KR101464434B1 - A process for preparation of polyolefin comprising activation of a catalyst and prepolymerization - Google Patents

Abstract

The present invention relates to an olefin polymerization method comprising the activation of a catalyst including a transition metal compound and a prepolymerization process. According to the present invention, unstable process factors such as polymer coagulation and chunk generation can be mitigated and the activation of the catalyst can be improved in the process of polymerizing polyolefin using a single site catalyst.

Description

Technical Field [0001] The present invention relates to an olefin polymerization process comprising a catalytic activation and a prepolymerization process.

The present invention relates to an olefin polymerization process comprising an activation and a prepolymerization process of a catalyst comprising a transition metal compound.

Polyolefin resins such as polypropylene may be prepared in a polymerization reactor in the presence of a suitable catalyst. The propylene monomer may be introduced alone or in combination with one or more other monomers, such as ethylene, to produce a polypropylene homopolymer or copolymer. The propylene polymer is discharged from the reactor, is subjected to a suitable processing step and then extruded through a extruder and a die mechanism into a thermoplastic material to produce a propylene polymer as a special form of raw material, typically pellets. The propylene polymer pellets are finally heated and processed in the form of a predetermined final product. Examples of such end-products include fibers, (woven or non-woven) webs, films, pipes, containers and molded articles. Other examples of such products made of propylene polymers include components of durable articles such as automotive interior and exterior parts, and interior and exterior parts for household use.

One type of reactor suitable for the production of polypropylene homopolymers and copolymers is the Bulk CSTR reactor. The propylene injected into the reactor serves not only as a monomer for polymerization, but also as a diluent for dispersing the catalyst and as an emulsifier for removing heat generated during the polymerization. The polypropylene polymer produced from the continuously injected propylene and the unreacted propylene not participating in the reaction are continuously discharged. Two or more bulk continuous batch reactors may be connected, for example, continuously. In this way, in order to achieve certain polymer properties, the polymerization conditions of each reactor may be the same or different. Examples of polymerization conditions that can be varied include temperature, pressure, monomer content, co-monomer content, catalyst, co-catalyst and hydrogen concentration.

When a continuous batch reactor is used to copolymerize with a comonomer such as propylene and, for example, ethylene, the amorphous content is increased. Such an amorphous content causes the surface of the polymer polymerized in the reactor to become sticky or to escape into the liquid propylene as the reaction medium and to be deposited on the wall surface of the reactor, the agitator, or the tube wall for transfer. In the case of such a deposited polymer, it is deposited and grown as a chunk during operation, thereby providing instability factors in operation. Also, due to stickiness of the particle surface, aggregation may occur between the particles. Particularly, this phenomenon is caused by the reaction heat immediately after being injected into the reactor due to the initial high activity due to the characteristics of the catalyst, or the reaction is actively proceeded before the catalyst is dispersed.

Therefore, in general, when polypropylene is polymerized by using a continuous batch reactor, the particles of the catalyst are pre-polymerized in advance without comonomers to be injected into the reactor, thereby suppressing the initial reaction and allowing the reaction heat to be well dispersed in the reactor The way to control is well known. In the conventional method, a catalyst is dispersed in inert hydrocarbons such as hexane in a batch reactor, propylene polymerization is carried out to prepare a prepolymerized catalyst, and the catalyst is continuously introduced into a polymerization reactor. However, when such a method is used to pre-polymerize a single site catalyst such as a metallocene catalyst, the catalytic activity decreases and irregular particles are formed. In particular, nozzle clogging occurs during the injection of the prepolymerization catalyst, The decrease in activity was confirmed by the time of storage for the injection of the polymerization catalyst.

SUMMARY OF THE INVENTION The present invention has been made to overcome the problems of the prior art as described above, and it is an object of the present invention to increase the efficiency of a catalyst by introducing a catalyst activation process and an improved prepolymerization process to produce a polyolefin resin, And to provide an olefin polymerization method capable of maintaining the shape well and improving the stability of the polymerization process.

In order to solve the above problems, the inventors of the present invention have found that, in the production of a polyolefin using a conventional bulk continuous batch reactor, the content of the amorphous polymer increases and aggregation and chunks may occur between the particles, As a result, it is possible to improve this phenomenon through the new activation of the catalyst and the prepolymerization process as a result of repeated research to solve the problem during transport due to irregular particle shape or fouling caused by adhesion to the wall surface of the reactor And completed the present invention.

