JPS6247202B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for polymerizing alpha-olefins. More specifically, α-olefin homopolymers or copolymers are produced using a polymerization catalyst consisting of titanium trichloride (so-called AA type titanium trichloride) obtained by reducing titanium tetrachloride with metal aluminum and then pulverizing it and an organoaluminum compound. This invention relates to a method for producing a polymer. Generally, the stereoregularity of α-olefin homopolymers or copolymers using a polymerization catalyst consisting of titanium chloride and an organoaluminum compound is not necessarily sufficient. In order to improve the stereoregularity of such a titanium trichloride catalyst system, methods of adding various third components to the catalyst system have been proposed. For example, in a method for polymerizing α-olefin using a catalyst system consisting of solid titanium trichloride and an organoaluminum compound, aromatic hydrocarbons and general formula P(OR)nX _3-o
(In the formula, R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is a number of 1 to 3.)
82988), (a) a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and further activating it, (b) an organoaluminum compound, and (c) an electron-donating atom or an electron-donating group. A method using a compound containing more than 100% of the total number of compounds (Japanese Unexamined Patent Publication No. 11486/1986) is known. However, these methods
The former is effective for titanium trichloride obtained by precipitating after dissolving in ether, and the latter is effective for titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound, but it is effective for AA type titanium trichloride. When applied, a sufficient improvement in stereoregularity has not been obtained. In particular, the latter (Comparative Example 2) shows that the combination of AA type titanium trichloride catalyst-diethylaluminum chloride-methyl methacrylate has poor polymerization activity and product quality. The present inventors investigated the third component that is effective on AA-type titanium trichloride, and found that an unstable complex compound consisting of a specific organophosphorus compound and an organoaluminium compound has an effect on the polymerization activity of AA-type titanium trichloride. The present invention was completed by discovering that it exhibits an excellent effect in improving stereoregularity. That is, the gist of the present invention is that (a) titanium trichloride obtained by reducing titanium tetrachloride with metal aluminum and then pulverizing it; and (b) titanium trichloride with the general formula RR'Al ~18 alkyl or aralkyl groups, X represents a halogen atom) and an organoaluminum compound of the general formula (R ¹ O) (R ² O) (R ³ O) P or (R ¹ O) (R ² O) (R ³ O) PO (in the formula R ¹ , R ² ,
R ³ represents a hydrocarbon group having 1 to 18 carbon atoms. ) An improved method for polymerizing α-olefins, which comprises polymerizing α-olefins in the presence of a polymerization catalyst obtained by contacting an unstable complex compound with an organic phosphorus compound. The present invention will be explained in more detail below. The AA type titanium trichloride used in the present invention refers to titanium trichloride obtained by reducing titanium tetrachloride with metal aluminum, particularly titanium trichloride containing a eutectic with aluminum trichloride, which is ground in a ball mill. Alternatively, those that have been further heat-treated or those that have been purified to remove impurities contained therein are preferably used. Next, the organoaluminum compound used in the present invention has the general formula RR'AlX (wherein R and R' are an alkyl group or an aralkyl group having 1 to 18 carbon atoms, and X is a halogen atom). Specific examples of organoaluminum compounds include diethylaluminum chloride, diisobutylaluminum chloride, diethylaluminium bromide,
Diethylaluminum iodide and the like are preferred, and diethylaluminium chloride (DEAC) is particularly preferred. In addition, the organic phosphorus compound used in the present invention is
general formula

[expression] or

An organic phosphorus compound of the formula: (wherein R ¹ , R ² and R ³ represent a hydrocarbon group having 1 to 18 carbon atoms),
Specific examples of phosphite compounds of the general formula (R ¹ O) (R ² O) (R ³ O) P include trimethyl phosphite, triethyl phosphite, tributyl phosphite, trioctyl phosphite, triphenyl phosphite, Trimethylphenyl phosphite, trinonylphenyl phosphite, monoethyl diphenyl phosphite, monobutyl diphenyl phosphite, monooctyl diphenyl phosphite, diethyl monophenyl phosphite,
Examples include dibutyl monophenyl phosphite, but especially the general formula

