CN1418894A

CN1418894A - Polyolefine catalyst, its making method, using method, and polymer made from said catalyst

Info

Publication number: CN1418894A
Application number: CN 01137457
Authority: CN
Inventors: S·D·格雷; T·J·科菲
Original assignee: Fina Technology Inc
Current assignee: Fina Technology Inc
Priority date: 2001-11-14
Filing date: 2001-11-14
Publication date: 2003-05-21
Anticipated expiration: 2021-11-14
Also published as: CN1272349C

Abstract

The heat treatment of preactivated Zieglar-Natta catalyst can control molecular weight distribution of polyolefin produced by said catalyst, at the same time said catalyst can retain high activity and good villus state still.

Description

Polyolefin catalyst, method of making, method of using, and polymers made therefrom

See related application

This application is a continuation-in-part application of U.S. patent application entitled "Ziegler-Natta catalyst for olefin polymerization" filed on 28/1 1997, serial No. 08/789,862, which is incorporated herein by reference.

Background

The present invention relates to a catalyst, a method for producing the catalyst, a method for using the catalyst, a polymerization method, and a polymer produced by the catalyst. In another aspect, the present invention relates to a polyolefin catalyst, a method of making the catalyst, a method of using the catalyst, a polymerization reaction of a polyolefin, and a polyolefin. In yet another aspect, the present invention also relates to Ziegler-Natta catalysts, methods of making the catalysts, methods of using the catalysts, polymerization of polyolefins, and polyolefins.

Background

Ziegler-type polyolefin catalysts, their usual production methods and their subsequent use methods have been widely known in the polymerization field since the beginning of the 50 th century.

However, although not a few are known for ziegler-type catalysts, there is a constant search for methods to improve their polymer yield, catalyst life, catalyst activity, and their ability to make polyolefins having certain properties.

U.S. patent 4,255,544 issued on 10/3 1981 to Kimura et al discloses a process for the polymerization of ethylene using a catalyst comprising: (A) a reaction product of a magnesium compound and a titanium halide, (B) an organoaluminum compound wherein component A is obtained by reacting a magnesium dialkoxide with a halogen-containing silicon compound and an alcohol to obtain a solid substance, and then reacting the solid substance with a titanium halide in the presence of a silicon compound having an alkoxy group.

Published in 1990, 4/3, Job et al, U.S. Pat. No. 4,914,069, discloses a process for the preparation of an olefin polymer catalyst component having improved activity and selectivity, which process comprises: (a) halogenating a magnesium compound containing at least one aryloxy, alkyl, or carbonate or alkoxy group with a first halide of tetravalent titanium and a first electron donor; (b) contacting the resulting product with a second halide of tetravalent titanium; (c) the resulting treated halogenated product is washed with an inert hydrocarbon liquid. In this process, a second electron donor is used in step (a) or (b), and the product of step (b) is contacted with a third halide of tetravalent titanium at a temperature of 40-140 ℃ in step (b2), followed by washing the treated product in step (c).

U.S. patent 5,155,187 issued on 10/13 of 1992 to Shelly discloses a polymerization process using a catalyst which is generally the reaction product of: a silicon-containing compound, a dialkyl magnesium, an alcohol, a halide-containing metal compound, an aluminum alkoxide, and a second halide-containing metal compound.

U.S. patent 5,610,246 issued to Buehler et al, 3/11/1997, discloses a process for the polymerization of propylene using a silica supported catalyst. The catalyst comprises the product resulting from contacting silica with, in any order: (1) at least one hydrocarbon-soluble magnesium-containing compound; (2) a first modified compound selected from the group consisting of: silicon halides, boron halides, aluminum halides, and mixtures thereof, followed by a specially modified second compound.

Us patent 5,631,334 issued on 20/5/1997 in Zandona discloses a process for the manufacture of a catalyst solid for the (co) polymerization of at least one olefin, which comprises precipitating magnesium together with at least one transition metal.

However, despite the advances in the art, these prior art do not disclose or suggest a heat treatment to pre-activate a polyolefin catalyst.

In addition, these prior art references also do not disclose or suggest any effect of heat treatment of the preactivated polyolefin catalyst on the polymer molecular weight distribution ("MWD").

Accordingly, there is a need in the art for polyolefin catalysts.

There is also a need in the art for a method of making a polyolefin catalyst.

There is also a need in the art for a process for the polymerization of olefins.

There is also a need in the art for polyolefins having various molecular weight distributions.

There is also a need in the art for polyolefin catalysts that facilitate the production of polyolefins of various molecular weight distributions, which catalysts also have high activity and good fluff morphology.

There is also a need in the art for a method of producing a molecular weight distribution in a polyolefin using a heat treated preactivated polyolefin catalyst.

These and other needs in the art will become apparent to those skilled in the art from this specification, including the drawings and claims hereof.

Summary of The Invention

It is an object of the present invention to provide a polyolefin catalyst.

It is another object of the present invention to provide a method for producing the polyolefin catalyst.

It is another object of the present invention to provide a process for the polymerization of olefins.

It is another object of the present invention to provide polyolefins of various molecular weight distributions.

It is another object of the present invention to provide a polyolefin catalyst which facilitates the production of polyolefins of various molecular weight distributions, and which also has high activity and excellent fluff morphology.

It is yet another object of the present invention to provide a process for producing a molecular weight distribution in a polyolefin using a heat-treated preactivated polyolefin catalyst.

