JPS6369807A - Production of ethylene copolymer - Google Patents

Abstract

PURPOSE:To obtain a polymer having excellent mechanical properties and moldability, etc., by copolymerizing ethylene with an alpha-olefin at a specific temperature in the presence of a catalyst derived from a Ti compound and a reaction product of a dialkylmagnesium and an organic Al compound. CONSTITUTION:Ethylene is made to react with a 5-6C alpha-olefin and a 8-18C alpha-olefin at >=155 deg.C in the presence of a catalyst derived from (A) a reaction product of a dialkylmagnesium of formula I (R<1> and R<2> are 1-18C alkyl or cycloalkyl) (e.g. dibutylmagnesium, butyloctylmagnesium, etc.) and an organic Al compound (e.g. ethylaluminum sesquichloride) and (B) a Ti compound of formula II (R<3> is 1-10C alkyl, cycloalkyl, aryl or aralkyl; X is halogen; 0<=n<=4) (e.g. TiCl4).

Description

Detailed Description of the Invention [Industrial Application Field] This invention relates to ethylene, α-olefins having 5 to 6 carbon atoms, such as pentene-1, hexene-1, etc., and carbon atoms having 8 carbon atoms.
Regarding the production method of ethylene copolymer with α-olefin of ~18, for example, octene-1, etc., in more detail, a polymer with excellent mechanical properties, moldability, transparency, etc., and the presence of a catalyst with high polymerization activity. The present invention relates below to a method for producing an ethylene copolymer that can be produced with a high polymer yield.

[Conventional technology and its problems]

Conventionally, as a method for producing ethylene copolymers such as linear low-density polyethylene (LLDPE), a method of performing high-temperature solution polymerization in the presence of a catalyst obtained from an organomagnesium compound, a titanium compound, and an organoaluminum compound (
Japanese Patent Publication No. 60-11925, Japanese Patent Application Publication No. Sho BO-4240
No. 5, etc.) are known.

By the way, in general, in solution polymerization, the two-product polymer is dissolved in the solvent, and the liquid viscosity in the polymerization system becomes high. .

However, all the catalysts used in conventional known methods have insufficient activity at temperatures above 155°C, and the physical properties of copolymers obtained by conventional high-temperature solution polymerization are still unsatisfactory. There is a problem.

[Purpose of the invention]

This invention has been made based on the above circumstances.

That is, an object of the present invention is to provide a method for producing an ethylene copolymer that has excellent properties such as mechanical properties, moldability, and transparency by increasing catalytic activity.

[Means for achieving the above purpose]

In order to achieve the above object, as a result of intensive research by the present inventor, a catalyst obtained by specifically selecting dialkylmagnesium from among magnesium compounds and bringing it into contact with an organoaluminum compound and a titanium compound in a specific order is obtained. Its activity is high, and using such a catalyst, ethylene and α-olefins having 5 to 6 carbon atoms and 8 to 18 carbon atoms can be used.
When copolymerized with α-olefin, the resulting copolymer has excellent mechanical properties such as film impact strength and moldability.

This invention was achieved by discovering that it has excellent properties such as transparency.

That is, the gist of the present invention for achieving the above object is that dialkylmagnesium H+H2Mg represented by the formula (1)...
(1) (However, in the formula (1), 1(+, l (2 represents an alkyl group having 1 to 18 carbon atoms and a cycloalkyl group, respectively) and an organoaluminum compound, and
) Titanium compound Ti (OR3) n X a-n -----(2)(
However, in formula (2), R3 represents an alkyl group, cycloalkyl group, aryl group, or aralkyl group having 1 to 10 carbon atoms, X represents a halogen atom, and n is 0≦n
It is a real number satisfying ≦4. ) in the presence of a catalyst obtained from
This is a method for producing an ethylene copolymer, which is characterized by copolymerizing an α-olefin of No. 6 and an α-olefin having 8 to 18 carbon atoms.

Specific examples of the dialkylmagnesium represented by the above formula (1) include diethylmagnesium, dibutylmagnesium, butyloctylmagnesium, cyamylmagnesium, dihexylmagnesium, dioctylmagnesium, ethylbutylmagnesium, butylisopropylmagnesium, etc. Among these, dibutylmagnesium, dihexylmagnesium, butyloctylmagnesium, etc. are preferred. Further, in the present invention, if a magnesium compound other than the dialkylmagnesium represented by formula (1), such as magnesium chloride, is used, sufficient catalytic activity cannot be obtained.

There are various types of organoaluminum compounds, but compounds having at least one aluminum-carbon bond in the molecule are usually used.
3Ai, R42Ai X2, R4AuX22, R'
2AiOR5, R4An (OR5)X2, R43AJ
L2X23 (in the formula, R4 and R5 each represent an alkyl group or an aryl group having 1 to 20 carbon atoms,
X? indicates l\rogen atom. ) can be mentioned. A suitable example of this organic aluminum is Teha,
Examples include diethylaluminum monochloride, diisopropylaluminum monochloride, diimbutylaluminum monochloride, dioctylaluminum monochloride, ethylaluminum dichloride, isopropylaluminum dichloride, ethylaluminum sesquichloride, and among these, R4
Preferred are, for example, ethylaluminum sesquichloride, represented by 3AJL2 X23, and diethylaluminium monochloride, represented by R'2AjLX2.

