CATALYSTS AND PROCESSES FOR THE POLYMERIZATION OF OLEFINS

Abstract: Catalysts for the polymerization of olefins comprise the product of the reaction between: (A) a titanium, zirconium or hafnium product with substituted cyclopentadiene ligands, (B) a mixture of two organometallic aluminium compounds, with at least one of the groups bound to the aluminium being other than a linear alkyl, and (C) water. When used in the polymerization of olefins, these catalysts show higher activities, at short residence times, than corresponding catalysts obtained from the individual components of the above-mentioned mixtures of aluminium compounds.

Description: TITLE : CATALYSTS AND PROCESSES FOR THE POLYMERIZATION OF OLEFINS The present invention relates to catalysts for the polymerization of olefins, obtained from cyclopentadienyl com¬ pounds, organometallic aluminium compounds and water. Homogeneous catalyst systems for the polymerization of olefins are known which comprise a metallocene and the product of the reaction between water and an aluminium alkyl, where the alkyl is other than methyl. In European Patent Application EP 384 171, catalysts are described which are suitable for the polymerization of olefins and comprise the product of the reaction between: (A) a metallocene compound of the general formula: (C 5 R' π ) m R" (C 5 R' n )MX 3 . m where (C 5 R' n ) is a cyclopentadienyl group in which R' is hydrogen, an alkyl, alkenyl, aryl, alkylaryl or arylalkyl rad¬ ical having from 1 to 20 C atoms or a group CR 2 SiR 3 or a group SiR 3 with R being defined as for R' , or two (or four) substituents R' of one and the same cyclopentadienyl group form one (or two) rings having from 4 to 6 C atoms, R" is a divalent radical selected from an optionally substituted alkylene group having from 1 to 8 C atoms, an SiR 7 , PR or NR group with R being defined as for R' , which forms a bridge link between two cyclo¬ pentadienyl groups, X is hydrogen, halogen, -OMX(C 5 R' n ) 2 , -OH or -OR with R being defined as for R' , or a hydrocarbon radical having the meaning of R' , M is a transition metal of valency 3 or 4, selected from Ti, Zr or Hf, p is 0 or 1, m is 0, 1 or 2, and, if m = 0, p = 0 and, if p = 0, at least one radical R' is other than hydrogen, n = 4, if p = 1, and n = 5, if p = 0; and (B) an alumoxane of the formula: R 1 . R3 \ Al — 0 — - * */ \ R< in which R 1 , R 2 , R 3 and R 4 can generically be alkyl, alkenyl or alkylaryl radicals having 2-20 carbon atoms. The alumoxanes (B) can be prepared by reacting the cor¬ responding trialkylaluminium with water in a 2:1 molar ratio. In the embodiment examples, alumoxanes are used in which R 1 , R 2 , R 3 and R 4 are ethyl, isobutyl or 2-methylpentyl groups. European Patent Application EP 575 875 describes homogene¬ ous catalyst systems for the polymerization of olefins, obtained by contacting the following components: (A) a cyclopentadienyl compound of the general formula: (CsR'x-nHs-x) R 2 m (C 5 R , y . m H 5 . y ) n MQ 3 . n in which M is Ti, Zr or Hf, C 5 R 1 χ.m H 5.χ and C 5 R 1 y.rn H 5 . y are cyclopentadiene rings substituted in the same way or dif¬ ferent ways, the substituents R 1 which can be identical or different are alkyl, alkenyl, aryl, alkylaryl or arylalkyl radicals which have from 1 to 20 carbon atoms and can also contain Si or Ge atoms, or are Si(CH 3 ) 3 groups, or also two or four substituents R 1 of one and the same cyclopentadienyl group can form one or two rings having from 4 to 6 carbon atoms, R 2 is a group forming a bridge link between the two cyclopentadiene rings and is selected from CR 3 2 , C 2 R 4 , SiR 2 , Si 2 R 3 4 , GeR 3 2 , Ge 2 R 3 4 , R 3 2 SiCR 3 2 , NR 1 or PR 1 , with the substituents R 3 which can be identical or dif¬ ferent being R 1 or hydrogen, or also two or four sub¬ stituents R 3 can form one or two rings having from 3 to 6 carbon atoms, the substituents Q which can be identical or different are halogen, hydrogen, OH, SH, R 1 , OR 1 , SR 1 , NR 1 -) or PR 1 --,, m can be 0 or 1, n can be 0 or 1, being 1 if m = 1, x is an integer between (m+l) and 5, and y is an integer between m and 5; (B) an organometallic aluminium compound of the general formula A1R 3 3.Z H Z , in which the substituents R 3 which can be identical or different are alkyl, alkenyl or alkylaryl radicals which have from 1 to 10 carbon atoms and can also contain Si or Ge atoms, with the proviso that at least one the substituents R 3 is other than a linear alkyl group, and z is 0 or 1; and (C) water. The molar ratio between the organometallic aluminium com¬ pound and the water is between 1:1 and 100:1. In the embodiment examples, the organometallic aluminium compounds used are only triisobutylaluminium and triisohexylaluminium. In Italian Patent Application No. MI/94A/1516, homogeneous catalyst systems for the polymerization of olefins are described which possess an activity improved over those exemplified in the abovementioned patent application EP 575 875, which systems com¬ prise the product obtained by contacting the following componentε: (A) a cyclopentadienyl compound of the formula: ( C 5 R x-m H 5-χ) R ~m( C 5 R y-m H 5-y) n M0 -3-n in which M is Ti, Zr or Hf, C 5 R' χ.m H 5.