JPH078891B2 - Olefin continuous polymerization - Google Patents

Description

TECHNICAL FIELD The present invention relates to a continuous polymerization method of olefin. More specifically, it relates to a method for producing a polyolefin having excellent melt tension and melt elasticity and excellent melt moldability by an industrially advantageous operation.

[Conventional technology]

There are already many known methods for polymerizing ethylene using a catalyst formed of a highly active titanium catalyst component (A ') containing magnesium, titanium and halogen as essential components and an organoaluminum compound catalyst component (B'). I have a suggestion. There are also many proposals for a method of employing multi-step polymerization of two or more steps in homopolymerization and copolymerization of olefin such as ethylene.

In general, polyolefins such as polyethylene and polypropylene are lightweight, excellent in economical efficiency and excellent in melt moldability, and therefore are used for general purpose in the fields of melt molding such as extrusion molding, blow molding and injection molding. However, although these polyolefins, especially ethylene-based polymers containing an ethylene component as a main component, especially ethylene-based polymers polymerized by a Ziegler-type polymerization catalyst are excellent in melt moldability, especially in the field of blow molding. Is poor in melt tension and melt elasticity, and as a result, the phenomenon of drawdown is likely to occur during molding, and weld lines are likely to occur in a molded product, and improvement thereof is strongly demanded. Therefore, various attempts have been proposed to improve the physical properties of polyolefin such as ethylene polymer. For example, a method for achieving the object by improving the catalyst and its composition or polymerization formulation during the production of polyolefin, a method for achieving the same object by incorporating a modifier into the polyolefin, or the polyolefin. Attempts have been made to achieve the same purpose by partially cross-linking, but there are drawbacks such as complicated formulation and insufficient effect in any formulation, and further, melt tension and melt elasticity There is a need for excellent polyolefin.

For example, JP-B-48-42716 discloses that ethylene is polymerized in the presence of a specific catalyst in an atmosphere of 5 to 95% by volume of hydrogen in the first stage and in the second stage of 0 to 2% by volume. A method of polymerizing under an atmosphere of hydrogen to produce a bimodal polymer having a broad molecular weight distribution is disclosed. It is also disclosed that the polymer has excellent flow characteristics and resistance to environmental stress strain.

JP-B-46-11,349 discloses that ethylene or ethylene and 1
A mixture with up to 0% by weight of α-olefin having 3 to 15 carbon atoms is polymerized in two steps at a temperature of 50 to 120 ° C., with the amount of the organoaluminum compound of the titanium trichloride compound and of the organoaluminum compound The type is specified and the polymerization in one stage is carried out in an atmosphere of 0 to 10% by volume of hydrogen in an amount of 5 to 30% by weight of the total polymer and the polymerization in the other stage is performed in a range of
A method for producing a broad molecular weight distribution polyolefin by carrying out total polymerization at 70 to 95% by weight under an atmosphere of 80% by volume of hydrogen is disclosed. It is also disclosed that the polyolefin has high tear strength and good surface properties.

Also, Japanese Patent Publication No. 59-10724 and corresponding US Patent No. 4,33.
No. 6,352 discloses a multi-stage continuous polymerization method for producing polyethylene having different molecular weights in three or more polymerization vessels connected in series. In this method, the polyethylene with the highest molecular weight has a viscosity average molecular weight of 10
The viscosity average molecular weight of the polyethylene having a lower molecular weight is 1,000 to 50,000, and the production rate is 1 to 10% of the overall polymer production rate. It is specified that the viscosity average molecular weight of the higher molecular weight polyethylene is 2 to 100 times that of the higher molecular weight polyethylene, and that the production ratio of the former to the latter is 3: 7 to 7: 3. In Example 1 disclosed in the publication, a polymerization apparatus consisting of three polymerization vessels connected in series was used, and an ultrahigh molecular weight polyethylene having a molecular weight of about 3,000,000 was produced in the first polymerization vessel on the upstream side. In the second polymerization vessel, relatively low molecular weight polyethylene was produced, and in the third polymerization vessel, relatively high molecular weight polyethylene was produced.
A polymer with a value of 0.3 is obtained.

