate;

[0055] S3-2-2. Precipitate the crude polyurethane acrylate product with petroleum ether, separate the precipitate and dissolve it with butyl acetate, then place the obtained mixture in petroleum ether for precipitation, and finally separate the precipitate to obtain the purified polyurethane acrylate.

[0056] The main synthesis mechanism of the multi-component composite modified material provided by the present invention is as follows:

[0057] The present invention first uses tetrabutyl titanate as the titanium source, aluminum nitrate as the aluminum source, and ammonium bicarbonate as the structure guiding agent, and prepares aluminum (aluminum trioxide)-doped porous nano-titanium dioxide through a hydrothermal method combined with a high-temperature calcination process;

[0058] Then, using benzenesulfonic acid, vitamin C, and L-cysteine as the carbon dot raw materials, water and ethanol as solvents, a reducing carbon dot is in-situ deposited on the surface of aluminum-doped porous nano-titanium dioxide by a one-pot hydrothermal method to form a composite particle with aluminum-doped porous nano-titanium dioxide as the core and a carbon dot coating layer as the shell: carbon dot-coated modified titanium dioxide particles;

[0059] In this process, benzenesulfonic acid, as the carbon source and also as an organic acid, is first mixed with aluminum-doped porous nano-titanium dioxide, enabling a certain number of Al 3+ and Ti 4 + to be generated on the surface of aluminum-doped porous nano-titanium dioxide under the action of acidity. 3+ Then, by virtue of the binding (such as electrostatic adsorption and complex coordination) of Al 4+ , Ti

[0060] Finally, through an in-situ polymerization process, a polymethyl methacrylate grafted with polyurethane acrylate and N-phenyl maleimide is coated on the surface of the carbon dot-coated modified titanium dioxide particles to obtain a composite modified matting agent with aluminum-doped porous nano-titanium dioxide as the core, a reduced carbon dot coating layer as the middle coating layer, and a polymethyl methacrylate grafted with polyurethane acrylate and N-phenyl maleimide as the outer coating layer.

[0061] Titanium dioxide has outstanding matting ability and is a commonly used matting agent in polyester fibers. However, its main drawbacks include: (1) Titanium dioxide particles are small, with poor compatibility with polymers, making it difficult to disperse evenly in polyester, which will affect the performance of matting and is also likely to have an adverse impact on the mechanical properties and spinnability of polyester fibers; (2) Titanium dioxide has excellent photocatalytic activity, and under light, free radicals and reactive oxygen species with strong oxidation ability will be generated. These substances can decompose organic matter and accelerate the degradation and aging of polyester, deteriorating the aging resistance of polyester fibers. The above-mentioned drawbacks limit the application of titanium dioxide as a matting agent in polyester fibers.

[0062] In the present invention, a composite modified matting agent with an aluminum-doped porous nano-titanium dioxide core, a reduced carbon dot coating layer as the intermediate coating layer, and a poly(methyl methacrylate) copolymerized with polyurethane acrylate and N-phenyl maleimide as the outer coating layer can overcome the above-mentioned defects of using titanium dioxide as a matting agent: the nano-titanium dioxide with a porous structure can improve the matting performance and facilitate the deposition and coating of carbon dots. The coating of reduced carbon dots can reduce the adverse effects of the photocatalytic activity of titanium dioxide on the polyester system through physical isolation, increasing diffuse reflection, and imparting reducibility. The outermost polymer film can solve the compatibility problem and achieve the uniform dispersion of carbon dot-coated modified titanium dioxide particles in the polyester system. The following further analyzes the action mechanisms of the various structural components in the composite modified matting agent to facilitate the understanding of the present invention.

[0063] 1. The nano-titanium dioxide with a porous structure can increase the surface roughness, enhance light scattering and diffuse reflection. Moreover, due to the large number of pores inside the porous structure, a complex light propagation path will be formed, causing the incident light to undergo multiple scatterings at the pore interfaces instead of being reflected in a single direction, thereby reducing the specular reflectance. The concave structure on the surface of the porous nano-titanium dioxide can form a "light trap", effectively extending the light propagation path and increasing the scattering probability. On the other hand, the pores on the surface of the nano-titanium dioxide can produce an adsorption effect on the solid, improving the interfacial bonding force, which is conducive to the in-situ deposition and coating of carbon dots and can also have a favorable impact on the subsequent coating of the polymer film to a certain extent.

[0064] The rich pore structure is likely to make the nano-titanium dioxide brittle. The doping of aluminum oxide can increase the strength of the porous nano-titanium dioxide, offset the brittleness brought by the pore structure, and at the same time improve the thermal stability of the porous nano-titanium dioxide, reducing the collapse of the pore structure. The doping of aluminum can also provide favorable attachment conditions for the subsequent carbon dot deposition.

[0065] 2. The carbon dots prepared in the present invention inherit the reducibility of vitamin C and benzenesulfonic acid well and exhibit strong antioxidant ability. The carbon dots form a "strawberry-like" outer shell structure on the surface of the aluminum-doped porous nano-titanium dioxide. On the one hand, this outer shell can form a physical shield, which can limit the oxidative substances such as free radicals (such as hydroxyl radicals) and reactive oxygen species generated by the photocatalysis of titanium dioxide inside the outer shell to a certain extent, avoiding their contact with the polyester system, thereby reducing the impact of these oxidative substances on the polymer system. On the other hand, the carbon dots have strong reducibility and can capture the generated free radicals, reactive oxygen species, etc., thus offsetting the photocatalytic activity of titanium dioxide. Therefore, the coating of carbon dots can form an effect combining physical and chemical effects, shielding the influence of the photocatalytic activity of titanium dioxide on the polyester system. At the same time, the coating shell formed by the close arrangement of spherical carbon dots can greatly increase the surface roughness, enhance light diffuse reflection, and is conducive to further improving the matting effect.

[0066] 3. Polymethyl methacrylate is a transparent polymer material with good moldability and mechanical strength, and has been used for coating inorganic particles (such as titanium dioxide) (Tan Dingsheng, Yan Nianxi. Study on the surface modification of TiO2 with polymethyl methacrylate [J]. Journal of Shanghai University: Natural Science Edition, 1996, 2(4): 425-430.). The coating of polymethyl methacrylate can greatly improve the compatibility between the carbon dot-coated modified titanium dioxide particles and the polyester system and promote their uniform dispersion. However, in the preparation of the composite modified delustering agent in the present invention and during the subsequent melt spinning process for preparing super delustering polyester chips, there will be high-temperature reaction conditions, and the heat resistance of polymethyl methacrylate is insufficient. In the present invention, by adding N-phenyl maleimide with excellent heat resistance during the in-situ polymerization process of polymethyl methacrylate, the heat resistance of polymethyl methacrylate can be improved. At the same time, by adding the self-made polyurethane acrylate, the crosslinking strength and interfacial bonding strength of the polymer film can be improved. The cooperation of these two aspects can improve the stability of the polymethyl methacrylate film layer at high temperatures and further improve the compatibility between polymethyl methacrylate and the polyester system.

