HRP920942A2 - Solid catalyst applicable for the stereospecific polymerization of alpha-olefines, process for their production and process for the polymerization of alpha-olefines in the presence thereof - Google Patents

Description

This invention relates to a solid catalyst applicable for stereospecific polymerization of α-olefin, a process for obtaining and a process for polymerization of α-olefin in the presence of this solid matter.

Stereospecific polymerization of α-olefins, such as propylene, is known using a catalytic system that includes a solid ingredient based on titanium trichloride and an activator that includes an organometallic compound, such as alkylaluminum chloride.

In the patent BE-A-780758 (SOLVAY & Cie), titanium trichloride complex particles are described, the use of which is particularly adapted in the polymerization of α-olefins. These particles are characterized by an extraordinary structure. They are actually composed of agglomerates of microparticles that are themselves extremely porous. This results in these particles possessing an increased specific surface area and corresponding porosity.

This particular structure gives exceptional polymerization performance. Due to the porosity of the microcapsules made mainly in pores of size below 200 Å, the catalytic activity is so elevated that they can be used in polymerization under such conditions that the catalytic residues do not need to be eliminated. Further, given that these particles have the shape of regular large spheres, the obtained polymer is also present in the form of regular spherical particles. This results in an increased specific mass and a very good fluidity.

However, these particles are not sufficiently suitable for the production of highly shock-resistant copolymer sequences (designated "high impact") obtained by incorporating, in the propylene homopolymer obtained in the first step, significant amounts of the propylene-ethylene elastomer obtained in the second step. Namely, the increased density and porosity, mostly limited in very small pores, of these particles of the titanium trichloride complex lead to homopolymers whose low porosity, in turn, does not allow the incorporation of increased amounts of elastomer, thus highlighting the problems of sticking, the more produced the greater the amount of elastomer that is incorporated. These problems are particularly troublesome in polymerization processes carried out according to the latest techniques, where the monomer is maintained in the liquid state or in the gas phase.

In an attempt to overcome these problems, these copolymers are produced in the presence of solid catalysts characterized by porosity below 0.08 cm3/g with pores in the range between 200 and 15000 Å (patent application EP-A-0202946 (SUMITOMO CHEMICAL). Preparation of the catalyst described in this application and which corresponds to this characteristic is, however, as complicated as the choice of operating mode to obtain a predetermined porosity.

It has now been found that solid catalysts of tunable porosity which can be used to obtain extensive gamma polymers of α-olefins can be obtained in a simple manner.

This invention relates, therefore, primarily to solid catalysts based on titanium trichloride complexes obtained by thermal treatment in the presence of an activating halogenated agent, a liquid substance that ensures the contacting of TiCl4, pretreated with an electrode donor compound, with compound (C) corresponding to the general formula :

AlRp (Y)q X3 - (p+q) (I)

where

R represents a hydrocarbon radical

Y represents a group selected from -OR', -SR' and -NR'R" in which R' and R" represent each hydrocarbon radical or hydrogen atom,

X represents halogen,

p is a number such that 0<p<3

q is a number such that 0<q<3, and the sum of (p+q) is 0<(p+q)≤3

In the formula (I) of the compound (C), R, R' and R" are, in the case where they represent a hydrocarbon radical, usually chosen independently of each other, among:

-alkyl radicals normal or branched, containing from 1-12 carbon atoms, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, n-hexyl, 2-ethylhexyl, n -octyl,

-alkenyl radicals containing 2-12 carbon atoms, e.g. ethenyl, 1-buenyl, 2-butenyl, 2-penten-4-yl, 1-octenyl, 1-decenyl,

-cycloalkyl radicals, possibly substituted, containing 5-12 carbon atoms, e.g. cyclopentyl, cyclohexyl, cyclooctyl radicals,

-aryl radicals, optionally substituted, containing 6-35 carbon atoms, for example phenyl, tolyl, cresyl, xylyl, naphthyl, 2,6-di-tert-butyl-4-methyl phenyl radicals,

-arylalkyl radicals containing 7-20 carbon atoms, eg benzyl radical.

In formula (I), p is preferably a number such that 1≤p≤2 and q is preferably a number such that 0.1≤q≤2 and most preferably 0.15≤q≤0.65.

Compounds (C) used to obtain solid catalysts according to the invention may be chemically defined compounds or may be mixtures of compounds. Formula (I) should therefore be considered as an overall structural formula that represents the mentioned compounds, or in the case of mixtures, it represents the average composition of the mentioned mixtures.

Compounds (C) used to obtain solid catalysts according to the invention can be obtained starting from organometallic compounds (A) of the general formula:

AlRnX3-n (II)

where R and X have the respective meanings given above in connection with formula (I) and where n is some number such that 0 n 3, preferably 1 ≤ n ≤ 3.

As examples of compounds (A), alkylated aluminum compounds can be cited, such as trialkylaluminiums, dialkylaluminum monohalides and di- and sexta-halides of alkyl aluminum whose alkyl radicals are defined above.

Compounds (A) are preferably dialkylaluminum chlorides, particularly diethylaluminum chloride.

To obtain compound (C), compound (A) can be contacted with compound (B) selected from compounds of the general formula:

AlRm(Y)m'X3-(m+M') (III)

YH (IV)

and between oligomers of the aluminoxane type present in cyclic forms and/or normal presented general formulas:

-/Al(R)-O/-n' + 2 (V)

and

R2Al-O-/al(R)-O/n' -AlR2 (VI)

In formulas (III), (V) and (VI) above, R, Y and X have the respective meanings given above in relation to formula (I). In formula (III) m is a number such that 0 m 3, preferably 0.5 m 1.5, m' is a number such that 0 m' 3, preferably 1 m' 2, the sum (m+m') is such that 0 (m+m') 3.

In formulas (V) and (VI), n' is a number usually between 2 and 50.

As examples of compounds (B) of the formula (III), we can cite tri- oxyaluminums, alkoxyaluminums, haloxyaluminum halides and alkylalkoxyaluminum halides. Preferred compounds (B) of the formula (III) are alkylalkoxyaluminums and their chlorides, especially diethylethoxyaluminum and ethylethoxy- and ethylisopentoxyaluminum monochlorides. Examples of compound (B) of formula (IV) include alcohols, thioalcohols, phenols, thiophenols and secondary amines. Preferred compounds of formula (IV) are aliphatic alcohols, eg methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, 2-methyl-1-pentanol (isoamyl alcohol), hexanol, 2-ethylhexanol, octanol. The most preferred alcohols are ethanol and isoamyl alcohol.

Examples of compounds (B) of formulas (V) and (VI) include methyl-, ethyl- and butylalumoxanes.