[Problems to be solved by the invention]

An object of the present invention is to provide a novel multi-stage continuous polymerization method for olefin.

Another object of the present invention is to provide a multi-stage continuous polymerization method of olefin, which can avoid the production of a large amount of transition products even when the brand is changed.

Yet another object of the present invention is, when compared to conventional polyolefins in which the ultra high molecular weight polyolefins are well dispersed and therefore have the same ultra high molecular weight polyolefin content.
An object of the present invention is to provide an industrially advantageous multi-stage continuous polymerization method of olefin, which is capable of producing a polyolefin having excellent melt tension and melt elasticity.

Still another object of the present invention is to provide a multi-stage continuous polymerization method of olefin which is suitable not only for producing homopolyolefin but also for producing copolyolefin.

Still another object of the present invention is to provide an industrially advantageous multi-stage stack of olefins which can use different kinds of suitable polymerization catalysts for each polymerization vessel or at least each polymerization series for producing polyolefins having different polymerization degrees. To provide legality.

Still another object of the present invention is to provide a multi-stage continuous polymerization method of olefin which can give polyolefin which is excellent in melt tension, die swell, drawdown or stress cracking property.

Further objects and advantages of the present invention will be apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are
Polymerization of olefin as a raw material in the presence of (A) a solid titanium catalyst component containing titanium, magnesium and halogen as essential components, and (B) a catalyst formed from an organoaluminum compound, comprising at least four polymerization vessels. Polymerization is carried out in a multi-stage continuous polymerization process using an apparatus, with at least 3
In a continuous polymerization method of olefins in which polyolefins having different intrinsic viscosities [η] (values measured at 135 ° C. in decalin solvent) are produced in a base polymerization vessel, (i) are connected in series as a polymerization device. At least 2
A first polymerization series consisting of a group of polymerizers and a second polymerization series consisting of at least two groups of polymerization vessels connected in series, the first polymerization series and the second polymerization series being the second polymerization series. Using a multi-stage polymerization apparatus in which the most downstream side is connected to the line after the first polymerization vessel on the upstream side of the first polymerization series or to the polymerization vessel, and (ii) at least the second polymerization series is used. The raw material olefin, which is polymerized in the entire polymerization series in one polymerization vessel, is 0.1 to
The intrinsic viscosity [η] _U (value measured at 135 ° C. in decalin solvent) corresponding to 5 wt% and by polymerizing 0.2 to 50 wt% of the raw material olefin which is polymerized in the second polymerization series is 15 dl / An intrinsic viscosity [η] is obtained by polymerizing the residual raw material olefin polymerized in the second polymerization series in the presence of hydrogen in the residual polymerization vessel of the second polymerization series in the presence of hydrogen in the residual polymerization vessel of the second polymerization series. ] (Value measured at 135 ° C. in decalin solvent) produces a polyolefin having a smaller value than [η] _U , thus polymerizing 5 to 70% by weight of the raw material olefin which is polymerized in the entire polymerization step in the second polymerization series. And (iii) the intrinsic viscosity [η] is obtained by polymerizing the raw material olefin in each of the first polymerization series polymerization vessels.
(A value measured at 135 ° C. in a decalin solvent) which is different from each other and produces a polyolefin smaller than [η] _U, which is achieved by a continuous polymerization method of olefin.

In carrying out the polymerization method of the present invention, various transition metal-containing catalysts such as those conventionally proposed in the medium / low pressure method can be used. As such a catalyst, for example, a transition metal-containing catalyst formed from a transition metal compound catalyst component and an organometallic compound catalyst component of a metal of Groups 1 to 3 of the periodic table can be used.

