DE1959820C3 - Process for homo- or mixed polymerization of ethylene - Google Patents

Description

GC ₄ H ₉ )

Al-CH ₂ -CH-CH ₂ -

(IC ₄ H ₉ ) CH ₃

is used.

-CH ₂ -Al

(JC ₄ H ₉ )

Various supported catalysts are already known, which are composed of the following components put together:

an organometallic compound;
a compound of a transition metal from subgroups IV, V or Vl of the Periodic Table, which on the surface of
a solid support, consisting of a chemically bonded hydroxyl groups and / or oxygen atoms containing compound of a divalent metal or a polymer which has electron donor groups, is fixed.

The organometallic compounds used as activators for the preparation of these supported catalysts are generally among the organic compounds of the metals of main groups I. to IV of the Periodic Table and in particular from the aluminum trialkyls. Aluminum triethyl, Aluminum triisobutyl and, in general, aluminum

OC ₄ H ₉ )

OC ₄ H ₉ )

nium trialkyls have heretofore been used with success.

It has now been found that a very special activator which does not belong to the class of aluminum trialkyls heard leads to particularly favorable results.

The subject of the invention is the method characterized in the claim.

The main result that can be achieved by using this activator is manufacture of ethylene polymers which have higher molecular weights than the products under the same Conditions with the activators used so far and in particular with aluminum triethyl and aluminum triisobutyl (compare, for example, French patent specification 15 29 845), the catalytic Activity is increased or at least kept at the level of the known procedures.

The product which is suitable for the purpose according to the invention is the initial product of the reaction between isoprene and aluminum triisobutyl, which is characterized by a ratio P = 0.25 and which corresponds to the following formula:

(JC ₄ H ₉ )

AI-CH ₂ -CH-Ch ₂ -CH ₂ -AI

CH ₃

The amount of activator that must be used is not critical as long as the activator is in large excess compared to the transition metal compound present in the polymerization medium. That The atomic ratio Al / M, where M denotes the transition metal, should be above 2; preferably lies it between 5 and 100.

The activator as defined above is used along with catalytic complexes in which the transition element is chemically attached to a solid Carrier is bound.

The latter is preferably chosen from among the compounds of the divalent metals, the hydroxyl groups and / or have chemically bonded oxygen atoms, and among the polymers, the electron donor groups contain.

The compounds of the divalent metals are preferably selected from the hydroxychlorides, hydroxides, partially hydrolyzed halides and oxygen compounds of these metals. Magnesium, calcium, zinc, tin, manganese, iron, cobalt or nickel are preferably chosen as the divalent metal. Mei-GC ₄ H ₉ )

As a reactive carrier, a magnesium compound and in particular an oxygen compound are preferred of this metal.

As polymers that have functional groups that can fix the transition element, e.g. B. by complexation, copolymers of vinyl alcohol with a content of 1 are particularly suitable up to 20 mole percent vinyl alcohol in the polymerized state in the molecule, hydroxylated polycondensates Formaldehyde and amine compounds; macromolecular compounds with carbon-carbon double bonds in the molecule; macromolecular nitrogen compounds that are practically free of hydroxyl groups are; macromolecular compounds with functional oxygen groups, but practically free of alcoholic Hydroxyl groups.

As halogen compounds of the transition metals which can be used for the preparation of the catalytic complexes it is expedient to choose one or more compounds from the group of halides and oxyhalides of the metals of subgroups IV, V and VI of the Periodic Table and in particular the chlorides

of titanium and vanadium, ζ. B. TiCl ₄ , VOCl ₃ and VCl ₄ -

The polymerization or interpolymerization of the olefins can be carried out by any known method be carried out, continuously or discontinuously, in gas phase, d. H. in the absence of a liquid Milieus, or in the presence of a dispersion medium in which the monomer is soluble as a liquid Dispersion medium can be used an inert hydrocarbon, which under the polymerization conditions is liquid, or the monomers themselves, which are in the liquid state below their saturation pressure being held.

The inventive method is suitable for the homopolymerization of ethylene and for the Copolymerization of ethylene with «-olefins, such as. B. propylene or butene-1.

