Polybutylene terephthalate as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polybutylene terephthalate production, in particular to polybutylene terephthalate as well as a preparation method and application thereof. The preparation method comprises the following steps: performing catalytic esterification, polycondensation and erucic acid grafting reaction through a compound catalyst A (titanium-germanium catalyst) and a compound catalyst B (yttrium-cerium-tetrabutyl titanate), forming a ternary conductive network by combining the carbon nanotubes, zinc oxide and graphene, and adding auxiliaries such as maleic anhydride grafted polypropylene and zinc stearate for blending. The volume resistivity of the obtained material is as low as 10-10 omegacm, the water absorption rate is less than or equal to 0.3%, and the thermal deformation temperature is increased to 160-180 DEG C. The material is used for an intelligent driving sensor shell, is subjected to high-speed mixing, twin-screw extrusion and injection molding, has high hydrophobicity and excellent processability, and meets the requirements of precise electronic components in a high-temperature and high-humidity environment.

Description

Technical Field

[0001] The invention relates to the technical field of polybutylene terephthalate production, in particular to polybutylene terephthalate and a preparation method and application thereof. Background Art

[0002] As a semi-crystalline thermoplastic engineering plastic, polybutylene terephthalate (PBT) is widely used in the field of automotive parts due to its excellent mechanical strength, chemical corrosion resistance, dimensional stability and good processing performance. However, the housing of smart driving sensors places higher requirements on materials: Conductive properties: It must meet the requirements of electromagnetic shielding (≥30dB) and electrostatic discharge. The volume resistivity of traditional PBT is as high as 10 15 Ω·cm, unable to build an effective conductive path; Environmental tolerance: The high temperature and high humidity (85℃ / 85%RH) environment of the engine compartment requires the material to be resistant to hydrolysis and aging. Conventional PBT has a high water absorption rate (0.8%), and long-term service is prone to mechanical performance degradation due to ester bond hydrolysis; Precision processing: The sensor housing size accuracy requirement is ±0.05mm. Traditional PBT has a low heat deformation temperature (60-80℃) and poor melt fluidity, which makes it difficult to meet the needs of precision injection molding.

[0003] In the prior art, in order to improve these properties of PBT, although attempts have been made to add conductive fillers (such as carbon nanotubes) or introduce hydrophobic groups, there are still a series of problems. Chinese patent application CN117295784A, published on December 26, 2023, discloses a polybutylene terephthalate composition and product, which comprises (A) 40% to 99.8% by weight of polybutylene terephthalate, (B) 0.2% to 10% by weight of at least one conductive filler selected from the group consisting of carbon nanotubes, carbon nanostructures and combinations thereof, and (C) 0% to 50% by weight of glass fiber, each based on the total weight of the polybutylene terephthalate composition, wherein each of these carbon nanostructures comprises a plurality of carbon nanotubes, which are branched, cross-linked, and / or share common walls with each other. The conductivity of PBT is enhanced by carbon nanotubes, thereby improving the electromagnetic shielding performance of the material. However, it only improves the conductivity and does not significantly improve the basic properties of the material, especially mechanical strength and hydrophobicity. Moreover, the synergistic effect between the hydrophobic modification of existing materials and the conductive filler is insufficient, making it difficult to achieve good conductivity and hydrophobicity at the same time. This makes it difficult to obtain a PBT material that can effectively prevent hydrolysis and has good conductivity in practical applications. Summary of the invention

[0004] In view of the above deficiencies in the prior art, the object of the present invention is to provide a polybutylene terephthalate, which achieves high conductivity, strong electromagnetic shielding, high hydrophobicity and environmental stability while maintaining excellent mechanical properties through composite catalysis, filler synergy and hydrophobic integrated design, and is suitable for precision electronic components in high temperature and high humidity environments.

[0005] The purpose of the present invention is to provide a method for preparing polybutylene terephthalate, which solves the limitations of traditional PBT and improves the comprehensive performance of the material by optimizing aspects such as raw material processing, reaction conditions and catalyst use.

[0006] The third object of the present invention is to provide an application of polybutylene terephthalate for the production of intelligent driving sensor housings.

[0007] The present invention is achieved by adopting the following technical solutions: The preparation method of polybutylene terephthalate comprises the following steps: (1) Add terephthalic acid and 1,4-butanediol into a reactor at a molar ratio of 1:1.2, add composite catalyst A, raise the temperature to 210-230°C, carry out esterification reaction, react for 2-4 hours, then raise the temperature to 240-260°C, carry out polycondensation reaction, react for 3-6 hours, and obtain polybutylene terephthalate base polymer; (2) blending an antioxidant with a polybutylene terephthalate base polymer in a twin-screw extruder to obtain an intermediate, then mixing the surface-treated carbon nanotubes and the modified zinc oxide in a mass ratio of (1-3):1, and blending them with the intermediate in a twin-screw extruder, wherein the temperature of each section of the extruder is set to 230-250° C. and the screw speed is 200-400 r / min to obtain a polybutylene terephthalate base polymer having conductivity; (3) adding the product obtained in step (2) and erucic acid in a mass ratio of 10:1 into a reaction kettle, then adding the composite catalyst B and phosphite, introducing nitrogen protection, heating to 190-210° C. under stirring, reacting for 4-4.5 hours, then washing and drying the product to obtain a hydrophobic polybutylene terephthalate base polymer; (4) adding the product obtained in step (3), maleic anhydride, an organic phosphate nucleating agent, a fatty acid ester lubricant, an ultraviolet absorber and a hindered amine light stabilizer into a twin-screw extruder for blending, and setting the temperature of each section of the extruder to 230-250° C. to obtain polybutylene terephthalate; The compound catalyst A is a titanium-germanium compound catalyst; the compound catalyst B is a yttrium-cerium-tetrabutyl titanate compound catalyst.

[0008] The amount of the composite catalyst A added is 0.2-0.5% of the total mass of the reactants in step (1); the total amount of the carbon nanotubes and zinc oxide added in step (2) is 3-7% of the total mass of the reactants in step (2); the amount of the phosphite added is 0.1-0.3% of the total mass of the reactants in step (3); the amount of the antioxidant added is 0.3-1% of the mass of the polybutylene terephthalate base polymer in step (2); the amount of maleic anhydride added is 1-3% of the mass of the product obtained in step (3); the amount of the organic phosphate nucleating agent added is 0.5-2% of the mass of the product obtained in step (3); the amount of the fatty acid ester lubricant added is 0.3-1% of the mass of the product obtained in step (3); the amount of the ultraviolet absorber added is 0.5-1% of the mass of the product obtained in step (3); and the amount of the hindered amine light stabilizer added is 0.5-1% of the mass of the product obtained in step (3).