The transition metal compound catalyst component is titanium, vanadium,
The compound of a transition metal such as chromium or zirconium may be liquid or solid under the conditions of use. These do not have to be single compounds,
It may be supported on or mixed with other compounds. Further, it may be a complex compound or a complex compound with another compound. The above-mentioned preferred component is a highly active transition metal compound catalyst component capable of producing 5,000 g or more, particularly 8,000 g or more, of olefin polymer per millimole of transition metal, and a typical example thereof is a magnesium compound. A highly activated titanium catalyst component can be exemplified. For example, a solid titanium catalyst component containing titanium, magnesium and halogen as essential components,
Amorphous magnesium halide is included, and its specific surface area is preferably about 40 m ² / g or more, particularly preferably about 80 m ² / g. And, it may contain an electron donor such as an organic acid ester, a silicic acid ester, an acid halide, an acid anhydride, a ketone, an acid amide, a tertiary amine, a phosphoric acid ester, a phosphorous acid ester, an ether and the like. The titanium catalyst component contains, for example, about 0.5 to about 10% by weight of titanium, particularly about 1 to about 8% by weight, and the titanium / magnesium (atomic ratio) is about 1/2 to about 1/100, especially about 1%. / 3 to about 1/50, halogen / titanium (atomic ratio) about 4 to about 100, especially about 6 to about 80, electron donor / titanium (molar ratio) 0 to about 10,
Particularly, those in the range of 0 to about 6 are preferable.

Alternatively, as such a titanium catalyst component, a titanium catalyst component in which a magnesium compound dissolved in a hydrocarbon solvent in the presence of an electron donor such as alcohol and a liquid titanium compound are used in combination can be exemplified. .

The organometallic compound catalyst component is an organometallic compound having a bond between a metal of Group 1 to Group 3 of the periodic table and carbon,
Examples thereof include organic compounds of alkali metals, organic metal compounds of alkaline earth metals, and organic aluminum compounds. For example, alkyl lithium, aryl sodium, alkyl magnesium, aryl magnesium, alkyl magnesium halide, aryl magnesium halide, alkyl magnesium hydride, trialkyl aluminum, alkyl aluminum halide, alkyl aluminum hydride, alkyl aluminum alkoxide, alkyl lithium aluminum, and mixtures thereof. Can be illustrated.

In addition to the above two components, hydrogen, halogenated hydrocarbons, electron donor catalyst components such as organic acid esters, silicic acid esters, carboxylic acid halides, and carboxylic acid amides are used for the purpose of controlling stereoregularity, molecular weight, molecular weight distribution, etc. , Tertiary amines, acid anhydrides, ethers, ketones, aldehydes and the like may be used. This electron donor component may be used in a form in which a complex compound (or addition compound) is previously formed with a catalyst component of an organometallic compound during polymerization, and other compounds such as Lewis acid such as aluminum trihalide can be used. You may use it in the form which formed the complex compound (or addition compound) with. The catalyst may be supplied only to the one-stage polymerization reactor or may be supplied in parallel to the one-stage polymerization reactor and each of the other polymerization reactors.

In the method of the present invention, a polymerization apparatus comprising at least four polymerization vessels is used for the olefin polymerization reaction. The polymerization system comprises a first polymerization series and a second polymerization series. Each of the first polymerization series and the second polymerization series is composed of at least two polymerization vessels connected in series. The first polymerization series and the second polymerization series are in communication with each other by connecting the line after the first polymerization vessel upstream of the first polymerization series or the polymerization vessel with the second polymerization series. .

Some examples of the embodiment of the polymerization apparatus used in the present invention are as follows.

A polymerization apparatus in which the first polymerization series comprises two polymerization vessels, and a second polymerization series consisting of two polymerization vessels connected in series is connected to a line connecting these polymerization vessels. This first
In the above embodiment, when a relatively high molecular weight polyolefin is produced in the upstream polymerization vessel of the first polymerization series and a relatively low molecular weight polyolefin is produced in the downstream polymerization vessel, and vice versa. In some cases, a relatively low molecular weight polyolefin is produced in the upstream polymerization vessel and a relatively high molecular weight polyolefin is produced in the downstream polymerization vessel. In the former case, the hydrogen pressure in the downstream polymerization vessel can be made lower than the hydrogen pressure adopted for producing relatively high molecular weight polyolefin in the upstream polymerization vessel, so that the polymerization process transition At the same time, the hydrogen pressure should be released and lowered. Therefore, the former case is preferably used when producing homopolyolefin. In the latter case, it is known that it is preferable to add a comonomer used for reducing stress cracking property (ESCR) to a polymerization vessel which produces a polyolefin having a relatively high molecular weight. It is advantageous in that it can be added to the downstream polymerization vessel. This is because when a comonomer is added to produce a relatively high molecular weight polymer in the upstream polymerization vessel, unreacted comonomer is substantially completely polymerized when the process moves to a polymerization step to produce a relatively low molecular weight polyolefin. This is because it has to be removed before carrying out the reaction, and its operation is extremely difficult or practically impossible.

