JPH0788407B2 - Method for producing propylene polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a propylene polymer. More specifically, a propylene homopolymer is prepared by a gas phase polymerization using a highly active catalyst suitably used for a gas phase polymerization or a slurry polymerization as a modification of the gas phase polymerization or a polymerization method combining bulk polymerization and gas phase polymerization. The present invention relates to a method for producing a copolymer, a random copolymer of propylene and another α-olefin, or a block copolymer. In particular, the slurry polymerization method or bulk polymerization method is followed by propylene and other α in the gas phase.
-It is preferably used when a block copolymer is produced by copolymerizing olefin.

[Conventional technology]

The polymerization method of α-olefins using a so-called Ziegler-Natta catalyst includes a slurry polymerization method carried out in an inert hydrocarbon solvent, a bulk polymerization method carried out in a liquefied monomer such as liquefied propylene, or a gas phase carried out in a gas phase. Polymerization methods are known.

Further, in the production of impact-resistant propylene block copolymers, a method in which the above-mentioned slurry polymerization or bulk polymerization and gas phase polymerization are combined is also known.

Among these polymerization methods, the gas phase polymerization method has advantages that the solvent recovery and purification steps are omitted, and the facilities such as monomer recovery and polymer drying can be greatly simplified.

However, in the gas phase polymerization method, the monomer in the polymerization vessel exists in the gas phase, so the monomer concentration is lower than in the bulk polymerization method, etc., and the reaction rate is generally low, so that a sufficient polymer yield is obtained. Requires a larger reactor volume and longer residence time.

[Problems to be solved by the invention]

As described above, the present inventors have conducted extensive studies for the purpose of improving the polymerization activity in the gas phase polymerization method, particularly, the copolymerization of propylene and other α-olefin, the improvement of the polymerization activity in the block copolymerization and the like. As a result, using a catalyst system comprising a propylene polymer-containing titanium trichloride and an organoaluminum compound obtained by performing a specific treatment on a specific solid titanium trichloride-based catalyst in the presence of a specific silicon compound. The inventors have found that unexpectedly high catalyst efficiency can be obtained by carrying out random copolymerization or block copolymerization of propylene alone or propylene with other α-olefin in the gas phase, and thus arrived at the present invention.

That is, the gist of the present invention is that the aluminum content is 0.15 or less in the atomic ratio of aluminum to titanium, and a solid titanium trichloride-based catalyst complex containing a complexing agent is used in an inert solvent, and an organoaluminum compound and poly After mixing with siloxanes, contact treatment with propylene in the presence of the resulting mixture was carried out to give 1 g of solid titanium trichloride on the complex.
Using a catalyst system comprising propylene polymer-containing titanium trichloride obtained by producing 0.1 to 100 g of propylene polymer, and an organoaluminum compound, containing propylene alone or other α-olefin. It exists in the manufacturing method of the propylene polymer characterized by polymerizing propylene.

[Means for solving problems]

 The present invention will be described in detail below.

The solid titanium trichloride-based catalyst complex used in the present invention,
The aluminum content is an atomic ratio of aluminum to titanium of 0.15 or less, preferably 0.1 or less, more preferably 0.02 or less, and contains a complexing agent.
The content of the complexing agent is 0.001 or more, preferably 0.01 or more in terms of the molar ratio of the complexing agent to titanium trichloride in the solid titanium trichloride-based catalyst complex. Specifically, titanium trichloride, AlR ³ _p X _{3-p in which} the atomic ratio of aluminum to titanium of titanium trichloride is 0.15 or less (wherein R ³ has 1 to 20 carbon atoms).
Hydrocarbon group, X is a halogen atom, _p is a number of 0 ≦ _p ≦ 2) containing aluminum halide and titanium trichloride, and a complexing agent having a molar ratio of 0.001 or more, for example, the formula TiCl ₃ · (AlR ³ _p X _3-p ) _s · (c) _t (In the formula, R ³ is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen atom, and _p is 0 ≦ _p ≦ 2. , C is a complexing agent, _s is a number less than or equal to 0.05, and _t is a number greater than or _equal to 0.001).
In addition to the TiCl ₃ component, AlR ³ _p X _3-p component and complexing agent C component, a small amount of iodine, titanium trichloride in which a part or all of chlorine is replaced with iodine or bromine, or MgCl ₂ , It may include an inorganic solid for a carrier such as MgO or the like, an olefin polymer powder such as polyethylene or polypropylene, or the like. Examples of the complexing agent C include ethers, thioethers, ketones, carboxylic acid esters, amines, carboxylic acid amides, polysiloxanes, etc. Among them, ethers or thioethers are particularly preferable. As the ether or thioether, R ⁴ —O—R ⁵ or R ⁴ —S—R ⁵ (in the formula, R ⁴ , R ⁵
Represents a hydrocarbon group having 15 or less carbon atoms. ). AlR ³ _p X _3-p includes AlCl ₃ , AlR ³ Cl ₂
Etc.

