JPS6149321B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a catalyst for ethylene polymerization. More specifically, the present invention relates to an ethylene polymerization catalyst that can produce an ethylene polymer having various suitable properties by a gas phase method with relatively high productivity. To be industrially useful, for example, in gas phase processes, such as the fluidized bed processes of US Pat.
The catalyst used must be a highly active catalyst, ie it must have a productivity level of 500,001 b, preferably 1,000,001 b of polymer per 11 b of main metal in the catalyst. This is because this type of gas phase process usually does not use any solvent residue removal step. Therefore, the catalyst residue in the polymer is
If it remains in the polymer, it must be sufficiently low so as not to cause any undue problems at the hands of the resin processor and/or end consumer.
When highly active catalysts are successfully used in such fluidized bed processes, the heavy metal content of the resin is on the order of 20 ppm of major metals at a productivity level of 500,000. A low catalyst residue content is also important when the catalyst is made with chlorine-containing materials, such as chlorides of titanium, magnesium and/or aluminum, which are used in so-called Ziegler or Ziegler-Natsuta catalysts. . High residual chlorine levels in molding resins cause pitting and corrosion on the metal surfaces of molding equipment. Molding grade resins with residual chlorine of around 200 ppm are not industrially useful. U.S. Pat. Nos. 3,922,322 and 4,035,560 disclose the use of several Ti- and Mg-containing catalysts for the production of granular ethylene polymers in a gas-phase fluidized bed process at pressures below 100 psi (70 Kg/cm ² ). Use is disclosed. However, the use of these catalysts in these processes has significant drawbacks. The catalyst of US Pat. No. 3,922,322, according to the examples of this patent, provides polymers with extremely high catalyst residue contents, ie, about 100 ppm Ti and about 300 ppm or more Cl. Furthermore, as disclosed in the examples of U.S. Pat. No. 3,922,322, the catalyst is used in the form of a prepolymer and the catalyst composition has a very high volume relative to the volume of polymer produced in the reactor. must be fed to the reactor. Therefore, the production and use of this catalyst requires the use of relatively large equipment for catalyst production, storage, and transportation. The catalyst of U.S. Pat. No. 4,035,560 also gives a polymer with an apparently high catalyst residue content, and the catalyst composition is apparently pyrophoric due to the type and amount of reducing agent used in this type of catalyst. be. U.S. Patent No. issued April 27, 1976
No. 3,953,414 describes the polymerization of olefins using catalysts prepared from supported catalyst-forming components, the polymers being in particle form with the shape of the supported components being spherical or elongated. The catalyst is (a)
A catalyst-forming component of an organometallic compound of a metal belonging to a group or a group of the periodic table is prepared by (b) a carrier made of anhydrous magnesium halide and a halogenated titanium compound chemically bonded to or dispersed in this carrier. It is produced by mixing the product with a support component. Component (b) is in the form of spherical or oblong particles having dimensions of 1 to 350 microns. Component (b) of the catalyst is prepared in various ways, one of which consists of spraying a solution of anhydrous dimagnesium halide in an organic solvent. The atomization is carried out in such a way as to obtain spherical particles with a size of 1 to 300 microns. Removal of the solvent bound to the carrier is
This is accomplished by conditioning the particles under reduced pressure.
The carrier particles are then contacted with a halogenated titanium compound. The examples in this patent disclose the use of catalysts in slurry polymerization processes. U.S. Patent No. 5, issued September 5, 1978
No. 4,111,835 describes the polymerization of olefins to produce long spheroidal resin particles, which are extremely crush resistant when the polymerization is carried out on a continuous scale. The catalyst comprises (a) an organometallic compound of a metal of group 1 or group of the periodic table; and (b) a halogenated titanium compound in an aqueous magnesium halide in the form of oblong particles having a particle size of 10 to 70 microns. and the product obtained by the reaction. Magnesium halide hydrate contains 10-45% by weight of water, which is produced by direct combination synthesis from electrolytic magnesium and hydrochloric acid and then by fractional crystallization of this synthetic product. Obtained by partial dehydration. Spherical particles are obtained by spray drying the magnesium halide hydrate.
The magnesium halide hydrate used as a carrier can be mixed with 20 to 80% by weight of a cocarrier that is inert to magnesium halides and is a compound belonging to Groups ~ of the Periodic Table. can. The examples in this patent describe the use of catalysts in slurry polymerization processes. i.e., U.S. Patent No. 3,953,414 and
No. 4,111,835 describes the production of ethylene polymers using catalyst components produced by a patent and exemplifying a slurry polymerization process, where the components of the catalyst (catalyst support) are spray-dried. Forms long spherical particles. Furthermore, the methods of these patents are carried out using high concentrations of boiling TiCl ₄ which is extremely corrosive.
It also involves a complex multi-step process. Furthermore, these patents describe the use of hydrates containing water. This water can have a negative effect on the activity of the catalyst. F.G. Karol et al. entitled "Production of Ethylene Copolymers in a Fluidized Bed Reactor". Filed on March 31, 1978 and February 27, 1979
No. 892,325, refiled as Application No. 014414 on D.A.
