JPH04275311A - Production of polyolefin - Google Patents

Abstract

PURPOSE:To provide a method for producing a polyolefin having improved powder morphology and permitting to readily adjust the mol.wt. of the polyolefin. CONSTITUTION:One or more olefins are polymerized or copolymerized in the presence of a catalyst comprising the following components (A),(B) and (C). (A) A magnesium compound of the formula: Mg(OR)2...(1) (R is alkyl, cycloalkyl, aryl, or aralkyl; the R groups may be mutually same or different. (B) A transition metal compound containing a group having conjugated pi-electrons as a ligand. (C) An aluminoxane.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing olefin polymers and copolymers, and more particularly to a method for producing polyolefins that can improve powder morphology and facilitate adjustment of molecular weight distribution.

0002

BACKGROUND OF THE INVENTION Conventionally, methods for producing polyolefins using solid titanium-based catalysts and organoaluminum compounds have been known. Generally, the olefin (co)polymer obtained by this method is
It is characterized by a wide molecular weight distribution and wide composition distribution. Therefore, there were problems such as poor transparency when formed into a film.

On the other hand, in recent years, homogeneous catalysts with high activity and narrow molecular weight distribution and composition distribution have been proposed (Japanese Unexamined Patent Publication No. 58-198).
No. 303). However, the olefin (co)polymer obtained using this homogeneous catalyst is difficult to separate from the solvent because the resulting polymer dissolves in the solvent or becomes gel-like. (2) It has various drawbacks such as the fact that the produced polymer adheres to the reaction vessel, and does not fully meet the requirements.

[0004] In contrast, a technique has been proposed that uses a solid material obtained by supporting the above-mentioned homogeneous catalyst on an inorganic oxide carrier (Japanese Patent Laid-Open No. 108610/1983). However, the activity per carrier is low, and there are problems such as frequent formation of films and gels due to the carrier remaining in the polymer.
It does not fully meet the requirements. Furthermore, as a means for adjusting the molecular weight distribution in the above-mentioned homogeneous catalyst, there is also a method (1) of using two or more metallocene compounds (Japanese Unexamined Patent Application Publication No. 1983-1989-1).
35006, JP-A No. 60-35008), ■ A method for polymerizing hafnocene compounds at a specific temperature (JP-A No. 2-75
No. 605) has been proposed, but it still does not fully satisfy the requirements, such as the operation being complicated and the method being usable only under specific conditions. The present invention was made in order to solve the problems of the prior art described above, and aims to provide a method for producing polyolefin that can improve powder morphology (powder properties) and facilitate adjustment of molecular weight distribution. purpose.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a magnesium compound Mg represented by the following formula (A), component (A), component (B) and component (C).
(OR)2...(
b) (R in the formula represents an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and may be the same or different) (B) a group having conjugated π electrons; Provided is a method for producing a polyolefin, characterized in that olefin polymerization or copolymerization is carried out using a catalyst consisting of a transition metal compound (C) aluminoxanes as a ligand.

The present invention will be explained in more detail below. In the catalyst used in the present invention, the magnesium compound represented by the general formula (A) is used as component (A). In this case, compounds in which R in the formula is a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group can be particularly preferably used. Specifically, dimethoxymagnesium, diethoxymagnesium, di-n-
Dialkoxymagnesium such as propoxymagnesium, diisopropoxymagnesium, dibutoxymagnesium, diaryloxymagnesium such as diphenoxymagnesium, diaurkyloxymagnesium such as dibenzyloxymagnesium, ethoxyphenoxymagnesium, butoxyphenoxymagnesium, etc. Examples include alkoxyaryloxymagnesium. These magnesium compounds may be used alone or in combination of two or more.

Furthermore, instead of the magnesium compound of formula (a), a reaction product of metallic magnesium, alcohol, and halogen can also be used. There is no particular restriction on the shape of the metallic magnesium used at this time, and any shape of metallic magnesium may be used, such as granular, ribbon-shaped,
Any powder form or the like can be used. Also,
There are no particular restrictions on the surface condition of magnesium metal, but it is advantageous to use one on which a coating of magnesium oxide or the like is not formed. There are no particular restrictions on the type of alcohol, but lower alcohols having 1 to 6 carbon atoms are preferred, and ethanol is particularly preferred since it provides a solid catalyst component that improves catalyst performance. There are no particular restrictions on the purity or water content of alcohol, but if alcohol with a high water content is used, magnesium hydroxide will be formed on the surface of magnesium metal.
It is preferable to use alcohol of 000 ppm or less,
The lower the water content, the more advantageous it is. Furthermore, as the halogen, bromine or iodine is preferable. The form of the halogen is not particularly limited, and for example, it may be dissolved in an alcoholic solvent and used as a solution.

