JPH02170802A - Preliminary polymerization of olefin - Google Patents

Abstract

PURPOSE:To obtain polyolefin of high crystallinity, high toughness and high heat resistance by conducting the preliminary polymerization of an olefin in multi-stages in the presence of a titanium compound. an organoaluminum compound, and a specific organosilicon compound wherein different organosilicon compounds are used in individual stages. CONSTITUTION:The preliminary polymerization of an olefin such as propylene is conducted in the presence of (A) a titanium compound, preferably titanium tetrachloride supported on magnesium chloride. (B) an organoaluminum compound, preferably triethylaluminum, and (C) organosilicon compounds of the formula (R, R' are hydrocarbons; n is 1 to 3) such as trimethylmethoxysilane, preferably at 0 to 60 deg.C in multi-stages and different organosilicon compounds are used in individual polymerization stages.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for prepolymerizing olefins. More specifically, the present invention relates to a prepolymerization method that makes it possible to obtain a highly stereoregular polymer in high yield when an olefin, particularly an α-olefin having 6 or more carbon atoms, is polymerized after the prepolymerization of the present invention.

(Problems to be Solved by the Prior Art and the Invention) Ziegler type catalysts are well known as olefin polymerization catalysts, and methods for improving their activity and stereoregularity have been proposed. Among these, significant improvement in activity has been achieved by using titanium, magnesium, and halogen as essential titanium components. However, when polymerizing propylene etc. using this catalyst,
It is also known that although the activity is very high, the stereoregularity of the resulting polymer is extremely low, so that its practical value is lost. So titanium and magnesium.

A method of improving stereoregularity by incorporating various electron donors such as esters, ethers, and amines into a halogen-containing titanium component has also been proposed. On the other hand, methods have also been proposed in which esters, ethers, amines, organosilicon compounds, etc. are added to the polymerization of such titanium components and organic aluminum. It is also known that by prepolymerizing with a small amount of propylene using such a catalyst system before the main polymerization, not only the polymerization activity and polymer particle properties are improved, but also the stereoregularity of the polymer is improved. (Japanese Unexamined Patent Publication No. 55-75409). However, although the stereoregularity of polymers has been considerably improved by these methods, it has not yet reached a satisfactory level, and in particular, various aspects such as high rigidity, high hardness, high heat resistance, and low heat shrinkage of molded products are not achieved. In order to satisfy the physical properties, even more highly crystalline polypropylene was desired.

(Means for Solving the Problem) As a result of intensive research aimed at obtaining a highly crystalline polyolefin, the present inventors discovered that the above object could be achieved by carrying out a specific prepolymerization, The present invention has now been completed.

That is, in the present invention, prepolymerization of an olefin is carried out in multiple stages in the presence of an organosilicon compound represented by the following components A, B, and CA, a titanium compound B, and an organic luminium compound C1 (general formula %). This is an olefin prepolymerization method characterized by using different organosilicon compounds in the polymerization step.

Titanium compound [A] used in the prepolymerization method of the present invention
Any compound known to be used in the polymerization of olefins may be employed without any restriction. In particular, titanium compounds with high catalytic activity containing titanium, magnesium, and halogen are suitable. Such titanium compounds with high catalytic activity are those in which titanium halide, particularly titanium tetrachloride, is supported on various magnesium compounds. Any known method can be used for producing this catalyst without any restriction.

For example, a method of co-milling titanium tetrachloride with a magnesium compound such as magnesium chloride, a method of co-milling a titanium halide and a magnesium compound in the presence of an electron donor such as an alcohol, ether, ester, ketone or aldehyde, Alternatively, there may be mentioned a method in which a titanium halide, a magnesium compound, and an electron donor are brought into contact with each other in a melting process.

Next, as the organoaluminum compound CB), any compound known to be used in the polymerization of olefins may be used without any restriction. For example, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-nibutylaluminum,
Tory n hexyl aluminum.

