KR20100024832A - Catalyst preparation method for polyolefin copolymerization - Google Patents

Abstract

PURPOSE: A method for preparing a catalyst for polyolefin copolymerization is provided to have no need of alkylaluminoxane and to maintain high activity by allowing the supported alkylaluminoxane to protect a metallocene compound from catalytic poison. CONSTITUTION: A method for preparing a catalyst for polyolefin copolymerization comprises the steps of: (i) dropping a hydrocarbon solvent 2~5 times of the micropore volume of a carrier, drying the hydrocarbon solvent in a nitrogen atmosphere at a room temperature so that the hydrocarbon solvent 0.5~1.5 times of the micropore volume in the carrier; (ii) dissolving the metallocene catalyst component in the alkylaluminoxane solution; (iii) adding the solution obtained from (ii) step to the carrier obtained from (i) step, and then supporting alkylaluminoxane and metallocene components by stirring the mixture; and (iv) washing and drying the supported catalyst obtained from (iii) step.

Description

Process for producing catalyst for polyolefin polymerization {CATALYST PREPARATION METHOD FOR POLYOLEFIN COPOLYMERIZATION}

The present invention relates to a method for preparing a metallocene supported catalyst for the polymerization of high activity polyolefin by supporting an alkylaluminoxane and a metallocene compound on a porous inorganic support, and more particularly, an alkylaluminoxane supported in a supported reaction step. And filling the fine pores of the silica used as a carrier with a hydrocarbon solvent having a low viscosity prior to the support so as to maximize the amount of the metallocene catalyst component, and removing only the solvent present outside the carrier by controlled drying. Supporting metallocene for high activity polyolefin polymerization, which minimizes the amount of the total solvent and prevents lowering of the concentration of alkylaluminoxane during the supporting reaction, so that the highly viscous alkylaluminoxane can easily penetrate into the micropores of the carrier. It relates to a method for producing a catalyst.

Metallocenes may be represented by the formula L _n MQ _p , where M is a metal of Group IIIB, IVB, VB or VIB; Q is a hydrocarbyl group or halogen having 1 to 20 carbon atoms; p is valence-2 of M, and L is a ligand bound to the metal M. Typically, the metallocene compound is used in combination with a cocatalyst methylaluminoxane (MAO) to prepare an olefin polymer and a copolymer.

The metallocene catalyst must be supported on an appropriate support in order to be used in a fluidized bed reactor or slurry reactor, and the individual catalyst particles loaded with metallocene must exhibit sufficient activity so as not to cause problems due to catalyst support residues.

Representative metallocene supported catalyst production method currently developed and used is a method in which a metallocene catalyst is supported on silica together with methylaluminoxane, which reacts the hydroxy group of the silica with methylaluminoxane to the surface of the silica. It is a method of supporting methyl aluminoxane and supporting the metallocene catalyst on the supported methyl aluminoxane. The metallocene catalyst component may be supported simultaneously with the methylaluminoxane or through additional reaction after the methylaluminoxane is supported. The activity of the supported catalyst is proportional to the amount of the metallocene component supported, and also to the amount of methylaluminoxane which assists the support of the metallocene catalyst component. Methylaluminoxane not only supports the metallocene catalyst but also serves to protect the metallocene catalyst component from the catalyst poison. Therefore, the supported amount of methylaluminoxane directly affects the activity of the catalyst.

As a method for preparing a metallocene supported catalyst, a method of adding a mixture of alkylaluminum such as trimethylaluminum or triethylaluminum to dehydrated silica and then introducing metallocene (see US Patent No. 4,937,217), Trimethylaluminum is added to silica that is not dehydrated, and then metallocene is introduced to dry and supported (see US Pat. Nos. 4,912,075, 4,937,301 and 4,935,397). Adding aluminoxane to produce aluminoxane in the carrier pores and then supporting metallocene (see US Pat. Nos. 5,008,228, 5,086,025 and 5,147,949), after calcining the inert support silica, the metallocene and the activating material (See US Pat. Nos. 4,808,561, 4,897,455 and 4,701,432) and the like are known. In addition, a method of mixing metallocene and alkylaluminum and then adding dehydrated silica (US Pat. No. 5,238,892), first, preparing a mixed solution of metallocene and aluminoxane, and adding a porous carrier to the solvent, A method for preparing a catalyst precursor suitable for pre-polymerization by removing the same has been disclosed (US Pat. No. 5,240,894).