According to one embodiment of the present invention, a polyolefin catalyst is provided. The catalyst is prepared by a method comprising the following steps: a) synthesis of a magnesium dialkyl of the formula Mg (OR')₂Wherein R, R 'and R' are each a hydrocarbyl or substituted hydrocarbyl group containing 1 to 20 carbon atoms, and two or more of R, R ', R' may be the same or different; b) contacting a magnesium dialkoxide compound with a weak halogenating agent capable of replacing an alkoxy group with a halogen to form a reaction product "A"; c) contacting the reaction product "a" with a first halogenating/titanating agent to form a reaction product "B"; d) contacting the reaction product "B" with a second stronger halogenating/titanating agent to form a reaction product "C"; e) contacting the reaction product "C" with an organoaluminum preactivating agent to form a preactivated catalyst; f) the pre-activated catalyst is heated. In step f), the pre-activated catalyst is heated at a temperature in the range of about 90 to about 150 ℃ for a time period in the range of about 30 minutes to about 24 hours.

In another embodiment of the present invention, a polyolefin polymer is provided, which polymer is made by a process comprising contacting one or more α -olefin monomers with each other under polymerization conditions in the presence of a catalyst of the present invention.

Another embodiment of the present invention provides a catalyst system comprising the polyolefin catalyst of the present invention and an inert support. Typically the inert carrier is a magnesium compound.

Another embodiment of the present invention provides a method for producing the catalyst. The method generally comprises the steps of: a) from dialkylmagnesium of the formula MgRR 'and of the formula R' OHAlcohol reaction to synthesize the general formula Mg (OR')₂Wherein R, R 'and R "are each a hydrocarbyl or substituted hydrocarbyl group containing 1 to 20 carbon atoms, and two or more of R, R', R" may be the same or different; b) contacting a magnesium dialkoxide compound with a weak halogenating agent capable of replacing an alkoxy group with a halogen to form a reaction product "A"; c) contacting the reaction product "a" with a first halogenating/titanating agent to form a reaction product "B"; d) contacting reaction product "B" with a stronger second halogenating/titanating agent to form a reaction product"C"; e) contacting the reaction product "C" with an organoaluminum preactivating agent to form a preactivated catalyst; f) the pre-activated catalyst is heated. In step f), the pre-activated catalyst is heated at a temperature in the range of about 90 to about 150 ℃ for a time period in the range of about 30 minutes to about 24 hours.

In yet another embodiment of the present invention, there is provided a process for the polymerization of α -olefins, the process generally comprising the steps of a) contacting one OR more α -olefins with each other under polymerization conditions in the presence of a catalyst, b) withdrawing a polyolefin polymer, the monomer preferably being an ethylene monomer and the polymer preferably being polyethylene₂Wherein R, R 'and R' are each a hydrocarbyl or substituted hydrocarbyl group containing 1 to 20 carbon atoms, and two or more of R, R ', R' may be the same or different; ii) contacting the magnesium dialkyl compound with a weak halogenating agent capable of replacing an alkoxy group with a halogen to form a reaction product "A"; iii) contacting the reaction product "A" with a first halogenating/titanating agent to form a reaction product "B"; iv) contacting reaction product "B" with a second stronger halogenating/titanating agent to form reaction product "C"; v) contacting the reaction product "C" with an organoaluminum preactivating agent to form a preactivated catalyst; vi) heating the pre-activated catalyst.

These and other objects will be apparent to those skilled in the art from this specification, including its drawings and claims.

Drawings

FIG. 1 is a bar graph showing the effect of heat treatment on the intrinsic molecular weight distribution of the catalyst.

Detailed Description

The method for producing the catalyst component of the present invention generally comprises the steps of: forming a dialkoxide of a metal from a metal dialkyl and an alcohol, halogenating the metal dialkoxide, forming a catalyst component in one or more steps using a halogenation/titanation agent, treating the catalyst component with a preactivating agent such as an organoaluminum to form a preactivated catalyst, and heat treating the preactivated catalyst.

The mechanism proposed by the process of the invention is generally as follows:

1.MRR′+2R″OH→M(OR″)₂；

2.M(OR″)₂+ClAR′″_x→″A″；

3.″A″+TlCl₄/Ti(OR″″)₄→″B″；

4.″B″+TiCl₄→ "C" (catalyst component);

5. "C" + TEAL → preactivated catalyst;

6. heat treatment of preactivated catalysts

In the above formula, M may be any suitable metal, preferably group IIA, most preferably Mg. In the above formula, R, R ', R' and R 'are each hydrocarbyl, or substituted hydrocarbyl moieties, and R' contain 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 to 4 carbon atoms. R "typically contains 3 to 20 carbon atoms, R'" typically contains 2 to 6 carbon atoms, R "" typically contains 2 to 6 carbon atoms, and is typically butyl. Any combination of two or more of R, R ', R' may be the same, or the R groups may be different.

ClAR' ″ in the above formula_xIn which A is preferably a non-reducing oxophilic compound capable of replacing an alkoxy group with a chloride ion, R' "is preferably an alkyl group, and x is the valence of A minus 1. Examples of a include titanium, silicon, aluminum carbon, tin and germanium, with titanium being most preferred and x being most preferred 3. Examples of R' "include methyl, ethyl, propyl, isopropyl and the like containing 2 to 6 carbon atoms.

When the precise composition of product "a" is unknown, it is believed to contain a partially chlorinated metal compound, an example of which is ClMg (OR "). The first halogenation/titanation step produces a product "B" which is presumably a complex of a chlorinated and partially chlorinated metal with a titanium compound, such as may be obtained from (MCl)₂)y·(TiCl_x(OR)_4-x)_z′And (4) showing. The second chlorination/titanation gives the product "C", which may also be a complex of a chlorinated and partially chlorinated metal with a titanium compound, but, unlike the product "B", may be prepared from (MCl)₂)_y·(TiCl_x(OR)_4-x′)_z′And (4) showing. "product C" is expected to be more chlorinated than "product B". A greater degree of chlorination can produce different complexes of different compounds. While these descriptions of the reaction products now provide the most likely chemical explanations, the invention as recited in the claims is not limited by these theoretical mechanisms.