In this first embodiment, ultra high molecular weight polyolefin is produced in one of the second polymerization series, preferably in the upstream polymerization vessel and in the other polymerization apparatus, preferably in the downstream polymerization vessel, other than ultra high molecular weight polyolefin. Polyolefin is produced.

In the polymerization apparatus of the second aspect, the second polymerization series is connected to the middle or last polymerization vessel of the first polymerization series.

In this case as well, the same as described above in the first aspect can be said.

In the polymerization apparatus of the third aspect, the second polymerization series is connected to the line from the last polymerization vessel of the first polymerization series.

In the third aspect, the polymerization is not carried out in the presence of the polyolefin produced in the polymerization vessel of the other polymerization series in any of the polymerization vessels of the first polymerization series and the second polymerization series. Since the mixing with the polyolefin produced in the polymerization vessel of another polymerization series is not carried out, the third embodiment is that the polymers produced in the first polymerization series and the second polymerization series are mixed. It is industrially extremely advantageous as a polymerization device to be combined.

In the second polymerization series of the method of the present invention, the raw material olefin which is polymerized in the entire polymerization series is prepared in at least one polymerization vessel.
The intrinsic viscosity [η] _U (value measured at 135 ° C. in decalin solvent) was obtained by polymerizing 0.2 to 50% by weight of the raw material olefin which is equivalent to 0.1 to 5% by weight and is polymerized in the second polymerization series. It is necessary to produce ultra high molecular weight polyolefins above 15 dl / g. Preferably, it corresponds to 0.5 to 4% by weight of the olefin polymerized in the entire polymerization step and 1 to 50% by weight of the raw olefin polymerized in the second polymerization series.
Is polymerized, more preferably 1 to 3% by weight of the olefin that is polymerized in the entire polymerization step and 2 to 50% by weight of the raw material olefin that is polymerized in the second polymerization series. The intrinsic viscosity of ultrahigh molecular weight polyolefin is preferably 20 to 50 dl / g, more preferably 25 to 50 dl / g.
Is. In the polymerization step, when the ultrahigh molecular weight polyolefin produced has an intrinsic viscosity [η] _U of less than 15 dl / g,
The effect of improving the melt tension and melt elasticity of the polyolefin will not be obtained, and even if the proportion of olefin that is polymerized in the polymerization step is less than 0.1% by weight, it will not be possible to obtain a polyolefin having excellent melt tension and melt elasticity as well. Further, if it exceeds 10% by weight, the formation of fisheyes, spots and the like will increase in the molded product, so it is necessary to be within the above range.

Further, in the second polymerization series, the intrinsic viscosity [η] is obtained by polymerizing the residual raw material olefin which is polymerized in the second polymerization series in the presence of hydrogen in the residual polymerization vessel of the second polymerization series. Polyolefin smaller than _U is produced, thus polymerizing 5 to 70% by weight of the raw olefin which is polymerized in the entire polymerization step in the second polymerization series. In the remaining polymerization vessel of the second polymerization series, preferably 10 to 50% by weight of the raw material olefin which is polymerized in the entire polymerization step is polymerized.

In the method of the present invention, in the polymerization step for producing ultrahigh molecular weight polyolefin, the polymerization is carried out in the presence of a catalyst composed of the transition metal compound catalyst component (A) and the organometallic compound catalyst component (B). The polymerization can be carried out by a gas phase polymerization method or a liquid phase polymerization method. In any case, in the polymerization step for producing ultra-high molecular weight polyolefin, the polymerization reaction is carried out in the presence of an inert medium, if necessary, and, for example, in the gas phase polymerization method, a dilution containing an inert medium is carried out as necessary. It is carried out in the presence of an agent, and in the liquid phase polymerization method, if necessary, it is carried out in the presence of a solvent consisting of an inert medium.

