JPH0159284B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a method for polymerizing highly stereoregular polyα-olefin using a so-called supported titanium catalyst. α-olefins such as propylene and butene are polymerized using a so-called carrier-type titanium catalyst consisting of a so-called carrier-type titanium composition in which titanium is supported on a carrier such as magnesium chloride and an organoaluminum compound, resulting in highly stereoregular properties. Methods for obtaining polyα-olefins are known. However, it is well known in the field that in conventional so-called supported titanium catalysts, the polymerization activity of the catalyst and the stereoregularity of the resulting polymer are inversely correlated, and it is difficult to maintain both at a high level. There is.
Even more unfavorably, supported titanium catalysts which yield polymers with higher stereoregularity have the drawback of lower polymerization activity and shorter catalyst lifetimes. Polymerization of α-olefin is an exothermic reaction, and when producing polyα-olefin industrially, it is necessary to effectively remove the polymerization heat, and generally several polymerization tanks are used for production. Since the unsupported catalyst made of titanium trichloride and organoaluminum compound has a lifespan of several hours to several tens of hours, the residence time of the catalyst is set at an appropriate time and heat is removed in several polymerization tanks as described above. can do. However, the supported titanium catalyst that provides highly stereoregular polyα-olefins has a short lifetime, so
In other words, although the initial polymerization activity is quite large, the polymerization activity decreases quickly, so industrial polyα
- During the production of olefins, it is difficult to control the initial polymerization reaction that generates a large amount of heat, and a solution was needed. Also, its short lifespan means
Another drawback is that the amount of polyα-olefin obtained per unit weight of catalyst is not large enough to significantly streamline the catalyst residue removal process, and an improvement has been desired. The present inventors conducted various studies on increasing the polymerization activity and extending the catalyst life of a supported titanium catalyst that produces highly stereoregular polyα-olefins. The present invention was achieved by discovering a new fact that when trialkylaluminium is added to the polymerization tank when the polymerization activity decreases and almost disappears, the catalyst becomes active again. That is, the method of the present invention provides a composition in which component (A) a magnesium inorganic compound supports a titanium compound, or an electron-donating organic compound, or an electron-donating organic compound and an aluminum halide during or after the supporting operation. and component (B) trialkylaluminum or an electron-donating organic compound or a complex of the electron-donating organic compound and aluminum halide. and, if necessary, component (C).
an electron-donating organic compound or a complex compound of the electron-donating organic compound and aluminum halide (provided that at least one of component (A) and component (B) is an electron-donating organic compound or an electron-donating organic compound); When alpha-olefin is polymerized in the presence of a complex compound with aluminum halide), an electron-donating organic compound or a complex compound of the electron-donating organic compound and aluminum halide is added during the polymerization. This is a method for polymerizing α-olefin in which a composition obtained by treating aluminum trialkyl is added. To further explain the gist of the present invention, Contents: In the presence of a catalyst consisting of components (A) and (B) (excluding combinations in which both components (A) and (B) have not been subjected to modification treatment). A method for polymerizing α-olefin, which comprises adding an additional component during the polymerization. Contents: A catalyst prepared by mixing components (A) and (B) with at least one component of (C) without restriction in the order of addition (provided that both components (A) and (B) have been subjected to modification treatment). ) in the presence of α
- A method for polymerizing α-olefin, characterized in that an additional component is added during the polymerization. However, as the additional component in terms of content or content, a composition obtained by treating aluminum trialkyl with an electron-donating organic compound or a complex compound of the electron-donating organic compound and aluminum halide is used. In the method of the present invention, the titanium compound of component (A) and component (B) are combined to form a polymerization catalyst, and the additional component trialkylaluminum is said to have a so-called promoter effect. Titanium compounds and trialkyl compounds can be used as polymerization catalysts for polyolefins, but in order to polymerize α-olefins such as propylene into industrially useful polymers, the stereoregularity must be controlled to create so-called isotactic polymers. There is a need to. Ingredient (A) and/or ingredients for this purpose