Accordingly, the present invention relates to a process for producing a prepolymerized catalyst, which comprises activating a catalyst containing a transition metal compound, continuously introducing an activated catalyst and an olefin monomer into a prepolymerization reactor, And then continuously injected into the polymerization reactor.

Hereinafter, the present invention will be described in detail.

Catalyst component

In the present invention, the catalyst containing the transition metal compound is preferably a catalyst containing a single active transition metal compound, specifically a Ziegler-Natta catalyst or a metallocene catalyst.

Typical Ziegler-Natta catalysts are stereospecific formed from transition metal halides and metal alkyl or metal halides, and are capable of producing isotactic polypropylene. Ziegler-Natta catalysts are derived from halides of transition metals, for example titanium, chromium or vanadium, and metal halides and / or metal alkyls, typically organoaluminum compounds, as cocatalysts. The catalyst typically consists of a titanium halide supported on a magnesium compound. The supported catalyst may be used with an alkyl aluminum compound, for example, a co-catalyst such as triethyl aluminum (TEAL), trimethyl aluminum (TMA), and triisobutyl aluminum (TIBAL). Conventional Ziegler-Natta catalysts can be used with one or more internal electron donors. These internal electron donors may be added during the preparation of the catalyst, combined with the support, or combined with other transition metal halides.

 Other catalyst systems useful for polymerizing propylene are based on metallocenes. However, unlike Ziegler-Natta catalysts, metallocenes have not traditionally been used in bulk continuous batch reactors, bulk loop reactors, gas phase fluidized bed reactors, and in particular commercial amounts of polypropylene homopolymers and / or copolymers Lt; / RTI > were not used in the bulk-loop reactor.

The metallocene is generally specified as a coordination compound into which at least one ligand coordinated with a transition metal via a [pi] bond has been introduced. The metallocene is typically a bulk ligand transition metal compound represented by the following general formula (1): < EMI ID =

[L] mM [A] n (1)

Wherein L is a bulk ligand, A is a leaving group, the ligands L and A may be bridged with each other, M is a transition metal, m and n are the total ligand valencies, .

As the metallocene compound represented by the general formula (1), the preferred metallocene compound may be a cyclopentadienyl ligand or a pre-sandwich compound having two or more ligands L which may be a cyclopentadiene-derived ligand, Sandwich compound having one ligand L which may be a pentadienyl ligand or a cyclopentadiene derived ligand. The transition metal atom (M) may be a transition metal of Group 4, 5 or 6 of the Periodic Table and / or a metal from the group of lanthanide and actinide. Zirconium, titanium and hafnium are particularly preferred. Other ligands A that may be bonded to the transition metal are living groups, such as, but not limited to, hydrocarbyl, hydrogen or other monoanionic ligands.

The metallocene compound which can be preferably used in the present invention is one in which a cyclopentadienyl (Cp) group is introduced, for example, a bridged metallocene represented by the following general formula (2)

RCpCp'MeQn ........ (2)

Wherein Me represents a transition metal element, Cp and Cp 'each represent a cyclopentadienyl group, which may be the same or different and may be substituted or unsubstituted, Q is alkyl or other hydrocarbyl or hydrogen group, n can be a number ranging from 1 to 3 and R is a structural bridge extending between the cyclopentadienyl rings.

The Cp and Cp 'groups in the general formula (2) may also include substitution by straight, branched, or cyclic hydrocarbyl radicals, and preferably other adjacent ring structures such as indenyl, And substitution by a cyclic hydrocarbyl radical to form a ring structure comprising a fluorenyl group. These additional ring structures may be substituted or unsubstituted by hydrocarbyl radicals, preferably C1-C20 hydrocarbyl radicals.

Various types of metallocene catalysts are known in the art, and as a specific example, metallocene catalysts and metallocene catalyst systems for producing isotactic polyolefins are disclosed in U.S. Patent Nos. 4,794,060 and 4,975,403 , All of which are incorporated herein by reference. These patents disclose stereorigid metallocene catalysts that polymerize olefins to form isotactic polymers, preferably the metallocene catalyst has a surface area of 100 to 400 m ² / g, a surface area of 0.5 to 3.5 cc / g, preferably 0.5 to 2 cc / g, particularly useful for the polymerization of high isotactic polypropylene.