Compound (A) and compound (B) defined above are contacted in appropriate proportions to obtain compound (C) of formula (I) above. There is a reason for this taking into account the nature of the corresponding compounds (A) and (B) between which possible chemical reactions may take place during mixing.

The precise determination of the amounts of compound (A) and (B) upon contact is routinely tested beforehand.

A particularly desirable and simple operational method of obtaining compound (C) involves contacting compound (A) which is an alkylated aluminum compound with compound (B) which is an aliphatic alcohol at a ratio between the aluminum contained in compound (B) between 1/0.1 and 1/ 3. This contacting leads to at least a partial chemical reaction between these compounds, which leads mainly to the formation of the Al-OR' bond and the accompanying release of gases.

Other general conditions for obtaining compound (C) are not critical.

In general, it is done in the liquid phase, eg in a mixture between those compounds (A) and (B), at least one of which is often liquid under conditions of normal pressure and temperature. It can also be carried out in the presence of an inert hydrocarbon diluent, usually selected from aliphatic hydrocarbons, cycloaliphatic and aromatic liquids, such as liquid alkanes and isoalkanes and benzene. In this case, compound (C) is usually present in this diluent at 1-50% vol., preferably 5-30% vol.

Compound (A) and (B) may be contacted at temperatures between about 0 and 90ºC, preferably between about 20 and 50ºC, and their mixture maintained at that temperature for a time sufficient to eventually cause complete reaction between them, usually between 5 minutes and 48 hours, preferably between 2 and 24 hours.

To obtain solid catalysts according to the invention, compound (C) is contacted with TiCl4, which itself is pretreated with an electron donor compound. The electron-donor compound is generally selected from among organic compounds that include either several atoms or groups that possess one or more free electron pairs capable of coordinating with titanium. These compounds have 1-30 carbon atoms per electron donor atom or group.

Among the atoms suitable donors of one or more electron pairs, nonmetal atoms of groups V and VI of the periodic table can be cited, such as, for example, oxygen, sulfur, nitrogen, phosphorus, antimony and arsenic.

As representative examples of compounds containing groups suitable for donating one or more electron pairs, ethers, thioethers, thiols, phosphines, stibines, arsines, amines, amides, ketones and esters may be cited.

Preferably, the electron donor compound is selected from the family of aliphatic ethers, and more specifically from those whose aliphatic radicals comprise 2-8 carbon atoms, preferably 4-6 carbon atoms. A typical example of an aliphatic ether that gives very good results is diisoamyl ether.

The general conditions for treating TiCl4 with an electron-donating compound are not critical, as they cause complexation of TiVl4 with an electron-donating compound. In general, it is done in the liquid phase, by adding possibly an electron-donor compound, dissolved in an inert hydrocarbon as defined above, TiCl4 also in the form of a pure liquid or dissolved in such a diluent. As the diluent is used, TiCl4 is usually present in 1-50% vol., preferably 5-30% vol. Treatment of TiCl4 with the electron donor compound is carried out at a temperature usually between 0ºC and the boiling temperature of TiCl4 or possibly the diluent, preferably between 5 and 40ºC.

The molar ratio between TiCl4 and the electron donor compound can vary widely. It is usually between 0.01 and 20 moles of TiCl4 per mole of electron donor compound, preferably between 0.2 and 10 moles per mole. The best results are obtained with molar ratios between 0.3 and 5.

The general conditions of contacting TiCl4 pretreated with an electrode-donor compound as described above (called "pretreated TiCl4" for short) with compound (C) are no longer critical, because until the formation of liquid matter, it is mostly homogeneous and without solid substance. In general, compound (C) is introduced as a liquid pure or diluted in an inert hydrocarbon diluent, such as defined above, into pretreated TiCl4 which is itself in liquid form or diluted in an inert organic diluent inert or different from that in which it is possibly diluted compound (C).

Compound (C) and prereduced TiCl 4 are contacted in suitable amounts such as to produce at least partial reduction of TiCl 4 without substantial production of an accompanying solid precipitate. For this reason, the amount of the compound (C) contacted with the pretreated TiCl4 is such that the atomic ratio between the aluminum contained in the compound (C) and the titanium contained in the pretreated TiCl4 is usually between 0.05 and 10, preferably between 0.1 and 8, the best results are obtained for a ratio between 0.2 and 2.

The temperature at which compound (C) and the pretreated TiCl4 are contacted is usually between 0 and 60ºC, preferably between 10 and 40ºC.

To obtain the solid catalysts according to the invention, the liquid matter obtained as indicated above must be transformed into solid particles. For this, the material is subjected to heat treatment in the presence of a halogenated activating agent.

The general conditions of thermal treatment of liquid matter are not critical, since this treatment leads mainly to the deposition of solid particles based on titanium trichloride. These conditions are generally chosen to give particles of spherical appearance, granulometrically uniform and with an average diameter between 5 and 150 microns (mm), preferably between 10 and 100 mm.

For this, the liquid substance is progressively brought to a temperature above the contact temperature of the compound (C) with the pre-titrated TiCl4, which does not exceed the boiling point of the liquid substance.

In general, the temperatures between which the liquid matter is heated are around 20-150ºC, preferably around 40-130ºC, definitely 80-120ºC.

The duration of the thermal treatment is usually between 5 and 150 minutes, preferably between 20 and 120 minutes and definitely between 30 and 75 minutes.

Thermal treatment can be performed by raising the temperature of the liquid substance continuously or with several breaks during the temperature rise.

Other details relating to the thermal treatment of liquids, previously mentioned in defining these can be found mainly in patent US-A-4115533 (MITSUBISHI CHEMICAL INDUSTRIES) the contents of which are incorporated by reference into this description.

According to the invention, thermal treatment of liquid matter is performed in the presence of a halogenated activating agent. The term "halogenated activating agent" means all agents whose presence contributes to the transformation of solid reduced titanium trichloride that is undergoing heat treatment in liquid form mainly into the form of a violet stereospecific solid substance.

These agents are usually selected from inorganic halogenated compounds, organic halogenated compounds, hydrocarbyl aluminum halides, interhalogenated compounds and halogens. Among these agents can be cited:

As inorganic halogenated compounds, metal and non-metal halides, such as titanium, zirconium, aluminum, silicon and boron halides for example,

Halogenated organic compounds include halogenated hydrocarbons such as halogenated alkanes and carbon tetrachloride,

Alkyl aluminum dihalides whose alkyl radical contains 1-8 carbon atoms can be cited as hydrocarbyl aluminum halides.

Iodine chloride and bromide can be cited as interhalogen compounds.

Examples of halogens include chlorine, bromine and iodine.

