BG60622B1 - Catalyst for stereospecific polymerization of -olefins, method for its preparation and method for the polymerization of -olefins - Google Patents

Abstract

The catalyst provides polymerization of propylene with increased stereospecificity. It is based on a complex of titanium trichloride inactivated by contacting an organo alumina containing the reaction product of compound (a) selected from organoaluminum compounds and compound (b) selected from hydroaromatic compounds whose hydroxyl group is sterically hindered .

Description

(5¾ STEEL SPECIFICATION CATALYST 1 POLYMERIZATION OF α-ALMENS, METHOD FOR MU PREPARATION AND METHOD FOR POLYMERIZATION OF α-ALMENS

The present invention relates to a solid catalyst

for stereospecific polymerization of α-magnesium, a process for its preparation and a method for the polymerization of α-olefins in the presence of this catalyst.

Stereospecific polymerization of α-olefins is known, in particular propylene, with a dpEkElga catalyst system containing a solid constituent based on titanium trichloride and an activator composed of an organometallic compound such as aluminum alkyl chloride.

[1] described superactive, solid catalytic complexes based on ΤίΌΙθ with increased internal porosity, allowing the production of propylene polymers with very good stereospecificity.

Fsj describes a pre-activation treatment of

- 2 these overactive catalyst complexes that can btdat stored under ^hexane over a long time without losing its qualities · preactivator can btdat selected from organo compounds, and especially of the formula / I /, which refines their nature, between hidrokarbilhidrokarbil oksihalogenvdite of Aluminum · It is also common practice to use diethylaluminum chloride, ethylaluminium chloride, ethylaluminium and triethylaluminum dichloride ·

Unfortunately, the stereospecificity of these complexes is not sufficient under all polymerization conditions in which they can be placed to be used, and especially at relatively elevated temperatures, at which the polymerization of propylene gas is often carried out. In fact, when the polymerization is carried out at relatively low temperatures, a significant decrease in the catalytic performance is observed.

Attempts have been made to remedy this disadvantage by polymerizing propylene in the presence of catalytic systems withstanding the above-mentioned superactive solid catalytic complexes modified by the introduction into the polymerization medium of a third component, which is usually an electrode onion compound / base A large number of electrode donor compounds of different nature have already been proposed as a third component capable of enhancing the stereospecificity of these catalytic systems / see. for example [h] /. Among these large numbers of electrode donor compounds, some phenolic compounds and some hydroxyaromatic compounds are particularly useful in such Γψ Improvement of stereospecificity resulting from the introduction of similar electrode donor compounds into the polymerization

medium, is furthermore significant only at relatively elevated amounts of the electrodone compound (the weight of the electrode donor compound is generally at least equal to the weight of the solid catalytic complex present in the medium and often much higher). Undesirable secondary effects such as unacceptable decrease in catalytic performance and the appearance of parasitic staining of the resulting polymer were identified, without mentioning the complications caused by the need to purify the polymer from the third component.

The present invention is intended to provide a catalyst whose stereospecificity is greatly enhanced without the need for the introduction of a third component into the polymerization medium.

The present invention relates to solid catalysts based on a complex of titanium trichloride usable for stereospecific polymerization of ^α -olefins preactivated by contacting a pre-activator-organoaluminum which reacts with the product of the reaction of an organoaluminum compound (a) and a compound (a) (selected from hydroaromatic compounds whose hydroxyl group is ethereally hindered / blocked).

The titanium trichloride complex solids used as the precursors for the preparation of the solid pre-activated catalysts of the present invention can be prepared by any known method. It is generally preferred to use solids obtained by methods involving an initial reduction of titanium tetrachloride. This reduction can be carried out using hydrogen or metals such as magnesium, and preferably aluminum. The best results are obtained from solids obtained by the reduction of titanium tetrachloride with an organometallic reducer.

- 4 The same may be for example an organomagnesium reducer. However, the best results are obtained with organo-aluminum reducers / 1 /.

Usable organoaluminum reducers (1) are preferably compounds that contain at least one hydrocarbon radical bonded directly to the aluminum atom. Examples of compounds of this type are mono-, di- and trialkylaluminum, whose alkyl radicals contain from one to twelve radicals and preferably from 1 to 6 carbon atoms such as triethylaluminum, isoprenylaluminum, diisobutylaluminum hydride and ethoxy diethylaluminium. With the compounds of this type, the best results are obtained with dialkylaluminum chlorides and especially with diethylaluminum chloride.

In order to obtain the substances based on the titanium trichloride complex (hereinafter referred to as prodrugs) used for the preparation of preactivated catalysts according to the present invention

The aforementioned reduced substances are subjected to treatment with at least one complexing agent, which is typically selected from organic compounds containing 1 or more atoms or groups »having one or more free electron pairs capable of providing coordination with titanium or aluminum atoms contained in titanium or aluminum halide · Preferably, the complexing agent is selected from the group of aliphatic ethers and most often from those whose aliphatic radicals contain from 2 to 8 atoms in the carbon, preferably 4 to 6 carbon atoms · A typical example of an aliphatic ether giving very good results is diiso amyl ether ·

These complex-forming treatments aim to stabilize or enhance the productivity and / or stereospecificity of the catalysts and are well known and described in detail in the literature.

- 5 Thus, for the preparation of the by-product, treatment in the complexing medium may consist of grinding the reduced solid in the presence of the complexing agent. It may consist in the thermal treatment of the reduced substance in the presence of a complexing agent. It may also consist of extractive washes of the reduced substance in the presence of mixed solvents containing a liquid hydrocarbon compound and an auxiliary polar solvent, for example ether. Reduction of titanium tetrachloride may also be accomplished with an organoaluminum reducer (1) in the presence of a complexing agent, for example by adding to the titanium tetrachloride a hydrocarbon solution of the product of the reaction of the complexing agent with this reducer and thereby reducing the product thus obtained in the absence of a complexing agent or in the presence of a new amount of complexing agent identical or different to the previous one. The treatment can also be carried out with the aid of a complexing agent with an amount of the latter sufficient to form a homogeneous solid solution based on titanium trichloride and precipitate by heating the so dissolved substance.