Polymerization is carried out by modifying (B) with an electron-donating organic compound or a complex compound of the electron-donating organic compound and aluminum halide, or by further adding component (C). On the other hand, the organoaluminum compound and the electron-donating organic compound or the complex compound of the electron-donating organic compound and aluminum halide react. For example, triethylaluminum and ethyl benzoate This reaction occurs, and the cocatalyst AlEt ₃ and ethyl benzoate used to control stereoregularity are wasted for purposes other than polymerization. Furthermore, the reaction rate between the two is extremely fast, and the reaction products () and () are not effective as cocatalysts or stereoregularity controllers. As the ratio of ethyl benzoate increases in the polymerization system, the stereoregularity is high but the activity is low, and as the fraction of triethylaluminum increases, the activity increases but the stereoregularity decreases significantly. If a large amount of electron-donating organic compounds are present in the system, trialkylaluminum may be the only additional component; however, if the concentration of electron-donating organic compounds in the system becomes low, the balance between the two will be disrupted and the resulting polymer will have a steric effect. It is inevitable that the regularity will be drastically reduced. In order to prevent this, it is effective to use a composition obtained by treating aluminum trialkyl with an electron-donating organic compound or a complex compound of an electron-donating organic compound and aluminum halide as an additional component. By the method of the present invention, it is possible to significantly extend the activity duration of the catalyst, and as a result, per unit weight of component (A) and per unit weight of titanium metal contained in component (A). Since the amount of produced polymer can be increased, it has become possible to simplify the post-treatment step for removing catalyst residues, and it has also become possible to improve the polymerization activity and the crystallinity of the produced polymer in a well-balanced manner. In the present invention, "modified" refers to component (A), in which an inorganic magnesium compound and/or titanium compound is combined with an electron-donating organic compound and/or a halogen during the preparation process of component (A). It refers to contacting a complex with aluminum oxide (hereinafter abbreviated as a modifier), or contacting a composition consisting of an inorganic magnesium compound and a titanium compound, which are components (A), with a modifier after preparation. In addition, component (B) refers to bringing the trialkylaluminium and a modifier into contact. Component (A) of the catalyst used in the method of the present invention is a composition in which a titanium compound is supported on a magnesium inorganic compound, or an electron-donating organic compound, or an electron-donating organic compound and a halogen compound during or after the supporting operation. This is a composition obtained by adding a complex with aluminum chloride. The magnesium inorganic compound used is preferably magnesium halide, magnesium hydroxyhalide, magnesium oxide, or the like. As the titanium compound, titanium tetrachloride or titanium trichloride is used as a starting material. Various known methods can be used to support the titanium compound on the magnesium inorganic compound, and typical examples include the following. The mode of support may be physical or chemical. (1) A method of co-pulverizing a magnesium inorganic compound with a titanium compound: This is a method of co-pulverizing the above-mentioned magnesium compound and the above-mentioned titanium compound. At this time, various metal compounds, silicon tetrachloride,
There is no problem in coexisting with polysiloxane and the like. Here, the effect is remarkable if the magnesium inorganic compound, the titanium compound, or both are brought into contact with a modifier in advance and then pulverized, but this method is not limited to this method. good. Here, the pulverization method may be any known method commonly used for preparing the titanium component of the Ziegler-Natsuta catalyst. The grinding operation must be carried out in vacuum or in an inert gas atmosphere, with moisture, oxygen, etc. almost completely excluded. When preparing component (A) by the above co-pulverization, 0.1 to 10wt of metallic titanium is contained in component (A).
It is preferable to adjust the proportion of the raw materials so that the titanium compound is present in the range of %. (2) A method of heat treating a magnesium compound and titanium tetrachloride: This method uses magnesium hydroxychloride, magnesium oxide, magnesium hydroxide, or a modified version of any of these as an inorganic magnesium compound.
This is a method to obtain component (A) by directly mixing it with titanium tetrachloride and heat treating it. (3) Another method for supporting is to prepare a preliminary composition by co-pulverizing a magnesium inorganic compound and a modifier in advance as a modification treatment, and then heat-treat this and titanium tetrachloride to support the composition. It is. Grinding in preparing the above pre-composition by modification treatment is carried out in the same manner as the co-grinding method described in (1). In the method of heat treatment with titanium tetrachloride used in supporting method (2) or (3), the above-mentioned magnesium inorganic compound or a precomposition prepared from a magnesium inorganic compound by a modification treatment is treated with titanium tetrachloride or its inactive form. Suspended in solvent solution from 40 °C
A preferred method is to heat treat the titanium tetrachloride at a temperature of 135° C. and then wash the free titanium tetrachloride with an inert solvent or dry it (if necessary under reduced pressure). (A) obtained by supporting titanium modification treatment through this heat treatment.
