JPH01272605A - Production of ethylene polymer - Google Patents

Abstract

PURPOSE:To obtain in high efficiency the title polymer with broad molecular weight distribution, high in melt tension and great in die swell, using a catalyst made up of a titanium-contg. porous inorganic oxide carrier, a transition metal compound and aluminoxane. CONSTITUTION:A (co)polymerization, either of ethylene singly or between ethylene and an alpha-olefin is carried out in the presence of a catalyst made up of (A) a titanium-contg. porous inorganic oxide carrier prepared by heating at 300-1000 deg.C a porous inorganic oxide (e.g., silica, alumina >=50m<2>/g in specific surface area, >=50Angstrom in mean pore size and <=100mum in mean size), (B) a transition metal compound with conjugated pi electron-carrying group as ligand [e.g., bis(cyclopentadienyl)dimethyltitanium], and (C) aluminoxane [e.g., a compound of formula I or II (R<6> is 1-6C alkyl or halogen; R<7> is 1-6C alkyl; n>=1)].

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to a method for producing ethylene polymers using a novel catalyst system. More specifically, the present invention relates to a method for producing an ethylene polymer suitable for inflation molding, blow molding, etc., which has a wide molecular weight distribution, and has a large melt tension and die swell.

(2) Conventional technology Ethylene polymers are used as resin materials for various molded products.
Generally, they are widely used, and the required properties differ depending on the molding method and application.

For example, polymers with relatively low molecular weights and narrow molecular weight distributions are suitable for products molded by injection molding, whereas polymers with relatively low molecular weights and narrow molecular weight distributions are suitable for products molded by inflation molding, blow molding, etc. Polymers with high molecular weight and wide molecular weight distribution are suitable. Molecular weight distribution is related to the surface texture of films and blown products, and it is believed that the wider the molecular weight distribution, the less rough the surface of the molded product will be.

That is, even in the case of a polymer having a high molecular weight, a high-quality product can be obtained because it has good fluidity and does not cause melt fracture on the surface of the molded product. In addition, in inflation molding and blow molding, for example, when performing stable high-speed molding of blown film or ensuring the stability of parisons during blow molding, it is especially important to prevent parisons from sagging or tearing for large containers. 1
1-, it is necessary to select a polymer with high melt tension.

Previously, several methods have been proposed for producing ethylene polymers with a wide molecular weight distribution and high melt tension.
-90810, 59-56408.

Examples include eo-toesoe. Japanese Patent Publication No. 5 [i-90
809.

Although 58-90810 has an effect of improving die swell, the level of improvement is insufficient, and it cannot be said that the molecular weight distribution is sufficiently wide. Also, JP-A-59-
Although the melt tension of No. 56406 and No. 80-106806 can be controlled over a wide range, the breadth of the molecular weight distribution is somewhat insufficient, and there is room for improvement in the balance between the melt tension and the molecular weight distribution.

(3) Problems to be Solved by the Invention The purpose of the present invention is to improve the problems of the above-mentioned prior art.
The object of the present invention is to provide a method for efficiently producing an ethylene polymer having a wide molecular weight distribution, high melt tension, and die swell.

(4) Means for solving the problem Results of studies to achieve the above objective (A) A porous inorganic oxide carrying a titanium compound was heated at 300°C.
A titanium ternary porous inorganic oxide support obtained by heating in a temperature range of 1000°C to 1000°C, (B) a transition metal compound having a group having conjugated π electrons as a ligand, and (C) a catalyst formed from aluminoxane. By copolymerizing ethylene alone or ethylene and α-olefin in the presence of
The inventors have discovered that the above object can be achieved and have arrived at the present invention.

Component (B), which is a part of the constituent components of the catalyst of the present invention, and (C)
) components have recently been proposed, for example, JP-A-58-19309, 6m21+307°82
-230802 is exemplified, but all of these give polymers with a narrow molecular weight distribution. Also, JP-A-61-1
08810.61-276805.61-296008
゜63-22804, 63-54403, 63-6
1010 etc. are (B).

This catalyst is a combination of component (C) and a certain inorganic oxide carrier, and these also give a polymer with a narrow molecular weight distribution. The present invention achieves a wide molecular weight distribution and high This is surprising because it provides an ethylene polymer that has both melt tension and die swell, which was completely unexpected from conventional technology.

In the present invention, the titanium compound used for producing the carrier is a trivalent or tetravalent titanium compound. A specific example of a trivalent titanium compound is titanium trichloride, which is made by a hydrogen reduction method, or a solid solution or composition of titanium trichloride with various metals as a main component, especially made by an aluminum reduction method. T i C(l φ−AΩCΩ3
etc. Furthermore, products obtained by treating titanium trichloride with narcol or other electron-donating compounds can also be used.

Examples of the tetravalent titanium compound include the following compounds.