However, when the metallocene supported catalyst is prepared by these methods, the supported state of the supported metallocene catalyst is unstable. It is difficult to obtain a desired level of activity due to the loss of a large portion in the washing step of the catalyst preparation process, or the catalyst component on the surface of the carrier particles is desorbed during the washing process. In addition, since the supported catalyst is prepared through several steps, the catalyst production time is long, the activity of the prepared catalyst is low, and when the supported catalysts prepared by the above method are used in the slurry polymerization process, the catalyst is soluble from the porous support. The component melts into the solvent, and the melted catalyst produces fine-sized polymer particles that accumulate inside the reactor or cling to the reactor walls. As the polymerization proceeds in the fine polymer stuck to the reactor wall as described above, fouling and plugging of the reactor are caused, and thus neither the continuous polymerization nor the batch polymerization process can be operated.

The problem of low activity and leaching of the supported metallocene catalyst is that the metallocene itself is physically bonded to the support rather than a chemical bond, so that the amount of loading itself is small and due to the hydroxyl group present on the surface of the silica used as the support. This occurs because the metallocene catalyst decomposes and loses activity. In addition, in order for the metallocene to exhibit high activity, an excess amount of methylaluminoxane should be used. When the methylaluminoxane solution is directly supplied to the gas phase reactor in a large amount sufficient to contact the metallocene compound, A liquid film layer is formed on the wall of the reactor, and the metallocene catalyst adheres to this portion, causing a problem that the polymerization reaction proceeds to form sheets and lumps. In order to solve the problem that the catalyst component on the support is desorbed during the washing step and the polymerization reaction in the supported catalyst process, another method is used. A representative method is a ligand of a metallocene catalyst using a hydroxyl group present on the surface of silica. To form chemical bonds (US Pat. Nos. 5,399,636, 5,466,766, 5,473,020 and US Patent Application 08 / 898,460). However, such a method requires a multi-step manufacturing process such as impurity removal and various separation steps, and thus requires a long time to prepare the catalyst, a high catalyst manufacturing cost, and a very small content of the metallocene catalyst to be supported. There is a problem that the activity per catalyst particle is very low, and additionally, methylaluminoxane should be used in the polymerization reaction.

Metallocene catalysts are known as catalyst systems for producing polyolefins having excellent physical properties with high activity and high copolymerization reactivity compared to conventional Ziegler-Natta catalysts. However, the metallocene catalyst is a homogeneous catalyst, and has a disadvantage in that it cannot be directly used in the process of producing particulate polymer of the same shape using a conventional particulate catalyst. Accordingly, there is a need for an improved method for supporting metallocene catalysts on appropriate supports.

Another problem of the supported metallocene catalyst has a problem that the activity decreases with time due to the change over time when the supported catalyst is stored in a dry state. In some cases, 50% of the initial activity is lost within 30 days. Therefore, commercially, a method of storing the solvent by replacing the solvent with mineral oil instead of vacuum drying is used in the last step of washing (US Pat. No. 6,777,366). However, the catalyst by this method has a disadvantage in that the injection method when used in the polymerization reactor has a disadvantage, and in order to change to a dry form, the excess solvent is used again and finally there is a disadvantage that the activity of the catalyst is similarly inferior. Therefore, in order to preserve the activity of the catalyst over time, a technique for increasing the methylaluminoxane content of the supported catalyst is required.

The size of the micropores of the silica carrier used for supporting the metallocene is about 50 to 500 mm 3, and it is important to increase the carrying efficiency of the metallocene and methylaluminoxane in the micropores. Methyl aluminoxane is a polymer that exists as a solid in itself at room temperature, and thus has high viscosity even under aromatic hydrocarbon solution. Therefore, methyl aluminoxane is difficult to penetrate into the carrier during the supporting reaction. In the conventional supporting method, in order to facilitate the fine pore penetration of methylaluminoxane, the carrier is made into a slurry with the same solvent as that used for preparing a solution of methylaluminoxane, and then a methylaluminoxane solution is added under stirring. (US Pat. No. 7,140,756), but in this case, the concentration of methylaluminoxane is lowered, so there is a disadvantage in that the carrying efficiency is lower.