[0067] The ring structure of unsaturated imide and the bulky side groups in the main chain of N-phenyl maleimide can effectively restrict the rotation of molecules, increase the rigidity of the molecular chain, and hinder the segmental movement, thereby significantly improving the heat resistance (Wu Weihong. Study on the heat resistance modification of polymethyl methacrylate with N-p-tolyl maleimide [D]. Hebei University, 2004. DOI: 10.7666 / d.d002043.).

[0068] The polyurethane acrylate prepared in the present invention has unsaturated double bonds at both ends, can undergo a free radical copolymerization reaction with methyl methacrylate monomers to form a crosslinked structure, and form an interpenetrating network crosslinked structure, which can provide film-forming strength and adhesion.

[0069] The coating of the polyurethane acrylate and N-phenyl maleimide co-grafted polymethyl methacrylate film on the outermost layer not only improves the heat resistance of the polymethyl methacrylate film, solves the compatibility problem between the carbon dot-coated modified titanium dioxide particles and the polyester system, but also, as the outermost organic barrier, can isolate the photocatalytic products of titanium dioxide and further reduce the adverse effects brought by the photocatalytic activity of titanium dioxide to the polyester system.

[0070] The present invention also provides a method for preparing the super delustering polyester fiber as described above, comprising the following steps:

[0071] Step 1: Take the composite modified matting agent and add it to ethylene glycol, then disperse it by ultrasonic wave to obtain a matting agent slurry; mix the matting agent slurry with terephthalic acid, ethylene glycol, and a catalyst, stir under heating, and raise the temperature for an esterification reaction;

[0072] Step 2: Add a catalyst, raise the temperature for a pre-polycondensation reaction;

[0073] Step 3: Raise the temperature for final polycondensation, discharge the material, cool it, and pelletize it to obtain super-matting polyester chips;

[0074] Step 4: Add the super-matting polyester chips to a melt spinning machine for melt spinning, winding, and stretching to obtain super-matting polyester fibers;

[0075] Among them, the catalyst is one or several of zinc acetate, magnesium acetate, calcium acetate, ethylene glycol, antimony acetate, and antimony trioxide.

[0076] Preferably, the preparation method of the super-matting polyester fiber includes the following steps:

[0077] Step 1: Take 24 - 96 g of the composite modified matting agent and add it to 50 - 200 g of ethylene glycol, disperse it by ultrasonic wave for 15 - 60 min to obtain a matting agent slurry; mix the obtained matting agent slurry with 0.5 - 2 kg of terephthalic acid, 0.25 - 1 kg of ethylene glycol, and 0.25 - 1 g of antimony glycolate, stir at 60 - 80 °C for 15 - 60 min, raise the temperature to 200 - 250 °C, and carry out an esterification reaction for 60 - 240 min, with the pressure controlled at 50 - 110 kPa;

[0078] Step 2: Add 0.0125 - 0.05 g of antimony acetate, raise the temperature to 255 - 270 °C, control the pressure at 5 - 15 kPa, and carry out a pre-polycondensation reaction for 30 - 90 min;

[0079] Step 3: Raise the temperature to 280 - 295 °C, control the pressure at 0.05 - 0.3 kPa, carry out final polycondensation for 30 - 100 min, discharge the material, cool it, and pelletize it to obtain super-matting polyester chips;

[0080] Step 4: Add the super-matting polyester chips to a melt spinning machine for melt spinning, winding, and stretching to obtain super-matting polyester fibers.

[0081] The beneficial effects of the present invention are:

[0082] The present invention provides a supermatting polyester fiber and a preparation method thereof. The supermatting polyester fiber prepared by the present invention has excellent matting performance, good mechanical strength, and excellent light aging resistance. In the present invention, a composite modified matting agent is constructed with aluminum-doped porous nano-titanium dioxide as the core, a reduced carbon dot coating layer as the middle coating layer, and a polymethyl methacrylate grafted with polyurethane acrylate and N-phenyl maleimide as the outer coating layer, which can overcome the defects of poor compatibility with polyester and easy damage to the polyester system by the photocatalytic activity of titanium dioxide when used as a matting agent.

[0083] In the composite modified matting agent of the present invention, the nano-titanium dioxide with a porous structure can improve the matting performance and facilitate the deposition and coating of carbon dots. The reduced carbon dot coating can reduce the adverse effects of the photocatalytic activity of titanium dioxide on the polyester system through physical isolation, increasing diffuse reflection, and imparting reducibility. The outermost polymer film can solve the compatibility problem and realize the uniform dispersion of the carbon dot-coated modified titanium dioxide particles in the polyester system.

[0084] In the composite modified matting agent of the present invention, the photocatalytic activity of titanium dioxide can be inhibited through the following aspects: (1) The physical isolation and shielding effect formed by the carbon dots as the middle coating layer restricts the photocatalytic active products of titanium dioxide; (2) The strong reducibility of the carbon dots captures free radicals, reactive oxygen species, etc., offsetting the photocatalytic activity of titanium dioxide; (3) The physical isolation and shielding effect formed by the outer polymer film restricts the photocatalytic active products of titanium dioxide. Therefore, the composite modified matting agent in the present invention can shield the influence of the photocatalytic activity of titanium dioxide on the polyester system through the combination of physical and chemical effects. This characteristic can greatly reduce the dependence on the density and stability of the coated polymer film. At the same time, since the polymethyl methacrylate grafted with polyurethane acrylate and N-phenyl maleimide is used as the outer coating layer in the present invention, the density and stability of the polymer film can be improved. Therefore, the above three effects are combined to greatly reduce the adverse effects of the photocatalytic activity of titanium dioxide on the polyester system. Description of the Drawings

[0085] Figure 1 XRD pattern of the aluminum-doped porous nano-titanium dioxide prepared in Example 1;

[0086] Figure 2 Infrared absorption spectrum of the carbon dot-coated modified titanium dioxide particles prepared in Example 1;

[0087] Figure 3 Antioxidant performance test results of the aluminum-doped porous nano-titanium dioxide (Al-TiO2) and carbon dot-coated modified titanium dioxide particles (Al-TiO2@CDs) prepared in Example 1;

[0088] Figure 4 Photocatalytic activity test results of the composite modified matting agent in Example 1, the nano-titanium dioxide in Comparative Example 1, and the composite modified matting agents in Comparative Examples 2-7;

[0089] Figure 5 Matting performance test results of the polyester fiber products prepared in the examples and comparative examples;

[0090] Figure 6 Breaking strength test results of the polyester fiber products prepared in the examples and comparative examples;

[0091] Figure 7 Anti-photoaging performance test results of the polyester fiber products prepared in the examples and comparative examples. Detailed implementation manners

[0092] The present invention will be further described in detail below in conjunction with examples, so that those skilled in the art can implement it according to the description in the specification.