The amount of alcohol used is usually 2 to 100 mol, preferably 5 to 50 mol per mol of magnesium metal.
Selected within the molar range. If the amount of alcohol is too large, it tends to be difficult to obtain a magnesium compound with good morphology, and if it is too small, the reaction with magnesium metal may not proceed smoothly. In addition, halogen is usually 0.0 per mole of magnesium metal.
001 g atom or more, preferably 0.0005 g atom or more, more preferably 0.001 g atom or more. When the amount of halogen used is less than 0.0001 g atom, when the obtained magnesium compound is used without being pulverized, the amount of titanium supported, the catalyst activity, and the stereoregularity and morphology of the produced polymer are reduced. Therefore, pulverization of the obtained magnesium compound becomes essential, which is not preferable. Further, there is no particular restriction on the upper limit of the amount of halogen used, and it may be selected as appropriate within a range that allows the desired magnesium compound to be obtained. Furthermore, by appropriately selecting the amount of halogen used, the particle size of the resulting magnesium compound can be controlled as desired.

The reaction between magnesium metal, alcohol and halogen can be carried out using a known method. For example, metal magnesium, alcohol, and halogen are usually heated under reflux for 2 hours until no hydrogen gas is generated.
A desired magnesium compound can be obtained by reacting for about 30 hours. Specifically, when using iodine as a halogen, solid iodine is added to a mixture of metallic magnesium and alcohol, and then heated and refluxed, and alcohol containing iodine is used in a mixture of metallic magnesium and alcohol. A method in which a solution is added dropwise and then heated to reflux, a method in which an alcoholic solution containing iodine is added dropwise while heating a mixture of metallic magnesium and alcohol, etc. can be used. In either method, it is preferable to conduct the reaction under an inert gas atmosphere such as nitrogen gas or argon gas, using an inert organic solvent such as a saturated hydrocarbon such as n-hexane as the case may be. Regarding the introduction of metallic magnesium and alcohol, it is not necessary to add the entire amount of each to the reaction tank from the beginning, and they may be added in portions. For example, a method is to add the entire amount of alcohol from the beginning and then add metallic magnesium in several portions. This method can prevent the temporary generation of large amounts of hydrogen gas, which is extremely desirable from a safety standpoint, and allows for the reduction of the size of the reaction tank. This prevents the entrainment of alcohol and halogen droplets. The number of times of division may be determined in consideration of the scale of the reaction tank and is not particularly limited, but considering the complexity of the operation, it is usually selected in the range of 5 to 10 times.

[0010] The reaction itself may be either a batch type or a continuous type, and as a modified method, a small amount of metallic magnesium is first added to the alcohol that has been added in its entirety from the beginning, and the products produced by the reaction are separated into a separate tank. It is also possible to repeat the operation of removing it and then adding a small amount of metallic magnesium again. The magnesium compound obtained in this manner can be used in the next step without pulverization or classification operations to make the particle size uniform.

The transition metal compound having a group having conjugated π electrons as a ligand used as component (B) in the present invention is not particularly limited, but for example, the following general formula (B) is used.
R4p(R1)2MR2R3
...Compounds shown in (b) are mentioned. Here, M is a transition metal such as titanium, zirconium, or hafnium, R1 is a cycloalkadienyl group, R2 and R3 are each a hydrocarbyl group or alkoxy group having 1 to 20 carbon atoms, or a halogen atom or a hydrogen atom, and R4 is 2 R1 is an alkylene group having 1 to 4 carbon atoms, and p is 0 or 1. Examples of the cycloalkadienyl group R1 include a cyclopentadienyl group, a methylcyclopentadienyl group, a pentamethylcyclopentadienyl group, an indenyl group, and a tetrahydroindenyl group. Specific examples of hydrocarbyl groups for R2 and R3 include methyl group, ethyl group, propyl group, butyl group, amyl group, isoamyl group, hexyl group, isobutyl group, heptyl group, octyl group, nonyl group, decyl group, Examples include cetyl group, 2-ethylhexyl group, and phenyl group. Examples of the alkoxy group include a methoxy group, ethoxy group, propoxy group, and butoxy group, and examples of the halogen atom include chlorine, bromine, and fluorine.