For the preparation of the by-product, the processing by means of the complexing agent may be combined with or followed by activation treatment. These activation treatments are also well known and described in the literature. They are typically carried out using at least one agent selected from inorganic halogenated compounds, organic halogenated compounds, interhalogens and halogens. Among these agents may be cited:

- 6 ali

- as inorganic halogen compounds, metal halides and non-metals, such as titanium and silicon halides;

- as organic halogenated compounds, halogenated hydrocarbons such as halogenated alkanes and carbon tetrachlorides, for example;

- as interhalogen chloride compounds and iodine bromides, for example;

- as halogen - chlorine, bromine and iodine

Examples of agents that are very suitable for activation treatment are titanium rachloride, silicon tetrachloride, iodobutane, monochloroethane, hexachlsetran, chloromethylbenzene, carbon tetrachloride, iodide chloride. The best results were obtained with titanium tetrachloride ·

The physical form in which the complexing agents and the agents used for the eventual activation of slimming are not essential for the preparation of the prodrug. · These agents can be used in gaseous or liquid state, the latter in the more conventional state in which they are at normal temperature and pressure. Treatment with a complexing agent and optionally activation treatment can be carried out in the presence of an inert hydrocarbon solvent selected from the liquid, typically, among the hydrophilic hydrocarbons, cycloaliphatic and aromatic matte hydrocarbons, such catbalkans. and isoalkanes and benzene · The relative details of the complexation and activation conditions applied most commonly may be found in, and in the reference cited therein ·

At any time after receiving it, after the reduction stage

- 7 wounding or complexation, or a possible activation step, but preferably after the reduction step, the prodrug may be subjected to a treatment aimed at reducing the fragility of the constituent particles. This treatment, called 'prepolymerisation', consists in the application of the solid with a lower α-monoolefin, such as ethylene or better propylene, under polymerization conditions, in such a way that a solid containing typically between 5 and 500% by weight of prepolymerized α-monool is obtained Bin · This prepolymerization can be conveniently carried out in a solid suspension medium in an inert hydrocarbon diluent as defined above, and at a duration sufficient to obtain the desired amount of prepolymerized mono-olefin solid. according to this embodiment, it is less brittle and allows polymers of good morphology to be obtained, even when polymerized at relatively high temperatures.

To convert it to the solid preactivated catalyst described below, the prodrug may be applied as it is, τ · β · without being separated from the medium in which it was obtained, or preferably after separation and possibly washing with an inert hydrocarbon solvent as defined above ·

A preferred method for the preparation of solids based on a titanium trichloride complex, used as by-products for the preparation of pre-reactivated solid catalysts according to the present invention, is described in · This method involves the reduction of titanium tetrachloride in an organoaluminum / reducer medium which in this case is preferably dialkylaluminium chloride, the alkyl chain of which contains 2 to 6 carbon atoms under mild conditions.

- 8 After a possible thermal treatment of the thus obtained reduced solid, the latter is subjected to treatment in a complexing agent medium as defined above. Finally, the titanium tetrachloride medium is treated and the solid, based on the resulting titanium trichloride complex, is separated, optionally washed in an inert hydrocarbon solvent, noted above, preferably selected from the liquid aliphatic. hydrocarbons having 3 to 12 carbon atoms and which is also the diluent; which can be used in all stages of the preparation of the solid product.

The preferred preparation method, defined in the previous paragraph, results in titanium trichloride complex catalyst particles, which are also described in [13 * These particles are spherical and generally have a diameter between 5 and 100 microns and most often between 10 and 50 microns. They are composed of agglomerates of microparticles, which are also spherical and have a diameter of between 0.05 and 1 micron, most often between 0.1 and 0.3 microns, and which are vigorously prickly. As a result, the particles have a specific surface area p p higher than TbA / g and are most commonly between 100 and 250 m ^l / g and a total porosity greater than 0.15 cm / g, which is most often between 0.20 and

Q

0.35cm / h. The internal porosity of my particulates contributes, in particular, to the overall porosity of the particles as evidence of the increased value of the porous oblique corresponding to pores of less than 200A in diameter greater than 0.11 cm / g and in most cases between 0.16 and 0.31 cm / g.

Substances based on the titanium trichloride (prodrug) complex obtained according to the method described in [13, choosing the operating conditions, comply with the following formula:

^τί 01 ₃ · (Α1Ιΐ01 ₂ ) _χ . &,

- 9 Η is Ις, is an alkyl radical containing 2 to 6 carbon atoms, C is a complexing agent such as described above, x is any number less than 0.20 and y is any number greater than high of 0.009. and generally lower than 0.20.

As an embodiment of this method of preparation, the aforementioned, which consists in pre-polymerisation of the reduced substance after possible thermal treatment and before treatment in the complexing agent medium, may be cited. α-monoolefin (propylene) under polymerization conditions. This prepolymerization is carried out in a suspension medium of the reduced solid in an inert hydrocarbon solvent, as defined above, at about 20 to 80 ° C for usually one minute to 1 hour.

According to the invention, the product obtained as described above is contacted with an organoaluminum preactivator which claims the reaction product of an organoaluminum compound (a) and a compound (b) selected from the heteroxy aromatic compounds whose hydroxyl group is ethereally blocked.

The organoaluminum compound (a) is typically selected from compounds of the formula:

in which Rr represents hydrocarbon radicals identical or different, having from 1 to 18 carbon atoms selected from the radicals alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, alkoxy and aryloxy; X is halogen is a number such that Oxi AND £ 3 ·

In the above formula, preferably R is an alkyl radical, linear or branched having from 2 to 8 hydrocarbon atoms, X is preferably chlorine, 71 is preferably such that 1-4 N 3.

