JPH06136072A - Production of propylene block copolymer - Google Patents

Abstract

PURPOSE:To obtain in high activity a rubbery propylene block copolymer high in molecular weight, with high rigidity and impact strength by two-step polymerization between propylene and an alpha-olefin using a specific carrying-type titanium catalytic system. CONSTITUTION:Using a catalytic system composed of (A) a solid catalytic component essentially comprising Mg, Ti, halogen and electron donor, (B) an organoaluminum compound (pref. trialkylaluminum) and (C) a piperidine compound (pref. 2,2,6,6-tetramethylpiperidine), propylene (and a small amount of another alpha-olefin) is polymerized and further polymerization is then made between propylene and the rest of the other alpha-olefin, thus obtaining the objective copolymer 2 600000 in the weight-average molecular weight of the 20 deg.C oylene solubles. The component A can pref. be prepared by the following process: aluminum trichloride is made to react with e.g. tetraethoxysilane followed by reaction with a Grignard reagent, and the resulting white solid is made to react with e.g. TiCl4 and an electrodonating o-phthalic diester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a propylene block copolymer having high rigidity and excellent impact strength.

[0002]

2. Description of the Related Art Crystalline polypropylene produced by using a Ziegler type catalyst has excellent properties such as rigidity and heat resistance, but it is especially used for automobiles, electric products, sports equipment and the like. In the above, the impact strength, especially the high impact strength at low temperature, is not always satisfactory, and improvement is desired. To improve impact strength,
A propylene block copolymer has been proposed in which a crystalline polypropylene is block-copolymerized with a rubbery copolymer of propylene and α-olefin.

As a method for producing a propylene block copolymer, in the presence of a Ziegler type catalyst comprising a combination of a supported titanium-containing solid and an organoaluminum compound,
A method of block-copolymerizing propylene and α-olefin by a slurry polymerization using an inert organic solvent, a gas phase polymerization, or a combination of a bulk polymerization and a gas phase polymerization has been proposed. In particular, in the production process by the combination of bulk polymerization in which a monomer in a liquid state is polymerized therein and gas phase polymerization in which the monomer is brought into contact with a catalyst in a gaseous state, isolation of a produced polymer and recovery of unreacted monomer are performed. It has the advantage of being easy.

Japanese Examined Patent Publication No. 55-7464 discloses a method in which bulk polymerization of propylene is carried out in the first step, and subsequently, gas phase polymerization of propylene with other α-olefin is carried out in the second step. A method of adding trialkylaluminum during the two-step polymerization to increase the polymerization activity is disclosed, but since the rubber-like copolymer component has a low molecular weight, moldability (spiral flow) during processing is deteriorated. at the same time,
There is a problem that the impact strength improving effect of the block copolymer is small.

In order to solve this problem, a method of using a catalyst comprising a supported titanium catalyst component and an alkylaluminum compound catalyst component, and further, as a third component, an organosilicon compound having a Si-OC bond or a Si-NC bond. (JP-A-61-69823), or unsaturated dicarboxylic acid diester (JP-A-63-284211), siloxanes or polysiloxanes (JP-A-63-69823) during the second-stage polymerization.
No. 146914), an asymmetric ketone compound (Japanese Patent Laid-Open No. 4-1360)
No. 10) is disclosed. However, it was not always satisfactory, and improvement was desired.

[0006]

It is an object of the present invention to produce a propylene block copolymer having a high copolymerization activity and a high molecular weight of a rubbery copolymer component of propylene and α-olefin using a supported titanium catalyst. To provide.

[0007]

The present invention is directed to the first step in which propylene or propylene and a small amount of other α-olefin are polymerized, and then in the second step, propylene and α other than propylene are mixed. -In a method for producing a propylene block copolymer for polymerization with an olefin, (A) magnesium, titanium, a halogen element and a solid catalyst component essentially containing an electron donor, (B) an organoaluminum compound, and (C) piperidine The present invention relates to a method for producing a propylene block copolymer having a weight average molecular weight of a 20 ° C xylene-soluble part of 600,000 or more, which is characterized by using a catalyst system comprising a compound.

