Preparation method of novel polyester titanium catalyst and application of novel polyester titanium catalyst in polyester synthesis

Abstract

The invention discloses a preparation method of a novel polyester titanium catalyst, which comprises the following steps: hydrolyzing silicate ester, condensing to form nano particles, covalently bonding a ligand of the catalyst to a side chain of silanol, and then adding ammonia water to catalyze mutual condensation of silanol to obtain nano particles with smaller particle size; after a titanium source and a cocatalyst are added, the ligands on the surfaces of the nano particles are rapidly complexed and coordinated with titanium atoms and cocatalytic atoms, and the atoms are anchored on the nano particles, so that the nano particle type catalyst suitable for bright and semi-dull polyester systems is obtained. The synthesis method is convenient to operate, simple and feasible, the raw materials are easy to obtain, the synthesis process is mild, the prepared product has the advantages of being environmentally friendly, low in price, stable in performance and the like, energy consumption and material consumption during industrial production of polyester filaments can be reduced, cost reduction and efficiency improvement are facilitated, and industrial application and popularization of titanium catalysts in polyester and fiber industries are promoted.

Description

Technical Field

[0001] The invention relates to the technical field of polyester synthesis, and in particular to a preparation method of a novel polyester titanium catalyst and application thereof in polyester synthesis. Background Art

[0002] The current annual production capacity of the polyester industry is nearly 80 million tons, and related final products such as fiber filaments, films, and packaging boxes have been used in all aspects of production and life. Polyester, such as its main variety polyethylene terephthalate (PET), requires the use of catalysts (ester exchange catalysts / condensation catalysts) to promote the occurrence of ester exchange reactions and promote the growth of polyester molecular weight to ensure good processability of polyester melt and reasonable mechanical strength and durability of the product. The catalysts currently used in the industry are usually heavy metal antimony (Sb) catalysts. The polyester produced will precipitate a certain amount of heavy metal antimony during its subsequent application, processing, and landfill, polluting water bodies and the natural environment, causing a certain degree of harm to humans and animals.

[0003] Considering the economic feasibility and physical properties of the final polyester product, it is generally believed that only titanium-based catalysts are most likely to replace heavy metal antimony-based catalysts and be applied on a large scale in the polyester industry. Although germanium-based catalysts have excellent performance and the resulting polyester has a good hue, their high prices are difficult to accept in bulk product areas such as polyester filaments. They can only be accepted to a certain extent in some niche areas, and their large-scale application is limited. Although titanium-based catalysts have broad prospects, their industrial application still has certain technical bottlenecks, such as crystallization rate problems and catalytic activity problems in semi-light systems.

[0004] The amount of titanium catalyst added is small, the system is highly clean, and there is no possibility of being reduced by ethylene glycol to form nanoparticles during the polycondensation process (antimony catalysts may be reduced to form antimony nanoparticles during the polymerization process, which can subsequently become polyester nucleation crystallization promoters). However, the existing titanium catalysts do not have the effect of nucleating agents, which leads to a significant decrease in the crystallization rate and ability of all-titanium polyester, affecting polyester-related products such as the condensed structure and mechanical properties of filaments. When the crystallization rate needs to be increased, additional structures such as silica nucleating agents need to be added. From the production perspective of PET filaments and stretch yarns, the crystallization behavior of polyester significantly affects the related spinning process and stretching process. In view of the large scale of the current processing of all-antimony polyester filaments and stretching, the process system is mature and there is little possibility of significant adjustments. Only when the condensed behavior and properties of titanium polyester are close to those of the current conventional antimony system, can it be switched without feeling, smoothly transitioned, and accepted by downstream customers when applied on a large scale. Otherwise, there is great resistance to its large-scale industrial application and the possibility of promotion and use is small. Therefore, one of the main contents of this work is to improve the problem of decreased crystallization ability of polyester after the introduction of titanium catalyst. The specific solution is to develop a catalyst that can act as a catalyst during polymerization to catalyze the ester exchange reaction to produce polyester; and after polymerization, it can act as a nucleating crystallization agent to promote polyester crystallization.

[0005] In the field of polyester fibers, the glossiness of semi-matte polyester filaments is between glossy and matte, presenting a soft, natural appearance and high market acceptance. At present, conventional titanium catalysts can exert their catalytic activity well in the light system. However, once the semi-matte system is applied, a significant problem will arise, that is, there is basically no catalytic activity. The main reason is that the introduction of titanium dioxide and other related additives in the matting agent inhibits the catalytic activity of titanium. Since semi-matte polyester filaments account for the majority of filament production capacity, it is crucial to ensure the activity and economic use of titanium catalysts in semi-matte polyester systems for the promotion of titanium catalysts. The second main content of this work is to significantly improve the activity of nanoparticle titanium catalysts in titanium dioxide (TiO 2 ) The catalytic activity in the presence of nanoparticles and other substances meets the production requirements of bright polyester and semi-dull polyester, while ensuring that the hue of the polyester is within the market acceptable range. Summary of the invention

[0006] In order to solve one or some technical problems existing in the prior art, one of the purposes of the present application is to provide a method for preparing a novel polyester titanium catalyst. The synthesis method is convenient, simple and feasible, and the prepared product has the advantages of being green, environmentally friendly and inexpensive. By introducing a co-catalyst, the chemical environment of the titanium atom in the catalytic center and the potential on the surface of the nanoparticles are regulated, the inhibitory effect of titanium dioxide and other components in the matting agent on the catalytic activity of the titanium catalyst is weakened or basically eliminated, thereby ensuring the applicability and economic use of the titanium catalyst in the semi-matt polyester system.

[0007] The second purpose of the present application is to provide a new type of semi-matt polyester titanium catalyst for use in polyester synthesis. Since the nanoparticles have the ability to catalyze and promote crystallization at the same time, they can reflect the catalytic ability of ester exchange reaction after addition, and can also significantly increase the nucleation sites of polyester crystallization, improve the nucleation and crystallization ability of titanium-based polyester, and improve the crystallization rate and ability of titanium-based polyester, so as to ensure that titanium-based polyester can basically match the current spinning, stretching and other processes, effectively reduce the resistance to promotion, and promote the industrial application of titanium-based catalysts.

