JPH01103607A - Polymerization of olefin - Google Patents

Abstract

PURPOSE:To produce a polyolefin high in bulk density and excellent in flowability and workability, by polymerizing an olefin using a catalyst system comprising a specific transition metal compound and an organoaluminum compound. CONSTITUTION:A catalyst (B) for polymerizing olefins is produced by blending a first catalyst component which is a transition metal compound (a) comprising a solid complex of the given formula (wherein X is halogen; Y is ether; p+q+r=1; 0.17<=p/q+r<=20; 5.5<=r/q<=57; 2<a<=3; and 1<=n<=3) which is composed of Mg atoms., Ti atoms., V atoms., halogen atoms. and ether molecules, and a second catalyst component which is an organoaluminum compound (b) such as triethylaluminum or triisobutylaluminum, with the amount of the component (b) being 1-10mol.% per mol. of the transition metal in the component (a). An olefin (A) is polymerized using the component (B) as the catalyst in the presence or absence of an inert solvent such as hexane under ordinary pressures-100atm at 30-150 deg.C.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for polymerizing olefins.Specifically, an olefin that can advantageously produce polyolefins that have a high bulk density and good fluidity during molding. The present invention relates to a polymerization method.

[Conventional technology]

In recent years, with the development of applications for polyolefins and the progress of processing technology, polyolefins with high molecular weight (low melt index) and good fluidity during molding have become suitable for molding, for example, blow molded products. requested. However, using a conventionally known Ziegler catalyst, for example, a polymerization catalyst system consisting of an organoaluminum compound and a transition metal compound such as titanium or vanadium, the resulting polyolefin generally has poor fluidity during molding under high load. This is not sufficient and has the disadvantage of causing melt fracture on the skin of the molded product.

[Purpose of the invention]

As a result of intensive research to obtain a polyolefin that does not have such drawbacks, the present inventors have found that by using a specific solid complex as a transition metal compound, it has a high bulk density and good fluidity even in a high molecular weight region. The present inventors have discovered that it is possible to produce polyolefins that exhibit excellent properties and processability, and have completed the present invention.

That is, the gist of the present invention is to provide a method for polymerizing olefins using a catalyst system consisting of a transition metal compound and an organoaluminum compound, in which the transition metal compound has the general formula:
(Mgp-Tiq-Vr)Xa-nY (wherein, or a halogen atom, Y represents ether, p+q+r=1,
O0/7≦, F/'6+r≦ko011! r≦r/q≦5
7. λ×a≦3, /≦n≦3. ), which is characterized by using a solid complex composed of Mg atoms, Ti atoms, ■ atoms, halogen atoms, and ether molecules.

[Structure of the invention]

To explain the present invention in detail, the general formula (Mgp・Tiq-Vr) used as the first catalyst component in the present invention will be described.
Mg atom, T1 atom, represented by Xa-nY,
■Solid complexes composed of atoms, halogen atoms, and ether molecules can be easily prepared by co-precipitation from ether solutions containing halogenated magnesium ether complexes, halogenated titanium ether complexes, and halogenated vanadium ether complexes. . It can also be prepared by mixing shredded magnesium halide, titanium halide, and vanadium halide and then performing ether complexation to co-precipitate, or by simultaneously performing mixing and ether complexation to co-precipitate. .

Each of the ether complexes used in the method of the present invention, i.e., the halogenated magnesium ether complex, the halogenated titanium ether complex, and the halogenated vanadium ni, thyl complex, was prepared by the method described in the literature (J, Eng. Norg, Nuc.
l Chem,, 217 (/76.2)/101
and Natiirwissnschaften,
114 (/f!?)/ri/). That is, for example, titanium trihalide is mixed with excess ether and dissolved or extracted under reflux to prepare an ether solution of an ether complex of titanium trihalide,
By lowering the temperature, a 3-ether complex of titanium trihalide is formed, or by adding a hydrocarbon solvent such as n-hexane to this, a 4-ether complex of titanium trihalide is formed. It can be prepared. Also, 37
The 3-ether complex of titanium 10genide is 7'j~ljθ
A l-ether complex of titanium trichloride can be obtained by heat treatment in a temperature range of .degree. Of course,
By changing the heat treatment conditions, it is also possible to prepare a solid complex in which a portion of the 3-ether complex or 4-ether complex remains.

Methods for co-precipitating the desired solid complex from the ether solution containing each ether complex prepared by the above method include cooling the ether solution, removing the ether by evaporation, or using a poor solvent such as a hydrocarbon solvent. A method such as adding a solvent can be adopted. In this case as well, the coordination number of the complex can be changed by changing the conditions, as described when preparing each ether complex.