In the present invention, a catalyst solid component containing magnesium, titanium, a halogen element and an electron donor as essential components is used as the component (A). The method for producing the catalyst solid component is not particularly limited, and includes, for example, JP-A-54-94590, JP-A-56-55405, JP-A-56-45909, and JP-A-56-16310.
No. 2, No. 57-63310, No. 57-115408,
58-83006, 58-83016, 58-138707, 59-149905, 60-23404, 60-328
The methods proposed in No. 05, No. 61-18330, No. 61-55104, No. 2-77413, No. 2-117905, etc. can be adopted. As a typical production method, a method of co-milling a magnesium compound such as magnesium chloride, an electron donor, and a titanium halide compound such as TiCl ₄ , a method of dissolving the magnesium compound and the electron donor in a solvent, and halogenating the solution. Examples thereof include a method of adding a titanium compound to precipitate a catalyst solid.

As the component (A), the solid catalyst components described in JP-A-60-152511, JP-A-61-31402 and JP-A-62-81405 are particularly preferable for achieving the effects of the present invention. preferable. According to the manufacturing method thereof described, wherein an aluminum halide (wherein, X ¹ is a chlorine atom, a bromine atom, or iodine atom.) Represented by AlX ¹ ₃ and, wherein R ¹ _n Si (OR ² )
_An organosilicon compound represented by _4-n (wherein R ¹ and R ² are
Each represents an alkyl group having 1 to 8 carbon atoms or a phenyl group, and n is an integer of 0 to 3. ) Were reacted to further wherein Grignard compound represented by R ³ MgX ² (wherein, R ³
Represents an alkyl group having 1 to 8 carbon atoms, and X ² represents a halogen atom. ) Is reacted to precipitate a solid. As the aluminum halide that can be used in the above reaction, anhydrous aluminum halide is preferable, but it is difficult to use completely anhydrous aluminum halide due to hygroscopicity, and aluminum halide containing a small amount of water should also be used. You can Specific examples of aluminum halides include aluminum trichloride, aluminum tribromide and aluminum triiodide, with aluminum trichloride being particularly preferred.

Specific examples of the organosilicon compound used in the above reaction include tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, methyltriethoxysilane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltributoxysilane, Examples thereof include dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trimethylmonoethoxysilane, and trimethylmonobutoxysilane. Particularly, tetraethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane and dimethyldiethoxysilane are preferable.

The amount of the compound used in the reaction between the aluminum halide and the organosilicon compound depends on the element ratio (Al / Si).
Is usually in the range of 0.4 to 1.5, preferably 0.7 to 1.3, and it is preferable to use an inert solvent such as hexane or toluene in the reaction. Reaction temperature is usually 10-100
℃, preferably 20 ~ 80 ℃, the reaction time is usually 0.2 ~
5 hours, preferably 0.5 to 3 hours.

Specific examples of the Grignard compound used in the above reaction include ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride, hexyl magnesium chloride, octyl magnesium chloride, ethyl magnesium bromide, propyl magnesium bromide, butyl magnesium bromide and ethyl. Examples include magnesium iodide. As the solvent of the Grignard compound, for example, an aliphatic ether such as diethyl ether, dibutyl ether, diisopropyl ether, diisoamyl ether, or an aliphatic cyclic ether such as tetrahydrofuran can be used.

The amount of the Grignard compound used is usually 0.5 to 3, preferably 1.5 to 2.3 in terms of the element ratio (Mg / Al) to the aluminum halide used in the preparation of the reaction product of the aluminum halide and the organosilicon compound. It is a range. The reaction temperature is usually -50 to 100 ° C, preferably-
20 to 50 ° C, reaction time is usually 0.2 to 5 hours, preferably
0.5 to 3 hours.

The white solid obtained in the reaction between the aluminum halide and the organosilicon compound and then the reaction with the Grignard compound is contact-treated with an electron donor and a titanium halide compound. Alternatively, the solid is contact-treated with an electron donor and then with a titanium halide compound. As the contact treatment, a conventionally well-known method can be adopted. For example, the above solid is dispersed in an inert solvent and the electron donor or / and the titanium halide compound is dissolved therein, or an electron donor or / and a liquid titanium halide compound is used without using an inert solvent. Disperse the solid in. In this case, the contact treatment between the solid and the electron donor or / and the titanium halide compound is stirred, and the temperature is usually
50 to 150 ℃, contact time is not particularly limited, but usually 0.2 to 5
Can be done in time. Further, this contact treatment can be performed multiple times.

