JPS6342646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polymerizing α-olefin or α-olefin and ethylene in a gas phase.

Polymerization of α-olefins such as propylene using Ziegler-Natsuta catalysts (including catalyst systems in which one component is a catalyst consisting of a transition metal supported on a carrier such as MgCl ₂ ) uses an inert solvent such as a hydrocarbon. It is common to use a so-called slurry polymerization method in which the resulting polymer is obtained in the form of a slurry. However, the most widely adopted manufacturing processes currently include catalyst residue removal steps, atactic polymer extraction steps, and large amounts of solvent recovery and purification steps due to market demands regarding the physical and chemical quality of the resulting polymers. The process is complex and significantly increases the cost of the product. In contrast, the so-called solvent-free polymerization method, which does not use a polymerization solvent,
That is, a gas phase polymerization method or a bulk polymerization method using the monomer itself as a solvent can be considered. However, in order to omit the above-mentioned catalyst residue removal step and atactic polymer extraction step by using the solvent-free polymerization method, the catalyst used must be highly active to the extent that the catalyst residue removal step is not necessary, and the atactic polymer must be highly active. It is necessary to have the ability to produce a highly stereoregular polymer that meets the quality required by the market without extracting the polymer, and various improvements have been made to this end. However, bulk polymerization using improved catalysts gives highly stereoregular polymers with good activity, whereas gas phase polymerization has problems, especially in reducing the stereoregularity of the resulting polymer. be. Gas phase polymerization is a process that does not involve any extraction step for atactic polymers, and a reduction in the stereoregularity of the polymer is a major problem.

An object of the present invention is to provide a method for the gas phase polymerization of α-olefins, which yields highly stereoregular polyα-olefins at a high yield per catalyst.

The α-olefin gas phase polymerization method of the present invention comprises at least an activated titanium component containing trivalent or tetravalent titanium and a halogen atom, and a compound having the general formula AlR ¹ nX ₃ -n.
(Here, R ¹ is a C ₁ to C ₁₂ alkyl group, which may be the same or different, X is a halogen, and 1<n≦
3) In the method of vapor phase polymerizing α-olefin using a Ziegler-Natsuta type catalyst containing an organoaluminum compound represented by It is characterized in that hydrogen is added in a liquid state at a weight ratio of 0.001 to 0.2 to the α-olefin polymer present in the polymerization system.

The catalyst used in the method of the present invention is a Ziegler-Natsuta type catalyst containing at least (A) an active titanium component and (B) an organoaluminium compound. The active titanium component (A) is a carrier-type or non-carrier-type titanium component containing at least trivalent or tetravalent titanium and a halogen atom. The organoaluminum compound (B) has the general formula
It is represented by AlR ¹ nX ₃ -n, where R ¹ represents a C ₁ to C ₁₂ alkyl group, and n R ^1s may be the same or different. X represents halogen and n
is 1<n≦3. As such catalysts, those which give highly active and highly stereoregular poly-α-olefins in solvent polymerization or bulk polymerization are generally used in the present invention. For example, a highly active catalyst containing a titanium trichloride catalyst as one component as shown in Japanese Patent Publication No. 53-3356, or supported on a carrier such as magnesium halide as shown in Japanese Patent Application Laid-Open No. 52-151691. A highly active catalyst containing titanium halide as one component can be used.

The hydrocarbons other than α-olefin used in the method of the present invention vary depending on the polymerization conditions, but generally aliphatic compounds having 5 to 12 carbon atoms,
It is preferable to use an alicyclic hydrocarbon, and more specifically n-hexane, cyclohexane, n-heptane, n-nonane, n-decane, etc. can be used. The amount of hydrocarbons other than α-olefin varies depending on the polymerization conditions, but the amount of hydrocarbons present in liquid form in the polymerization reactor varies depending on the polymerization conditions.
It is added in a weight ratio of 0.001 to 0.2 relative to olefin. If the amount added is less than 0.001 weight ratio, there will be almost no effect, and if it is more than 0.2 weight ratio, the effect will not be greater, and the properties of the powder will deteriorate and the processing and carbonization after taking out the powder will be reduced. This is not preferable because hydrogen recovery etc. become a problem.

In the present invention, there are various methods for making a small amount of liquid hydrocarbon present during polymerization, such as by charging a catalyst diluted with an appropriate amount of liquid hydrocarbon into the polymerization vessel, or by adding By mixing α-olefin with an appropriate amount of liquid hydrocarbon and charging the mixture into a polymerization vessel, it is possible to maintain a constant amount of liquid hydrocarbon in the polymerization system. In these cases, it is preferable to add a small amount of liquid hydrocarbon at the beginning, and as the polymerization progresses, the amount of α-olefin polymer present in the polymerization system increases, so the liquid hydrocarbon is added accordingly. .

