JPS60240708A - Production of polyolefin - Google Patents

Abstract

PURPOSE:To produce a polyolefin of good powder properties by controlling the formation of grease and wax as by-products, by using a catalyst system comprising a polyethylene-coated solid catalyst component and an organoaluminum compound. CONSTITUTION:A solid catalyst component containing Mg, Ti, and a halogen (e.g., a reaction product among an oxygen-containing organomagnesium compound, an oxygen-containing organotitanium compound and an aluminum halide compound) is immersed in a hydrocarbon solvent containing about 1-30wt% polyethylene. This system is heated to about 120 deg.C with stirring to dissolve the polyethylene in the solvent. The obtained solution is cooled to about 80 deg.C (at a rate of temperature fall of about 0.2-10 deg.C/min) to coat the surface of the solid catalyst component with about 0.1-500pts.wt., per pt.wt. of the catalyst component, precipitated polyethylene. Next, an olefin is polymerized according to a usual method by using a catalyst prepared by combining the above solid catalyst component with an organoaluminum compound.

Description

[Detailed description of the invention] [Industrial application field] The present BA relates to a method for producing polyolefins.

More specifically, the present invention relates to a method for producing polyethylene that produces little by-product grease and has good powder properties.

[Conventional technology]

Generally, when high-density polyethylene or low-strength polyethylene is produced by slurry polymerization using a Ziegler catalyst, the catalyst is directly introduced into the polymerization system without pretreatment to produce polyethylene or ethylene copolymer. , the following problems arise.

(1) It is difficult to obtain polyethylene or ethylene copolymer having favorable slurry properties. In particular, it is difficult to obtain a slurry with a high bulk density, which is relevant to productivity. This tendency is particularly remarkable when producing an ethylene copolymer, and the lower the WI degree is, the greater the decrease in bulk density is.

+21 Low molecular weight polymers and copolymers are easily dissolved in the polymerization solvent, resulting in increased viscosity of the polymerization solution and adhesion to the walls of the polymerization vessel, making long-term continuous operation impossible), significantly reducing productivity.

(3; The catalyst component becomes solubilized in the polymerization solvent, resulting in the formation of whisker-like polyethylene and adhesion to the walls of the polymerization vessel, which leads to long-term continuous operation.

Various proposals have been made to improve these drawbacks. For example, a method in which a certain amount of prepolymerization is carried out in advance prior to single polymerization (Japanese Patent Application Laid-open No. 5S-TTTR,
Tokukai Show 1! -1r6gθ book patent publication Showa 3! ;-90jt/!
, JP-A-57-1qlda07, etc.)-! In addition, a method in which prepolymerization is carried out with goomethylpentene-7 (% Kaishos 5-i
to4Ii3) is one example.

[Problem that the invention seeks to solve]

However, in all of these methods, the density is 0.969/d.
) It is effective for the first time when producing low-density copolymers under J, and in experiments conducted by the inventors, no effect was observed at densities of 0.94 Iki/cd or higher. In particular, ethylene homopolymerization showed no effect at all.

By the way, even in high-density regions and homopolymerization, the formation of solvent-soluble polymers is a serious problem. In particular, due to requirements for product quality and processability, low molecular weight (viscosity average molecular weight = i4oo) is mainly used for multi-stage polymerization.

-41QOOO), there are many solvent-soluble low molecular weight polymers even if the density is high, and various problems as mentioned above arise. Furthermore, copolymers with a density of 0.941 kpl or less are in a special field called medium density polyethylene or linear low density polyethylene, and are not produced in large quantities.

Currently, density 0 is industrially useful and produced in large quantities.
4<j~0.970. Therefore, it is industrially important to maintain high productivity stably over a long period of time in production in this density range, including homopolymerization, to suppress the production of unnecessary by-products, and to minimize the loss of raw ethylene.
I am very much in favor of M.

