JP2695192B2 - Method for producing propylene polymer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION Technical Field The present invention relates to a method for producing a propylene polymer having excellent crystallinity.

2. Prior Art A propylene polymer is a resin having high rigidity and high mechanical strength, but higher rigidity is required for some applications.

Therefore, many attempts have been made to improve the crystallinity by prepolymerization together with the improvement of the polymerization catalyst for the purpose of improving the rigidity of polypropylene, for example, JP-A-60-139731 and JP-A-61-151204. KAISHO No. 61-155404 discloses that the crystallinity of polypropylene in the subsequent main polymerization is increased by preliminarily polymerizing a branched α-olefin, but the rigidity of the product depends on the application. It was still insufficient.

[Summary of the Invention]

SUMMARY OF THE INVENTION The present invention intends to efficiently produce polypropylene having extremely high rigidity by conducting prepolymerization with a combination of a specific catalyst and a specific monomer in advance and then homopolymerizing propylene.

That is, in the method for producing a propylene polymer according to the present invention, a solid titanium catalyst component (A) containing magnesium halide, tetravalent titanium halide and an electron donating compound as essential components and a general formula AlR _n X _3-n ( Where R is 1 carbon
To 12 hydrocarbon residues, X is a halogen or alkoxy group, and n is 0 <n ≦ 3. ) In the presence of a catalyst formed from an organoaluminum compound (B),
In the method for carrying out homopolymerization of propylene, solid titanium catalyst organoaluminum compound and general formula R ¹ R ² _3-n S
i (OR ³ ) _n (wherein R ¹ is a branched hydrocarbon residue, R ² and R ³ are branched or linear hydrocarbon residues,
n is a number of 2 ≦ n ≦ 3. ) In the presence of the organosilicon compound represented by the formula (3), 3-methyl-1-butene is polymerized in an amount of 0.01 to 100 g per 1 g of the solid titanium catalyst component (A). Is.

Effect According to the present invention, polypropylene having extremely high rigidity can be efficiently manufactured.

[Specific description of the invention]

Catalyst Component The method for producing a propylene polymer according to the present invention is characterized mainly in that the titanium-containing solid catalyst component of the Ziegler type catalyst used is one that has undergone a specific prepolymerization step. In other words, the method for producing a propylene polymer according to the present invention comprises the step of carrying out the main polymerization, that is, the homopolymerization of propylene, by preliminarily polymerizing 3-methyl-1-butene. .

The catalyst used in the present invention is formed from the above-mentioned component (A) and the above-mentioned component (B), and falls within the category of Ziegler type catalyst.

Here, "formed from the component (A) and the component (B)" means that the third component which does not unduly impair the effects of the present invention or more preferably the third component which advantageously acts on the present invention. It should be understood that this does not exclude the case of including. In fact, this catalyst, whose component (A) has undergone prepolymerization, is preliminarily polymerized in the presence of a specific silicon compound, and this silicon compound is subsequently introduced into the main polymerization. Therefore, the catalyst in the polymerization (main polymerization) according to the present invention is formed from the components (A) and (B) and this silicon compound. A typical example of such a third component is an electron-donating compound as a so-called external donor, and a catalyst containing such a component constitutes one embodiment of the present invention.

Solid Titanium Catalyst Component (Component (A)) The solid titanium catalyst component (A) used in the present invention is
Magnesium halide, tetravalent titanium halide and electron donating compound are essential components. Here, "to be an essential component" means that, in addition to the case where the solid titanium catalyst component (A) is composed of only these specific three components, at least the effect of the combination of these three components is maintained or It means that additional components may be included unless they are unduly compromised. Such additional ingredients include
For example, a silicon halide compound.

(1) Magnesium halide The magnesium halide is preferably a magnesium dihalide, and magnesium chloride, magnesium bromide and magnesium iodide can be used. More preferably, it is magnesium chloride, more preferably substantially anhydrous.

Further, magnesium halides include magnesium oxide, magnesium hydroxide, hydrotalcite, magnesium carboxylates, alkoxy magnesium, allyloxy magnesium, alkoxy magnesium halides, allyloxy magnesium halides, organic magnesium compounds as electron donating compounds, and halosilanes. Alternatively, it may be magnesium halide obtained by treating with alkoxysilane, silanol, Al compound, titanium halide compound, titanium tetraalkoxide or the like.