Used in preparing solid complexes. Any ether may be used as long as it acts as a complexing agent for a halide of magnesium, titanium, or vanadium and as a solvent for the generated ether complex, and examples thereof include aliphatic ethers, alicyclic ethers, and aromatic ethers. In particular, aliphatic ethers such as diethyl ether, diisopropyl ether, dibutyl ether, cyamyl ether, and ether-n-dibutyl ether, and alicyclic ethers such as tetrahydrofuran and dioxane are advantageously used.

The general formula thus obtained, [Mgp-Tlq-vr]X
When a solid complex composed of Mg atoms, T1 atoms, vi atoms, halogen atoms, and ether molecules represented by a-nY is used as a catalyst for olefin polymerization, it has high polymerization activity and high bulk density. Polyolefins having good properties and a wide molecular weight distribution can be advantageously produced. However, as the molar ratio of MXi+V increases, the polymerization activity decreases, so as is clear from the examples, the magnesium content is 0.17≦M%.
/T i + V≦−〇. Furthermore, as is clear from Comparative Examples and 6 below, if the molar ratio of 1V/Ti is small or large, it is not possible to obtain a polyolefin with a wide molecular weight distribution, which is the objective of the present invention. As is clear from the examples, the content is selected from the range lj≦V/Ti≦57.

On the other hand, in the present invention, the organoaluminum compound used as the catalyst co-component includes dialkylaluminum monohalides such as diethylaluminum monochloride, alkylaluminum sesquihalides such as ethylaluminum sesquichloride, diethylaluminum monoethoxide, etc. Examples include monoalkoxydialkyl aluminum, triethyl aluminum, triisobutyl aluminum, trioctyl aluminum, and the like. In particular, triethyl aluminum,
Triimbutylaluminum is preferably used.

The ratio of the first catalyst component to the second catalyst component is 7 to 7 moles of the first component per mole of transition metal in the first component.
It is desirable to select from the range of 0 mol.

The olefin used in the polymerization reaction in the method of the present invention has the general formula R-OH=CH, (wherein R represents a hydrogen atom or a hydrocarbon residue having carbon number/-10, and R has a substituent. α-olefins represented by:

Particularly preferred are linear or branched α-olefins having 1 to 10 carbon atoms. Specifically, for example, ethylene,
Propylene, butene-1, pentene-7, hexene-1
, 4(-methylpentene-11 octene-/, etc.).

The polymerization reaction is carried out by bringing the catalyst and the olefin or olefin mixture into contact at a predetermined temperature and pressure in the presence or absence of an inert solvent.

Inert solvents include pentane, hexane, heptane,
Aliphatic hydrocarbons such as octane and isooctane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, aromatic hydrocarbons such as benzene and toluene, and other arbitrary solvents commonly used in polymerization reactions are used.

Although the polymerization temperature and pressure can be selected from a wide range, the polymerization is usually carried out at a temperature of 30 to 3θ°C and a pressure of normal pressure to 100 atm. In this case, by allowing hydrogen to be present in the polymerization reaction zone, the molecular weight of the resulting polymer can be adjusted arbitrarily even when the polymerization temperature is low.

As detailed above, by polymerizing olefins using the solid complex represented by the general formula (Mgp-Tiq-Vr)Xa-nY as a transition metal compound according to the method of the present invention, it is possible to polymerize olefins having high bulk density. Moreover, a polyolefin having good processability in a high molecular weight region can be obtained with high efficiency.

In addition, the obtained polyolefin has a wide molecular weight distribution, so it is suitable for blow molding, and the molded product has a smooth skin and an extremely good appearance.

Furthermore, it will be explained that by adjusting the die swell during molding within a wide range of molecular weight distribution, the thickness of the molded product can be increased, but the present invention is limited to the following examples without exceeding the gist of the invention. It's not a thing.

In the examples, as a measure representing the breadth of molecular weight distribution,
[Outflow ratio (hereinafter abbreviated as l''-FRJ)' was used. P
R is a value indicating the dependence of melt viscosity on shear stress;
According to TM-D-1, 2.7g-j-7T, respectively, shear stress / 0" dyne/j, / 0" d
It was expressed as the ratio of melt index measured in yne/cd. The larger the PR value, the broader the molecular weight distribution. Furthermore, die swell is a relative indication of the degree of expansion of the extrudate when polyolefin is extruded from a certain nozzle at 190° C. at a certain judgment speed.

Production examples (a) to (c) (a) Preparation of magnesium chloride ether complex Using a Soxhlet extractor, commercially available bulk anhydrous MgCJL, /DI was dehydrated and deoxidized to obtain tetrahydro7 run (hereinafter referred to as 1) under an argon gas atmosphere. '-THFJ)2! A reflux extraction operation was performed using Omt. After about 20 hours, MgOt2
Solids are almost no longer visible. This extracted solution was concentrated to about ioomti, allowed to cool to room temperature, and then dried under a stream of dry nitrogen gas to obtain a white powdery solid. The chemical analysis values (weight %) of the obtained solid were as follows.