The components are preferably prepared to contain 0.1 to 10 wt% of titanium metal. Examples of the trialkylaluminum represented by the general formula AlR ₃ (wherein R represents an alkyl group) using component (B) of the present invention include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butyl Aluminum, triiso-butylaluminum, tri-n-hexylaluminum, etc. are used. In the method of the present invention, a carrier-type titanium catalyst is prepared using the above-mentioned trialkylaluminum or one of these which has been modified by contacting with a modifying agent as component (B). In the combination of components (A) and (B) at that time, at least one of the components (A) or (B) must be a component that has been subjected to the above-mentioned modification treatment. If components (A) and (B) that have not been subjected to modification treatment are combined, the effects of the present invention will not be achieved. In the method of the present invention, used during catalyst preparation
The usage amount of component (B) (hereinafter referred to as the initial usage amount of (B)) can be varied over a wide range, but generally the trialkylaluminium in component (B) is relative to the titanium metal in component (A). The molar ratio used is about 1 to 100, preferably 3 to 70. The electron-donating organic compound used as component (C) in the method of the present invention is an organic compound containing oxygen, sulfur, nitrogen, phosphorus atoms, etc., and complexes of this compound with aluminum halide are also used in the present invention. It will be done. Particularly preferred are organic acid esters or complexes of organic acid esters and aluminum halides. As the organic acid ester, aromatic carboxylic acid ester, aliphatic carboxylic acid ester, or alicyclic carboxylic acid ester is used, such as ethyl benzoate, methyl benzoate, propyl benzoate,
Examples include phenyl benzoate, ethyl anisate, ethyl naphthoate, and ethyl hexahydrobenzoate. In addition, the complex of an electron-donating organic compound and aluminum halide used as component (C) can be prepared by a conventional method, for example, by mixing the above components and aluminum halide, or by heating the mixture. The aluminum halide used in this case is preferably aluminum chloride or aluminum bromide. The modifier used in the present invention and the above component (C) may be the same compound or may be different compounds. Next, details of the additional component that characterizes the present invention, that is, the method of starting the polymerization of α-olefin using the catalyst prepared as described above and then adding the additional component will be explained in detail. The amount of the component added during polymerization is generally 0.3 to 5 times the initial amount of (B) mentioned above, preferably
The amount is 0.5 to 3 times the amount, but there is no particular reason to limit it. Further, the addition method may be continuous addition, all-in-one addition, or addition in several portions. In the conventional method, the influence of the Al/Ti molar ratio is large.
If the Al/Ti molar ratio is high, the activity will be high but the crystallinity of the produced polymer will be low; if the Al/Ti molar ratio is small, the crystallinity of the produced polymer will be high but the activity will be low, and the activity decreases rapidly over time. Therefore, it is difficult to balance the activity and the crystallinity of the produced polymer. However, in the present invention, the deactivation of the catalyst can be prevented by adding an additional component during polymerization, so both the activity of the catalyst and the crystallinity of the produced polymer can be maintained at a high level. This method has great industrial significance because it can prevent the disadvantages of a rapid reaction in which it is difficult to remove the reaction heat at the initial stage of polymerization and a rapid decrease in activity thereafter. On the other hand, as shown in the comparative example below, α-
Catalysts consisting of titanium trichloride and diethylaluminum monochloride used for olefin polymerization, i.e., if at least one of the components (A) or (B) is not a supported catalyst that has been subjected to a modification treatment, this product is used. The effect of the invention is not recognized. The method of the present invention is effective for α-olefin polymerization using a carrier-type titanium catalyst in which at least either (A) or (B) has been subjected to a modification treatment. In particular, as shown in Example 1 (1), magnesium halide is modified by co-milling with a complex of aluminum halide and an organic acid ester,
When this is then heat-treated with titanium tetrachloride to support titanium and the resulting composition is used as component (A), it is possible to maintain high activity and high crystallinity, which particularly extends the life of the catalyst. Therefore, the effects of the present invention are best exhibited. The method of the present invention can be used for homopolymerization of α-olefins having 3 to 12 carbon atoms, copolymerization of α-olefins with each other, or copolymerization of α-olefins with each other or with ethyl. Examples of the α-olefin include propyl, butene-1, hexene-1, 4-methylpentene-1, and the like. For the polymerization reaction according to the method of the present invention, conventional methods and conditions commonly used in the technical field can be employed. The polymerization temperature at that time is in the range of 20 to 300℃, preferably 50 to 200℃, and the polymerization pressure is in the range of normal pressure to 200℃.
Atmospheric pressure, preferably in the range of normal pressure to 150 atm.