Further, it is particularly preferable that the solid titanium trichloride-based catalyst complex has an X-ray diffraction pattern having a maximum intensity halo at a position (2θ = 32.9 °) corresponding to the strongest peak position of α-type titanium trichloride. Further, it is preferable that the solid titanium trichloride-based catalyst complex is not subjected to a heat history at a temperature exceeding 150 ° C. during the production. Furthermore, the cumulative pore volume between 20 Å and 500 Å is measured by mercury porosimetry.
0.02 cm ³ / g or more particularly 0.03cm ³ /g~0.15 ³ / g which has very fine features pore volume having a pore diameter such that it, in that it is not necessary to remove the amorphous polymer, Especially preferred.

However, such a solid titanium trichloride-based catalyst complex is deposited at a temperature of 150 ° C. or lower from (a) a liquid containing titanium trichloride liquefied in the presence of ether or thioether.

(B) Solid titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound or metallic aluminum can be easily produced by a method such as treatment with a complexing agent and treatment with a halogen compound.

There are the following two methods for obtaining a liquid substance containing liquefied titanium trichloride in the method (a).

(A) A method in which titanium tetrachloride is used as a starting material, and this is reduced with an organoaluminum compound in the presence of an ether or a thioether and, if necessary, a suitable hydrocarbon solvent.

(B) A method of treating solid titanium trichloride as a starting material with ether or thioether in the presence of a suitable hydrocarbon solvent, if necessary.

There is no particular limitation on the method of precipitating the fine particulate solid titanium trichloride-based catalyst complex, and the liquid material as it is or after adding a hydrocarbon diluent as necessary, a temperature of 150 ° C or lower,
The temperature is preferably raised to 40 to 120 ° C., particularly preferably 60 to 100 ° C., to cause precipitation. When the total number of moles of titanium and aluminum in the liquid titanium trichloride is less than the number of moles of ether or thioether, a liberating agent may be added to promote precipitation. As the liberating agent, titanium tetrachloride and aluminum halides such as aluminum trihalide and alkylaluminum dihalide are preferable. The amount of liberating agent used is 5 times that of titanium in the liquid.
It is preferably not more than the molar amount.

As the complexing agent in the method (b), the complexing agent C is mentioned above.
The same is also exemplified. Examples of the halogen compound include titanium tetrachloride and carbon tetrachloride. The complexing agent treatment and the halogen compound treatment may be carried out simultaneously, but the complexing agent treatment may be carried out first, and then the halogen compound treatment may be carried out. The complexing agent treatment is usually performed in a diluent in which solid titanium trichloride is added to TiCl _{3 in an amount} of 0.2 to
Add 3 mole times complexing agent and carry out at a temperature of -20 to 80 ° C. After the treatment with the complexing agent, it is preferable to separate and wash the obtained solid. Halogen compound treatment is usually performed in a diluent
Perform at a temperature of 10 to 50 ° C. The amount of the halogen compound used is usually 0.1 to 10 mol times, preferably 1 to 10 times the amount of TiCl ₃ .
It is 5 molar times. After the treatment with the halogen compound, it is preferable to separate and wash the obtained solid.