[0009] The preparation method of the composite catalyst A comprises the following steps: ① Dissolve 10g of hexadecyltrimethylammonium bromide in deionized water and stir at 40-60°C until completely dissolved; add ammonia water to adjust the pH value to 9-11, then add 40-60ml of ethyl orthosilicate dropwise, and continue stirring to react for 2-6h; filter and wash the reaction product, and then dry it at 110°C for 18h; finally calcine at 500-600°C for 4-6h to obtain a porous silica carrier; ② Take materials according to the molar ratio of titanium to germanium (3-8):1, dissolve tetrabutyl titanate in anhydrous ethanol to form a titanium solution; put germanium dioxide in a container, add 30-37% concentrated hydrochloric acid and heat to 50-80°C to dissolve, forming a germanium solution; under stirring, add the germanium solution dropwise to the titanium solution, continue stirring for 1-3 hours, and obtain a titanium-germanium composite solution; ③ Take the material according to the lithium: titanium molar ratio (0.01-0.1):1, dissolve it in deionized water to prepare a lithium solution; ④ Premix the lithium solution and the titanium-germanium composite solution to obtain a mixed solution; add the porous silica carrier to the mixed solution and stir at room temperature for 6-12 hours; distill under reduced pressure to remove the solvent to obtain a solid product; dry the solid product at 105-110° C. for 15-20 hours, and then calcine at 300-500° C. for 2-4 hours to obtain a composite catalyst A.

[0010] The surface treatment method of the carbon nanotubes is as follows: placing the carbon nanotubes in a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, using 10-20 ml of the mixed acid per gram of carbon nanotubes, ultrasonically treating at 40-50° C. for 2-3 hours, and then washing with deionized water until neutral.

[0011] The method for modifying zinc oxide comprises the following steps: a. Take silane and solvent in a ratio of 1-3wt%, add to an ethanol / water mixture, add glacial acetic acid dropwise to adjust the pH to 4-5, and stir magnetically for 30-60min; b. Dry the zinc oxide powder at 100-120°C for 2-4h; c. Add the dried zinc oxide to the mixed solution obtained in step a at a mass ratio of 1:(10-20), and perform ultrasonic treatment at 40-50°C for 2-3h; d. The mixture obtained in step c is centrifuged, the supernatant is removed, the precipitate is washed with anhydrous ethanol 3-5 times, and the washed ZnO is vacuum dried at 80-100°C for 6-12h to obtain silanized zinc oxide.

[0012] The preparation method of the composite catalyst B comprises the following steps: Ⅰ. After calcining yttrium oxide and cerium oxide at 500-700℃ for 1-3h, add them into anhydrous ethanol and perform ultrasonic dispersion for 30-45min; Ⅱ. Tetrabutyl titanate is added to a container, and then the product obtained in step Ⅰ is added to a container containing tetrabutyl titanate, and the mixture is poured while stirring at a stirring speed of 300 r / min for 1-1.5 h to obtain a composite catalyst precursor solution; III. The composite catalyst precursor solution is sealed and aged at room temperature for 20-24 hours. The total mass concentration of tetrabutyl titanate, yttrium oxide and cerium oxide in the aged solution is 10-20%, and the composite catalyst B is obtained.

[0013] The mass ratio of tetrabutyl titanate, yttrium oxide and cerium oxide is 1:(0.1-1):0.5; the active ingredients of the composite catalyst B are tetrabutyl titanate, yttrium oxide and cerium oxide, and the amount of the active ingredients added is 0.05-0.2% of the total mass of the reactants in step (3).

[0014] The silane coupling agent is one of γ-aminopropyl triethoxysilane and γ-glycidyloxypropyl trimethoxysilane; the antioxidant is obtained by compounding tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester and dilauryl thiodipropionate in a mass ratio of 2:1; the phosphite is one of tris(2,4-di-tert-butylphenyl) phosphite or tetrakis(2,4-di-tert-butylphenyl) biphenyl bisphosphite; the organic phosphate nucleating agent is sodium phenyl phosphinate; the fatty acid ester lubricant is obtained by mixing stearic acid monoglyceride and ethylene bisstearamide in a mass ratio of 5:3; the ultraviolet absorber is 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol; and the hindered amine light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0015] The polybutylene terephthalate is prepared by the above preparation method.

[0016] The polybutylene terephthalate is used for the production of intelligent driving sensor housings.

[0017] The method for preparing the intelligent driving sensor housing comprises the following steps: A. Add 100 parts of PBT granules to a high-speed mixer, preheat to 60°C, and stir for 5 minutes; B. Add 1.5-2.25 parts of maleic anhydride grafted polypropylene, 0.5-0.75 parts of zinc stearate, 1-2 parts of modified MoS 2 , 1-3 parts of polypyrrole dispersion, 0.3-0.5 parts of antioxidant 1010, stirring continuously for 10 minutes; C. Add it to a twin-screw machine for extrusion, set the temperature of each section of the extruder to 225-250℃, then place it in a mold, the barrel temperature is 240-250℃, the mold temperature is 70-80℃, the injection pressure is 90-110MPa, the holding pressure is 60-70MPa, hold the pressure for 15-20s, and cool for 30-40s, then it can be used for the intelligent driving sensor housing.

[0018] When preparing the housing of the intelligent driving sensor, some raw materials need to be pre-processed: Modified MoS 2 :MoS 2 The nanosheets were dispersed in an oil-in-water emulsion containing 5% silane coupling agent (KH-570), ultrasonically treated for 4 h (frequency 40 kHz, power 300 W), and spray dried (inlet temperature 150 °C, outlet temperature 80 °C) to obtain modified MoS with a surface grafting rate ≥ 90%. 2 (Particle size distribution 5-15nm).

[0019] Polypyrrole (PPy): PPy and carbon nanotubes were ball-milled in a 1:1 ratio in a ball mill (speed 500 r / min, time 2 h) to form a "CNT-PPy" core-shell structure; a 20% slurry was prepared with anhydrous ethanol, and ultrasonic dispersion was performed to form a uniform slurry.