[0093] It should be understood that terms such as "having", "comprising", and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0094] Unless otherwise specified, the test methods used in the following examples are all conventional methods. The materials and reagents used in the following examples can all be obtained from commercial sources unless otherwise specified. For those not indicating specific conditions in the following examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For those reagents or instruments not indicating the manufacturer, they are all conventional products that can be purchased commercially.

[0095] The sources of the main raw materials involved in the following examples and comparative examples are as follows:

[0096] Terephthalic acid and ethylene glycol are purchased from Nantong Changchen Chemical Co., Ltd.;

[0097] Antimony glycolate is from Jiangsu Bost Chemical Technology Co., Ltd.;

[0098] Antimony acetate is from Nanxing Chemical Industry (Jiangsu) Co., Ltd.;

[0099] Nano-titanium dioxide with an average particle size of 5 nm and anatase type is from Nanjing Baokete New Materials Co., Ltd.;

[0100] Polyethylene glycol, specifically polyethylene glycol 1000, is from Jiangsu Haian Petrochemical Factory;

[0101] Chitosan with a deacetylation degree of 90% is from Shanghai Yuanye Biotechnology Co., Ltd., product number S11064;

[0102] L-Cysteine, Jiangsu Caiwei Biotechnology Co., Ltd.;

[0103] Benzenesulfonic acid, Nanjing Pasteur Chemical Co., Ltd.;

[0104] 2,4-Toluene diisocyanate, butyl acetate, 2-Hydroxyethyl acrylate, 2-Hydroxyoctyl methacrylate, Dibutyltin dilaurate, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0105] Example 1

[0106] A supermatte polyester fiber, and its preparation method includes the following steps:

[0107] Step 1: Take 48 g of composite modified matting agent and add it to 100 g of ethylene glycol, ultrasonically disperse for 30 min to obtain a matting agent slurry; mix the obtained matting agent slurry with 1 kg of terephthalic acid, 0.5 kg of ethylene glycol, and 0.5 g of ethylene glycol antimony, stir at 70°C for 30 min, raise the temperature to 225°C, and carry out an esterification reaction for 120 min, with the pressure controlled at 90 kPa;

[0108] Step 2: Add 0.025 g of antimony acetate to the product of Step 1, raise the temperature to 265°C, control the pressure at 10 kPa, and carry out a pre-polycondensation reaction for 60 min;

[0109] Step 3: Raise the temperature to 280°C, control the pressure at 0.1 kPa, carry out a final polycondensation for 70 min, discharge the material, cool, pelletize, and obtain supermatte polyester chips;

[0110] Step 4: Add the supermatte polyester chips to a melt spinning machine for melt spinning, winding, and drawing to obtain supermatte polyester fibers; among them, the spinning temperature is 300°C, the winding speed is 1000 m / min, the draw ratio is 3 times, and the draw speed is 800 m / min.

[0111] Among them, the preparation method of the composite modified matting agent includes the following steps:

[0112] S1: Prepare aluminum-doped porous nano-titanium dioxide:

[0113] S1-1: Take 10 mL of tetrabutyl titanate and add it to 50 mL of ethanol, ultrasonically disperse for 10 min, and drop the obtained mixture into 300 mL of deionized water under stirring, and stir for 45 min;

[0114] S1-2: Add 2.13 g of aluminum nitrate and 50 mL of ethanol to the product of Step S1-1, then add 6.5 g of ammonium bicarbonate, stir for 30 min, add the obtained product to a reaction kettle, react at 220°C for 8 h, after cooling to room temperature, the product is centrifugally washed with ethanol, dried at 60°C for 12 h, then calcined at 450°C for 2 h, and ground after cooling to room temperature to obtain aluminum-doped porous nano-titanium dioxide;

[0115] S2. In-situ coat reduced carbon dots on the surface of aluminum-doped porous nano-titanium dioxide by hydrothermal method to prepare carbon dot-coated modified titanium dioxide particles:

[0116] S2-1. Take 0.5 g of aluminum-doped porous nano-titanium dioxide and 0.632 g of benzenesulfonic acid, add them into 100 mL of deionized water, and ultrasonically disperse for 30 min to obtain dispersion liquid 1.

[0117] S2-2. Take 0.528 g of vitamin C, 0.484 g of L-cysteine, 20 mL of ethanol, add them into 80 mL of deionized water, stir for 5 min, then add 0.966 g of chitosan with a deacetylation degree greater than 70%, and stir for 15 min to obtain dispersion liquid 2.

[0118] S2-3. Under stirring, add dispersion liquid 2 into dispersion liquid 1, ultrasonically disperse for 30 min to obtain a carbon dot precursor solution. Transfer the carbon dot precursor solution to a reaction kettle with a polytetrafluoroethylene inner lining, react at 170 °C for 14 h, cool to room temperature, then centrifuge and filter. Wash the solid product with ethanol and vacuum dry at 70 °C for 12 h to obtain carbon dot-coated modified titanium dioxide particles.

[0119] S3. Coat a polymer film on the surface of the carbon dot-coated modified titanium dioxide particles:

[0120] S3-1. Take 2.5 g of carbon dot-coated modified titanium dioxide particles and 1 g of sodium dodecylbenzenesulfonate, add them into 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nano-particle dispersion liquid.

[0121] S3-2. Take 6.5 g of methyl methacrylate, 1.5 g of polyurethane acrylate, 1.5 g of N-phenyl maleimide, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them and ultrasonically disperse for 10 min. Add the obtained mixture into the nano-particle dispersion liquid under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then dropwise add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution with the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain a composite modified matting agent.