It is an aliphatic, alicyclic or aromatic hydrocarbon group having at most 8 carbon atoms, X represents a halogen atom, and g is 0.
The number is ≦g≦4. ), and preferred representative examples thereof include titanium tetrachloride, titanium tetrabromide, methoxytitanium trichloride, ethoxytitanium trichloride, propoxytitanium trichloride, butoxytitanium trichloride, dimethoxytitanium dichloride,
Examples include dibutoxytitanium dichloride, tributoxytitanium chloride, tetraethoxytitanium, tetraisopropoxytitanium, and tetrabutoxytitanium.

(Left below) (@General formula (where R2 is an aliphatic, alicyclic or aromatic hydrocarbon group having at most 8 carbon atoms, and m is an integer from 2 to 10.) This polytitanate is obtained by partially hydrolyzing titanium alkoxy compounds, and typical examples include jetoxytitanium dimer, jetoxytitanium trimer, dipropoxytitanium dimer, Examples include dipropoxytitanium tetramer, dibutoxytitanium tetramer, and dibutoxytitanium decamer.

(c) The titanium compounds shown in (a) and (2) above are treated with an electron-donating compound, and the electron-donating compound has at least one polar group, and representative examples of preferred ones are ether compounds. , carboxylic acid compounds, alcohol compounds, or ester compounds.

Among these titanium compounds, tetraalkoxytitanium is particularly preferred. Porous inorganic oxides are found in Periodic Table 11a.
Examples include silica, alumina, magnesia, zirconia, or mixtures thereof. These oxides have different properties depending on their type and manufacturing method, but those preferably used in the present invention have a specific surface area of 50 d/g or more, an average pore diameter of 50 λ or more, and an average particle size of 100 d/g or less. It is. A method for supporting a titanium compound on a porous inorganic oxide is a method in which the titanium compound is dissolved in an inert solvent and then impregnated and supported by mixing the inorganic oxide with this solution, or a method in which the titanium compound is supported in the absence of an inert solvent. There are a contact method and a dry mixing method using a ball mill or the like. The supporting temperature is generally 100°C or less, preferably 0 to 40°C. If a solvent is used, the titanium compound supported porous inorganic oxide thus obtained is heated in a temperature range of 300°C to 1000°C after distilling off the solvent. A carrier is obtained. Heating is done using dry gas (
It is possible to perform IjJ in a fluidized state by, for example, air. The ratio of the titanium compound to the porous inorganic oxide is preferably such that the content of titanium atoms in the resulting carrier is in the range of 0.5% to 10% by weight.

As a transition metal compound using a group having conjugated π electrons as a ligand of the catalyst component (B), for example,
This is a compound represented by MR'R5. Here, M is titanium, zirconium, or phenol, R3 is a cycloalkagenyl group, and R4 and R5 are each a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, a halogen atom, or a hydrogen atom. . R8 is a group that connects two R3s, is an alkylene group having 1 to 4 carbon atoms, and p is 0 or 1. The cycloalkagenyl group is, for example, a cyclopentagenyl group, a methylcyclopentagenyl group, a pentamethylcyclopentagenyl group,
Examples include indenyl group and tetrahydroindenyl group.

Specific examples of the hydrocarbyl group for R4 and R5 include methyl, ethyl, propyl, butyl, amyl, isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl, phenyl, and the like. can. Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, etc., and examples of the halogen atom include chlorine, bromine, fluorine, etc.
Bis(cyclopentagenyl)dimethyltitanium, bis(methylcyclopentagenyl)dimethyltitanium, bis(pentamethylcyclopentagenyl)dimethyltitanium, bis(cyclopentagenyl)methylchlorotitanium, bis(cyclopentagenyl) ) dichlorotitanium, bis(indenyl)dimethyltitanium,
Bis(indenyl)dichlorotitanium, ethylenebis(indenyl)dichlorozirconium, ethylenebis(
Tetrahydroindenyl)dichlorozirconium, bis(cyclopentajenyl)dimethylzirconium, bis(methylcyclopentagenyl)dimethylzirconium, bis(pentamethylcyclopentagenyl)dimethylzirconium, bis(cyclopentagenyl)methylchlorozirconium , bis(cyclopentagenyl)dichlorozirconium, bis(indenyl)dimethylzirconium, ethylenebis(indenyl)dichlorozirconium, ethylenebis(tetrahydroindenyl)dichlorozirconium, bis(indenyl)dichlorozirconium, bis(cyclopentagenyl) Examples include dimethylhafnium and bis(cyclopentagenyl)dichlorohafnium.