The metal dialkyl and metal dialkoxides produced suitable for use in the present invention include any metal dialkyl and metal dialkoxides that produce suitable polyolefin catalysts when used in the present invention. Preferred metal dialkoxides and dialkyl metals include metal dialkoxides and metal dialkoxides of group IIA metals. More preferred metal dialkoxides or dialkyl metals are magnesium dialkoxides or magnesium dialkyls.

In an embodiment of the invention, the magnesium dialkyl [ MgRR '] may be any magnesium dialkyl wherein R and R' are as described above. Of course, R and R' may be the same or different. Non-limiting examples of suitable dialkylmagnesium include diethylmagnesium, dipropylmagnesium, dibutylmagnesium, butylethylmagnesium, and the like. Butylethylmagnesium (BEM) is the preferred magnesium dialkyl.

In an embodiment of the invention, the metal dialkoxide is preferably of the formula Mg (OR')₂Wherein R' is a hydrocarbyl or substituted hydrocarbyl group containing 1 to 20 carbon atoms. The dialkoxymagnesium compound is a reaction product of a magnesium compound of the formula MgRR 'and an alcohol of the formula R' OH, wherein R and R 'are alkyl groups containing 1-10 carbon atoms, and may be the same or different, and the alcohol is a straight or branched chain alcohol, and wherein R' isIs an alkyl group having 4 to 20 carbon atoms.

The metal dialkoxide is most preferably soluble and non-reducing. The advantage of the non-reducing compound is that it forms MgCl₂Rather than soluble Ti formed by reduction of compounds such as MgRR⁺³The latter tend to form catalysts having a broad particle size distribution. In addition, Mg (OR')₂Is less reactive than MgRR', chlorination with a weak chlorinating agent, followed by simultaneous chlorination/titanation with a weak agent and a second chlorination/titanation with a stronger agent being a stepwise and sequentially stronger reaction, which results in a more uniform product, i.e. larger catalyst particles and a more uniform catalyst particle size distribution.

Non-limiting examples of preferred types of metal dialkoxides that are suitable for use include dibutoxymagnesium, dipentyloxymeagnesium, dihexyloxymagnesium, bis (2-ethylhexyloxy) magnesium, and any alkoxide suitable to render the system soluble. The most preferred type of metal alkoxide is magnesium bis (2-ethylhexyloxy).

By way of non-limiting example, magnesium dialkoxides, such as magnesium bis (2-ethylhexoxide), can be prepared by reacting an alkyl magnesium compound (MgRR '), such as Butyl Ethyl Magnesium (BEM), with an alcohol (R' OH), such as 2-ethylhexanol, represented by the formula:

in the case of BEM, RH and R' H are respectively butane and ethane. The reaction was carried out at room temperature and the reactants formed a solution. Any two or more of the R groups may be the same, or the R groups may be different from each other.

In embodiments of the invention, any alcohol that produces the desired metal dialkoxide may be used. As a non-limiting example, the alcohol may be any alcohol having the formula R 'OH, wherein R' is an alkyl group having from 4 to 20 carbon atoms. The alcohol may be a linear or branched alcohol. Non-limiting examples of alcohols include butanol, isobutanol, 2-ethylhexanol, and the like. The preferred alcohol is 2-ethylhexanol.

The amount of the alcohol to be added is usually about 0.5 to 4 equivalents (equivalents relative to the total amount of magnesium or metal compound), preferably about 1 to 3 equivalents. Although it is believed that almost any alcohol can be used, it is preferred to use a higher branched alcohol, such as 2-ethyl-1-hexanol. The alcohol used generally contains at least 3 carbon atoms, preferably at least 4, more preferably at least 5, and most preferably at least 6 carbon atoms.

Metal alkyl compounds are highly associated due to electron deficient bonding, which results in highly viscous high molecular weight forms in solution. This high viscosity can be reduced by the addition of an aluminum alkyl, such as triethylaluminum. Aluminum alkyls disrupt the association between individual metal alkyl molecules. The ratio of aluminium alkyl to metal is preferably from 0.001: 1 to 1: 1, more preferably from 0.01 to 0.1: 1, most preferably from 0.03: 1 to 0.05: 1. In addition, electron donors such as ethers, for example, diisoamyl ether (DIAE), may be used to further reduce the viscosity of the metal alkyl. The preferred range of electron donor to metal ratio is from about 0: 1 to about 10: 1, and more preferably from about 0.1: 1 to about 1: 1.

The reagents used in the halogenation step to halogenate the metal alkoxide include any halogenating agent that, when used in the present invention, produces a suitable polyolefin catalyst. The halogenation step is preferably a chlorination step, and the preferred halogenating agent is a chloride.

The preferred chloride halogenating agent ("chlorinating agent") is preferably a monochloride, which only partially chlorinates the dialkoxymagnesium. Preferred chlorinating agents are of the general formula ClAR' ″_xOr ClAOR' ″_xWherein A is a non-reducing oxophilic compound capable of replacing an alkoxy group with a chloride ion, R' ″ is an alkyl group, and x is the valence of A minus 1. Examples of A are titanium, silicon, aluminum, carbon, tin and germanium, most preferablyPreferred are titanium and silicon, where x is 3. Examples of R' "are methyl, ethyl, propyl, isopropyl and the like containing 2 to 6 carbon atoms. An example of a chlorinating agent useful in the present invention is ClTi (O)ⁱPr)3 and ClSi (Me)₃。

Halogenation of the metal alkoxide is typically carried out in a hydrocarbon solvent under an inert atmosphere. Non-limiting examples of suitable solvents include toluene, heptane, hexane, octane, and the like. The preferred solvent is hexane.