If an ethylene copolymer with a melt flow rate of 22-32 and a relatively low residual catalyst content is used, the monomers can be transferred into the gas phase using a specific highly active Mg-Ti-containing composite catalyst blended with an inert support material. It is disclosed that if polymerized by a process, it can be produced in granular form with relatively high productivity. The granular polymers thus produced have excellent physical properties that allow their use in a wide range of molding applications. Filed March 31, 1978 by B.E. Wagner et al. entitled "Polymerization Catalyst, Process for its Preparation and Use thereof for Ethylene Homopolymerization" and
U.S. Patent Application No. 892,037, refiled as Application No. 014412 on February 27, 1979, is 0.958
If an ethylene homopolymer with a density range of ~0.972 and a melt flow rate of 22-32 and a relatively low residual catalyst content is used in the presence of a highly active magnesium-titanium composite catalyst blended with an inert support material, It is disclosed that if ethylene is homopolymerized in a low pressure gas phase process, it can be produced for industrial purposes at relatively high productivity. U.S. Patent Application Nos. 892325 and 892037, cited above.
No. 014414 and No. 014412 are hereinafter referred to as prior U.S. patent applications. However, the polymer produced by the blended catalyst of the prior US patent application has the disadvantage that the polymer particles produced during the fluidized bed polymerization process have an irregular shape and are somewhat difficult to fluidize. The final product also contains a relatively high level of fines, ie, the particles have a particle size of 125μ. Additionally, methods used to produce catalyst precursor compositions such as those described in prior U.S. patent applications include forming a precursor by dissolving a titanium compound and a magnesium compound in an electron donor compound. Including. The precursor composition is then generally isolated by crystallization or precipitation with a _C5 - _C8 aliphatic or aromatic hydrocarbon. However, these isolation techniques result in non-uniform polymer particle growth and give acicular polymer products. “Impregnated polymerization catalyst,” by G.L. Goeke et al.
Filed March 31, 1978 entitled "Process for the Preparation and Use thereof for Ethylene Copolymerization" and
No. 892,322, refiled as Application No. 012720 on February 16, 1979, is approximately
Ethylene copolymers with densities of ~0.94 and melt flow rates of 22 to 32, which give films of relatively high bulk density and good transparency, can be produced under specific active conditions using organoaluminum compounds. ethylene in the presence of a highly active magnesium-titanium composite catalyst impregnated in a porous inert support material _.
It is disclosed that if copolymerized with C ₈ α-olefins, it can be produced by a gas phase process for industrial purposes with relatively high productivity. However, the preparation of impregnated catalyst precursors as taught in US Application No. 892322/012720 is difficult to control, and the support materials used for impregnation are highly variable in composition. If sufficient care is not taken, highly variable catalyst performance can occur. The morphological properties of the polymer appear to depend on the morphological properties of the support used for the catalyst, and total flexibility and control of polymer particle properties is often not possible. Herein, particles having a wide density range of about 0.91 to 0.97, a bulk density of about 18 to 321 b/ft ³ (about 0.29 to 0.51 g/cm ³ ), and a melt flow rate of 22 to 32 and controlled particle shapes and Ethylene polymers having the same dimensions and having a relatively low residual titanium content are obtained by spray drying a magnesium-titanium-containing precursor composition from a slurry or solution in an electron donor compound and spray drying the magnesium-titanium-containing precursor composition as described below. Ethylene is homopolymerized in the presence of a highly active magnesium-titanium composite catalyst prepared by activating the precursor composition with an organoaluminium compound under specific activation conditions or one or more It has been unexpectedly found that if copolymerized with C ₃ -C ₈ α-olefins, they can be produced in a relatively high productivity for industrial purposes by a gas phase process. Yet another object of the present invention is to provide a method for producing a magnesium-titanium-containing catalyst precursor composition of matched particle shape and size. Another object of the present invention is to provide a simplified method for producing a magnesium-titanium-containing catalyst precursor composition. It is also an object of the present invention to provide a free-flowing catalyst precursor composition in spherical shape. Here, the desired ethylene polymers with low melt flow rates, a wide range of density values, relatively high density values, and controlled particle shapes and dimensions can be produced if under certain combination conditions as detailed below. If the monomer charge is polymerized or copolymerized in the presence of certain highly active catalyst compositions prepared from spray-dried precursor compositions, it can be easily achieved with relatively high productivity in low-pressure gas phase reaction processes. It has been found that it can be manufactured. It has also been found that the inclusion of inert fillers in the precursor composition improves the morphological properties of the polymer. Highly active catalyst The compounds used to produce the highly active catalyst used in the present invention include at least one titanium compound, at least one magnesium compound, at least one electron donor compound, and at least one electron donor compound, as described below. It consists of one type of activator compound. _The titanium compound has _{the formula Ti} ( _OR ) _a group hydrocarbon group), and X is Cl, Br, I or a mixture thereof;
