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CN-121975043-A - Rare earth synergistic ultra-high molecular weight polyethylene catalyst and preparation method thereof

CN121975043ACN 121975043 ACN121975043 ACN 121975043ACN-121975043-A

Abstract

The application discloses a rare earth synergistic ultra-high molecular weight polyethylene catalyst and a preparation method thereof, and relates to the technical field of polyethylene preparation. The composite internal electron donor system is composed of a magnesium halide carrier, a tetravalent titanium compound active component, a rare earth halide synergistic component and a silane electron donor, wherein the rare earth halide and the tetravalent titanium compound form a double active center, and the rare earth halide and the silane electron donor form the composite internal electron donor system. According to the application, the rare earth halide and the titanium compound form a double active center, the special outer electronic structure of the rare earth element and the bonding capability of the back-up valence electronic orbit generate a synergistic catalytic effect with the titanium active center, so that the activation capability of the catalyst on ethylene monomers is greatly enhanced, the polymerization efficiency is improved by 30% -60% compared with the traditional single-titanium active neutral catalyst, and the catalyst consumption cost in industrial production is effectively reduced.

Inventors

  • LIU FUMING
  • WANG HAILIN
  • GAN CHANGSHU

Assignees

  • 四川锦成化学催化剂有限公司

Dates

Publication Date
20260505
Application Date
20260305

Claims (10)

  1. 1. The rare earth synergistic ultra-high molecular weight polyethylene catalyst is characterized by comprising the following components: The composite internal electron donor system comprises a magnesium halide carrier, a tetravalent titanium compound active component, a rare earth halide synergistic component and a silane electron donor, wherein the rare earth halide and the tetravalent titanium compound form a double active center, and the rare earth halide and the silane electron donor form the composite internal electron donor system.
  2. 2. The rare earth synergistic ultra-high molecular weight polyethylene catalyst according to claim 1, wherein the magnesium halide is any one or a combination of a plurality of magnesium chloride, magnesium bromide and magnesium iodide, and the tetravalent titanium compound is any one or a combination of a plurality of titanium tetrachloride, titanium tetrabromide and titanium tetrabutoxide.
  3. 3. The rare earth synergistic ultra-high molecular weight polyethylene catalyst according to claim 1, wherein the rare earth halide is any one or a combination of more of lanthanum chloride, cerium chloride, neodymium chloride and praseodymium bromide, and the silane electron donor is any one or a combination of more of methylcyclohexyldimethoxy silane, diisopropyl dimethoxy silane and phenyl trimethoxy silane.
  4. 4. The rare earth synergistic ultra-high molecular weight polyethylene catalyst according to claim 1, wherein the molar ratio of rare earth halide to tetravalent titanium compound in the catalyst is 0.1-1.0:1, the molar ratio of the composite internal electron donor to magnesium halide is 0.05-0.5:1, and the weight percentage of active components in the catalyst is 2% -8%.
  5. 5. The preparation method of the rare earth synergistic ultra-high molecular weight polyethylene catalyst is characterized by comprising the following steps of: S1, adding magnesium halide into a mixed system containing an organic alcohol solvent and an inert diluent, heating and stirring until the magnesium halide is completely dissolved to form a homogeneous magnesium salt solution; s2, dropwise adding a tetravalent titanium compound into the homogeneous magnesium salt solution, and stirring and reacting for 1-4 hours at a temperature of-20 ℃ to 10 ℃ to obtain a titanium-magnesium composite solution; S3, adding mixed solution of rare earth halide and silane electron donors into the titanium-magnesium composite solution, heating to 20-60 ℃, and reacting for 2-6 hours at a temperature to obtain reaction slurry; S4, settling and filtering the reaction slurry, and washing the obtained solid for 3-5 times by inert dilution to obtain a solid filter cake; S5, drying the solid filter cake at 60-100 ℃ for 4-12 hours, and activating at 200-400 ℃ for 2-5 hours to obtain the rare earth synergistic ultra-high molecular weight polyethylene catalyst.
  6. 6. The method for preparing the rare earth synergistic ultra-high molecular weight polyethylene catalyst according to claim 5, wherein in the step S1, the organic alcohol solvent is any one or a combination of more of ethanol, propanol and butanol, the inert diluent is any one or a combination of more of n-hexane, n-heptane and cyclohexane, and the volume ratio of the organic alcohol solvent to the inert diluent is 1:5-1:20.
  7. 7. The method for preparing a rare earth synergistic ultra-high molecular weight polyethylene catalyst according to claim 5, wherein the heating temperature in S1 is 40 ℃ to 80 ℃, the stirring speed is 100-500r/min, the dropping rate in S2 is 0.5-5mL/min, the drying in S5 is vacuum drying, and the activation is performed under nitrogen atmosphere.
  8. 8. The method for preparing a rare earth-synergized ultra-high molecular weight polyethylene catalyst according to claim 5, wherein the preparation method satisfies at least one of the following conditions: The molar ratio of the rare earth halide to the tetravalent titanium compound is 0.3-0.7:1, the molar ratio of the composite internal electron donor to the magnesium halide is 0.1-0.3:1, the reaction temperature in S3 is 30-50 ℃, the heat preservation time is 3-5 hours, the drying temperature in S5 is 70-90 ℃, the drying time is 6-10 hours, the activation temperature is 250-350 ℃ and the activation time is 3-4 hours.
  9. 9. A process for the preparation of ultra-high molecular weight polyethylene comprising: The rare earth synergistic ultra-high molecular weight polyethylene catalyst of any one of claims 1 to 4 or the catalyst prepared by the preparation method of any one of claims 5 to 8 is used for ethylene polymerization to obtain ultra-high molecular weight polyethylene.
  10. 10. The method for preparing ultra-high molecular weight polyethylene according to claim 9, wherein the polymerization reaction is slurry polymerization, the polymerization medium is hexane or heptane, the polymerization temperature is 60 ℃ to 90 ℃, the polymerization pressure is 0.5 to 3.0Mpa, the polymerization time is 1 to 6 hours, and the molecular weight of the obtained ultra-high molecular weight polyethylene is 800 ten thousand to 1500 ten thousand.