In the polymerization step for forming the ultrahigh molecular weight polyolefin, the transition metal compound catalyst component (A) is used as a catalyst, for example, about 0.01 to about 200 mmol, and particularly about
0.05 to about 100 millimoles of the organometallic compound catalyst component (B), the amount of metal in the component (B) / transition metal (atomic ratio) in the component (A) is about 0.01 to about 1000, particularly about 0.1 to about 500. It is recommended to use it in such a ratio that The temperature of the polymerization step for forming the ultra high molecular weight polyolefin is usually in the range of about -20 to about 200 ° C, preferably about 0 to 150 ° C, particularly preferably about 5 to about 120 ° C. Further, the pressure during the polymerization reaction is a pressure range that can be liquid phase polymerization or gas phase polymerization at the temperature, for example from atmospheric pressure to about 100 kg / c
m ² , preferably from atmospheric pressure to about 50 kg / cm ² .
The polymerization time in the polymerization step may be set so that the amount of prepolymerized polyolefin is about 0.5 g or more, preferably about 1 g or more per 1 gram atom of the transition metal in the transition metal catalyst component. Further, in the polymerization step, in order to produce the ultrahigh molecular weight polyolefin, it is preferable to carry out the polymerization reaction in the absence of hydrogen. Furthermore, after carrying out the polymerization reaction, the polymer may be isolated and stored once in an inert medium atmosphere.

Examples of the inert medium which can be used in the polymerization step for producing the ultra high molecular weight polyolefin include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane and kerosene; cyclopentane, cyclohexane, etc. Alicyclic hydrocarbons; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as dichloroethane, methylene chloride and chlorobenzene; and mixtures thereof. Of these, the use of aliphatic hydrocarbons is particularly desirable.

In the method of the present invention, the remaining olefin polymerization reaction is carried out in the presence of hydrogen in the first polymerization step other than the second polymerization step for producing the ultrahigh molecular weight polyolefin.

That is, in each polymerization vessel of the first polymerization series, by polymerizing the raw material olefin, the polyolefins having the intrinsic viscosities [η] different from each other and smaller than the above [η] _U are produced.

In the polymerization in the first polymerization series, raw material olefin and hydrogen are supplied to the upstream first polymerization vessel, and further a catalyst comprising the transition metal compound catalyst component (A) and the organometallic compound catalyst component (B) is supplied. Will be implemented. When the polymerization is a polymerization step after the second polymerization vessel, the catalyst contained in the polymerization product liquid generated in the previous step can be used as it is. Further, if necessary, the transition metal compound catalyst component (A) and / or the organometallic compound catalyst component (B) may be additionally supplemented. The ratio of the raw olefins polymerized in the first polymerization step (series) is 95 to 9 with respect to the total olefin components polymerized in the entire polymerization step.
It is 9.9% by weight, preferably 96-99.5% by weight.

The hydrogen supply ratio in each polymerization step carried out in each polymerization vessel in the first polymerization series is usually 1 to 99 mol, preferably 5 to 95 mol, relative to 100 mol of olefin supplied to each polymerization process. It is in the molar range.

The concentration of each catalyst component in the polymerization product liquid in the polymerization vessel in each polymerization step in the first polymerization series is about 0.00 when the treated catalyst is converted to transition metal atoms per 1 polymerization volume.
1 to about 0.1 mmol, preferably about 0.005 to about 0.1
And the polymerization system organometallic compound catalyst component (B)
It is preferred that the transition metal (atomic ratio) in the metal / transition metal compound catalyst component (A) is adjusted to about 1 to about 1000, preferably about 2 to about 500. Therefore, the organometallic compound catalyst component (B) can be additionally used if necessary. In the polymerization system, hydrogen, an electron donor, a halogenated hydrocarbon and the like may coexist for the purpose of controlling the molecular weight and the molecular weight distribution.

The polymerization temperature is within a temperature range in which slurry polymerization, solution polymerization or gas phase polymerization is possible, and is preferably about 50 ° C. or higher, more preferably about 60 to about 200 ° C. Further, the polymerization pressure is recommended to be, for example, atmospheric pressure to about 200 kg / cm ² , and particularly atmospheric pressure to about 100 kg / cm ² . It is preferable to set the polymerization time such that the amount of the polymer produced is about 5000 g or more, and particularly about 10000 g or more per 1 mmol of transition metal in the transition metal compound catalyst component.