Specific examples of the compound represented by the general formula (b) include bis(cyclopentadienyl)dimethyltitanium, bis(cyclopentadienyl)methylhydrotitanium, and bis(methylcyclopentadienyl)dimethyltitanium. , bis(pentamethylcyclopentadienyl)dimethyltitanium, bis(cyclopentadienyl)methylchlorotitanium, bis(cyclopentadienyl)dichlorotitanium, bis(cyclopentadienyl)chlorohydrotitanium, bis(indenyl)dimethyl Titanium, bis(indenyl)dichlorotitanium, ethylenebis(indenyl)dichlorozirconium, ethylenebis(tetrahydroindenyl)dichlorozirconium, bis(cyclopentadienyl)dimethylzirconium, bis(cyclopentadienyl)methylhydrozirconium, bis( methylcyclopentadienyl)
Dimethylzirconium, bis(pentamethylcyclopentadienyl)dimethylzirconium, bis(cyclopentadienyl)methylchlorozirconium, bis(cyclopentadienyl)dichlorozirconium, bis(cyclopentadienyl)chlorohydrozirconium, bis(indenyl) ) Dimethylzirconium, ethylenebis(indenyl)dichlorozirconium, ethylenebis(tetrahydroindenyl)dichlorozirconium, bis(indenyl)dichlorozirconium, bis(cyclopentadienyl)dimethylhafnium, bis(cyclopentadienyl)methylhydrohafnium, Bis(cyclopentadienyl)dichlorohafnium, bis(cyclopentadienyl)chlorohydrohafnium, and the like.

[0013] In the present invention, examples of the aluminoxanes used as component (C) include reaction products of water and organoaluminum compounds. Furthermore, a reaction product of a hydrous compound such as copper sulfate pentahydrate and an organoaluminium compound, or a mixture of these reaction products and organoaluminum can also be used. The organoaluminum compound used to produce the aluminoxane is not particularly limited, but for example, general formula (c) R53Al
... (c) (R5 is an alkyl group having 1 to 8 carbon atoms), and trimethylaluminum and triisobutylaluminum are particularly preferred. These compounds may be used alone or in combination of two or more.

Each component (A) to (C) of the catalyst in the present invention
) may be added to the system after being brought into contact with each other in advance, or may be brought into contact within the system. Moreover, the order in which the components (A) to (C) are brought into contact is not limited, and they can be brought into contact in any order. Preferred contact modes for each component (A) to (C) include:
■ Method of reacting components (A) and (B) in advance and adding component (C) during polymerization ■ Component (A) and (B)
Method of reacting component ) and part of component (C) in advance and adding the remaining component (C) during polymerization■(A)~
A method of reacting component (C) in advance and then adding the component (A) and (C) in advance, and then adding (B) during polymerization
Examples include a method of adding ingredients.

The ratio of each component (A) to (C) in the catalyst of the present invention is 1 mol of component (A) to 1 mol of component (B).
0-4 to 10-1 mol, especially 10-3 to 0.05 mol
It is preferable to set it to 1. In addition, for 1 mol of component (B), 101 to 106 mol of component (C), especially 102
It is preferable to set it as 105 mol. In the method of the present invention, polymerization is carried out using a catalyst consisting of the components (A) to (C) described above. Here, "polymerization" includes homopolymerization as well as
It also includes copolymerization, prepolymerization, etc. Further, the polymerization method is not particularly limited, and any method such as solution polymerization, suspension polymerization, and gas phase polymerization can be employed.

In the present invention, the molecular weight distribution can be easily adjusted by adding hydrogen to the system during polymerization. Since the polymerization system in the method of the present invention is sensitive to hydrogen, the amount of water added may be very small. Specifically, the hydrogen partial pressure is set to a maximum of 2 Kg/cm2.G, preferably 0.1 Kg/cm2.G or less. Hydrogen partial pressure is 2
If it exceeds Kg/cm2·G, the molecular weight and polymerization activity will decrease, which is not preferable.

In the present invention, any olefin such as α-olefin and cyclic olefin can be used as a monomer. In this case, examples of the α-olefin include ethylene, propylene, 1-butene, 1-hexene, 1-octene, and 1-decene. In addition, examples of the cyclic olefin include cyclobutene, cyclopentene, cyclohexene, cycloheptene,
Examples include cyclooctene. Furthermore, in the present invention, copolymerization can also be carried out using unsaturated monomer components other than olefins that are copolymerizable with olefins.