From this point of view, the method using the prepolymerization has a density o, q e
The fact that it is only effective for copolymers with a molecular weight of s or less can be said to be a fatal drawback.

[Means for solving problems]

In order to solve the above-mentioned problems, the present inventors have conducted various studies and found that a specific solid catalyst component is pre-dissolved in polyethylene in the presence of the same catalyst in a hydrocarbon solvent, and subjected to reprecipitation treatment. Furthermore, by using a solid catalyst component seeded with a specific amount of polyethylene as a polymerization catalyst, the amount of solvent-soluble polymer can be reduced not only in low-density regions but also in high-density regions including homopolymerization.

It was discovered that polyethylene with good powder properties could be obtained, leading to the present invention.

That is, 1. The gist of the present invention is the homopolymerization of ethylene or the co-polymerization of ethylene with other α-olefins using a catalyst system consisting of a solid catalyst component containing (al) magnesium, titanium and a halogen, and (bl) an organoaluminum compound. When performing polymerization, the solid catalyst component (al) is precipitated with polyethylene in a hydrocarbon solvent, and the solid catalyst component (al unit weight f parts is θ./-100 Mk parts). The present invention relates to a method for producing a polyolefin, characterized in that a polyolefin coated with polyethylene is used.

Further, to describe the present invention in detail, the catalyst system used in the present invention is a catalyst system consisting of a solid catalyst component containing magnesium, titanium, and halogen as a transition metal compound component, and an organoaluminum compound.

Examples of the solid catalyst component containing magnesium, titanium, and halogen include the following solid catalyst components (a) to (f).

(a) A hydrocarbon-insoluble solid product obtained from a reaction mixture of a solid complex consisting of a magnesium halide, a titanium halide, and an electron donor and an organoaluminum compound (b) An oxygen-containing organic compound of magnesium and oxygen of titanium Reaction product between containing organic compound and aluminum halogen compound←1 Reaction product between magnesium oxygen-containing organic compound, titanium oxygen-containing organic compound, and silicon halogen compound) Magnesium oxygen-containing organic compound and titanium halogen compound Reaction product (e) Reaction product obtained by contacting a titanium compound with a solid reaction product of boron 8 Alcolade and a Grignard reagent (e) Treating a magnesium-containing solid with an oxygen-containing organic compound of boron Reaction products between the solid obtained by the reaction and the titanium compound. Magnesium compounds used in the preparation of these solid catalyst components include magnesium dihalides, alkoxymagnesium, allyloxymagnesium, alkoxymagnesium halides, and Grignard reagents. preferable.

Further, as the titanium compound, trivalent or tetravalent titanium halide, alkoxy titanium, alkoxy titanium halide, etc. are preferable.

As the aluminum halogen compound, alkyl aluminum dichloride, alkyl aluminum sesquichloride, dialkyl aluminum monochloride, etc. are preferable.

As the silicon halide, silicon tetrahalide, silicon alkyl trihalide, silicon allyl trihalide, silicon dialkyl dihalide, etc. are used.

As the boron compound, boron alcoholade or boron tetragenide alcoholade is used.

Further, as the electron donor used in the solid catalyst component (al), Vi, ether, carboxylic acid ester, alcohol, amine, etc. are used.

The solid catalyst components (a) to (f) are prepared using the raw materials as described above, and the preparation method is, for example, 4v Nashō, tA-9.
1t here, Tokukai Sho 3 Otsu-6igot, Tokugan Sho, tj-6
144 is also JP-A-36-22301. Patent application 1976-114
The method described in JP-A No. 1219/1983-069 is suitable.

To explain in more detail one example of the method for producing the above-mentioned solid catalyst component, the magnesium compound has the general formula MJ (OR
”) mXI-In (where R1Fi represents an aryl or cycloalkyl group, rFi represents a halogen atom, and %m is ! or -) is used. Specifically, R1 is methyl, ethyl, propyl,
Butyl, pentyl.