[0008] In order to solve the above existing technical problems, one of the purposes of this application is achieved by adopting the following technical solution:

[0009] A method for preparing a novel polyester titanium catalyst, the preparation method comprising:

[0010] S1, dissolving a conventional silicate compound and an epoxy silicate compound in a solvent, stirring until a uniform and stable solution is formed, to obtain a solution A, wherein the solvent is at least one of ethylene glycol, diethylene glycol, butanol, and ethanol;

[0011] S2, adding an organic ligand compound to the solution A in step S1, so that the organic ligand in the organic ligand compound reacts with the silanol with a functional group in the solution A to achieve covalent bonding, thereby obtaining a solution B;

[0012] S3, gradually adding hydrochloric acid aqueous solution to the above solution B, stirring continuously and heating, then stirring the mixed solution evenly and reacting it at 50-210° C. for 1-48 hours, so that the silicate compound is hydrolyzed, judging the hydrolysis progress according to the amount of liquid distilled, and obtaining a short-term stable silanol solution C;

[0013] S4, adding a catalyst-dosed ammonia water to the solution C in step S3 to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby obtaining a dispersion D;

[0014] S5, water, remove the water and ammonia contained in the dispersion D by heating, then add a titanium source and a co-catalyst, and the organic ligands on the surface of the nanoparticles react with the titanium source and the co-catalyst to obtain a dispersion E, which is a mixture of the catalyst and alcohol by-products; the introduction of the co-catalyst can significantly improve the catalytic activity of the obtained nanoparticle-type catalyst in the presence of titanium dioxide nanoparticles, thereby ensuring its applicability in a semi-dull polyester system.

[0015] S6, the dispersion E in step S5 is centrifuged and washed with deionized water to obtain a white slurry pre-product F;

[0016] S7, dispersing the pre-product F in deionized water, stirring and dispersing for 0.1 to 3 hours, performing high-speed shearing treatment for 0.1 to 3 hours using a high-speed disperser, and then grinding for 0.5 to 5 hours using a sand mill to obtain a finished catalyst product.

[0017] When the novel polyester titanium catalyst is prepared by the above method, the ligand of the catalyst is covalently bonded to the side chain of silanol after the silicate is hydrolyzed and before condensation to form nanoparticles, and then ammonia water at a catalyst dosage is added to catalyze the mutual condensation between silanols to obtain nanoparticles with smaller particle size. After the titanium source and the co-catalyst are added, the ligand on the surface of the nanoparticles quickly complexes and coordinates with the titanium atoms and the co-catalyst atoms and fixes these atoms on the nanoparticles to obtain a nanoparticle-type catalyst suitable for light and semi-dull polyester systems. The catalytic center is the titanium atom, and the co-catalyst atom is mainly used to adjust the chemical environment of the catalytic center and the surface potential of the nanoparticles, so that the catalyst will not have a phenomenon of catalyst activity reduction due to the introduction of titanium dioxide, and the catalytic activity can be well maintained in the semi-light polyester system. At the same time, since the catalyst itself is a nanoparticle, after the polyester completes the polycondensation, the catalyst will become the crystallization nucleation center of the polyester, promote the crystallization of the polyester, ensure that the condensed state behavior of the all-titanium polyester is close to that of the all-antimony polyester, and reduce the back-end resistance when the titanium catalyst is used. The synthesis method adopted in this work is convenient, simple and feasible to operate, the raw materials are easily available and the synthesis process is mild. The prepared product has the advantages of being green, environmentally friendly, low-priced and having stable performance. It can reduce the energy consumption and catalyst consumption in the industrial production of polyester filaments, which is beneficial to reducing costs and increasing efficiency, and is conducive to promoting the industrial application and promotion of titanium-based catalysts in the textile industry.

[0018] Preferably, the conventional silicate compound in step S1 is at least one of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, tetrapentyl orthosilicate, tetra(2-ethylbutyl)silicate, tetra(isopropyl)silicate, tetra(2-methoxyethanol)silicate, tetra(2-ethylbutyl)silicate, tetra(2-ethylhexyl)silicate, tetraoctyl silicate, tetraphenyl silicate, and tetradecoxysilicon.

[0019] Preferably, the epoxy silicate compound in step S1 is at least one of 3-glycidyl propoxy trimethoxysilane, 3-glycidyl ether oxypropyl triethoxy silane, 3-glycidyl propoxy tripropoxy silane, and 3-glycidyl propoxy tributoxy silane.

[0020] Preferably, the molar ratio of the conventional silicate compound to the epoxy-containing silicate compound is 1-9:9-1, and the mass ratio of the total silicate compound to the solvent A is 1-4:9-6.

[0021] Preferably, the molar ratio of the conventional silicate compound to the epoxy-containing silicate compound is 2-7:8-3.

[0022] In the process of preparing the novel polyester titanium catalyst by the above method, silanol mainly comes from two silicon sources, one of which is a conventional silicon source, namely tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, tetrapentyl orthosilicate, tetra(2-ethylbutyl) silicate, tetra(isopropyl) silicate, tetra(2-methoxyethanol) silicate, tetra(2-ethylbutyl) silicate, tetra(2-ethylhexyl) silicate, tetraoctyl silicate, tetraphenyl silicate, and at least one of tetradecyloxysilane. By controlling the amount of these two silicon sources, the amount of stable side chains can be effectively controlled, and the effective regulation of the particle size of the nanoparticles can be achieved. An excessively high proportion of conventional silicate compounds will result in too few ligands introduced into the entire system, so that the titanium content in the catalyst finally prepared is low and the catalytic activity is poor. Since the nanoparticles lack effective stabilizing groups, the particle size will be larger; an excessively low proportion of conventional silicate compounds will result in too many ligands introduced. The ligand has the function of stabilizing the nanoparticles, thus significantly reducing the particle size, or even not producing nanoparticles, but the product is directly dissolved in the aqueous phase system, and the catalyst yield will be very low or no limited product will be obtained.