a is 0, 1 or 2, b is 1 to 4, and a+b=3 or 4. ] It has the structure. Titanium compounds can be used individually or in combinations thereof, including TiCl ₃ , TiCl ₄ , Ti
( _OCH3 ) _Cl3 ,Ti( _OC6H5 ) _{Cl3 ,} Ti
( _OCOCH3 ) _Cl3 and Ti _{( OCOC6H5} ) _Cl3 . Magnesium compounds have the structure of the formula MgX ₂ where X is Cl, Br or I. Magnesium compounds of this type can be used alone or in combinations thereof and include MgCl ₂ , MgBr ₂ and MgI ₂ . Anhydrous _MgCl2 is a particularly preferred magnesium compound. To prepare the catalysts used in the present invention, about 0.5 to 56 moles, preferably about 1 to 30 moles, of magnesium compound are used per mole of titanium compound. The titanium and magnesium compounds should have a physical form and chemical properties such that they have at least partial solubility in the electron donor compound, as described below. Electron donor compounds include compounds such as aliphatic and aromatic carboxylic acid alkyl esters, aliphatic ethers, cyclic ethers, and aliphatic ketones. Suitable among these electron donor compounds are alkyl esters of _C1 - _C4 saturated aliphatic carboxylic acids; alkyl esters of _C7 - _C8 aromatic carboxylic acids; C2 _{- C3} , preferably _{C3- C4}
Aliphatic ether; C ₃ -C ₄ cyclic ether, preferably C ₄ cyclic mono- or di-ether; C ₃ -
C ₆ , preferably C ₃ to C ₄ aliphatic ketones;
The most preferred of these electron donor compounds are methyl formate, ethyl acetate, butyl acetate, ethyl ether, hexyl ether, tetrahydrofuran, dioxane, acetone and methyl isobutyl ketone. Electron donor compounds can be used individually or in combinations thereof. About 2 to 8.5 mol, preferably about 3 to 8.5 mol per mol of Ti
45 moles of electron donor compound are used. The activator compound _{has the formula Al} ( _R ″) c 0 to 1.5, e is 1 or 0,
e+d+e=3). Activator compounds of this type can be used individually or in combinations thereof, including Al(C ₂ H 5 ) 3 , Al(C 2 H ₅ ) ₃ ,
Al( _C2H5 ) _{2Cl ,} Al ₍ i- _C4H9 ) ₃ , _Al2
( _{C2H5 )3Cl3 ,} Al ₍ i- _C4H9 ) _2H , _{Al ( C6H13} ) ₃ ,
Includes Al( _C2H5 ) _2H and _{Al ( C2H5} ) ₂ ( _{OC2H5 )} . To activate the catalyst used in this invention, about 10 to 500 moles, preferably about 10 to 200 moles, of activator compound are used per mole of titanium compound. Preparation of the Catalyst The catalyst used in the present invention requires first preparing a precursor composition from a titanium compound, a magnesium compound, an electron donor compound, and a filler, and then spray-drying these compounds as described below for approximately 10 min. ~about 200
It is produced by forming spherical particles with an average particle size of μ. The spherical particles are then treated with an activator compound as described below. The first precursor composition is produced by dissolving a titanium compound and excess magnesium compound (1Mg/Ti56) in an electron donor compound at a temperature of about 20°C to the boiling point of the electron donor compound. . The titanium compound can be added to the electron donor compound before, after, or simultaneously with the addition of the magnesium compound. Total or partial dissolution of the titanium and magnesium compounds can be promoted by stirring and, in some cases, by refluxing the two compounds in an electron donor compound. The electron donor compound is slurried, for example, with an inert filler such as magnesium chloride and/or silica in a separate vessel at a temperature up to the boiling point of the electron donor compound. This slurry or solution can then be added to the Mg/Ti composite solution before or after cooling. The final slurry thus produced can optionally be heated to the boiling point of the electron donor compound before spray drying. The precursor slurry is spray dried at an inlet nitrogen drying gas temperature ranging above the boiling point of the electron donor to about 150°C. Other factors controlled in this process are the vapor pressure of the solvent; the volumetric flow rate of the drying gas is controlled to be significantly greater than the volumetric flow rate of the slurry/solution. Atomization of the slurry can be accomplished with an atomizer pressure of 1 to 200 psig (0.07 to 14 Kg/cm ² G) by a spray nozzle or centrifugal high speed disc atomizer. Fillers added to the solution before spray drying can be any organic or inorganic compound that is inert towards the titanium compound and the final active catalyst, such as silicon dioxide (e.g. fumed silica), titanium dioxide, polystyrene, rubber modifiers. polystyrene, magnesium chloride and calcium carbonate. These fillers can be used individually or in combinations thereof. The amount of filler that may be present in the precursor composition is
From about 10% to about 95% by weight, based on the total weight of the precursor composition. The insoluble filler has an average particle size on the order of about 50μ. When prepared as described above, the precursor composition has the formula MgmTi ₁ (OR) _o X _p [ED] _q [filler] _r [where ED is an electron donor compound and R is
_C1 - _C14 aliphatic or aromatic hydrocarbon group or