For metallocene catalysts, typical supports may be such as talc, inorganic oxides, clay and clay minerals, ion exchange lamination compounds, diatomaceous earths, silicates, or zeolites, or resinous support materials such as polyolefins. Specific inorganic oxides include silica and alumina and are used alone or in combination with other inorganic oxides such as magnesia, titania, zirconia, and the like. Non-metallocene transition metal compounds, such as titanium tetrachloride, may also be introduced into the supported catalyst component. The inorganic oxide used as a support preferably has an average particle size of 5 to 100 microns and a specific surface area of 30 to 2000 m ² / g, more preferably an average particle size of 5 to 50 microns, and a specific surface area of 50 to 1000 m ² / g.

Any combination of metallocene compounds may be used for the practice of the present invention. Thus, unless otherwise indicated, the term "metallocene" as used herein includes a combination of two or more metallocene components as well as a single metallocene component.

The metallocene compounds may be used in combination with alkylation / elimination such as some form of activator (s) such as methylaluminoxane (MAO) and optionally trialkylaluminum compounds (TEAL, TMA and / or TIBAL) may be used in combination with a scavenging agent. The term "activator" is defined herein as any compound or component, or combination of compounds or components capable of promoting the ability of one or more metallocenes to polymerize an olefin to a polyolefin. Alkylaluminoxanes such as methylaluminoxane (MAO) are commonly used as metallocene activators.

In general, alkyl aluminoxanes contain n repeating units such as:

Wherein R is C1 to C8 alkyl including mixed alkyl. Particularly preferred are compounds wherein R is methyl. It is preferable that n is about 5 to 40.

Aluminoxane solutions, especially methyl aluminoxane solutions, are available from commercial vendors in solutions with varying concentrations (where the term "solution" includes suspension unless otherwise stated).

Various aluminoxane production processes are known and are described in U.S. Patent Nos. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 308,815, Limiting patents such as U.S. Patent Nos. 5,329,032, 5,248,801, 5,235,081, 5,103,031 and EP-A-0 561 476, EP-A-0 279 586, EP-A-0 594 218 and WO 94/10180 (Unless otherwise stated, the term "solution" means a mixture comprising a suspension).

Ionizing activators may also be used to activate metallocenes. These ionizing activators ionize the neutral metallocene compound either neutral or ionically. As a preferable example, there may be mentioned compounds such as tri (n-butyl) aluminum tetrakis (pentafluorophenyl) borate, and such ionizing compounds may be activated protons, or those coordinated with the residual ions of ionizing compounds, Or other cation that is only loosely coordinated.

Combinations of activators may also be used to activate the metallocene, for example a combination of aluminoxane and an ionizing activator, see WO 94/07928. The technology of ionic catalysts for coordination polymerization involving metallocene cations which are activated by non-coordinating anions is described in EP-A-0 277 003, EP-A-0 277 004 and U.S. Pat. No. 5,198, 401, Gt; WO92 / 00333. ≪ / RTI > These patent documents disclose that metallocenes (bis-Cp and mono-Cp) are hydrogenated by an anion precursor to cause alkyl / hydride groups to be extracted from the transition metal to be cationized and charge-balanced by non-coordinating anions A preferred process is disclosed. Suitable ionic salts include tetrakis-substituted borates or aluminum salts having fluoride aryl-moieties such as phenyl, biphenyl and naphthyl. The term "non-coordinating anion" ("NCA") refers to anions that do not coordinate to the cation or are only weakly coordinated to the cation and remain sufficiently displacable by the neutral Lewis base. "Compatible" non-coordinating anions are those that do not deteriorate to neutrality when the initially formed complex decomposes. Moreover, the anion does not transfer the anion substituent or fragment to the cation so that it forms a neutral byproduct from the neutral quadrature metallocene compound and the anion.

A preferred method for a supported ion catalyst comprising a metallocene anion and NCA is disclosed in U.S. Patent No. 5,643,847, U.S. Patent Application No. 09184389 filed on November 2, 1998, U.S. Patent Application filed on November 2, 1998 0.0 > 09184389. < / RTI > With the support component, these NCA support methods generally involve the use of a neutral anion precursor which is a Lewis acid strong enough to react with the hydroxyl-reactive functionality present on the silica surface to allow covalent attachment of the Lewis acid.