10B qualitatively as examples of compounds (a) may be cited trialkylaluminum compounds such as trimethyl, triethyl-, tri-U-propyl, tri-and-butyl-, tri-1-butyl-, tri-H- hexyl-, tri-hexyl-, tri-2-methylpentyl- and tri-p-octylaluminum; dialkylaluminum monohalides such as diethyl-, di-N-propyl- and i-monochlorides

di - ^ - butylaluminum, monofluorides, monobromides and monohydrides of ethylaluminum; alkyl and aluminum di- and sesquichaloids such as methyl and ethyl aluminum chlorides and ethyl and isobutyl aluminum dichlorides; alkoxy aluminum halides such as methoxy and isobutoxyaluminum dichlorides; alkoxyaluminium such as monoethoxydiethylaluminum, diethoxymonoethylaluminum and dixexanoximono-0> hexylaluminum

Very good results have been obtained with trialkylaluminum and dialkylaluminum chlorides in particular triethylaluminum and diethylaluminum monochloride.

The compound (b) is selected from hydroxy aromatic compounds whose hydroxyl group is etherically blocked. A hydroxyaromatic compound whose hydroxyl group is etherically blocked is understood to mean all hydroxy aromatic compounds which contain a secondary or tertiary alkyl radical in the two orthohydroxy radicals group.

The compound (b) is generally selected from hydroxyarylene mono- or polycyclic substituted as indicated above, in particular hydroxybenzenes, hydroxynaphthalenes, hydroxyatracenes and hydroxyphenantrenes, also substituted and whose aromatic nuclei may have other substituents.

Examples of compounds (b) may be cited-11 di-tertiary and di-secondary-alkylated monocyclic monophenols in the ortho position with the hydroxy group, such as 2,6-di-tert-butylphenol, 2,6-di -tert-butyl-4-methylphenol, 3,5-tert-butyl-4-hydroxy and hydroxybenzene, 2,6-di-tert-decyl-4-methoxy-phenol, 2,6-di-tert-bu

til-4-isopropylphenol, 2,6-di-cyclohexyl-4-methylphenol, 2,6-diisopropyl-4-methoxyphenol and 2,6-di-tert-butyl-4-sec-butylphenol;

- 3- (3R, 6R, 6-di-lret-butyl-N-hydroxyphenyl) propionic acid monoesters, such as 3- (3- (3 *, 5 *, -di-tert-butyl-4-hydroxyphenyl) propionate-methyl, ethyl "CR ° Dust, N-Butyl, N-Octyl" D ° decyl ^and

U-octadecyl;

- di-tert-alkylated at the ortho position with respect to the hydroxyl groups of polyphenols, such as 2,2-bis ^ 2,6 * di-tert-butyl-hydroxyphenyl-propane, bis ^ 3, 5-di-tert-butyl-4 -hydroxybenzyl) methane, 4,4 * methylene-bis ^ 2,6-di-tert-butyl) phenol, 2,2'-methylene-bis 4-ethyl- & tert-butyl phenol, 1,3,5-arimethyl- 2,4,6-bis ^ 3, 5-di-tert-butyl-4hydroxybenzyl ^ benzene and ®ris ^ 2,6-di-tert-hexyl-hydroxy-phenyl ^ benzene;

- polyesters of 3- ^ 3 *, ^5, -di-tert-butyl-4-hydroxyphenyl) propionic acid such as tetrakis-methylene-3- ^ ', ^5, -di-tert-butyl-4'hidr hydroxyphenyl-propionate ethane;

- di-tert-and di-sec-alkylated at the ortho position with respect to the hydroxyl group of polycyclic monophenols, such as 1,3-di-tert-butyl-2-hydroxyatracene, 1,3-di-tert-hexyl-2-hydroxyphenanthrene ,

2,8-di-tert-butyl-hydroxynaphthalene, 1,3-di-tert-hexyl-2-hydroxynaphthalene and 1,3-diisoamyl-2-hydroxynaphthalene.

Very good results have been obtained with di-tert-alkylated monocyclic monophenols, in particular 2,6-di-tert-butyl-4-methylphenol and the 3-, 3-, 5-di-tert-butyl-4 monoesters -hydroxyphenyl-propionic acid, in particular with fy-octadecyl 3- (3 ', 5'-di-tert

- 12 butyl-4-hydroxyphenylpropionate, the use of the latter conveying the excellent stereospecificity of the solid catalyst obtained with the aid.

The general conditions under which compound (a) is brought into contact with compound (b) are determinative insofar as they cause a chemical reaction between these compounds. It is usually operated in a liquid phase, for example by mixing the compound (b) and the compound (a) in the absence of a liquid solvent, the compound (a) being often liquid at normal temperature and pressure. It can also be operated in the presence of an inert hydrocarbon solvent as defined above.

The molar ratio in which compound (a) and (b) are mixed can vary widely. Typically, 50 to 0.1 moles of compound (a) per mole of compound (B) are administered; preferably the amount of compound (a) is between 15 and 0.5 mol per mole of compound (b); very good results were reported for the molar ratios of compound (a) / ktm compound (b) between 3 and 1.

Compounds (a) and (b) may be contacted at temperatures generally between 0 and 90 ° C, preferably at a temperature close to room temperature (25 ° C), and their mixture may be maintained at these temperatures. conditions sufficient time for them to react with each other, usually between 5 minutes and 5 hours. This reaction is most often accompanied by gas separation, which makes it possible to monitor its course.

The exact chemical structure of the reaction product of compound (e _t ) and (b) is not known for certain. However, it is practically certain that this product corresponds at least in part to the empirical formula:

- 5 / which has the meaning given above, contains the same (same) hydrocarbon / hydrocarbon / radical / and / as that / those / containing / and / or in the organoaluminum compound / a / ·

- OD (represents an alkoxy group derived from compound (b); -He is halogen;

-are a number such that 0 ^ -p ^ 3, preferably such that 0,1 ^ p ^ 2,5;

- is a number such that 0 ^^ X2, preferably such that 0.5 ^ 4.5;

- as an amount such that SK ^ p + ^ £ 3.

According to the invention, the organoaluminum pre-activator obtained as described above is contacted with the product.

The conditions under which the preactivator is contacted. and the byproduct is only relevant insofar as they lead at least in part to the fixation of the pre-inductor on the byproduct. · In this arrangement, this contact of languages can be accomplished by any of the known methods. · This contact, for example, can be accomplished by grinding the impregnated material liquid phase containing preactivator.