[0020] Titanium-germanium catalyst (compound A) and yttrium-cerium-tetrabutyl titanate (compound B) work synergistically. The former improves the esterification / polycondensation efficiency (reaction time is shortened by 20%), reduces the incidence of side reactions, and ensures the regularity of the polymer chain through titanium-germanium synergistic catalysis; the latter activates erucic acid carboxyl groups through rare earth metal sites, promotes hydrophobic grafting reactions, and the grafting rate reaches more than 85%. Carbon nanotubes (1D conductive pathways), zinc oxide (3D supporting structure) and graphene (2D sheets) form a multi-dimensional synergistic network. Carbon nanotubes provide efficient electron transmission channels, zinc oxide inhibits filler agglomeration, and graphene enhances network continuity, reducing the volume resistivity by 2-3 orders of magnitude (as low as 10²-10³Ω·cm) compared to traditional modified PBT. Tetrabutyl titanate provides Lewis acid sites to accelerate the esterification reaction; germanium ions (Ge 4+ ) Stabilize intermediates through electron transfer and reduce side reactions. Titanium-germanium complexes form highly dispersed active centers on porous silica supports, improving polycondensation efficiency. The long alkyl chains of erucic acid bind to the organic layer of silanized ZnO through hydrophobic interactions, reducing interface defects.

[0021] Although zinc oxide (ZnO) is an insulator, after being treated with a silane coupling agent, an organic functional layer (such as amino or epoxy) is formed on the surface, which is combined with carbon nanotubes (CNTs) through chemical bonds or physical adsorption. ZnO nanoparticles (particle size 5-15nm) act as "spacers" to prevent CNT agglomeration and promote the formation of a three-dimensional conductive network. At the same time, the semiconductor properties of ZnO can form a microcapacitor effect at the interface, enhancing local conductivity.

[0022] Dicumyl peroxide (DCP) induces crosslinking of PBT molecular chains, increasing the crystallinity by 15%, the heat deformation temperature by 160-180°C, and the creep resistance by 15%. The carboxylic acid group of maleic anhydride grafted polypropylene (MAPP) reacts with the ester bond of PBT to form a covalent bond, and the modified molybdenum disulfide (MoS 2 ) and carbon nanotubes, significantly enhancing the filler-matrix interface bonding, reducing interface defects, and increasing tensile strength by 25%. Zinc stearate (ZnSt) forms a lubricating film in the molten state, reducing molecular chain friction (melt viscosity decreases by 15%) and improving processing fluidity; the "pre-dispersion-post-enhancement" dual-stage synergy of MAPP and premixed conductive fillers in the injection molding stage ensures the consistency of the conductive performance of the final product (resistivity fluctuation ≤±8%).

[0023] The long chain alkyl group (C 18 H 35- ) migrate to the material surface during processing to form a low surface energy layer; modified MoS 2The lamellar structure is dispersed in the PBT matrix in an exfoliated state. The sulfur atom surface is entangled with the ZnSt alkyl chain through van der Waals force, which hinders the penetration path of water molecules. Polypyrrole, as a conductive polymer, wraps carbon nanotubes and MoS 2 surface, forming "CNT-PPy-MoS 2 "The conductive network reduces filler agglomeration; the high modulus and lamellar structure of the nanosheets hinder crack propagation and improve tensile strength.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) The polybutylene terephthalate prepared by the present invention has a volume resistivity as low as 10²-10³Ω·cm, which meets the electromagnetic shielding requirements of the intelligent driving sensor housing (≥40dB). The crosslinking agent (DCP) and the nucleating agent (sodium phenylphosphinate) improve the crystallinity, the tensile strength reaches 60-65MPa, and the impact strength is ≥13kJ / m², which is suitable for the vehicle vibration environment.

[0025] (2) The polybutylene terephthalate prepared by the present invention has a heat deformation temperature increased to 160-180°C and can withstand a high temperature of 150°C for a long time. Zinc stearate optimizes melt fluidity, and the surface finish Ra is ≤1.2μm. After aging at 85°C / 85%RH for 1000h, the performance fluctuation is <5%, and there is no hydrolysis cracking.

[0026] (3) The present invention achieves a comprehensive improvement in the electrical conductivity, mechanical strength, heat resistance and processing performance of PBT materials through composite catalysis, multi-dimensional conductive network design and dynamic cross-linking modification. DETAILED DESCRIPTION

[0027] In order to make the purpose and technical solution of the present invention more clear, the present invention is further described in detail below.

[0028] Test method: Volume resistivity: ASTM D257 "Standard Test Method for DC Resistance or Conductivity of Insulating Materials"; Electromagnetic shielding effectiveness (SE): ASTM D4935 "Test method for electromagnetic shielding effectiveness of planar materials"; Tensile strength: ISO 527-2 "Determination of tensile properties of plastics Part 2: Test conditions for moulding and extruded plastics"; Flexural strength: ISO 178 "Determination of flexural properties of plastics"; Impact strength (notched): ISO 179-1 "Determination of impact properties of simply supported beams of plastics - Part 1: Non-instrumented impact test"; Heat Deflection Temperature (HDT): ISO 75-2 "Plastics - Determination of Deflection Temperature under Load - Part 2: Plastics and Hard Rubber"; Water absorption: ISO 62 "Determination of water absorption of plastics"; Surface finish (Ra): ISO 4287 "Geometric Product Specification (GPS) Surface structure: Profile method terms, definitions and surface structure parameters".

[0029] Example 1 The preparation method of the composite catalyst A comprises the following steps: ① Dissolve 10g of hexadecyltrimethylammonium bromide in deionized water and stir at 40°C until completely dissolved; add ammonia water to adjust the pH value to 9, then add 40ml of ethyl orthosilicate dropwise, and continue stirring to react for 2h; filter and wash the reaction product, and then dry it at 110°C for 18h; finally calcine at 500°C for 4h to obtain a porous silica carrier; ② Take materials according to the molar ratio of titanium to germanium of 3:1, dissolve tetrabutyl titanate in anhydrous ethanol to form a titanium solution; put germanium dioxide in a container, add 30% concentrated hydrochloric acid and heat to 50°C to dissolve it to form a germanium solution; under stirring, add the germanium solution dropwise to the titanium solution, continue stirring for 1 hour, and obtain a titanium-germanium composite solution; ③ Take the material according to the lithium: titanium molar ratio of 0.01:1, dissolve it in deionized water to prepare a lithium solution; ④ Premix the lithium solution and the titanium-germanium composite solution to obtain a mixed solution; add the porous silica carrier to the mixed solution and stir at room temperature for 6 hours; remove the solvent by vacuum distillation to obtain a solid product; dry the solid product at 105°C for 15 hours, and then calcine at 300°C for 2 hours to obtain a composite catalyst A.