The molar ratio of metal alkoxide to halogenating agent in the halogenation step is generally in the range of about 6: 1 to about 1: 3, and preferably in the range of about 3: 1 to about 1: 2. A more preferred range is from about 2: 1 to about 1: 2, and a most preferred range is about 1: 1.

The halogenation step is generally carried out at a temperature ranging from about 0 ℃ to about 100 ℃ and for a reaction time ranging from about 0.5 hours to about 24 hours. The halogenation step is preferably conducted at a temperature in the range of about 20 to about 90 c and the reaction time is preferably in the range of about 1 to about 4 hours.

Once the halogenation step is carried out and the metal dialkoxide is halogenated, the product "a" is subjected to one or more halogenation/titanation steps.

In one or more halogenation/titanation steps, the halogenation/titanation agent is preferably a tetra-substituted titanium compound, all four substituents being the same and the substituent being a halide, or an alkoxy or phenoxy group containing 2 to 10 carbon atoms, e.g. TiCl₄Or Ti (OR)₄. The halogenation/titanation agent is preferably a chlorination/titanation agent.

The preferred chlorinating/titanating agents may be a single compound or a mixture of compounds. The process of the present invention provides an activated catalyst after the first chlorination/titanation step; however, the chlorination/titanation is preferably carried out at least twice, each time using a different compound or mixture of compounds, including the use of stronger chlorinating/titanating agents with each successive chlorination/titanation step.

The first chlorinating/titanating agent is preferably a weak titanating agent, for example, a blend of a titanium halide and an organotitanate. The first chlorinating/titanating agent is more preferably TiCl₄And Ti (OBu)₄Of a blend of (1), TiCl₄/Ti(OBu)₄From about 0.5: 1 to about 6: 1, and most preferably from about 2: 1 to about 3: 1. It is believed that the blend of titanium halide and organotitanate reacts to form titanium alkoxide halide, Ti (OR)_aX_bWhere OR and X are alkoxy and halide, respectively, a + b is the valence of titanium, typically 4, and both a and b may be fractional, for example a ═ 2.5, b ═ 1.5.

Alternatively, the first chlorinating/titanating agent may be a single compound. An example of the first chlorinating/titanating agent as a single compound is Ti (OC)₂H₅)₃Cl、Ti(OC₂H₅)₃Cl、Ti(OC₃H₇)₂Cl₂、Ti(OC₃H₇)₃Cl、Ti(OC₄H₉)Cl₃、Ti(OC₆H₁₃)₂Cl₂、Ti(OC₂H₅)₂Br₂And Ti (OC)₁₂H₅)C₃。

The first halogenation/titanation step is generally carried out in a hydrocarbon solvent. Non-limiting examples of suitable hydrocarbon solvents include heptane, hexane, toluene, octane, and the like. The preferred solvent is hexane.

After the addition of the first halogenating/titanating agent to the soluble product "A" at room temperature, the solid product "B" precipitates out.

The amount of halogenation/titanation agent used must be sufficient to precipitate the solid product from solution. Generally, the halogenating/titanating agent is used in an amount, based on the titanium to metal ratio, generally in the range of from about 0.5 to about 5, preferably in the range of from about 1 to about 4, and most preferably in the range of from about 1.5 to about 2.5.

The solid product "B" precipitated in the first titanation step is then recovered by any suitable recovery technique and washed with a hydrocarbon solvent.

Compounds suitable for use as the second halogenating/titanating agent include those suitable for use as the first halogenating/titanating agent, except that the second halogenating/titanating agent is preferably a stronger agent. The stronger second halogenating/titanating agent is preferably a titanium halide, more preferably titanium tetrachloride [ TiCl ]₄]。

The second halogenation/titanation step is generally carried out by slurrying the solid product "B" in a hydrocarbon solvent to produce the reaction product, i.e., catalyst component "C". The listed hydrocarbon solvents suitable for the first halogenation/titanation step are all usable. Generally, the amount of titanium tetrachloride used will generally range from about 0.1 to about 5 equivalents, preferably from about 0.15 to about 4 equivalents, and most preferably from about 0.175 to about 2.5 equivalents.

Catalyst component "C" can be combined with an organoaluminum cocatalyst component ("preactivator") to form a preactivated catalyst suitable for olefin polymerization. In general, the cocatalyst used together with the transition metal containing the catalyst component "C" is an organometallic compound of a metal of groups Ia, IIa, IIIa, such as aluminum alkyl, aluminum alkyl hydride (aluminum alkyl hydrides), lithium aluminum alkyl, zinc alkyl, magnesium alkyl, etc.

The preactivating agent is preferably an organoaluminum compound. The organoaluminum preactivating agent is preferably of the formula AlR ^₃Wherein R is an alkyl group having 1 to 8 carbon atoms or a halide, R' may be the same or different, and at least one R is an alkyl group. More preferably, the organoaluminum preactivating agent is a trialkylaluminum, such as Trimethylaluminum (TMA), Triethylaluminum (TEAL) and triisobutylaluminum (TiBAl). The most preferred preactivating agent is TEAl. The ratio of Al to titanium is from 0.01: 1 to 2: 1, preferably from 0.25: 1 to 1.2: 1.

The pre-activated catalyst is then heat treated at a temperature in the range of about 90-150 c, preferably in the range of about 100 c and 125 c. The slurry is allowed to stand at this elevated temperature for a retention time in the range of about 0.5 to 24 hours, with a preferred range of retention time being about 1 to 4 hours. Subsequently, the final solid catalyst is recovered and washed with a hydrocarbon solvent.