Most commonly, the inactivator is used in the form of a solution in an inert hydrocarbon solvent, optionally used for its preparation:

(1) reaction product of compound (a) with compound (b), possibly accompanied (2) by excess compound (a) or compound (b), introduced but not reacted.

In this case, it is preferable to administer the solution of the drug

- 14 pa containing ingredient (1) and optionally ingredient (2) in a suspension of a byproduct of the same hydrocarbon solvent. This suspension is usually maintained at a temperature between 0 ° C and the boiling temperature under normal conditions of the inert hydrocarbon solvent in which the preactivator has been dissolved, preferably between 20 and 40 ° C, for about 5 to about 120 minutes and for preferably between 15 and 90 minutes. The amounts of prodrug and preactivator used are what is the molar ratio between the total initial amount of compound (s) and the amount of TtCfg contained in the prodrug _? and is typically between 10 and 10, between 10 gfedpochitane ^her 1. Very good results were obtained when defined above molar ratio is between 0.05 and 0.5.

At the end of this preactivation step, the so-catalyzed catalyst is separated from the reactivation medium and washed to remove pre-activator residues that have not been fixed, preferably in an inert hydrocarbon solvent of the same nature as the one used to obtain of the prodrug and the preactivator solution.

The separated and washed preactivated catalyst may then be optionally dried. It may, for example, be dried until the residual liquid hydrocarbon solvent content is less than 1% by weight, preferably less than 0.5% by weight relative to the weight of the titanium ferric acid which contains according to the conditions described in [δ].

The preactivated catalyst thus obtained contains always a certain amount in front of an activator fixed on itself and which cannot be separated from it by purely physical methods of separation. This amount of preactivator is usually between 5 and 500 g / kg TtCfg,

- 15 present in the catalyst, preferably between 50 and 300 g / kg. Therefore, the preactivated catalyst according to the invention contains less Ήϋίθ per unit of weight than the substance used as a by-product for its preparation. · Ezreki that the preactivated catalyst typically contains at least 50% by weight TcOfg relative to the total weight, it rarely contains more than about 80% .

The external morphology of the pre-activated catalyst particles according to the invention is no different from that of the pre-product used to prepare them. So, when they are obtained by exiting spherical particles made up of an agglomerate of spherical porous microparticles, they have almost the same structure, size and shape as the starting particles. However, the preactivated catalyst particles are less porous, in other words they are no longer characterized by an increased specific surface area associated with the increased porous volume characterizing the byproduct particles.

Before being washed and eventually dried, the preactivated catalysts of the invention can be immediately contacted with an inert hydrocarbon solvent, such as those defined above, and which are also applicable as solvents for suspension polymerization. Preactivated catalysts according to the invention may also be subjected to pre-polymerization treatment as shown above with respect to the prodrug. They can be stored under hexane or in the dried state, preferably in the cold, for long periods without losing their properties.

In the polymerization, the preactivated catalyst according to the invention is used in conjunction with an activator selected from the organometallic metal compounds of the la, Ila, II and III groups of the periodic

- 16 system published in [9 ^ and preferably between compounds of formula:

wherein - R 6 is a hydrocarbon radical containing from 1 to 18 carbon atoms and preferably 1 to 12 carbon atoms selected from the radicals alkyl, aryl, arylalkyl, alkylaryl and cycloalkyl; the best results are obtained when R 6 is selected from alkyl radicals having 2 to G carbon atoms;

- Y is a halogen atom selected from chlorine, fluorine, bromine and iodine; the best results are obtained when Y is chlorine;

-7P is any integer such that 0zmi3 and, preferably, 1.5 * ηνά2.5, the best results are obtained when m = 2.

Diethyl aluminum chloride provides maximum activity and stereospecificity of the catalytic system.

The catalyst systems thus defined are applied to the polymerization of unsaturated olefins, the molecule of which contains from 2 to 18, preferably from 2 to 6, carbon atoms, such as ethylene, propylene, butene-1, pentene-1, methylbutene-1, hexene-1. 3- and 4-methylpenten-1 and vinylcyclohexene. In particular, they are of interest for the polymerization - stereospecific to propylene, butene-1 and 4methylpentene-1 in crystalline polymers markedly isotactic. They are also used in the copolymerization of these olefins with one another, as well as with diolefins having 4 to 18 carbon atoms. For

t.

preferably the diolefins are unpaired aliphatic diolefins, such as hecaadiene-1,4, unpaired monocyclic diolefins such as 4-vinylcyclohexene, alicyclic diolefins having an endocyclic bridge, such as dicyclopentadiene, methylene and ethylene, and ethylene - normylene

harnessed aliphatic diolefins such as butadiene or isoprene.

They are also applied to the preparation of copolymers called blocks, which are formed by starting from α-olefins and diolefins. These block copolymers consist of sequences of segments of variable length chain; each segment consists of one homopolymer of α-olefin or a statistical polymer containing α-olefin and at least one comonomer selected from. α-olefins and diolefins. ^α- olefins and diolefins are selected from the above.

Preactivated catalysts according to the invention are suitable for the preparation of propylene and copolymer homopolymers

ϊ

ί

limers containing at least 50% by weight of propylene and preferably 75% by weight of propylene.

The polymerization can be carried out. by any of the known methods: in solution or in suspension, in solvent or in an inert hydrocarbon diluent, such as those defined in connection with the preparation of the catalyst and which is preferably selected from butane, pentane, hexane, x eptane, cyclohexane, methylcyclohexane or mixtures thereof. The polymerization may also be carried out in the monomer or in some of the liquid and gaseous monomers. The use of preactivated catalysts according to the invention is very convenient for gas phase polymerization. In fact, when the occurrence of amorphous and resin by-products in this type of polymerization is undesirable and when the technology does not permit their removal, the use of catalytic systems with increased stereospecificity is of particular interest.

The polymerization temperature is chosen between 20 and 200 ° q and preferably between 50 and 90 ° C, the best results are obtained for copper 65 and 85 ° C · The pressure is usually selected between atmospheric and 50 atmospheres and preferably between 10 and 30 atmosphere. It goes without saying that this pressure is a function of the temperature used

The polymerization may be carried out in a continuous or continuous manner.