[0122] Among them, the polyurethane acrylate is prepared by the following method:

[0123] S3-2-1. Take polyethylene glycol and add it to butyl acetate. Add 2,4-toluene diisocyanate and dibutyltin dilaurate dropwise in sequence under stirring. React at 68°C for 2h. After cooling to room temperature, add hydroxyethyl acrylate and hydroxyoctyl methacrylate. Continue to react at 72°C for 1h. Cool to room temperature to obtain a crude polyurethane acrylate product.

[0124] The molar ratio of 2,4-toluene diisocyanate: polyethylene glycol: hydroxyethyl acrylate: hydroxyoctyl methacrylate is 2:1:1.2:1, the mass of dibutyltin dilaurate is 0.5% of the mass of polyethylene glycol, and the mass of butyl acetate is 20% of the sum of the masses of 2,4-toluene diisocyanate, polyethylene glycol, hydroxyethyl acrylate and hydroxyoctyl methacrylate;

[0125] S3-2-2. The crude polyurethane acrylate product is precipitated with petroleum ether. After separation of the precipitate, it is dissolved with butyl acetate. The resulting mixture is then precipitated in petroleum ether. Finally, the precipitate is separated to obtain purified polyurethane acrylate.

[0126] Performance Characterization

[0127] 1. Reference Figure 1 , is the XRD spectrum of the aluminum-doped porous nano-titanium dioxide prepared in Example 1, which is consistent with the characteristic peak of anatase titanium dioxide. Combined with the appearance of the Al2O3 characteristic peak, it illustrates the successful synthesis of aluminum-doped porous nano-titanium dioxide.

[0128] 2. Reference Figure 2 , is the infrared absorption spectrum of the carbon dot-coated modified titanium dioxide particles prepared in Example 1, wherein the characteristic peaks of -NH, -OH, -SH, Benzene (benzene ring), C=O, S=O, CO and other functional groups are derived from the carbon dots, and the characteristic peaks of Ti-O and Al-O are derived from the inner core aluminum-doped porous nano-titanium dioxide, indicating the successful synthesis of the carbon dot-coated modified titanium dioxide particles.

[0129] 3. Antioxidant properties

[0130] The aluminum-doped porous nano-titanium dioxide (Al-TiO2) and carbon dot-coated modified titanium dioxide particles (Al-TiO2@CDs) prepared in Example 1 were tested for their antioxidant properties, and the test methods were as follows:

[0131] Al-TiO2 and Al-TiO2@CDs were added to ethanol respectively and ultrasonically dispersed for 30 min to prepare a dispersion with a concentration of 0.5 mg / mL. The DPPH free radical scavenging ability test kit (Cat. No. LE-1-168, Hefei Lyle Biotechnology Co., Ltd.) was used to detect the antioxidant properties of the dispersion within a certain period of time.

[0132] Principle of determination: DPPH free radicals have a single electron, and their alcohol solution is purple with a strong absorption at 515 nm. When there is an antioxidant present, the DPPH free radicals are scavenged, the color of the solution becomes lighter, and the absorbance at 515 nm decreases. Within a certain range, the change in absorbance is proportional to the degree of scavenging of free radicals. Specifically, the lower the absorbance at 515 nm, the stronger the antioxidant performance.

[0133] The test results are as Figure 3 shown. It can be seen from the test results that Al-TiO2 does not have antioxidant properties, while Al-TiO2@CDs exhibits excellent antioxidant properties, indicating that the antioxidant properties mainly come from the carbon dots coated on the outer layer.

[0134] Example 2

[0135] A super-dulling polyester fiber, and its preparation method includes the following steps:

[0136] Step 1: Take 48 g of the composite modified dulling agent and add it to 100 g of ethylene glycol, and ultrasonically disperse for 30 min to obtain a dulling agent slurry; mix the obtained dulling agent slurry with 1 kg of terephthalic acid, 0.5 kg of ethylene glycol, and 0.5 g of ethylene glycol antimony, stir at 80 °C for 30 min, raise the temperature to 215 °C, and carry out an esterification reaction for 130 min, with the pressure controlled at 100 kPa;

[0137] Step 2: Add 0.025 g of antimony acetate to the product of Step 1, raise the temperature to 270 °C, control the pressure at 11 kPa, and carry out a pre-polycondensation reaction for 65 min;

[0138] Step 3: Raise the temperature to 285 °C, control the pressure at 0.1 kPa, carry out a final polycondensation for 65 min, discharge the material, cool it, and pelletize it to obtain super-dulling polyester chips;

[0139] Step 4: Add the super-dulling polyester chips to a melt spinning machine for melt spinning, winding, and stretching to obtain super-dulling polyester fibers; among them, the spinning temperature is 300 °C, the winding speed is 1000 m / min, the stretching ratio is 3 times, and the stretching speed is 800 m / min.

[0140] Among them, the preparation method of the composite modified dulling agent includes the following steps:

[0141] S1. Prepare aluminum-doped porous nano-titanium dioxide:

[0142] S1-1: Take 10 mL of tetrabutyl titanate and add it to 50 mL of ethanol, ultrasonically disperse for 10 min, and drop the obtained mixture into 300 mL of deionized water under stirring, and stir for 45 min;

[0143] S1-2: Add 2.13 g of aluminum nitrate and 50 mL of ethanol to the product of step S1-1, then add 6.5 g of ammonium bicarbonate, stir for 30 min, add the obtained product to a reaction kettle, react at 220 °C for 8 h, after cooling to room temperature, the product is centrifugally washed with ethanol, dried at 60 °C for 12 h, then calcined at 450 °C for 2 h, and ground after cooling to room temperature to obtain aluminum-doped porous nano-titanium dioxide;

[0144] S2: In-situ coat reduced carbon dots on the surface of aluminum-doped porous nano-titanium dioxide by hydrothermal method to prepare carbon dot-coated modified titanium dioxide particles:

[0145] S2-1: Take 0.6 g of aluminum-doped porous nano-titanium dioxide and 0.632 g of benzenesulfonic acid, add them to 100 mL of deionized water, and ultrasonically disperse for 30 min to obtain dispersion liquid 1;

[0146] S2-2: Take 0.528 g of vitamin C, 0.484 g of L-cysteine, 20 mL of ethanol, add them to 80 mL of deionized water, stir for 5 min, then add 0.966 g of chitosan with a deacetylation degree greater than 70%, and stir for 15 min to obtain dispersion liquid 2;