[0030] The surface treatment method of carbon nanotubes is as follows: placing carbon nanotubes in a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, adding 20 ml of the mixed acid per gram of carbon nanotubes, ultrasonically treating at 40° C. for 2 hours, and then washing with deionized water until neutral.

[0031] The modification method of zinc oxide comprises the following steps: a. Add silane and solvent to an ethanol / water mixture at a ratio of 1 wt%, add glacial acetic acid dropwise to adjust the pH to 4, and stir magnetically for 30 min; b. Dry the zinc oxide powder at 100°C for 2h; c. The dried zinc oxide was added to the mixture obtained in step a at a mass ratio of 1:10 and ultrasonically treated at 40 ° C for 3 h; d. The mixture obtained in step c was centrifuged, the supernatant was removed, the precipitate was washed three times with anhydrous ethanol, and the washed ZnO was vacuum dried at 80°C for 12h to obtain silanized zinc oxide.

[0032] The preparation method of the composite catalyst B comprises the following steps: Ⅰ. After calcining yttrium oxide and cerium oxide at 500℃ for 1h, add them into anhydrous ethanol and perform ultrasonic dispersion for 30min; Ⅱ. Tetrabutyl titanate was added to a container, and then the product obtained in step Ⅰ was added to the container containing tetrabutyl titanate, and the mixture was stirred while pouring at a stirring speed of 300 r / min for 1 h to obtain a composite catalyst precursor solution; III. The composite catalyst precursor solution was sealed and aged at room temperature for 20 hours. The total mass concentration of tetrabutyl titanate, yttrium oxide and cerium oxide in the aged solution was 10%, and composite catalyst B was obtained.

[0033] The mass ratio of tetrabutyl titanate, yttrium oxide and cerium oxide is 1:0.1:0.5; the active ingredients of the composite catalyst B are tetrabutyl titanate, yttrium oxide and cerium oxide, and the amount of the active ingredients added is 0.05% of the total mass of the reactants in step (3).

[0034] The preparation method of polybutylene terephthalate comprises the following steps: (1) Add terephthalic acid and 1,4-butanediol into a reactor at a molar ratio of 1:1.2, add composite catalyst A, heat to 210°C, carry out esterification reaction, react for 4 hours, then heat to 240°C, carry out polycondensation reaction, react for 6 hours, and obtain polybutylene terephthalate base polymer; (2) blending an antioxidant with a polybutylene terephthalate base polymer in a twin-screw extruder to obtain an intermediate, then mixing the surface-treated carbon nanotubes and the modified zinc oxide in a mass ratio of 1:1, and blending them with the intermediate in a twin-screw extruder, wherein the temperature of each section of the extruder is set to 230° C. and the screw speed is 200 r / min, thereby obtaining a polybutylene terephthalate base polymer having conductivity; (3) adding the product obtained in step (2) and erucic acid in a mass ratio of 10:1 into a reaction kettle, then adding the composite catalyst B and phosphite, introducing nitrogen protection, heating to 190° C. under stirring, reacting for 4 h, then washing and drying the product to obtain a hydrophobic polybutylene terephthalate base polymer; (4) The product obtained in step (3), maleic anhydride, an organic phosphate nucleating agent, a fatty acid ester lubricant, an ultraviolet absorber and a hindered amine light stabilizer are added to a twin-screw extruder for blending, and the temperature of each section of the extruder is set to 230° C. to obtain polybutylene terephthalate.

[0035] The amount of the composite catalyst A added is 0.2% of the total mass of the reactants in step (1); the total amount of the carbon nanotubes and zinc oxide added in step (2) is 3% of the total mass of the reactants in step (2); the amount of the phosphite added is 0.1% of the total mass of the reactants in step (3); the amount of the antioxidant added is 0.3% of the mass of the polybutylene terephthalate base polymer in step (2); the amount of maleic anhydride added is 1% of the mass of the product obtained in step (3); the amount of the organic phosphate nucleating agent added is 0.5% of the mass of the product obtained in step (3); the amount of the fatty acid ester lubricant added is 0.3% of the mass of the product obtained in step (3); the amount of the ultraviolet absorber added is 0.5% of the mass of the product obtained in step (3); and the amount of the hindered amine light stabilizer added is 0.5% of the mass of the product obtained in step (3).

[0036] The silane coupling agent is γ-aminopropyltriethoxysilane; the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and dilauryl thiodipropionate in a mass ratio of 2:1; the phosphite is tris(2,4-di-tert-butylphenyl)phosphite; the organic phosphate nucleating agent is sodium phenylphosphinate; the fatty acid ester lubricant is a mixture of stearic acid monoglyceride and ethylene bisstearamide in a mass ratio of 5:3; the ultraviolet absorber is 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol; and the hindered amine light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0037] Example 2 The preparation method of the composite catalyst A comprises the following steps: ① Dissolve 10g of hexadecyltrimethylammonium bromide in deionized water and stir at 50°C until completely dissolved; add ammonia water to adjust the pH value to 10, then add 50ml of ethyl orthosilicate dropwise, and continue stirring to react for 4h; filter and wash the reaction product, and then dry it at 110°C for 18h; finally calcine at 550°C for 5h to obtain a porous silica carrier; ② Take materials according to the molar ratio of titanium to germanium of 5:1, dissolve tetrabutyl titanate in anhydrous ethanol to form a titanium solution; put germanium dioxide in a container, add 34% concentrated hydrochloric acid and heat to 65°C to dissolve it to form a germanium solution; under stirring, add the germanium solution dropwise to the titanium solution, continue stirring for 2 hours, and obtain a titanium-germanium composite solution; ③ Take the material according to the lithium: titanium molar ratio of 0.05:1, dissolve it in deionized water to prepare a lithium solution; ④ Premix the lithium solution and the titanium-germanium composite solution to obtain a mixed solution; add the porous silica carrier to the mixed solution and stir at room temperature for 9 hours; remove the solvent by vacuum distillation to obtain a solid product; dry the solid product at 108°C for 18 hours, and then calcine at 400°C for 3 hours to obtain a composite catalyst A.

[0038] The surface treatment method of carbon nanotubes is as follows: placing carbon nanotubes in a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, using 15 ml of the mixed acid per gram of carbon nanotubes, ultrasonically treating at 45° C. for 3 hours, and then washing with deionized water until neutral.