Examples of very suitable activating agents are titanium tetrachloride, silicon tetrachloride, iodobutane, monochloroethane, hexachloroethane, chloromethylbenzene, carbon tetrachloride, ethylaluminum dichloride, iodine chloride and iodine. The best results are obtained with titanium tetrachloride (TiCl4).

The activator agent can be added to the liquid matter no matter at what point in the thermal treatment, for example it can be added at the beginning of the thermal treatment, it can also be added during the observed interruptions during the temperature rise, it can be added during the entire thermal treatment, especially during these interruptions.

When TiCl4 is used as an activating agent, this TiCl4 can conveniently originate from an excess of unreduced TiCl4, which is used to obtain the solid catalysts according to the invention.

The amount of activating agent used is expressed by the amount of titanium trichloride present in the liquid material. It is usually between 0.1 and 20 moles of activating agent per mole. The best results are obtained when the activating agent is used in an amount of 1-5 moles per mole of titanium trichloride.

It has been shown that it is convenient to subject solid particles based on the titanium trichloride complex to the thermal treatment of the liquid substance described above, aging usually carried out by a temperature shock at the end of the thermal treatment, the duration of which is usually between 15 minutes and 24 hours, preferably between 30 minutes and 5 hours.

Solid particles based on titanium trichloride, which is complexed and obtained according to the procedure described above, are preferably separated from their production environment, for example by filtering, decanting or centrifugation. Preferably, they are then washed using an inert hydrocarbon diluent of the same nature as that optionally used to obtain the solid catalyst.

As mentioned above, when the operating conditions of the thermal treatment of the liquid matter are adapted to this effect, these solid particles have a generally spherical shape, a narrow particle size distribution and an average diameter that is preferably between 10 and 100 mm. Their content of titanium trichloride is usually above 50% by weight, preferably above 75% by weight. and the content of the electron donor compound is usually below 15 wt.%, preferably below 10 wt.%, in relation to the total mass of the particles.

A significant advantage of the invention lies in the fact that the porosity of the solid catalyst particles can be regulated to a large extent by choosing certain operating conditions when obtaining them. It was also noted, in particular, with all other conditions remaining unchanged, that an increase in the content of Y groups in compound (C) leads to a modification of the porosity of the particles of the solid catalyst and, in particular, to an increase in the internal porosity of the particles formed by pores whose area is between 1000 and 15000 Å (called . here later simply VPI). Thanks to the production process of solid catalysts according to the invention, it is therefore possible to adjust their porosity from values as low as about 0.02 cm3/g to values as high as about 0.4 cm3/g.

It is equally noted that, with all other conditions remaining unchanged, increasing the amount of compound (C) with a significantly increased yield leads to obtaining solid catalyst particles of the smallest dimensions with very small pore volumes.

Increasing the porosity of the catalyst in the zone of the considered pore area mainly gives α-olefin polymers with increased porosity, which allows the incorporation of increased amounts and higher production of elastomers without the occurrence of sticking problems.

Various variants can be given to the methods of obtaining solid catalysts based on the titanium trichloride complex according to the invention, described above, without departing from the scope of this invention.

The first variant of embodiment (a) consists in adding, at some point, but preferably before the thermal treatment of the liquid matter, an organic carrier or an inorganic carrier (S) that represents a porous texture, so that the solid particles based on the titanium trichloride complex, they are separated on the surface of the carrier (S) or deposited inside its pores. This addition can be done, for example, before contacting TiCl4 pretreated with compound C.

For this, carriers (S) are used whose pore volume is at least equal to 0.1 cm3/g and preferably at least 0.2 cm3/g. This pore volume usually does not exceed 3.5 cm 3 /g, preferably does not exceed 2.5 cm 3 /g and most preferably does not exceed 2.2 cm 3 /g. Good results are obtained when the specific surface of the carrier (S) is above 1 m2/g. Most often, the specific surface of these carriers is below 900 m2/year.

Carriers (S) are usually composed of particles larger than 5 mm and most often above 10 mm. In general, the dimensions of the carrier particles (S) are not above 350 mm and preferably not larger than 200 mm.

Applicable organic carriers (S) are, for example, formed polymers such as polymers and copolymers of styrene, polymers and copolymers of vinyl chloride, polymers and copolymers of acrylic acid esters, polymers and copolymers of olefins containing 2-18 carbon atoms, etc. Polymers that are equally suitable for this application are polyacrylonitrile, polyvinylpyridine, polyvinylpyrrolidine.

Applicable inorganic carriers (S) are, for example, solid substances well known as catalytic carriers, such as oxides of silicon, aluminum, magnesium, titanium, zirconium and mixtures thereof. Among these inorganic carriers (S), solid substances based on alumina and silica, as well as their mixtures, are preferably used.

Applicable carriers (S) in this variant of the process according to the invention must generally be inert to the reagents used in the synthesis of solid catalysts based on the titanium trichloride complex, described above. For this, they can preferably be subjected, before their use, to a thermal treatment designed to eliminate all traces of residual moisture.

The solid catalysts thus obtained have an identical aspect to the supports used. Their porosity depends on the conditions of their production and the nature of the carrier (S) introduced into the medium for production.

The titanium trichloride content of the solid catalysts obtained according to this variant of the process according to the invention is usually between about 7 and about 60% and the content of the electron donor compound is usually between about 1 and about 10 wt.% in relation to the total mass of the solid catalyst.

This variant of the procedure for obtaining solid catalysts according to the invention constitutes another way of regulating porosity.

Another variant of embodiment (b) consists in a "prepolymerizer" of solid catalyst particles based on titanium trichloride complex, this "prepolymerization" treatment consists in contacting these particles with a lower α-monoolefin such as ethylene or better, propylene, under polymerization conditions to obtain a solid substance containing usually between 5 and 500 wt.% α monoolefin "prepolymerized". This prepolymerization can conveniently be performed on particles obtained from thermal treatment of liquid matter in a possibly inert diluent hydrocarbon, such as defined above for a time sufficient to obtain the desired amount of prepolymerized α-monoolefin on a solid substance.

The third variant of embodiment (c) consists in subjecting the solid catalyst particles based on the titanium trichloride complex to an additional activation treatment to maintain the stability of its properties and/or in order to increase its stereospecificity. This additional activation treatment consists in contacting the solid catalyst particles, preferably separated from the environment in which they were obtained, with an additional activation agent selected from organoaluminum compounds and the reaction product of the organoaluminum compound with a compound selected from hydroxyaromatic compounds whose hydroxyl group is sterically blocked. The organoaluminum compound is selected from trialkylaluminum and alkylaluminum chloride. The hydroxyaromatic compound is preferably selected from di-tert-alkylated monocyclic monophenols and 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionic acid monoesters, such as 3-(3',5'-di -tert-butyl-4'-hydroxyphenyl)propionate n-octadecyl.