In the polymerization reaction, generally aliphatic, alicyclic or aromatic hydrocarbons can be used alone or a mixture thereof as a solvent. Among these, propane, butane, pentane, hexane, heptane, cyclohexane, benzene, toluene, etc., or mixtures thereof are preferred. The polymerization can also be carried out by a bulk polymerization method using the liquid monomer itself as a solvent. Furthermore, it can also be carried out by a so-called gas phase polymerization method in which a gaseous monomer and a catalyst are brought into contact. The molecular weight of the polymer produced in the method of the present invention varies depending on the reaction mode, catalyst system, and polymerization conditions, but can be controlled, for example, by adding hydrogen, alkyl halides, dialkyl zinc, etc., as necessary. can. Examples of the present invention are shown below. Example 1 (1) Preparation of catalyst A vibratory mill equipped with a grinding pot having an internal volume of 600 ml and containing 80 steel balls with a diameter of 12 mm was prepared. Add anhydrous magnesium chloride to this pot in a nitrogen atmosphere.
A preliminary composition was prepared by charging 20.0 g of aluminum chloride and 10.0 g of a complex of aluminum chloride and ethyl benzoate and grinding for 20 hours. 10 g of the above preliminary composition and 200 ml of titanium tetrachloride were placed in a 300 ml round bottom flask under a nitrogen atmosphere, stirred at 80° C. for 2 hours, and then the supernatant liquid was removed by decantation. Next, 200 ml of n-heptane was added, the mixture was stirred at room temperature for 30 minutes, and the supernatant liquid was removed by decantation. The washing operation was repeated seven times. Further, 200 ml of n-heptane was added to obtain a slurry of a titanium compound-supported composition (component (A) of the present invention). This corresponds to example (2) of the titanium supporting method. A part of this was sampled, n-heptane was evaporated, and analysis revealed that the Ti content of the composition was 1.20wt% and the Cl content was 64.6wt%.
%, Mg content 18.5wt%, ethyl benzoate content
The content was 12.1 wt%, and the specific surface area was 130 m ² /g. Next, in a SUS-32 autoclave with an internal volume of 2, under a nitrogen atmosphere, 1 ml of n-heptane, 0.15 ml (1.05 mM) of ethyl benzoate as the (C) component, and 0.10 ml of triiso-butylaluminum as the (B) component.
(0.4mM), and component (A) 0.08g (titanium atom equivalent)
0.02mg. Atom) was charged to prepare the catalyst used in the above procedure. (2) Polymerization of propylene After the nitrogen in the autoclave was evacuated using a vacuum pump, hydrogen was charged so that the gas phase partial pressure was 0.3 Kg/ ^cm2 , and propylene was charged to reduce the pressure in the gas phase. It was set to 2Kg/cm ²・G. Heat the contents of the autoclave and increase the internal temperature to 70℃ after 5 minutes.
Polymerization was continued for 2 hours while charging propylene to maintain the polymerization pressure at 5 kg/cm ² ·G at . At 20 minute intervals from the start of polymerization, an additional component of the invention is
A solution of 0.05 ml of triiso-butylaluminum and 0.01 ml of ethyl benzoate mixed with 20 ml of n-heptane was added five times. After cooling the autoclave, unreacted propylene was purged and the contents were taken out, filtered and dried under reduced pressure at 60°C to obtain 90.0 g of white powdery polypropylene powder. The ratio of the boiling n-heptane extraction residual polymer (hereinafter abbreviated as powder) to this powdered polypropylene powder is 96.8wt%, and the bulk specific gravity is 96.8wt%.
The intrinsic viscosity was 1.62 dl/g (measured at 135° C. with tetralin solvent, the same applies hereinafter). On the other hand, 1.2 g of n-heptane soluble polymer (amorphous polypropylene) was obtained by concentrating the liquid.
The ratio of boiling n-heptane extraction residual polymer to the total produced polymer (hereinafter abbreviated as total) is 97.5wt
It was %. The polymerization activity of the catalyst in this polymerization reaction is 43Kg/g-
Ti.hr, and the amount of polypropylene obtained is 85Kg/
It was g-Ti. In order to compare the change in polymerization rate with others, the propylene blowing rate (g/min) at t minutes after the start of polymerization is expressed as Vt, and the conditions for maintaining the reactor internal pressure at 5 Kg/cm ² G in this polymerization reaction. in,
V ₅ = 2.0, V ₆₀ = 1.0, and V ₁₂₀ = 0.5 (the meanings of Vt are the same for each example below). Comparative Example 1 Table 1 shows the results of an experiment conducted in the same manner as in Example 1 except that ethyl benzoate was not used as an additional component and only triisobutylaluminum was added, but otherwise the conditions were the same. Comparative Examples 2 to 4 In the method of Example 1, triiso which is component (B)
- An experiment in which polymerization was carried out in the same manner as in Example 1 (Comparative Example 2) and the method of Example 1 except that the divided addition of butylaluminum and ethyl benzoate was omitted.
An experiment in which polymerization was carried out in the same manner as in Example 1 except that the total amount of the initial usage amount and the divided addition amount of triiso-butylaluminum, which is the component (B), was initially added, and the divided addition was omitted (Comparative Example 3) ) and the method of Example 1 except that only ethyl benzoate was added without using triisobutylaluminum as an additional component, and the other conditions were exactly the same, and Table 1 shows the results.