Alternatively, the electron donor may be added together with the halogenating agent, the weak first halogenating/titanating agent, and the stronger second halogenating/titanating agent. Most preferably, an electron donor is used in the second halogenation/titanation step.

The electron donors useful for the preparation of polyolefins are well known and any suitable electron donor that provides a suitable catalyst may be used in the present invention.

The electron donor, also known as a Lewis base, is an organic compound of oxygen, nitrogen, phosphorus, or sulfur that provides an electron pair to the catalyst.

The electron donor may be a monofunctional or polyfunctional compound, preferably selected from aliphatic or aromatic carboxylic acids and their alkyl, aliphatic or cyclic ethers, ketones, vinyl esters, acryloyl derivatives, in particular alkyl acrylates or methacrylates and silanes. A preferred example of a suitable electron donor is di-n-butyl phthalate. More preferred examples of suitable electron donors are of the formula RSi (OR')₃Alkylsilylalkoxides of (meth) acrylic acid, e.g. methyl (triethoxy) silane [ MeSi (OEt)₃)]Wherein R and R' are alkyl groups containing 1 to 5 carbon atoms, which may be the same or different.

The support for the catalyst system of the present invention should be an inert solid that is chemically unreactive with any conventional Ziegler-Natta catalyst component. The carrier is preferably a magnesium compound. Examples of magnesium compounds used to provide a support for the catalyst component are magnesium halides, dialkoxymagnesiums, alkoxymagnesium halides and magnesium carboxylates. The preferred magnesium compound is magnesium chloride (MgCl)₂)。

Alternatively, the Ziegler-Natta catalyst may be prepolymerized. The prepolymerization is carried out by contacting the catalyst with a small amount of the monomer after the catalyst has been contacted with the cocatalyst. A description of the prepolymerization process can be found in U.S. Pat. nos. 5,106,804; 5,135,158, respectively; and 5,594,071, incorporated herein by reference.

For example, the catalysts of the present invention are useful for catalyzing the polymerization of ethylene, propylene, butenes, pentenes, hexenes, 4-methylpentenes and other α -olefins having at least 2 carbon atoms, and mixtures thereof.

The catalysts produced by the present invention have extremely high activity depending at least in part on the olefin polymerization conditions. Typically, the catalyst activity is at least 6,000 grams of polyethylene per gram of catalyst (gPE/g), but may be greater than 100,000 grams of polyethylene per gram of catalyst.

In addition, the catalysts prepared according to the invention provide polymers with excellent fluff morphology. Thus, the catalyst of the present invention provides large polymer particles having a uniform particle size distribution, wherein small, extremely fine particles (less than about 125 microns) are present only in low concentrations. The catalyst of the present invention comprises a large, easily convertible powder having a high powder bulk density, which is suitable for use in a polymerization process.

The polymerization process may be a bulk, slurry or gas phase process. The catalysts of the invention are preferably used in slurry polymerization. The polymerization conditions (e.g., temperature and pressure) depend on the type of apparatus used and the type of polymerization process used and are well known in the art. For example, the temperature may range from about 50 ℃ to about 200 ℃ and the pressure may range from about 10 pounds per inch to about 800 pounds per inch²。

The olefin monomer may be fed to the polymerization zone in the presence of a diluent which is a non-reactive heat carrier that is liquid under the reaction conditions, examples of such diluents are hexane and isobutane, for the copolymerization of ethylene and another α -olefin, such as butene or hexene, the second α -olefin content may be in the range of 0.01 to 20 mole percent, preferably 0.02 to 10 mole percent.

For the polymerization process, it is preferable that an internal electron donor and an external electron donor, or a stereoregular Selectivity Control Agent (SCA) included in the catalyst synthesis activate the catalyst at the polymerization reaction. The internal electron donor can be used in the catalyst formation reaction in the chlorination or chlorination/titanation step. Compounds suitable as internal electron donors for the preparation of conventional supported Ziegler-Natta catalyst components include ethers, diethers, ketones, lactones, N, P and/or S atom containing electron donors and specific classes of esters. Particularly suitable are phthalic acid esters, such as diisobutyl phthalate, dioctyl phthalate, diphenyl phthalate and benzylbutyl phthalate; malonic esters such as diisobutyl malonate and diethyl malonate; alkyl and aryl neopentanoates; alkyl, cycloalkyl and aryl maleates; alkyl and aryl carbonates, such as diisobutyl carbonate, ethylphenyl carbonate and diphenyl carbonate; succinic acid esters such as monoethyl succinate and diethyl succinate.

External electron donors useful in preparing the catalysts of the invention include organosilane compounds. For example of the formula SiR_m(OR′)_4-mWherein R is selected from the group consisting of alkyl, cycloalkyl, aryl, and vinyl; r' is alkyl; m is 0-3, R may be the same as R'; when m is 0, 1 or 2, the radicals R' may be identical or different; when m is 2 or 3, the R groups may be the same or different.

The external electron donor of the present invention is preferably selected from silane compounds represented by the following formula:

wherein R1 and R4 are both alkyl or cycloalkyl groups containing a primary, secondary or tertiary carbon atom attached to the silicon, and R1 and R4 may be the same or different; r2 and R3 are alkyl or aryl. R1 may be methyl, isopropyl, cyclopentyl, cyclohexyl, or tert-butyl; r2 and R3 may be methyl, ethyl, propyl, or butyl, and need not be the same; r4 can also be methyl, isopropyl, cyclopentyl, cyclohexyl or tert-butyl. Specific external donors are Cyclohexylmethyldimethoxysilane (CMDS), diisopropyldimethoxysilane (DIDS), Cyclohexylisopropyldimethoxysilane (CIDS), dicyclopentyldimethoxysilane (CPDS) or di-tert-butyldimethoxysilane (DTDS).