It is also possible to combine the variants (b) and (c) described above, which means subjecting the solid catalyst particles to an additional activation treatment simultaneously with the "prepolymerization" described above.

Other details regarding the additional activation treatment defined above, mainly related to the nature of the organoaluminum compounds and hydroxyaromatics, are found together with the operative treatment conditions in patents BE-A-803875 (SOLVAY & Cie) and Fr-A-2604439 (Solvay & Cie ) whose content is incorporated by reference into this description.

For polymerization, the solid catalyst according to the invention is used together with an activator selected from organometallic compounds of metals of groups Ia, IIa, IIb and IIIb of the periodic table (version published in Kirk-Othmer Encyclopedia of Chemical Technologq, 2nd completely revised edition, vol.8, 1965 , p. 94) and preferably among compounds of the formula:

Al R'"xZ3-x

where R'" is

R'" is a hydrocarbon radical containing 1-18 carbon atoms and preferably 1-12 carbon atoms selected from alkyl, arylalkyl, alkylaryl and cycloalkyl radicals, the best results are obtained when R'" is selected from alkyl radicals containing 2-6 atoms carbon,

Z is a halogen selected from fluorine, chlorine, bromine and iodine, the best results are obtained when Z is chlorine,

x is some number such that 0 < x ≤ 3 and preferably such that 1.5 ≤ x ≤ 2.5, the best results are obtained when x is 2.

Diethylaluminum chloride (DEAC) ensures maximum activity and stereospecificity of the catalytic system.

A terconstituent commonly known to improve the stereospecificity of the catalytic system can equally be introduced into the polymerization medium between the solid catalyst and the activator defined above.

This terconstituent can be selected from, for example, ethers, esters, amides and organosilanes.

The catalytic systems defined in this way are used in the polymerization of olefins at the unsaturated end whose molecule contains 2-18 and preferably 2 carbon atoms, such as ethylene, propylene, butene-1, pentene-methylbutene-1, hexene, 3- and 4-methyl penethenes-1 and vinylcyclohexene. They are particularly interesting for the stereospecific polymerization of propylene, butene-1 and 4-methylpentene-1 into crystalline polymers that should be strongly or weakly isotactic. They are equally applicable in the copolymerization of these � olefins with comonomers selected from non-identical α-olefins and/or diolefins containing 4-18 carbon atoms. Preferably, the diolefins are unconjugated aliphatic diolefins such as hexadiene-1,4, monocyclic unconjugated diolefins such as 4-vinyl cyclohexane, endocyclic bridged alicyclic diolefins such as dicyclopentadiene, methylene- and ethylidene norbornene, and conjugated aliphatic diolefins such as butadiene or isoprene.

The advantage of catalytic systems according to the invention is that they allow, when their porosity is large enough, the incorporation of more significant comonomer fractions.

They are still used in the production of so-called copolymers. blocks that are composed of starting α-olefins and/or diolefins. These block copolymers form special blocks of variable composition. Each block consists of an α-olefin homopolymer or a copolymer statistically comprising one α-olefin and at least one comonomer selected from α-olefins and at least one comonomer selected from α-olefins and diolefins. α-olefins and diolefins are selected from those mentioned above.

The solid catalysts according to the invention are good for the production of propylene homopolymers and copolymers containing a total of at least 50 wt.% propylene and preferably 60 wt.% propylene. They are particularly suitable for the production of block copolymers composed of homopolymer blocks of crystalline propylene or statistical copolymer containing at least 90% and blocks of statistical copolymer containing 40-70 mol% propylene and 60-30 mol.% ethylene and is relatively abundant (more than 10 wt.% and up to 70 wt.% in relation to the total copolymer in the block) in these last blocks.

The polymerization can be carried out according to any known procedure: in solution or in suspension in a solvent or in an inert hydrocarbon diluent, such as is defined with respect to the solid catalyst and which is preferably chosen from butane, pentane, hexane, heptane, cyclohexane, methylcyclohexane or their mixtures. Polymerization can be carried out equally in the monomer or monomers maintained in the liquid state or still in the gas phase.

The use of more porous solid catalysts according to the invention is very suitable for the production of block copolymers rich in blocks of the statistical copolymer of propylene and ethylene defined above, especially in gas phase polymerization processes.

The catalytic systems according to the invention allow the incorporation of large amounts of statistical copolymer into the propylene homopolymer.

Or, this statistical copolymer is usually an amorphous product and sticky, which when present in the free state and in large quantities causes blocking and clogging of the polymerization reactor, which primarily occurs in gas phase processes. The use of catalytic systems according to the invention therefore has a special advantage.

The polymerization temperature is chosen mainly between 20 and 200ºC, and preferably between 50 and 90ºC, the best results are obtained between 65 and 85ºC. The pressure is chosen mainly between atmospheric and 50 atmospheres and preferably between 10 and 30 atmospheres. This pressure is of course a function of the temperature used.

Polymerization can be carried out continuously or intermittently. Obtaining copolymers of said blocks can be carried out equally according to known procedures. Preferably, a 2-step process is used which involves the polymerization of an α-olefin, usually propylene, according to the method described earlier for homopolymerization. Next, another α-olefin and/or diolefin, usually ethylene, is polymerized at the same catalytic site. This second polymerization can be carried out after the complete or partial removal of the unreacted monomer during the first stage.

The organometallic compound and the solid catalyst can be added separately to the polymerization medium. They can also be contacted, at a temperature between -40 and 80ºC, for a time that depends on this temperature and can last from 1 hour to several days, before being introduced into the polymerization reactor.

The total amount of organometallic compound contacted is not critical, usually above 0.1 mmol per liter of diluent, liquid monomer or reactor volume, preferably above 0.5 mmol per liter.

The amount of solid catalyst used is determined as a function of its TiCl3 content. It is usually chosen so that the concentration of the polymerization medium is above 0.01 mmol TiCl3 per liter of diluent, liquid monomer or reactor volume and preferably above 0.05 mmol per liter.

The ratio of the amounts of the organometallic compound and the solid catalyst is no longer critical. It is usually chosen in such a way that the molar ratio of the organometallic compound/TiCl3 present in the solid substance is between 0.5 and 20 and preferably between 1 and 15. The best results are obtained when the molar 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 to the polymerization medium several agents for adjusting the molecular weight such as hydrogen, diethylzinc, alcohols, ethers and alkyl halides.

The following examples serve to illustrate the invention.

The meaning of the symbols used in these examples, the units of expression of the mentioned quantities and the methods of measuring these quantities are explained below.