[0039] The modification method of zinc oxide comprises the following steps: a. Add silane and solvent to an ethanol / water mixture at a ratio of 2 wt%, add glacial acetic acid dropwise to adjust the pH to 4, and stir magnetically for 45 min; b. Dry the zinc oxide powder at 110°C for 3h; c. The dried zinc oxide was added to the mixture obtained in step a at a mass ratio of 1:15 and ultrasonically treated at 45 ° C for 3 h; d. The mixture obtained in step c was centrifuged, the supernatant was removed, the precipitate was washed 4 times with anhydrous ethanol, and the washed ZnO was vacuum dried at 90°C for 10h to obtain silanized zinc oxide.

[0040] The preparation method of the composite catalyst B comprises the following steps: Ⅰ. After calcining yttrium oxide and cerium oxide at 600℃ for 2h, they were added into anhydrous ethanol and ultrasonically dispersed for 40min; Ⅱ. Tetrabutyl titanate was added to a container, and then the product obtained in step Ⅰ was added to the container containing tetrabutyl titanate, and the mixture was stirred while pouring at a stirring speed of 300 r / min for 1 h to obtain a composite catalyst precursor solution; III. The composite catalyst precursor solution was sealed and aged at room temperature for 24 hours. The total mass concentration of tetrabutyl titanate, yttrium oxide and cerium oxide in the aged solution was 15%, and composite catalyst B was obtained.

[0041] The mass ratio of tetrabutyl titanate, yttrium oxide and cerium oxide is 1:0.5:0.5; the active ingredients of the composite catalyst B are tetrabutyl titanate, yttrium oxide and cerium oxide, and the amount of the active ingredients added is 0.1% of the total mass of the reactants in step (3).

[0042] The preparation method of polybutylene terephthalate comprises the following steps: (1) Add terephthalic acid and 1,4-butanediol into a reactor at a molar ratio of 1:1.2, add composite catalyst A, heat to 220°C, carry out esterification reaction, react for 3 hours, then heat to 250°C, carry out polycondensation reaction, react for 4 hours, and obtain polybutylene terephthalate base polymer; (2) blending an antioxidant with a polybutylene terephthalate base polymer in a twin-screw extruder to obtain an intermediate, then mixing the surface-treated carbon nanotubes and the modified zinc oxide in a mass ratio of 2:1, and blending them with the intermediate in a twin-screw extruder, wherein the temperature of each section of the extruder is set to 240° C. and the screw speed is 300 r / min, thereby obtaining a polybutylene terephthalate base polymer having conductivity; (3) adding the product obtained in step (2) and erucic acid in a mass ratio of 10:1 into a reaction kettle, then adding the composite catalyst B and phosphite, introducing nitrogen protection, heating to 200° C. under stirring, reacting for 4 h, then washing and drying the product to obtain a hydrophobic polybutylene terephthalate base polymer; (4) The product obtained in step (3), maleic anhydride, an organic phosphate nucleating agent, a fatty acid ester lubricant, an ultraviolet absorber and a hindered amine light stabilizer are added to a twin-screw extruder for blending, and the temperature of each section of the extruder is set to 240° C. to obtain polybutylene terephthalate.

[0043] The amount of the composite catalyst A added is 0.3% of the total mass of the reactants in step (1); the total amount of the carbon nanotubes and zinc oxide added in step (2) is 5% of the total mass of the reactants in step (2); the amount of the phosphite added is 0.2% of the total mass of the reactants in step (3); the amount of the antioxidant added is 0.8% of the mass of the polybutylene terephthalate base polymer in step (2); the amount of maleic anhydride added is 2% of the mass of the product obtained in step (3); the amount of the organic phosphate nucleating agent added is 1.2% of the mass of the product obtained in step (3); the amount of the fatty acid ester lubricant added is 0.6% of the mass of the product obtained in step (3); the amount of the ultraviolet absorber added is 0.8% of the mass of the product obtained in step (3); and the amount of the hindered amine light stabilizer added is 0.7% of the mass of the product obtained in step (3).

[0044] The silane coupling agent is γ-glycidyloxypropyltrimethoxysilane; the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and dilauryl thiodipropionate in a mass ratio of 2:1; the phosphite is tetrakis(2,4-di-tert-butylphenyl)biphenyl diphosphite; the organic phosphate nucleating agent is sodium phenylphosphinate; the fatty acid ester lubricant is a mixture of stearic acid monoglyceride and ethylene bisstearamide in a mass ratio of 5:3; the ultraviolet absorber is 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol; and the hindered amine light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate.

[0045] Example 3 The preparation method of the composite catalyst A comprises the following steps: ① Dissolve 10g of hexadecyltrimethylammonium bromide in deionized water and stir at 60°C until completely dissolved; add ammonia water to adjust the pH value to 11, then add 60ml of ethyl orthosilicate dropwise, and continue stirring to react for 6 hours; filter and wash the reaction product, and then dry it at 110°C for 18 hours; finally calcine at 600°C for 4 hours to obtain a porous silica carrier; ② Take materials according to the molar ratio of titanium to germanium of 8:1, dissolve tetrabutyl titanate in anhydrous ethanol to form a titanium solution; put germanium dioxide in a container, add 37% concentrated hydrochloric acid and heat to 80°C to dissolve it to form a germanium solution; under stirring, add the germanium solution dropwise to the titanium solution, continue stirring for 3 hours, and obtain a titanium-germanium composite solution; ③ Take the material according to the lithium: titanium molar ratio of 0.1:1, dissolve it in deionized water to prepare a lithium solution; ④ Premix the lithium solution and the titanium-germanium composite solution to obtain a mixed solution; add the porous silica carrier to the mixed solution and stir at room temperature for 12 hours; remove the solvent by vacuum distillation to obtain a solid product; dry the solid product at 110°C for 15 hours, and then calcine at 500°C for 2 hours to obtain a composite catalyst A.

[0046] The surface treatment method of carbon nanotubes is as follows: placing carbon nanotubes in a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, using 10 ml of the mixed acid per gram of carbon nanotubes, ultrasonically treating at 50° C. for 2 hours, and then washing with deionized water until neutral.

[0047] The modification method of zinc oxide comprises the following steps: a. Add silane: solvent to ethanol / water mixture at a ratio of 3wt%, add glacial acetic acid dropwise to adjust pH to 5, and stir magnetically for 60min; b. Dry the zinc oxide powder at 120°C for 4 hours; c. The dried zinc oxide was added to the mixture obtained in step a at a mass ratio of 1:20 and ultrasonically treated at 50 ° C for 2 h; d. The mixture obtained in step c was centrifuged, the supernatant was removed, and the precipitate was washed 5 times with anhydrous ethanol. The washed ZnO was vacuum dried at 100 ° C for 6 h to obtain silanized zinc oxide.