COR' (where R' is a _C1-14 aliphatic or _aromatic hydrocarbon group), X is Cl, Br, I or a mixture thereof, and the filler is an inert filler compound; Based on the total weight of the composition, m is from 0.5 to 56, preferably from 1.5 to 5.0, n is from 0.1 to 2, p is from 2 to 116, preferably from 6 to 14, and q is from 2 to 85, preferably from 4 to 11, and r has a value such that the % filler is from about 10 to about 95% by weight. Activation of the Spray-Dried Precursor Composition In order to be used in the method of the present invention, the spray-dried precursor composition must be fully or completely activated, i.e. it must have a sufficient amount of active The Ti atoms in the precursor composition must be converted to an active state by treatment with an agent compound. Activation methods that can be used in this regard are described below. Method A (Total Activation in the Reactor) The spray-dried precursor composition can be fully activated in the polymerization reactor. In this step, the activator compound and the spray-dried precursor composition are preferably fed to the reactor via separate feed lines. The activator compound can be sprayed into the reactor in neat form or as a solution thereof in a hydrocarbon solvent such as isopentane, hexane or mineral oil. This solution usually contains about 2-30% by weight of activator compound. The activator compound has a total Al/Ti molar ratio of 10 to
500, preferably about 10-200. The activator compound added to the reactor reacts with and activates the titanium compound in the reactor. Method B (Two-Step Activation Method) Activation of the spray-dried precursor composition can also be carried out in two steps. In the first step, the spray-dried precursor composition is prepared with an active Wu compound/Ti molar ratio of about >0 to
Partial activation is achieved by reaction with an amount of activator compound sufficient to provide a partially activated precursor composition of 10:1, preferably about 4 to 8:1. The first stage of these two-stage activations can be carried out outside the reactor. To render the partially activated precursor composition active for ethylene polymerization purposes,
An activator compound is added to the polymerization reactor to complete activation of the precursor composition in the reactor. The additional activator compound and partially activated or unactivated precursor composition are preferably fed to the reactor via separate feed lines. The activator compound can be sprayed into the reactor in neat form or as a solution in a hydrocarbon solvent such as isopentane, hexane or mineral oil.
This solution usually contains about 2-30% by weight of activator compound. In the reactor, the activator compound is
With respect to the amounts of active compound and titanium compound provided with the partially activated and spray-dried precursor composition, reacting in amounts such that the total Al/Ti molar ratio is between 10 and 500, preferably between about 10 and 200. added to the bowl. The activator compound added to the reactor reacts with the titanium compound in the reactor to activate it or complete its activation. For example, in a continuous gas phase process, such as the fluidized bed process described below, separate portions of the spray-dried or partially activated precursor composition are combined into Continuously feeding the reactor with discrete portions of the activator compound necessary to activate or complete the activation, replenishing the active catalyst sites consumed during the course of the reaction during successive polymerization steps. do. Polymerization Reaction The polymerization reaction is carried out in a gas phase method such as the fluidized bed method described below and in the presence of moisture, oxygen,
The monomer stream is combined with a catalytically effective amount of the fully activated precursor composition (catalyst) in the substantial absence of catalyst poisons such as CO, _CO2 and acetylene.
by contacting the polymer at a temperature and pressure sufficient to initiate the polymerization reaction. To obtain the desired density range in the copolymer, a sufficient amount of the _C3 coweight is copolymerized with ethylene so that the _C3 - _C8 comonomer in the copolymer is >0-10
It is necessary to bring it to the level of mol %. The amount of comonomer required to achieve this result is
Depends on the particular coweight used. The amounts (in moles) of various comonomers to be copolymerized with ethylene to provide a polymer having the desired density range at any given melt index are listed below. This table also indicates the relative molar concentrations of comonomer to ethylene present in the monomer cycle gas stream under reaction equilibrium conditions in the reactor.

[Table] A fluidized bed reaction system that can be used to carry out the method of the present invention is shown in FIG. Referring to FIG. 1, a reactor 1 consists of a reaction zone 2 and a rate reduction zone 3. Reaction zone 2 consists of a bed of growing polymer particles, a bed of formed polymer particles and a small amount of catalyst particles, which continuously supply a polymerizable and controllable gas component as a make-up recycle gas to the reaction zone. It is fluidized by flowing it with water. To maintain an active fluidized bed, the mass gas flow rate through the bed must be higher than the minimum flow required for fluidization, preferably from about 1.5 to about 10 times Gmf, and more preferably from about 1.5 to about 10 times Gmf.
It is about 3 to about 6 times that of Gmf is accepted as an abbreviation for the minimum mass gas flow required to obtain fluidization [C.Y. Wen and Y.H.T.U., "Mechanics of Fluidization", Chemical engineering
Progress Symposium Series Volume 62, No.