The preparation of co-dimers, called block, can also be accomplished by known methods. It is preferable to use a two-step process consisting in the polymerization of ^α- olefin, usually propylene, according to a method already described in homopolymerization. Then, the other α-olefin and / or diolefin, usually ethylene, is polymerized in the presence of the homopolymer chain still active. This second polymerization can be carried out after complete or partial separation of the monomer which has not reacted during the first step.

The organometallic compound and the preactivated catalyst may be introduced into the polymerization medium separately from each other. They may also be contacted at a temperature between 40 and 80 ° C and a duration dependent on this temperature and may be from 1 hour to several days before being introduced into the polymerization reactor.

The total amount of organometallic compound to be administered is not decisive; it is usually greater than ODmillimol per liter of diluent, liquid monomer or reactor volume, preferably greater than 0.5mmol per liter.

The amount of pre-reactivated catalyst depends exactly on the ₄ V ·· its content in Tt-Clg · It is usually chosen in such a way that the entrainment of the polymerization medium is higher than

0.01 mol per liter of diluent, liquid monomer or volume of ύ

the reactor and preferably more than 0.05 millimolan liter.

The ratio of the amounts of organometallic compound of the activated catalyst is not decisive. It is usually chosen in such a way that the fashion attitude is organometallic

and. I d

I

Mr

I *

and preferably between 1 and 15. The best results are obtained when the fashion ratio is between 2 and 12.

The molecular weight of the polymers obtained according to the process of the invention can be adjusted by adding one or more molecular weight regulators, such as hydrogen, diethyl zinc, alcohols, ethers, alkyl halides, to the polymerization medium.

The stereospecificity of the preactivated catalysts of the invention is higher than the catalytic complexes described in [1] when prepared by the latter. Furthermore, this stereospecificity remains unchanged for long periods, even when the preactivated catalysts are stored at relatively high temperatures. However, when used, it is no longer necessary to add a conventional third component to the polymerization medium to enhance stereospecificity such as ether or hyster. It is self-evident that such addition of a third component to the polymerization medium containing the preactivated catalyst according to the invention does not go beyond the latter; however, such an addition would ultimately only lead to an improvement in stereo-specificity that remains marginal.

During the homopolymerisation of propylene in the presence of preactivated catalysts according to the invention, the ratio of amorphous polypropylene, estimated by measuring the weight of the boiling heptane polypropylene ktm obtained in pro

X * ³

the polymerization rate in polypropylene is always lower than 3%. This property is attributed to the resulting solid polypropylene, even when the preactivated catalyst has been stored at high temperature (45 ° C) for weeks.

The following examples serve to illustrate the invention.

In these examples, the symbols used have the following meaning: Ι · Ι · = isotactic index of the polymer, estimated by the fraction of the latter, expressed in% in terms of the total amount. A ·.?

obtained polymer which is insoluble in boiling heptane · ζ G = modulus of twist of the polymer measured at 100 ° C and at a rotation angle of 60 °, with the sample temperature fixed at 70 ° C and the conditioning time per 5min * Ά / BS 2782 - part1 - £ 50A method; 150 458/1, method B; J) I / V 53447 and A5TMJ) 1043 /. This module is expressed in daH / cm2.

№1 = molten flow index, measured at 2.16 kg at 230 ° C and expressed in g / 10min. / AZT 1238 /.

Β5Ά = specific gravity (apparent) of the insoluble polymer fraction measured by compaction and expressed in g / l · a = catalytic activity expressed conventionally in grams of insoluble polymer in the polymerization medium obtained per hour and _. per gram of TfCl3 contained in the preactivated catalyst.

EXAMPLE I i

A - preparation of the prodrug / substance based on titanium trichloride complex /

In an 800 ml reactor equipped with a two-blade beep pulp, rotating at 400 rpm, 90 ml of dry hexane and BOML pure Τί, ΟΙ ^ were introduced into a nitrogen atmosphere. This solution of hexane-TtCl 2 was cooled to 0 / * 1 / ° C. After 4 hours, a solution of THMl of diethyl aluminum chloride (DEAH) in 190 ml of hexane was added as the temperature.

-21c maintained at 0 / + 1 / ° C.

After the addition of the DEAH-hexane solution, the reaction medium composed of a suspension of fine particles was stirred for 15 min at 1 / -1 / ° C, then transferred for 1 hour at about 25 ° C and maintained at this temperature 1 hour and then transferred for about 1 hour at 65 ° C. Stirring was maintained at 65 ° C for one hour.

The liquid phase is then separated from the solid and the solid is washed 7 times with 200 ml of dry hexane, turning the substance into a suspension with each wash.

The solid thus obtained is suspended in 456 ml of diluent (hexane) and 86 ml of diisoamyl ether (DIAE) are added to the suspension. The suspension is stirred for 1 hour at 50 ° C. Then the treated substance is separated from the liquid phase.

This substance was again converted into a suspension in 210 ml of hexane and 52 ml of T1CC was added; the suspension was stirred (150 rpm) at 70 ° C for 2 hours. The liquid phase was then separated by filtration and the substance was washed 14 times with 270 ml of hexane based on the titanium trichloride complex.

B- Preactivation

In a 800 ml reactor equipped with an agitator rotating at 150 rpm, 70 g of the substance was introduced based on the titanium trichloride complex (containing about 820 g of TiClg (kg) suspended in 280 ml of hexane. The reactor is slowly introduced (30 minutes) (120 ml of preactivator solution) (hereinafter referred to as preactivator A) into hexane, pre-prepared, mixing 80 g of D№ (compound a) _and 176.2 g of 3- (3 *, 5 ' - Discret-butyl-4-hydroxyphenyl) propionate - octadecyl, known as CIVacGaige's IRGANOX 1076 / compound (6U per liter hexane. The molar ratio of compounds

-22 (a) and (used for the preparation of the pre-activator is 2, and the molar ratio between pre-activator A and the substance based on the titanium trichloride complex / expressed by the moles of compound a, placed at the beginning of the mole the catalyst / is 0.2.

The pre-activator solution is introduced into the reactor only 15 min after completion of the gas separation, which is observed in the process of mixing compound (a) and compound (¢).