[0023] Preferably, the reaction temperature in step S2 is 100-200° C., and the reaction time is 1-5 h.

[0024] Preferably, the organic ligand compound in step S2 includes at least one of hydrolyzed polymaleic anhydride (molecular weight 400-800), citric acid, oxalic acid, gluconic acid, di-o-vanillin (diphenyl ether) phenylimine, and nitrilotriacetic acid.

[0025] Preferably, in step S2, the molar ratio of the silanol with epoxy group to the organic ligand compound is 2-8:8-2.

[0026] Preferably, in step S2, the molar ratio of the silanol with epoxy group to the organic ligand compound is 3-8:7-2.

[0027] Preferably, the catalytic reaction temperature in step S4 is 30-200° C., the reaction time is 1-5 h, and the particle size of the formed nanoparticles is 5-300 nanometers.

[0028] Since the existing chain segments are relatively long (new chain segments generated after the glycidyl ether oxypropyl chain segments react with the organic ligand compound) and have good compatibility with water, the particle size of the obtained nanoparticles is between 5 and 300 nanometers, the particle size is in the nanometer range, and the formed particles are relatively small.

[0029] Preferably, the reaction temperature in step S5 is 100-200° C., the reaction time is 1-24 h, and the titanium source is at least one of tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, tetra-tert-butyl titanate, and 2-ethyl-1-hexanol titanium.

[0030] Preferably, the co-catalyst in step S5 is at least one of calcium lactate, calcium acetate, calcium citrate, calcium chloride, aluminum acetate, aluminum chloride, aluminum lactate, aluminum citrate, aluminum sulfate, magnesium lactate, magnesium acetate, magnesium citrate, and magnesium chloride. The introduction of the co-catalyst effectively regulates the chemical environment of the catalytically active central atom and the surface potential of the nanoparticles, and can effectively protect the catalytic activity of the titanium catalyst from being affected by the matting agent in the semi-matting system; preferably, the molar ratio of the silanol with epoxy group to the titanium source in step S5 is 5-9:5-1.

[0031] Preferably, in step S5, the molar ratio of the silanol with epoxy group to the titanium source is 6-9:4-1.

[0032] Preferably, in step S5, the mass ratio of titanium element to promoter metal element is 9-7:1-3.

[0033] Preferably, the catalyst particles in the finished catalyst product in step S7 have a particle size of 5 to 300 nm, the main component of the dispersion medium is deionized water, and the percentage of the effective substance Ti is 0.5% to 30%.

[0034] Preferably, the solid content of the catalyst product in step S7 is 2-15%, the titanium content is 0.5% to 6%, and the additive metal content is 0.1% to 4%.

[0035] Preferably, the sand mill grinding time in step S7 is 0.5-4.5 h, the solid content of the finished catalyst is 2-14%, and the titanium content is 0.5% to 4.5%.

[0036] The second purpose of this application is achieved by the following technical solution:

[0037] Application of a novel semi-extinction polyester titanium catalyst in polyester synthesis, the application method comprising:

[0038] A1. Add the novel polyester titanium catalyst finished product and dibasic acid into a diol solution at a temperature of 20 to 120° C. and stir rapidly until a uniform and stable mixed dispersion is formed;

[0039] A2, using diol and dibasic acid as raw materials to carry out esterification, pre-polycondensation and final polycondensation in sequence to prepare polyester in the form of chips, filaments or staple fibers, wherein the reaction temperature of the polyester is 220-280° C., the reaction pressure is 30 Pa-0.4 MPa, and the reaction time is 3.5-10.0 h;

[0040] A3. The mixed dispersion is added before esterification or polycondensation of the polyester synthesis. The added amount of the new polyester titanium catalyst product is calculated based on the amount of titanium element. The content of the effective substance Ti in the added new polyester titanium catalyst product in the polyester is 1-100ppm.

[0041] Titanium atoms with catalytic activity are coordinated and complexed on nanoparticles, so the nanoparticles have catalytic ability and can act as a catalyst for transesterification during polyester synthesis. Due to the small particle size and large specific surface area, the catalytic activity is relatively high. After the catalysis is completed, the nanoparticles are evenly distributed in the polyester, acting as heterogeneous nucleating agents and promoters to promote polyester nucleation and crystallization, change the condensed structure of polyester, and improve mechanical properties. Due to the small particle size, more nucleation sites are introduced per unit mass, and the ability to promote crystallization nucleation is greater. Since nanoparticles have both the ability to catalyze and promote crystallization, they can reflect the catalytic ability of transesterification reaction after addition, and can also significantly increase the nucleation sites of polyester crystallization, improve the nucleation and crystallization ability of titanium polyester, and improve the crystallization behavior of titanium polyester.

[0042] Preferably, the polyester includes at least one of polyethylene terephthalate, polybutylene terephthalate and polybutylene adipate.

[0043] Preferably, the dibasic acid includes at least one of purified terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, succinic acid, adipic acid, biphenyl dicarboxylic acid, and cyclohexane dicarboxylic acid; the diol includes at least one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,4-cyclohexanedimethanol; and the molar ratio of the dibasic acid to the diol is 1:1.2 to 2.0.

[0044] Preferably, the esterification temperature of the raw materials of the diol and the dibasic acid in step A2 is 220-260°C, the esterification pressure is normal pressure-0.4 MPa, and the esterification time is 2.0-4.0 h; the pre-polycondensation temperature is 260-280°C, the vacuum degree is 100-150 Pa, and the reaction time is 1.0-3.5 h; the final polycondensation temperature is 270-290°C, the vacuum degree is 5-80 Pa, and the reaction time is 1.0-3.5 h.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. In view of the difference in crystallization behavior between titanium polyester and antimony polyester, the main characteristics of nanoparticle titanium catalyst are: the silanol covalently bonded to the organic ligand undergoes condensation reaction under the catalysis of ammonia water to form nanoparticles. At the same time, most of the organic ligand chain segments extend in the solvent to stabilize the formed nanoparticles, making the particle size small and uniform. The catalytic center titanium atom is coordinated to the organic ligand of the nanoparticle, so the nanoparticle has the ability to catalyze the ester exchange of polyester in the polycondensation stage. Because the relevant ligand has a good ability to stabilize the titanium atom, the catalyst has excellent hydrolysis resistance and the ability to catalyze side reactions has been significantly suppressed, and the polyester produced has a good hue.