As the aluminoxane of the catalyst component (C), the -killing% formula %) (in the formula, R6 is an alkyl group having at most 6 carbon atoms or a halogen atom, and R7 is an alkyl group having at most 6 carbon atoms) When R6 is an alkyl group, it is the same as R6, and n is an integer of 1 or more.) or a mixture thereof. R6 is, for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc., preferably a methyl group or an ethyl group, and particularly preferably a methyl group. Aluminoxane can be easily produced by gradually adding a predetermined amount of water to an organoaluminum compound dissolved in an inert hydrocarbon solvent such as toluene, and heating it slightly if necessary. It can also be carried out using crystal water such as aluminum sulfate hydrate or aluminum sulfate hydrate.

The catalyst of the present invention is formed by contacting catalyst component (A), catalyst component (B) and catalyst component (C). The order in which these components are brought into contact is not particularly limited;
For example, these three components may be brought into contact at the same time, or
The catalyst component (A) and the catalyst component (B) may be brought into contact with each other in advance, and then the catalyst component (C) may be brought into contact with each other. The ratio of these three components used is usually 1 part of the catalyst component (A).
0.01 ml to 1 ml of catalyst component (B) per g
mmol, preferably 0.02 to 0.4 nu
It is nol. The proportion of catalyst component (C) to be used is usually such that the amount of aluminum in catalyst component (C) is in the range of 1 to 105 g atoms, preferably 10 to 1 mol of catalyst component (B).
It is in the range of 0' g atoms.

The polymerization of the present invention can be achieved by homopolymerizing ethylene or copolymerizing ethylene and α-olefin using the catalyst formed as described above. The α-olefin used when copolymerizing with ethylene has at most 20 carbon atoms, preferably 12 carbon atoms.
Typical examples include propylene, butene-1, hexene-1,4-methylpentene-1, and octene-1.

The proportion of the α-olefin in the resulting ethylene copolymer is generally preferably 20 mol% or less, particularly preferably 15 mol% or less.

In carrying out the method of the present invention, the polymerization method is as follows:
Liquid phase polymerization methods such as slurry polymerization and solution polymerization, gas phase polymerization, etc. are possible. The liquid phase polymerization method is usually carried out in a hydrocarbon solvent, and hydrocarbon solvents include butane, isobutane, hexane, octane, decane, cyclohexane,
Inert hydrocarbons such as benzene, toluene and xylene may be used alone or in mixtures. Polymerization temperature is generally 0℃
~300°C, and practically 20~200°C.

Further, if necessary, hydrogen or the like may be allowed to coexist in the polymerization reaction system in order to adjust the molecular weight.

Next, the present invention will be explained in more detail by giving Examples and Comparative Examples.

In the Examples and Comparative Examples, the melt index (hereinafter referred to as rMIJ) was measured according to JISK-6760 at a temperature of 190° C. and a load of 2.16 kg. Also, No\I Road Melt Index (
HLMIJ (hereinafter referred to as HLMIJ) was measured according to JIS K-6780 at a temperature of 190°C and a load of 21.6 kg.The value obtained by dividing HLMI by Ml, that is, HLM
The higher the I/Ml value, the broader the molecular weight distribution.

The melt tension was measured using a melt tension tester manufactured by Toyo Seiki ■, with a resin temperature of 190°C and an orifice diameter of 2.1 mm.
Orifice length 811111 Extrusion speed 15mm/ak
The measurement was performed under the conditions of in-winding and a speed of 8.5 m/min.

The die swell was expressed as the expansion degree (96) of the outer diameter of the extrudate relative to the orifice diameter (2, l+am) at the time of MI measurement using the same equipment as MI.

(5) Examples Example 1 Preparation of catalyst component (A) Silica (W, R, Grace Co, Daviso
952) dried at 150℃, 300 g
100 ml of n-hexane and 13.2 g of tetraisopropyl titanate were added to a 100 ml three-meter flask, and the mixture was stirred at room temperature for 30 minutes. From the obtained slurry, n-hexane was distilled off under reduced pressure at 40°C.

The obtained powder was placed in a cylindrical firing electric furnace (diameter 38 mm, with a perforated plate type), and first the linear velocity was increased to 401 using nitrogen gas.
The temperature was increased at a rate of 90° C./hr at a flow rate of 11/see. When the temperature reached 600° C., the nitrogen was replaced with air, and the mixture was fired at this temperature for 8 hours while flowing at the same linear velocity, and then the atmosphere was replaced with nitrogen and the temperature was lowered to room temperature. As a result, a 20f carrier was obtained. Elemental analysis of this carrier revealed that it contained 5.5% by weight of titanium atoms.

Preparation of catalyst component (C) Place 100 a+ol of copper sulfate pentahydrate in a 300 ml Mitsuroh flask purged with nitrogen, and add toluene loOm.
It was suspended in l. Then trimethylammonium 300
mmol was added at 30° C. and the reaction continued at that temperature for 48 hours. Then, this reaction product was filtered to obtain a solution of the reaction product. When toluene was distilled off, 8.
2 g of white crystalline methylaluminoxane was obtained.