The molecular weight distribution (Mw/Mn) of the polyethylene produced with the above catalyst is at least 4.0, preferably at least 5.0, more preferably at least 6.0, and most preferably at least 7.0.

Examples

The present invention is generally as described above and the following examples are merely illustrative of certain embodiments of the present invention. It is to be understood that these examples are given by way of illustration and are not intended to limit the specification or the appended claims in any way.

Preparation of the catalyst

This example illustrates a morphology-controlled polyethylene catalyst that facilitates fine tuning of the intrinsic Molecular Weight Distribution (MWD) of the polymer produced from the catalyst. By adjusting the molecular weight distribution, a single catalyst system can be used to produce various grades of polymer for applications ranging from injection molding (narrow MWD) to blown film (broad MWD).

The catalyst was produced as follows:

step 1

BuEtMg/DIAE/TEAL (1: 0.6: 0.03) + 2-ethylhexanol (2.09) was used to prepare soluble intermediate A.

Step 2

From intermediate A +1.0ClTi (OPr)₃To obtain a soluble intermediate B.

Step 3

From intermediate B + Ti (OBu)₄/TiCl₄(2.0: 1.0) to obtain a solid precatalyst.

Step 4

Precatalyst + TiCl₄(0.25) + TEAl to give the final catalyst.

Step 5

The final catalyst was then heat treated at 90 ℃ for the time indicated in table 1 below.

Polymerisation reaction

The reactor for polymerizing ethylene (designed autoclave) had a capacity of 4 liters and was equipped with four mixing baffles and two mixing propellers of counter-pitch. Ethylene and hydrogen were passed into the reaction vessel through a Teledyne-Hastings phase comparator (Raydit) mass flow controller while maintaining the internal reaction pressure constant with a dome equipped with a back pressure regulator. The reaction temperature was maintained using a Kammer valve regulating (in the reactor jacket) steam and cold water connected to a Barber-Coleman controller.

Hexane was used as a diluent.Test variables: temperature 80 ℃ reaction time 60 minutes pressure 125 lb/in²Catalyst 0.2 ml of slurry (ca. 10 mg catalyst) cocatalyst TEAL @0.25 mmol/l flow rate H₂/C₂@0.25

TABLE 1

Time (hour, 90 ℃ C.)	Co-catalyst	SR5	M_w/M_n
Time (hour, 90 ℃ C.)	Co-catalyst	SR5	M_w/M_n	0 (control)	TEAl	10.4	5.4
2	TEAl	11.1	6.7	0 (control)	TEAl	10.4	5.4
2	TEAl	11.1	6.7	4	TEAl	11.7	6.8
6	TEAl	12.5	6.4	4	TEAl	11.7	6.8
6	TEAl	12.5	6.4	24	TEAl	12.8	6.8

The catalyst solution was sampled at 2, 4, 6 and 24 hours. As shown by SR5 and GPC data shown in table 1 and fig. 1(TEAl promoter), the heat treatment at this stage significantly broadened the intrinsic molecular weight distribution. It can also be seen that the molecular weight distribution steadily increased throughout the first 6 hours of heating. After that, the widening level flattens out. In addition, the data show that it is possible to fine tune the catalyst to achieve the desired molecular weight distribution of the polymer depending on the application of the polymer. Finally, the catalyst was found not to lose high activity or good fluff morphology upon heat treatment.

While illustrative embodiments of the invention have been described in detail, it should be understood that various other modifications of the invention are apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the patentable and novel features of the invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains.

Claims

1. Polyolefin catalyst, characterized in that it is obtained by a process comprising the following steps

a) Contacting with a halogenating agent a compound of the formula Mg (OR')₂The halogenating agent being capable of replacing an alkoxy group with a halogen to form a reaction product A, wherein R' is a hydrocarbyl or substituted hydrocarbyl group containing from 1 to 20 carbon atoms;

b) contacting the reaction product a with a first halogenating/titanating agent to form a reaction product B;

c) contacting reaction product B with a second stronger halogenating/titanating agent to form reaction product C;

d) contacting reaction product C with an organoaluminum preactivating agent to form a preactivated catalyst;

e) the preactivated catalyst is heated at a temperature in the range of 90 to 150 ℃ for a time period in the range of about 30 minutes to 24 hours.

2. The catalyst of claim 1 wherein the soluble dialkoxy magnesium compound is the reaction product of an alkyl magnesium of the formula MgRR 'wherein R, R' of the alkyl magnesium is an alkyl group containing 1 to 10 carbon atoms, which may be the same or different, and an alcohol of the formula R "OH wherein R" is an alkyl group containing 4 to 20 carbon atoms.

3. The catalyst of claim 2 wherein the soluble magnesium compound is magnesium bis (2-ethylhexoxide).

4. The catalyst of claim 2 wherein the alkyl magnesium compound is diethylmagnesium, dipropylmagnesium, dibutylmagnesium or butylethylmagnesium.

5. The catalyst of claim 2 wherein the alcohol is ethanol, propanol, isopropanol, butanol, isobutanol or 2-ethylhexanol.

6. The catalyst of claim 2 wherein the reaction further comprises an aluminum alkyl.

7. The catalyst of claim 6 wherein the aluminum alkyl is triethylaluminum.

8. The catalyst of claim 7 wherein the ratio of aluminum alkyl to magnesium is from 0.001: 1 to 1: 1.

9. The catalyst of claim 1 having a fluff morphology suitable for polymerization processes and providing a uniform particle size distribution and a small amount of particles having a particle size of less than about 125 microns.