In the case of the polymerization of ethylene and the copolymerization of ethylene with small amounts of other olefins, there is a particularly interesting application in the production of resins which at the same time have a low melt index, e.g. B. below 0.5, and have a large molecular weight distribution, the latter characterized z. B. by a factor Ca as defined in German Offenlegungsschrift 19 38 461, from above 5.

In addition, the activator used according to the invention is particularly suitable for use with Supported catalysts, as proposed in German Offenlegungsschrift 16 45 392 have been, which, in addition to the components already described, is an alkoxide of a metal of the subgroup IV of the Periodic Table and in particular a titanium alkoxide. One gets in this way in the presence of hydrogen very easily a polyethylene, which in addition to a low melt index and a broad molecular weight distribution, a reduced density and a particularly increased resistance against crack under tension.

The process according to the invention is also suitable for the production of rubber-like copolymers from ethylene and propylene and / or butene-1, as well as for the production of copolymers with diolefins, especially non-conjugated aliphatic diolefins, non-conjugated monocyclic dienes and non-conjugated acyclic dienes with an endocyclic bridge, provided that suitable Amounts of monomers are used. Suitable amounts are 50 to 99.5 mole percent of propylene or another Λ-olefin per 50 to 0.5 mol percent Ethylene. The amount of diolefin is generally between 0 and 20 mole percent.

In the production of rubber-like copolymers, the application of the invention permits Activator used to produce products that have an increased Mooney viscosity. It is known that the Mooney viscosity is one of the most common measures used to determine the plasticity of rubber, d. H. a deformability, is and gives an indication of its behavior during use, e.g. B. when kneading or extruding.

ίο It is known that, although the Mooney viscosity changes depending on the shape and configuration of rubber molecules as rubber is a non-Newtonian fluid, not a simple relationship between the Molecular weight and this level of viscosity (standard ASTM D 1646-67).

Needs oil for certain types of application and especially when stretching with significant amounts of oil one rubber compounds with a high Mooney viscosity. But now the majority of the procedures lead to Manufacture of ethylene-propylene copolymers and ethylene-propylene-diene terpolymers only for products with low or medium Mooney viscosity. One of the main advantages of the invention Procedure lies in the possibility of being very simple Wise and without loss of catalytic activity polyolefin elastomer with a high or even very high Mooney viscosity.

example

For the polymerization of ethylene, the reaction product of isoprene and aluminum triisobutyl is according to used in the table below:

This product is in an amount corresponding to an atomic ratio Al / Ti of 20, for the polymerization of ethylene, carried out in a 1.5-1 autoclave containing 0.5 l of hexane and 55 mg of a catalytic complex with a content of 22 g Contains titanium per kg. This catalytic complex is produced by reaction in the absence of a solvent of TiCl ₄ with a support based on magnesium oxide, obtained by calcining basic magnesium carbonate at 540 ^° C. for 16 hours under dry nitrogen.

Ethylene is then passed in ^{under a partial pressure of 10 kg / cm 2} and hydrogen under a partial pressure of 4 kg / cm ² .
The polymerization is carried out under constant pressure and with continuous introduction of ethylene for 1 hour at 85.degree.

Tabel

/ C5 / C4 lot Catalytic Catalytic Enamel Activator PÄ activity productivity index of the PA g- PÄ / h. G. G. PÄ / g. Ti. Atm. catal. G C ₂ H ₄ Solid g / 10 min Comparative experiment A 0 120 10,000 2200 0.32 example 0.25 143 11 800 2600 0.17 Comparative experiment B 0.9 129 10 750 2350 0.17 Comparative experiment C 1.4 132 11,000 2400 0.17 Comparative experiment D 1.9 115 9 600 2100 0.15 Comparative experiment E 2.6 94 7 830 1700 0.12 Comparison experiment F 3.3 77 6 420 1400 0.10

Claims (1)

Patent claims: Process for the polymerization of ethylene, alone or together with «r-olefins and / or diolefins, in the presence of catalysts from a solid complex, which is the reaction product of a halogen (IC ₄ H ₉ ) is derivative of a transition metal with a solid support, and an organoaluminum compound as an activator at an atomic ratio of aluminum to transition metal above 2, d a through characterized in that the activator is a compound of the formula