Hexyl, octyl, phenyl, tolyl, xylyl, cyclohexyl and other alkyl, aryl, cycloalkyl groups up to the order of carbon number/j), compounds such as chlorine, bromine or iodine, such as dimethoxymagnesium, Examples include toxymagnesium, ethoxymagnesium chloride, diphenoxymagnesium, and the like. Among these, compounds in which m in the general formula is co are preferred. Among them, jetoxymagnesium is most suitable.

On the other hand, a titanium compound has the general formula Ti(OR).

Kari-n (wherein Hs represents an alkyl, aryl or cycloalkyl group, X''H]h rogen atom, n I
d i, s or 3. ) is used. Examples of R1, Dichlorotitanium etc.;
Compounds where n is 3 include triethoxymonochlortitanium, tri-n-propoxymonochlortitanium, tri-n-butoxymonochlortitanium, etc.; compounds where n is 7 include ethoxytrichlortitanium, n-globoxytrichlortitanium , n-butoxytrichlortitanium is extracted. Among these, those where n is 3 or , particularly those where n is 3 are preferred. Among them, tri-n-butoxymonochlorotitanium is most suitable.

In the method of the present invention, first, a homogeneous hydrocarbon solution containing the above-mentioned magnesium compound and titanium compound is prepared. Examples of the hydrocarbon used as a solvent include aliphatic hydrocarbons such as hexane and hepta-7, alicyclic hydrogen ash such as cyclohexane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

To prepare a hydrocarbon solution, it is preferable to mix a magnesium compound and a titanium compound in advance to prepare a homogeneous liquid. Depending on the type of compound used, a homogeneous liquid can be achieved by simply mixing the above two components and heating, but if it is difficult to produce a homogeneous liquid, it is preferable to include alcohol. Alcohol solutions include ethyl alcohol, n-j lobil alcohol, n-7
Examples include "tyl alcohol, n-pentyl alcohol% n-octyl alcohol, etc. The order of mixing the two components is not particularly limited and may be arbitrary. After mixing, preferably /
A uniform liquid or a uniform alcohol solution can be obtained by heating to θO°C to /70°C.

Next, a hydrocarbon solvent is added to form a hydrocarbon solution.

In the method VC of the present invention, the hydrocarbon solution obtained as described above is mixed with the general formula A/R7 , l represents the number l≦l≦) to prepare a hydrocarbon-insoluble solid. As the general formula ()jl and XI of the organic aluminum halide compound, those exemplified above for R1 and F can similarly be mentioned. Specific examples include methylaluminum dichloride, methylaluminum sesquichloride, dimethylaluminum monochloride, ethylaluminum dichloride, ethylaluminum sesquichloride, diethylaluminum monochloride, isobutylaluminum dichloride,
Isobutylaluminium sesquichloride, diisobutylaluminum monochloride, and the like can be mentioned. Particularly preferred are ethylaluminum dichloride, ethylaluminum sesquichloride, and diethylaluminum monochloride, and among them, ethylaluminum sesquichloride gives the most preferable results. The organic aluminum halide compound treatment is performed by adding an organic aluminum halide compound to a homogeneous hydrocarbon solution, preferably in a process of 10-10.
The reaction can be carried out at a temperature of 0° C. and a hydrocarbon-insoluble solid catalyst can be obtained, so the solid can be separated and washed with a hydrocarbon solvent.

Therefore, the amount of each component to be used is determined by the amount of X' in the general formula of each component.
, X', OR'', ORI, M, 9 and T1 are selected in a molar ratio that satisfies the following formula, and within this range a highly active catalyst can be obtained.

/≦M, 9/Ti≦da Next, as the organoaluminum compound used as a cocatalyst in the method of the present invention, for example, the general formula h#t', xi-p
(In the formula, R'tdl*JLp, ary-Jl/ represents a cycloalkyl group, and X4 represents a \rogen atom,
p represents a number from 1 to 3. ) and contains non-compounds. Examples of R4,X' include those exemplified as R1,zt. Specific examples include trialkylaluminum such as triethylaluminum, tri-n-propylaluminum, and triisobutylaluminum, and diethylaluminum monochloride.