VPI = internal pore volume of the solid catalyst determined in the pore area zone between 1000 and 15000 Å and expressed in cm3/g.

Dm = average diameter of solid catalyst particles in mm.

VPF = total pore volume of solid polymer given in cm3/g.

VPS = total pore volume of the carrier (S) made in cm3/g.

Ss = specific surface area of solid catalyst made in m2/g (British Standard BS 4359/1).

Ssu = specific surface area (S) of the support made in m2/g (British Standard BS 4359/1).

α = catalytic activity produced usually in grams of polymer insoluble in the polymerization medium, obtained at a time per gram of TiCl3 contained in the solid catalyst. This activity was estimated indirectly by determining the amount of residual titanium in the polymer using fluorescence X.

PSA = specific mass of the expected insoluble polymer fraction made in g/dm3.

fTri = index of isotacticity of the polymer, determined by the mole fraction of the isotactic trinity (bonded sequence of three propylene monomer units in the meso configuration) in the total polymer. This value is determined using 13C nuclear magnetic resonance as described in Macromolecule vol.6, no. 6, p.925 (1973) and in references 3-9 of this publication.

MFI = fluidity index measured in solution at a batch of 2.16 kg at 230ºC and made in g/10 min (standard ASTM D 1238).

G = model of elasticity in torsion of the polymer, measured at 100ºC and for a torsion angle of 60º, the temperature of the mold was fixed at 70ºC and the duration of conditioning at 5 minutes (norms BS 2782-part I- method 150A. ISO 458/1, method B, DIN 53447 and ASTM D 1043). This model is expressed in N/cm2.

Et = ethyl radical C2H5.

Isoamyl = isoamyl radical (CH3)2CH-CH2-CH2-

The average particle diameter of the solid catalyst was evaluated by observation with an optical microscope of this solid substance in suspension in decalin (swelling 200).

The porosities of the catalysts and these resulting polymers in the polymerization tests described hereinbelow were measured by the mercury penetration method using commercially available Carlo Erba Co. porosimeters. in the pra area zone between 75 and 75000 Å.

The ethylene content of the block copolymers is obtained from the characteristic signals of these units observed by 13 C nuclear magnetic resonance as described by Rubber Chemistry and Technology, vol.44 (1971), p. 781 and following.

Examples 1-3

A Obtaining solid catalysts

1 Obtaining compound (C)

80 ml of a mixture of dry aliphatic hydrocarbons boiling at 175ºC (commercialized under the name Izopar H EXXON CHEMICALS) and 17 ml (136 mmol) of diethylaluminum are introduced into a 200 ml reactor equipped with a stirrer with a paddle rotating at 400 rpm, under a nitrogen atmosphere , chloride (DEAC).

The temperature of this solution is maintained below 50ºC, a selected amount of isoamyl alcohol, as given in Table I, below, is added dropwise. The solution is stirred for 20 hours at room temperature before use.

Compounds (C) can be represented by the general formula AlEtp(OIzoamyl)qCl, where the value of the numbers p and q corresponding to the molar ratios between the various constituents are given in Table I.

2. Synthesis of solid catalyst

100 ml of Isopar H and 15 ml of TiCl4 are introduced into a 1-liter autoclave equipped with a stirrer with a paddle rotating at 250 rpm, previously blown with nitrogen.

This solution is maintained at 30ºC and 69 ml (340 mmol) of diisoamyl ether (EDIA) is added over 30 minutes. After this addition, 97 ml of compound (C) as described in Table I with say 136 mmol of aluminum is introduced into TiCl 4 "pretreated" for half an hour. Finally, 45 ml of TiCl4 is added over about 10 minutes while raising the temperature to reach 100ºC after 1 hour. During thermal treatment, the first particles of a solid substance appear.

The reaction medium composed of the particle suspension is kept at this temperature for 2 hours (maturation) and then it is brought down to room temperature.

The liquid phase is then separated from the solid catalyst by decantation and the solid product (about 45 g) is washed in hexane by successive decantations, then dried for 2 hours under a stream of nitrogen at 70ºC.

The characteristics of these solid catalysts, purple in color, are also given in Table I below.

Particles of a solid substance are present in the form of spherical agglomerates of fine grains arranged in clusters.

B Polymerization of propylene in suspension in liquid monomer in the presence of solid catalysts (reference conditions)

It is introduced into a 5 liter autoclave, previously dried, under dry nitrogen.

400 mg of DEAC (in the form of a solution in hexane at 200 g/l) commercialized by the company SCHERING and whose atomic ratio Cl/Al was adjusted to 1.02 by the addition of ethyl aluminum dichloride,

50 mg of solid catalyst (the molar ratio between DEAC and TiCl3 present in the solid substance should be about 10),

hydrogen under a partial pressure of about 1 bar,

3 liters of liquid propylene.

The reactor is maintained with stirring at 65ºC for 3 hours. The excess propylene is then degassed and collected into polypropylene (PP), which is awarded in the form of grains with a regular morphology.

The results obtained during polymerization tests with different solid catalysts are also given in Table I below.

Table I

Examples 1 2 3

Obtaining compound (C)

volume of alcohol (ml) 3.75 7.5 9

empirical formula AlEtp (OIsoamyl)qCl

p 1.75 1.5 1.4

q 0.25 0.5 0.6

Characterization of solid catalysts

content of TiCl3 (g/kg) 805 773 770

aluminum content (g/kg) 1 1.2 1.3

EDIA content (g/kg) 95 78 62

CPI 0.043 0.06 0.08

Ss 172 174 90

Dm 15-20 10-20 15-25

Polymerization results

α activity 4810 3835 2200

PSA 366 378 318

fThree 91.8 91 93

G 605 515 -

MFI 17.2 2.9 25.1

VPF 0.06 0.1 0.17

Thus, it can be concluded that, with all other equivalent conditions, the variable contents of Y groups in compound (C) allow adjusting the internal porosity of solid catalysts to a considerable extent. More specifically, an increase in the intermediate pore volume for the pore area between 1000 and 15000 Å (VPI) is observed parallel to the increase in the content of Y groups.

Examples 4R and 5R

These 4R and 5R examples are provided for comparison.

Example 4R

100 ml of Isopar H and 15 ml (136 mmol) of TiCl4 are successively introduced into a dry autoclave of 1 liter, maintained at 30ºC with stirring (the mixer blade rotates at 250 rpm). Then 69 ml of diisoamyl ether (340 mmol) were added over 30 minutes. After this addition, while the temperature of the solution is progressively rising (1 hour) at 100ºC, 45 ml (408 mmol) of TiCl4 are added over 10 minutes. The reaction medium is maintained at this temperature for 2 hours, then cooled to room temperature, washed in hexane and dried in dry and warm nitrogen. This solid substance contains per kg: 635 g TiCl3, 12 g aluminum and 10 g EDIA, its VPI is 0.29 cm3/g and Ss is 140 m2/g.