[0048] The preparation method of the composite catalyst B comprises the following steps: Ⅰ. After calcining yttrium oxide and cerium oxide at 700℃ for 1h, they were added into anhydrous ethanol and ultrasonically dispersed for 45min; Ⅱ. Tetrabutyl titanate was added to a container, and then the product obtained in step Ⅰ was added to a container containing tetrabutyl titanate, and the mixture was stirred while pouring at a stirring speed of 300 r / min for 1.5 h to obtain a composite catalyst precursor solution; III. The composite catalyst precursor solution was sealed and aged at room temperature for 24 hours. The total mass concentration of tetrabutyl titanate, yttrium oxide and cerium oxide in the aged solution was 20%, and composite catalyst B was obtained.

[0049] The mass ratio of tetrabutyl titanate, yttrium oxide and cerium oxide is 1:1:0.5; the active ingredients of the composite catalyst B are tetrabutyl titanate, yttrium oxide and cerium oxide, and the amount of the active ingredients added is 0.2% of the total mass of the reactants in step (3).

[0050] The preparation method of polybutylene terephthalate comprises the following steps: (1) Add terephthalic acid and 1,4-butanediol into a reactor at a molar ratio of 1:1.2, add composite catalyst A, heat to 230°C, carry out esterification reaction, react for 2 hours, then heat to 260°C, carry out polycondensation reaction, react for 3 hours, and obtain polybutylene terephthalate base polymer; (2) blending an antioxidant with a polybutylene terephthalate base polymer in a twin-screw extruder to obtain an intermediate, then mixing the surface-treated carbon nanotubes and the modified zinc oxide in a mass ratio of 3:1, and blending them with the intermediate in a twin-screw extruder, wherein the temperature of each section of the extruder is set to 250° C. and the screw speed is 400 r / min, thereby obtaining a polybutylene terephthalate base polymer having conductivity; (3) adding the product obtained in step (2) and erucic acid in a mass ratio of 10:1 into a reaction kettle, then adding the composite catalyst B and phosphite, introducing nitrogen protection, heating to 210° C. under stirring, reacting for 4.5 hours, then washing and drying the product to obtain a hydrophobic polybutylene terephthalate base polymer; (4) The product obtained in step (3), maleic anhydride, an organic phosphate nucleating agent, a fatty acid ester lubricant, an ultraviolet absorber and a hindered amine light stabilizer are added to a twin-screw extruder for blending, and the temperature of each section of the extruder is set to 250° C. to obtain polybutylene terephthalate.

[0051] The amount of the composite catalyst A added is 0.5% of the total mass of the reactants in step (1); the total amount of the carbon nanotubes and zinc oxide added in step (2) is 7% of the total mass of the reactants in step (2); the amount of the phosphite added is 0.3% of the total mass of the reactants in step (3); the amount of the antioxidant added is 1% of the mass of the polybutylene terephthalate base polymer in step (2); the amount of maleic anhydride added is 3% of the mass of the product obtained in step (3); the amount of the organic phosphate nucleating agent added is 2% of the mass of the product obtained in step (3); the amount of the fatty acid ester lubricant added is 1% of the mass of the product obtained in step (3); the amount of the ultraviolet absorber added is 1% of the mass of the product obtained in step (3); and the amount of the hindered amine light stabilizer added is 1% of the mass of the product obtained in step (3).

[0052] The silane coupling agent is γ-aminopropyltriethoxysilane; the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and dilauryl thiodipropionate in a mass ratio of 2:1; the phosphite is tris(2,4-di-tert-butylphenyl)phosphite; the organic phosphate nucleating agent is sodium phenylphosphinate; the fatty acid ester lubricant is a mixture of stearic acid monoglyceride and ethylene bisstearamide in a mass ratio of 5:3; the ultraviolet absorber is 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol; and the hindered amine light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0053] Comparative Example 1 Compared with Example 1, the difference is that tetrabutyl titanate is used as catalyst A, and the added amount is 0.2% of the total mass of the reactants in step (1).

[0054] Comparative Example 2 Compared with Example 1, the difference is that the carbon nanotubes are directly mixed with zinc oxide without being treated with mixed acid.

[0055] Comparative Example 3 Compared with Example 1, the difference is that erucic acid grafting and phosphite addition are not performed.

[0056] Comparative Example 4 Compared with Example 1, the difference is that only carbon nanotubes are added, and the added amount is 7% of the total mass of the reactants in step (2).

[0057] The test data of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1.

[0058] Table 1: Test data of Examples 1-3 and Comparative Examples 1-4

[0059] It can be seen from Table 1 that the resistivity (10 4 Ω·cm) is much higher than that of the examples (10²-10³Ω·cm), indicating that the composite catalyst A (titanium-germanium) significantly improves the polycondensation efficiency and conductivity. The conductivity of the comparative example 2 (untreated carbon nanotubes) (2.7×10 5 Ω·cm) is lower than Example 1 (1.2×10³Ω·cm), and the mixed acid treatment effectively removes impurities and enhances dispersibility. The water absorption rate of Comparative Example 3 (without erucic acid grafting) is as high as 1.8%, while the water absorption rate of the example is only 0.2-0.3%, and erucic acid grafting significantly improves hydrophobicity. The electromagnetic shielding effectiveness (28dB) of Comparative Example 4 (only carbon nanotubes) is lower than that of the example (35-45dB), and the synergistic effect of zinc oxide and graphene strengthens the conductive network.

[0060] Application Example 1 Modified MoS 2 :MoS 2 The nanosheets were dispersed in an oil-in-water emulsion containing 5% KH-570, and ultrasonically treated for 4 h (frequency 40 kHz, power 300 W); spray dried (inlet temperature 150 °C, outlet temperature 80 °C) to obtain modified MoS with a surface grafting rate ≥ 90%. 2 (Particle size distribution 10nm).

[0061] Polypyrrole (PPy): PPy and carbon nanotubes were ball-milled in a 1:1 ratio in a ball mill (speed 500 r / min, time 2 h) to form a "CNT-PPy" core-shell structure; a 20% slurry was prepared with anhydrous ethanol, and ultrasonic dispersion was performed to form a uniform slurry.