Trialkylaluminums such as tri-n-butylaluminum and tri-n-decylaluminum; diethylaluminum monohalites such as diethylaluminum monochloride; alkylaluminum-rides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, and ethylaluminum dichloride. Examples include. In addition, alkoxyaluminums such as monoethoxydiethylaluminum and jetoxymonoethylaluminum can be used. Among these, triethylaluminum is most preferred.

The amount of the organoaluminum compound used in each prepolymerization is 1 to 100, preferably 3 to 10, in terms of At, Ti (molar ratio) to the Ti atoms in the titanium compound.

Furthermore, the organosilicon compound CCI has the above general formula [1]
There are no restrictions on the compounds represented by (employed) general formula E
R and R' in ll are hydrocarbon groups such as an alkyl group, an alkenyl group, an alkynyl group, and an aryl group. Examples of organosilicon compounds preferably used in the present invention are as follows. For example, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyljethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane.

Diphenylshedkinsilane, ethyltrimethoxysilane, methyltrimethoxysilane.

Vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane.

Ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane, phenyltriethoxysilane, ethyl silicate.

These include 6-doryethoxysilyl 2-norbornene.

The amount of the organosilicon compound used in each prepolymerization step is 0.1 to 100, preferably 0.5 to 10, in terms of St/Ti (molar ratio), based on T1 atoms in the titanium compound. .

In the present invention, the above titanium compound [A], organoaluminum compound CB') and organosilicon compound [C
In addition to D, an iodine compound CDI represented by the following general formula [■]R"-1 [■] may be used.

This is preferable because the crystallinity of the polyolefin obtained is further increased.

In the general formula [■], R" is an alkyl group.

It is a hydrocarbon group such as an alkenyl group, an alkynyl group, or an aryl group. Specific examples of iodine compounds that can be suitably used in the present invention are as follows. For example, iodine, methyl iodide.

These include ethyl iodide, propyl iodide, butyl iodide, iodobenzene, and p-toluene iodide. Among them, methyl iodide and ethyl iodide are preferred. The amount of the iodine compound used in each prepolymerization step is I/Ti (mole ratio), based on the titanium atom in the titanium compound, from 0.1 to 100.
Preferably it is 0.5 to 50.

The most important feature of the present invention is that prepolymerization is carried out in multiple stages, and a different type of organosilicon compound is used in each prepolymerization stage. In the present invention, prepolymerization is performed in multiple stages.

Propylene is prepolymerized in the presence of each of the components [A], [B], [C) and CD) used as necessary, and the titanium-containing polyolefin obtained and the CF
! ], [refers to repeatedly carrying out prepolymerization of olefin in the presence of CD and each component [D] used as necessary.

Prepolymerization is preferably carried out 2 to 5 times. The above-mentioned components used in each prepolymerization may be added sequentially, or may be mixed together. The amount of olefin polymerized in each prepolymerization step is 0.00% per 1 g of titanium compound.
It is in the range of 1 to ioo, y, preferably 1 to 100 g, and industrially the range of 2 to 50.19 is suitable.

A different type of organosilicon compound is used in each prepolymerization step. As the organosilicon compound, it is preferable to use a compound in which R and R' in the general formula [1] shown in @ are a bulky hydrocarbon group, such as a bulky hydrocarbon group, such as a phenyl group, a cyclohexyl group, or a norbornyl group. This is preferred because a crystalline polyolefin can be obtained.The order of use of the organosilicon compounds used in each prepolymerization step is not particularly limited.

The olefins used in each prepolymerization include ethylene,
Examples include propylene, 1-phthene, 1-pentene, 1-hexene, and 4-methylpentene-1. Also,
It is possible to use two or more of the above-mentioned olefins at the same time, and different olefins can be optionally used in each prepolymerization step, but in consideration of improving stereoregularity, it is possible to use 90 mol% of a specific olefin. It is preferable to use the above.

It is also possible to coexist hydrogen at each stage of prepolymerization.