[0047] 2. Aiming at the problem of significant decrease in catalytic activity of titanium catalyst in semi-light system, the surface potential of nanoparticles and the chemical environment of titanium atoms are optimized by introducing co-catalysts, so that the interaction between the matting agent (titanium dioxide and other substances) and the catalytic active center is weakened, the phenomenon of deactivation of the catalytic active center is avoided, and the catalytic activity of the catalyst is effectively retained. However, the amount of co-catalyst introduced needs to be reasonably regulated. Excessive addition will lead to a decrease in the melt quality of semi-light polyester, such as a widening of the molecular weight distribution and accelerated degradation, resulting in a decrease in the processability of polyester such as spinnability. The synthetic method adopted is convenient, simple and feasible, and the prepared product has the advantages of green environmental protection and low price. It can be used in light polyester system and semi-matt polyester system, and has a significant effect on promoting polyester crystallization, which is conducive to promoting the industrial application and promotion of titanium catalysts in the textile industry.

[0048] 3. After polymerization, the catalyst nanoparticles still remain in the polyester system and are evenly dispersed in the polyester system. They can serve as the nucleation center of the crystal to change the crystallization kinetics and corresponding physical properties of the obtained polyester. The nanoparticle catalyst prepared by this method integrates catalysis and nucleation functions. When used in the synthesis of titanium polyester, the titanium polyester and antimony polyester can have similar crystallization temperatures without negatively affecting the polymerization rate and polyester hue. This enables titanium polyester to basically adapt to the current processing technology, provides convenience for subsequent applications, effectively reduces promotion resistance, reduces the promotion cost of titanium catalysts, and promotes the industrial application of titanium catalysts. DETAILED DESCRIPTION

[0049] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0050] Embodiment 1:

[0051] A novel polyester titanium catalyst synthesis and dispersion process: wherein the solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0052] (1) Dissolve 12.5 g of tetraethyl orthosilicate and 16.71 g of 3-glycidyloxypropyltriethoxysilane in 146.02 g of diethylene glycol, and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63 g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding, to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) 15.12g of 5% hydrochloric acid aqueous solution is gradually added to the above solution B, and the mixture is stirred continuously. Then the mixed solution is stirred evenly and placed at 50°C for 2h to hydrolyze the silicate compound to obtain a short-term stable silanol solution C; (4) 22.68g of 10% ammonia water is added to solution C to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby forming a dispersion D; (5) The water and ammonia in the dispersion D are removed by heating, and 2.88g of calcium acetate is added. The organic ligand on the surface of the nanoparticles reacts with the titanium source for complexation, and then 77.21g of tetrabutyl titanate is added to react with the nanoparticles in the dispersion to produce butanol byproducts, thereby obtaining dispersion E, which is a mixture of the catalyst and the butanol byproducts; (6) the dispersion E is centrifuged and washed 6-8 times with deionized water to obtain a white slurry pre-product G; (7) the pre-product F is dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hour using a high-speed disperser, and then ground for 3 hours using a sand mill to obtain a finished catalyst. The particle size of the catalyst particles is between 50-200nm, the dispersion medium is water, the percentage of the effective substance (Ti) is 0.95%, and the amount of the catalyst (titanium, Ti) added for polyester synthesis is calculated as 5ppm of the amount of polyester produced.

[0053] A novel semi-dull polyester titanium catalyst is used in polyester synthesis, wherein the dibasic acid is purified terephthalic acid and the diol is ethylene glycol. The application method includes:

[0054] 333.3g of purified terephthalic acid, 160g of ethylene glycol, 1.76g of matting agent (55% solid content) and finished catalyst dispersion were added to the reactor, and nitrogen was replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water reached the theoretical value, the pre-polycondensation and final polycondensation reactions were started; wherein, the esterification temperature was 230-240°C, the pressure was normal pressure-0.4MPa, and the esterification time was 2.5h; the pre-polycondensation temperature was 265°C, the vacuum degree was 100-150Pa, and the reaction time was 1.0h; the final polycondensation temperature was 272°C, the vacuum degree was 5-20Pa, and the reaction time was 1.5h, until the stirring power reached the set value, and the material was cut into slices.

[0055] Example 2

[0056] Synthesis and dispersion process of a new polyester titanium catalyst:

[0057] The solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0058] (1) Dissolve 12.5 g of tetraethyl orthosilicate and 16.71 g of 3-glycidyloxypropyltriethoxysilane in 146.02 g of diethylene glycol, and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63 g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding, to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) 15.12g of 5% hydrochloric acid aqueous solution is gradually added to the above solution B, and the mixture is stirred continuously. Then the mixed solution is stirred evenly and placed at 50°C for 2h to hydrolyze the silicate compound to obtain a short-term stable silanol solution C; (4) 22.68g of 10% ammonia water is added to solution C to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby forming a dispersion D; (5) The water and ammonia in the dispersion D are removed by heating, and 5.77g of calcium acetate is added. The organic ligand on the surface of the nanoparticles reacts with the titanium source for complexation, and then 77.21g of tetrabutyl titanate is added to react with the nanoparticles in the dispersion to produce butanol byproducts, thereby obtaining dispersion E, which is a mixture of the catalyst and the butanol byproducts; (7) the dispersion E is centrifuged with deionized water and washed 6-8 times to obtain a white slurry pre-product G; (7) the pre-product F is dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hour using a high-speed disperser, and then ground with a sand mill for 3 hours to obtain a finished catalyst. The particle size of the catalyst particles is between 50-200nm, the dispersion medium is water, the percentage of the effective substance (Ti) is 0.94%, and the amount of the catalyst (titanium, Ti) added for polyester synthesis is calculated as 5ppm of the amount of polyester produced.