In the method of the present invention, the solid catalyst component described above is subjected to a polyethylene precipitation treatment in a hydrocarbon solvent in which polyethylene is dissolved, and the solid catalyst component (t per unit weight part of Al) is 0.
/-100 parts by weight polyethylene coating treatment.

Hydrocarbon solvents used in this treatment include aliphatic hydrocarbon solvents, specifically normal pentane, normal hexane, normal octane, etc. or mixtures thereof, alicyclic hydrogen solvents such as cyclopentane, cyclohexane, benzene, Examples include aromatic hydrogen ashing such as toluene and xylene.

In addition, the viscosity average molecular weight of the polyethylene used = -〇0
A relatively low molecular weight polyethylene of about 0 to a high molecular weight polyethylene of about 300,000 can be used. It may be a homopolymer of ethylene, or a copolymer of ethylene and a small amount of other α-olefin.

The conditions for the dissolution and reprecipitation treatment can be appropriately selected depending on the type of hydrocarbon solvent used, the molecular size of the polyethylene, etc., but the dissolution and reprecipitation of the polyethylene are usually carried out in the range of 1 gO<0>C to 20<0>C.

Polyethylene is dissolved by increasing the temperature of the system while stirring. By adding the solid catalyst component obtained above to this state and slowly cooling it, polyethylene precipitates and envelops the particles of the solid catalyst component. The cooling rate at this time can be appropriately selected depending on the type of hydrocarbon solvent and the type of polyethylene used, but it is usually O1-℃/M~1
It will be held at 0℃/Ryu.

The amount of polyethylene used is 0 per solid catalyst unit chamber lid.
．． /-100 parts by weight, preferably in the range of o,s to 100M violet parts.

Further, the concentration of the polymer in the dissolution and reprecipitation treatment steps is not particularly limited, but is usually carried out in the range of 1 wt % to 3θ wt %.

The catalytic polyethylene composition thus obtained can be used for polymerization without washing.

The thus prepared solid catalyst and polyethylene composition were used in a hydrocarbon solvent under slurry polymerization conditions, i.e., 41°C.
Homopolymerization of ethylene or copolymerization of ethylene and other α-olefins is carried out at a temperature of 0°C to lθ0°C.

Other α-olefins that are copolymerization components include α-olefins having 3 or more carbon atoms.

Examples Eva, propylene, l-butene, l-pentene, l-
Examples include hexene, l-octene, and /-thecene.

Moreover, these can also be mixed and copolymerized.

The hydrocarbon solvent used in this polymerization includes aliphatic hydrocarbon solvents, specifically propane, isobutane, normal butane, normal pentane, normal hexane, normal octane, etc., or mixtures thereof, cyclopentane, cyclohexane, etc. Examples include alicyclic hydrocarbon solvents, among which aliphatic hydrocarbons having two to five carbon atoms are preferred.

In this polymerization reaction, the ratio of solid catalyst (1) ethylene composition and organoaluminum compound used is usually kl/T.
The atomic ratio of i is preferably 0.0/ to 10θ, preferably Q, and more preferably 1 to 20. The main polymerization reaction is usually carried out at a temperature ranging from room temperature to 100°C, preferably from yo to 90°C, and at a polymerization pressure selected from a range from normal pressure to 100 atm.

Further, the molecular reservoir can be adjusted by a conventional method such as the presence of hydrogen in the polymerization reaction zone.

Compared to the prepolymerization treatment using olefin, which is a catalyst component for olefin polymerization, as in the present invention, the powder properties are better in the high density region, medium density region, and low density region, and the boI ethylene containing less solvent-soluble electropolymer is produced. can be manufactured.

Further, the present invention can be effectively used in any method such as gas phase polymerization or in which the polymer is produced in a solid state to produce female lingual cavities.