The polymerization test is performed in the presence of this solid catalyst under conditions strictly identical to those described in example 1, part B. At the end of the test, 115 g of polymer (α=1280) present in the form of grains of irregular morphology, whose PSA is only 205 g/dm3, is collected .

Example 5R

A solid catalyst based on TiCl3 is obtained as described in example 1 but with compound (C) described below.

Compound (C) is obtained by mixing 80 ml of Isopar H, 8.5 ml (68 mmol) of DEAC and 22.75 ml (136 mmol) of dibutyl ether (EDBU).

The solid catalyst contains 799 g/kg TiCl3, 1.3 g aluminum and 86 g EDIA, its VPI is 0.26 cm3/g.

The polymerization experiment (conditions: example 1, part B) allows to obtain with activity α only 1190 polymers whose isotacticity index measured by NMR is only 86%.

Examples 6 and 7

Solid catalysts are obtained as in example 1 except that TiCl4 is added.

In example 6, the thermal treatment of the liquid obtained from the contacted pretreated TiCl4 and solution (C) is performed after the addition of the total TiCl4.

In Example 7, the total TiCl4, say 60 ml, is fed at once at the beginning of the synthesis of the solid catalyst.

The characteristics of this solid substance as well as the results of polymerization tests are given in Table II, below.

Table II

Examples 6 7

Properties of a solid catalyst

TiCl3 content (g/kg) 860,776

aluminum content (g/kg) 0.8 1.2

EDIA content (g/kg) 85 71

CPI 0.06 0.06

Ss 159 176

Polymerization results

α activity 3835 3700

PSA 376 375

fThree 90 92

G 540 625

MFI 4.2 10.4

VPF 0.11 0.09

Example 8

The solid catalyst is prepared according to the procedure described in Examples 1-3, Part A, Paragraph 2 with compound (C) obtained as described below.

80 ml of Isopar H and 18.5 ml of triethylaluminum (TEAL) are successively introduced into a 200 ml reactor, previously blown with dry nitrogen. Keeping this solution at a temperature below 50ºC, 22.5 ml of isoamyl alcohol is added drop by drop. The overall formula of this compound is:

AlEt1,5OIsoamyl1,5.

The solid catalyst contains 764 g/kg TiCl3, 1 g aluminum and 71 g EDIA, its VPI is 0.09 cm3/g and its specific surface area is 51 cm2/g.

It is used in the condensed medium propylene polymerization test, and gives an α activity of 2835, a polypropylene having a PSA of 362, an MFI of 7.6, and a G of 535, and an isotacticity index measured by NMR of 88%. The VPF of the solid polymer is 0.09.

Example 9

This example illustrates a variant synthesis of compound (C).

80 ml of Isopar H, 102 mmol of DEAC (12.7 ml) and 34 mmol of chloro-ethoxy-ethylaluminum are successively introduced into the pre-dried reactor, under a nitrogen atmosphere, to obtain a compound of the general formula Al Et1.75OEt0.25Cl.

This solution is added to a TiCl 4 solution pretreated as described in Examples 1-3, Part A, paragraph 2, to form a purple solid catalyst containing 792 g TiCl 3 , 0.8 g aluminum, and 63 g EDIA per kg solids and whose VPI and Ss are respectively 0.061 cm3/g and 165 m2/g.

The dm of the catalyst grains is between 15 and 20 mm.

The polymerization test (reference conditions) allows obtaining 350 g of polymer (α activity 3230) with the following characteristics:

PSA = 340 g/dm3

fThree = 94.8%

G = 700 N/cm2

MFI = 3 g/10 min

VPF = 0.12 cm3/g.

Example 10

Compound (C), overall formula Al Et1.65(OEt)0.35Cl is obtained by reacting 17 ml of DEAC with 3 ml of ethanol following the operational method described for example 1.

Preparation of the solid catalyst, identical to that described in Example 1, gives a purple solid containing per kg 879 g of TiCl 3 , 0.9 g of aluminum and 127 g of EDIA.

VPI is 0.067 cm3/g.

This solid catalyst used in the propylene polymerization test under reference conditions leads to an α activity of 4060, a polymer with a PSA of 358 and a VPF of 0.1 cm3/g. Other characteristics of polypropylene are: fTri = 92%, MFI = 3.8 and G = 546.

Example 11

A Obtaining a solid catalyst

1. Obtaining compound (C)

800 ml of Isopar H and 170 ml of DEAC are successively introduced under a nitrogen atmosphere into a 2-liter reactor equipped with a stirrer with a paddle rotating at 400 rpm. Then 82 ml of isoamyl alcohol is introduced drop by drop (during 1 hour) while maintaining the temperature of the solution below 50ºC.

The solution is kept at room temperature with stirring and under the introduction of nitrogen, for 16 hours before its use.

This compound can be characterized by an empirical formula:

Al Et1.45(O1isoamyl)0.55Cl.

2. Synthesis of solid catalyst

1 liter of Isopar H and 150 ml of TiCl4 are introduced into a dry 5-liter reactor equipped with a paddle mixer rotating at 220 rpm. This TiCl4 solution was maintained at 30ºC, 690 ml of EDIA and then 970 ml of the compound (C) described above were introduced slowly (30 min). The introduction of compound (C) is carried out for 60 minutes. After reducing the mixing speed to 85 rpm, 450 ml of TiCl4 is introduced for 20 minutes while raising the temperature to 100ºC after 50 minutes. The suspension is maintained at 100ºC for 2 hours and the resulting solid is isolated by decantation and then washed 7 times with 2 liters of dry hexane.

This solid purple catalyst contains per kg, 830 g of TiCl3, 1 g of aluminum and 58 g of EDIA. Its CPI is 0.07.

3. Prepolymerization of solid catalyst

All solid catalyst obtained according to point 2 (say about 317 g of solid substance based on TiCl3 complex) is suspended in 1.8 liters of hexane at 30ºC with stirring at 150 rpm.

Slowly introduce (30 minutes) 780 ml of a solution in hexane of the preactivator (hereinafter referred to as preactivator D) previously obtained by mixing in a liter of hexane, 80 g of DEAC and 176 g of 3-(3', 5'-di-tert-butyl-4- n-octadecyl hydroxyphenyl)propionate commercialized under the abbreviation IRGANOX 1076, CIBA-GEIGY. This solution is ready 15 minutes after the cessation of observed gas evolution during preparation.

After this addition, 240 ml of propylene was introduced over 30 minutes and the suspension was maintained under stirring for an additional 30 minutes.