The use of ionizing compounds which are capable of producing active metallocene cations and non-coordinating anions, but which do not contain active proton is also known. See, for example, EP-A-0 426 637 and EP-A-0 573 403, which are incorporated herein by reference. An additional method of making the ionic catalyst utilizes ionized anionic precursors, such as tris (pentafluorophenyl) boran, which are initially neutral Lewis acids, but which form cations and anions in the ionization reaction with metallocene compounds, see EP- A-0 520 732, incorporated herein by reference. The ionic catalyst for addition polymerization can also be prepared by oxidizing a metal center of a transition metal compound with an anion group and an anion precursor containing a metal oxide group, see EP-A-0 495 375 for this. If the metal ligand comprises a halogen moiety (e.g., biscyclopentadienyl zirconium dichloride) that is not capable of ion extraction under standard conditions, they may be combined with lithium or aluminum hydride or alkyl, alkylaluminoxane, Grignard reagents, Can be converted through known alkylation reactions with the same organometallic compounds. For in situ processes describing the reaction of an alkyl aluminum compound with a dihalo-substituted metallocene compound with or without the addition of an active anion compound, see EP-A-0 500 944 and EP-A1-0 570 982, incorporated herein by reference.

As a specific example, if the activator is NCA, preferably NCA is first added to the support composition followed by addition of the metallocene catalyst. If the activating agent is MAO, preferably the MAO and the metallocene catalyst are dissolved together in a solution, and then the support is contacted with the MAO / metallocene catalyst solution. Other methods and order of addition will be apparent to those skilled in the art.

In the present invention, such a catalyst may be prepared and used as a diluting catalyst. As a preferred embodiment, in a polyolefin process in which polymerization is carried out in bulk or slurry, the catalyst can be used as a slurry state by diluting it with an inert hydrocarbon, typically a liquid diluent, and the diluted catalyst is subjected to pre- And then supplied to the reactor. The diluent catalyst may be activated before being fed to the prepolymerization reactor. The liquid inert hydrocarbons used for the dilution may be a nonpolar saturated hydrocarbon usually used and include n-hexane, cyclohexane, normal butane, isobutane, n-pentane, 1-methyl butane, n-heptane, do. In the preparation of the diluted catalyst, the ratio of the catalyst to the diluent may vary depending on the activity of the catalyst and the injection system. Preferably, it is preferred to dilute the catalyst per liter of diluent to a batch storage vessel containing an agitator in the range of 0.1 g / L to 30 g / L, preferably to be exhausted for 0.5 to 10 days after the preparation of the diluting catalyst .

Catalyst activation process

The olefin polymerization method of the present invention includes the step of activating the catalyst or the diluting catalyst by bringing into contact with the alkylaluminum compound before conducting the prepolymerization step. As a preferred embodiment, in the present invention, immediately before the catalyst or the diluting catalyst is injected into the polymerization reactor, the catalyst is contacted with the alkyl aluminum compound in the activation reactor as shown in FIG. 1, and then continuously injected into the polymerization reactor.

Preferably, the activation is carried out in a tubular activation reactor continuously connected to the prepolymerization reactor, wherein the alkyl aluminum compound is selected from the group consisting of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum and methylaluminoxane .

In the activation step of the catalyst, the ratio of the catalyst to the alkyl aluminum is preferably 1: 100 to 2,000 in terms of the molar ratio of the main active transition metal: alkyl aluminum compound in the catalyst, the activation time is 0.1 to 10 seconds, Is preferably -10 to 30 占 폚. Under such process conditions, the productivity of the catalyst, the shape of the polymer and the stability of the process can be maintained.

Pre-polymerization  fair

In the present invention, the activated catalyst or the diluted catalyst is preliminarily polymerized for a predetermined period of time in contact with the olefin monomer in a polymerization reactor continuously connected to the polymerization reactor, and then injected into the polymerization reactor.

It is preferable that the prepolymerization reactor is a tubular structure continuously connected to the polymerization reactor, and the pre-polymerization time is 0.5 to 5 seconds and the pre-polymerization temperature is 0 to 20 ° C. The injection rate of the pre-polymerization product (mixture of pre-polymerization catalyst and unreacted olefin monomer) is preferably 0.8 m / s or more. Under such process conditions, the productivity of the catalyst, the shape of the polymer and the stability of the polymerization process can be maintained.