pp. 100-111 (1966)]. It is essential that the bed always contain particles to prevent the formation of local "hot spots" and to encapsulate and distribute the particulate catalyst throughout the reaction zone. Upon start-up, the reactor is typically charged with a substrate of particulate polymer particles before gas flow is started. The particles can be identical or different in nature to the polymer to be produced. If different, they are taken off as the first product together with the desired product polymer particles. Eventually, a fluidized bed of desired polymer particles replaces the starting bed. Spray-dried or partially activated precursor compositions used in a fluidized bed are preferably dried under a blanket of gas inert to the storage material, such as nitrogen or argon. It is stored for use in storage tank 4. Fluidization is accomplished by high velocity gas circulation to and through the bed, typically on the order of about 50 times the make-up gas feed rate. A fluidized bed has the general appearance of a concentration of particles that may exist in a possible free vortex flow, such as caused by the permeation of gas through the bed. The pressure drop across the bed is equal to or slightly greater than the mass of the bed divided by the cross-sectional area. This therefore depends on the reactor geometry. Makeup gas is supplied to the bed at a rate equal to the rate at which the particulate polymer composition is removed. The composition of the makeup gas is measured by a gas analyzer 5 located above the bed. The gas analyzer measures the composition of the gas being circulated so that the makeup gas composition is adjusted to maintain a near steady state gas composition within the reaction zone. In order to ensure complete fluidization, the cycle gas and, if necessary, a portion of the make-up gas are returned to the reactor via the gas circuit 6 at a point 7 below the bed. A gas distribution plate 8 is present above the return point to help fluidize the bed. The part of the gas stream that does not react in the bed forms the recycle gas, which is preferably a velocity reduction zone 3 above the bed.
The embedded particles are then removed from the polymerization zone by giving them an opportunity to fall back to the bed. The circulating gas is then compressed by a compressor 9,
It is then passed through a heat exchanger 10 where the heat of reaction is extracted, and then returned to the bed. The temperature of the bed is controlled at a nearly constant temperature under steady-state conditions by constantly removing the heat of reaction. There appears to be no appreciable temperature gradient within the top of the bed. A temperature gradient exists between the temperature of the inlet gas and the rest of the bed in a 6-12 inch (15-30 cm) layer at the bottom of the bed. The recycle is then returned to the reactor at the bottom 7 and through the distribution plate 8 back to the fluidized bed. Compressor 9 can also be installed downstream of heat exchanger 10. The distribution plate 8 plays an important role in the operation of the reactor. The fluidized bed contains growing and generated particulate polymeric particles as well as catalyst particles. While the polymer particles are hot and possibly active, they must be prevented from settling. This is because if a stationary substance is present, the active catalyst contained therein will continue to react and cause fusion. Therefore, it is important to diffuse the circulating gas through the bed at a sufficient rate to maintain fluidization throughout the bed. The distribution plate 8 serves this purpose and can be a screen, a slotted plate, a perforated plate, a bell-shaped plate, etc. All members of the plate may be fixed or the plate may be movable of the type disclosed in US Pat. No. 3,298,792. Whatever its design, it serves to diffuse circulating gas through the particles at the bottom of the bed to keep the bed fluid and to support a stationary bed of resin particles when the reactor is not in operation. must be done. The movable member of the plate may also be used to remove any polymer particles trapped in or on the plate. Hydrogen can be used as a chain transfer agent in the polymerization reaction of the present invention. The hydrogen/ethylene ratio used will vary from about 0 to about 2 moles of hydrogen per mole of monomer in the gas stream. Any gas that is inert to the catalyst and reactants can also be present in the gas stream. The activator compound is preferably added to the reaction system downstream of heat exchanger 10. The active agent compound can therefore be fed from the dispenser 11 via the line 12 into the gas circulation. Together with the catalyst of the present invention, structural formula Zn(Ra)(Rb) [wherein Ra and Rb are the same or different C ₁ -
C ₁₄ aliphatic or aromatic hydrocarbon group] can be used together with hydrogen as a molecular weight regulator or chain transfer agent, i.e. to increase the melt index value of the copolymer produced. I can do it. Titanium compound (Ti
About 0 to 100 moles per mole (as Zn) of the Zn compound (as Zn) will be used in the gas stream in the reactor. The zinc compound is preferably dissolved in a dilute solution in a hydrocarbon solvent (2 to
30% by weight) or adsorbed on a solid diluent such as silica in an amount of about 10 to 50% by weight. These compositions have a tendency to spontaneously ignite. Zinc compounds can be used alone or in dispenser 11
It may also be used with an optional additional portion of active compound added to the reactor from a feeder (not shown) which may be located adjacent to the reactor. It is important that the fluidized bed reactor be operated at a temperature below the sintering temperature of the polymer particles to ensure that sintering does not occur. To suitably produce ethylene homopolymers and copolymers using the ethylene polymerization catalysts of the present invention, operating temperatures of about 30 DEG to 115 DEG C. are normally used. Approximately 0.91 using a temperature of approximately 75-95℃
Produce products with a density of ~0.92 and also approximately 50
using a temperature of ~100°C to produce a product having a density of about 0.91 to 0.92; and using a temperature of about 80 to 100°C to produce a product having a density of about >0.92 to 0.94; A temperature of about 90-115°C is also used to produce a product having a density of about >00.94-0.97. Fluidized bed reactors operate at pressures up to about 1000 psi (70 Kg/cm ² ), preferably about 150 to 350 psi (11