[0059] Polyester Synthesis:

[0060] The dibasic acid is taken as an example of purified terephthalic acid, and the diol is taken as an example of ethylene glycol. 333.3g of purified terephthalic acid, 160g of ethylene glycol, 1.76g of matting agent (55% solid content) and the finished catalyst dispersion are added into the reactor, and the nitrogen is replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water reaches the theoretical value, the above dispersion is added to start the pre-condensation and final polycondensation reactions; wherein, the esterification temperature is 230-240°C, the esterification pressure is normal pressure-0.4MPa, and the esterification time is 2.5h; the pre-condensation temperature is 265°C, the vacuum degree is 100-150Pa, and the reaction time is 1.0h; the final polycondensation temperature is 272°C, the vacuum degree is 5-20Pa, and the reaction time is 1.5h, until the stirring power reaches the set value, and the material is cut into slices.

[0061] Example 3

[0062] Synthesis and dispersion process of a new polyester titanium catalyst:

[0063] The solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0064] (1) Dissolve 12.5 g of tetraethyl orthosilicate and 16.71 g of 3-glycidyloxypropyltriethoxysilane in 146.02 g of diethylene glycol, and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63 g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding, to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) 15.12g of 5% hydrochloric acid aqueous solution is gradually added to the above solution B, and the mixture is stirred continuously. Then the mixed solution is stirred evenly and placed at 50°C for 2h to hydrolyze the silicate compound to obtain a short-term stable silanol solution C; (4) 22.68g of 10% ammonia water is added to solution C to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby forming a dispersion D; (5) The water and ammonia in the dispersion D are removed by heating, and 8.65g of calcium acetate is added. The organic ligand on the surface of the nanoparticles reacts with the titanium source for complexation, and then 77.21g of tetrabutyl titanate is added to react with the nanoparticles in the dispersion to produce butanol byproducts, thereby obtaining dispersion E, which is a mixture of the catalyst and the butanol byproducts; (6) the dispersion E is centrifuged with deionized water and washed 6-8 times to obtain a white slurry pre-product G; (7) the pre-product F is dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hour using a high-speed disperser, and then ground with a sand mill for 3 hours to obtain a finished catalyst. The particle size of the catalyst particles is between 50-200nm, the dispersion medium is water, the percentage of the effective substance (Ti) is 0.92%, and the amount of the catalyst (titanium, Ti) added for polyester synthesis is calculated as 5ppm of the amount of polyester produced.

[0065] Polyester Synthesis:

[0066] The dibasic acid is taken as purified terephthalic acid, and the diol is taken as ethylene glycol. 333.3g purified terephthalic acid, 160g ethylene glycol, 1.76g matting agent (55% solid content) and catalyst finished dispersion are added into a reactor, and the nitrogen is replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reaches the theoretical value, the pre-polycondensation and final polycondensation reactions are started; wherein, the esterification temperature is 230-240°C, the esterification pressure is normal pressure-0.4MPa, and the esterification time is 2.5h; the pre-polycondensation temperature is 265°C, the vacuum degree is 100-150Pa, and the reaction time is 1.0h; the final polycondensation temperature is 272°C, the vacuum degree is 5-20Pa, and the reaction time is 1.0h, until the stirring power reaches the set value, and the material is discharged and granulated into slices.

[0067] Example 4

[0068] Synthesis and dispersion process of a new polyester titanium catalyst:

[0069] The solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0070] (1) Dissolve 12.5 g of tetraethyl orthosilicate and 16.71 g of 3-glycidyloxypropyltriethoxysilane in 146.02 g of diethylene glycol, and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63 g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding, to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) 15.12g of 5% hydrochloric acid aqueous solution is gradually added to the above solution B, and the mixture is stirred continuously. Then the mixed solution is stirred evenly and placed at 50°C for 2h to allow the silicate compound to hydrolyze to obtain a short-term stable silanol solution C; (4) 22.68g of 10% ammonia water is added to solution C to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby forming a dispersion D; (5) The water and ammonia in the dispersion D are removed by heating, and then 11.54g of calcium acetate is added. , so that the organic ligand on the surface of the nanoparticles reacts with the titanium source for complexation, and then 77.21g of tetrabutyl titanate is added to react with the nanoparticles in the dispersion to produce butanol byproducts, and dispersion E is obtained, which is a mixture of the catalyst and the butanol byproducts; (6) the dispersion E is centrifuged with deionized water and washed 6-8 times to obtain a white slurry pre-product G; (7) the pre-product F is dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hours using a high-speed disperser, and then ground by a sand mill for 3 hours to obtain a finished catalyst. Wherein, the particle size of the catalyst particles is between 50-200nm, the dispersion medium is water, the percentage of the effective substance (Ti) is 0.90%, and the amount of catalyst (titanium, Ti) added for polyester synthesis is calculated as 5ppm of the amount of polyester produced.

[0071] Polyester Synthesis:

[0072] The dibasic acid is taken as purified terephthalic acid, and the diol is taken as ethylene glycol. 333.3g purified terephthalic acid, 160g ethylene glycol, 1.76g matting agent (55% solid content) and catalyst finished dispersion are added into a reactor, and the nitrogen is replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reaches the theoretical value, the pre-polycondensation and final polycondensation reactions are started; wherein, the esterification temperature is 230-240°C, the esterification pressure is normal pressure-0.4MPa, and the esterification time is 2.5h; the pre-polycondensation temperature is 265°C, the vacuum degree is 100-150Pa, and the reaction time is 1.0h; the final polycondensation temperature is 272°C, the vacuum degree is 5-20Pa, and the reaction time is 1.0h, until the stirring power reaches the set value, and the material is discharged and granulated into slices.