[0147] S2-3: Under stirring, add dispersion liquid 2 to dispersion liquid 1, ultrasonically disperse for 30 min to obtain a carbon dot precursor solution, transfer the carbon dot precursor solution to a reaction kettle with a polytetrafluoroethylene inner lining, react at 170 °C for 14 h, after cooling to room temperature, centrifuge and filter, wash the solid product with ethanol, and vacuum dry at 70 °C for 12 h to obtain carbon dot-coated modified titanium dioxide particles;

[0148] S3: Coat a polymer film on the surface of the carbon dot-coated modified titanium dioxide particles:

[0149] S3-1: Take 2.2 g of carbon dot-coated modified titanium dioxide particles and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nano-particle dispersion liquid;

[0150] S3-2. Take 6.5 g of methyl methacrylate, 1.5 g of polyurethane acrylate, 1.5 g of N-phenyl maleimide, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them, and ultrasonically disperse for 10 min. Add the obtained mixture to the nanoparticle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then dropwise add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution having the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain the composite modified matting agent.

[0151] Among them, the preparation method of polyurethane acrylate is the same as that in Example 1.

[0152] Example 3

[0153] A super-matting polyester fiber, and its preparation method includes the following steps:

[0154] Step 1. Take 45 g of the composite modified matting agent and add it to 100 g of ethylene glycol, ultrasonically disperse for 30 min to obtain a matting agent slurry. Mix the obtained matting agent slurry with 1 kg of terephthalic acid, 0.5 kg of ethylene glycol, and 0.5 g of ethylene glycol antimony, stir at 70 °C for 30 min, raise the temperature to 230 °C, and carry out an esterification reaction for 110 min, with the pressure controlled at 90 kPa;

[0155] Step 2. Add 0.025 g of antimony acetate to the product of Step 1, raise the temperature to 260 °C, control the pressure at 10 kPa, and carry out a pre-polycondensation reaction for 60 min;

[0156] Step 3. Raise the temperature to 280 °C, control the pressure at 0.1 kPa, carry out a final polycondensation for 70 min, discharge the material, cool it, and pelletize it to obtain super-matting polyester chips;

[0157] Step 4. Add the super-matting polyester chips to a melt spinning machine for melt spinning, winding, and stretching to obtain super-matting polyester fibers; among them, the spinning temperature is 300 °C, the winding speed is 1000 m / min, the stretching ratio is 3 times, and the stretching speed is 800 m / min.

[0158] The preparation method of the composite modified matting agent is the same as that in Example 1.

[0159] Comparative Example 1

[0160] The difference between this example and Example 1 is only that: commercially available nano-titanium dioxide (average particle size 5 nm, anatase type, Nanjing Baokete New Materials Co., Ltd.) is used instead of the composite modified matting agent in Example 1, and the addition amount is changed to 24 g.

[0161] Comparative Example 2

[0162] The difference between this example and Example 1 is only that: in the preparation method of the composite modified matting agent, aluminum nitrate is not added in step S1-2.

[0163] Comparative Example 3

[0164] The difference between this example and Example 1 is only that: the preparation method of the composite modified matting agent includes the following steps:

[0165] S1. Prepare aluminum-doped porous nano-titanium dioxide, and the preparation method is the same as that in Example 1;

[0166] S2. Coating a polymer film on the surface of the aluminum-doped porous nano-titanium dioxide:

[0167] S2-1. Take 2.5 g of aluminum-doped porous nano-titanium dioxide and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nano-particle dispersion;

[0168] S2-2. Take 6.5 g of methyl methacrylate, 1.5 g of polyurethane acrylate, 1.5 g of N-phenyl maleimide, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them and ultrasonically disperse for 10 min; the obtained mixture is added to the nano-particle dispersion under stirring, and stirring is maintained. Nitrogen is introduced into the obtained mixed system for 30 min, and then 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate is added. React at 62 °C for 2 h, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution with the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain the composite modified matting agent.

[0169] Comparative Example 4

[0170] The difference between this example and Example 1 is only that: in this example, the carbon dot-coated modified titanium dioxide particles prepared in Example 1 are used as the composite modified matting agent, and the addition amount is 36 g.

[0171] Comparative Example 5

[0172] The difference between this example and Example 1 is only that: the preparation method of the composite modified matting agent includes the following steps:

[0173] S1. Prepare aluminum-doped porous nano-titanium dioxide, with the preparation method being the same as that in Example 1;

[0174] S2. In-situ coat reduced carbon dots on the surface of aluminum-doped porous nano-titanium dioxide by hydrothermal method to prepare carbon dot-coated modified titanium dioxide particles, with the preparation method being the same as that in Example 1;

[0175] S3. Coat a polymer film on the surface of the carbon dot-coated modified titanium dioxide particles:

[0176] S3-1. Take 2.5 g of carbon dot-coated modified titanium dioxide particles and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nano-particle dispersion;

[0177] S3-2. Take 6.5 g of methyl methacrylate, 1.5 g of N-phenylmaleimide, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them, and ultrasonically disperse for 10 min; add the obtained mixture to the nano-particle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of an aqueous potassium persulfate solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then add 10 mL of an aqueous potassium persulfate solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with a 3 wt% aluminum sulfate solution having the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain a composite modified matting agent.

[0178] Comparative Example 6

[0179] The difference between this example and Example 1 is only that: the preparation method of the composite modified matting agent includes the following steps:

[0180] S1. Prepare aluminum-doped porous nano-titanium dioxide, with the preparation method being the same as that in Example 1;

[0181] S2. In-situ coat reduced carbon dots on the surface of aluminum-doped porous nano-titanium dioxide by hydrothermal method to prepare carbon dot-coated modified titanium dioxide particles, with the preparation method being the same as that in Example 1;

[0182] S3. Coat a polymer film on the surface of the carbon dot-coated modified titanium dioxide particles:

[0183] S3-1. Take 2.5 g of carbon dot-coated modified titanium dioxide particles and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nano-particle dispersion;

[0184] S3-2: Take 6.5 g of methyl methacrylate, 1.5 g of polyurethane acrylate, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them, and ultrasonically disperse for 10 min; add the obtained mixture to the nanoparticle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then add dropwise 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution with the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain the composite modified matting agent.