In the production method of the present invention, the reaction product of the dialkylmagnesium and the organoaluminum compound [
Hereinafter, this reaction product may be abbreviated as component (A). ] and a titanium compound represented by the above formula (2) [Hereinafter, this titanium compound may be abbreviated as component (B). ] Use a catalyst obtained from

The component (A) can be obtained by adding the dialkylmagnesium and the organoaluminum into an inert solvent and bringing them into contact at, for example, a temperature of -40 to 240°C.

Examples of the inert solvent include aliphatic hydrocarbons having 5 to 16 carbon atoms, alicyclic hydrocarbons, aromatic hydrocarbons, etc., and specific examples include normal- or iso-pentane, hexane, heptane, and octane. , nonane, decane, tetradecane or cyclohexane, as well as benzene, toluene, xylene and the like. Moreover, the above-mentioned various hydrocarbons can be used alone as this inert solvent. Preferred inert solvents include, for example, n-hexane.

Specific examples of the component (B) include tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, tetracyclohexoxytitanium, and tetraphenoxy titanium. Tetraalkoxytitanium represented by the general formula Ti (OR3) a such as titanium: TiC14, TiBr4. General formula TiX such as TiI4
Tetrahalogenated titanium represented by n; (J:H30)Ti0mon3, (02H50)Ti
Cu3, (G3 H70)TiCJ13. (n-C4
H9) TiCJL3, CG2 H5) Trihalogenated alkoxytitanium such as TiBr3: (CH30) zTic? , (07H50)2 Tic
2, (C3HrO)2Ti C12, (n-C4H9
0) 2.7i (42, (02H50)?Ti 0 sentence 2 etc. dihalogenated titanium; (CH30)3TiC, (0
2850) 3 TiC standing.

(03H2O)3Ti(41,Cn-C4H90)3T
Examples include monohalogenated titanium such as ic1.

Among these, tetraalkoxytitanium represented by the general formula Ti (OR3)a and tetrahalogenated titanium represented by TiXn are preferred, particularly tetra-n-
Butoxytitanium and tetrachlorotitanium are preferred,
These various titanium compounds may be used alone, or two or more of the above may be used in combination.

The catalyst in the method of this invention is the above-mentioned (A) and (B).
The main ingredients are: That is, the main components are a reaction product (A) of dialkylmagnesium and an organoaluminum compound and a titanium compound (B). Here, without preparing the component (A) in Section 2 in advance,
For example, even if an organoaluminum compound and a titanium compound are reacted and then brought into contact with dialkylmagnesium,
The activity of the resulting catalyst is not improved.

When preparing a catalyst by mixing component (A) and Ji component (B), the ratio of each metal in the catalyst is magnesium/titanium (atomic ratio) -0.1 to 30. Preferably 0
．． 5-20, aluminum/titanium (atomic ratio) = 1-1
It is desirable to adjust it to 20, preferably 5 to 80. If the atomic ratio of magnesium/titanium is out of the above range, the catalyst activity may decrease. Further, if the atomic ratio of aluminum/titanium is less than 1, the activity of the catalyst will be low, and conversely, if it exceeds 120, no improvement in activity corresponding to the amount added will be observed. Furthermore, outside the above range, the physical properties of the resulting copolymer, especially film formability, deteriorate.

According to the method of the present invention, copolymerization of ethylene, an α-olefin having 5 to 6 carbon atoms, and an α-olefin having 8 to 18 carbon atoms is carried out in the presence of the catalyst and at a temperature of 155°C or higher. proceed.

Examples of the α-olefin having 5 to 6 carbon atoms include pentene-11hexene-1,3-methylpentene-1,4-methylpentene-1.

In this invention, any one or both of the α-olefins 4[15[5 to 6] may be used simultaneously.

Examples of the α-olefin having 8 to 18 carbon atoms include linear monoolefins such as octene-1, nonene-1, decene-1, undecene-1, and dodecene-1, 2-ethyl-hexene-1, 2, Examples include branched olefins such as 2,4-trimethyl-pentene-2, and further styrene. Among these, the linear monoolefins mentioned above are particularly preferred.

A preferred combination of raw materials used in the reaction of this invention is ethylene, 1-hexene, and 1-octene.