Preferred are triphenyl phosphite compounds of the formula: (wherein R represents hydrogen or an alkyl group or alkenyl group having 1 to 18 carbon atoms), and triphenyl phosphite is particularly preferred. Then (R ¹ O)
Specific examples of phosphate compounds represented by (R ² O) (R ³ O) PO include phosphate compounds corresponding to the phosphite compounds exemplified above;

A triphenyl phosphate compound represented by the formula: (wherein R represents hydrogen or an alkyl group or alkenyl group having 1 to 18 carbon atoms), particularly triphenyl phosphate, is preferred. A feature of the present invention is a polymerization catalyst obtained by contacting the above unstable complex compound of an organoaluminum compound and an organophosphorus compound with AA-type titanium trichloride. That is, when an organoaluminum compound and an organophosphorus compound are brought into contact with each other, an unstable complex compound is first produced, and this unstable complex compound is immediately converted into a stable complex compound and disappears after the production. The present inventors then discovered that this unstable complex compound
The polymerization catalyst obtained by contacting with AA-type titanium trichloride not only has improved stereoregularity but also has higher polymerization activity than the conventional catalyst made of AA-type titanium trichloride and an organoaluminum compound. We have found that this can be improved. An unstable complex compound of an organoaluminum compound and an organophosphorus compound is obtained by mixing an organoaluminum compound and an organophosphorus compound, and disappears over time, leaving only the stable complex compound. For example, a case will be described in which diethylaluminum chloride (DEAC) is used as the organoaluminum compound and triphenyl phosphite (TPP) is used as the organophosphorus compound.
The individual IR spectra of DEAC (D) and TPP (T) are shown in Figure 1, but the IR spectrum of the mixture of DEAC and TPP is as shown in Figure 2.
The peak at a wave number of 865 cm ^-1, which is the characteristic absorption of TPP, disappears and a new peak at a wave number of 850 cm ^-1 is generated [Fig. 2 1], but this peak is almost absent for about 1 minute after generation at 40°C. However, after about 3 hours it decreased to about half [Figure 2 2].
After one day, it almost disappears to just a trace [Figure 2 3]. Therefore, in order to obtain the effects of the present invention, DEAC
After mixing and TPP, it is necessary to contact the AA type titanium trichloride within 4 hours, particularly preferably within 1 minute. The ratio of the organoaluminum compound and organophosphorus compound used in the present invention is 1 mole of the organoaluminum compound:
The amount is 0.001 to 0.5 mol, preferably 0.01 to 0.1 mol. The proportion of the AA type titanium trichloride and the organoaluminum compound used is 1 to 20 gmol, preferably 2 to 10 gmol, of the organoaluminum compound per gram atom of titanium. Next, in the method of the present invention, a polymerization catalyst is prepared by contacting the AA type titanium trichloride with an unstable complex compound of an organoaluminum compound and an organophosphorus compound. A method for simultaneously mixing an organoaluminum compound, an organophosphorus compound, and an AA-type titanium trichloride, which method requires mixing an organoaluminum compound and an organophosphorus compound and immediately contacting the same with AA-type titanium trichloride. A method of first mixing AA-type titanium trichloride and then mixing an organic phosphorus compound, or a method of mixing an organic phosphorus compound and AA type titanium trichloride.
