Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond

Definitions

• the present invention relates to a method for feeding a catalyst component to a reactor. More particularly, it relates to a method for continuously feeding to a reactor a catalyst component with a density of at least 1000 kg/m 3 for polymerization of an olefin.
• a catalyst component for olefin polymerization in this application is understood to be a transition metal compound (e.g. a metallocene complex or non- metallocene complex) or a specific boron or aluminum compound that is used as co- catalyst and/or scavenger.
• Said catalyst component may be a solid, containing large size particles with a particle diameter of several hundreds micrometers to several millimeters, and which has a low solubility in most solvents including saturated hydrocarbons used in the polymerization of polyolefins. Therefore, conventionally it has been used in a solution having not so high concentration or it has been used by adding an undissolved part of said catalyst component remaininq in solid form into a reactor.
• a problem of feeding an undissolved catalyst component into a reactor is that the solid catalyst component by sedimentation may cause a blockade in a feeding apparatus (for example, pump) or a feeding pipeline.
• EP-A-0889062 describes a method for feeding to a reactor a specific boron compound used as co-catalyst in the polymerization of a polyolefin with a maximum particle diameter is 50 /vm or less.
• the maximum particle diameter of 50 ⁇ m reduces the possibility of blockade in a feeding apparatus and the sedimentation velocity in a feeding pipeline tends to become lower.
• a particle diameter of 50 /vm or less can be obtained by pulverization, or by dissolving the catalyst component in a suitable solvent and then precipitating in a non-solvent.
• a disadvantage of this method is that it requires an additional treatment of the catalyst component to produce particles with a maximum particle diameter of 50/vm.
• a purpose of the invention is to provide a method for feeding a catalyst component in a diluent to a reactor, which does not require a maximum particle diameter of 50 ⁇ m, but still avoiding blockage in feeding equipment or pipelines.
• the method according to the invention is characterized in that the diluent has a density D with 0.9 p c ⁇ D ⁇ 1.1p c . wherein p c is the density of the catalyst component.
• p c is the density of the catalyst component.
• stable dispersion is formed, thus avoiding blockage in feeding equipment or pipelines.
• An additional advantage over the slurry proposed in EP-A-0889062 is that the method of the invention does not require a viscosity of the solvent that is preferably 0.8 cP (centipoise) (0,8.10 3 Pa. s) or more to reduce the sedimentation speed of the catalyst component.
• Diluents to be used in the method of the invention are typically diluents with a density of at least 1000 kg/m 3 .
• examples of such diluents are Bromobenzene, chloroform, dichloromethane, hexafluorobenzene, tetrachloroethane and perfluoroalkyl ether.
• a catalyst component with a density of more than 0.9 p c is sufficiently stable to avoid sedimentation to the bottom of a reactor.
• a catalyst component with a density of less than 1.1 p c is sufficiently heavy to avoid that the catalyst component starts floating to the surface of the slurry.
• the density of the diluent is between 0.95 p c and 1.05p c .
• the catalyst component is continuously fed to a reactor in the state of which the catalyst component is suspended or slurried in a diluent.
• the reactor herein refers to an apparatus suitable for a polymerization reaction as described above, comprising the catalyst component and include, for example, catalyst preparation apparatuses in which the above described catalyst component is continuously fed in a large scale to and reacted with another catalyst component e.g. a transition metal compound such as a metallocene complex, reacting with a co-catalyst.
• catalyst preparation apparatuses in which the above described catalyst component is continuously fed in a large scale to and reacted with another catalyst component e.g. a transition metal compound such as a metallocene complex, reacting with a co-catalyst.
• the reactors for olefin polymerization include, for example, reactors used for solvent polymerization or slurry polymerization in which an aliphatic hydrocarbon such as butane, pentane, hexane, heptane, octane or mixtures thereof is used as the solvent.
• an aliphatic hydrocarbon such as butane, pentane, hexane, heptane, octane or mixtures thereof is used as the solvent.
• a preferred one is a reactor for olefin polymerization by high- temperature solution polymerization in which the polymerization of olefins is carried out using a solvent such as hexane under conditions of 20 - 250 0 C and 2 - 200 kg/cm 2 at which polymers are melted or by high-pressure ionic polymerization in which the polymerization is carried out under a pressure of at least 30 MPa) and a temperature of at least 20 0 C. More suitably, it can be applied to a reactor for olefin polymerization by high-pressure ionic polymerization in which feed needs to be continued for a long period, and the advantage of the present invention is especially great.
• the feed to the reactor is suitably effected using a pump through a pipeline.
• the catalyst component in this application is understood to be a transition metal compound (e.g. a metallocene complex or non-metallocene complex) or a specific boron or aluminum compound that is used as co-catalyst and/or scavenger.
• a transition metal compound e.g. a metallocene complex or non-metallocene complex
• a specific boron or aluminum compound that is used as co-catalyst and/or scavenger.
• catalyst components with a density of less than 1000 kg/m 3 as these will form a stable slurry with conventional solvents used in olefin polymerization.
• a suitable transition metal compound for polyolefin polymerization is preferably an oranometallic compound represented by MLjXp, wherein M is a metal from group 3-11 , or the lanthanide series, X a monoanionic ligand bonded to M, L a neutral ligand bonded to M, j representing an integer denoting the number of neutral ligands L and p is the valence of the metal M.
• M is a metal from group 3-11 , or the lanthanide series
• X a monoanionic ligand bonded to M
• L a neutral ligand bonded to M
• j representing an integer denoting the number of neutral ligands L
• p is the valence of the metal M.
• a co-catalyst or scavenger for polyolefin polymerization comprises an aluminum compound.
• aluminum compounds are diisobutylaluminum hydride, C1-C20 trihydrocarbyl aluminum, and hydrocarbylaluminoxanes.
• a suitable boron compound used in polyolefin polymerization is a boron compound selected from (1 ) to (3) described below:
• G + is an inorganic or organic cation
• L is a neutral Lewis base
• (L-H) + is a Br ⁇ nsted acid.
• An additional advantage of the method of the present invention is that due to the stability of the slurry, a higher concentration of the catalyst component in the diluent can be applied, which allows a smaller storage vessel for the catalyst component. Density measurement of a catalyst component
• the density of a catalyst component is measured with a multivolume pycnometer 1305 from Micromeretics Instrument Corporation in following the instructions given in the Instruction Manual of 23 January 1987. This instrument is particular suitable for determining density of powders, porous materials and irregularly shaped solid objects.
• the density of diluents is measured in accordance with ASTM D891.
• Example I 1 gram TBF20 with an average particle size of about 200 ⁇ m and a density of 1670 kg/m 3 was dispersed in 5 ml perfluoroalkyl ether (Fomblin M03 oil) with a density of 1810 kg/m 3 , and allowed to stand for 14 days. After 14 days no precipitation or floating could be observed.
• 5 ml perfluoroalkyl ether Fomblin M03 oil
• TBF20 1 gram TBF20 with an average particle size of 200 ⁇ m was dispersed in 5 ml silicon oil with a density of 1040 kg/m 3 , and allowed to stand for 14 days. Within 1 day all TBF20 was precipitated.
• TBF20 1 gram TBF20 with an average particle size of 50 ⁇ m was dispersed in 5 ml hexane with a density of 660 kg/m 3 , and allowed to stand. TBF20 was precipitated within 1 minute.

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Citations (5)

• 2008
  • 2008-03-31 WO PCT/EP2008/002536 patent/WO2009121374A1/en active Application Filing

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