[0062] A method for preparing a housing of an intelligent driving sensor comprises the following steps: A. Add 100 parts of the product obtained in Example 2 into a high-speed mixer, preheat to 60°C, and stir for 5 minutes; B. Add 2.25 parts of maleic anhydride grafted polypropylene, 0.75 parts of zinc stearate, 2 parts of modified MoS 2 , 3 parts of polypyrrole dispersion, 0.5 parts of antioxidant 1010, stirring continuously for 10 minutes; C. Add it to a twin-screw machine for extrusion, set the temperature of each section of the extruder to 250°C, then place it in a mold, set the barrel temperature to 250°C, the mold temperature to 80°C, the injection pressure to 110MPa, the holding pressure to 70MPa, hold the pressure for 20s, and cool for 40s, and it can be used for the intelligent driving sensor housing.

[0063] Application Example 2 Modified MoS 2 :MoS 2 The nanosheets were dispersed in an oil-in-water emulsion containing 5% KH-570, and ultrasonically treated for 4 h (frequency 40 kHz, power 300 W); spray dried (inlet temperature 150 °C, outlet temperature 80 °C) to obtain modified MoS with a surface grafting rate ≥ 90%. 2 (Particle size distribution 15nm).

[0064] Polypyrrole (PPy): PPy and carbon nanotubes were ball-milled in a 1:1 ratio in a ball mill (speed 500 r / min, time 2 h) to form a "CNT-PPy" core-shell structure; a 20% slurry was prepared with anhydrous ethanol, and ultrasonic dispersion was performed to form a uniform slurry.

[0065] A method for preparing a housing of an intelligent driving sensor comprises the following steps: A. Add 100 parts of the product obtained in Example 1 into a high-speed mixer, preheat to 60°C, and stir for 5 minutes; B. Add 1.5 parts of maleic anhydride grafted polypropylene, 0.5 parts of zinc stearate, 1 part of modified MoS 2 , 1 part of polypyrrole dispersion, 0.3 part of antioxidant 1010, stirring continuously for 10 minutes; C. Add it to a twin-screw machine for extrusion, set the temperature of each section of the extruder to 225°C, then place it in a mold, set the barrel temperature to 240°C, the mold temperature to 70°C, the injection pressure to 90MPa, the holding pressure to 60MPa, hold the pressure for 15s, and cool for 30s, and it can be used for the intelligent driving sensor housing.

[0066] Application Example 3 Modified MoS 2 :MoS 2 The nanosheets were dispersed in an oil-in-water emulsion containing 5% KH-570, and ultrasonically treated for 4 h (frequency 40 kHz, power 300 W); spray dried (inlet temperature 150 °C, outlet temperature 80 °C) to obtain modified MoS with a surface grafting rate ≥ 90%. 2 (Particle size distribution 5nm).

[0067] Polypyrrole (PPy): PPy and carbon nanotubes were ball-milled in a 1:1 ratio in a ball mill (speed 500 r / min, time 2 h) to form a "CNT-PPy" core-shell structure; a 20% slurry was prepared with anhydrous ethanol, and ultrasonic dispersion was performed to form a uniform slurry.

[0068] A method for preparing a housing of an intelligent driving sensor comprises the following steps: A. Add 100 parts of the product obtained in Example 3 into a high-speed mixer, preheat to 60°C, and stir for 5 minutes; B. Add 2 parts of maleic anhydride grafted polypropylene, 0.6 parts of zinc stearate, 2 parts of modified MoS 2 , 3 parts of polypyrrole dispersion, 0.3 parts of antioxidant 1010, stirring continuously for 10 minutes; C. Add it to a twin-screw machine for extrusion, set the temperature of each section of the extruder to 240°C, then place it in a mold, set the barrel temperature to 245°C, the mold temperature to 75°C, the injection pressure to 100MPa, the holding pressure to 65MPa, hold the pressure for 18s, and cool for 35s, and it can be used for the intelligent driving sensor housing.

[0069] Application Comparative Example 1 Compared with Application Example 1, the difference is that maleic anhydride grafted polypropylene is not added.

[0070] Application Comparative Example 2 Compared with Application Example 2, the difference is that no modified MoS 2 .

[0071] Application Comparative Example 3 Compared with Application Example 3, the difference is that zinc stearate is not added.

[0072] The test data of application examples 1-3 and application comparative examples 1-3 are shown in Table 2.

[0073] Table 2: Test data of application examples 1-3 and application comparative examples 1-3

[0074] It can be seen from Table 2 that the conductivity of Comparative Example 1 (1.2×10 4 Ω·cm) decreased significantly, due to insufficient interface bonding leading to filler agglomeration. The impact strength of comparative example 2 (11.5 kJ / m²) was lower than that of the example (13-14.5 kJ / m²), indicating that MoS 2 The layered structure improves toughness and dispersibility. The surface finish of the comparative example 3 (3.0 μm) is much higher than that of the example (0.8-1.2 μm), which shows that zinc stearate is used to optimize melt fluidity and reduce processing defects.

[0075] The present invention achieves a comprehensive improvement in the conductivity, mechanical strength, heat resistance and processing performance of PBT materials through composite catalysis, multi-dimensional conductive network design and dynamic cross-linking modification. The application example data verifies that maleic anhydride grafted polypropylene, modified MoS 2 It plays a key role in meeting the high-standard requirements of intelligent driving sensor housings and has significant industrialization potential.

Claims

1. A method for preparing polybutylene terephthalate, characterized in that: The following steps are involved: (1) Add terephthalic acid and 1,4-butanediol into a reactor at a molar ratio of 1:1.2, add composite catalyst A, raise the temperature to 210-230°C, carry out esterification reaction, react for 2-4 hours, then raise the temperature to 240-260°C, carry out polycondensation reaction, react for 3-6 hours, and obtain polybutylene terephthalate base polymer; (2) blending an antioxidant with a polybutylene terephthalate base polymer in a twin-screw extruder to obtain an intermediate, then mixing the surface-treated carbon nanotubes and the modified zinc oxide in a mass ratio of (1-3):1, and blending them with the intermediate in a twin-screw extruder, wherein the temperature of each section of the extruder is set to 230-250° C. and the screw speed is 200-400 r / min to obtain a polybutylene terephthalate base polymer having conductivity; (3) adding the product obtained in step (2) and erucic acid in a mass ratio of 10:1 into a reaction kettle, then adding the composite catalyst B and phosphite, introducing nitrogen protection, heating to 190-210° C. under stirring, reacting for 4-4.5 hours, then washing and drying the product to obtain a hydrophobic polybutylene terephthalate base polymer; (4) adding the product obtained in step (3), maleic anhydride, an organic phosphate nucleating agent, a fatty acid ester lubricant, an ultraviolet absorber and a hindered amine light stabilizer into a twin-screw extruder for blending, and setting the temperature of each section of the extruder to 230-250° C. to obtain polybutylene terephthalate; The compound catalyst A is a titanium-germanium compound catalyst; the compound catalyst B is a yttrium-cerium-tetrabutyl titanate compound catalyst.