[0185] Comparative Example 7

[0186] The difference between this example and Example 1 is only that: the preparation method of the composite modified matting agent includes the following steps:

[0187] S1: Prepare aluminum-doped porous nano-titanium dioxide, and the preparation method is the same as that in Example 1;

[0188] S2: Coating a polymer film on the surface of aluminum-doped porous nano-titanium dioxide:

[0189] S2-1: Take 2.5 g of aluminum-doped porous nano-titanium dioxide and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nanoparticle dispersion;

[0190] S2-2: Take 6.5 g of methyl methacrylate, g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them, and ultrasonically disperse for 10 min; add the obtained mixture to the nanoparticle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then add dropwise 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution with the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain the composite modified matting agent.

[0191] Performance Test

[0192] 1. Test the photocatalytic activities of the composite modified matting agent in Example 1, the nano-titanium dioxide in Comparative Example 1, and the composite modified matting agents in Comparative Examples 2-7, and the method is as follows:

[0193] At 25°C, 100 mg of the composite modified matting agent in Example 1, 100 mg of the nano-titanium dioxide in Comparative Example 1, and 100 mg of the composite modified matting agents in Comparative Examples 2-7 were respectively added to 100 mL of a rhodamine B solution with a concentration of 10 mg / L. They were ultrasonically dispersed for 30 min in the dark, irradiated for 24 h using a 200 W xenon lamp as the light source, and the absorbance of the rhodamine B solution before and after irradiation was measured with a spectrophotometer. The degradation rate was calculated according to the following formula:

[0194] Degradation rate = (C0 - C t ) / C0 × 100% = (A0 - A t ) / A0 × 100%, where C0 and A0 are the initial dye concentration and absorbance respectively; C t , A t are the dye concentration and absorbance respectively after the irradiation time t. The smaller the degradation rate, the lower the photocatalytic activity.

[0195] The test results are shown in Table 1 below and Figure 4 as follows:

[0196] Table 1

[0197] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Degradation rate / % 4.2 83.1 5.0 65.9 11.6 7.3 8.8 72.3

[0198] It can be seen from the test results that the photocatalytic activity of titanium dioxide was well inhibited in Example 1. In Comparative Examples 3 and 7, carbon dots were not coated, lacking the reducing ability provided by the carbon dots, and the photocatalytic activity of titanium dioxide was not effectively inhibited. Comparative Example 4 shows that the coating of the polymer film can have a certain blocking effect on the active substances generated by the photocatalysis of titanium dioxide.

[0199] 2. Test the properties of the polyester fiber products prepared in the test examples and comparative examples

[0200] 2-1. Matting performance

[0201] Using barium sulfate as a reference, the diffuse reflection signal of the polyester fiber sample to visible light was measured with an integrating sphere reflectance measuring instrument. The greater the diffuse reflectance, the better the matting performance.

[0202] 2-2. Mechanical properties

[0203] Referring to the standard "GB / T 14344-2022 Chemical Fibers - Test Method for Tensile Properties of Filaments", the breaking strength of the polyester fibers prepared in the test examples and comparative examples was measured.

[0204] 2-3. Resistance to light aging performance

[0205] Measuring the anti-photoaging performance of the polyester fibers prepared in the measurement examples and comparative examples: Ultraviolet irradiation treatment was adopted, with the distance between the ultraviolet lamp and the sample being 30 cm, the power being 40 W, and the ultraviolet light treatment lasting for 48 h; then, referring to the standard "GB / T 14344-2022 Chemical Fibers - Test Method for Tensile Properties of Filaments", the breaking strength after the light treatment was measured, and the breaking strength retention rate was calculated. The breaking strength retention rate = (breaking strength after the light treatment / breaking strength before the light treatment) × 100%.

[0206] The test results are shown in Table 2 below and Figure 5 - Figure 7 as follows:

[0207] Table 2

[0208] Visible light diffuse reflectance % Breaking strength (cN / detx) Retention rate of breaking strength after light treatment (%) Example 1 97.5 3.6 96.4 Example 2 97.1 3.6 96.0 Example 3 96.6 3.4 94.9 Comparative Example 1 78.9 1.8 73.1 Comparative Example 2 94.7 3.3 92.0 Comparative Example 3 90.4 3.2 81.7 Comparative Example 4 87.3 1.9 88.5 Comparative Example 5 92.1 2.7 90.9 Comparative Example 6 93.9 2.9 90.3 Comparative Example 7 84.0 2.3 78.2

[0209] By analyzing the test results, it can be seen that the polyester fibers prepared in Examples 1-3 have excellent matting performance, good mechanical strength, and excellent anti-photoaging performance. In Comparative Example 1, commercially available nano-titanium dioxide was used, and the problems of its photocatalytic activity and compatibility were not properly solved, resulting in a significant decline in comprehensive performance. In Comparative Example 2, the overall performance decreased slightly. In Comparative Example 3, the decrease in visible light diffuse reflectance was attributed to the lack of an increase in surface roughness due to the absence of carbon dot coating, and the reason for the decrease in its breaking strength was the lack of the free radical scavenging ability provided by the carbon dots, which led to a decrease in the thermal stability of the polyester during the preparation process, and the decrease in the breaking strength retention rate after the light treatment proved the inhibitory effect of the carbon dot coating on the photocatalytic activity of titanium dioxide. In Comparative Example 4, the polymer film coating was not used, seriously affecting the dispersion performance of the matting agent particles and resulting in a decrease in the performance improvement. The results of Comparative Examples 5 and 6 can illustrate from the side that doping polyurethane acrylate and N-phenyl maleimide in the polymer film can improve the thermal stability and coating strength of the polymer film. The comparison between the results of Comparative Example 7 and Comparative Example 4 shows that when polyurethane acrylate and N-phenyl maleimide are not doped in the polymer film, the coating barrier effect of the polymer film decreases, and the spillage of the oxidation active substances generated by the internal titanium dioxide increases, resulting in a decrease in the breaking strength retention rate after the light treatment.

[0210] Although the embodiments of the present invention have been disclosed as above, they are not limited to only the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details.

Claims

1. A super dull polyester fiber, characterized in that, It is obtained by spinning super-dulling polyester chips, and the super-dulling polyester chips are polymerized from terephthalic acid, ethylene glycol, a composite modified dulling agent and a catalyst as raw materials; The preparation method of the composite modified dulling agent includes the following steps: S1. Prepare aluminum-doped porous nano-titanium dioxide; S2. In-situ coat reduced carbon dots on the surface of aluminum-doped porous nano-titanium dioxide by hydrothermal method to obtain Carbon dot coating Modification titanium dioxide particles; S3. Coating a polymer film on the surface of titanium dioxide particles to obtain a composite modified matting agent; Carbon dot coating and modification ​ The polymer film is a polymethyl methacrylate polymer film doped and modified with polyurethane acrylate and N-phenyl maleimide.