Polymerization of ethylene Into a 3L autoclave that was sufficiently purged with nitrogen, 2 g of isobutane, 0.2 g of the carrier obtained above, 2.0 maol of a toluene solution of methylaluminoxane, and 0.01 ml of a toluene solution of biscyclopentadienyl dichlorozirconium were charged. , the internal temperature was raised to 90°C. Next, hydrogen was added at a gauge pressure of 2 kg/c, and ethylene was further pressurized, and polymerization was carried out for 1 hour while maintaining the ethylene partial pressure at 1.0 kg/c. Polymerization was then terminated by discharging the contained gas to the outside of the system.

As a result, 186 g of white powdery polymer was obtained. The Ml of this polymer is 0.54 (g/10a+In)
, HLMI is 74 (g/10m1n) and H
LMI/Ml was 137, and the molecular weight distribution was wide. Also, the melt tension is 85% for 35g 1 die well.
Met.

Comparative Example 1 In place of titanium-supported silica in Example 1, Dav
Ethylene polymerization was carried out in exactly the same manner as in Example 1, except that Ison 952 silica calcined at 600°C was used and the hydrogen partial pressure was changed to 0.2 kg/c+#. The obtained polymer weighed 148 g and had an M I -0.82 (g/
10m1n), HLMI/MI-20,4 with ivy. Further, the melt tension was 2.5 g and the die swell was 20%.

Examples 2 to 4 Catalyst component (A) was prepared in the same manner as in Example 1, except that the amount of tetraisopropyl titanate used in Example 1 was changed as shown in Table 1. Polymerization of ethylene was carried out. The results are shown in Table 1.

Examples 5 to 8 The catalyst components (
^) was prepared, and ethylene polymerization was performed in the same manner as in Example 1. The results are shown in Table 1.

Examples 9 to 13 Ethylene polymerization was carried out in the same manner as in Example 3, except that the compounds shown in Table 2 were used instead of biscyclopentadienyldichlorozirconium as the transition metal compound. The results are shown in Table 2.

Example 14 Copolymerization of ethylene and butene-1 In a 3 g autoclave that was sufficiently purged with nitrogen, isobutane 21, 0.2 g of the catalyst component (A) prepared in Example 3,
2.0 mmol of methylaluminoxane toluene solution
Add a toluene solution of biscyclopentadienyl dichlorozirconium to 0.0 Ian + ol, and bring the internal temperature to 75.
The temperature was raised to ℃. Next, 80 g of butene-1 was charged, hydrogen was added at 0.3 kg/cd, and ethylene was further pressurized, and polymerization was carried out for 1 hour while maintaining the ethylene partial pressure at 1 kg/c+ff. As a result, 225 g of white polymer was obtained. This polymer has an M I -0,75 (g
/ 10m1n), aLMx-42 (g/1Iin)
, HLMI/M! -56, density -0,925 (g/
ml), melt tension isg, die swell is 58
%Met.

Example 15 In a 300 ml Mituro flask purged with nitrogen, 1 g of the catalyst component (A) prepared in Example 1 and 20 ml of toluene were added.
and a toluene solution of methylaluminoxane in lon+
mol was added and stirred at room temperature for 1 hour. Next, 0.05 cm of biscyclopentadienyl dichlorozirconium
ol was added, and stirring was further continued for 1 hour.

A solid catalyst component was obtained by distilling off toluene under reduced pressure.

Copolymerization of ethylene and butene-1 2 g of isobutane in a 3 g autoclave purged with nitrogen,
Charge 0.3g of the solid catalyst component obtained above and adjust the internal temperature to 75°C.
The temperature rose to . Next, 65 g of butene-1 was charged, 0.4 kg/c of hydrogen was added, and ethylene was further pressurized, and polymerization was carried out for 1 hour while maintaining the ethylene partial pressure at I kg/clj.

As a result, 198. A polymer of MI-1,1 (
g/10a+in), HLM I-69,5 (g/l
oo+in), HLMI/MI-63,2 and density-
It was 0,936 (g/ml). Also, the melt tension is 21
g, die swell was 67%.

(The following is a blank space) (6) As described in detail, the method for producing an ethylene polymer of the present invention has a wide molecular weight distribution, high melt tension, and large die swell. It can be manufactured efficiently.

Therefore, a high quality ethylene polymer suitable for film molding and blow molding can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of catalyst preparation in the production method of the present invention.

Claims (1)

[Claims] 1. (A) A titanium-containing porous inorganic oxide support obtained by heating a porous inorganic oxide on which a titanium compound is supported in a temperature range of 300°C to 1000°C (B) Conjugated An ethylene-based polymer characterized by copolymerizing ethylene alone or ethylene and an α-olefin in the presence of a transition metal compound having a group having π electrons as a ligand and a catalyst formed from (C) aluminoxane. Method of manufacturing coalescence.