The present invention, in order to solve the conventional problems as described above, by increasing the amount of the alkyl aluminoxane supported on silica sufficiently compared to the existing catalyst, there is no need to add alkyl aluminoxane during polymerization, the supported alkyl aluminoxane is metal The Rosene compound can be sufficiently protected from the catalyst poison to maintain high activity, and also prevent desorption and leaching during the reaction of the supported alkylaluminoxane and metallocene catalyst components in the washing step, and also the catalyst The polyolefin superposed | polymerized using this has a narrow molecular weight distribution, there is no gel, and it provides the manufacturing method of the catalyst for polyolefin superposition | polymerization which has the uniform copolymerization distribution of linear low density.

Method for producing a catalyst for polyolefin polymerization according to the invention is characterized in that it comprises the following steps:

(1) A hydrocarbon solvent corresponding to 2 to 5 times the micropore volume of the carrier is added dropwise, followed by dry evaporation of the hydrocarbon solvent in a nitrogen atmosphere at room temperature to leave a hydrocarbon solvent of 0.5 to 1.5 times the micropore volume on the carrier. step,

(2) dissolving the metallocene catalyst component in the alkylaluminoxane solution,

(3) adding the solution obtained in step (2) to the carrier obtained in step (1) and stirring at 40-160 ° C. to support the alkylaluminoxane and the metallocene component,

(4) washing the supported catalyst obtained from the above step (3) and drying and recovering it as a catalyst powder.

In the method for producing a polyolefin catalyst according to the present invention, the carrier used in the step (1) is a solid particulate porous, preferably an inorganic material, for example silicon and / or aluminum oxide, most preferably spherical Most preferred are silicas which exist in the form of particles, for example particles obtained by spray drying, and which have other functional groups containing OH groups or active hydrogen atoms.

The carrier has an average particle size of 10 to 250 microns, preferably an average particle size of 10 to 150 microns, an average diameter of 50 to 500 microns, and a micropore volume of 0.1 to 10 ml / g, preferably It is 0.5-5 ml / g, and the surface area of the said carrier is 5-1000 m <2> / g, Preferably it is 50-600 m <2> / g.

When silica is used as the carrier, it should have at least a part of active hydroxy [OH] group, the hydroxy group concentration is preferably 0.5 to 2.5 mmol or more per 1 g of the silica, more preferably 0.7 to 1.6 mmol / g, If it is less than 0.5 mmol, the supported amount of alkylaluminoxane decreases, which is not preferable. If it exceeds 2.5 mmol, the metallocene catalyst component is inactivated, which is not preferable.

The hydroxyl group of the silica can be detected by IR spectroscopy, and the hydroxy group concentration on the silica is determined by contacting the silica sample with methylmagnesium bromide and measuring the amount of methane foamed (by pressure measurement).

Silicas having [OH] concentrations and physical properties suitable for the present invention include W.R., which has a surface area of 300 m 2 / g and a pore volume of 1.6 ml / g. The brand names XPO-2402, XPO-2410, XPO-2411 and XPO-2412 available from Grace and Company's Davison Chemical Division can be used. Also, silicas such as Davision® 948, 952 and 955 can be purchased. It can be used by adjusting to the desired [OH] concentration through the heating process.

In the method for preparing a polyolefin catalyst according to the present invention, the step (1) is a pretreatment step for facilitating the fine pore penetration of the alkylaluminoxane into the carrier, and a hydrocarbon solvent 2 to 5 times the fine pore volume of the carrier. After adding to the carrier in advance, it is preferable to leave the hydrocarbon solvent in the carrier at 0.5 to 1.5 times the total volume of the micropores by evaporating and removing the hydrocarbon solvent existing outside the carrier under a nitrogen atmosphere at room temperature. The amount of aluminoxane supported is reduced, which is undesirable.

In the method for preparing a catalyst for polyolefin polymerization according to the present invention, the metallocene catalyst component used in the step (2) is not particularly limited in kind, but is preferably represented by the structure represented by the following formula (I) Have

(THI) ₂ R "MQ _p (I)

In the above formula (I), THI is a substituted or unsubstituted tetrahydroindenyl derivative, and R ″ is a structural crosslink that imparts steric stiffness between two THI groups; M is Group IIIB, Group IVB, Group VB Or a transition metal selected from group VIB, Q is a hydrocarbyl group or halogen having 1 to 20 carbon atoms, and p is valence-2 of M.

In the metallocene catalyst of formula (I), the two THI ligands may be the same or different, but the same is preferable.