Regarding the polymerization conditions, the ratio of the catalyst to the reaction raw materials can be set arbitrarily. In addition, the polymerization temperature is usually -50 to 200°C, preferably 0 to 120°C.
It can be ℃. When using a polymerization solvent, for example, aliphatic hydrocarbons such as isobutene, pentane, n-hexane, and n-heptane, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, and fats such as cyclopentane, cyclohexane, and methylcyclohexane are used. Cyclic hydrocarbons, halogenated hydrocarbons such as chloroform, dichloromethane, etc. can be used. These solvents may be used alone or in combination of two or more.

[0019]

[Examples] Next, the present invention will be specifically illustrated by examples, but the present invention is not limited to the following examples. Example 1 <Preparation of solid product> A glass reactor (inner volume: about 6 liters) equipped with a stirrer was sufficiently purged with nitrogen gas, and about 2,430 g of ethanol, 16 g of iodine, and 160 g of metallic magnesium were added, and the mixture was heated while stirring. The reaction was carried out under heating under reflux conditions until no hydrogen gas was generated from the system, to obtain a solid reaction product. A solid product was obtained by drying the reaction solution containing this solid product under reduced pressure. <Preparation of solid catalyst component> 0.17 m of bis(cyclopentadienyl) dichlorozirconium dissolved in 50 ml of toluene was added to 10 g of the above solid product (average particle size 62 μm).
mol and 35 mmol of methylaluminoxane dissolved in 17 ml of toluene were sequentially added. The reaction was allowed to proceed for 1 hour while stirring slowly at room temperature. Thereafter, the solvent, toluene, was removed by reducing the pressure while stirring slowly at room temperature. Next, heptane was added to make a 400 ml slurry. All of the above operations were performed under a dry nitrogen atmosphere. <Polymerization> Add 400 ml of heptane as a solvent to a 1 liter autoclave equipped with a stirrer, and add 1 mol/ml of heptane as a solvent.
5 ml of a toluene solution of 1 methylaluminoxane and 0.0 ml of the solid catalyst component prepared above in terms of zirconium.
003 mmol was added. The temperature was then raised to 80° C., hydrogen was added to the autoclave at a partial pressure of 0.06 kg/cm 2 ·G, and the autoclave was further pressurized with ethylene so that the internal pressure became 8 kg/cm 2 ·G. Internal pressure is 8Kg/cm2・
Polymerization was carried out for 1 hour while adding ethylene to maintain G. After the polymerization was completed, the autoclave was opened and the polymer slurry was poured into 2 liters of a methanol-hydrochloric acid mixture. The polymer was filtered off, washed with methanol, and then dried at 80°C under reduced pressure for 4 hours. As a result, 2
3.0 g of powder with good fluidity was obtained. Polymerization activity is 84 kg/g-zr, apparent bulk density is 0.17 g/m
l, Mw was 46,000, and Mw/Mn was 4.9.

Comparative Example 1 Bis(
Add 0,003 mmol of cyclopentadienyl dichlorozirconium in terms of zirconium and 2.5 ml of a toluene solution of 1 mol/l methylaluminoxane,
Ethylene polymerization was carried out in the same manner as in Example 1, except that the hydrogen partial pressure was 0.10 Kg/cm2·G. As a result, 23.7 g of polymer was obtained, but the polymer was in the form of a lump. Mw is 38000, Mw/M
n was 2.6. Example 2 The amount of the solid catalyst component prepared in Example 1 was 0,0015 mmol in terms of zirconium, and the amount of the 1 mol/l toluene solution of methylaluminoxane was 2.5 m
Example 1 except that 1 and no hydrogen was added.
Polymerization of ethylene was carried out in the same manner. As a result, 2
2.4 g of polymer was obtained. Polymerization activity is 164kg
/g-zr, apparent bulk density was 0.07 g/ml, Mw was 220,000, and Mw/Mn was 2.6.

Comparative Example 2 <Preparation of solid catalyst component> A solid catalyst component was prepared in the same manner as in Example 1 except that the solid product in Example 1 was not added. <Polymerization> Example 2 except that the solid catalyst component containing no solid product in Example 1 prepared above was used.
Polymerization of ethylene was carried out in the same manner. However, 25 minutes after the start of polymerization, temperature control became impossible.
Polymerization was stopped. When the autoclave was opened, there was significant polymer adhesion to the inner walls.