[0073] Example 5

[0074] Synthesis and dispersion process of a new polyester titanium catalyst:

[0075] The solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0076] (1) Dissolve 12.5 g of tetraethyl orthosilicate and 16.71 g of 3-glycidyloxypropyltriethoxysilane in 146.02 g of diethylene glycol, and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63 g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding, to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) 15.12g of 5% hydrochloric acid aqueous solution is gradually added to the above solution B, and the mixture is stirred continuously. Then the mixed solution is stirred evenly and placed at 50°C for 2h to allow the silicate compound to hydrolyze to obtain a short-term stable silanol solution C; (4) 22.68g of 10% ammonia water is added to solution C to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby forming a dispersion D; (5) The water and ammonia in the dispersion D are removed by heating, and then 14.59g of magnesium acetate is added. , so that the organic ligand on the surface of the nanoparticles reacts with the titanium source for complexation, and then 77.21g of tetrabutyl titanate is added to react with the nanoparticles in the dispersion to produce butanol byproducts, and dispersion E is obtained, which is a mixture of the catalyst and the butanol byproducts; (6) the dispersion E is centrifuged with deionized water and washed 6-8 times to obtain a white slurry pre-product G; (7) the pre-product F is dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hours using a high-speed disperser, and then ground by a sand mill for 3 hours to obtain a finished catalyst. Among them, the particle size of the catalyst particles is between 50-200nm, the dispersion medium is water, the percentage of the effective substance (Ti) is 0.87%, and the amount of catalyst (titanium, Ti) added for polyester synthesis is calculated as 5ppm of the amount of polyester produced.

[0077] Polyester Synthesis:

[0078] The dibasic acid is taken as purified terephthalic acid, and the diol is taken as ethylene glycol. 333.3g purified terephthalic acid, 160g ethylene glycol, 1.76g matting agent (55% solid content) and catalyst finished dispersion are added into a reactor, and the nitrogen is replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reaches the theoretical value, the pre-polycondensation and final polycondensation reactions are started; wherein, the esterification temperature is 230-240°C, the esterification pressure is normal pressure-0.4MPa, and the esterification time is 2.5h; the pre-polycondensation temperature is 265°C, the vacuum degree is 100-150Pa, and the reaction time is 1.0h; the final polycondensation temperature is 272°C, the vacuum degree is 5-20Pa, and the reaction time is 1.0h, until the stirring power reaches the set value, and the material is discharged and granulated into slices.

[0079] Example 6

[0080] Synthesis and dispersion process of a new polyester titanium catalyst:

[0081] The solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0082] (1) Dissolve 12.5 g of tetraethyl orthosilicate and 16.71 g of 3-glycidyloxypropyltriethoxysilane in 146.02 g of diethylene glycol, and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63 g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding, to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) 15.12g of 5% hydrochloric acid aqueous solution is gradually added to the above solution B, stirring continuously, and then the mixed solution is stirred evenly and placed at 50°C for 2h to allow the silicate compound to hydrolyze to obtain a short-term stable silanol solution C; (4) 22.68g of 10% ammonia water is added to solution C to catalyze the condensation of semi-stable silanols to form nanoparticles, forming a dispersion D; (5) The water and ammonia in the dispersion D are removed by heating, and then 20.01g of aluminum lactate is added , so that the organic ligand on the surface of the nanoparticles reacts with the titanium source for complexation, and then 77.21g of tetrabutyl titanate is added to react with the nanoparticles in the dispersion to produce butanol byproducts, and dispersion E is obtained, which is a mixture of the catalyst and the butanol byproducts; (6) the dispersion E is centrifuged with deionized water and washed 6-8 times to obtain a white slurry pre-product G; (7) the pre-product F is dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hours using a high-speed disperser, and then ground by a sand mill for 3 hours to obtain a finished catalyst. Among them, the particle size of the catalyst particles is between 50-200nm, the dispersion medium is water, the percentage of the effective substance (Ti) is 0.84%, and the amount of catalyst (titanium, Ti) added for polyester synthesis is calculated as 5ppm of the amount of polyester produced.

[0083] Polyester Synthesis:

[0084] The dibasic acid is taken as purified terephthalic acid, and the diol is taken as ethylene glycol. 333.3g purified terephthalic acid, 160g ethylene glycol, 1.76g matting agent (55% solid content) and catalyst finished dispersion are added into a reactor, and the nitrogen is replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reaches the theoretical value, the pre-polycondensation and final polycondensation reactions are started; wherein, the esterification temperature is 230-240°C, the esterification pressure is normal pressure-0.4MPa, and the esterification time is 2.5h; the pre-polycondensation temperature is 265°C, the vacuum degree is 100-150Pa, and the reaction time is 1.0h; the final polycondensation temperature is 272°C, the vacuum degree is 5-20Pa, and the reaction time is 1.0h, until the stirring power reaches the set value, and the material is discharged and granulated into slices.

[0085] Comparative Example 1

[0086] Synthesis and dispersion process of common nanoparticle titanium catalyst:

[0087] The solvent is diethylene glycol, the conventional silicate compound is tetraethyl orthosilicate, the epoxy silicate compound is 3-glycidyloxypropyltriethoxysilane, the organic ligand compound is citric acid, and the titanium source is tetrabutyl tetratitanate. The preparation method comprises the following steps:

[0088] (1) Dissolve 12.5g of tetraethyl orthosilicate and 16.71g of 3-glycidyloxypropyltriethoxysilane in 146.02g of diethylene glycol and stir until a uniform and stable solution is formed to obtain solution A; (2) Add 11.63g of citric acid, an organic ligand compound, to solution A to react the organic ligand with the silicate with functional groups to achieve covalent bonding to obtain solution B. The reaction temperature is 150°C and the reaction time is 2h; (3) Add 15.12g of 5% hydrochloric acid aqueous solution to the above solution B gradually and stir continuously, then stir the mixed solution evenly and place it at 50°C for 2h to react so that the silicate compound is hydrolyzed to obtain a short-term stable silanol solution C; (4) Add ammonia water to 22.68g of 10% solution C to catalyze the mutual condensation of semi-stable silanols to form nanoparticles to form a dispersion D; (5) Heat and remove water and ammonia in the dispersion D. Then, 77.21g of tetrabutyl titanate was added, and the organic ligand on the surface of the nanoparticles reacted with the titanium source to form a complex coordination reaction, thereby obtaining a dispersion E, which was a mixture of a catalyst and alcohol byproducts; (6) The dispersion E was centrifuged and washed 8 times with deionized water to obtain a white slurry pre-product F; (7) The pre-product F was dispersed in deionized water, stirred and dispersed for 1 hour, and then subjected to high-speed shear treatment for 0.5 hours using a high-speed disperser, and then ground using a sand mill for 3 hours to obtain a finished catalyst. The particle size of the catalyst particles was between 5-50nm, the dispersion medium was water, the percentage of the effective substance (Ti) was 1%, and the amount of the catalyst added to the polyester synthesis was calculated as 5ppm of the amount of polyester produced.

[0089] 333.3g of purified terephthalic acid, 160g of ethylene glycol, 1.76g of matting agent (55% solid content) and finished catalyst dispersion (170ppm) were added to the reactor, and nitrogen was replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reached the theoretical value, the pre-polycondensation and final polycondensation reactions were started; wherein, the esterification temperature was 230-240°C, the esterification pressure was normal pressure-0.4MPa, and the esterification time was 2.5h; the pre-polycondensation temperature was 265°C, the vacuum degree was 100-150Pa, and the reaction time was 1.0h; the final polycondensation temperature was 275°C, the vacuum degree was 5-20Pa, and the reaction time was 1.5h, until the stirring power reached the set value, and the material was discharged and pelletized into slices.

[0090] Comparative Example 2

[0091] 333.3g of purified terephthalic acid, 160g of ethylene glycol and the finished catalyst dispersion liquid of Comparative Example 1 (5ppm) were added to the reactor, and nitrogen was replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reached the theoretical value, the pre-polycondensation and final polycondensation reactions were started; wherein, the esterification temperature was 230-240°C, the esterification pressure was normal pressure-0.4MPa, and the esterification time was 2.5h; the pre-polycondensation temperature was 265°C, the vacuum degree was 100-150Pa, and the reaction time was 1.0h; the final polycondensation temperature was 272°C, the vacuum degree was 5-20Pa, and the reaction time was 1.0h, until the stirring power reached the set value, and the material was cut into pellets to make slices.

[0092] Comparative Example 3

[0093] 333.3g of purified terephthalic acid, 160g of ethylene glycol, 1.76g of matting agent (55% solid content) and 0.012g of tetraisopropyl titanate (5ppm) were added to a reaction kettle, and nitrogen was replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reached the theoretical value, the pre-polycondensation and final polycondensation reactions were started; wherein, the esterification temperature was 230-240°C, the esterification pressure was normal pressure-0.4MPa, and the esterification time was 2.5h; the pre-polycondensation temperature was 265°C, the vacuum degree was 100-150Pa, and the reaction time was 1.0h; the final polycondensation temperature was 272°C, the vacuum degree was 5-20Pa, and the reaction time was 1.0h, until the stirring power reached the set value, and the material was discharged and pelletized into slices.

[0094] Comparative Example 4

[0095] 333.3g of purified terephthalic acid, 160g of ethylene glycol, 1.76g of matting agent (55% solid content) and 0.117g of ethylene glycol antimony (170ppm) were added to a reaction kettle, and nitrogen was replaced 3 times and then filled to 0.15MPa for esterification reaction. After the esterification water output reached the theoretical value, the pre-polycondensation and final polycondensation reactions were started; wherein, the esterification temperature was 230-240°C, the esterification pressure was normal pressure-0.4MPa, and the esterification time was 2.5h; the pre-polycondensation temperature was 265°C, the vacuum degree was 100-150Pa, and the reaction time was 1.0h; the final polycondensation temperature was 272°C, the vacuum degree was 5-20Pa, and the reaction time was 1.0h, until the stirring power reached the set value, and the material was discharged and pelletized into slices.

[0096] Comparative Example 5

[0097] 333.3 g of purified terephthalic acid, 160 g of ethylene glycol and the catalyst product dispersion prepared in Example 5 were added to the reactor. After nitrogen was replaced 3 times, nitrogen was filled to 0.15 MPa for esterification reaction. After the esterification water output reached the theoretical value, the pre-polycondensation and final polycondensation reactions were started; wherein, the esterification temperature was 230-240° C., the esterification pressure was normal pressure-0.4 MPa, and the esterification time was 2.5 h; the pre-polycondensation temperature was 265° C., the vacuum degree was 100-150 Pa, and the reaction time was 1.0 h; the final polycondensation temperature was 272° C., the vacuum degree was 5-20 Pa, and the reaction time was 1.0 h, until the stirring power reached the set value, and the material was discharged and pelletized into slices.

[0098] The corresponding semi-dull polyester product indicators of the above Examples 1 to 6 and Comparative Examples 1 to 3 were tested: intrinsic viscosity, crystallization temperature, L value and b value were tested according to GB / T 14189-2015. The polymerization time and test results are shown in the following table:

[0099]

[0100]

[0101] Comparative Examples 1, 2 and 3 clearly show that the catalytic activity of conventional titanium catalysts in semi-extinction systems is significantly reduced due to the presence of matting agents, resulting in a significant extension of the polymerization time, and the catalytic capacity is far inferior to that of antimony catalysts (Comparative Example 3).

[0102] By comparing Examples 1, 2, 3, and 4, when a co-catalyst is added during the synthesis of the catalyst, the catalytic activity of the nanoparticle-type titanium catalyst in the semi-light system is significantly improved, that is, the time required for polycondensation is gradually shortened to achieve the same polyester intrinsic viscosity (IV). By comparing Examples 4, 5, and 6, it can be seen that the addition of magnesium acetate has a more significant effect, or in other words, when the same amount is added, the co-catalyst magnesium acetate has the most significant effect on improving the catalytic activity of the titanium catalyst in the semi-light extinction system.