(2) Titanium tetravalent halide Preferred tetravalent titanium halide represented by the general formula Ti (OR ⁴ ) _n X _4-n (R ⁴ is a C _{1 to} C ₁₀ hydrocarbon residue, X is a halogen). Among such compounds, it is a tetravalent titanium halide compound with n = 0, 1 or 2. Specifically, TiCl ₄ , Ti (OBu) Cl ₃ , Ti (OBu) ₂ Cl _{2 and the} like can be exemplified, but titanium tetrahalide or mono such as TiCl ₄ and Ti (OBu) Cl ₃ are preferable. It is an alkoxytrihalogenated titanium compound. Particularly preferred is TiCl ₄ .

(3) Electron-donating compound The electron-donating compound is now well known as a modifier for Ziegler type catalysts, and any desired compound can be used in the present invention.

Preferred electron donating compounds for use as so-called "internal donors" in the present invention are esters of polyfunctional compounds selected from the group consisting of polycarboxylic acids, polyhydric alcohols and hydroxy-substituted carboxylic acids. Those suitable as esters of these polyfunctional compounds are, for example, those represented by the following formula.

Here, R ¹ is a substituted or unsubstituted hydrocarbon group,
R ² , R ³ and R ⁴ are hydrogen or a substituted or unsubstituted hydrocarbon group, R ⁵ and R ⁶ are hydrogen or a substituted or unsubstituted hydrocarbon group, preferably at least one of which is substituted or An unsubstituted hydrocarbon group. R ³ and R ⁴ may be linked to each other. Here, the substituted hydrocarbon group includes a hetero atom such as N, O and S, for example, C—O—C, COOR, COOH, OH, SO.
Some have groups such as ₃ H, —C—N—C—, and NH ₂ .

Particularly preferred among these are diesters of dicarboxylic acids in which at least one of R ¹ and R ² is an alkyl group having 2 or more carbon atoms.

Specific examples of preferred polycarboxylic acid esters include (a) diethyl succinate, dibutyl succinate, diethyl methyl succinate, diisobutyl α-methylglutarate, dibutyl methyl malonate, diethyl malonate, diethyl ethyl malonate, isopropyl Diethyl malonate, diethyl butylmalonate, diethyl phenylmalonate, diethyl diethylmalonate, diethyl allylmalonate, diethyldiisobutylmalonate, diethyldinormalbutylmalonate, dimethylmaleate, monooctyl maleate, dioctyl maleate, maleic acid Dibutyl, dibutyl butyl maleate, diethyl butyl maleate, diisopropyl β-methylglutarate, diallyl ethyl succinate, di-2-ethylhexyl fumarate, diethyl itaconate Aliphatic polycarboxylic acid esters such as dibutyl itaconate, dioctyl citraconic acid and dimethyl citraconic acid, (ii) diethyl 1,2-cyclohexanecarboxylate, diisobutyl 1,2-cyclohexanecarboxylate, diethyl tetrahydrophthalate, diethyl nadicate Aliphatic polycarboxylates, such as
(C) Monoethyl phthalate, dimethyl phthalate, methylethyl phthalate, monoisobutyl phthalate, mononormal butyl phthalate, diethyl phthalate, ethyl isobutyl phthalate, ethyl normal butyl phthalate, di-n-propyl phthalate, phthalate Diisopropyl phthalate, di-n-butyl phthalate, di-isobutyl phthalate, di-n-heptyl phthalate, di-2-ethylhexyl phthalate, di-n-phthalate
-Aromatic polycarboxylic acid esters such as octyl, dineopentyl phthalate, didecyl phthalate, benzyl butyl phthalate, diphenyl phthalate, diethyl naphthalene dicarboxylate, dibutyl naphthalene dicarboxylate, triethyl trimellitate, dibutyl trimellitate,
(D) Different carbon polycarboxylic acid esters such as 3,4-furandicarboxylic acid can be used.

Specific examples of preferable polyhydric hydroxy compound esters include 1,2-diacetoxybenzene and
1-methyl-2,3-diacetoxybenzene, 2,3-diacetoxynaphthalene, ethylene glycol dipivalate,
Butanediol pivalate and the like can be mentioned.