In the present invention, the solid titanium trichloride-based catalyst complex obtained as described above is mixed with an organoaluminum compound and polysiloxanes in an inert solvent. The organoaluminum compound used as the cocatalyst at this time has the general formula ▲ AIR ⁶ _m ▼ X _3-m (2) (wherein R ⁶ is a saturated or unsaturated group having 1 to 20 carbon atoms). A hydrocarbon group, X is a halogen atom, and _m is 1.5 ≦ _m <3.). Specific examples of this include dimethyl aluminum chloride,
Alkyl aluminum halides such as diethyl aluminum chloride, diethyl aluminum bromide, ethyl aluminum sesquichloride, etc., and mixtures thereof can also be used. Of these, preferred is dialkyl aluminum halide, and particularly preferred is diethyl aluminum chloride.

The polysiloxanes used in the present invention are polysiloxanes having a chain or cypro structure, that is, the general formula (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, an aryloxy group or a halogen.) A silicon compound having a repeating unit represented by , With a degree of polymerization of 1 to 3000.

Specifically, for example, octaethylcyclotetrasiloxane [Si (C ₂ H ₅ ) ₂ O] ₄ , dimethylpolysiloxane [Si
(CH ₃ ) ₂ O] _m , methylethylpolysiloxane [Si (C
H ₃ ) (C ₂ H ₅ ) O] _m and other alkyl siloxane polymers;
Hexa-phenylalanine cyclotrisiloxane _{[Si (C 6 H 5) 2} O ]
_3, diphenyl polysiloxane _{[Si (C 6 H 5) 2} O ] aryl siloxane polymers such as _m, diphenyl hexamethyl tetrasiloxane (CH _{3) 3} SiO _{[Si (C 6 H 5) 2} O ] ₂ Si (C
H ₃ ) ₃ , methylphenyl polysiloxane [Si (CH ₃ ) (C
₆ H ₅ ) O] _{m and} other alkylaryl siloxane polymers; 1,
7-dichlorobenzene octamethyltetrasiloxane (CH _{3) 2} ClSiO [Si (CH _{3) 2} O] ₂ Si (CH _{3) 2} haloalkyl siloxane such as Cl; dimethoxy polysiloxane [Si
Examples include alkoxysiloxane polymers such as (OCH ₃ ) ₂ ] _m and diethoxypolysiloxane [Si (OC ₂ H ₅ ) ₂ ] _m ; and organic polysiloxanes such as diphenoxypolysiloxane polymers. Here, _m represents a number of 1 to 3000.

As the polysiloxanes of the present invention, compounds generally called silicone oils can be used and have a viscosity of 0.5 to 2 × 1.
0 Commercially available silicone oils and the mixtures of ⁶ centistokes are preferably used. Specific examples thereof include Shin-Etsu Silicones K50, KF69, and KF96 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd.

The inert solvent used for mixing the solid titanium trichloride-based catalyst complex, the organoaluminum compound, and the polysiloxane may be the same as or different from the solvent used for preparing the solid titanium trichloride. An inert hydrocarbon solvent such as an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon used for ordinary olefin polymerization is used. Normal hexane, normal heptane, cyclohexane, benzene and toluene are preferably used.

Although the amount of the solid titanium trichloride-based catalyst complex dispersed in the above-mentioned inert solvent is not critical, it is preferably within a certain concentration range. Usually, it is preferable that the amount of titanium trichloride in the inert solvent 1 is in the range of 1 to 100 g, preferably 5 to 50 g. If it is too low, the volume of the reactor required for this treatment becomes excessive, which is industrially disadvantageous. Is. If it is too high, a heterogeneous reaction due to poor mixing will be caused and the effect of the present invention will not be sufficiently exerted. However, a strong concentration that can be usually carried out within a range where stirring and mixing are sufficiently performed is selected.

The amount of the organoaluminum compound used is usually 0.1 to 10 mol ratio, preferably 0.2 to 2 mol ratio, based on the solid titanium trichloride.