Olefin polymerization

As described above, the mixture of the prepolymerized catalyst and the unreacted olefin monomer, which is the result of the selective catalytic activation and prepolymerization, is injected into the polymerization reactor continuously connected to the prepolymerization reactor, and further the olefin monomer is injected , Polymerization reaction (main polymerization) proceeds.

Examples of the olefin monomer used in the prepolymerization and the main polymerization in the olefin polymerization method of the present invention include C2 to C12 olefin monomers. Specific examples thereof include ethylene, propylene, butene, pentene, methylpentene, hexene, And the like. More preferred olefinic monomers are C2 to C3 olefin monomers, and propylene is particularly preferred. Also included are, for example, olefinically unsaturated monomers, C4 to C18 diolefins, conjugated or unconjugated dienes, polyenes, vinyl monomers and cyclic olefins. Non-limiting examples of other monomers include, for example, norbornene, norbornadiene, isobutylene, isoprene, vinylbenzocyclobutane, styrene, alkyl substituted styrene, ethylidene norbornene, dicyclopentane Dienes and cyclopentenes.

Polymers prepared by the olefin polymerization process of the present invention include, for example, homopolymers, copolymers or terpolymers.

The olefin polymerization reaction in the present invention is not particularly limited as long as it is carried out by injecting the result of the prepolymerization into the polymerization reactor as described above, and as a preferable specific example, Korean Patent Publication Nos. 2003-0045647, 10-2011 -0008000, and the like can be used.

That is, the olefin polymerization process according to the present invention can be carried out by a polymerization process in a solution phase, a gas phase, a slurry phase, a bulk phase, a high pressure process or a combination process thereof as described above and / And generally includes polymerizing one or more olefin monomers to form a polymer.

Specifically, the slurry process or the bulk process may be carried out continuously in one or more continuous batch (CSTR) or loop reactors. A slurry-like or dried, free powdery catalyst can be injected regularly into the reactor and, optionally, hydrogen can be added to the process for molecular weight control of the resulting polymer. The continuous batch reactor may be maintained at a pressure of, for example, from about 27 bar to about 50 bar, or from about 35 bar to about 45 bar, at a temperature of from about 38 ° C to about 121 ° C.

As one embodiment of the olefin polymerization process of the present invention, an example of a gas phase polymerization process may include a continuous cycle system wherein the circulating air stream is heated in the reactor by polymerization heat. The heat is removed from the circulating air stream in the other part of the cycle by the cooling system outside the reactor. Circulating air streams comprising one or more monomers can be continuously circulated through a fluidized bed in the presence of a catalyst under reaction conditions. The circulating air stream is generally removed from the fluidized bed and returned to the reactor. At the same time, the polymer product is withdrawn from the reactor and a new monomer is added to replace the polymerized monomer. The reactor pressure in the gas phase process may range, for example, from about 5 bar to about 30 bar. In a gas phase process, the reactor temperature may vary, for example, from about 30 캜 to about 120 캜, or from about 60 캜 to about 115 캜, or from about 70 캜 to about 110 캜 or from about 70 캜 to about 95 캜.

As one embodiment of the olefin polymerization process of the present invention, the slurry phase polymerisation process generally involves the formation of solid particulate polymer suspensions in a liquid phase polymerization medium with olefin monomers and optionally hydrogen added, with the catalyst. The suspension (which may include a diluent) is removed intermittently or continuously from the reactor, the volatile components are separated from the polymer and are optionally cycled to the reactor after distillation. The liquefied diluent used in the polymerization medium may include, for example, C3 to C7 alkanes (e.g., hexane or isobutane). The medium used is generally liquid under polymerization conditions and is relatively inert.

In one embodiment of the olefin polymerization process of the present invention, the bulk phase polymerization process is similar to the slurry phase process except that the liquid medium is a reactant (e.g., a monomer).

Alkylaluminum may be used to remove impurities in the raw materials used in the polymerization, wherein the total amount of alkylaluminum, including alkyl aluminum injected into the activating reactor in the catalytic activation process, is from 10 ppm to 300 ppm, .