When copolymerizing ethylene, the α-olefin having 5 to 6 carbon atoms, and the α-olefin having 8 to 18 carbon atoms,
The resulting linear low-density polyethylene has an ethylene unit content of 80 to 99.2 mol%, a C5-6 α-olefin unit content of 0.4 to 9.6 mol%, tJ
When the raw material mixture is supplied so that the unit content of α-olefins with e element Ik 8 to 18 is 0.4 to 9.6 mol%, the density o, sto ~ 0.940 g/c
m3 especially 0.910-0.938 g/cm3. Melt index (Ml) 0.1-10 g/10 min, especially 0.5-5 g
/10 minutes, melt flow ratio (MFR=flow rate/melt index) 1
Linear low density polyethylene having a molecular weight of 8 to 52, particularly 23 to 48, can be suitably produced. In addition, when the MI of the ethylene copolymer is less than 0.1 g/10 min or the MFR is less than 18, moldability may deteriorate. Furthermore, if the MI is greater than 10 g/10 min or the MFR is greater than 52, the film impact strength and transparency may deteriorate.

The polymerization conditions in this invention cannot be generalized depending on the physical properties of the desired polymer, the type of monomer, etc., but usually the catalyst concentration is 0.001 to 1 in terms of titanium concentration.
It is 0 mmol/vertical, preferably 0.01 to 1.0 mmol/vertical. The reaction temperature is 155°C or higher, especially 180~
2200°C, which is the most preferable temperature for device operation since the liquid viscosity of the produced polymer solution decreases, and the reaction pressure is 1.
0-150 Kg/rn', especially 20-7oKg/rn'
Furthermore, this polymerization reaction may be carried out in the presence or absence of an inert solvent. Furthermore, a molecular weight regulator such as hydrogen may be present in the polymerization reaction system. Examples of the active solvent include the aforementioned aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and the like.

〔Effect of the invention〕

According to the method of the present invention, (1) Since a catalyst obtained by contacting and reacting a dialkylmagnesium, an organoaluminum compound, and a titanium compound in a specific order is used, the catalyst has catalytic activity at a temperature of 155°C or higher. As a result, the polymer yield can be increased; (2) the viscosity of the produced polymer solution can be lowered, which is favorable for equipment operation; and (3) the resulting copolymer It is possible to provide a method for producing an ethylene copolymer having various excellent advantages such as, for example, excellent mechanical properties such as film impact strength, moldability, and transparency.

〔Example〕

Next, the present invention will be explained in more detail by showing examples and comparative examples of the present invention.

(Examples 1 to 8) In a 1M continuous polymerization vessel, 7.4 g of dehydrated n-hexane was added.
Mj/hour, titanium compound 0.25 mmol/hour,
Dialkylmagnesium and organoaluminum compounds were fed in the proportions shown in Table 1 and as shown in FIG. At the same time, 1300 g/hour of ethylene, 0.15 g/hour of hydrogen, and comonomer were continuously supplied at the rates shown in Table 1, and the reaction temperature was 175°C and the reaction pressure was 0 kg/m''G.
．． A polymerization reaction was carried out for 11 hours to obtain an ethylene copolymer. The results are shown in Table 1.

(Comparative Example 1) The same procedure as in Example 3 was carried out except that each component was separately supplied to the polymerization vessel.

The results are shown in Table 1.

(Comparative Example 2) The same procedure as in Example 3 was carried out except that the titanium compound and the organoaluminum compound were reacted and then brought into contact with the dialkylmagnesium. The results are shown in Table 1.

(Comparative Example 3) The same procedure as in Example 4 was carried out except that each component was separately supplied to the polymerization vessel.

The results are shown in Table 1.

(Comparative Example 4) 10 mol of anhydrous magnesium chloride was dehydrated in a nitrogen stream.
The suspension was suspended in 30 g of hexane, 60 mol of ethanol was added dropwise under stirring, and the mixture was reacted at 30° C. for 1 hour. Thereafter, 27 mol of diethylaluminium chloride was added dropwise to the mixture and stirred, and 30 mol of titanium tetrachloride was added thereto, followed by reaction at 80° C. for 3 hours to obtain a solid catalyst component.

The obtained solid catalyst component was fed at 0.25 mmol/hour in terms of titanium, and diethylaluminum chloride at 16 mmol/hour. At the same time, 1300 g/hour of ethylene, 0.15 g/hour of hydrogen, and comonomer were continuously supplied at the rates shown in Table 1, reaction temperature was 175°C, and reaction pressure cuff was 0 kg.
/rn''G for 0.11 hours to obtain an ethylene copolymer. The results are shown in Table 1.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the state of supply of each component of the catalyst used in the ethylene copolymer production method of the present invention.

Claims (1)

[Claims] (1) Dialkylmagnesium R^1R^2Mg represented by formula (1) (1) (However, in formula (1), R^1 and R^2 each have a carbon number of 1 to 18 ) and an organoaluminum compound and the reaction product of the
) Titanium compound Ti(OR^3)_nX_4_-_n…………(2)(
However, in formula (2), R^3 represents an alkyl group, cycloalkyl group, aryl group, or aralkyl group having 1 to 10 carbon atoms, X represents a halogen atom, and n is 0≦
It is a real number satisfying n≦4. ) in the presence of a catalyst obtained from
A method for producing an ethylene copolymer, which comprises copolymerizing an α-olefin having 6 to 6 carbon atoms and an α-olefin having 8 to 18 carbon atoms.