The amount of the polysiloxanes used is extremely important for exerting the effects of the present invention. The molar ratio of Si in the polysiloxanes to solid titanium trichloride is 0.01 to 5 molar ratio, preferably 0.1 to 2.0 molar ratio. If it is too large, the stereoregularity is lowered and the amount of by-product of the atactic polymer is increased. If it is too small, the effect of the present invention is not sufficiently exhibited.

The temperature at which propylene is blown into the solid titanium trichloride-based catalyst complex, the organoaluminum compound, the polysiloxanes and the inert solvent is not particularly limited as long as it is lower than the temperature of the subsequent main polymerization, but -10 to The temperature is 70 ° C, preferably 5 to 60 ° C, more preferably 25 to 50 ° C. If the treatment temperature is too high, the yield of the crystalline polymer obtained when polymerizing the obtained propylene polymer, catalytic propylene containing tin trichloride, that is, the main polymerization is insufficient. If the treatment temperature is too low, the temperature difference from the cooling water in the treatment tank becomes small, which is industrially disadvantageous in terms of heat removal.

In the present invention, propylene is introduced into the liquid phase part or the gas phase part of the reactor containing the solid titanium trichloride-based catalyst complex, the inert solvent, the organoaluminum compound, and the mixture of the polysiloxanes. The introduction speed is usually 0.1 to 10 kg per hour, preferably 0.2 to 5 kg per 1 kg of solid titanium trichloride.
Is. If the introduction rate is too high, it becomes difficult to control the reaction temperature, and if it is too low, the treatment time becomes long, which is industrially undesirable.

By the contact treatment of the above-mentioned solid titanium trichloride and propylene, a propylene polymer is produced, and by this contact treatment, 0.1 to 100 g, preferably 0.2 per 1 g of solid titanium trichloride.
~ 10g Propylene polymer is produced.

In the present invention, hydrogen is not necessarily required to be present in the above-mentioned propylene contact treatment, and even if hydrogen is not used, a molded product from the polymer produced by the main polymerization does not have a fiber. However, adding hydrogen is also included in the scope of the present invention.

Further, in the present invention, a small amount of other α-olefin such as ethylene and butene-1,4-methylpentene-1 may be used in combination with the introduced propylene.

The propylene polymer-containing titanium trichloride produced by the above treatment can also be used for the main polymerization as it is as a slurry containing unreacted materials, inert solvents, etc., but usually from the liquid phase decantation, excess, centrifugation Etc., and the like, and the solvent is further added to wash it several times. As the solvent, it is advantageous to use the inert hydrocarbon solvent used in the propylene contact treatment.

As described above, the propylene polymer-containing titanium trichloride used in the method of the present invention is obtained, and this is added to the polymerization of propylene (main polymerization) as a catalyst by newly adding an organoaluminum compound.

Although compounds can be used in terms of the main organoaluminum compound is a co-catalyst added in the polymerization the above pretreatment those mentioned in step i.e. the formula (2), the general formula _{▲ AlR 7 l ▼ Cl 3-} l ( In the formula, R ² represents a hydrocarbon group having 1 to 20 carbon atoms, and _l is
Indicates a number from 1.9 to 2.1. ) The compound represented by Of these, diethyl aluminum chloride in which R ⁷ is represented by an ethyl group and 1 is 2 can be sufficiently used, but a normal propyl group or a normal hexyl group is particularly preferable as R ⁷ .

The working amount of the organoaluminum compound is usually 0.1 to 100 mol times, and preferably 2 to 10 mol times, with respect to the titanium compound of the propylene polymer-containing titanium trichloride.

In the propylene polymerization method of the present invention, a known third component such as an electron-donating compound or an aromatic compound may be added and used in addition to the catalyst composed of the propylene polymer-containing titanium trichloride and the organoaluminum compound described above. .