10. The catalyst of claim 2, wherein the reaction further comprises an electron donor.

11. The catalyst of claim 10 wherein the ratio of electron donor to magnesium is from about 0: 1 to about 10: 1.

12. The catalyst of claim 11 wherein the electron donor is an ether.

13. The catalyst of claim 1 wherein the halogenating agent has the formula of ClAR'_xWherein A is a non-reducing oxophilic compound, R' ″_xIs a hydrocarbon radical having 2 to 6 carbon atomsAnd the moiety, x, is the valence of A minus 1.

14. The catalyst of claim 1 wherein the weak first chlorinating/titanating agent is a blend of two tetra-substituted titanium compounds, all four substituents being the same and the substituents being halide or alkoxy or phenoxy groups containing from 2 to 10 carbon atoms.

15. The catalyst of claim 14 wherein the weak first chlorinating/titanating agent is a blend of a titanium halide and an organotitanate.

16. The catalyst of claim 15 wherein the weak first chlorinating/titanating agent is TiCl₄And Ti (OBu)₄Of a blend of (1), TiCl₄/Ti(OBu)₄Is 0.5: 1-6: 1.

17. The catalyst of claim 1, wherein step b) further comprises a compound of the formula RSi (OR')₃Wherein R and R' are alkyl groups having 1 to 5 carbon atoms, and may be the same or different.

18. The catalyst of claim 17 wherein the electron donor is methyltriethoxysilane.

19. The catalyst of claim 1 wherein said stronger second chlorinating/titanating agent is a titanium halide.

20. The catalyst of claim 19 wherein said second stronger chlorinating/titanating agent is titanium tetrachloride wherein the ratio of titanium to magnesium is from 0: 1 to 2: 1.

21. The catalyst of claim 1 wherein the organoaluminum preactivating agent is of the formula AlR ^₃Wherein R is an alkane having 1 to 8 carbon atomsOr a halide, R ^ s may be the same or different, and at least one R ^ s is an alkyl group.

22. The catalyst of claim 21 wherein the organoaluminum preactivating agent is a trialkylaluminum.

23. The catalyst of claim 22 wherein the ratio of aluminum to titanium is in the range of 0.1: 1 to 2: 1.

24. A polymer characterized in that it is prepared by a process comprising the steps of:

a) contacting one or more α -olefin monomers with each other in the presence of a catalyst under polymerization conditions;

wherein the catalyst is prepared by the following steps:

i) with halogenating agents and compounds of the formula Mg (OR')₂In contact with a soluble dialkoxy magnesium compound, the halogenating agent being capable ofReplacing an alkoxy group with a halogen to form reaction product A, wherein R' is a hydrocarbyl or substituted hydrocarbyl group containing 1 to 20 carbon atoms;

ii) contacting the reaction product A with a first halogenating/titanating agent to form a reaction product B;

iii) contacting reaction product B with a second stronger halogenating/titanating agent to form reaction product C;

iv) contacting the reaction product C with an organoaluminum preactivating agent to form a preactivated catalyst;

v) heating the preactivated catalyst at a temperature in the range of 90 to 150 ℃ for a time in the range of about 30 minutes to 24 hours.

25. The polymer of claim 24 wherein said monomer is ethylene monomer and said polymer is polyethylene.

26. The polymer of claim 25, wherein the polyethylene has a molecular weight distribution greater than about 4.0.

The polymer of claim 24 wherein said polymerization is carried out in bulk, slurry or gas phase.

28. The polymer of claim 24 wherein the soluble dialkoxy magnesium compound is the reaction product of an alkyl magnesium of the formula MgRR 'wherein R, R' of the alkyl magnesium is an alkyl group containing 1 to 10 carbon atoms, which may be the same or different, and an alcohol of the formula R "OH wherein R" is an alkyl group containing 4 to 20 carbon atoms.

29. The polymer of claim 24 wherein the soluble magnesium compound is bis (2-ethylhexyloxy) magnesium, the alkyl magnesium compound is selected from the group consisting of diethylmagnesium, dipropylmagnesium, dibutylmagnesium, and butylethylmagnesium, and the alcohol is selected from the group consisting of ethanol, propanol, isopropanol, butanol, isobutanol, and 2-ethylhexanol.

30. The polymer of claim 25 wherein the polymerization reaction further comprises an aluminum alkyl, wherein the ratio of aluminum alkyl to magnesium is from 0.001: 1 to 1: 1.

31. The polymer of claim 25, wherein any of steps i) -v) further comprises an electron donor, wherein the ratio of electron donor to magnesium is in the range of 0: 1 to 10: 1.

32. The polymer of claim 31, wherein said electron donor is an ether.

33. The polymer of claim 24, wherein the halogenating agent has the formula ClAR'_xWherein A is a non-reducing oxophilic compound, R' ″_xIs a hydrocarbyl moiety containing 2 to 6 carbon atoms, and x is the valence of A minus 1.

34. The polymer of claim 24, characterized in thatCharacterised in that the weak first chlorinating/titanating agent is TiCl₄And Ti (OBu)₄Of a blend of (1), TiCl₄/Ti(OBu)₄Is 0.5: 1-6: 1.

35. The polymer of claim 24 wherein said second stronger chlorinating/titanating agent is titanium tetrachloride wherein the ratio of titanium to magnesium is from 0: 1 to 2: 1.

36. The polymer of claim 24 wherein said organoaluminum preactivating agent is of the formula AlR ^₃Wherein R is an alkyl group having 1 to 8 carbon atoms or a halide, R 'is the same or different, at least one R' is an alkyl group, and the ratio of Al to titanium is 0.1: 1 to 2: 1.

37. A method for producing a catalyst, characterized by comprising:

38. The method of claim 37, wherein the soluble dialkoxy magnesium compound is the reaction product of an alkyl magnesium of the formula MgRR 'wherein R, R' of the alkyl magnesium is an alkyl group containing 1 to 10 carbon atoms, which may be the same or different, and an alcohol of the formula R "OH wherein R" of the alcohol is an alkyl group containing 4 to 20 carbon atoms.