Any method in which titanium trichloride is first mixed and then an organoaluminum compound is mixed does not exhibit the effects of the present invention. It is also possible to use a solvent when mixing the organoaluminum compound and the organophosphorus compound, but when polymerizing α-olefin using a monomer as a solvent, the organoaluminum compound and the organophosphorus compound can be mixed as is. It is preferable to use the method using the method or by dissolving it in α-olefin. Next, the polymerization catalyst obtained by contacting AA type titanium trichloride with the unstable complex compound may be used for polymerization after storage, or it may be used for polymerization immediately. In addition, when performing a polymerization reaction using α-olefin as a solvent, AA-type titanium trichloride and the unstable complex compound are separately supplied to a polymerization reactor containing α-olefin, and the contact is carried out in the polymerization reactor. It is also possible to adopt a method in which the polymer is prepared and used as it is as a polymerization catalyst. In the method of the present invention, α-olefin is polymerized using the polymerization catalyst thus obtained. Examples of the α-olefin include propylene, 1-butene, 1-3-methylpentene, 1-4-methylpentene, 1-pentene, 1-hexene, and mixtures thereof. In particular, mention may be made of propylene or mixtures of propylene with small amounts of other olefins, such as ethylene or butene-1. The polymerization method of such olefins usually uses hexane, heptane, cyclohexane, pentane,
Although the polymerization is carried out in an aliphatic hydrocarbon solvent such as butane, it is also possible to employ a method in which α-olefin itself, such as propylene or butene-1, is used as the polymerization solvent. Furthermore, it is also possible to use the catalyst of the invention in gas phase polymerization processes. The polymerization catalyst of the present invention can also be used as a catalyst for homopolymerization of α-olefins or random copolymerization using a mixture thereof, or as a catalyst for homopolymerization of α-olefins or random copolymerization using α-olefin homopolymers or random copolymers of other α-olefins.
- It can also be used as a catalyst for block copolymerization of olefins or ethylene. Polymerization conditions can be selected from a wide range of commonly used conditions. The pressure may be normal pressure or lower, but in order to obtain an industrially advantageous polymerization rate, 1
~150 atmospheres, preferably 5 to 30 atmospheres. The polymerization temperature is usually selected from the range of 40-100°C, preferably 50-70°C. The polymerization reaction can be carried out either batchwise or continuously. Further, as a method for controlling the molecular weight of the produced polymer, it is also possible to add known molecular weight regulators such as hydrogen and diethylzinc during the polymerization reaction. Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. In the Examples, the catalyst efficiency CE represents the yield (g) of polymer per 1 g of AA type titanium trichloride. The isotactic index HI indicates the percentage of insoluble parts (% by weight) when the polymer is extracted with boiling heptane for 3 hours using a Soxhlet extractor. Example 1 A glass ampoule filled with 100 mg of AA type TiCl ₃ (TiCl ₃ 1/3 AlCl ₃ eutectic) manufactured by Toyo Stouffer was placed in the stainless steel autoclave in 1 in a way that it would break when the stirrer was rotated. I installed it. After purging this autoclave with dry nitrogen, diethylaluminum chloride (hereinafter referred to as
It's called DEAC. ) was added in an amount equivalent to 3 times the molar amount of TiCl ₃ . 800ml liquid propylene and hydrogen
600 ml (under standard conditions) was charged into an autoclave, and then triphenyl phosphite (hereinafter referred to as TPP) corresponding to 4 mol% relative to DEAC was added. Ten seconds after adding TPP, the stirrer motor was turned on to break the ampoule and initiate polymerization. Polymerization was carried out at 70°C for 1 hour. The polymer obtained by removing unreacted propylene is
The weight was 105.8g, and the CE was 1058. Also, HI is
It was 95.3. Heptane solution (10% by weight) of DEAC (D) and heptane solution (10% by weight) of TPP (T) used in polymerization.
Fig. 1 shows the IR spectrum of the sample (% by weight). Furthermore, these two solutions were mixed so that TPP was 4 mol % relative to DEAC, and the IR spectrum of the mixed solution after 10 seconds was shown in FIG. 2. The spectrum of this mixed solution showed a peak at 850 cm ^-1 which was considered to be the characteristic absorption of the complex formed between DEAC and TPP. Examples 2 to 5 In Example 1, the contact time between DEAC and TPP was
Polymerization was carried out in the same manner as in Example 1, except that the time was changed to 30 seconds, 1 minute, 10 minutes, and 3 hours. The results are shown in the table below.