~25 Kg/ ^cm2 ), and can also be operated at higher pressures in the range as preferred for heat transfer. This is because an increase in pressure increases the unit volume heat capacity of the gas. The spray-dried precursor or partially activated spray-dried precursor composition is injected into the bed at a point 13 above the distribution plate 8 at a rate equal to the consumption rate. Preferably, the catalyst is injected at a point in the bed where good mixing of the polymer particles occurs. The possibility of injecting the catalyst above the distribution plate is an important feature of the invention. Since the catalyst used in the embodiments of the present invention is highly active, injecting a sufficiently activated catalyst into the lower zone of the distribution plate will initiate polymerization there, eventually leading to blockage of the distribution plate. . In contrast, injection into an active bed aids in catalyst distribution throughout the bed and tends to eliminate the formation of localized spots of high catalyst concentration such as the formation of "hot spots." Injection into the reactor above the bed causes excess catalyst to be carried away into the circulation path, in which polymerization can begin and eventually lead to blockage of the path and the heat exchanger. For example, using a gas that is inert to the catalyst, such as nitrogen or argon, the partially reduced or fully reduced precursor composition and the required activator compound or non-gas chain transfer agent are introduced into the bed. Bring it in. The production rate of the bed is controlled by the rate of catalyst injection. The production rate is increased simply by increasing the rate of catalyst injection and decreased by decreasing the rate of catalyst injection. Since any change in catalyst injection rate changes the rate of heat generation of reaction, the temperature of the circulating gas entering the reactor is adjusted upward or downward to accommodate the change in the rate of heat generation. This ensures the maintenance of an approximately constant temperature in the bed. Complete equipment, both in the fluidized bed and in the circulating gas cooling system, is of course necessary to detect any temperature changes in the bed so that the operator can make appropriate adjustments to the temperature of the circulating gas. . Under a given set of operating conditions, the fluidized bed:
A substantially constant height is maintained by withdrawing a portion of the bed as product at a rate equal to the rate of production of particulate polymer product. Since the rate of heat release is directly related to product formation, measurement of the temperature rise of the gas across the reactor (difference between inlet and outlet gas temperatures) is a determinant of the rate of particulate polymer formation at a constant gas velocity. It is. The particulate polymer product is preferably withdrawn continuously at a location 14 at or adjacent to the distribution plate 8 and in suspension with a portion of the gas stream being exhausted. This is because when the particles reach their final collection zone, they settle to minimize further polymerization and sintering. Suspension gas can also be used to transfer the product of one reactor to another. The particulate polymer product is conveniently and preferably withdrawn by the sequential actuation of a pair of timing valves 15 and 16 defining a separation zone 17. While valve 16 is closed, valve 15 is open to provide a plug flow of gas and product between zone 17 and valve 15.
then the valve 15 is closed. Valve 16 is then opened to supply product to the external recovery zone. Valve 16 is then closed awaiting the next product recovery operation. The exhaust gas containing unreacted monomers is recovered from zone 17 via line 18 and recompressed in compressor 19, either directly or via purifier 20 and via line 21 to circulation compressor 9. It can be returned to the gas circulation path 6 at an upstream location. Finally, the fluidized bed reactor is equipped with an adequate exhaust system to evacuate the bed during startup and shutdown. The reactor does not require the use of stirring means and/or wall scraping means, the circulating gas path 6 and the equipment therebetween (compressor 9, heat exchanger 10) should have a smooth surface finish; Unnecessary obstructions should be removed so as not to impede the flow of circulating gas. The highly active spray-dried catalyst system of the present invention has a
It is believed to produce a fluidized bed product having an average particle size of 2550μ, preferably from about 250μ to about 1525μ. The gaseous monomer feed stream, with or without an inert gaseous diluent, has an air yield of about 2-10 lb/hr/ ^ft3 bed volume (about 32-160 Kg/hr/ ^m3 bed volume). is supplied to the reactor. The term virgin resin or polymer as used herein refers to the polymer in particulate form as it is recovered from the polymerization reactor. The following examples are illustrative of the method of the invention and are not intended as limitations on the scope of the invention. The properties of the polymers produced in the Examples were measured by the following test methods. Density: For materials with density <0.940, use ASTM-1505 method and black 100
Condition for 1 hour at °C to approach equilibrium crystallinity. For materials with a density of 0.940, a modified method is used in which the test black is conditioned at 120° C. for 1 hour to approach equilibrium crystallinity and then rapidly cooled to room temperature. All density values are reported as g/cm ³ . All density measurements are performed in density gradient columns. Melt index (MI): ASTM D-1238
- Condition E - Measured at 1190℃ - g per 10 minutes
Recorded as a number. Flow rate (HLMI): ASTM D-1238-Condition F-
Measured at 10 times the weight used in the melt index test above. Melt Flow Ratio (MFR): Flow Rate/Melt Index Productivity: Ash a sample of the resin product and measure the weight percent ash. Since the ash consists essentially of catalyst, the productivity depends on the amount of titanium metal consumed.
is the number of pounds of polymer produced per 11b. The amounts of Ti, Mg and halogens in the ash are determined by elemental analysis. Values are recorded as ppm of titanium metal. Bulk Density: The resin is poured into a 100 ml graduated cylinder through a 3/8 inch (9.5 mm) diameter bowl without shaking the cylinder and the weight is determined by difference.