After decanting, the obtained prepolymerized solid catalyst is washed 7 times with 2 liters of dry hexane, keeping the solid substance in suspension each time, then dried by introducing nitrogen into the fluidized bed for 2 hours at 70ºC.

The preactivated solid catalyst contains, per kg, 533 g of TiCl3, 8.2 g of aluminum, 16 g of EDIA, 228 g of polypropylene and an estimated 142 g of preactivator D.

The VPI of the catalyst is 0.09 cm3/g and the specific surface area is 8 m2/g.

B. Polymerization of propylene in monomer gases

The preactivated solid catalyst was used in a propylene polymerization experiment comprising a first stage performed in the liquid monomer and a second stage performed in the gas phase under the operating conditions detailed below.

Into the 5-liter autoclave used according to example 1, part B, a stream of nitrogen is introduced:

- 342 mg of active ingredient composed of a mixture of DEAC as used previously with triethylaluminum and ethyl benzoate (BE). The molar ratios of DEAC/BE and TEAL/BE are respectively 60/1 and 2.2/.

- 35 mg of prepolymerized solid catalyst (the molar ratio between DEAC and TiCl3 present in the solid substance should be about 15).

Then an absolute hydrogen pressure of 2 bar is established in the autoclave, 1 liter of liquid propylene is introduced with stirring and the temperature is raised to 50ºC. Polymerization is carried out under these conditions for 10 minutes. The autoclave is then degassed at an absolute pressure of 7 bar and everything is heated to 75ºC. Then an absolute hydrogen pressure of 0.8 bar is achieved, then propylene is introduced in a gaseous state until a total pressure of 21 bar is reached at the given temperature. After 4 hours of polymerization under these conditions, the reaction is stopped by introducing 25 ml of a 1 mol/1 solution of caustic soda and after washing the polymer with 2 liters of water, 214 g of dry polymer is collected.

The activity of the solid catalyst is therefore 1820 and the productivity is raised to 7280 g of polypropylene (PP) per gram of solid preactivated catalyst. This PP has an MFI of 14.8, fTri of 97 and VPF = o.15 cm3/g.

Example 12

The prepolymerized solid catalyst described in Example 1 is used in a 2-stage polymerization experiment to produce block copolymers following the operational method described above.

Into the 5-liter autoclave used according to example 1, part B, is introduced under a stream of nitrogen:

342 mg of active ingredient composed of DEAC mixture, such as was used previously with triethylaluminum and ethyl benzoate (BE). The molar ratios of DEAC/BE and TEAL/BE are 60/1 and 2.2/1, respectively.

35 mg of preactivated solid catalyst (the molar ratio between DEAC and TiCl3 present in the solid substance should be about 15).

Then an absolute pressure of 2 bars of hydrogen is realized in the autoclave, then 1 liter of liquid propylene is introduced with stirring and the temperature rises to 50ºC. It is polymerized under these conditions for 10 minutes. The autoclave is then degassed at an absolute pressure of 7 bar and heated to 75ºC. Then, an absolute hydrogen pressure of 0.6 bar is realized, then liquid propylene is introduced until an absolute pressure of 21 bar is reached at the given temperature. After 2 hours of polymerization, the autoclave is degassed to 4.5 bar by maintaining the temperature at 75ºC. In the first stage, gaseous propylene is introduced in a way that will ensure a total pressure in the autoclave of 15.4 bar at the considered temperature, and then gaseous ethylene until a total pressure of 21 bar is reached. Propylene is copolymerized with ethylene for 140 minutes while continuously supplying the autoclave with a mixture of propylene and ethylene in the gaseous state of the copolymer-enriched composition in order to maintain a constant composition of the polymerization medium.

The polymerization is stopped by introducing 25 ml of a 1 mol/1 caustic soda solution and with an α activity of 1433, 360 g of polymer is collected, which has good fluidity with the following characteristics:

MFI = 0.61

G = 185

VPF = 0.04

The proportion of elastomer in the polymer has been raised to 59 wt.%, the ethylene content in the polymer is a total of 265 g/kg.

Example 13

This example illustrates one variant of the synthesis of compound (C).

The solid catalyst is obtained as in example 1, but by replacing 7.5 ml of isoamyl alcohol with 5.8 ml of 3-methyl-1-butanediol.

The characterization of the solid catalyst as well as the polypropylene obtained in the reference test is given in Table III, below.

Table III

Properties of solid catalysts

TiCl3 content (g/kg) 847

aluminum content (g/kg) 0.7

EDIA content (g/kg) 90

CPI 0.095

Ss 90

Polymerization results

α activity in 1970

PSA 310

fThree 92

MFI 6.1

VPF 0.07

Examples 14-17

These examples illustrate the preparation of solid catalysts in the presence of an organic or inorganic support (S).

A Obtaining solid catalysts

1. Obtaining compound (C)

30 ml of Isopar H and 5.7 ml of DEAC are introduced into a 100 ml flask pre-conditioned with nitrogen. This solution is maintained with stirring at 40ºC, 1.2 ml of isoamyl alcohol is added drop by drop over 30 minutes. The solution thus obtained is maintained with stirring for 2 hours before its use.

2. Synthesis of solid catalysts

The nature and qualities of the supports (S) used in these syntheses, their characteristics and the thermal treatments to which some were subjected are previously given in Table IV, below.

Into a 1-liter autoclave equipped with a stirrer with a paddle rotating at 250 rpm, previously purged with nitrogen, 160 ml of Isopar H, 23 ml of di-isoamyl ether and a selected amount (as given in Table IV ) of the carrier (S). 20 ml of TiCl4 is then added over 30 minutes to this suspension.

This suspension is maintained at 30°C, 35.7 ml of the compound (C) described above is added over 1 hour. The temperature is then raised to 100ºC for 1 hour.

The reaction medium is maintained at this temperature for 2 hours, and then cooled to room temperature.

The liquid phase is then separated from the solid catalyst by decantation and the solid product is washed in hexane by successive decantations, after which it is dried for 1 hour under a stream of nitrogen at 70ºC.

The solid catalyst thus obtained has an aspect identical to that of the carrier, its color is purple. Table IV below gives both the properties of the obtained catalyst and its performance in the polymerization test in liquid monomer under reference conditions (example 1, part B).

