JPS6247203B2 - - 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 trichloride and an organoaluminum compound is not necessarily sufficient. In order to improve the stereoregularity of such titanium trichloride-based catalysts, various methods have been proposed for adding various third components to the catalyst system. 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 (wherein, R is a hydrocarbon group having 1 to 20 carbon atoms,
X represents halogen, and n represents a number from 1 to 3. ) A method of polymerizing in the presence of a phosphorus compound represented by ) organoaluminium compounds,
(c) Method using a compound containing one or more electron-donating atoms or electron-donating groups (Japanese Unexamined Patent Publication No. 118486-1986)
No.) etc. are known. However, these methods are effective for titanium trichloride obtained by dissolving titanium trichloride in ether and precipitating it, while the latter is effective for titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound. , when applied to AA type titanium trichloride, 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 a stable complex compound consisting of a specific phosphorus compound and an organoaluminum compound was found to have a significant effect on the polymerization activity and steric properties of AA-type titanium trichloride. The present invention was completed by discovering that this method has an excellent effect on improving regularity. 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. ) is an improved method for polymerizing α-olefins, which comprises polymerizing α-olefins in the presence of a polymerization catalyst obtained by contacting a stable 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, especially 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 (where R and R' are an alkyl group or an aralkyl group having 1 to 18 carbon atoms,
indicates a halogen atom. ), specific examples of which are preferred include diethylaluminum chloride, diisobutylaluminum chloride, diethylaluminium bromide, diethylaluminium iodide, and the like, with diethylaluminum chloride being particularly preferred. Furthermore, the organic phosphorus compound used in the present invention has the 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, Examples include trimethylphenylphosphite, trinonylphosphite, monoethyldiphenylphosphite, monobutyldiphenylphosphite, monooctyldiphenylphosphite, diethylmonophenylphosphite, dibutylmonophenylphosphite, etc. 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) (R ² O)
Specific examples of phosphate compounds represented by (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-mentioned stable 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 after the production, this unstable complex compound decreases with the passage of time and is converted into a stable complex compound. The present inventors have also discovered that the polymerization catalyst obtained by contacting this stable complex compound with AA-type titanium trichloride is superior to the conventional catalyst consisting of AA-type titanium trichloride and an organoaluminum compound. It has been discovered that polymerization activity can be improved with almost no effect on stereoregularity. A stable complex compound of an organoaluminum compound and an organophosphorus compound is obtained by mixing the organoaluminum compound and an organophosphorus compound, and the unstable complex compound formed initially disappears over time and becomes stable. Only complex compounds are left. 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, while the IR spectra of the mixture of (D) and (T) are as shown in Figure 2.
The characteristic absorption peak at wave number 865 cm ^-1 disappears, and a new peak at wave number 850 cm ^-1 is generated [Figure 2 1]. At 40°C, this peak does not change much for about 1 minute after generation, but then it decreases and about 3
After an hour, it decreases to about half, and after one day, it disappears to almost a trace [Fig. 2, 3]. Therefore, in order to obtain the effects of the present invention, DEAC
It is necessary to contact the AA type titanium trichloride after 4 hours or more, particularly preferably 1 day or more, after mixing and TPP. The ratio of the organoaluminum compound and organophosphorus compound used in the present invention is as follows:
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 g mol, preferably 2 to 10 g mol, of the organoaluminum compound per 1 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 a stable 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, in which it is essential to mix the organoaluminum compound and the organophosphorus compound and then contact them with AA-type titanium trichloride. The method of first mixing and AA type titanium trichloride and then mixing an organophosphorus compound, or the method of first mixing an organophosphorus compound and AA type titanium trichloride and then mixing an organoaluminum compound, is described in this book. Does not show the effect of the 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, it is possible to mix the organoaluminum compound and the organophosphorus compound. It is desirable to use the method of mixing as is or dissolving it in α-olefin. Next, the polymerization catalyst obtained by contacting AA type titanium trichloride with the stable 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 a stable complex compound are separately supplied to a polymerization reactor containing α-olefin, and then It is also possible to adopt a method in which the catalyst is contacted 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, butene-1,3-methylpentene-1,4-methylpentene-1, pentene-1, hexene-1, 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 according to the invention in gas phase polymerization processes. Further, the polymerization catalyst used in the present invention is the above α-
As a catalyst for homopolymerization of olefins or random copolymerization using mixtures thereof, or as α
- It can also be used as a catalyst for block copolymerization in which an olefin homopolymer or random copolymer is polymerized with another type of α-olefin 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 40-100℃, preferably
Selected from the range of 50-70°C. The polymerization reaction can be carried out either batchwise or continuously. Furthermore, 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 it exceeds the gist thereof. In the examples, catalytic 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 from 1 in a way that it would break when the stirrer was rotated. I installed it. After purging this autoclave with dry nitrogen, diethyl aluminum 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. Four hours after adding TPP, the stirrer motor was turned on to break the ampoule and polymerization was started. Polymerization was carried out at 70°C for 1 hour.
The polymer obtained by removing unreacted propylene is
The weight was 129.6g, and the CE was 1296. Also, HI is
It was 94.3. FIG. 1 shows the IR spectra of a heptane solution (10% by weight) of DEAC (D) and a heptane solution (10% by weight) of TPP (T) used in the polymerization. Further, these two solutions were mixed so that TPP was 4 mol % with respect to DEAC, and the IR spectrum of the mixed solution after 4 hours was shown in FIG. 2. Examples 2 to 3 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. The results are shown in the table below.

[Table] Furthermore, the IR spectrum 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 after one day is shown in FIG. 2. 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. CE800, HI92.9 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, 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 10 seconds and 10 minutes, and the following results were obtained.

[Table] In addition, Figure 2 shows the IR spectrum after 10 seconds 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. A peak at 850 cm ^-1 is seen, which is thought to be the characteristic absorption of the TPP complex compound.
This peak was reduced to less than half in Example 1, in which DEAC and TPP were brought into contact for 4 hours, as shown in FIG. 2, and in Example 2, in which DEAC and TPP were brought into contact for 1 day, as shown in FIG. DEAC
It is clear that the complex compound of and TPP is unstable and converts to a stable complex compound with the passage of time, and that this stable complex compound is effective in improving catalytic efficiency (CE). Comparative Example 6 In Example 1, instead of bringing DEAC and TPP into contact first, DEAC, TPP, and TiCl ₃ were put into an autoclave all at once and polymerized.
It was CE850 and HI92.9. Comparative Examples 7 to 13 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,
When polymerization was carried out with the contact time with DEAC set to 10 seconds (Comparative Example 13), 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 1237 93.3

[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 diethylaluminium chloride and triphenyl phosphite, and FIG. 3 shows the IR spectra of the stable complex compound used in the present invention.

Claims (1)

[Scope of Claims] 1. (a) titanium trichloride obtained by reducing titanium tetrachloride with metal aluminum and then pulverizing it, and (b) having the general formula RR'Al
18 alkyl groups or aralkyl groups, X represents a halogen atom. ) and an organoaluminum compound with 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.) Polymerization of α-olefin in the presence of a polymerization catalyst obtained by contacting a stable complex compound with an organic phosphorus compound. α− consisting of
Improved polymerization method for olefins.