Similar to the step of polymerizing the ultrahigh molecular weight polyolefin, this step can be carried out by a gas phase polymerization method or a liquid phase polymerization method. Of course, it is also possible to employ different polymerization methods in each polymerization step. Among the liquid phase polymerization methods, the suspension polymerization method can be adopted, and the solution polymerization method can also be adopted. In any case, in the polymerization step, the polymerization reaction is usually carried out in the presence of an inert medium. For example, the gas phase polymerization method is carried out in the presence of an inert medium diluent, and the liquid phase polymerization method is carried out in the presence of an inert medium solvent. As the inert medium, the inert medium exemplified in the polymerization step for forming the ultra high molecular weight polyolefin can be similarly exemplified.

In the polymerization step in the first series other than the ultrahigh molecular weight polyolefin polymerization step, the intrinsic viscosity [η] is smaller than the intrinsic viscosity [η] _{U of the} ultrahigh molecular weight polyolefin as described above, and each step in the two polymerization vessels is performed. Produces a polyolefin with at least different intrinsic viscosities.

For example, the intrinsic viscosity of ultra high molecular weight polyolefin is [η] _U
And the intrinsic viscosity of the lowest intrinsic viscosity polyolefin produced in the first polymerization series is represented by [η] _L ,
The ratio of [η] _L / [η] _U is preferably 0.005 to 0.07, more preferably 0.01 to 0.05. Also, [η] _L
When the intrinsic viscosity of the polyolefin produced in the first polymerization series having an intrinsic viscosity lying between and [η] _U is represented by [η] _H , the ratio of [η] _H / [η] _U is preferably 0.02-0.
2, the ratio of [η] _L / [η] _H is 0.02 to 0.8, more preferably the ratio of [η] _H / [η] _U is 0.05 to 0.2, and [η] _L / [η] ] The ratio of _H is 0.05-0.5.

In the method of the present invention, [η] of the polyolefin obtained in the final polymerization step is usually 0.1 to 4.5 dl / g, preferably 0.5 to 4.0 dl / g, particularly preferably 0.7 to
The polymerization reaction is carried out until reaching 4.0 dl / g.

The polyolefin obtained by the method of the present invention is excellent in melt tension and melt elasticity as compared with the polyolefin produced by the conventional method, and is excellent in melt moldability.

The method of the present invention can be carried out batchwise, semi-continuously or continuously.

Preferred olefins to which the method for polymerizing olefins of the present invention is applicable are α-olefins having 2 to 20 carbon atoms.

Such olefins include, for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene,
Examples of α-olefins include 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3-methyl-1-pentene. The method of the present invention can be applied to a method for producing a homopolymer of these α-olefins or a method for producing a copolymer composed of two or more kinds of mixed components.
Among these α-olefins, it is particularly preferable to apply the method of the present invention to a process for producing ethylene or a copolymer of ethylene and another α-olefin, the ethylene-based polymer having an ethylene component as a main component. preferable.

〔Example〕

Next, the present invention will be specifically described with reference to examples. In addition,
Melt tension (melt tension) and expansion ratio (die swell ratio) in Examples and Comparative Examples were measured by the following methods.

Melt tension: The stress when the melted polymer was stretched at a constant speed was measured. That is, using a melt-tension measuring machine manufactured by Tokyo Seiki Seisakusho, resin temperature 190 ° C, extrusion speed 10 mm / mi
n, winding speed 6.28 m / min, nozzle diameter 2.09 mmφ, nozzle length 8 mm. The polymer was pre-blended with a crosslinking stabilizer, 0.1 wt% of 2,6-di-t-butyl-para-cresol.

Expansion ratio (die swell ratio): Using the same equipment as the melt tension, resin temperature 190 ℃, 10mm /
The expansion coefficient (%) in the radial direction with respect to the nozzle diameter of the diameter of the parison extruded to 10 cm at a constant extrusion speed was measured. Also in this case, a crosslinking stabilizer was blended in the same manner as in the measurement of melt tension.