39. The method of claim 37, wherein the soluble magnesium compound is magnesium bis (2-ethylhexyloxide).

40. The method of claim 38, wherein the alkyl magnesium compound is diethylmagnesium, dipropylmagnesium, dibutylmagnesium, or butylethylmagnesium.

41. The method of claim 38, wherein the alcohol is ethanol, propanol, isopropanol, butanol, isobutanol, or 2-ethylhexanol.

42. The method of claim 38, wherein the reaction further comprises an aluminum alkyl.

43. The method of claim 42 wherein said aluminum alkyl is triethylaluminum.

44. A method according to claim 43, wherein the ratio of aluminum alkyl to magnesium is from 0.001: 1 to 1: 1.

45. The process of claim 37 wherein the catalyst has a fluff morphology suitable for polymerization processes and provides a uniform particle size distribution and a small amount of particles having a particle size of less than about 125 microns.

46. The method of claim 38, wherein the reaction further comprises an electron donor.

47. The method of claim 46, wherein the ratio of electron donor to magnesium is in the range of 0: 1 to 10: 1.

48. The method of claim 37, wherein the method is performed in a batch modeCharacterized in that the halogenating agent has the general formula of ClAR_xWherein A is a non-reducing oxophilic compound, R' ″_xIs a hydrocarbyl moiety containing 2 to 6 carbon atoms, and x is the valence of A minus 1.

49. The process of claim 48 wherein said chlorinating agent is ClTi (O)ⁱPr)₃。

50. The method of claim 49 wherein the ratio of titanium to magnesium is between 0.5 and 5.0.

51. The method of claim 37 wherein the weak first chlorinating/titanating agent is a blend of two tetra-substituted titanium compounds, all four substituents being the same and the substituents being halide or alkoxy groups having from 2 to 10 carbon atoms or phenoxy groups.

52. A method according to claim 51 wherein the weak first chlorinating/titanating agent is a blend of a titanium halide and an organotitanate.

53. The method of claim 51 wherein said weak first chlorinating/titanating agent is TiCl₄And Ti (OBu)₄Of a blend of (1), TiCl₄/Ti(OBu)₄Is 0.5: 1-6: 1.

54. The method of claim 37, wherein the reaction further comprises an electron donor.

55. The process of claim 37 wherein said stronger second chlorinating/titanating agent is a titanium halide.

56. The method of claim 55 wherein said second stronger chlorinating/titanating agent is titanium tetrachloride wherein the ratio of titanium to magnesium is from 0: 1 to 2: 1.

57. The method of claim 56, wherein the titanium tetrachloride is used in an amount of 0.1 to 5.0 equivalents.

58. The process of claim 37 wherein the organoaluminum preactivating agent is of the formula AlR ^₃Wherein R is an alkyl group having 1 to 8 carbon atoms or a halide, R' may be the same or different, and at least one R is an alkyl group.

59. A process according to claim 58 wherein the organoaluminum preactivating agent is a trialkylaluminum.

60. The method of claim 59 wherein the ratio of aluminum to titanium is in the range of 0.1: 1 to 2: 1.

61. The process of claim 60 wherein the organoaluminum preactivating agent is TEAL.

62. The method of claim 37, wherein the electron donor is present in any of steps a), b), c), or d) in a ratio of 0: 1 to 10: 1.

63. The method of claim 37, wherein the catalyst is used to produce polyethylene having a desired molecular weight distribution.

Process for the polymerization of 64, α -olefins, characterized in that it comprises:

wherein the catalyst is prepared by the following steps:

i) with halogenating agents and compounds of the formula Mg (OR')₂Is capable of replacing an alkoxy group with a halogen to form a halogenA reaction product a wherein R "is a hydrocarbyl or substituted hydrocarbyl group containing 1 to 20 carbon atoms;

65. The method of claim 64, further comprising:

b) the polyolefin polymer is discharged.

66. The method of claim 64 wherein said monomer is ethylene monomer and said polymer is polyethylene.

67. The method of claim 66, wherein the polyethylene has a molecular weight distribution of at least 4.0.

The process of claim 64 wherein the polymerization is carried out in bulk, slurry or gas phase.

69. The method of claim 64 wherein the halogenating agent has the formula ClAR'_XWherein A is a non-reducing oxophilic compound, R' ″_xIs a hydrocarbyl moiety containing 2 to 6 carbon atoms.

70. The method of claim 69 wherein the halogenating agent is ClTi (oi Pr)₃。

71. The method of claim 64 wherein said first halogenating/titanating agent is a titanium halide of the formula TiCl₄/Ti(OR″″)₄Wherein R' is a quaternary ammonium compound, or a mixture of two tetra-substituted titanium compounds of (1)₄Is a hydrocarbyl moiety containing 2 to 6 carbon atoms.

72. The method of claim 71 wherein said first halogenating/titanating agent is TiCl₄And Ti (OBu)₄Of a blend of (1), TiCl₄/Ti(OBu)₄The ratio of the ratio is 0.5: 1-6: 1.

73. The method of claim 72 wherein the ratio of titanium to magnesium present in step ii) is from 0.5 to 5.0.

74. The process of claim 64 wherein said stronger second halogenating/titanating agent is TiCl₄。

75. The process of claim 74, characterized in that said TiCl is₄The amount of (B) is 0.1-5.0 equivalent.

76. The process of claim 64 wherein the organoaluminum preactivating agent is TEAL.

77. The method of claim 64, wherein an electron donor is present in any of steps i-iv and the ratio of electron donor to metal is from 0: 1 to 10: 1.