In addition, in the case of batch polymerization, it is also possible to charge the entire amount of liquid hydrocarbon required, calculated from the final state, at the beginning of the polymerization.

Furthermore, as another method of making liquid hydrocarbons exist during polymerization, for example, powdery polyα-
A core powder is prepared by adhering a Ziegler-Natsuta type catalyst to the surface of olefin, this core powder is charged into a polymerization reactor, and then an appropriate amount of liquid hydrocarbon is sprayed onto the core powder to permeate it into a moist state. After obtaining the core powder, α-
Polymerization can be advanced by pressurizing olefin gas.

During polymerization, esters such as ethyl benzoate and methyl toluate, glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monopropyl ether, and ethers such as diethyl ether and dibutyl ether are used to convert α-olefins using a Ziegler-Natsuta catalyst. A stereoregularity improver used during polymerization can also be used.

The α-olefin used in the method of the present invention includes propylene, 1-butene, etc., and these can be homopolymerized, copolymerized with each other, or copolymerized with ethylene.

The form of the reactor used in the method of the present invention is as follows:
A known reactor for gas phase polymerization can be used.

Polymerization of α-olefin is generally carried out at temperatures between 0 and 100°C.
Preferably the temperature is in the range of 20 to 90℃, and the polymerization pressure is α
- The upper limit is determined by the type of olefin and the polymerization temperature, but it is in the range of normal pressure to 50 atm, preferably normal pressure to 40 atm, and the polymerization pressure is such that α-olefin does not liquefy.

The molecular weight of the polymer produced in the method of the present invention varies depending on the catalyst used and polymerization conditions, but can be limited by adding hydrogen, alkyl halide, dialkylzinc, etc., if necessary.

By using the method of the present invention, highly stereoregular poly-α-olefin containing almost no amorphous poly-α-olefin that adversely affects the physical properties of the polymer can be obtained in high yield per catalyst, and has practical value. Very expensive.

The present invention will be specifically described below with reference to Examples.

Example 1 (1) Preparation of active titanium component A vibratory mill equipped with four grinding pots each having an internal volume of 4 and containing 9 kg of steel balls with a diameter of 12 mm is prepared. Add 300 g of magnesium chloride, 30 ml of tetraethoxysilane, 1,2 to each pot in a nitrogen atmosphere.
- Added 45 ml of dichloroethane and pulverized for 40 hours.
10 Add 1 kg of the above pulverized material and 5 titanium tetrachloride to an autoclave, stir at 80°C for 2 hours, remove the supernatant liquid by decantation, and then
- Add heptane 8 and stir at 80℃ for 15 minutes, then remove the decantation supernatant and perform a washing operation 7.
After repeating the process several times, 5 more portions of n-heptane were added to obtain an active titanium component slurry. When a part of this activated titanium component slurry was sampled and n-heptane was evaporated and analyzed,
The active titanium component contained 2.5wt% Ti.

(2) Polymerization of propylene Thoroughly dried intrinsic viscosity in an autoclave in step 5 (measured with tetralin solution at 135℃)
1.87, boiling n-heptane extraction residual polymer ratio (hereinafter abbreviated as II) 150g of polypropylene howder with 98.0% is poured into the autoclave, and the air inside the autoclave is evacuated using a vacuum pump, and then dry _N2 is charged into the autoclave. After repeating the operation 5 times, 50 mg of the active titanium component synthesized in (1) above and diethylaluminium chloride were added under a N ₂ stream.
0.24 ml, 0.12 ml of methyl P-toluate, and 0.10 ml of triethylaluminum diluted in 40 ml of n-heptane were charged while stirring the powder, and propylene was charged to 5 kg/cm ³ -G, and then hydrogen was added. After charging 3N of the autoclave, the autoclave was heated with hot water and the temperature was raised to 75°C, and propylene was charged so that the concentration was 28Kg/cm ² -G. On the other hand, 0.30 ml of triethylaluminum diluted with 100 ml of propylene was continuously charged at a rate of 100 ml every 2 hours immediately after the temperature inside the autoclave was raised to 75°C. After continuing polymerization for 2 hours while maintaining 28 kg/cm ² -G at 75°C, unreacted propylene was purged and the contents were taken out. The activity corrected for the powder charged before polymerization (i.e. obtained by gas phase polymerization) was 4800 g/g - active titanium catalyst.
The corrected II was 95.7%, and the corrected limiting viscosity was 1.51.

Comparative Example 1 Using the active titanium component synthesized in Example 1 (1), polymerization was carried out in the same manner as in Example 1 (2) except that each catalyst component was diluted with 40 ml of n-butane. The corrected activity was 4100 g/g-active titanium catalyst/hour, the corrected II was 92.8%, and the intrinsic viscosity was 1.56.