Titanium halide compounds that can be used in the contact treatment include those represented by the formula Ti (OR) _p X _4-P (p is an integer of 0 to 3,
X represents a halogen atom. ). Specific examples include tetrachlorotitanium, tetrabromotitanium, trichloromonobutoxy titanium, tribromomonoethoxy titanium, trichloromonoisopropoxy titanium, dichlorodiethoxy titanium, dichlorodibutoxy titanium, monochlorotriethoxy titanium, monochlorotributoxy titanium. Can be mentioned. Particularly, tetrachlorotitanium and trichloromonobutoxytitanium are preferable.

The electron donor used in the above contact treatment is preferably an aromatic ester, of which orthophthalic acid diester is particularly preferable. Specific examples of the diester include diethyl orthophthalate, diisobutyl orthophthalate, dipentyl orthophthalate, dihexyl orthophthalate, di-2-ethylhexyl orthophthalate, and di-n-heptyl orthophthalate. After the above-mentioned catalytic treatment, the treated solid is generally separated from the treated mixture and thoroughly washed with an inert solvent, and the obtained solid can be used as the catalyst solid component (A) of the present invention.

As the organoaluminum compound as the component (B) in the present invention, trialkylaluminum and halogenoalkylaluminum can be used, but trialkylaluminum is preferred. Specific examples include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum and the like.

Any of the above organoaluminum compounds can be used as a mixture. Further, polyaluminoxane obtained by the reaction of alkylaluminum and water can be used as well. The amount of the organoaluminum compound as the component (B) used is 0.1 to 500 mol, particularly 0.5 to 150 mol, per 1 gram atom of titanium of the component (A).
Molar is preferred.

When the amount of the organic aluminum compound used is less than the above range, the copolymerization yield is not sufficiently increased, which is not preferable. On the other hand, if the amount exceeds the above range, the weight average molecular weight of the rubbery copolymer becomes small, which is not preferable.

Specific examples of the pyrridine compound which is the component (C) of the present invention include 2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetraethylpiperidine, 2,6-diisopropylpiperidine, 2,6-dibutylpiperidine, 2,2,5,5-tetramethylpiperidine, 2,5-diisopropylpiperidine and the like can be mentioned. Particularly, 2,2,6,6-tetramethylpiperidine is preferable.

The amount of the piperidine compound used is the amount of the component (B).
It is preferably 0.01 to 10 moles, and more preferably 0.05 to 1 mole per mole.

The first-stage polymerization may be either homopolymerization of propylene or copolymerization of propylene with a small amount of other α-olefin. Examples of the α-olefin include ethylene, butene-1, 4-methylpentene-1 and the like. The proportion of α-olefin other than propylene in the crystalline polymer obtained in the first step is preferably an amount that does not lose the properties of polypropylene, for example, 10% by weight or less. Α-other than propylene in the crystalline polymer
When the proportion of olefin exceeds 10% by weight, the low crystalline polymer by-product increases. If necessary, hydrogen may be added as a chain transfer agent in order to adjust the molecular weight of the produced polymer.

After producing a crystalline polymer in the first stage by homopolymerization of propylene or copolymerization of propylene with a small amount of other α-olefins, the catalyst system described above is not deactivated and Partially removing unreacted monomers in the polymerization, followed by addition of trialkylaluminum in the second step in the presence of the crystalline polymer without deactivating the catalyst system described above, A rubbery copolymer of propylene and an α-olefin other than propylene is produced.

The proportion of the rubber-like copolymer of propylene and the α-olefin other than propylene obtained in the second step is
It is usually 3 to 30% by weight, more preferably 5 to 15% by weight, based on the total amount of the block copolymer.

Α-other than propylene in the rubbery copolymer
The proportion of olefin is preferably 10 to 40% by weight. The molecular weight of the rubbery copolymer is 20% of that of the propylene block copolymer.
Evaluated by the weight average molecular weight of the xylene-soluble part. The 20 ° C. xylene-soluble portion of the propylene block copolymer obtained in the present invention has a weight average molecular weight of 600,000 or more, preferably 1,000,000 or more. When the weight-average molecular weight of the 20 ° C. xylene-soluble part is less than 600,000, the moldability (spiral flow) during processing deteriorates, and at the same time, the effect of improving the impact strength of the propylene block copolymer decreases.

As the polymerization mode of the present invention, slurry polymerization in an inert hydrocarbon solvent, bulk polymerization in which a monomer in a liquid state is polymerized therein as a solvent, gas phase polymerization in which a monomer is brought into contact with a catalyst in a gaseous state, Alternatively, these can be combined to carry out the polymerization.