It is usually preferable to apply slurry polymerization to each prepolymerization, using a saturated aliphatic hydrocarbon or aromatic hydrocarbon such as hexane, heptane, cyclohexane, benzene, toluene alone or a mixed solvent thereof as a solvent. be able to. Each prepolymerization temperature is -20 to 100
"C1 A temperature of 0 to 60°C is particularly preferable, and each step of the prepolymerization may also be carried out under different temperature conditions. The prepolymerization time may be determined as appropriate depending on the prepolymerization temperature and the amount of polymerization in the prepolymerization. The pressure in prepolymerization is not limited, but in the case of slurry polymerization, it is generally from atmospheric pressure to about 5 to 4/-.Each prepolymerization is carried out in batches,
It is best to do it either in half batches or continuously. After each prepolymerization, hexane, heptane, cyclohexane,
It is preferable to wash the saturated JIW aliphatic hydrocarbon or aromatic hydrocarbon (benzene, toluene, etc.) alone or with a mixed solvent, and the number of washings is usually preferably 5 to 6 times.

The polymerization conditions in the polymerization after the prepolymerization according to the present invention are not particularly limited as long as the effects of the present invention are observed, but the following conditions are generally preferred. Polymerization temperature is 20-200℃
, preferably from 50 to 150°C, and hydrogen may also be present as a molecular weight regulator. Also.

Polymerization can be applied to slurry polymerization, solvent-free polymerization, and gas phase polymerization, and may be performed using batch, semi-batch, or continuous methods, and polymerization can also be performed in two or more stages with different conditions. can.

Ethylene is an example of olefins that undergo polymerization.

Propylene, butene-1, pentene-1. hexene-1
, 4-methylpentene-1, etc., and these monomers can be used alone or in a mixture of two or more. When using two or more types of olefins, it is preferable to use 90 mol % or more of one specific type from the viewpoint of improving the stereoregularity of the resulting polyolefin. Furthermore, ethers, amines, and amides are used to control the stereoregularity of olefins having 3 or more carbon atoms.

Electron rods such as sulfur-containing compounds, nitriles, carboxylic acids, acid amides, acid anhydrides, acid esters, and organosilicon compounds can be present. Among them, organosilicon compounds are preferred.

As such an organosilicon compound, one selected at the time of preliminary polymerization can be used.

(Effects) By employing the prepolymerization method of the present invention, a highly crystalline polyolefin can be obtained. For example, the polyolefin obtained can have a xylene soluble content of 1.0% or less. Furthermore, by the method of the present invention, a polyolefin can be obtained which not only has high crystallinity but also has excellent properties such as high rigidity, high heat resistance, high hardness, and low heat shrinkage.

(Examples) Hereinafter, the F1 present invention will be explained with reference to Examples and Comparative Examples.
The present invention is not limited to these examples.

The measurement method used in the following examples will be explained.

(1) Stereoregularity The stereoregularity evaluation method used in the present invention is as follows (a)
and (b).

(a) Add p-xylene soluble polyv-i11 to 100 cc of p-xylene, raise the temperature to 120°C while stirring, and continue stirring for an additional 30 minutes to completely dissolve the polymer. The xylene solution was left at 23° C. for 24 hours. The precipitate was separated by filtration, and the p-xylene solution was completely concentrated to obtain the soluble content.

Room temperature p-xylene soluble content (%)=(p-xylene soluble content (I)/polymer I II)X100.

(b) “C-NMR pentanode fraction Zambel
Macromolecules6.92 by li et al.
5 (1973), namely 1”
This is the fraction of isotactic bonding of five consecutive heptads in a polymer molecular chain using C-NMR.

The measurement was performed using JEOL G5X-270 with a pulse width of 90. Pulse Mli 15 seconds, ffrlj! It was performed 10,000 times. Peak assignment is Macromolecule
es, 8.697 (1975).

(2) Melt index (hereinafter abbreviated as 1MI) A
Compliant with STM D-790.

(3) Flexural modulus (hereinafter abbreviated as Fm) Japan Steel Works J
120SAII injection molding machine makes 63.6 x 12.
A test piece of 7 corals
790.