Table IV

Examples 14 15 16 17

Carrier characteristics (S)

type silica alumina polymer* ;commercial name SG 532 SAEHS KETJEN CHROMOSORE ;33-50 101 ;company GRACE CARBORUN- AKZO Jhons-Man- ;DUM ville Co I ;VPS 0.6 0.33 1 0.9 ;Ssu 320 3 301 41 ;Thermal treatment of the carrier (S) ;temperature (ºC) 800 800 800 80 ;duration (hour) 16 16 16 1 ;Amount of used carrier (S) (g) ;25 90 25 25 ;Characteristics of solid catalysts ;TiCl3 content (g) /kg)363 363 134 350 118 ;EDIA content (g/kg)89 89 16 50 46 ;VPI 0.01 0.10 0.12 0.05 ;Ss 243 33 204 - ;Dm 20-200 10-150 - - ;Polymerization results ;alpha activity 2800 3980 3450 3340 ;PSA 395 359 442 330 ;fTri 89 90 90 91 ;G 445 500 575 - ;MFI 2.9 4.1 6.1 4 ;VPF 0.08 0.30 0 ,12 0.14 ;* means styrene-divinylbenzene copolymer

Claims (26)

1. A solid catalyst based on a titanium trichloride complex, applicable for the stereospecific polymerization of α-olefins, indicated by the fact that it is obtained by thermal treatment, in the presence of an activating halogenated agent, of a liquid material obtained by contacting TiCl4 pretreated with an electron-donating compound, with a compound (C) of the general formula: AlRp (Y)q X3-(p+q) (I) where R represents a hydrocarbon radical, Y represents a group selected from -OR', -SR' and -NR'R" in which R' and R" each represent a hydrocarbon radical or a hydrogen atom, X represents halogen, p is some number such that 0<p<3, q is some number such that 0<q<3, the sum (p+q) is such that 0<(p+q) ≤3. 2. Solid catalyst according to claim 1, characterized in that in the general formula (I): R represents a normal or branched radical containing 2-8 carbon atoms, Y represents the group -OR', in which R' is selected from alkyl radicals of normal or branched chains containing 1-12 carbon atoms and aryl radicals containing 6-35 carbon atoms, X represents chlorine, p is a number such that 1 ≤ p ≤ 2, q is a number such that 0.1 ≤ q ≤ 3. 3. A solid catalyst according to claim 1 or 2, characterized in that the electron donor compound is chosen from among aliphatic ethers. 4. Solid catalyst according to claims 1-3, characterized in that the activating halogenated agent is selected from inorganic halogenated compounds. 5. Solid catalyst according to claim 4, characterized in that the activating halogenated agent is TiCl4. 6. A solid catalyst according to one of claims 1-5, characterized in that it is obtained by adding an organic or inorganic carrier (S) to the medium for obtaining a solid substance, at some point. 7. Solid catalyst according to claim 6, characterized in that the carrier (S) is added before thermal treatment of the liquid material. 8. A solid catalyst according to one of claims 6 and 7, characterized in that the carrier (S) is an organic preformed polymer. 9. A solid catalyst according to one of claims 6 and 7, characterized in that the carrier (S) is selected from oxygen compounds, such as oxides of silicon, aluminum, magnesium, titanium, zirconium and their mixtures. 10. Process for obtaining a solid catalyst based on a titanium trichloride complex, applicable for the stereospecific polymerization of α-olefins, characterized by the fact that the liquid material obtained by contacting TiCl4 is pre-treated using an electron-donating compound, with compound (C) corresponding to the general formula: AlRp (Y)q X3-(p+q) (I) where R represents a hydrocarbon radical, Y represents a group selected from -OR', -SR' and NR'R" in which R' and R" each represents a hydrocarbon radical or a hydrogen atom, X represents halogen p is some number such that 0<p<3, q is some number such that 0<q<3, the sum (p+q) is such that 0<(p+q) ≤ 3, subjected to heat treatment in the presence of a halogenated activating agent. 11. The method according to claim 10, indicated by the fact that the amount of compound (C) which is contacted with previously processed TiCl4 is such that the atomic ratio between aluminum contained in compound (C) and titanium contained in TiCl4 is between 0.1 and 8. 12. The method according to claim 10, characterized in that the thermal treatment is performed under conditions that lead to the deposition of mostly solid particles based on titanium trichloride. 13. The method according to claim 10, characterized in that the activating halogenated agent is added at the beginning of the heat treatment. 14. The method according to claim 10, characterized in that the halogenated activator is TiCl4 which originates from an excess of the initial TiCl4 which is not reduced. 15. The method according to one of the claims 10-14, characterized in that the amount of activation agent used is between 0.5 and 10 moles per mole of titanium trichloride present in the liquid material. 16. The method according to one of the claims 10-15, characterized in that the heat treatment is followed by ripening. 17. The method according to one of claims 10-16, characterized in that an organic or inorganic carrier (S) is added to the mixture for obtaining the mentioned solid substance at some point. 18. Process for polymerization of α-olefin in the presence of a catalytic system comprising an activator selected from among organometallic compounds of metals of groups Ia, IIa, IIb and IIIb of the periodic table and a solid catalyst based on a titanium trichloride complex, indicated by the fact that the mentioned solid substance is obtained by heat treatment in the presence of a halogenated activator, liquid matter obtained from contacting TiCl4 with an electron-donor compound, with compound (C) corresponding to the general formula: AlRp (Y)q X3-(p+q) (I) where R represents a hydrocarbon radical, Y represents a group selected from -OR', -SR' and NR'R" in which R' and R" represent each hydrocarbon radical or hydrogen atom, X represents halogen p is some number such that 0<p<3, q is some number such that 0<q<3, the sum (p+q) is such that 0<(p+q) ≤ 3. 19. The method according to claim 18, characterized in that the solid catalyst is obtained by adding to the mixture for obtaining the mentioned solid substance, at some point, an organic or inorganic carrier (S). 20. The method according to one of claims 18-19, characterized in that the activator is selected from compounds of the formula: Al R'"x Z3-x where R'" is a hydrocarbon radical containing 1-18 carbon atoms, Z is halogen, x is some number such that 0<x ≤ 3. 21. The method according to one of claims 18 and 19, characterized in that it is applicable in the stereospecific polymerization of propylene. 22. The method according to one of claims 18 and 19, characterized in that it is applicable in the stereospecific polymerization of propylene in suspension in an inert hydrocarbon solvent. 23. The method according to one of claims 18 and 19, characterized in that it is applicable in the stereospecific polymerization of propylene in the monomer in the liquid state. 24. The method according to one of claims 18 and 19, characterized in that it is applicable in the stereospecific polymerization of propylene in the gas phase. 25. The method according to one of claims 18 and 19, characterized by the fact that it is applicable in the production in the gas phase of block copolymers that are composed of blocks of crystalline homopolymer of propylene and blocks of statistical copolymers containing 40-70 mol.% propylene and 60- 30 mol.% ethylene. 26. The method according to claim 24, characterized in that the content of homopolymer blocks constitutes 30-90 wt.% of the total polymer.