Substitution patterns and numbering of the ligands of the catalyst of the invention are described in detail below.

When THI is substituted, this means that any position on THI may contain a substituent instead of a hydrogen atom. Thus, each substituted THI ligand may have a substituent on the 5-membered ring, a substituent on the 6-membered ring, or a substituent on both 5- and 6-membered rings.

Substituent positions of the THI ligands in the specification of the present invention are numbered 1 to 7 by the following notation system.

In order to distinguish the substitution in the first THI ligand and the second THI ligand of the two THI ligands, the second THI ligand is numbered by the same system as above, but is numbered 1'-7 '. In this type of catalyst, the position of the crosslinking of the two THI ligands is not particularly limited and is preferably 1,1'-crosslinked, 2,2'-crosslinked or 1,2'-crosslinked, 1,1 ' Crosslinking is most preferred.

The position of the substituent (s) on the two THI ligands is not particularly limited, but at least one THI ligand is substituted at the 2-position and / or 4-position (or 2'-position and / or 4'-position) It is preferable.

In one preferred embodiment, both THI ligands can be substituted. In this case, it is preferred to include substituents at the 2-position (2'-position) and / or 4-position (4'-position) of both THI ligands, and to the 2-position (2) of both THI ligands. Most preferably, they include a substituent at the '-position) and the 4-position (4'-position), and other positions in the THI ring may be substituted or unsubstituted.

Particularly preferred metallocene catalysts having 1,1'-crosslinking are 2; 4; 2,4; 2,2 '; 4,4 '; 2,4 '; 2,4,2 '; 2,4,4 '; And a substitution pattern of 2,4,2 ', 4', and only the positions indicated above include substituents. Here, since the basic structure of the two THI ligands is the same, for example, the substitution patterns of 2,4 'and 4,2' are the same THI substituent structure.

The kind of substituent (s) present on the THI ligand is not particularly limited, and when the THI ligand includes two or more substituents, these THI ligands may be substituted with the same substituents or different substituents.

Preferably, the substituents are independently selected from hydrocarbyl groups, alkyl groups, alkylsilicon groups, alkoxy groups, cycloalkyl groups, aryl groups and halogens having 1 to 20 carbon atoms. Examples thereof include phenyl (Ph), benzyl (Bz), naphthyl (Naph), indenyl (Ind) and benzindenyl (BzInd), methyl (Me), ethyl (Ethyl), n-propyl (n- Pr), i-propyl (i-Pr), n-butyl (n-Bu), t-butyl (t-Bu), trimethylsilicon group (Me ₃ Si), alkoxy (preferably RO, where R is C _1-20 alkyl), cycloalkyl and the like, and halogen. The most preferred substituent at the 2-position of THI is a methyl group. Most preferred substituents at the 4-position of THI are phenyl, naphthyl or benzindenyl.

In one preferred embodiment, examples of THI derivative ligands include 2-Me, 4-PhTHI; 2-Me, 4-NaphTHI; Or 2-Me, 4,5-BzIndTHI.

The type of R ″, which is a crosslinking present between two THI rings in the metallocene catalyst component of formula (I), is not particularly limited, but is preferably an alkylidene group having 1 to 20 carbon atoms , Alkylenyl group, germanium group (eg dialkylgernium group), alkylsilicon group (eg dialkylsilicon group), siloxane group (eg dialkylsiloxane group), alkylphosphine group or amine group Most preferably, ethylenyl radical (-CH ₂ CH _2- ) or Me ₂ Si.

The metal M in the metallocene catalyst of formula (I) is a transition metal selected from group IIIB, IVB, VB or VIB of the periodic table of the elements, preferably selected from Ti, Zr, Hf and V.

Q in the metallocene catalyst of formula (I) is preferably halogen, in particular Cl.

And since the valence of the said metal M is four, p becomes 2 normally.

The most preferred metallocene catalyst components used in the present invention are as follows:

Et (THI) ₂ ZrCl ₂ ,

Me ₂ Si (THI) ₂ ZrCl ₂ ,

Me ₂ Si (2-MeTHI) ₂ ZrCl ₂ ,

Et (2-MeTHI) ₂ ZrCl ₂ ,

Me ₂ Si (2-Me, 4-PhTHI) ₂ ZrCl ₂ ,

Et (2-Me, 4-PhTHI) ₂ ZrCl ₂

Me ₂ Si (2-Me, 4-NaphTHI) ₂ ZrCl ₂ ,

Et (2-Me, 4-NaphTHI) ₂ ZrCl ₂ ,

Me ₂ Si (2-Me, 4,5-BzIndTHI) ₂ ZrCl ₂ ,

Et (2-Me, 4,5-BzIndTHI) ₂ ZrCl ₂ .

