Search

US-12617877-B2 - Metallocene supported catalyst and method for preparing olefine polymer using the same

US12617877B2US 12617877 B2US12617877 B2US 12617877B2US-12617877-B2

Abstract

Provided are a metallocene supported catalyst capable of greatly reducing generation of fine powder during preparation of olefin polymers while exhibiting excellent catalyst activity, and a method of preparing olefin polymers using the same.

Inventors

  • Jinmyung Cha
  • Daesik Hong
  • Sangeun An
  • Seok Hwan Kim

Assignees

  • LG CHEM, LTD.

Dates

Publication Date
20260505
Application Date
20210929
Priority Date
20201016

Claims (13)

  1. 1 . A metallocene supported catalyst comprising: a silica support comprising pores; a transition metal compound supported on the silica support; and nanosilica disposed on a surface of the silica support and has a mean particle size of 10 nm to 100 nm, wherein the mean particle size of the nanosilica is determined by a particle size at a point where a number-based cumulative distribution of particles according to a particle size reaches 50% when a particle size distribution is measured by a laser diffraction analysis, wherein a mean pore size of the pores in the silica support is smaller than the mean particle size of the nanosilica, wherein the transition metal compound is represented by the following Chemical Formula 1: in Chemical Formula 1, A is carbon, silicon, or germanium, X 1 and X 2 are each independently halogen, R 1 and R 2 are each independently C 6-20 aryl unsubstituted or substituted with C 1-20 alkyl, R 2 to R 4 and R 6 to R 8 are each independently hydrogen, halogen, C 1-20 alkyl, C 2-20 alkenyl, C 1-20 alkylsilyl, C 1-20 silylalkyl, C 1-20 alkoxysilyl, C 1-20 ether, C 1-20 silylether, C 1-20 alkoxy, C 6-20 aryl, C 7-20 alkylaryl, or C 7-20 arylalkyl, and R 9 and R 10 are, the same as each other, C 1-20 alkyl.
  2. 2 . The metallocene supported catalyst of claim 1 , wherein the silica support has a mean particle size of 10 μm to 50 μm, the mean particle size of the silica support is determined by a particle size at a point where a volume-based cumulative distribution of particles according to a particle size reaches 50% when a particle size distribution is measured by the laser diffraction analysis, and has a Brunauer-Emmett-Teller (BET) specific surface area of 100 m 2 /g to 500 m 2 /g, and the BET specific surface area of the silica support is measured through a nitrogen gas adsorption/desorption analysis at 77 K using a specific surface area analyzer according to a BET method.
  3. 3 . The metallocene supported catalyst of claim 1 , wherein the silica support has a mean pore size of 1 nm to 30 nm, and the mean pore size is measured by obtaining a nitrogen gas adsorption/desorption isotherm at 77 K using a specific surface area analyzer and then by plotting the isotherm according to Barrett-Joyner-Halenda (BJH).
  4. 4 . The metallocene supported catalyst of claim 1 , wherein the metallocene supported catalyst comprises the nanosilica in an amount of 1 part by weight to 10 parts by weight with respect to 100 parts by weight of the silica support.
  5. 5 . The metallocene supported catalyst of claim 1 , wherein A is silicon, R 1 and R 5 are each independently a phenyl or naphthyl group, wherein the phenyl or naphthyl group is optionally substituted with C 3-6 branched alkyl, and R 9 and R 10 are, the same as each other, C 1-4 linear alkyl.
  6. 6 . The metallocene supported catalyst of claim 1 , wherein the transition metal compound is any one of the following compounds:
  7. 7 . The metallocene supported catalyst of claim 1 , further comprising one or more cocatalysts selected from the group consisting of compounds represented by the following Chemical Formula 2, Chemical Formula 3, and Chemical Formula 4: —[Al(R 11 )—O] m — [Chemical Formula 2] in Chemical Formula 2, a plurality of R 11 are the same as or different from each other, and each independently halogen; C 1-20 hydrocarbon; or C 1-20 hydrocarbon substituted with halogen; and m is an integer of 2 or more; J(R 12 ) 3 [Chemical Formula 3] in Chemical Formula 3, a plurality of R 12 are the same as or different from each other, and each independently halogen; C 1-20 hydrocarbon; or C 1-20 hydrocarbon substituted with halogen; and J is aluminum or boron; [E-H] + [ZQ 4 ] 31 or [E] + [ZQ 4 ] − [Checmical Formula 4] in Chemical Formula 4, E is a neutral or cationic Lewis base; H is a hydrogen atom; Z is a Group 13 element; and a plurality of Q are the same as or different from each other, and each independently a C 6-20 aryl group or a C 1-20 alkyl group in which one or more hydrogen atoms are optionally substituted with halogen, C 1-20 hydrocarbon, alkoxy, or phenoxy.
  8. 8 . The metallocene supported catalyst of claim 1 , wherein the metallocene supported catalyst further comprises a C 1-20 alkylaluminoxane-based compound as a cocatalyst.
  9. 9 . A method of preparing the metallocene supported catalyst of claim 1 , comprising: supporting the transition metal compound on the silica support; and adding the nanosilica to a transition metal compound-supported silica support, followed by mixing with each other to support the nanosilica on the silica support.
  10. 10 . The method of claim 9 , further comprising: supporting a cocatalyst by adding the cocatalyst to the silica support, and then heating at a temperature of 70 to 100° C., before supporting the transition metal compound on the silica support.