(b) Preparation of titanium trichloride ether complex Using a Soxhlet extractor, titanium trichloride (titanium tetrachloride reduced with hydrogen) 61 was extracted under reflux with dehydrated and deoxygenated THFJOO-. After about 70 hours, the titanium trichloride was almost completely dissolved and the THE' phase became a thick purple-brown solution. This was divided into two parts, and one part was left to cool overnight to obtain a blue crystalline solid. The obtained solid was purified n
-Washing with hexane and drying at room temperature under a stream of dry nitrogen to obtain a sky blue solid powder. The chemical analysis values (weight i%) of the obtained solid were as follows.

Immediately add about twice the amount of purified n- into the remaining THF solution while stirring.
Hexane was added dropwise, and the precipitate was further washed with n-hexane and dried at room temperature under nitrogen gas flow to obtain a yellow-green powder. The chemical analysis values (weight %) of the obtained solid were as follows.

Tic above! t,・,7TI(F 1,0coI,
The mixture was heat-treated at 20° C. for 3 hours under dry nitrogen gas flow to obtain purple powder o, t, i, , 51. The chemical analysis values (weight %) of the nine solids obtained were as follows.

(c) Preparation of vanadium trichloride ether complex/In a gross flask with a capacity of 100 ml, add dehydrated, deoxygenated THF k 0
0tntSVO1,20f? A small amount of magnesium ribbon particles with polished surfaces were supplied. - After boiling and refluxing for 70 hours with stirring, undissolved waste was filtered through a glass filter to obtain a reddish-brown solution.

THF was distilled from this solution to about half its volume, and cooled to 0°C with stirring. The precipitated reddish-orange fine particles were washed with purified n-hexane, and then dried at room temperature under nitrogen gas flow. The chemical analysis values (weight f/%) of the solid were as follows.

Examples/Mg c t! prepared in Production Examples (a) to (c).・8j
THF.

TiOt, -THF and VOt, -,7THF were weighed out in Jmmol, Ko, Commol and /I7 mmol, respectively, 300ml17) THF was added and stirred, and the transparent ether solution was immersed. From this ether solution, the following (a)
A powdery solid complex was obtained by the method described above.

a) A method in which THF is evaporated under a stream of purified nitrogen at about 0.degree. C. and the precipitated solid powder is dried under the same conditions.

b) Purification of tz A method in which an ether solution containing an ether complex is poured into n-hexane, the resulting precipitate is sufficiently washed with n-hexane, and then dried at room temperature.

Next, 3 t of purified n-hexane was charged into an rt autoclave, and 0.40 mmol of triisobutylaluminum (hereinafter abbreviated as AJ rather than 1-T) and 6 of the above powdered solid complex 301q were introduced. ? After raising the temperature to θ℃, the temperature is 1'4
Hydrogen was introduced until the total pressure reached 7.2. −
Polymerization was started by introducing ethylene until the amount reached Kg/-. Constant pressure polymerization was carried out for several hours while adding ethylene as needed to maintain a predetermined total pressure.

The obtained polymer was in the form of a white powder with high bulk density. The results are shown in Table-/.

Examples λ to D and Comparative Examples/ to 6 Each ether complex prepared in Production Examples (A) to (C) is shown in Table-
/And weigh the amount shown in Table 1, and use this! 00td of 'I'HF was added and stirred to obtain a clear ether solution.

A powdery solid complex was obtained from this ether solution by the method described in (,) or (1) above.

The polymerization was carried out under constant pressure polymerization for KJ time under the polymerization conditions shown in Table 1 and Table λ in the same manner as in Example. The results are shown in Table-/ and Table-1.

Example 10 Example! Ethylene polymerization was carried out in the same manner as in Example A, except that T W A O, lIO mmol was used instead of A θ and I10 mmol from T. Polyethylene 8otoy of FR-jj was obtained. The skin of the molded product was extremely smooth and the die swell was small.

Example // In the example, A θ from T, ri Om! In place of No. 1, 8 θmmol of diethylaluminum chloride
Ethylene polymerization was carried out in the same manner as in Example 7 except that polyethylene SDE01 of Mnie00-A and PR-7- was obtained. The skin of the molded product was extremely smooth.

〔Effect of the invention〕

According to the method of the present invention, it is possible to obtain with high efficiency an olefin having a high bulk density, a wide molecular weight distribution, and good processability in the high molecular weight region, and is therefore industrially useful.

Claims (1)

[Claims] (1) In a method for polymerizing olefins using a catalyst system consisting of a transition metal compound and an organoaluminum compound,
As a transition metal compound, the general formula, [Mgp・Tiq・V
r]
0, 5.5≦r/q≦57, 2<a≦3, 1≦n≦3. ), Mg atom, Ti atom, V atom,
A method for polymerizing olefins, characterized by using a solid complex composed of halogen atoms and ether molecules.