The catalyst system of the present invention is not particularly limited, but may include one or more metallocene catalyst components as described above. It may also further comprise other known catalyst components in addition to the additional catalyst, if desired, for example the metallocene catalyst component according to the invention.

Metallocene catalyst components used in the present invention are described in the literature. Spalek; A. Antberg, J. Rohrmann, A. Winter, B. Bachmann, P. Kiprof, J. Behm, and W. A. Hermann, Angew. Chem. Int. Eng. Ed. 1992, 31, 1347, or commercially available from mCAT GmBH (Geschuftfuhrer Dr Markus Ringwald Handelsregister Freiburgi HRB 381812).

The alkylaluminoxane used in step (2) includes a straight chain and / or cyclic alkylaluminoxane oligomer, and when the alkylaluminoxane is a linear alkylaluminoxane oligomer, the formula R- (Al (R) -O) _n- AlR ₂ , and in the case of cyclic alkylaluminoxane oligomers, represented by the formula (-Al (R) -O-) _m , where R is a C ₁ -C ₈ alkyl group, preferably methyl and n are 1-40, Preferably it is 10-20, m is 3-40, Preferably it is 3-20. The alkylaluminoxane is a mixture of oligomers having a very wide molecular weight distribution, usually having an average molecular weight of about 800 to 1200, mainly maintained in solution in toluene, and in particular, 10% or 30% methylaluminum produced by Albemarle. Noxic acid, and the like.

In the solution resulting from the above step (2), the concentration of the alkylaluminoxane is 5 to 30% by weight, and the concentration of the metallocene catalyst component is preferably 0.001 to 0.1% by weight, calculated as the metal element (M). If the concentration of each component is out of the above range, the catalytic activity is lowered, which is not preferable.

The solution comprises an aromatic hydrocarbon, aliphatic hydrocarbon or aliphatic ring hydrocarbon as solvent.

In the step (3), the supporting process, preferably, after the alkyl aluminoxane is supported on the carrier, the metallocene is supported. When silica is used as the carrier, the hydroxy group of the silica under anhydrous conditions without oxygen, alkyl aluminium It reacts with the oxidic acid to support the alkylaluminoxane to provide a site on which the metallocene is to be supported, and at the same time, it is very sensitive to the external catalyst poison to protect the metallocene that is easily lost. Therefore, the higher the supported amount of the alkylaluminoxane, the higher the supported amount of the metallocene, and the higher the probability of not being poisoned by external catalyst poison, thereby increasing the activity.

The temperature of the supporting process of step (3) is preferably 40 ~ 160 ℃, more preferably 80 ~ 120 ℃, outside the temperature range is not preferred because the activity is lowered, the supporting time is 30 minutes ~ It is preferable that it is 4 hours, and 1 to 2 hours are more preferable. If it is out of the said time range, the amount of support decreases and is not preferable.

A small amount of unreacted alkylaluminoxane and unsupported metallocene catalyst is present in the supported catalyst solution in which the supported process of step (3) is completed, and these need to be removed before the drying process, and the unreacted alkylaluminoxane is not removed. In this case, the supported catalysts stick to each other and cause a poor injection problem when the catalyst is injected into the polymerization reactor in a dried form, and the injection of the agglomerated catalyst causes local overreaction in the reactor to form sheets and agglomerates. Will cause problems. In addition, the unsupported metallocene is easily separated from the carrier during the polymerization reaction to form a polymer of very fine particles, causing problems of reactor fouling.

For the purpose of removing such unsupported substances, the washing in the step (4) is preferably washed twice with an organic solvent such as an aromatic hydrocarbon solvent or an aliphatic hydrocarbon solvent. There is no particular limitation on the solvent used in the washing step, but it is preferable to use an aromatic hydrocarbon solvent in the first wash and an aliphatic hydrocarbon solvent in the second wash. In the first washing step, mainly unsupported metallocene and alkylaluminoxane are removed. If desorption of the supported metallocene occurs in this step, it acts as a factor to lower the activity of the supported catalyst. It is preferable to carry out at a temperature of -40 to 120 ° C, preferably -20 to 60 ° C, more preferably 10 to 30 ° C. The secondary washing temperature is not particularly limited but is preferably room temperature (about 25 ° C).