According to the present invention, it is possible to improve the stability of the polymerization process and to improve the catalytic activity by preventing the unstable factors of polymerization of the polymer in the polymerization of the polyolefin using the single active site catalyst or generating chunks.

Fig. 1 is a diagram schematically showing a propylene polymerization process applied in Example 1 of the present invention. Fig.

Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples are merely preferred embodiments of the present invention, and the scope of the present invention is not limited by the following examples.

Example  One

As the catalyst, a conventional metallocene supported catalyst supported with Me ₂ Si (2-Me-4-Ph-Ind) ₂ ZrCl ₂ supported on the silica prepared in Example 1 of International Patent Publication No. WO2009 / Respectively.

Propylene was purified using adsorption column chromatography to remove impurities of propylene used in the polymerization reaction. The packing constituting the adsorption column was composed of molecular sieve 3A, molecular sieve 13X and Selecxsorb COS, and was activated for 24 hours at 270 ° C in a nitrogen atmosphere before use. Liquid construction rate of propylene through the adsorption column under a pressure of 40bar at room temperature (Liquid hourly space velocity) is 4hr ^- and ^1. All of the propylene used in the following is purified through the above adsorption column chromatography.

The diluted catalyst in which the metallocene supported catalyst was diluted with n-hexane and the triethylaluminum were injected into the catalytic activation reactor so that the molar ratio of Al in the triethylaluminum to the Zr in the catalyst was 300, And then continuously injected into the polymerization reactor. The purified propylene was injected into a prepolymerization reactor, prepolymerized at 10 ° C for 1 second with a catalyst, and then the resultant was continuously injected into a first continuous batch polymerization reactor. At this time, the injection rate of the mixture of the prepolymerized catalyst and the unreacted propylene injected into the reactor was such that the flux rate of the fluid was 1.1 m / s.

Also, propylene, ethylene and hydrogen were injected into the first polymerization reactor as an elimination compound, an antifouling agent and an additional monomer to be injected, and maintained at 70 캜. At this time, the amount of propylene charged into the first polymerization reactor was maintained at 40 kg / hr including the amount injected into the polymerization reactor, and the amount of catalyst input was 1 g / hr.

The mixture of the polymer discharged from the first polymerization reactor and the unreacted monomer was injected into a second continuous batch reactor to allow further polymerization to proceed. The amount of propylene charged into the second polymerization reactor was 5 kg / hr, and the temperature was adjusted to 64 ° C.

The mixture of the polymer discharged from the second polymerization reactor and the unreacted monomer was injected into the third gas-phase fluidized bed reactor to allow further polymerization to proceed. The amount of propylene charged into the third polymerization reactor was 6 kg / hr, and the temperature was adjusted to 75 ° C.

The amounts of hydrogen and ethylene were controlled according to the melt index and the ethylene content of the polypropylene produced in each polymerization reactor. The polymerization process was carried out for 48 hours to confirm the process stability.

Example  2

In Example 1, the injection amount of triethyl aluminum injected into the catalyst activation reactor was adjusted so that the molar ratio of Al to Zr was 600, the total polymerization reaction time was set to 3 seconds, and the amount of triethyl aluminum introduced into the first polymerization reactor The procedure of Example 1 was repeated except that the fluid linear velocity of the mixture of the polymerization catalyst and unreacted propylene was 1.5 m / s.

Comparative Example  One

The same procedure as in Example 1 was carried out except that the fluid linear velocity of the mixture of the prepolymerized catalyst and the unreacted propylene injected into the first polymerization reactor in the prepolymerization reactor in Example 1 was 0.5 m / s.

Comparative Example  2

Example 1 was carried out in the same manner as in Example 1, except that the injection amount of triethyl aluminum injected into the catalyst activation reactor was changed so that the mole ratio of Al to Zr became 1500.

Comparative Example  3

The procedure of Example 1 was repeated, except that the residence time in the catalyst activation reactor was changed to 20 seconds.

Comparative Example  4

The procedure of Example 1 was repeated, except that the residence time in the catalyst activation reactor was changed to 20 seconds.

Comparative Example  5

The procedure of Example 1 was repeated, except that the total polymerization time was changed to 0.1 second in the polymerization reactor in Example 1.