Examples of hydroxy-substituted carboxylic acid esters include:
Benzoyl ethyl salicylate, acetyl isobutyl salicylate, acetyl methyl salicylate and the like can be exemplified.

Other examples of the polycarboxylic acid ester that can be supported on the titanium catalyst component include diethyl adipate, diisobutyl adipate, diisopropyl sebacate, di-n-butyl sebacate, di-n-octyl sebacate, and sebacic acid. Esters of long-chain dicarboxylic acids such as di-2-ethylhexyl can be mentioned.

Among these polyfunctional esters, those having a skeleton of the above-mentioned general formula are preferred, and more preferably phthalic acid, maleic acid, substituted malonic acid, etc.
The above-mentioned esters with alcohols, and particularly preferred are the diesters of phthalic acid and alcohols having 4 to 10 carbon atoms.

These electron-donating compound components are used as solid catalyst components (A)
When it is included in the above, it is not always necessary to use these as starting materials, and it is also possible to use a compound that can be converted to these in the process of preparing the solid catalyst component and convert them into these compounds in the stage of the preparation.

(4) Preparation of solid titanium catalyst component (A) In preparing the solid titanium catalyst component (A), magnesium halide is preferably pretreated in advance. This preliminary treatment can be performed by various conventionally known methods, and specifically, the following methods can be exemplified.

(A) Grinding a magnesium dihalide or a magnesium dihalide and a halogen compound or a halogenated hydrocarbon compound of titanium, silicon or aluminum. Grinding can be performed using a ball mill or a rocking mill.

(B) A magnesium dihalide is dissolved using a hydrocarbon or a halogenated hydrocarbon as a solvent and an alcohol, a phosphoric acid ester or a titanium alkoxide as a dissolution promoter. Next, the dissolved magnesium dihalide is precipitated by adding a poor solvent, an inorganic halide, an electron-donating compound such as an ester or a polymer silicon compound such as methylhydrogenpolysiloxane to this solution.

(C) Contact reaction between magnesium mono- or dialcolate or magnesium carboxylate and a halogenating agent.

(D) Contact reaction between magnesium oxide and chlorine or AlCl ₃ .

(E) Catalytic reaction of MgX ₂ · nH ₂ O (X is a halogen) with a halogenating agent or TiCl ₄ .

(F) MgX ₂ · nROH (X is a halogen, R is an alkyl group)
And a halogenating agent or TiCl ₄ for contact reaction.

(G) A Grignard reagent, a MgR ₂ compound (R is an alkyl group), or a complex of a MgR ₂ compound and a trialkylaluminum compound is used as a halogenating agent, for example, AlX ₃ , AlR _m X
Contact reaction with _3-m (X is halogen, R is alkyl group), SiCl ₄ or HSiCl ₃ .

(H) The Grignard reagent is reacted with silanol or with polysiloxane, H ₂ O or silanol, and then with a halogenating agent or TiCl ₄ .

For details of such pretreatment of magnesium halide, see JP-B-46-611, JP-B-46-34092, and JP-B-51-351.
No. 4, No. 56-67311, No. 53-40632, No. 56-50888, No. 5
No. 7-48565, No. 52-36786, No. 58-449, JP-A-53-4568
No. 6, No. 50-126590, No. 54-31092, No. 55-135102,
No. 55-135103, No. 56-811, No. 56-11908, No. 57-1806
No. 12, No. 58-5309, No. 58-5310, and No. 58-5311 can be referred to.

The contact between the pretreated magnesium chloride, the titanium halide and the electron-donating compound can also be carried out by forming a complex of the titanium halide and the electron-donating compound and then contacting the complex with magnesium chloride. It is also possible to bring magnesium chloride into contact with a titanium halide and then to bring it into contact with an electron donating compound, or to bring magnesium chloride into contact with an electron donating compound and then to bring it into contact with titanium halide.

The contact method may be pulverization contact such as a ball mill or a vibration mill, or magnesium chloride or an electron donor-treated product of magnesium chloride may be added to the liquid phase of titanium halide.

Washing with an inert solvent may be performed after the three- or four-component contact or at an intermediate stage between each component contact.