Drying in the step (4) can be carried out using a conventional drying process.

The Al content in the metallocene supported catalyst prepared according to the method of the present invention as described above is preferably 20% by weight or more, but less than 20% by weight is not preferable because the activity is lowered.

The polyolefin polymerization method using the catalyst for polyolefin polymerization prepared by the production method according to the present invention includes hydrogen, olefin, and comonomer as necessary in the presence of a metallocene supported catalyst prepared as described above as a main catalyst. An olefin polymer or copolymer is prepared by reacting the gas phase polymerization composition.

The olefin may be ethylene. In this case, the comonomer is preferably an alpha-olefin other than ethylene such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and the like. The content ratio of ethylene is from 0.005 to 0.02 in molar ratio of comonomer / ethylene, preferably from 0.008 to 0.015. In this case, if the comonomer / ethylene molar ratio is less than 0.005 or more than 0.02, the desired level of copolymer cannot be obtained.

In such a method of preparing an olefin (co) polymer, the metallocene catalyst is combined with one or more activators to form an olefin polymerization catalyst system. Preferred activators used in this case include alkylaluminum compounds (e.g. diethylaluminum chloride), aluminoxanes, modified aluminoxanes, neutral or ionic ionizing activators, noncoordinating anions, noncoordinating group 13 metal or metalloid anions, boranes And borate salts.

With the alkyl aluminum compound has the general formula AlR _n X _(3-n) alkyl aluminum compounds represented by (wherein, R is an alkyl group of carbon number 1 ~ 16, X is a halogen element, and 1≤n≤3) Can be used. Specific examples of the alkyl aluminum compound are preferably triethyl aluminum, trimethyl aluminum, trinormal propyl aluminum, trinormal butyl aluminum, triisobutyl aluminum, trinormal hexyl aluminum, trinormal octyl aluminum, tri2-methylpentyl Aluminum etc. are used, Especially preferably, triisobutyl aluminum, triethyl aluminum, trinormal hexyl aluminum, or trinormal octyl aluminum is used.

It is preferable to use the said alkylaluminum compound at the time of gas phase superposition | polymerization in the following molar ratio according to desired polymer property.

1 ≦ transition metal in alkylaluminum compound / main catalyst ≦ 1000

More preferably

10 ≦ alkyl aluminum compound / transition metal in main catalyst ≦ 300

If the molar ratio of the transition metal in the alkylaluminum compound / main catalyst is less than 1 kPa, sufficient polymerization activity cannot be obtained, whereas if it exceeds 100, the adverse effect of lowering the polymerization activity appears.

In the above olefin (co) polymer production method, the polymerization reaction is preferably in the absence of a hydrocarbon solvent, preferably at a temperature of 60 to 120 ° C, more preferably 65 to 100 ° C, most preferably 70 to 80 ° C, and Preferably it is carried out at a pressure of 2 to 40 atmospheres, more preferably 10 to 30 atmospheres.

If the polymerization temperature in the reactor is less than 60 ° C., sufficient polymerization efficiency cannot be obtained. If the polymerization temperature is more than 100 ° C., there is a problem that a polymer mass is easily generated. In addition, when the operation pressure in the reaction reactor is less than 2 atmospheres, the ethylene partial pressure is low to obtain sufficient polymerization efficiency. When it exceeds 40 atmospheres, control of the reaction becomes difficult, and the reactor is exerted.

According to the present invention, the supported amount of the alkylaluminoxane and the metallocene compound to be supported is increased to activate the effectively supported metallocene catalyst component without the need for additional injection of the alkylaluminoxane during the polymerization reaction, and the supported metallocene The compound is sufficiently protected from the catalyst poison for a long time, so that the change over time is extremely small, and it has the effect of maintaining high activity.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example  One

[Preparation of supported metallocene catalyst]

Dehydrated silica having a trade name XPO-2402 (average particle size of 50 microns, surface area of 300 m 2 / g, micropore volume of 1.6 ml / g, and OH concentration of 1 mmol / g) was quantified 5 g under anhydrous conditions, and 30 ml of toluene was previously added. Toluene, which is external to XPO-2402, was removed by drying and evaporating at room temperature under nitrogen atmosphere, and thus XPO-2402 was free flowing again. It was injected into a 1 L reactor equipped with a stirrer and a cooling condenser. 75 ml of methylaluminoxane solution (10% by weight in toluene) was quantified in a measuring cylinder, and then mixed with 0.3 g of the metallocene catalyst component Et (THI) ₂ ZrCl ₂ , pre-quantified in 250 ml Schlenk, at room temperature. The mixture was stirred for 5 minutes to dissolve and react with the solid metallocene catalyst.