2. The super dull polyester fiber according to claim 1, characterized in that, Step S1 is specifically as follows: S1-1. Take tetrabutyl titanate and add it to ethanol, and drop the obtained mixture into deionized water and stir; S1-2. Add aluminum nitrate and ethanol to the product of step S1-1, then add ammonium bicarbonate and stir. Add the obtained product to a reaction kettle and react under heating. Wash, dry and calcine the product to obtain aluminum-doped porous nano-titanium dioxide.

3. The supermatte polyester fiber according to claim 1, characterized in that, Step S2 is specifically as follows: S2-1. Take aluminum-doped porous nano-titanium dioxide, Add benzenesulfonic acid to deionized water and ultrasonically disperse to obtain dispersion liquid 1; S 2-2. Take Vitamin C, L-cysteine, and ethanol are added to deionized water, and after stirring, chitosan and stir to obtain dispersion liquid 2; dispersion liquid 2; S 2-3. Add dispersion liquid 2 to dispersion liquid 1 and ultrasonically disperse to obtain a carbon dot precursor solution. Transfer the carbon dot precursor solution to a reaction kettle, Heating react under [conditions not clear], centrifuge and filter, wash the solid product, and vacuum dry to obtain carbon dot coating and modification Titanium dioxide particles.

4. The super dull polyester fiber according to claim 1, wherein Step S3 is specifically as follows: S3-1. Take Carbon dot coating and modification Titanium dioxide particles and an emulsifier are added to deionized water, and ultrasonic dispersion is performed to obtain a nanoparticle dispersion; S3-2. Take methyl methacrylate, polyurethane acrylate, N-phenyl maleimide, n-pentanol, an emulsifier, and deionized water and mix them, and ultrasonically disperse; add the obtained mixture to the nano-particle dispersion liquid under stirring, add potassium persulfate, and heat to react. After the reaction is completed, demulsify, filter by suction, wash and dry the solid product to obtain a composite modified dulling agent; The emulsifier is sodium dodecylbenzenesulfonate.

5. The super dull polyester fiber according to claim 2, wherein Step S1 is specifically as follows: S1-1. Take 5-20 mL of tetrabutyl titanate and add it to 25-100 mL of ethanol, ultrasonically disperse for 5-30 min, and drop the obtained mixture into 150-600 mL of deionized water under stirring and stir for 30-90 min; S1-2. Add 1.065-4.26 g of aluminum nitrate and 25-100 mL of ethanol to the product of step S1-1, then add 3.25-13 g of ammonium bicarbonate and stir for 15-60 min. Add the obtained product to a reaction kettle and react at 200-240 °C for 4-16 h. After cooling to room temperature, wash the product by centrifugation with ethanol, dry at 50-70 °C for 6-24 h, and then calcine at 420-550 °C for 1-4 h. After cooling to room temperature, grind to obtain aluminum-doped porous nano-titanium dioxide.

6. The super dull polyester fiber according to claim 3, characterized in that, Step S2 is specifically as follows: S2-1. Take 0.25 - 1 g of aluminum-doped porous nano-titanium dioxide and 0.316 - 1.264 g Add benzenesulfonic acid to 50-200 mL of deionized water and ultrasonically disperse for 15-60 min to obtain dispersion liquid 1; S 2-2. Take 0.264-1.056 0.242 - 0.968 g of vitamin C, 0.242 - 0.968 g of L-cysteine, 10 - 40 mL of ethanol are added to 40 - 160 mL of deionized water. After stirring for 5 - 15 min, 0.483-1.932 g of chitosan with a degree of deacetylation greater than 70% and stir for 5- 30 min to obtain dispersion liquid 2; S 2-3. Add dispersion liquid 2 to dispersion liquid 1 under stirring and ultrasonically disperse for 15-60 min to obtain a carbon dot precursor solution. Transfer the carbon dot precursor solution to a reaction kettle with a polytetrafluoroethylene inner lining and react at 150-190 °C for 7-24 h. After cooling to room temperature, centrifuge Heart filtration, the solid product is washed with ethanol and vacuum dried at 60 - 75°C for 6 - 24 h to obtain carbon dot-coated modification Titanium dioxide particles.

7. The supermatte polyester fiber according to claim 4, characterized in that, Step S3 is specifically as follows: S3-1. Take 1.25 - 5 g Carbon dot-coated modification of titanium dioxide particles and 0.5 - 2 g of sodium dodecylbenzenesulfonate, add them to 25 - 100 mL of deionized water, and ultrasonically disperse for 15 - 60 min to obtain a nanoparticle dispersion; S3-2: Take 3.25 - 13 g of methyl methacrylate, 0.75 - 3 g of polyurethane acrylate, 0.75 - 3 g of N-phenyl maleimide, 1 - 4 g of n-pentanol, 1.5 - 6 g of sodium dodecylbenzenesulfonate, and 50 - 200 g of deionized water, mix them and ultrasonically disperse for 5 - 20 min; add the obtained mixture to the nanoparticle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 15 - 60 min, then add 5 - 20 mL of potassium persulfate aqueous solution containing 0.125 - 0.5 g of potassium persulfate, react at 60 - 65°C for 1 - 4 h, then dropwise add 5 - 20 mL of potassium persulfate aqueous solution containing 0.125 - 0.5 g of potassium persulfate, raise the temperature to 70 - 75°C, react for 0.5 - 2 h, then raise the temperature to 78 - 82°C, react for 0.5 - 2 h, stop heating, demulsify with 3 wt% aluminum sulfate solution, filter by suction, wash the solid product with ethanol, and vacuum dry at 50 - 80°C for 12 - 48 h to obtain the composite modified matting agent; Among them, the polyurethane acrylate is prepared by the following method: S3-2-1: Take polyethylene glycol and add it to butyl acetate, sequentially dropwise add 2,4-toluene diisocyanate and dibutyltin dilaurate under stirring, react at 60 - 70°C for 1 - 4 h, after cooling to room temperature, add hydroxyethyl acrylate and hydroxyoctyl methacrylate, continue to react at 70 - 78°C for 0.5 - 2 h, and cool to room temperature to obtain the crude polyurethane acrylate product; S3-2-2: Purify the crude polyurethane acrylate product to obtain polyurethane acrylate.