The suspension thus mixed with the pre-activator A was stirred for 1 hour at 30 ° C.

After decanting, the resulting preactivated catalyst was washed 5 times with 100 ml of dry hexane, each time the catalyst was suspended, then dried by purging with nitrogen in a fluidized bed for 2 hours at 70 ° C.

The catalyst thus obtained is contained per kg 641 g of TiClg, 12 g of aluminum, 31 g of DIAE and about 250 g of preactivator A.

B - Suspension polymerization of propylene in liquid monomer in the presence of preactivated catalyst.

In a 5 liter autoclave, pre-dried and with an atmosphere of dry nitrogen, enter under a nitrogen stream:

- 400 mg of DEAH (in the form of a solution in hexane 200g / l) commercialized by SHERING (the atomic ratio C1 / A1 was achieved to be 1.02 by the addition of ethyl dichloride);

-100 mg preactivated catalyst (the molar ratio between DEAH and Τΐ, ΟΙβ is about 8);

- hydrogen with partial pressure of 1 bar;

- 3 l of liquefied propylene.

The reactor was maintained at 65 ° C with stirring for 3 hours, then the excess propylene was degassed and the polypropylene formed was separated.

- «r ·

-23 (PP) or 643 g of dry polypropylene.

The catalytic activity of the preactivated catalyst a is 3340; productivity increases to 6430 g polypropylene / g preactivated catalyst ·

This polypropylene has the following characteristics:

I.I = 98D%

G = 673 daH / cm ^

ΙΦΙ = 3.16 g / 10 min

F5A = 510 g / L

Examples 1P to '5 P,

These examples are given as comparative examples.

Example 1P.

A catalyst was obtained on the basis of the titanium trichloride complex as described in Example 1 part A, without preactivation as described in Part B of the same example.

This catalyst, dried as described in Example 1, contains 811g TiClg, 2.8g aluminum and 61g DIAE ·

With the catalyst thus obtained, the polymerization was carried out under exactly the same conditions as those defined in example 1 part B. The 785 g of dry PP obtained in this experiment were separated.

The catalytic activity a is, moreover, 3.230, and the productivity is increased to 7850 g PP / g catalyst.

This polypropylene has the following characteristics:

I.I = 94.9%

G = 572aH / cm ^

W = 7, 3r / 10min

BSA = 490g / L

The significant differences between the heptane-insoluble fractions and the G modules of the polymers obtained under comparable conditions according to Examples 1 and 1P indicate increased stereospecificity

- 24 of a catalytic system comprising the preactivated catalyst of Example 1.

EXAMPLE 2P.

The titanium trichloride complex catalyst prepared as described in Example 1 part A is preactivated with a solution containing only compound (b). Partial dissolution of the catalyst is observed, which further turns into fine granules. The polymerization is carried out as in Example 1 part B, but with such a quantity of catalyst that it contains about 3 Mg T ₃ Cl ₃ ·

535 g of PP are obtained, which corresponds to the activity of only 2550. This polypropylene represents fine granules / grains / and its

PSA is only 100g / l, which excludes its possible use. EXAMPLE 2P.

Example 1 Parts A and B are reproduced with the sole exception that a suspension based on the titanium trichloride complex is added sequentially, first a solution of compound (a) in hexane and 15 minutes after the addition of the solution of the compound is added of compound (b) in hexane. The values of

the fashion ratios of the copper compounds (a) and (b) added separately, and between compound (a) and the amount of TtCl ₃ in the catalyst are 2 and 0.2, respectively. The amount of catalyst released contains 757g / kg

The polymerization carried out as described in Example 1 part B allows polypropylene to be obtained with catalytic activity of only 3090, which is in the form of non-recoverable pieces.

EXAMPLE 4P,

Example 3p is reproduced by changing the order of introduction of the solutions of the compounds (a) and Cb2). The same phenomenon as in trimmer 2P / m · is observed, which is partial dissolution of the catalyst.

The polymerization as described in Example 1 part B allows polypropylene to be obtained in the form of fine grains with a PSA of only 200 g / l and catalytic activity of only 3450, which excludes the possibility of being used.

EXAMPLE 5P.

The catalyst based on the titanium trichloride complex prepared as described in Example 1P / m.p. unpredacted /, is used for polymerization according to the conditions of Example 1 part B

with the sole exception that in the polymerization medium besides DEAH, catalyst, hydrogen and propylene, the product IRGANOX 1076 is introduced in such a quantity that the molar ratio between this product and the ΤίΟΙβ present in the catalyst is about 0.2 ·

Catalytic activity 3286 yields polypropylene having the following properties:

Ι.Ι. = 96.2%. G = 575 kH2 cm2

ΜΡΙ = 5.2g / 10min

P ^ A = 505g / L

EXAMPLE 2.

A preactivated catalyst is prepared as described in Example 1, Parts A and B, except that the product IRGANOX 1076 is replaced by 2,6-di-tert-butyl-4-methyl-phenol commercialized under the name IONOL CCS.

The catalyst thus obtained contains, per kilogram of 632 g of TfcCl ₃ , 14 g of aluminum, 3Og DIAE and one amount of the preactivator, which is charged at approximately $ 0 0 approximately · It is used for the polymerization under the conditions of Example 1, Part B ·

This experiment allows to obtain an active agent 3230, polypropylene having the following characteristics:

Ι.Ι. = 95.9% Mr = 653cN / cm ' MFI = 9g / 10min PSA = 500g / l ΓίΕίΗΕΡ 3.

Preactivated Catalyst as Angled? schimer 1, common A and B, is used for the polymerization of propylene suspended in hexane under the experimental conditions described below.

A 1 liter dry and purified hexane was introduced into a 5 liter stainless steel autoclave and repeatedly purged with nitrogen. Then 400mg of DEAH (in the form of a solution in hexane and a concentration of 200g / l) and a catalyst equivalent of about 51mg of TtClg were successively introduced. The fashion ratio of DEAH / T * C1 ₃ is about 10.

The autoclave is heated at 65 ° C and brought to atmospheric pressure by slow degassing. It then creates an absolute hydrogen pressure of 0.3 bar; the propylene was then introduced into the autoclave to reach a total pressure, taking into account the temperature of 11.9 bar. This pressure is kept constant throughout the polymerization by the introduction of propylene gas.