The methylaluminoxane-metallocene solution was added while maintaining the temperature of the reactor at 70 ° C. After stirring, the reaction temperature was raised to 110 ° C. At this temperature, the supporting reaction proceeded for 90 minutes. After the reaction was completed, the reaction was transferred to a Schlenk vessel, followed by decantation. After the reaction was stirred, the mixture was allowed to stand for 10 minutes, followed by decantation of the upper solution, and the reaction was first washed with 100 ml of toluene at room temperature. After the reaction was stirred, the reaction solution was allowed to stand, and after standing up, the upper solution was decanted and washed twice with 100 ml of toluene at room temperature. Thereafter, the obtained catalyst system was washed with purified hexane and then dried under mild vacuum. The amount of supported catalyst prepared was 9.5 g. Al and Si content analysis of the catalyst were carried out to calculate the amount of methylaluminoxane supported from the Al content. The measured Al content was 27.33% by weight, and the calculated amount of supported methylaluminoxane was 58.7% by weight. Carrier preparation conditions and analysis results are summarized in Table 1.

[Polymerization method]

Under the conditions shown in Table 2, polymerization was carried out by the following method using the metallocene supported catalyst described above.

1000 ml of purified hexane and 10 ml of 1-hexene were injected into a 2 L stainless steel reactor equipped with a stirrer and a heating / cooling device. The reactor was thoroughly washed with pure nitrogen before use. Next, 0.5 cc of 1 M hexane dilution solution of triisobutylaluminum (TiBA) was injected into the reactor as a catalyst poison removing agent, and the mixture was stirred, and the temperature was raised to 65 ° C, followed by stirring. As a main catalyst, 18 mg of the metallocene supported catalyst prepared in the above step was quantified in a glove box, transferred to a 5 ml syringe, and 1.7 cc of 1 M hexane dilution of triisobutylaluminum (TiBA) was taken as an activator. The activated catalyst slurry was transferred to the reactor and injected into the reactor at 65 ° C. Then, the reactor temperature was raised to 80 ° C., 150 ml of hydrogen was supplied, ethylene was fed so that the reactor voltage was 300 psig, and the reaction was started by stirring at 1000 rpm. During the reaction, the polymerization was carried out for 45 minutes while supplying enough ethylene so that the voltage of the reactor was kept constant at 300 psig. After 45 minutes of polymerization, ethylene injection was stopped to terminate the reaction to obtain a resultant polymer. The obtained polymer was separated by a filter and sufficiently dried to obtain 201 g of a polymer. The polymerization results are summarized in Table 2.

Comparative example  One

After adding toluene to silica as a carrier, injecting a methylaluminoxane-metallocene solution in a carrier slurry containing 30 ml of toluene without performing a process of drying evaporating toluene under a nitrogen atmosphere, and then completing the supporting reaction. A supported catalyst was prepared in the same manner as in Example 1 except that the first wash was performed at 110 ° C, except that 18.5 mg of the catalyst was used in the polymerization process and the polymerization reaction time was 60 minutes. The polymerization was carried out in the same manner as in Example 1. 205 g of polymer was obtained. Carrier preparation conditions and analysis results are summarized in Table 1, and the polymerization results are summarized in Table 2.

Comparative example  2

The supported catalyst was prepared in the same manner as in Example 1, except that the supported reaction was carried out at 100 ° C. without adding toluene to silica as a carrier in advance, and the first washing was performed at 80 ° C. after the completion of the supported reaction. . The polymerization process was carried out in the same manner as in Example 1 except that the amount of the catalyst was 26.5 mg and the polymerization time was 30 minutes. 178 g of polymer was obtained. Carrier preparation conditions and analysis results are summarized in Table 1, and the polymerization results are summarized in Table 2.