The bulk polymerization is preferably carried out under conditions of temperature and pressure that can keep propylene or a mixed monomer of propylene and another α-olefin in a liquid state. The polymerization temperature is usually 30 to 90 ° C, preferably 50 to 80 ° C. The polymerization time is usually 5 minutes to 5 hours.

The slurry polymerization is carried out by introducing propylene or a mixed monomer of propylene and other α-olefin in the presence of an inert hydrocarbon. Examples of the inert hydrocarbon include n-pentane, isopentane, n-hexane, n-heptane, n-octane, isooctane, n-decane, benzene, toluene, xylene and cyclohexane. The polymerization pressure is usually from atmospheric pressure to 10 kg / cm ² ,
Preferably atmospheric pressure ~ 5kg / cm ² , the polymerization temperature is usually 30 ~ 90
℃, preferably 40-80 ℃. The polymerization time is usually 30 minutes to 10 hours, preferably 1 to 5 hours.

The gas phase polymerization is carried out under conditions of temperature and pressure at which a gas phase state can be maintained by introducing propylene or a mixed monomer of propylene and another α-olefin. α-
Examples of the olefin include ethylene, butene-1, 4-methylpentene-1 and the like. The polymerization pressure is usually atmospheric pressure to 10 kg / cm ² , preferably atmospheric pressure to 5 kg.
/ cm ² , the polymerization temperature is usually 50 ~ 95 ℃, preferably 65 ~
90 ° C. Polymerization time is usually 30 minutes to 10 hours, preferably
1 to 5 hours.

In the present invention, it is preferable to perform bulk polymerization in the first stage and slurry polymerization in the second stage. After the completion of polymerization, as a post-treatment step, the polymer solution slurry may be poured into a solvent such as ethanol, filtered and dried to obtain a polymer. Alternatively, the polymerization liquid slurry as it is,
A polymer can be obtained by filtering and drying. In the slurry polymerization, a low molecular weight product produced as a by-product can be removed in a post-treatment step, and the tackiness of the resulting block copolymer can be improved.

Further, in the present invention, it is preferable to carry out the main polymerization after prepolymerizing the olefin according to the above-mentioned various polymerization methods. The prepolymerization is, for example, usually -10 to 100.
The temperature can be 1 to 180 minutes at a temperature of 1 to 180 minutes under the condition that 1 to 100 g of the olefin polymer is obtained per 0.1 mg of the transition metal atom in the solid catalyst.

[0032]

According to the present invention, a propylene block copolymer having a high molecular weight of a rubbery copolymer component of propylene and α-olefin can be produced with high copolymerization activity.

[0033]

EXAMPLES Examples of the present invention will be described below. In the examples, the copolymerization yield is a polymer weight ratio in the second stage in the total polymer. The weight average molecular weight was determined by gel permeation chromatography (GPC). The measurement was performed using 150CV type GPC manufactured by Waters. (Solvent o-dichlorobenzene (containing 0.3% BHT), column SHODEX AT-80M × 2, temperature 145 ℃, sample concentration 0.03wt%, flow rate 1.0ml / min.) The ethylene content of the xylene soluble part was determined by IR. I asked. Creating a measurement sample
Place 0.5g of the sample between two ferro plates on a hot press hot plate with a thickness of 0.2mm and melt it for 1 minute at 180 ° C without applying pressure, and continue for 1kg at 50kg / cm ² G. After pressurizing for a minute, the film was rapidly cooled in a water tank. IR measurement is carried out using a Gardner calibration curve (IJGardner et.al., Rubber C
hem. & Tech. vol.44, 1051p. (1971)), 1155cm
^It was calculated from the intensity ratio of ^-1 and 720 cm ^-1 .