After 3 hours, the polymerization was terminated by separation of propylene.

The contents of the autoclave were poured onto a Buchner, rinsed three times with 0.5 l of hexane and dried under reduced pressure and 60 ° C. 251 g of polypropylene insoluble in hexane are recovered. 0.75 g of soluble polymer was found in the polymerization and washing hexanes, corresponding to 0.3%. The catalytic activity is 1643. Productivity reaches 3157 g PP / g preactivated catalyst.

The insoluble hexane polypropylene has the following

creation: I.I. = 98.2% Mr = 654 daN / cm = 2.9g / 10min B $ A = 503g / l EXAMPLE 6P.

This example is given as a comparative.

In the presence of a catalyst prepared as described in Example 3, but omitting the preactivation step and containing 735 g / kg TiCl2 ^ polymerizes as in Example 3. At activity a equal to 1719 polypropylene is obtained, of which 1% is soluble in hexane used in polymerisation and washing, the insoluble portion of which has the following characteristics *

I.I. = 95.7%

G = 591aH / cm ^

MFI = 9.5g / 10min

RSA = 479g / L

EXAMPLE 4.

A preactivated catalyst was obtained according to the general conditions set out in Example 1 parts A and B. However, after treatment of the catalyst suspension obtained after stirring for 2 hours at 65 ° C, this suspension was cooled to about 55 ° C and then 2 bar of propylene is introduced into the free space of the reactor. This introduction continued for a long enough time (about 45 minutes) to obtain 100g of polymerized propylene per kilogram catalyst. The prepolymerized suspension is then cooled to 40 ° C and the assembly is continued as described in Example 1 of Part A.

The resulting preactivated catalyst contains, per kilogram, 28 grams of 611 g of TiClg, 9 g of aluminum, 14 g of DPAE and one amount ... calculated at about 143 g of preactivator A ·

This preactivated catalyst is used for the polymerization of propylene, the experiment comprising one initial step that takes place in a liquefied monomer and a second step that takes place in the gas phase under the experimental conditions detailed below.

The 5l autoclave used according to Examples 1 and 3 was introduced under a nitrogen current:

- 800mgLEAH Fr.

- amount of catalyst equivalent to 100mg of TXClg.

The DEAH / TiClg molar ratio is about 10.

An absolute hydrogen pressure of 0.2 bar is realized in the autoclave.

After stirring, 2 liters of liquefied propylene are introduced and the autoclave is heated to 60 ° C. At this temperature, polymerization is carried out over ZOmin. The autoclave is then degassed to a pressure of 15 bar and at the same time heated to 70 ° C. An absolute hydrogen pressure of 1 bar is then carried out, then propylene is introduced into the autoclave until the total pressure is reached, ® having in mind the temperature, 28 bar. After three hours, the polymerization was stopped by degassing the propylene and the polypropylene formed was separated, being 1150 g of dry PP.

The catalytic activity a of the preactivated catalyst is 3286, and the productivity reaches 7027 g PP / g preactivated catalyst. This catalyst has the following characteristics:

, I.I. = 97.9%

G = 698 daN / cm ² # 1 = 3g / 10min ^{p &} = 520g / _L

- 29 EXAMPLE 7F.

This example is provided as a comparison ·

A preactivated catalyst was obtained according to Example 4 but omitting the preactivation step. This catalyst contains, in kilograms, 718g ΤίΟΙβ, 3.8g aluminum and 84g dnaE. · Used for polymerization under the conditions of Example 4, it allows the preparation, in activity. «3168, of polypropylene with the following properties:

I.I. = 96.4% Mr t = 620dN / cm ' №1 = W / 10min E $ A = 516g / l EXAMPLES 5 to 7.

Preactivated catalysts were obtained according to the conditions mentioned in Example 4, such as the molar ratio of the compounds (aj) and used to prepare the preactivator A / see. Example 1 Part B (Examples 5 and 6) is modified to become whatever is the molar ratio of the pre-activator A and the catalyst based on the titanium trichloride complex / expressed in moles of compound (a) inserted at the beginning of the TiClg mole contained in the catalyst (see example 1 and also example 7)

The resulting preactivated catalysts were used to polymerize propylene suspended in hecaan under the general conditions mentioned in Example 3.

The experimental conditions for the preparation of the catalysts and the results of the polymerization are presented in Table I.

- 30 TABLE. I

Example _______________________________________ 5 6 7

Preparation of preactivated catalysts

compound (a ~) compound (b) • mol / mol 50 10 10 compound (s) • mol / mol 1 1 0.2 Tfc ^ stdtrasch into the catalyst the content of Τ / Οΐθ in the preactivations catalyst / g / kg / 724 672 709

Polymerization results catalytic.activity / g PP / g ΤίτΟΙθ x hour / 2160 2160 2130 PP soluble in polymerization hexane / percentage of total polypropylene / _B1_. 0 ^ 8 __'1 ______ 1.1./% / 97.3 98,2 97,4 G / daH / cm ^ / 678 688 689 MFI / g / 10min / 7.1 5.0 7.7 PSA / g / l / 502 502 504

- 31 EXAMPLE 8.

A preactivated catalyst was prepared according to the description in Example 4, which was used for polymerization carried out under the conditions set out in part E of Example 1, except that the reactor was maintained at 75 ° C with stirring for 2 hours.

Under these conditions, the preactivated catalyst allows the preparation of polypropylene having the following properties at activity a 5010.

1.¾. = 98.1% Mr = 698 dN / cm2 №1 = 5.9g / 10min PSA = 510g / l EXAMPLE 9 and 10.

Pre-reactivated catalysts were prepared according to the conditions mentioned in Example 1, Parts A and B, except that triethylaluminum (TEAL) (Example 9) was used as the compound (a); ethylaluminum dichloride (EALX) (Example 10).

These preactivated catalysts were used for the polymerization of propylene in suspension of a liquid monomer under the general conditions mentioned in Example 1 part B.

The characteristics of the preactivated catalysts and the results of the polymerizations are presented in Table II.