Example  2

The polymerization was carried out in the same manner as in Example 1 30 days after the metallocene supported catalyst obtained in Example 1 was stored in a vessel under a nitrogen atmosphere. 19 mg of catalyst was used, the polymerization time was 30 minutes, and the polymer was 138 g. The polymerization results are shown in Table 3.

Comparative example  3

The polymerization was carried out in the same manner as in Example 1 30 days after the metallocene supported catalyst obtained in Comparative Example 1 was stored in a vessel under a nitrogen atmosphere. 17mg of catalyst was used, polymerization time was 30 minutes, and polymer was obtained 85g. The polymerization results are shown in Table 3.

Comparative example  4

The polymerization obtained in Comparative Example 2 was carried out in the same manner as in Example 1 30 days after storage in a vessel under a nitrogen atmosphere. The catalyst was 25 mg, polymerization time was 30 minutes, the polymer was 121g. The polymerization results are shown in Table 3.

TABLE 1

Example 1 Comparative Example 1 Comparative Example 2 XPO-2402 (g) 5 5 5 Carrier Pretreatment Toluene was added beforehand and dried under nitrogen atmosphere. Toluene was added in advance but not dried under nitrogen atmosphere. Toluene is not added beforehand. Support reaction temperature (℃) 110 110 100 Primary washing (℃) Room temperature 110 80 Yield (g) 9.5 7.4 6.2 Aluminum content (% by weight) 27.33 19.2 14.1 Methyl aluminoxane (% by weight) 58.7 41.2 30.4

TABLE 2

Example 1 Comparative Example 1 Comparative Example 2 Aluminum (% by weight) 27.33 19.2 14.1 Metallocene catalyst (mg) 18 18.5 26.5 Polymerization time (minutes) 45 60 30 Yield (g) 201 205 178 Activity (g / g / h) 14,889 11,081 13,434

TABLE 3

Example 2 Comparative Example 3 Comparative Example 4 Aluminum (% by weight) 27.33 19.2 14.1 Metallocene catalyst (mg) 19 17 25 Polymerization time (minutes) 30 30 30 Yield (g) 138 85 121 Activity (g / g / h) 14,526 10,118 9,680 Active retention rate (%) 97.6 91.3 72.1

As shown in Table 2, Example 1 can be seen that the higher the aluminum content supported in the catalyst than the Comparative Examples 1 and 2, the activity is excellent, and as shown in Table 3, the higher the supported aluminum content in the catalyst It can be seen that the polymerization activity retention rate is high.

Claims (4)

A process for preparing a catalyst for polyolefin polymerization, comprising the following steps: (1) A hydrocarbon solvent corresponding to 2 to 5 times the micropore volume of the carrier is added dropwise, followed by dry evaporation of the hydrocarbon solvent in a nitrogen atmosphere at room temperature to leave a hydrocarbon solvent of 0.5 to 1.5 times the micropore volume on the carrier. step, (2) dissolving the metallocene catalyst component in the alkylaluminoxane solution, (3) adding the solution obtained in step (2) to the carrier obtained in step (1) and stirring at 40-160 ° C. to support the alkylaluminoxane and the metallocene component, (4) washing the supported catalyst obtained from the above step (3) and drying it, and then watering it as catalyst powder. According to claim 1, wherein the carrier has an average particle size of 10 ~ 250 microns, has an average diameter of 50 ~ 500 microns, micropore volume of 0.1 ~ 10ml / g, the surface area of the carrier is 5 ~ 1000 It is a silica of m <2> / g, The manufacturing method of the catalyst for polyolefin polymerization characterized by the above-mentioned. The method for preparing a catalyst for polyolefin polymerization according to claim 1, wherein the metallocene catalyst component is represented by the following general formula (I): (THI) ₂ R "MQ _p (One) (Wherein THI is a tetrahydroindenyl derivative, which may be substituted or unsubstituted, R ″ is a crosslinking present between two THIs, and M is a transition metal selected from Groups IIIB, IVB, VB and VIB) Q is a hydrocarbyl group or halogen having 1 to 20 carbon atoms, and p is valence-2 of M). According to claim 1, wherein the concentration of the metallocene catalyst component in the solution resulting from the step (2) is calculated as the metal element in the metallocene catalyst component is 0.001 ~ 0.1% by weight, the concentration of the alkyl aluminoxane is 5 ~ It is 30 weight%, The manufacturing method of the catalyst for polyolefin polymerization characterized by the above-mentioned.