Examples 1-8, Comparative Examples 1-2 <Preparation of Ti catalyst component> Anhydrous magnesium chloride 47.6 kg, n-decane 250, and 2-ethyl-hexanol 183 were heat-treated at 130 ° C for 2 hours to form a uniform solution. Afterwards, ethyl benzoate 11.4 is added.

This homogeneous solution is added dropwise to 2000 parts of titanium tetrachloride cooled to -20 ° C with stirring for 20 minutes. After gradually raising the temperature, ethyl benzoate 24.3 was added at 80 ° C, and the mixture was further stirred at 80 ° C for 2 hours. The solid portion was collected by filtration, resuspended in 1000 parts of titanium tetrachloride, and heated at 90 ° C. for 2 hours.
Then, the solid substance was collected by filtration, and thoroughly washed with purified hexane until no free titanium compound was detected in the washing liquid. The titanium catalyst component contained 4.0% by weight of titanium, 20.0% by weight of magnesium, 59.0% by weight of chlorine and 15.2% by weight of ethyl benzoate and had a specific surface area of 225 m ² / g.

<Polymerization> Polymerizer A with a diameter of 15 cm and a volume of 30 shown in FIG. 1, and a diameter
A multi-stage polymerization apparatus comprising 50 cm and a volume of 200 polymerization vessels B, C and D and a hydrogen flash drum E having a diameter of 50 cm and a volume of 100 was used.

In the polymerization vessel A, 1.0m of titanium catalyst made into hexane slurry
Mol / HR, hexane solution of triethylaluminum in a ratio shown in Table 1, and hexane in a total of 30 / HR and ethylene in a polymer production ratio shown in Table 1 were continuously introduced to carry out polymerization. Natsuta. The polymerization temperature was adjusted to the target temperature with a jacket. The pressure in the polymerization vessel was adjusted to 5-6 kg / cm ² G by adding N ₂ . Polymerizer A
The slurry containing the polymer produced in 1. was continuously discharged to the polymerization vessel B.

Polymerization was carried out by continuously introducing ethylene at 10 kg / HR into the polymerization vessel B. The density of the polymer was adjusted by continuously adding 1-butene or 4-methyl-1-pentene.
The molecular weight was adjusted by continuously adding H ₂ . The polymerization temperature was adjusted to 80 ° C with a jacket.
At this time, the pressure was in the range of 4 to 6 kg / cm ² G. Polymerizer B
Then, the slurry containing the produced polymer was continuously discharged and mixed with the slurry discharged from the polymerization vessel D.

Titanium catalyst in hexane slurry was added to Polymerizer C at 2.5mMo.
l / HR and hexane solution of triethylaluminum
100 mMol / HR and hexane total 60 / HR, ethylene 2
At 0.4 kg / HR, it was continuously introduced and polymerized. Hydrogen was added continuously to control the molecular weight. The polymerization temperature was adjusted to 80 ° C with a jacket. At this time, the pressure is 3 to 7 kg / cm ²
It was in the G range. The slurry containing the polymer produced in the polymerizer C was continuously discharged to the hydrogen flash drum E.

Hydrogen flash drum E has a temperature of 60 ° C and a pressure of 0.5 kg / cm ²
Adjusted to G. The slurry was continuously discharged from the hydrogen flash drum E, and continuously fed to the polymerization vessel D by the pump F.

Hexane 30 / HR, ethylene 10.4 kg / HR in Polymerizer D
Then, it was continuously introduced to carry out polymerization. 1-butene or 4-
The density of the polymer was adjusted by the continuous addition of methyl-1-pentene. Also, the molecular weight was adjusted by continuously adding hydrogen. The polymerization temperature was adjusted to 80 ° C with a jacket.

The slurry discharged from the polymerization vessel D was mixed with the slurry discharged from the polymerization vessel B, and then separated into a polymer and hexane by a centrifuge, and the polymer was dried and pelletized by an extruder. The results are shown in Table 1.

Comparative Example 3 <Catalyst preparation> The same procedure as in Example 1 was carried out.