〔Example〕

Next, the present invention will be explained in detail with reference to examples.
A is not limited to the following examples unless it exceeds the gist thereof.

In addition, in the following examples, the melt index is A
8TM D I+23g, measured at 190° C./6kg load based on rfT, and expressed in M. Further, the product f of a solvent-soluble polymer (grease wax) was extracted with n-hexane at the boiling point for a period of time using a Soxhlet extractor.

Example-7 A) Preparation of catalyst component Magnesium ethoxide 1i311. , tri-n-butoxychlorotitanium 15θ & bn-butanol, 371 were mixed at 100° C. for 6 hours to homogenize. Then 60℃
Lower the temperature to n-hexane, 27! Added lj.

Then ethylaluminum sesquichloride (IIIA
17/l of SO) was added dropwise, and stirring was continued at 60°C for 1 hour.

By washing the resulting precipitate with n-hexane, a brown catalyst component 091 was obtained.

B) 500t of n-hexane in a glass pressure-resistant container with a polyethylene-coated processing capacity of 1t/J.
Polyethylene 37& having an al viscosity average molecular weight of 53,000 was charged, and the temperature was raised to 720'C while stirring.

In this state, the polyethylene was completely dissolved and became a homogeneous solution. To this, 3.7 g of the catalyst component obtained in the above (transformation)
After adding and continuing stirring for S minutes, do not continue stirring.
"The temperature decreased at a rate of C7 minutes.

Visual observation revealed that polyethylene began to precipitate when the system temperature reached around 100°C. This catalyst-polyethylene composition slurry was cooled to room temperature and used for polymerization without washing.

C) Into an autoclave with a polymerization content of ethylene - 1, add 10% normal hexane.
00rd, catalyst composition obtained in B) above CocoOIJg
<Solid catalyst equivalent -〇~) was charged. Also, diethyl aluminum monochloride 0. ◎ After raising the temperature inside the autoclave to 9o''C, a predetermined amount of H3 was introduced, and then ethylene and diethylaluminium monochloride (DFtAO) were supplied. Polymerization was started. Ethylene was intermittently supplied so that the total pressure was kept constant, and the polymerization reaction was continued for a period of S hours. After that, a small amount of ethanol was added to stop the polymerization, and unreacted ethylene was purged.

The bulk density of this polyethylene powder is
4Io, normal hexane extracted fleece wax is 2
．． He was in charge of 9wt.

Example Using the catalyst compositions obtained in Examples/A and B).

Polymerization of ethylene was carried out in the same manner as in Example IC) except that the composition of the polymerization reaction gas phase was changed.

The results are shown in Table 1.

Example 3 Triethylaluminum (TEA) cocatalyst 0,/l
Polymerization of ethylene was carried out in exactly the same manner as in Example/a), except that the catalyst charging cap was changed to 10IIQ) and the gas phase H1 composition was adjusted.

The results are shown in Table 1.

Example: 100% normal hexane in an autoclave with an internal capacity of 21%.
011L! In the same manner as in Example/c), the catalyst composition Coco O~ (solid catalyst conversion Ko θ) obtained in Example/B) and 0.3-m DIIol of diethylaluminum monochloride were charged, and the internal temperature was set to 0. “The temperature rose to c.Here 2
01 butene and Hl ethylene are supplied to start polymerization, and the total pressure is 1-kl? The polymerization reaction was continued for 5 hours while ethylene was intermittently supplied so that /ff1-G.

The results are shown in Table 1. It is also clear that the bulk density is higher than that of Comparative Example 3, and the content soluble in boiling normal hexane is also significantly reduced.

Comparative example 1. Example / o The solid catalyst component obtained in A) was directly coated with polyethylene without being coated with polyethylene.
), and butene copolymerization was carried out in the same manner as in Example D. The results are shown in Table 1.

Compared to Examples, the bulk density is lower and the content soluble in boiling normal hexane is significantly higher.