In the main polymerization of propylene, the propylene polymer-containing titanium trichloride and the organoaluminum compound (a third component may be added if necessary) are simply mixed and used for the polymerization, but the mixing method is arbitrary. Good. As the polymerization method in the main polymerization, known slurry polymerization, gas phase polymerization or the like can be carried out, but the effect in the gas phase polymerization is particularly greatest. These polymerization methods may be either continuous or batchwise, and the reaction conditions are 1 to 100 atm, preferably 5 to 40 atm, and 50 to 90 ° C, preferably 60 to 80 ° C. In the slurry polymerization, the same solvent as the inert solvent used in the pretreatment step of titanium trichloride is used as a polymerization medium, and specifically, hexane, heptane, cyclohexane, benzene, toluene, pentane, butane, propane, etc. Hydrocarbons may be mentioned, and propylene itself may be used as a medium. Further, as a method for controlling the molecular weight of the produced polymer, it is also possible to appropriately add a known molecular weight regulator such as hydrogen or diethylzinc to the polymerization reaction.

Although propylene alone may be polymerized in the main polymerization of the present invention, propylene and other α-olefins may be used in combination. The other α-olefins are ethylene, butene-1, 4-methylpentene-1, etc., as in the pretreatment step, and the amount thereof is such a small amount that the product does not lose its properties as a propylene polymer, For example, it is 10% by weight or less with respect to propylene.

When the propylene polymer-containing titanium trichloride as described above is used as a catalyst component and propylene is polymerized according to the method of the present invention, high catalyst efficiency can be obtained.

〔Example〕

Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples without departing from the gist thereof.

FIG. 1 is a flow chart for facilitating the understanding of the technical contents included in the present invention, and the present invention is not limited by the flow chart unless departing from the gist thereof.

In the examples and comparative examples, the catalyst efficiency (CE) is the polypropylene production amount (g) per 1 g of solid titanium trichloride. The CE was calculated by making a pressed piece from the produced polymer powder and quantifying the Ti content by fluorescent X-ray analysis.

Example 1 (A) Preparation of immobilized titanium trichloride At room temperature, purified toluene 5.15 was placed in an autoclave with a capacity of 10 that had been sufficiently replaced with nitrogen, and with stirring, 651 g (5.0 mol) of n-butyl ether and 949 g (5.0 g of titanium tetrachloride). Mol) and 286 g (2.4 mol) of diethylaluminum chloride to give a brown homogeneous solution. Then, the temperature was raised to 40 ° C. After the lapse of 3 minutes, precipitation of purple fine granular solid was observed, but the temperature was kept at 40 ° C. for 2 hours, then 315 g of TiCl ₄ was further added and the temperature was raised to 98 ° C. After holding at 98 ° C for about 1 hour, the granular purple solid was separated and washed with n-hexane to obtain about 800 g of solid titanium trichloride.

(B) Production of Titanium Trichloride Containing Propylene Polymer Purified in 10 autoclaves sufficiently replaced with dry nitrogen n-
Add 5 hexanes and add diethyl aluminum chloride
195 g and 250 g of the solid titanium trichloride obtained in (A) above were charged as TiCl ₃ and 60 g of Shin-Etsu Silicone KF96 (CS20) (viscosity (25 ° C.) 20 centistokes) manufactured by Shin-Etsu Chemical Co., Ltd. as polysiloxanes. The temperature was kept at 40 ° C. and propylene gas at 250 ° C. was blown into the liquid phase for about 1 hour for contact treatment.

Next, the solid component was allowed to settle, the supernatant was removed by decantation, and the solid component was washed several times with n-hexane to obtain a propylene polymer-containing titanium trichloride.

(C) Production of Propylene Block Copolymer Co-catalyst diethylaluminium monochloride 1.3 mmo in an induction-stirring autoclave having a volume of 2 and substituted with dry nitrogen.
1, hydrogen gas of 1.2 kg / cm ² and liquefied propylene of 700 g were charged. The temperature of the autoclave was raised, and when the internal temperature reached 70 ° C., 20 mg of nitrogen was introduced as the TiCl ₃ containing the propylene polymer-containing titanium trichloride obtained in (B) above to initiate the polymerization reaction. After 3 hours, unreacted propylene was quickly purged, and 20 g of polymer powder was sampled under a purified nitrogen atmosphere. Subsequently, a propylene-ethylene mixed gas was supplied to this reactor, the gas phase gas composition was propylene / (propylene + ethylene) = 65 mol%, and the pressure was 15 kg / cm ² · G.
The gas phase polymerization reaction was continued at 80 ° C. for 1 hour while adjusting to 1.