Comparative Example  6

The procedure of Example 1 was repeated except that the polymerization temperature was set at 40 캜 in the polymerization reactor in Example 1.

Comparative Example  7

Hexane and triethyl aluminum were injected into the non-continuous batch polymerization reactor, and the catalyst used in Example 1 was injected at a rate of 3.3 g / L. The molar ratio of Al to Zr was set to 300 at this time. Thereafter, while maintaining the temperature of the batch polymerization reactor at 10 ° C, the purified propylene was subjected to discontinuous pre-polymerization at a flow rate of 0.34 kg / hr as in Example 1 above. At this time, the weight ratio of propylene to the weight of the catalyst was adjusted to 5. The pre-polymerized catalyst was continuously injected into the first continuous batch polymerization reactor. At this time, the fluid linear velocity of the mixture of the prepolymerized catalyst and the unreacted propylene injected into the reactor was set to 1.1 m / s. The procedure of Example 1 was repeated except for the above-described contents.

The catalyst activity, ethylene content, polymer shape and process stability of the catalysts of Examples 1 to 2 and Comparative Examples 1 to 7 are shown in Table 1 below. The polymer shape was classified according to the degree of spherical original particle shape and the degree of aggregation. The process stability was classified according to the occurrence of clogging of the inlet end connected to the polymerization reactor and the reactor.

unit Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Activation
reaction


Alkyl
aluminum TEAL TEAL TEAL TEAL TEAL TEAL TEAL TEAL - catalyst
input g / hr One One One One One One One One - Al / Zr mol /
mol 300 600 300 1500 300 300 300 300 - Activation
time second One One One One 20 One One One - Activation
Temperature ℃ 10 10 10 10 10 10 10 10 - Pre-polymerization
reaction
Pre-polymerization
time second One 3 One One One 10 0.1 One - Pre-polymerization
Temperature ℃ 10 10 10 10 10 10 10 40 - Reactor
Injection rate m / s 1.1 1.5 0.5 1.1 1.1 1.1 1.1 1.1 1.1 PP
polymerization
reaction catalyst
productivity kgpp / g catalyst 10.5 9.8 10.7 4.5 7.3 9.1 10.7 7.6 1.5 Ethylene
content weight% 2.5 3 2 2.2 2.1 2.3 1.1 2.5 One polymer
shape Good Good Poor Good Good Good Poor Good Extremely
Poor fair
stability Good Good Poor Poor Poor Poor Poor Poor Poor

As can be seen from the results of the above Table 1, the examples show that the polymer is in the form of an intact spherical polymer with high activity as compared with the comparative examples, and that the injection line is not clogged during the pre-polymerization reaction and is operated stably Respectively. Therefore, it is possible to improve the catalyst productivity according to the catalyst activation condition and the pre-polymerization condition, to inhibit the formation of non-ideal shape polymer, and to improve the process stability.

Claims (11)

The catalyst containing the transition metal compound and the alkyl aluminum compound are brought into contact with each other at a molar ratio of aluminum in the transition metal: alkyl aluminum in the catalyst = 1: 100-2000 in the catalyst to activate the catalyst and the olefin monomer continuously, , And the mixture containing the pre-polymerization catalyst and the unreacted olefin is continuously injected into the polymerization reactor. The method according to claim 1,
Wherein the catalyst comprising the transition metal compound is a Ziegler Natta catalyst or a metallocene catalyst. The method according to claim 1,
Wherein said activation proceeds in an activation reactor continuously connected to said prepolymerization reactor. The method according to claim 1,
Wherein said alkyl aluminum compound is selected from the group consisting of trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trioctyl aluminum and methyl aluminoxane. delete The method according to claim 1,
Wherein the activation time is 0.1 to 10 seconds. The method according to claim 1,
Wherein the activation temperature is from -10 to 30 占 폚. The method according to claim 1,
Wherein the olefin is propylene. The method according to claim 1,
Wherein the prepolymerization reactor is a tubular reactor continuously connected to the polymerization reactor. The method according to claim 1,
Wherein the pre-polymerization time is from 0.5 to 5 seconds, and the pre-polymerization temperature is from 0 to 20 ° C. The method according to claim 1,
Wherein an injection rate of the mixture containing the pre-polymerization catalyst and the unreacted olefin injected into the polymerization reactor is 0.8 m / s or more.

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