Description

Rare earth synergistic ultra-high molecular weight polyethylene catalyst and preparation method thereof Technical Field The invention relates to the technical field of polyethylene preparation, in particular to a rare earth synergistic ultra-high molecular weight polyethylene catalyst and a preparation method thereof. Background The ultra-high molecular weight polyethylene has excellent wear resistance, impact resistance, corrosion resistance, self-lubrication and other properties, and is widely applied to high-end fields such as mechanical manufacturing, medical equipment, aerospace, engineering plastics and the like. The catalyst is used as the core for preparing the ultra-high molecular weight polyethylene by ethylene polymerization, and the performance of the catalyst directly determines the polymerization efficiency, the product molecular weight and the structural regularity. The existing ultra-high molecular weight polyethylene catalyst mostly adopts a single titanium compound as an active center, and is provided with a single electron donor of silane type in a multi-collocation way to construct a catalytic system, wherein the catalytic activity of the single titanium active center is limited, so that the ethylene polymerization reaction efficiency is lower, more catalyst dosage is required to be input in industrial production to ensure the yield, the electron regulation effect of the single silane electron donor is insufficient, the stereoselectivity of the catalyst is poor, the molecular chain structure regularity of a polymerization product is required to be improved, and the molecular weight of the ultra-high molecular weight polyethylene prepared by the existing catalyst is limited by the insufficient cooperation of the active center structure and the electron effect, generally only reaches 200 ten thousand to 600 ten thousand, the requirements of the high-end field on higher strength and better wear resistance of materials are difficult to be met, and the application expansion of the ultra-high molecular weight polyethylene in the scenes of extreme working conditions, precise parts and the like is limited. Therefore, the application provides a rare earth synergistic ultra-high molecular weight polyethylene catalyst and a preparation method thereof. Disclosure of Invention The invention aims to provide a rare earth synergistic ultra-high molecular weight polyethylene catalyst and a preparation method thereof, so as to solve the problems in the background technology. In order to achieve the aim, the invention provides the following technical scheme that the rare earth synergistic ultra-high molecular weight polyethylene catalyst consists of the following components: The composite internal electron donor system comprises a magnesium halide carrier, a tetravalent titanium compound active component, a rare earth halide synergistic component and a silane electron donor, wherein the rare earth halide and the tetravalent titanium compound form a double active center, and the rare earth halide and the silane electron donor form the composite internal electron donor system. As a specific scheme in the technical scheme of the application, the magnesium halide is any one or a combination of a plurality of magnesium chloride, magnesium bromide and magnesium iodide, and the tetravalent titanium compound is any one or a combination of a plurality of titanium tetrachloride, titanium tetrabromide and titanium tetrabutoxide. As a specific scheme in the technical scheme of the application, the rare earth halide is any one or a combination of more of lanthanum chloride, cerium chloride, neodymium chloride and praseodymium bromide, and the silane electron donor is any one or a combination of more of methylcyclohexyldimethoxy silane, diisopropyl dimethoxy silane and phenyl trimethoxy silane. As a specific scheme in the technical scheme of the application, in the catalyst, the molar ratio of the rare earth halide to the tetravalent titanium compound is 0.1-1.0:1, the molar ratio of the composite internal electron donor to the magnesium halide is 0.05-0.5:1, and the weight percentage of the active components in the catalyst is 2-8%. The preparation method of the rare earth synergistic ultra-high molecular weight polyethylene catalyst comprises the following steps: S1, adding magnesium halide into a mixed system containing an organic alcohol solvent and an inert diluent, heating and stirring until the magnesium halide is completely dissolved to form a homogeneous magnesium salt solution; s2, dropwise adding a tetravalent titanium compound into the homogeneous magnesium salt solution, and stirring and reacting for 1-4 hours at a temperature of-20 ℃ to 10 ℃ to obtain a titanium-magnesium composite solution; S3, adding mixed solution of rare earth halide and silane electron donors into the titanium-magnesium composite solution, heating to 20-60 ℃, and reacting for 2-6 hours at a temperature to obtain reaction slurry; S4, s