(4) Heat distortion temperature (hereinafter abbreviated as HDT) Japan Steel Works
65.6WX12. by J120SA ■ type injection molding machine.
A test piece of 7W x 0.31 m was prepared and ASTM:D
-648.

(5) Hardness (Rockwell hardness, R scale) 40 ttm x 40 m x 6 va by press molding machine
n test pieces were prepared and tested according to ASTM:D-785-5.

(6) Molecular weight distribution (hereinafter abbreviated as Mw/Mn) GP is the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn)
It was measured by C (gel permeation chromatography) method.

The test was carried out using nPc-150C manufactured by Waters Inc. at 135° C. using 0-dichlorobenzene as a solvent.

(7) Crystallization temperature (hereinafter abbreviated as Tc) Seiko Electronics Industry fir)
The temperature was maintained at -4°C/min and measured.

(8) Melting point (hereinafter abbreviated as Tm) By Seiko Denshi Kogyo DSC-200.

The sample was held at 230°C for 10 minutes, and the temperature was lowered to 120°C.
Isothermal crystallization was carried out at the same temperature for 10 minutes, and after cooling to 50°C, the temperature was raised at 10°C/min and measured l-.

Example 1 Preparation of titanium compound] The method for producing 1 liter of titanium component is described in JP-A-58-8300.
This was carried out according to the method of Example 1 of Publication No. 6. That is, 0.95 g (10 onmol) of anhydrous magnesium chloride, 10-1 decane and 4.7 2-ethylhexyl alcohol.
After heating and stirring =d (30 mmol) at 125°C for 2 hours, phthalic anhydride o, 5511 (3
, 75+nmol) was added thereto, and the mixture was further stirred and mixed at 125°C for 1 hour to obtain a homogeneous solution. Titanium tetrachloride held at 120°C after cooling in a room temperature cylinder
(0°36 mol) was added dropwise over 1 hour. After charging, the temperature of this mixed liquid was raised to 110°C over 2 hours, and when it reached 110°C, 0.54 td (2.5 mmo
1) was added thereto, and the mixture was then kept at the same temperature for 2 hours with stirring. After 2 hours of reaction, the solid part was collected by hot filtration.
This solid portion was resuspended in 200°C of TiCl2, and the reaction was again carried out by heating at 110"C for 2 hours.

After the reaction was completed, the solid portion was collected again by hot filtration and thoroughly washed with decane and hexane until no free titanium compound was detected in the washing liquid. The solid T1 catalyst component prepared by the above production method was stored as a heptane slurry. The composition of the solid T1 catalyst component is 2.1% by weight of titanium.
, chlorine 57%, magnesium 1s, offif%,
and diisobutyl phthalate 21.9% by weight.

[Prepolymerization]

Purified hebutane 200+a#, triethylaluminum 5Q mmo in a 1t autoclave with N2 substitution
l, diphenyldimethoxysilane 10mm0,1. 50mm01 of ethyl iodide and solid Ti catalyst component
After charging 5 mmol in terms of atoms, propylene was continuously introduced into the reactor for 1 hour in an amount of 5 g per 1 g of the solid T1 catalyst component to perform the first prepolymerization. Note that the temperature during this time was maintained at 15°C. After 1 hour, the introduction of propylene was stopped, and the inside of the reactor was sufficiently replaced with N2. The solid portion of the resulting slurry was washed six times with purified hebutane.

Further, this solid component was charged into a 1T-autoclave which had been replaced with N2, and 200v of purified hebutane and 50 mmol of ethylaluminum were added.

6-I + ethoxysilyl 2-norbornene 10m
After adding m o l + ethyl iodide 10i++nol.

Further, propylene is continuously introduced into the reactor for 1 hour to a ratio of 51 to 1 g of solid T1 catalyst component! -1 Prepolymerization was carried out for the second time. The temperature during this time was maintained at 15°C. The solid portion of the resulting slurry was washed six times with purified heptane to obtain titanium-containing polypropylene.

[Overlapping]

In an autoclave with an internal capacity of 400 tons that was subjected to N2 substitution,
Charged 200 tons of propylene, 274 mmol of triethyl aluminum, 274 mmol of diphenyldimethoxysilane.
mm o l + more.