Solid titanium catalyst component (A) thus produced
The titanium halide content is 1 to 20% by weight, the magnesium halide content is 50 to 98% by weight, and the molar ratio of the electron donor compound to the titanium halide is about 0.05 to 2.0.

Organoaluminum Compound (Component (B)) The organoaluminum compound used as the component (B) in the present invention has the general formula AlR _n X _3-n (where R is a carbon number 1).
To 12 hydrocarbon residues, X is a halogen or an alkoxy group, and n is 0 <n ≦ 3).

Such an organoaluminum compound is specifically,
For example, triethyl aluminum, tri-n-propyl aluminum, tri-n-butyl aluminum, triisobutyl aluminum, tri-n-hexyl aluminum, triisohexyl aluminum, trioctyl aluminum, diethyl aluminum hydride, diisobutyl aluminum hydride, diethyl aluminum Examples include monochloride, ethylaluminum sesquichloride, diethylaluminum monoethoxyside. Of course, two or more of these organoaluminum compounds can be used in combination.

The use ratio of the organoaluminum compound (B) and the solid titanium catalyst component (A) used in the polymerization of α-olefin can be varied within a wide range, but generally 1 to 1 per titanium atom contained in the solid catalyst component. The organoaluminum compound can be used in a ratio of 1000, preferably 10 to 500 (molar ratio).

Organosilicon Compound The organosilicon compound used in combination with the component (A) and the organoaluminum compound (which may be the same as or different from the component (B)) in the prepolymerization step of the present invention is an organosilicon compound represented by the following formula: It is a compound.

(Where R ¹ is a branched hydrocarbon residue, R ² and R ³
Is a branched or linear hydrocarbon residue, respectively, and n is 2 ≦ n
≦ 3).

R ¹ is preferably branched from a carbon atom adjacent to a silicon atom. In that case, the branching group is an alkyl group,
It is preferably a cycloalkyl group or an aryl group (for example, a phenyl group or a methyl-substituted phenyl group). More preferable R ¹ is ^one in which the carbon atom adjacent to the silicon atom, that is, the α-position carbon atom, is a secondary or tertiary carbon atom.

In particular, from the carbon atom bonded to the silicon atom 3
Those having a structure in which a number of alkyl groups are present are preferred. R ¹
Has a carbon number of usually 3 to 20, preferably 4 to 10.
R ² is usually a branched or linear aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. R ³ is an aliphatic hydrocarbon group, preferably 1 to 4 carbon atoms
Is usually a chain aliphatic hydrocarbon group.

The following are specific examples of organic silicon compounds represented by structural formulas.

The amount of the organosilicon compound used is usually 0.001 to 1 mol, preferably 0.01 to 0.5 mol, per 1 mol of the organoaluminum compound.

Electron-donating compound (optional component) Apart from the above-mentioned electron-donating compound used as a so-called "internal donor" in the component (A), the catalyst of the present invention, especially the catalyst for the present polymerization, is used as a so-called "external donor". As described above, the electron donating compound can be used as an optional component.

The electron-donating compound that can be used as the external donor may be any purposeful one, including those exemplified as the internal donor for the component (A). One specific example of such an electron-donating compound is an organosilicon compound, which is the same as or the same as the one used in the prepolymerization step of the present invention (details above) (the one represented by the above general formula). In addition to the compounds, diphenyldimethoxysilane, phenyltriethoxysilane and the like can be exemplified.

Production of Propylene Polymer The production method of the propylene polymer according to the present invention comprises two steps, a preliminary polymerization step of polymerizing 3-methyl-1-butene and a main polymerization step of homopolymerizing propylene.

Preliminary Polymerization Preliminary polymerization is a step of polymerizing 3-methyl-1-butene in an amount of 0.01 to 100 g per 1 g of the solid titanium catalyst component (A). In this step, preferably 0.1 to 50 g, more preferably 1 to 20 g, per 1 g of the solid titanium catalyst component (A).
-Methyl-1-butene is polymerized. If the amount of polymerization is less than 0.01 g per 1 g of the solid titanium catalyst, the effect of improving the rigidity of the product is insufficient, while if it exceeds 100 g, the catalytic activity decreases, which is not preferable.