  11. 11 . A method of preparing an olefinic polymer, comprising polymerizing olefin monomers in presence of the metallocene supported catalyst of claim 1 .
  12. 12 . The method of claim 11 , wherein the olefin monomers comprise propylene.
  13. 13 . The method of claim 11 , wherein the olefinic polymer comprises a fine powder having a particle size of 75 μm or less in an amount of 2% by weight or less, based on a total weight of the olefin polymer.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) The present application is based on, and claims priority from, Korean Patent Application Nos. 10-2020-0134651 and 10-2021-0128298, filed on Oct. 16, 2020 and Sep. 28, 2021, respectively, the disclosures of which are hereby incorporated by reference herein in their entirety. TECHNICAL FIELD The present invention relates to a metallocene supported catalyst and a method of preparing an olefin polymer using the same. BACKGROUND ART Silica is mainly used as a support for a metallocene supported catalyst. To increase its catalytic activity, a metallocene as a main catalyst and a cocatalyst are supported by increasing the loading amounts thereof. However, as the loading amounts of the main catalyst and the cocatalyst increase, a large amount of the catalyst is exposed on the surface of the silica support, and thus catalyst leaching easily occurs, and the catalyst not tightly bound to the support is also leached through pores of the support. The leached catalyst forms fine powder to cause fouling in a reactor during a polymerization reaction of an olefin polymer. In particular, static electricity is generated during high-speed movement of powder, and fine powder has a relatively high surface area, and therefore, fine powder is easily agglomerated by static electricity to further increase reactor fouling. Accordingly, in order to prevent reactor fouling, a method of reducing the generation of fine powder by preventing the catalyst from leaching or by deactivating the leached catalyst, or a method of reducing the electrostatic properties of fine powder is required. As a traditional method of reducing the electrostatic properties of fine powder, a method of using an anti-fouling agent during preparation of polymers has been suggested. The anti-fouling agent, which is a material having a molecular structure including a hydrophilic group and a hydrophobic group at the same time, suppresses static electricity generated during preparation of polymers, thereby reducing reactor fouling. In addition, since the hydrophilic group of the anti-fouling agent generally includes a hydroxyl (—OH) structure, it may deactivate the catalyst present on the surface of the support or the leached catalyst. However, since the anti-fouling agent also deactivates the catalyst present inside the support, there is a problem in that the catalytic activity is greatly reduced. Accordingly, it is necessary to develop a method of preparing a metallocene supported catalyst capable of preventing the leaching phenomenon while improving catalytic activity. DETAILED DESCRIPTION OF THE INVENTION Technical Problem There are provided a metallocene supported catalyst capable of greatly reducing generation of fine powder during preparation of an olefin polymer while exhibiting excellent catalytic activity, and a preparation method thereof. There is also provided a method of preparing an olefin polymer, the method capable of preparing the olefin polymer having excellent physical properties by reducing generation of fine powder using the metallocene supported catalyst. Technical Solution According to the present invention, provided is a metallocene supported catalyst including a silica support including pores; a transition metal compound supported on the silica support; and nanosilica disposed on a surface of the silica support and has a mean particle size of 10 nm to 100 nm, wherein the mean particle size is determined by a particle size at a point where a number-based cumulative distribution of particles according to a particle size reaches 50% when a particle size distribution is measured by a laser diffraction analysis. Further, according to the present invention, provided is a method of preparing the above-described metallocene supported catalyst, the method including the steps of supporting the transition metal compound on the silica support; and adding, to the transition metal compound-supported silica support, nanosilica having a mean particle size of 10 nm to 100 nm, the mean particle size is determined by a particle size at a point where a number-based cumulative distribution of particles according to a particle size reaches 50% when a particle size distribution is measured by the laser diffraction analysis, followed by mixing with each other to support the nanosilica on the silica support. Further, according to the present invention, provided is a method of preparing an olefinic polymer, the method including the step of polymerizing olefin monomers in presence of the above-described metallocene supported catalyst. Advantageous Effects A metallocene supported catalyst according to the present invention may greatly reduce generation of fine powder while exhibiting excellent catalytic activity during preparation of an olefin polymer. As a result, it is possible to prevent reactor fouling caused by fine powder, and also to prevent a problem of a reduction in the classifying efficiency due to adhesion of fine powd