After the reaction was completed, the unreacted monomer gas was purged to obtain 318 g of a powdery polypropylene block copolymer.

The catalyst efficiency (CE) from the Ti content analysis in the polymer by fluorescent X-ray was 13,500 (g
-PP / g-TiCl _3), the final polymer product is 17,300 (g- polymer / g-TiCl _3), the catalytic efficiency of the portion of the copolymer by vapor phase polymerization was found to be 3,800.

Comparative Example 1 (A) Preparation of propylene polymer-containing titanium trichloride Example 1 except that the solid titanium trichloride obtained in Example 1 (A) was used and no silicone oil was added.
A propylene polymer-containing titanium trichloride was prepared in exactly the same manner as in (B).

(B) Production of Propylene Block Copolymer Block copolymerization was performed in the same manner as in (C) of Example 1 except that the propylene polymer-containing titanium trichloride catalyst obtained in (A) above was used.

The catalyst efficiency (CE) was 13,800 when the homopolymerization was completed, the final polymerization product was 15,600, and the catalyst efficiency of the copolymerization portion by gas phase polymerization was 1,800.

Examples 2-3 (A) Preparation of propylene polymer-containing titanium trichloride In Example 1 (B), Shin-Etsu Silicone KF96 (CS-20)
A propylene polymer-containing titanium trichloride was prepared in the same manner as in Example 1 (B) except that the addition amount of was changed.

(B) Production of Propylene Block Copolymer Block copolymerization was performed in the same manner as in (C) of Example 1 except that the propylene polymer-containing titanium trichloride catalyst obtained in (A) above was used. Table 1 shows.

Examples 4 to 5 (A) Preparation of propylene polymer-containing titanium trichloride Example 1 (B) Example 1 (B) except that the silicone compounds shown in Table 1 were added in place of Shin-Etsu Silicone KF96.
A solid titanium trichloride catalyst was obtained in the same manner as in (B).

(B) Production of Propylene Block Copolymer Block copolymerization was performed in the same manner as in (C) of Example 1 except that the propylene-containing titanium trichloride catalyst obtained in (A) above was used, and the results are shown in Table 1. It was shown to.

[Effects of the Invention] The method of the present invention is used for propylene alone or for copolymerization of propylene with other α-olefins, and can be advantageously used because it exhibits a high polymerization activity particularly in copolymerization by gas phase polymerization.

[Brief description of drawings]

FIG. 1 is a flow chart showing one embodiment of the present invention.

Claims (5)

[Claims] 1. A solid titanium trichloride-based catalyst complex having an aluminum content of 0.15 or less in atomic ratio of aluminum to titanium and containing a complexing agent in an inert solvent,
After mixing with the organoaluminum compound and the polysiloxanes, contact treatment with propylene in the presence of the resulting mixture to form 0.1 to 100 g of propylene polymer per gram of solid titanium trichloride on the complex. A method for producing a propylene polymer, which comprises polymerizing propylene alone or propylene containing another α-olefin using a catalyst containing the propylene polymer-containing titanium trichloride thus obtained and an organoaluminum compound. 2. A polysiloxane having a general formula (In the formula, R ¹ and R ² are hydrogen, an alkyl group having 1 to 20 carbon atoms,
It represents an aryl group, an alkoxy group, an aryloxy group or halogen. ) A method for producing a propylene polymer according to claim 1, wherein a silicon compound having a repeating unit represented by the formula (1) and having a degree of polymerization of 1 to 3000 is used. 3. The method for producing a propylene polymer according to claim 1, wherein silicone oil is used as the polysiloxane. 4. The method according to claim 1, wherein the polymerization of propylene alone or propylene containing other α-olefin is carried out in a gas phase. A method for producing a propylene polymer. 5. The solid titanium trichloride-based catalyst complex is precipitated at a temperature of 150 ° C. or lower from a liquid material containing titanium trichloride liquefied in the presence of ether. To the method for producing the propylene polymer according to any one of items 4 to 4.