Comparative Example 2 Using the active titanium component synthesized in Example 1 (1), polymerization was carried out in the same manner as in Example 1 (2) except that each catalyst component was diluted with 5 ml of n-heptane. The corrected activity is 3900g/g-active titanium catalyst/hour, the corrected II is 91.9%, and the corrected limiting viscosity is
It was 1.52. In this comparative example, 5 ml of n-heptane
In the autoclave No.5, at 75℃, the entire amount is vaporized and does not exist in liquid form.

Example 2 Using the active titanium component synthesized in Example 1 (1), each catalyst component was diluted in 10 ml of n-heptane and an additional 0.30 ml of triethylaluminum was dissolved in a mixture of 50 ml of n-heptane and 50 ml of propylene. Polymerization was carried out in the same manner as in Example 1 (2) except that The corrected activity is 4500g/g-active titanium catalyst/hour and the corrected 95.4% corrected intrinsic viscosity is 1.48
It was hot.

Example 3 In the same manner as in (2) of Example 1, as a catalyst,
As the active titanium component, 100 mg of titanium trichloride catalyst (TGY-24) manufactured by Marubeni Solvay and 0.6 ml of diethylaluminum chloride diluted in 40 ml of n-heptane were used, and the amount of hydrogen used was 5.5 Nl charged.
Polymerization was carried out at a temperature of 4 hours at a polymerization pressure of 24 kg/cm ² -G. The corrected activity was 2400 g/g-active titanium catalyst/hour, the corrected II was 94.0%, and the corrected intrinsic viscosity was 1.65.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 3, except that 40 ml of n-butane was used instead of 40 ml of n-heptane. Corrected activity is 2200g/g-active titanium catalyst/time;
Corrected II is 92.4%, corrected limiting viscosity is 1.63
It was hot.

Example 4 50 mg of active titanium component synthesized in (1) of Example 1,
Diethylaluminum chloride 0.24ml, methyl P-toluate 0.12ml, triethylaluminum
0.10 ml diluted with 10 ml of n-heptane was charged into the autoclave No. 5 under a nitrogen stream, and then 500 g of liquid propylene was charged, and after further charging 3 Nl of hydrogen, the autoclave was heated with hot water.
After raising the temperature to 75°C, polymerization was carried out for 20 minutes. When excess propylene was purged and the contents were taken out, the yield per active titanium component was 1800 g/g-active titanium catalyst, II was 96.1%, and the intrinsic viscosity was 1.61. On the other hand, after 20 minutes of polymerization, excess propylene was rapidly purged, and when the internal temperature reached 10 Kg/cm ² G at 60°C, 3Nl of hydrogen and 10ml of n-heptane were charged, and the autoclave was heated. While raising the temperature to 75℃, charge a small amount of propylene, and at 75℃ it becomes 28Kg/cm ² G.
I kept it. Meanwhile, triethyl aluminum 0.30ml
was dissolved in a mixture of 60 ml of n-heptane and 40 ml of propylene and charged at a rate of 100 ml over 2 hours.
After continuing polymerization for 2 hours while maintaining 28 kg/cm ² -G at 75°C, unreacted propylene was purged and the contents were taken out. The yield per active titanium catalyst is
9800 g/g - active titanium catalyst, II was 95.9%, and intrinsic viscosity number was 1.58. Therefore, the activity during gas phase polymerization is 4000 g/g-active titanium catalyst/hour, the intrinsic viscosity is 1.57, and II is 95.9%.

Example 5 Using the active titanium component synthesized in Example 1 (1), polymerization was carried out in the same manner as in Example 1 (2) except that each catalyst component was diluted with 40 ml of toluene instead of 40 ml of n-heptane. I went. The corrected activity was 4850 g/g-active titanium catalyst/hour, the corrected II was 95.9, and the corrected limiting viscosity was 1.58.

Example 6 Using the active titanium component synthesized in Example 1 (1), polymerization was carried out in the same manner as in Example 1 (2) except that each catalyst component was diluted with 40 ml of cyclohexane instead of 40 ml of n-heptane. I went. Corrected activity is 4780g/g-
Active titanium catalyst time, corrected II is 95.7
The corrected intrinsic viscosity number was 1.53.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1 Active titanium component containing at least trivalent or tetravalent titanium and halogen atoms and general formula
A Ziegler containing an organic aluminum compound represented by AlR ¹ nX ₃ −n (where R ¹ is a C ₁ to C ₁₂ alkyl group and may be the same or different, X is a halogen, and 1<n≦3)・In a method for producing a stereoregular poly-α-olefin by vapor-phase polymerizing an α-olefin having 3 or more carbon atoms using a Natsuta-type catalyst, a polymer having 5 carbon atoms other than the above-mentioned α-olefin is used during polymerization. ~12 hydrocarbons, relative to the α-olefin polymer present in the polymerization system.
A method for gas phase polymerization of α-olefin, characterized in that it is added in a liquid state at a weight ratio of 0.001 to 0.2.