The organoaluminum compound which forms the catalyst system in combination with the component (A) in the prepolymerization step may be the same as or different from the component (B) to be used in the main polymerization step, and specific examples thereof are It can be found in the examples of organoaluminum compounds used as component (B). The use ratio of the organoaluminum compound and the component (A) can be varied over a wide range, but generally, the ratio is 1 to 1000, preferably 10 to 500 (molar ratio) per titanium atom in the component (A). . It is clear from the above that the electron donating compound (other than the specific organosilicon compound which is an essential component) may be used in combination in the prepolymerization step.

This step is preferably performed in the presence of an inert solvent. As the inert solvent, known hydrocarbon solvents such as hexane and heptane can be used. The reaction temperature is 0-100
℃, preferably 20-80 ℃. The reaction pressure is
The pressure is preferably atmospheric pressure to 50 atm, more preferably atmospheric pressure to 10 atm.

This step can be carried out by any of a continuous method and a batch method, but it is preferable to carry out the method by a batch method for the same reason.

Main Polymerization The main polymerization is the catalyst component (A) subjected to the above-mentioned prepolymerization.
(And an organoaluminum compound and a specific organosilicon compound) are used to carry out homopolymerization of propylene in the presence of a polymer produced by prepolymerization. In the main polymerization step, it is usual to obtain a polymer of 95% or more of the total polymerization amount.

The catalyst in the main polymerization step is formed from the component (A) and the component (B), and the content thereof is as described above. It is also apparent from the above that the component (B) which is an organoaluminum compound may be used after being supplied to the prepolymerization step or may be newly supplied to the main polymerization step.

As the polymerization mode, slurry polymerization carried out in an inert solvent, liquid phase bulk polymerization carried out in a propylene solvent, gas phase polymerization carried out in a gaseous propylene atmosphere, etc. are used.

The polymerization pressure is normal pressure to 100 atm, preferably normal pressure to 40 atm, and the polymerization temperature is 30 to 90 ° C, preferably 50 to 80 atm.
° C.

This step can be preferably carried out by either a continuous method or a batch method.

In addition, hydrogen can be used as a molecular weight regulator.

The following examples further illustrate the present invention (the present invention is not limited thereto).

(Experimental example)

Example-1 Preparation of solid catalyst component A glass three-necked flask (with a thermometer and a stir bar) having an inner volume of 500 ml replaced with nitrogen was charged with 75 ml of purified heptane and 75 ml.
Of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride. Thereafter, the temperature of the flask is raised to 90 ° C., and the magnesium chloride is completely dissolved over 2 hours. Next, the flask is cooled to 40 ° C., and 15 ml of methylhydrogenpolysiloxane is added to precipitate a magnesium chloride-titanium tetrabutoxide complex. After washing with purified heptane, 8.7 ml of silicon tetrachloride and 2.0 g of phthaloyl chloride are added, and the mixture is kept at 50 ° C. for 2 hours. Thereafter, the resultant is washed with purified heptane, 25 ml of titanium tetrachloride is further added, and the mixture is kept at 25 ° C. for 2 hours. This was washed with purified heptane to obtain a solid catalyst component.

 The titanium content in the solid catalyst component was 2.7% by weight.

Prepolymerization Into a stirring autoclave with an internal volume of 1 liter, 500 ml of purified heptane, 8 g of the solid catalyst prepared above, 2 g of triethylaluminum and 0.5 g of tert-butylmethyldimethoxysilane were introduced, and further 40 g of 3-methyl-1-butene.
Was introduced and reacted at 50 ° C. for 3 hours. Then, washing was performed with purified heptane. The polymerization amount of 3-methyl-1-butene was 3.5 g per 1 g of the solid catalyst.

Main Polymerization A 3-liter stirred autoclave was sufficiently replaced with propylene, and then sufficiently dehydrated n-heptane 1.5.
Introduce liters and maintain at 75 ° C, then 7k with propylene
Pressurized to g / cm ² G. Further triethyl aluminum 0.3
8 g, diphenyldimethoxysilane 0.16 g and 30 mg of the above-prepared solid catalyst were introduced, and the gas phase hydrogen concentration was adjusted to 0.
Polymerization was carried out at 75 ° C. for 3 hours while adjusting to 15 vol%. Then propylene was purged and butanol was added.
Polymerization was stopped by adding 10 ml, and excess and drying were performed to obtain 383 g of polypropylene powder. The polymerization results and the quality evaluation results were as shown in Table 1.
The transparency of the film was also good.