【table】

[Table] Example 2 Polymerization was carried out in exactly the same manner as in Comparative Example 1 for 2 hours, and then 0.05 ml of triiso-butylaluminum and 0.01 ml of ethyl benzoate were mixed with 20 ml of n-heptane at 20-minute intervals. 20 ml of the solution was added and polymerization was carried out for an additional 100 minutes, for a total of 3 hours and 40 minutes.
The experimental results are shown in Table 2. Comparative Example 4 Table 2 shows the results of repeating the experiment under exactly the same conditions as in Example 2 except that ethyl benzoate was not added as an additional component and triiso-butylaluminum was used. This result shows that compared to the method of Example 2, the total amount of produced polymer is lower.

【table】

[Table] Example 3 Same as Example 1 except that 0.292 g (1.05 nM) of a complex of benzoic acid polymer and aluminum chloride was used in place of ethyl benzoate, component (C). Table 3 shows the results of polymerization carried out in the same manner as above. Comparative Example 5 Table 3 shows the results of an experiment conducted in the same manner as in Example 3, except that ethyl benzoate was not used as an additional component and only triiso-butylaluminum was used, but otherwise the conditions were exactly the same.

【table】

[Table] Example 4 (1) Preparation of catalyst Magnesium chloride 22.8g and ethyl benzoate 7.19g
- was co-pulverized to obtain a preliminary composition in the same manner as in Example 1, then heat treated with titanium tetrachloride in the same manner as in Example 1, and washed with n-heptane with a titanium content of 1.10 wt.
% of component (A) was obtained. Next, in a SUS-32 autoclave with an internal volume of 2, 1 part of n-heptane and 0.158g (1.05mM) of methyl p-toluate (B) were added as component (C).
Triethyl aluminum as an ingredient 0.055ml
Polymerization was started in the same manner as in Example 1 except that (0.4mM) and 0.08g of component (A) above were used as catalyst components, and 0.03ml of triethylaluminum and 0.007ml of methyl p-toluate were added 5 times for 20 minutes. It was divided and charged at intervals. The experimental results are shown in Table 4. Comparative Example 6 Table 4 shows the results obtained by omitting the addition of methyl p-toluate, which is added in portions, in the method of Example 4 and adding only triethylaluminum.

【table】 [Brief explanation of drawings]

FIG. 1 is a flowchart showing a method for producing a catalyst used in the polymerization method of the present invention.

Claims (1)

[Claims] 1 Component (A): A composition in which a titanium compound is supported on a magnesium inorganic compound, or an electron-donating organic compound, or an electron-donating organic compound and aluminum halide during or after the supporting operation. A composition obtained by adding a complex compound with aluminum halide, and component (B): Trialkylaluminum is treated with a trialkylaluminum, an electron-donating organic compound, or a complex compound of the electron-donating organic compound and aluminum halide. and, if necessary, component (C): an electron-donating organic compound or a complex compound of the electron-donating organic compound and aluminum halide (provided that component (A) and component (B) (at least one of which is modified with an electron-donating organic compound or a complex compound of an electron-donating organic compound and aluminum halide),
α- characterized in that a composition obtained by treating aluminum trialkyl with an electron-donating organic compound or a complex compound of the electron-donating organic compound and aluminum halide is added during the polymerization.
Method for polymerizing olefins.