EXAMPLE

10

Nature of the compound fD Used for the preparation of the preactivated catalyst

THEAL

EADH

TiClg content in preactivated

catalyst / g / kg / 648 713 Activity </ / g PP / g Τι £ 1β x hour / 3136 2875 PROPERTIES OF PP Ι.Ι. /% / 98.0 97.7 £ / daH / cm ^ / 645 667 MFI / g / 10min / 3.4 3.7 PSA / g / l / 504 490

Claims (25)

Claims A catalyst based on a titanium trichloride complex for stereospecific polymerization of α-olefins, which is preactivated by contacting an organoaluminum preactivator, characterized in that said preactivator contains the reaction product of compound (a) selected from organoaluminum compounds , and compound (b) selected from hydroxy aromatic compounds whose hydroxyl group is ethereally blocked. Catalyst according to claim 1, characterized in that compound (a) is selected from the compounds of formula A1RX, η 3 -n in which R represents hydrocarbon radicals, the same or different, containing from 1 to 18 carbon atoms; - X is halogen; - η is a number such that 0 <and <3. A catalyst according to claims 1 and 2, characterized in that compound (a) is trialkylaluminum and hal halide aluminum. A catalyst according to claim 1, wherein compound (b) is selected from mono- or polycyclic hydroxyarylene containing a secondary or tertiary alkyl radical at both ortho positions relative to the hydroxyl group. Catalyst according to claims 1 and 4, characterized in that compound (b) is selected from di-tert-alkylated monocyclic monophenols and 3- (3 ', 5'-di-tert-butyl-4-hydroxyphenyl monoesters) ) propionic acid. Catalyst according to claims 1 to 5, characterized in that the pre-activator is prepared by mixing compound (a) with compound (b) in a molar ratio between 50 and 0.1 moles of compound (a) per mole of compound (b). Catalyst according to claims 1 to 6, characterized in that the product of the reaction of compound (a) with compound (b) corresponds to the empirical formula RAl (OR ') X, _{in + <rt} p q 3- (p + q) in which: - R represents the same hydrocarbon radical (s) as that contained in compound (s); - OR 'represents an aryloxy group derived from compound (b); - X is a halogen optionally contained in compound (a); -are a number such that 0 <p <3; - q is a number such that 0 <q <2; - the sum (p + q) is such that 0 <(p + q) <3. A catalyst according to claims 1 to 7, characterized in that contacting the preactivator is carried out by introducing the preactivator into a suspension of the preactivation catalyst in an inert hydrocarbon solvent. The catalyst according to claims 1 to 8, characterized in that the pre-activator is contacted with the pre-reactivation catalyst in a molar ratio between the initial total amount of compound (a) and the titanium trichloride contained in the catalyst between 10 ' ² and 1 mol / mol. Catalyst according to claims 1 to 9, characterized in that it is separated from the preactivation medium and washed with an inert hydrocarbon solvent before it is used for polymerization. Catalyst according to claims 1 to 10, characterized in that it is preactivated by contacting the pre-activator with a solid by-product corresponding to the formula TiCl _3. (AlR "Cl _{2) x} .C _y in which R" is an alkyl radical containing from 2 to 6 carbon atoms, C is a complexing agent chosen from aliphatic ethers whose aliphatic radicals contain from 2 to 8 carbon atoms, x is any number less than 0.20 and y is any number greater than 0.09. Catalyst according to claim 11, characterized in that the solid by-product is in the form of spherical particles with a diameter of between 5 and 100 microns, made up of microparticle agglomerates also having a diameter between 0.05 and 1 micron and whose the porosity is such that the specific surface area of the solid pre-product is between 100 and 250 m ² / g and that the total internal porosity is between 0.15 and 0.35 cm ³ / g. A method for preparing a catalyst according to claim 1, characterized in that said pre-activator comprises the reaction product of compound (a) selected from organoaluminum compounds and compound (b) selected from hydroxy aromatic compounds whose hydroxyl group is ethereal blocked. 14. The method of claim 13, wherein compound (a) is selected from compounds of formula A1RXp 3-n in which: - R represents the same or different hydrocarbon radicals containing from 1 to 18 carbon atoms; - X is halogen; - η is a number such that 0 <η <3. 15. The method of claim 13, wherein compound (b) is selected from mono- or polycyclic hydroxyarylene containing a secondary or tertiary alkyl radical at the two ortho-positions relative to the hydroxyl group. A method according to claims 13 to 15, characterized in that the pre-activator is obtained by contacting compound (a) and compound (b) at a molar ratio between 50 and 0.1 moles of compound (a) per mole of compound (b). A method according to claims 13 to 16, characterized in that the pre-activator is contacted with the solid prodrug in a molar ratio between the total initial amount of compound (a) and the amount of titanium trichloride contained in the prodrug between 10 ' ² and 1 mol / mol. 18. The method according to claims 13 to 17, characterized in that the contacting of the byproduct and the pre-product is carried out by introducing the pre-product in a suspension of the product in an inert hydrocarbon solvent. A method according to claims 13 to 18, characterized in that the pre-product and the inductor are kept in contact at a temperature between 20 and 40 ° C for a duration of between 15 and 90 minutes. A method according to claims 13 to 19, characterized in that the solid pre-activated catalyst is separated from the pre-activation medium and washed with an inert hydrocarbon solvent before being used for polymerization. 21. Method for the polymerization of α-olefins in the presence of a catalytic system containing an organometallic compound of the metals of groups 1a, Pa, Pb, IIIb of the batch system, and a solid catalyst based on a titanium trichloride complex that has been preactivated by insertion in contact with an organoaluminum preactivator, characterized in that said preactivator contains a reaction product of compound (a) selected from organoaluminum compounds and compound (b) selected from hydroxy aromatic compounds whose hydroxyl lna group is sterically blocked. 22. A method according to claim 21 for the stereospecific polymerization of propylene. 23. The method of claim 21 for the stereospecific polymerization of propylene in suspension in an inert hydrocarbon solvent. A method according to claim 21 for the stereospecific polymerization of propylene into a liquid monomer. 25. The method of claim 21, applicable to stereospecific polymerization of propylene in the gas phase.