Record the value as 1b/ ^ft3 . Average Particle Size: This is calculated from sieve analysis data measured using 500 g of sample according to ASTM D-1921 Method A. The calculation is based on the weight of the fraction remaining on the sieve. Molecular weight distribution (Mw/Mn): Gel permeation chromatography. For resins with density <0.94: Styrogel filling: (pore size order is
10 ⁷ , 10 ⁴ , 10 ³ , 60 Å). Solvent temperature is 117℃
perchlorethylene. For resin with density of 0.94: Styrogen filling:
(The pore size order is 10 ⁷ , 10 ⁶ , 10 ⁵ , 10 ⁴ , 60 Å). The solvent is orthodichlorobenzene at 135°C. Detection for all resins: 3.45μ
Infrared analysis. n-hexane extract: FDA approved for use in polyethylene films intended for food contact applications
test. 1.5 mil (0.038mm) gauge film
200in ² (1290cm ² ) sample into 1in x 6in (2.5cm x 15
cm) and weigh to an accuracy of 0.1 mg. Place these pieces in a container with 300ml
Extract with n-hexane at 50±1°C for 2 hours. The extract is then decanted into a tared culture dish. After drying the extract in a vacuum dessicator, weigh the culture dish to an accuracy of 0.1 mg. The extractables, standardized with respect to the original sample weight, are then reported as parts by weight of n-hexane extract. Unsaturation: Infrared spectrophotometer (Birkin Elmer model 21). A press made from 25 mil (0.64 mm) thick resin is used as the test sample. For trans-vinylidene unsaturation, absorbance is
For terminal vinyl unsaturation at 10.35μ
Measure at 11.0μ and for side chain vinylidene unsaturation at 11.25μ. The absorbance per mil of press thickness is directly proportional to the product of unsaturation concentration and absorption coefficient. The extinction coefficient is R.
Adopted from the literature value of J. Dekotsuk et al., Journal of Polymer Science, Part B, 2, p. 333 (1964). Preparation of spray-dried precursor 1.0 in 5 flasks equipped with a mechanical stirrer
of tetrahydrofuran (THF) and 71.0 g of anhydrous magnesium chloride was slowly added to the THF while stirring under a nitrogen atmosphere. The temperature of this exothermic reaction was controlled by the rate of addition of magnesium chloride and the use of a water bath. After the magnesium chloride addition was complete, 90.0 g of fumed silica was slowly added to the slurry. After the fumed silica addition was complete, the slurry was refluxed for 2-6 hours. (Fused silica has a particle size in the range of 0.007 to 0.05 microns and is
- SIL) is commercially available as fumed silica by Kabotu. It has a _SiO2 content of >99.8%). 13.4 g of anhydrous MgCl ₂ in 0.8 THF under nitrogen in two separate flasks equipped with a mechanical stirrer.
mixed with. The mixture was stirred at room temperature (~25 °C),
During that time, 8.9 ml of TiCl ₄ was added dropwise over 1/2 hour. After the TiCl ₄ addition was complete, the contents of the flask were heated to reflux for about 1/2 to 1 hour to dissolve the solids. The system was allowed to cool to room temperature while stirring. The contents of this flask were then slowly added to the contents of the previously prepared slurry of magnesium chloride. The contents of the vessel were refluxed with stirring for about 1 hour, then cooled to room temperature with stirring. The final product was a yellow-green slurry that remained suspended for approximately 1 hour before separation. This slurry/suspension was dried at 10 psi (0.7 Kg/cm ² ) Spray-dried under a spray pressure of 112°C and a drying nitrogen inlet gas temperature of 112°C. The spherical catalyst particles collected in the cyclone had an average particle diameter of about 25μ as determined by optical micrographs. Activation Step The precursor composition produced above was activated in various ways. Method A (Overall Activation in the Reactor) An activator compound was fed to the polymerization reactor for the purpose of activating the precursor composition. This was fed into the reactor as a dilute solution in a hydrocarbon solvent such as isopetane. This diluted solution is about 2 to
Contained 30% by weight activator compound. The activator compound is present in the reactor at a concentration of about 10 to
500, preferably at a level of 10-200, to the polymerization reactor. Method B (Two-Step Activation Method) The precursor composition produced as described above is mixed with the precursor composition and an activator compound with a sufficient amount of an anhydrous aliphatic hydrocarbon diluent such as isopentane. It was activated by adding a slurry system to the tank. The activator compound and the precursor compound are 0 to
Amounts were used to give a partially activated precursor composition having an Al/Ti ratio of 10:1, preferably 4 to 8:1. The contents of the slurry system were then thoroughly mixed at room temperature and atmospheric pressure for about 1/4 to 1/2 hour. The resulting slurry is then heated to atmospheric pressure and 65°C under a purge of dry inert gas such as nitrogen or argon.