Hydrogen 2. After charging ONt, the internal temperature of the autoclave was raised to 65 °C, 1.1 mmal of titanium-containing polypropylene was charged as titanium atoms, and then the internal temperature of the autoclave was raised to 75 °C [7,3 Polymerization of propylene was carried out for hours. The polymerization pressure was 34 to 9/-, the temperature during this time was maintained at 75°C, and the hydrogen concentration was maintained at 0.2 mo1%, although it was confirmed by gas chromatography. After 3 hours, unreacted propylene was purged to obtain a white granular polymer. The resulting polymer was then heated to 60°C with 200 tons of hebutane.

It was washed for 30 minutes and thoroughly dried. Total polymer yield +
15'l Kg, and the activity at this time is 208001
/ -pp/f1-cat-3hr.

An antioxidant was added to the above polymer, and the mixture was thoroughly mixed and formed into pellets using a granulator.

Md, D-xylene soluble content, 13C-NMR pentad fraction, Mw/Mn, Fm, HDT.

Table 1 shows the results of Tsukwell hardness, Tc, and Tm.

Example 2 In the prepolymerization of Example 1, the same operation as in Example 1 was performed except that ethyl iodide was not added during the prepolymerization. The results are shown in Table 1.

Example 6 To the titanium-containing polypropylene obtained in the prepolymerization of Example 1, 20Dd of heptane and 5) ethylaluminum were added.
0 mmol, phenyl 11 ethoxysilane 10 m
After adding 10 mmol of m○11 ethyl iodide, propylene was again introduced into the reactor for 1 hour in an amount of 5 g per 1 g of the solid T1 catalyst component to carry out the third prepolymerization. The obtained solid component was washed six times with purified hebutane.

Polymerization was carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 In the prepolymerization of Example 1, the same operation as in Example 1 was performed except that the second prepolymerization was not performed. The results are shown in Table 1.

Comparative Example 2 In the prepolymerization of Example 1, the second terror of prepolymerization
- instead of triethoxy nril 2-norbornene,
The same operation as in Example 1 was performed except that the same diphenyldimethoxysilane used in the first prepolymerization was used.

The results are shown in Table 1.

Examples 4 to 7 In the prepolymerization of Example 1, phenyltriethoxysilane, methyltriethoxysilane,
The same operation as in Example 1 was performed except that methylphenyltriethoxysilane and butyltriethoxysilane were used. The results are shown in Table 2.

Example 8 In the first prepolymerization of Example 1, 6-dryethoxysilyl-2- was used instead of diphenyldimethoxysilane.
The same operation as in Example 1 was performed except that diphenyldimethoxysilane was used instead of 6-dryethoxysilyl-2-norbornene in the second prepolymerization of norbornene. The results are shown in Table 2.

Example 9 The same operation as in Example 1 was performed except that in the prepolymerization of Example 1, the polymerization amounts of the first and second one-child polymerizations were carried out at the ratios shown in Table 3, respectively. The results are shown in Table 3.

Claims (2)

[Claims] (1) The following components A, B and C A, titanium compound B, organoaluminum compound C, general formula R_nSi(OR')_4_-_n [However, R and R' are the same or different hydrocarbon groups, n is an integer from 1 to 3. ] A method for prepolymerizing olefins, characterized in that prepolymerization of olefins is carried out in multiple stages in the presence of an organosilicon compound represented by the following, and a different organosilicon compound is used in each prepolymerization step. (2) The following components A, B, C and D A, titanium compound B, organoaluminum compound C, general formula R_nSi(OR')_4_-_n [However, R and R' are the same or different hydrocarbon groups. , and n is an integer from 1 to 5. ] Organosilicon compound D represented by the general formula R″-I “However, R″ is an iodine atom or a hydrocarbon group. ] A method for prepolymerizing olefins, characterized in that prepolymerization of olefins is carried out in multiple stages in the presence of an iodine compound represented by the following, and a different organosilicon compound is used in each prepolymerization step.