In addition, each physical property in Table 1 was measured according to the following method.

NFR: ASTM-D-1238 Flexural modulus: ASTM-D-790 Comparative Example-1 Prepolymerization 1.5 liters of purified heptane in a stirring autoclave with an internal volume of 3 liters, 30 g of titanium trichloride manufactured by Marubeni Solvay, 90 g of diethyl ether. Aluminum chloride was introduced in a nitrogen atmosphere, 120 g of 3-methyl-1-butene was further introduced, and the mixture was reacted at 50 ° C. for 3 hours. Then, washing was performed with purified heptane. The amount of 3-methyl-1-butene polymerized is
It was 3.4 g per 1 g of titanium trichloride.

Main Polymerization A 3-liter stirred autoclave was sufficiently replaced with propylene, and then sufficiently dehydrated n-heptane 1.5.
1 liter was introduced, the temperature was kept at 65 ° C., and the pressure was further increased to 7 kg / cm ² G with propylene. Furthermore, 1.0 g of diethylaluminum chloride and 0.1 g of the solid catalyst which has been subjected to the prepolymerization step as titanium trichloride were introduced, and the hydrogen concentration in the gas phase was adjusted.
Polymerization was carried out at 65 ° C. for 3 hours while adjusting to 2.0 vol%. Then propylene was purged and butanol was added.
Polymerization was stopped by adding 10 ml, and over-drying was performed to obtain 317 g of polypropylene powder. The polymerization results and the quality evaluation results were as shown in Table 1.

Comparative Example-2 In the prepolymerization, the same experiment as in Example-1 was conducted except that tert-butylmethyldimethoxysilane was not added.

The results of polymerization and the results of quality evaluation are shown in Table 1.

Comparative Example-3 In the preliminary polymerization, the same experiment as in Example-1 was conducted except that tert-butylmethyldimethoxysilane was replaced with diphenyldimethoxysilane. The polymerization results and the quality evaluation results were as shown in Table 1.

Example-2 In this polymerization, the same experiment as in Example-1 was carried out except that diphenyldimethoxysilane was not added. The polymerization results and the quality evaluation results were as shown in Table 1. The transparency of the film was also good.

Example-3 In the main polymerization, the same experiment as in Example-1 was conducted except that diphenyldimethoxysilane was replaced with tert-butylmethyldimethoxysilane. Polymerization results and quality results are shown in Table 1.

Comparative Example-4 The same experiment as in Example-3 was performed except that the monomer was changed from 3-methyl-1-butene to propylene and tert-butylmethyldimethoxysilane was changed to phenyltriethoxysilane in the prepolymerization. Polymerization results and quality results are shown in Table 1.

As is clear from Table-1, Comparative Example-4 is significantly inferior to Example-3 in product density and flexural modulus of the product.

In Comparative Example 4, the same prepolymerization donor and main polymerization donor as in Example 4 described in JP-A-62-18406 are used.

[Brief description of the drawings]

FIG. 1 is a flow chart for helping to understand the technical contents of the present invention regarding the Ziegler catalyst.

Claims (1)

(57) [Claims] 1. A solid titanium catalyst component (A) containing magnesium halide, tetravalent titanium halide and an electron-donating compound as essential components and a general formula AlR _n X _3-n (where R
Is a hydrocarbon residue having 1 to 12 carbon atoms, X is a halogen or an alkoxy group, and n is 0 <n ≦ 3. ) In the presence of a catalyst formed from an organoaluminum compound (B) represented by
The solid titanium catalyst component (A) comprises an organoaluminum compound and a general formula R ¹ R ² _3-n Si (OR ³ ) _n (wherein R ¹ is a branched hydrocarbon residue, R ² and R ³ are Each is a branched or linear hydrocarbon residue, and n is a number of 2 ≦ n ≦ 3.)
In the presence of the organosilicon compound represented by the formula, 3-methyl-1-butene was added in an amount of 0.1 per 1 g of the solid titanium catalyst component (A).
A method for producing a propylene polymer, which is characterized by undergoing a step of polymerizing from 01 to 100 g.