The hydrocarbon diluent was removed by drying at a temperature of ±10°C. The resulting composition was in the form of a partially activated, spray-dried precursor. Additional activator compound is fed to the polymerization reactor for the purpose of completing the activation of a partially activated precursor composition or for the purpose of fully activating an unactivated precursor composition in one step. If so, it was fed into the reactor as a dilute solution in a hydrocarbon solvent such as isopentane. These dilutions contained approximately 2-30% by weight of activator compound. The activator compound is about 10 to 500, preferably 10 to 500
was added to the polymerization reactor to maintain an Al/Ti ratio in the reactor at a level of 200. Examples 1-9 In this series of examples, both Method A (for Examples 1-3 and 5-7) and Method B (for Examples 4, 8, and 9) were produced as described above. Homopolymerization of ethylene (Examples 2, 8 and) and copolymerization with butene-1 (Examples 1 and 3-7) using catalysts activated by was manufactured. After each of the polymerization reactions reaches equilibrium, the first
300psia (22Kg/ ^cm2) at the temperature shown in the table.
A) Fluidized bed reactor system at a space-time yield of about 3 to 71 b/hr/ft ³ of bed space (about 48 to 112 Kg/hr/m ³ of bed space) at a pressure of A) and a gas velocity of about 3 to 6 times Gmf. So＞
This was done continuously for one hour. The reactor system was as described above in FIG. This is the height
It had a lower part 10 ft (3 m) and 13 1/2 in (34.3 cm) inside diameter and an upper part 16 ft (4.9 m) high and 23 1/2 in inside diameter. The following table for Examples 1-9 lists the various operating _{conditions used in these Examples: weight percent of [MgCl] 2.5 [} TiCl ₄ ] [THF] ₇ ; filler type and amount; partial activation. of the precursor composition
Al/Ti ratio; polymerization temperature; H ₂ /C ₂ molar ratio; comonomer C ₄ /C ₂ molar ratio in reactor; and titanium metal 1 lb.
Catalyst productivity (recorded as ppm of titanium metal) is shown in lbs of polymer produced per lb of polymer. The table below shows the properties of the granular virgin resins made in Examples 1-9, namely density, melt index (MI), melt flow rate (MFR), bulk density, average particle size and extremely small particle size (<74μ). ) content (weight%).

【table】

【table】

TABLE The data in the table shows that spray drying the precursor composition without filler (Example 7) results in a lower bulk density. Furthermore, the polymer particles produced in Example 7 were fibrous materials having a linear consistency.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a gas phase fluidized bed reactor system in which the catalyst system of the present invention can be used. DESCRIPTION OF SYMBOLS 1...Reactor, 2...Reaction zone, 3...Velocity reduction zone, 4...Storage tank, 5...Gas analyzer, 6...
...Gas circulation path, 8...Distribution plate, 9...Compressor, 1
0... Heat exchanger, 11... Dispenser, 1
5, 16... Timing valve, 17... Separation zone.

Claims (1)

[Claims] 1A A spherical precursor composition of the following formula Mg _n Ti ₁ (OR) _o X _p [ED] _q [filler] _r [wherein R is a C ₁ to C ₁₄ aliphatic or aromatic group hydrocarbon group or COR′ (where R′ is C ₁ to _{C 14}
an aliphatic or aromatic hydrocarbon group), X is Cl, Br, I or a mixture thereof, ED is an electron donor compound, and the filler is an inert filler compound; m is 0.5 to 56, n is 0.1 or 2, p is 2 to 116, q is 2 to 85, and r is the percent filler based on the total weight of the composition. Based on weight approx.
at least one magnesium compound, at least one titanium compound, and at least one filler compound in at least one electron donor compound; forming a slurry or solution of the precursor composition in the electron donor compound, and spray drying the slurry or solution by atomization to form particles of about 10 to about 200 microns. forming a spherical precursor composition by forming spherical particles of the precursor composition having dimensions, wherein the magnesium compound has the formula MgX ₂ (wherein
X is as described above), and the titanium compound has the formula Ti(OR) _a X _b [wherein,
a is 0.1 or 2, b is 1 to 4,
a+b=3 or 4, and R and X are as described above], and the electron donor compound is a liquid organic compound that can dissolve the magnesium compound and the titanium compound, B selected from the group consisting of alkyl esters, aliphatic ethers, cyclic ethers and aliphatic ketones of group and aromatic carboxylic acids;
by partial activation with >0 to 10 moles of activator compound per mole of Ti or 10 to 500 moles of activator compound per mole of Ti in this precursor composition.
Activation is achieved by complete activation with molar of an activator compound, said activator compound having the formula A1(R') _e X' _d H _e where X' is C1 or OR and R'' and R are the same or different _C1 - _C14 saturated hydrocarbon groups, d is 0-1.5, e is 1 or 0 and e+d+e=3], and said activation is based on said precursor composition. A catalyst composition for ethylene polymerization produced by: 2. A catalyst composition according to claim 1, wherein the magpasium compound comprises MgC1 _2. 3. An electron donor compound. 4. The catalyst composition according to claim 2, wherein the electron donor compound is made of at least one ether. 4. The catalyst composition according to claim 3, wherein the electron donor compound is tetrahydrofuran. 5. The titanium compound is composed of _TiC14 . A catalyst composition according to claim 4.