8. The super-dull polyester fiber according to claim 1, wherein The preparation method of the composite modified matting agent includes the following steps: S1: Prepare aluminum-doped porous nano-titanium dioxide: S1-1: Take 10 mL of tetrabutyl titanate and add it to 50 mL of ethanol, ultrasonically disperse for 10 min, and add the obtained mixture dropwise to 300 mL of deionized water under stirring, and stir for 45 min; S1-2: Add 2.13 g of aluminum nitrate and 50 mL of ethanol to the product of step S1-1, then add 6.5 g of ammonium bicarbonate, stir for 30 min, add the obtained product to a reaction kettle, react at 220°C for 8 h, after cooling to room temperature, wash the product by centrifugation with ethanol, dry at 60°C for 12 h, then calcine at 450°C for 2 h, and grind after cooling to room temperature to obtain aluminum-doped porous nano-titanium dioxide; S2. Preparation Carbon dot-coated modification Titanium dioxide particles: S2-1. Take 0.5 g of aluminum-doped porous nano-titanium dioxide and 0.632 g Add benzene sulfonic acid to 100 mL of deionized water and ultrasonically disperse for 30 min to obtain dispersion liquid 1; S 2-2: Take 0.528 0.484 g of vitamin C, 0.484 g of L-cysteine, and 20 mL of ethanol were added to 80 mL of deionized water. After stirring for 5 min, 0.966 g of chitosan with a degree of deacetylation greater than 70%, stir for 15 min to obtain dispersion liquid 2; S 2-3: Add dispersion liquid 2 to dispersion liquid 1 under stirring, ultrasonically disperse for 30 min to obtain the carbon dot precursor solution, transfer the carbon dot precursor solution to a reaction kettle with a polytetrafluoroethylene inner lining, react at 170°C for 14 h, after cooling to room temperature, centrifuge and filter, wash the solid product with ethanol, and vacuum dry at 70°C for 12 h to obtain carbon dot-coated modification Titanium dioxide particles; S3. Coating with a polymer film: S3-1. Take 2.5 g Coating modification with carbon dots of titanium dioxide particles and 1 g of sodium dodecylbenzenesulfonate, add them to 50 mL of deionized water, and ultrasonically disperse for 30 min to obtain a nanoparticle dispersion; S3-2. Take 6.5 g of methyl methacrylate, 1.5 g of polyurethane acrylate, 1.5 g of N-phenyl maleimide, 2 g of n-pentanol, 3 g of sodium dodecylbenzenesulfonate, and 100 g of deionized water, mix them, and ultrasonically disperse for 10 min; add the obtained mixture to the nanoparticle dispersion under stirring, keep stirring, pass nitrogen into the obtained mixed system for 30 min, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, react at 62 °C for 2 h, then add 10 mL of potassium persulfate aqueous solution containing 0.25 g of potassium persulfate, raise the temperature to 72 °C, react for 1 h, then raise the temperature to 78 °C, react for 1 h, stop heating, demulsify with 3 wt% aluminum sulfate solution of the same volume as the product, filter by suction, wash the solid product with ethanol, and vacuum dry at 60 °C for 24 h to obtain a composite modified matting agent; Among them, the polyurethane acrylate is prepared by the following method: S3-2-1. Take polyethylene glycol and add it to butyl acetate. Stir and sequentially add 2,4-toluene diisocyanate and dibutyltin dilaurate, react at 68 °C for 2 h, after cooling to room temperature, add 2-hydroxyethyl acrylate and 2-hydroxyoctyl methacrylate, and continue to react at 72 °C for 1 h, then cool to room temperature to obtain a crude polyurethane acrylate product; Among them, the molar ratio of 2,4-toluene diisocyanate: polyethylene glycol: 2-hydroxyethyl acrylate: 2-hydroxyoctyl methacrylate is 2:1:1.2:1, the mass of dibutyltin dilaurate is 0.5% of the mass of polyethylene glycol, and the mass of butyl acetate is 20% of the sum of the masses of 2,4-toluene diisocyanate, polyethylene glycol, 2-hydroxyethyl acrylate, and 2-hydroxyoctyl methacrylate; S3-2-2. Precipitate the crude polyurethane acrylate product with petroleum ether, dissolve the separated precipitate with butyl acetate, place the obtained mixture in petroleum ether for precipitation again, and finally separate the precipitate to obtain the purified polyurethane acrylate.

9. A method for preparing a super-dull polyester fiber according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1. Take the composite modified matting agent and add it to ethylene glycol, ultrasonically disperse to obtain a matting agent slurry; mix the matting agent slurry with terephthalic acid, ethylene glycol, and a catalyst, stir under heating, and raise the temperature for esterification reaction; Step 2. Add a catalyst, raise the temperature for pre-polycondensation reaction; Step 3. Raise the temperature for final polycondensation, discharge the material, cool, pelletize to obtain super-matting polyester chips; Step 4. Add the super-matting polyester chips to a melt spinning machine for melt spinning, winding, and stretching to obtain super-matting polyester fibers; Among them, the catalyst is one or several of zinc acetate, magnesium acetate, calcium acetate, ethylene glycol, antimony acetate, and antimony trioxide.

10. The preparation method of the super dull polyester fiber according to claim 9, characterized in that, It includes the following steps: Step 1. Take 24-96 g of the composite modified matting agent and add it to 50-200 g of ethylene glycol, ultrasonically disperse for 15-60 min to obtain a matting agent slurry; mix the obtained matting agent slurry with 0.5-2 kg of terephthalic acid, 0.25-1 kg of ethylene glycol, and 0.25-1 g of ethylene glycol antimony, stir at 60-80 °C for 15-60 min, raise the temperature to 200-250 °C, carry out esterification reaction for 60-240 min, and control the pressure at 50-110 kPa; Step 2: Add 0.0125 - 0.05 g of antimony acetate, raise the temperature to 255 - 270 °C, control the pressure at 5 - 15 kPa, and carry out pre-polycondensation reaction for 30 - 90 min; Step 3: Raise the temperature to 280 - 295 °C, control the pressure at 0.05 - 0.3 kPa, carry out final polycondensation for 30 - 100 min, discharge the material, cool it, pelletize it to obtain super-dull polyester chips; Step 4: Add the super-dull polyester chips into a melt spinning machine for melt spinning, winding, and drawing to obtain super-dull polyester fibers.

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