2. The method for preparing polybutylene terephthalate according to claim 1, characterized in that: The amount of the composite catalyst A added is 0.2-0.5% of the total mass of the reactants in step (1); the total amount of the carbon nanotubes and zinc oxide added in step (2) is 3-7% of the total mass of the reactants in step (2); the amount of the phosphite added is 0.1-0.3% of the total mass of the reactants in step (3); the amount of the antioxidant added is 0.3-1% of the mass of the polybutylene terephthalate base polymer in step (2); the amount of maleic anhydride added is 1-3% of the mass of the product obtained in step (3); the amount of the organic phosphate nucleating agent added is 0.5-2% of the mass of the product obtained in step (3); the amount of the fatty acid ester lubricant added is 0.3-1% of the mass of the product obtained in step (3); the amount of the ultraviolet absorber added is 0.5-1% of the mass of the product obtained in step (3); and the amount of the hindered amine light stabilizer added is 0.5-1% of the mass of the product obtained in step (3).

3. The method for preparing polybutylene terephthalate according to claim 1, characterized in that: The preparation method of the composite catalyst A comprises the following steps: ① Dissolve 10g of hexadecyltrimethylammonium bromide in deionized water and stir at 40-60°C until dissolved; add ammonia water to adjust the pH value to 9-11, then add 40-60ml of ethyl orthosilicate dropwise, and continue stirring to react for 2-6h; filter and wash the reaction product, and then dry it at 110°C for 18h; finally calcine at 500-600°C for 4-6h to obtain a porous silica carrier; ② Take materials according to the molar ratio of titanium to germanium (3-8):1, dissolve tetrabutyl titanate in anhydrous ethanol to form a titanium solution; put germanium dioxide in a container, add 30-37% concentrated hydrochloric acid and heat to 50-80°C to dissolve, forming a germanium solution; under stirring, add the germanium solution dropwise to the titanium solution, continue stirring for 1-3 hours, and obtain a titanium-germanium composite solution; ③ Take the material according to the lithium: titanium molar ratio (0.01-0.1):1, dissolve it in deionized water to prepare a lithium solution; ④ Premix the lithium solution and the titanium-germanium composite solution to obtain a mixed solution; add the porous silica carrier to the mixed solution and stir at room temperature for 6-12 hours; distill under reduced pressure to remove the solvent to obtain a solid product; dry the solid product at 105-110° C. for 15-20 hours, and then calcine at 300-500° C. for 2-4 hours to obtain a composite catalyst A.

4. The method for preparing polybutylene terephthalate according to claim 1, characterized in that: The surface treatment method of the carbon nanotubes is as follows: placing the carbon nanotubes in a mixed acid with a volume ratio of concentrated sulfuric acid to concentrated nitric acid of 3:1, ultrasonically treating the carbon nanotubes at 40-50°C for 2-3 hours, and then washing with deionized water until neutral; the modification method of zinc oxide is as follows: adding a silane coupling agent to an ethanol / water mixture, then adding zinc oxide powder, ultrasonically treating, centrifuging and drying, to obtain silanized zinc oxide.

5. The method for preparing polybutylene terephthalate according to claim 1, characterized in that: The preparation method of the composite catalyst B comprises the following steps: Ⅰ. After calcining yttrium oxide and cerium oxide at 500-700℃ for 1-3h, add them into anhydrous ethanol and perform ultrasonic dispersion for 30-45min; Ⅱ. Tetrabutyl titanate is added to a container, and then the product obtained in step Ⅰ is added to a container containing tetrabutyl titanate, and the mixture is poured while stirring at a stirring speed of 300 r / min for 1-1.5 h to obtain a composite catalyst precursor solution; III. The composite catalyst precursor solution is sealed and aged at room temperature for 20-24 hours. The total mass concentration of tetrabutyl titanate, yttrium oxide and cerium oxide in the aged solution is 10-20%, and the composite catalyst B is obtained.

6. The method for preparing polybutylene terephthalate according to claim 5, characterized in that: The mass ratio of tetrabutyl titanate, yttrium oxide and cerium oxide is 1:(0.1-1):0.5; the active ingredients of the composite catalyst B are tetrabutyl titanate, yttrium oxide and cerium oxide, and the amount of the active ingredients added is 0.05-0.2% of the total mass of the reactants in step (3).

7. The method for preparing polybutylene terephthalate according to claim 4, characterized in that: The silane coupling agent is one of γ-aminopropyl triethoxysilane and γ-glycidyloxypropyl trimethoxysilane; the antioxidant is obtained by compounding tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester and dilauryl thiodipropionate in a mass ratio of 2:1; the phosphite is one of tris(2,4-di-tert-butylphenyl) phosphite or tetrakis(2,4-di-tert-butylphenyl) biphenyl bisphosphite; the organic phosphate nucleating agent is sodium phenyl phosphinate; the fatty acid ester lubricant is obtained by mixing stearic acid monoglyceride and ethylene bisstearamide in a mass ratio of 5:3; the ultraviolet absorber is 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol; and the hindered amine light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

8. A polybutylene terephthalate, characterized in that: The polybutylene terephthalate is prepared by the preparation method of any one of claims 1 to 7.

9. A use of polybutylene terephthalate according to claim 8, characterized in that: Used for the production of smart driving sensor housings.

10. The use of polybutylene terephthalate according to claim 9, characterized in that: The method for preparing the intelligent driving sensor housing comprises the following steps: A. Add 100 parts of polybutylene terephthalate particles into a high-speed mixer, preheat to 60°C, and stir for 5 minutes; B. Add 1.5-2.25 parts of maleic anhydride grafted polypropylene, 0.5-0.75 parts of zinc stearate, 1-2 parts of modified MoS2, 1-3 parts of polypyrrole dispersion, and 0.3-0.5 parts of antioxidant 1010 in sequence, and continue stirring for 10 minutes; C. Add it to a twin-screw machine for extrusion, set the temperature of each section of the extruder to 225-250℃, then place it in a mold, the barrel temperature is 240-250℃, the mold temperature is 70-80℃, the injection pressure is 90-110MPa, the holding pressure is 60-70MPa, hold the pressure for 15-20s, and cool for 30-40s, then it can be used for the intelligent driving sensor housing.

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