<Polymerization> Polymerizer A with a diameter of 15 cm and a volume of 30 shown in FIG. 2 and a diameter
Polymerization vessels B and C with a volume of 50 cm and a volume of 200 and a diameter of 50 cm and a volume of 100
A multi-stage polymerization apparatus consisting of the hydrogen flash drum D.

Titanium catalyst in hexane slurry was added to polymerization vessel A. 4.
Polymerization was carried out by continuously introducing 0 mMol / HR, 20 mMol / HR of triethylaluminum as a hexane solution, 30 / HR of hexane in total and 1.2 kg / H of ethylene. The polymerization temperature was adjusted to the target temperature with a jacket. The slurry containing the polymer produced in the polymerization vessel A was continuously transferred to the polymerization vessel B by the pump F.

Into the polymerization vessel B, triethylaluminum as a hexane solution was continuously introduced at 100 mMol / HR, hexane at a total of 50 / HR and ethylene at 28 kg / HR, and polymerization was carried out.
Hydrogen was added continuously to control the molecular weight. The polymerization temperature was adjusted to 80 ° C with a jacket. At this time, the pressure was about 8.5 kg / cm ² G. The slurry containing the polymer produced in the polymerizer B was continuously discharged to the hydrogen flash drum D.

Hydrogen flush drum D has a temperature of 60 ° C and a pressure of 0.5 kg / cm ² G
And hydrogen was excluded from the vent. The slurry was continuously discharged from the hydrogen flash drum D and continuously introduced into the polymerization vessel C by the pump F.

Into the polymerization vessel C, ethylene was continuously introduced at 28 kg / H to carry out polymerization. At the same time, 1-butene was added continuously to control the density of the polymer. At the same time, hydrogen was continuously added to control the molecular weight. The polymerization temperature was adjusted to 80 ° C with a jacket.

The slurry discharged from the polymerizer C was separated into a polymer and a hexane solvent by a centrifuge, and the polymer was dried and pelletized by an extruder. The results are shown in Table 1.

[Brief description of drawings]

1 and 2 each show a schematic view of a polymerization apparatus used in Examples and Comparative Examples. A, B, C and D represent a polymerizer, E represents a hydrogen flash drum,
F indicates a pump.

Claims (1)

[Claims] 1. In the presence of (A) a solid titanium catalyst component containing titanium, magnesium and halogen as essential components, and (B) a catalyst formed from an organoaluminum compound,
The raw material olefin is polymerized by a multi-stage continuous polymerization process using a polymerization apparatus composed of at least four polymerization vessels, in which at least three different intrinsic viscosity [η] (in decalin solvent) (Value measured at 135 ° C. at 135 ° C.) in a continuous polymerization method of olefin, which comprises (i) at least 2 units connected in series as a polymerization device.
A first polymerization series consisting of a group of polymerizers and a second polymerization series consisting of at least two groups of polymerization vessels connected in series, the first polymerization series and the second polymerization series being the second polymerization series. Using a multi-stage polymerization apparatus in which the most downstream side is connected to the line after the first polymerization vessel on the upstream side of the first polymerization series or to the polymerization vessel, and (ii) at least the second polymerization series is used. The raw material olefin, which is polymerized in the entire polymerization series in one polymerization vessel, is 0.1 to
The intrinsic viscosity [η] _U (value measured at 135 ° C. in decalin solvent) corresponding to 5 wt% and by polymerizing 0.2 to 50 wt% of the raw material olefin which is polymerized in the second polymerization series is 15 dl / An intrinsic viscosity [η] is obtained by polymerizing the residual raw material olefin polymerized in the second polymerization series in the presence of hydrogen in the residual polymerization vessel of the second polymerization series in the presence of hydrogen in the residual polymerization vessel of the second polymerization series. ] (Value measured at 135 ° C. in decalin solvent) produces a polyolefin having a smaller value than [η] _U , thus polymerizing 5 to 70% by weight of the raw material olefin which is polymerized in the entire polymerization step in the second polymerization series. And (iii) the intrinsic viscosity [η] is obtained by polymerizing the raw material olefin in each of the first polymerization series polymerization vessels.
A method for continuous polymerization of olefins, wherein the polyolefins (values measured at 135 ° C. in a decalin solvent) are different from each other and are smaller than [η] _U.