JPS5964602A - Polymerization of alpha-olefin - Google Patents

Abstract

PURPOSE:To obtain a polymer of a narrow MW distribution, by polymerizing an alpha-olefin with the aid of a catalyst comprising a specified supported titaminum catalyst component, an organo-aluminum compound, and a stereoregularity-improviding agent comprising an alkoxy gronp-containing silicon compound. CONSTITUTION:A supported titanium catalyst component comprising a compound comprising Mg, Ti, Cl and an organic compound containing at least a C-O bond is prepared by, for example, a method comprising copulverizing a magnesium halide with a C-O bond-containing organic compound, and treating the product by contact with a titanium halide. Then, an alpha-olefin (e.g., propylene) is polymerized by using a catalyst comprising a combination of the above supported titanium catalyst component, an organoaluminum compound (e.g., triethylaluminum) and a stereoregularity-improving agent comprising a silicon compound containing at least one alkoxy group (e.g., tetraethoxysilane).

Description

Detailed Description of the Invention The present invention produces poly-α-olefin with a narrow molecular weight distribution by polymerizing α-olefin using a catalyst consisting of a carrier-type titanium component, an organoaluminum compound, and a specific stereoregularity. Concerning a method of providing olefins.

Since the method of using a catalyst consisting of a supported transition metal catalyst, an organoaluminum compound, and a stereoregularity improver as a catalyst for the polymerization of α-olefins was proposed in Japanese Patent Publication No. 12105/1989, many improved methods have been proposed. has been achieved, and both the catalytic activity and stereoregularity have been significantly improved. However, in the prior art, a highly stereoregular polymer can be obtained in a high yield per catalyst by combining α-olefino with a catalyst system consisting of a supported transition metal catalyst, an organoaluminium compound, and a stereoregularity-enhancing agent. However, it is known that the obtained poly-α-olefin has a wide molecular weight distribution (Proceedings of the 1981 Annual Meeting of the Society of Polymer Science and Technology, vol. 131, pages 1000 to 1003, and P Shin+I, AI), a polymer.
5science A111) Ill Polym
crSympos i unsu6 113~132(1
981)). This feature of wide molecular weight distribution is preferable for injection molding and other products as it provides good flowability during molding, but for applications such as films and fibers, a narrow molecular weight distribution is required. Ap
p, Polymer 5science has been shown to narrow the distribution by thermal degradation.

However, thermal degradation not only requires expensive additives and extra energy, but also requires very strict control of each condition to produce products with consistent quality, which is complicated. There was a problem.

1. The present inventors conducted various studies on methods for narrowing the molecular weight distribution using the catalyst system described above, and as a result, by using specific additives, poly-α-
The present invention was completed by discovering that olefins can be obtained.

The present invention provides a method for polymerizing poly-α-olefin with a narrow molecular weight distribution using a catalyst consisting of a supported titanium catalyst component, an organoaluminum compound, and a stereoregularity improver. It is a complex consisting of Mg, i'i, OL and an organic compound containing at least a C-O bond, and is characterized by using a silicon compound containing at least one alkoke group as a stereoregularity improver. This is the way to do it.

An object of the present invention is to provide a poly-α-olefin with a narrow molecular weight distribution.

In the present invention, the supported titanium catalyst component is 17,'1
゛1. There is no particular limitation as long as it is a complex consisting of C and an organic compound containing at least a C-O bond, and any catalyst that provides a highly active and highly stereoregular poly-α-olefin may be used. Known catalysts are used, which are prepared by various methods.

For example, a composite obtained by co-pulverizing magnesium chloride, especially magnesium chloride, and an organic compound containing a C-0 bond, such as evaster, orthoester, alkoxy silicon compound, etc. Catalysts obtained by contact treatment with titanium chloride or liquid titanium trichloride or magnesium trichloride are made soluble in hydrocarbon solvents by mixing with alcohols and then with suitable precipitating agents such as silicon tetrachloride, tetrachloride, etc. After obtaining a precipitate insoluble in a hydrocarbon solvent with titanium chloride or an organoaluminum compound, contact treatment with a titanium halide, particularly titanium tetrachloride or liquid titanium trichloride (in this case, at the same time or before or after the treatment, a 0-0 (preferably treated with an organic compound containing a bond) or a catalyst obtained by rogenation of organomagnesium with a suitable rogenation agent. The complex can be treated with an organic compound containing an O-0 bond (although this treatment can be carried out at the same time as the treatment with the no-logogenating agent), and then by treatment with titanium tetrachloride or liquid titanium trichloride. The resulting catalyst is used. Of course, when obtaining a catalyst using each of the above methods, At20
3, S t 02, etc. or on other inorganic compounds, the above M2, C M'I
It is of course also possible to have a compound containing a ``i, Q-0 bond present.

In the present invention, examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, tripropylaluminum, triethylaluminum, a mixture of trihexylaluminum, diethylaluminum chloride, diglopylaluminum chloride, cyphythylaluminum chloride, cyhequinolaluminum chloride, etc. When used in the dialkylaluminum chloride dome synthesis, poly-α-olefins with high stereoregularity are often obtained.