[Table] Further, FIG. 2 shows the IR spectrum after 3 hours of the mixed solution used to measure the IR spectrum of the mixed solution of each heptane solution of DEAC and TPP in Example 1. Comparative Example 1 Polymerization was carried out in exactly the same manner as in Example 1 except that TPP was not used.
It was CE1050 and HI92.6. Comparative Example 2 Instead of first mixing TPP with DEAC in Example 1, it was mixed with TiCl ₃ in advance and sealed in an ampoule with TiCl ₃ , and polymerization was carried out in the same manner as in Example 1. CE860, HI93.0 It was hot. Comparative Example 3 In Comparative Example 1, when the stirrer was rotated to break the glass ampoule and TiCl ₃ came into contact with DEAC, TPP corresponding to 4 mol% relative to DEAC was added and polymerized, resulting in CE905, It was HI92.7. Comparative Examples 4 and 5 Polymerization was carried out in the same manner as in Example 1, except that the contact time between DEAC and TPP was changed to 1 day and 3 days, and the following results were obtained.

[Table] Also, the IR spectrum of DEAC and TPP mixed for one day is shown in Figure 2.3.
The peak at 850 cm ^-1, which is considered to be the characteristic absorption of the TPP complex, almost disappeared. From the above, the complex of DEAC and TPP is unstable, and unless such an unstable complex is used,
It can be seen that there is no improvement effect on HI. Comparative Example 6 In Example 1, instead of bringing TPP and DEAC into contact first, TPP, DEAC, and TiCl ₃ were put into an autoclave all at once and polymerized.
It was CE850 and HI92.9. Comparative Examples 7 to 9 In a hexane solution of _TiCl4 cooled to -5℃
The reduced solid obtained by dropping DEAC over 2 hours was activated with a mixture of n-butyl ether and hexachloroethane at 85° C. for 5 hours to obtain a catalyst solid. When polymerization was carried out using the catalyst solid thus obtained and DEAC without using TPP as in Comparative Example 1, the results were CE4500 and HI95.5 (Comparative Example 7). Next, the above catalyst solid was polymerized in the same manner as in Comparative Example 4 in combination with DEAC and TPP that had been brought into contact with each other for one day.
The HI was 97.0 (Comparative Example 8). Furthermore, when the above catalyst solid was polymerized in the same manner as in Example 1 in combination with DEAC and TPP brought into contact for 10 seconds, CE3720,
The HI was 96.9 (Comparative Example 9). From the above, in the case of TiCl ₃ catalyst obtained by reducing TiCl ₄ with an organoaluminum compound,
It can be seen that although the use of TPP improves the HI, it reduces the activity of the catalyst, and shortening the contact time between DEAC and TPP has no effect on improving the HI. Comparative Examples 10 to 16 Polymerization was carried out in the same manner as in Example 1, except that the compounds shown in the table below were used instead of TPP. The results are shown in the table below.

[Table] Also, regarding methyl methacrylate, DEAC
When polymerization was carried out by changing the contact time to 1 day (Comparative Example 16), the results were CE1015 and HI93.2, and no effect was observed even if the contact time was changed. Examples 6 and 7 In Example 1, polymerization was carried out by changing the ratio of TPP to DEAC. The results are shown in the table below.

[Table] Examples 8 and 9 In Example 1, polymerization was carried out by changing the ratio of DEAC to TiCl ₃ while keeping the ratio of TPP to DEAC constant at 4 mol %. The results are shown in the table below.

[Table] Examples 10 to 12 In Example 1, polymerization was carried out using the organic phosphorus compounds shown in the following table instead of TPP. The results are shown in the table below.

[Table]
12 Triethyl phosphate 1010 94.2

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the steps for preparing a polymerization catalyst according to the present invention. FIG. 2 shows the IR spectra of diethylaluminum chloride and triphenyl phosphite, and FIG. 3 shows the IR spectra of the unstable complex compound used in the present invention.

Claims (1)

[Claims] 1 (a) Titanium trichloride obtained by reducing titanium tetrachloride with metal aluminum and pulverizing it, and (b) general formula
An organoaluminum compound of RR′AlX (wherein R and R′ are an alkyl group or an aralkyl group having 1 to 18 carbon atoms, and X represents a halogen atom) and the general formula (R ¹ O) (R ² O ) (R ³ O) P or (R ¹ O) (R ² O)
(R ³ O)PO (in the formula, R ¹ , R ² , R ³ have 1 to 1 carbon atoms)
Shows 18 hydrocarbon groups. ) An improved method for polymerizing α-olefins, which comprises polymerizing α-olefins in the presence of a polymerization catalyst obtained by contacting an unstable complex compound with an organic phosphorus compound.