Example 1 (1) Preparation of solid catalyst component (A) 15 mmol of anhydrous aluminum chloride was added to 40 ml of toluene, and then 15 mmol of methyltriethoxysilane was added dropwise with stirring. The reaction was carried out for 1 hour. After cooling the reaction product to -5 ° C, 18 ml of diisopropyl ether containing 30 mmol of butylmagnesium chloride was added dropwise to the reaction product over 30 minutes with stirring, and the temperature of the reaction solution was adjusted to within the range of -5 to 0 ° C. I kept it. After the dropping was completed, the temperature was gradually raised and the reaction was continued at 30 ° C. for 1 hour. The precipitated solid was filtered off and washed with toluene and n-heptane. Next, 4.9 g of the obtained solid was suspended in 30 ml of toluene, and 150 mmol of titanium tetrachloride and 3.3 ml of di-n-heptyl phthalate were suspended in this suspension.
Mmol was added, and the mixture was reacted at 90 ° C. for 1 hour with stirring.
The solid was filtered off at the same temperature and washed with toluene and then n-heptane. Further, the solid is suspended again in 30 ml of toluene, 150 mmol of titanium tetrachloride is added, and the mixture is stirred at 90 ° C.
And reacted for 1 hour. The solid was filtered off at the same temperature, and the solid was washed with toluene and then n-heptane. The titanium content in the obtained catalyst solid component was 3.55% by weight. This solid was suspended in 80 ml of heptane to prepare a heptane slurry of catalyst solid components.

(2) Polymerization A glass ampoule containing a heptane slurry of a catalyst solid component (7.77 mg as a catalyst solid component) was attached to an autoclave with an internal volume of 2 L equipped with a stirrer, and then the autoclave was replaced with nitrogen. Then triethyl aluminum
2.057 ml of an n-heptane solution containing 2.057 mmol, and
0.343 mmol of 2,2,6,6-tetramethylpiperidine was charged to the autoclave. Then, after introducing 4.0 kg / cm ² G of hydrogen, 1200 ml of liquid propylene was introduced and the autoclave was shaken. The inside of the autoclave was cooled to 10 ° C., and when the stirring was started, the glass ampoule containing the solid catalyst component was crushed, and prepolymerization was performed for 10 minutes. Then, the inside of the autoclave was heated to 70 ° C. and the bulk polymerization in the first step was carried out for 20 minutes.

After the completion of the polymerization, unreacted propylene gas was released and the inside of the autoclave was replaced with nitrogen. The yield of homopolypropylene produced at this time was 193 g. Subsequently, 700 ml of heptane were injected under nitrogen. Then, the second stage slurry copolymerization was carried out at 65 ° C. for 120 minutes while feeding ethylene and propylene into the autoclave at atmospheric pressure and at a rate of 250 ml / min and 750 ml / min, respectively. After the polymerization was completed, the polymerized slurry was put into 1 L of ethanol to precipitate a polymer, and then 209.5 g of a copolymer was recovered by filtration and drying. Copolymer 5g to 500ml
After heat-dissolving in p-xylene and then leaving it at room temperature for 12 hours, the soluble part and the insoluble part were separated by centrifugation, the soluble part was put into 2 L of ethanol, precipitated, and collected by filtration and drying. The results are shown in Table 1.

Example 2 In Example 1, the amount of 2,2,6,6-piperidine used was 2.05.
Polymerization was performed in the same manner except that the amount was changed to 7 mmol. The results are shown in Table 1.
It was shown to.

Example 3 Polymerization was conducted in the same manner as in Example 1 except that triisobutylaluminum was used instead of triethylaluminum as the component (B). The results are shown in Table 1.

Example 4 Polymerization was carried out in the same manner as in Example 1 except that 2,2,6,6-piperidine was further added to 0.343 mmol in the second step.
The results are shown in Table 1.

Example 5 In Example 1, 0.343 mmol of 2,2,6,6-piperidine and 0.343 triethylaluminum were further added in the second step.
Polymerization was conducted in the same manner except that the amount was added in millimoles. The results are shown in Table 1.
It was shown to.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that cyclohexylmethyldimethoxysilane was added instead of 2,2,6,6-tetramethylpiperidine as the component (C). The results are shown in Table 1.

[0042]

[Table 1]

[Brief description of drawings]

FIG. 1 is a flow chart showing a polymerization method of the present invention and a step of preparing a catalyst solid component used in the polymerization.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichiro Yamada 8-1 Goi Minamikaigan, Ichihara City, Chiba Ube Industries Ltd. Chiba Research Institute

Claims (1)

[Claims] 1. A propylene block copolymer in which propylene or propylene is polymerized with a small amount of another α-olefin in the first stage, and subsequently, propylene is polymerized with an α-olefin other than propylene in the second stage. In the method for producing a polymer, (A) a solid component of a catalyst, which essentially contains magnesium, titanium, a halogen element and an electron donor,
A catalyst system comprising (B) an organoaluminum compound and (C) a piperidine compound is used, 20
C. A method for producing a propylene block copolymer, wherein the xylene-soluble part has a weight average molecular weight of 600,000 or more.