In the present invention, as the stereoregularity improver, at least one
A silicon compound containing two alkoxy groups is used. The feature of the present invention is that a silicon compound containing an alkoxy group is used.The silicon compound containing an alkoxy group has the general formula (I(,"0)nsi-n (where ILl and R2 are an alkyl group, alkenyl group, aromatic hydrocarbon residue), such as tetraethoxydisilane, triethylethoxysilane, ethyltrinidoxinane, diethyljethoxysilane, teri-labroxysilane, propyltripropoxysilane, phenyltriethoxysilane, etc. Can be mentioned.

As the stereoregularity improver, other esters, especially esters of aromatic carboxylic acids, can be used in combination with the silicon compound containing the alkoxy group.

The usage ratio of each of the above components is 1 to 1000 mol of the organoaluminum compound and 0.5 to 50 mol of the stereoregularity improver per 1 atomic weight of Ti in the carrier-type titanium catalyst component.
Although it is generally used in an amount of 0 mol, it may be used in an appropriate ratio depending on the compound or carrier-type titanium catalyst component used.

In the present invention, a propylene polymerization reaction is carried out as the α-olefin.

There are no particular restrictions on the conditions for polymerization, and an appropriate range can be determined according to conventional methods, but the polymerization temperature is from room temperature to 100p, the pressure is from normal pressure to 50 kg/>n gauge, and hydrogen, etc. This is generally carried out using a molecular weight regulator. Also, the molecular weight distribution tends to be narrower when polymerized at a relatively high temperature, and if a narrow distribution is required, it is better to carry out the polymerization at a relatively high temperature.

EXAMPLES The present invention will be explained in more detail below with reference to Examples.

Examples 1 to 3 and Comparative Example 1 (N Synthesis of carrier-type titanium catalyst component) A vibratory mill equipped with two grinding pots each having an internal volume of 600 m containing 80 steel balls with a diameter of 12 is prepared. 13 ml was added to the pot in a nitrogen atmosphere and pulverized for 48 hours.The above pulverized product 402 was placed in a 1 ton round bottom flask, 300-ml of titanium tetrachloride was added, and the mixture was stirred at 80C for 2 hours.
Remove the upper surface liquid using a cantilever, then add 400 m of 11-hebutane, stir at room temperature for 15 minutes, and remove 10 kgl by decantation. After repeating the washing operation 7 times17.
When 400 ml of 1-hebutane was added and a part of the carrier-type titanium catalyst slurry was zumbling, n-hebutane was evaporated and analyzed, 1.9 wt% of T was found in the activated titanium component.
It contained 1.

(Polymerization of homogeneous propylene 5US-32 with an internal volume of 5 tons, thoroughly dried and purged with nitrogen
A catalyst slurry prepared by adding and mixing the above activated titanium component somy, the organoaluminum compound shown in the table, and a stereoregularity improver in 50 ml of 11-hebutane was charged into a prepared autoclave, and then 1.5 kg of propylene and hydrogen were added. The autoclave was heated with hot water to raise the internal temperature to 75C, and polymerization was carried out at 75C for 2 hours. After the polymerization is completed, unreacted propylene is discharged and white polypropylene is recycled to '4 fc.

The obtained polypropylene was dried under reduced pressure at 60℃, weighed, and the polymerization activity was calculated. - Calculated as xioo% (weight of hebutane extraction residue / weight of powder before extraction), hereinafter abbreviated as 1 and measured with a latralin solution with an intrinsic viscosity of 135C] and a trichlorobenzene solution at 145C Measure G PO and calculate M W / M
, N was calculated. The results are summarized in the table, and from this, in the system using alkoxy silicon, M w / M
It is clear that N is small and the distribution is narrow.

Example 4 and Comparative Example 2 (Synthesis of N carrier-type titanium catalyst component Mvct 29.7 y in a 200 m/! round bottom flask,
50 ml of kerosene, 46 ml of 2-ethylhexyl alcohol
．． 5m7! After stirring at 130C for 2 hours to dissolve the entire amount, 1.1 l of ethyl benzoate was added and the temperature was lowered. On the other hand, prepare a 1 ton round bottom flask containing 250 - 'l' i Ct4, and lower the temperature to -25[ while stirring.
Next, the above solution was added dropwise over a period of 1 hour, and after the completion of dropping -
20? After stirring for Z'-C for 1 hour, soak for 3 hours.
Raise the temperature to r, add 4.9me of ethyl benzoate, and add 5otr.
After further stirring for 2 hours, the mixture was allowed to stand and the supernatant was removed.
'i00me of C14 was added, stirred at 90C for 2 hours, left to stand, the supernatant was removed, and washed 7 times with 200me of 11-heptane in the same manner to obtain a catalyst slurry. (Titanium content: 1.2 wt%) Using this catalyst, polymerization was carried out in the same manner as in Example 1. The results are shown in the table.

14

Claims (2)

[Claims] (1) In the method of polymerizing polyα-olefin 7 having a narrow molecular weight distribution using a catalyst consisting of a carrier-type titanium catalyst component, an organoaluminum compound, and a stereoregularity improver, a) the carrier-type titanium catalyst component is M Y , '%i,C
It is a complex consisting of an organic compound containing at least one C-0 bond and a stereoregularity improver, and the use of a hydrogen compound containing at least one alkino group in L~. How to characterize it. (2) The method according to claim 1, wherein the polymerization reaction is carried out by bulk polymerization using propylene itself as a medium.