Example S Purified normal hexane 2004. Add 7 days of polyethylene with a viscosity average molecular weight of tj+J, and reduce the temperature to /-0°C while stirring.
It rose to Here, a solid catalyst obtained in the same manner as Example/A)? After adding 4IOIr and continuing stirring for 70 minutes, the temperature was lowered at a rate of 0.7 minutes without continuing stirring.

Next, using the catalyst composition obtained above, jtoolJ
Continuous polymerization of ethylene-norbutene copolymerization is carried out using a normal hexane solvent in a joll at liquid level in a jacketed polymerization tank.

The above catalyst composition was added to the polymerization tank at a rate of [Eg/Hr, diethylaluminum chloride-, 3
ji/Hr, fgp normal hexane 7SψHr, /
-butene j 1r14r % hydrogen! Polymerization fM degree gθ℃, total pressure Skg/-
・Continuous polymerization was carried out for 10 days with an average residence time of 1 hour in G1.

Average polymerization activity during this period
I-tactile Hr-Pθry), the MI of the obtained polymer is l,s (1/'0 min), the density #'i0.9
410 i9 /cI! .

Boiling normal hexane extract u s '-A vtt%
Met.

Heat removal by jacket water flow is extremely stable, and the overall heat transfer coefficient (Ull) of the heat transfer surface immediately after the start of polymerization, ? ri0
For [kcal/77 (・hr・deg]), the overall heat transfer coefficient (Us) just before the end of polymerization is U J 4! / [kc
a] 7771'・hr-deg], the average rate of decline during that time (/-Ul/Ull) Fi o, 3rd grade/
It was DAY.

When one reactor was opened and inspected after the completion of operation, no adhesion was observed on the vessel wall.

Based on these results, it was determined that continuous operation for an even longer period of time is possible.

Comparative Example 3 Using the solid catalyst obtained in the same manner as in Example/A), continuous ethylene-7-butene copolymerization was carried out in the same manner as in Example S.

The obtained polymer had an MI of /, 3 (11/10 min), a density of 0.9 da/l/cp/l, and a m-normal hexane extraction fractionation.7. It was excellent. However, the overall heat transfer coefficient of the polymerization tank decreased significantly, and the overall heat transfer coefficient was dlθ (kcal/go・hr−40g) immediately after the start of polymerization, but after 5 days it was 300 (koILVgo・hr−40g).・do
g), and the polymerization was finally stopped. Average rate of decline during this period (/-UM/U6) II'it, 4/
%/DAT.

After driving. When the vessel was opened and inspected, thick wax-like deposits were found on the entire wall of the vessel.

〔Effect of the invention〕

According to the method of the present invention, it is possible to produce polyethylenes ranging from high-density polyethylenes to medium- and low-density polyethylenes, which have good powder properties and contain less solvent-soluble polymers.

Applicant: Mitsubishi Chemical Industries, Ltd. Amendment 1: 2 Title of the invention: Process for producing polyolefin (596)
"Detailed description of the invention" column of Mitsubishi Chemical Industries, Ltd. specification

Claims (2)

[Claims] (1) Homopolymerization of ethylene or copolymerization of ethylene with other α-olefins using a catalyst system consisting of a solid catalyst component containing (al magnesium, titanium, and) In this case, the solid catalyst component (al) is prepared by precipitating polyethylene on the solid catalyst component (at) in a hydrocarbon solvent to give an amount of 0.1 to 300% per unit weight part of the solid catalyst component (al).
1. A method for producing polyolefin, comprising using a polyolefin treated with a weight part of polyethylene. (2) The above-mentioned solid catalyst component (al is a reaction product of an oxygen-containing organic compound of magnesium and a titanium halogen compound, or a reaction product of an oxygen-containing organic compound of magnesium, an oxygen-containing organic compound of titanium, and an A/minium halogen compound) The manufacturing method according to claim 7, which is a product.