Example 3 Ethylene polymerization was carried out in the same manner as in Example 2, except that the amount of the 1 mol/l toluene solution of methylaluminoxane used was 10 ml. As a result, 32.0g
of polymer was obtained. Polymerization activity is 234kg/g-z
r, Mw were 220,000, and Mw/Mn was 2.6. Example 4 <Preparation of solid catalyst component> A solid catalyst component was prepared in the same manner as in Example 1 except that methylaluminoxane was not added. <Polymerization> Ethylene polymerization was carried out in the same manner as in Example 3, except that the solid catalyst component containing no methylaluminoxane prepared above was used. As a result, 25.3 g of polymer was obtained. Polymerization activity is 185kg/g-zr
The intrinsic viscosity [η] was 3.1 dl/g.

Example 5 <Preparation of solid catalyst component> A solid catalyst component was prepared in the same manner as in Example 1 except that the amount of solid product used in Example 1 was 1 g. <Polymerization> Using the solid catalyst component prepared above,
Ethylene polymerization was carried out in the same manner as in Example 3, except that the polymerization time was 30 minutes. As a result, 47.7g
of polymer was obtained. Polymerization activity is 349kg/g-z
r, and the intrinsic viscosity [η] was 4.1 dl/g.

Example 6 Preliminary polymerization was carried out to polymerize ethylene. Add 400 ml of heptane as a solvent to a 1 liter autoclave equipped with a stirrer, add 2.5 ml of a 1 mol/l toluene solution of methylaluminoxane, and add 0.001 ml of the solid catalyst component prepared in Example 1 in terms of zirconium.
5 mmol was added. Add 0.17Nl of ethylene, 17
Prepolymerization was carried out at ℃ for 30 minutes. The temperature was then raised to 80° C., and the autoclave was pressurized with ethylene so that the internal pressure became 8 kg/cm 2 ·G. Polymerization was carried out for 1 hour while adding ethylene to maintain the internal pressure at 8 kg/cm2.G. After the polymerization was completed, the autoclave was opened and the polymer slurry was poured into 2 liters of a methanol-hydrochloric acid mixture. After filtering off the polymer and washing with methanol,
Drying was carried out for 4 hours under reduced pressure at °C. As a result, 9.5g
A powder with good fluidity was obtained. Polymerization activity is 69k
g/g-zr.

Example 7 Copolymerization of ethylene and 1-octene was carried out. Add 370 ml of heptane as a solvent to a 1-liter autoclave equipped with a stirrer, and add 30 ml of 1-octene and 1
2 mol/l of a toluene solution of methylaluminoxane
．． 5 ml and 0,0015 mmol of the solid catalyst component prepared in Example 1 in terms of zirconium were added. 60 immediately
The temperature was raised to ℃, and the autoclave internal pressure was 8Kg/cm2・G.
It was pressurized with ethylene so that Internal pressure is 8Kg/cm
Polymerization was carried out for 1 hour while adding ethylene to maintain 2.G. After the polymerization was completed, the autoclave was opened and the polymer slurry was poured into 2 liters of a methanol-hydrochloric acid mixture. The polymer was filtered off, washed with methanol, and then dried at 80°C under reduced pressure for 4 hours. As a result, 25.4 g of powder was obtained. Polymerization activity is 186kg/g-zr
, density is 0.925g/ml, 1-octene content is 4w
t%, Mw were 140000, and Mw/Mn was 2.7.

[0026]

[Effects of the Invention] As explained above, according to the present invention,
The powder morphology of the obtained polyolefin is improved, adhesion of the polymer to the reactor wall and generation of powder lumps can be effectively prevented, and the molecular weight distribution can be easily adjusted.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

Claims (3)

[Claims] [Claim 1] The following (A) component, (B) component and (C
) Component (A) Magnesium compound Mg represented by the following formula (a)
(OR)2
...(a) (R in the formula is an alkyl group, a cycloalkyl group,
represents an aryl group or an aralkyl group, which may be the same or different) (B)
A method for producing a polyolefin, which comprises polymerizing or copolymerizing an olefin using a catalyst consisting of a transition metal compound (C) aluminoxanes having a group having conjugated π electrons as a ligand. 2. The method according to claim 1, wherein (A)
A method for producing a polyolefin, characterized in that a reaction product of metallic magnesium, alcohol, and halogen is used as a component in place of the magnesium compound represented by formula (a). 3. A method for producing a polyolefin according to claim 1 or 2, characterized in that hydrogen is added to the system during the polymerization reaction.