[0103] Examples 1, 2, 3, 4, 5, 6 and Comparative Example 5 show that the catalyst developed in this patent is suitable for glossy and semi-dull polyester systems and can be used for the production of these two polyesters.

[0104] The raw materials and equipment involved in the present invention, unless otherwise specified, are all commonly used raw materials and equipment; the preparation methods involved in the present invention, unless otherwise specified, are all conventional methods used in the art.

[0105] The nanoparticles prepared by this synthesis method have both the functions of catalyst and nucleating agent. The synthesis process is simple and feasible, and the addition process is convenient to operate. Its main components have the advantages of being non-toxic, green and environmentally friendly, and low in cost, which fully meets the current industry development needs and has a significant promoting effect on the promotion and application of titanium catalysts.

[0106] The above-mentioned implementation modes are only preferred implementation modes of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present application shall fall within the scope of protection required by the present application.

Claims

1. A method for preparing a novel polyester titanium catalyst, characterized in that: The preparation method comprises S1, dissolving a conventional silicate compound and an epoxy silicate compound in a solvent, stirring until a uniform and stable solution is formed, to obtain a solution A, wherein the solvent is at least one of ethylene glycol, diethylene glycol, butanol, and ethanol; S2, adding an organic ligand compound to the solution A in step S1, so that the organic ligand in the organic ligand compound reacts with the silanol with a functional group in the solution A to achieve covalent bonding, thereby obtaining a solution B; S3, gradually adding hydrochloric acid aqueous solution to the above solution B, stirring continuously and heating, then stirring the mixed solution evenly and reacting it at 50-210° C. for 1-48 hours, so that the silicate compound is hydrolyzed, judging the hydrolysis progress according to the amount of liquid distilled, and obtaining a short-term stable silanol solution C; S4, adding a catalyst-dosed ammonia water to the solution C in step S3 to catalyze the mutual condensation of semi-stable silanols to form nanoparticles, thereby obtaining a dispersion D, wherein the particle size of the particles is less than 500 microns; S5, removing water and ammonia contained in the dispersion D by heating, then adding a titanium source and a co-catalyst, and the organic ligands on the surface of the nanoparticles react with the titanium source and the co-catalyst to obtain a dispersion E, which is a mixture of the catalyst and alcohol by-products; S6, the dispersion E in step S5 is centrifuged and washed with deionized water to obtain a white slurry pre-product F; S7, dispersing the pre-product F in deionized water, stirring and dispersing for 0.1 to 3 hours, performing high-speed shearing treatment for 0.1 to 3 hours using a high-speed disperser, and then grinding for 0.5 to 5 hours using a sand mill to obtain a finished catalyst product.

2. The method for preparing a novel polyester titanium catalyst according to claim 1, characterized in that: The molar ratio of the conventional silicate compound to the epoxy-containing silicate compound is 1-9:9-1, and the mass ratio of the total silicate compound to the solvent A is 1-4:9-6.

3. The method for preparing a novel polyester titanium catalyst according to claim 2, characterized in that: In the step S2, the molar ratio of the silanol with epoxy group to the organic ligand compound is 2-8:8-2.

4. The method for preparing a novel polyester titanium catalyst according to any one of claims 1 to 3, characterized in that: The catalytic reaction temperature in step S4 is 30-200° C., the reaction time is 1-5 hours, and the particle size of the formed nanoparticles is 5-300 nanometers.

5. The method for preparing a novel polyester titanium catalyst according to claim 4, characterized in that: The reaction temperature in step S5 is 100-200° C., the reaction time is 1-24 hours, the titanium source is at least one of tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, tetra-tert-butyl titanate, and 2-ethyl-1-hexyl titanium; the molar ratio of the silanol with an epoxy group to the titanium source is 5-9:5-1.

6. The method for preparing a novel polyester titanium catalyst according to claim 4, characterized in that: The co-catalyst is at least one of calcium lactate, calcium acetate, calcium citrate, calcium chloride, aluminum acetate, aluminum chloride, aluminum lactate, aluminum citrate, aluminum sulfate, magnesium lactate, magnesium acetate, magnesium citrate, and magnesium chloride; 7. The method for preparing a novel polyester titanium catalyst according to claim 1, characterized in that: The catalyst particles in the finished catalyst product in step S7 have a particle size of 5 to 300 nm, the main component of the dispersion medium is deionized water, the percentage of the effective substance Ti is 0.5% to 30%, and the percentage of the promoter metal is 0.1% to 15%.

8. The method for preparing a novel polyester titanium catalyst according to claim 6, characterized in that: The solid content of the finished catalyst in step S7 is 2-18%, and the titanium content is 0.5% to 5%.

9. Application of a novel semi-dull polyester titanium catalyst in polyester synthesis, characterized in that: The application method comprises A1. Add the finished product of the novel polyester titanium catalyst as claimed in any one of claims 1 to 7 and the dibasic acid into a diol solution at a temperature of 20 to 120° C. and stir rapidly until a uniform and stable mixed dispersion is formed; A2, using diol and dibasic acid as raw materials to carry out esterification, pre-polycondensation and final polycondensation in sequence to prepare polyester in the form of chips, filaments or staple fibers, wherein the reaction temperature of the polyester is 220-280° C., the reaction pressure is 30 Pa-0.4 MPa, and the reaction time is 3.5-10.0 h; A3. The mixed dispersion is added before esterification or polycondensation of the polyester synthesis. The added amount of the new polyester titanium catalyst product is calculated based on the amount of titanium element. The content of the effective substance Ti in the added new polyester titanium catalyst product in the polyester is 1-100ppm.

10. The use of a novel semi-dull polyester titanium catalyst in polyester synthesis according to claim 9, characterized in that: The dibasic acid includes at least one of purified terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, succinic acid, adipic acid, biphenyl dicarboxylic acid, and cyclohexane dicarboxylic acid; the diol includes at least one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,4-cyclohexanedimethanol; The molar ratio of the dibasic acid to the diol is 1:1.2-2.0.

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