χ and C j R 1 H 5 are cyclopentadiene rings substituted in the same way or dif¬ ferent ways, the substituents R 1 which can be identical or different are alkyl, alkenyl, aryl, alkylaryl or arylalkyl radicals which have from 1 to 20 carbon atoms and can also contain Si or Ge atoms, or are Si(CH 3 ) 3 groups, or also two or four substituents R 1 of one and the same cyclopentadienyl group can form one or two rings having from 4 to 6 carbon atoms, R~ is a group forming a bridge link between the two cyclopentadiene rings and is selected from CR 3 2 , C 2 R 3 4 , SiR 3 2 , Si 7 R 3 4 , GeR 3 2 , Ge 2 R 3 4 , R 3 2 SiCR 3 2 , NR 1 or PR 1 , with the substituents R 3 which can be identical or dif¬ ferent being R ! or hydrogen, or also two or four sub¬ stituents R 3 can form one or two rings having from 3 to 6 carbon atoms, the substituents Q which can be identical or different are halogen, hydrogen, R 1 , OR 1 , SR 1 , NR 1 -, or PR 1 --), m can be 0 or 1, n can be 0 or 1, being 1, if — 1 , x is an integer between (m+l) and 5 and y is an integer between m and 5; (B) an organometallic aluminium compound of the formula: Al-(CH 2 -CR 4 R 5 R 6 ) 3 _ Z H Z in which R 4 is an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R 5 is an alkyl, alkenyl or alkylaryl group with a branched chain having from 3 to 10 carbon atoms, or R 4 and R 5 are fused together to form a ring having from 4 to 6 carbon atoms, R 6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 car¬ bon atoms and z is 0 or 1; and (C) water. The molar ratio between the organometallic aluinium com¬ pound and the water is between 1:1 and 100:1. The polymerization yields of the catalysts described in the abovementioned patent applications are, albeit relatively high, not altogether satisfactory if the residence times of the reac¬ tion mixture in the reactor are short. This is particularly important in industrial polymerization processes, especially in those which operate continuously, where it is very advantageous to operate with short residence times. It would therefore be desirable to improve the productivity of the abovementioned catalysts at short residence times. It has now been found, unexpectedly, that catalysts for the polymerization of olefins, of the type of those described in the abovementioned patent applications, obtained from particular mixtures of organometallic aluminium compounds, show superior activities at short residence times than the corresponding cata¬ lysts obtained from the individual components of the abovementioned mixtures of aluminium compounds. The catalysts which are the subject of the present invention comprise the product obtained by contacting the fol¬ lowing components: (A) a cyclopentadienyl compound of the formula (I) : (C 5 Rl χ- m H 5 -χ) R2 ,„(C 5 R' y . m H 5 . y ) n MQ 3 . n (I) in which M is Ti, Zr or Hf, C j R'^H^ and C 5 R 1 y.m H 5 . y are cyclopentadiene rings substituted in the same way or differ¬ ent ways, the substituents R ! which can be identical or dif¬ ferent are alkyl, alkenyl, aryl, alkylaryl or arylalkyl rad¬ icals which have from 1 to 20 carbon atoms and can also con¬ tain Si or Ge atoms, or Si(CH 3 ) 3 groups, or also two or four substituents R 1 of one and the same cyclopentadienyl group can form one or two rings having from 4 to 6 carbon atoms, R- is a group forming a bridge link between the two cyclo¬ pentadiene rings and is selected from CR 3 2 , C-,R 3 , SiR 3 2 , Si 2 R 3 4 , GeR 3 2 , Ge 2 R 3 4 , R 3 2 SiCR 3 2 , NR 1 or PR 1 , with the substituents R 3 which can be identical or different being R 1 or hydrogen, or also two or four substituents R 3 can form one or two rings having from 3 to 6 carbon atoms, the sub¬ stituents Q which can be identical or different are halogen, hydrogen, R 1 , OR 1 , SR 1 , NR ] 2 or PR 1 --., m can be 0 or 1, n can be 0 or 1, being 1, if m = 1, x is an integer between (m+l) and 5, and y is an integer between m and 5; (B) a mixture composed of: (Bl) 1-99 mol-% of an organometallic aluminium compound of the formula (II) : A1-(CH 2 -CR 4 R 5 R 6 ) 3.Z H Z (II) in which R 4 is an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R 5 is an alkyl, alkenyl or alkylaryl group with a branched chain having from 3 to 10 carbon atoms, or R 4 and R 5 are fused together to form a ring having from 4 to 6 carbon atoms, R 6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, and z is 0 or i; (B2) 1-99 mol-% of an organometallic aluminium compound of the formula (III) : A1R 3 3.W H W (III) in which the substituents R 3 which can be identical or different are alkyl, alkenyl or alkylaryl radicals which have from 1 to 10 carbon atoms and can also con¬ tain Si or Ge atoms, with the proviso that at least one of the substituents R 3 is other than a linear alkyl group, and w is 0 or 1, the compounds of the formula (II) defined above being excluded; and (C) water. The molar ratio between the total of the organometallic alu¬ minium compounds and the water is between 1:1 and 100:1, prefer¬ ably between 1:1 and 50:1 and more preferably between 1:1 and 10:1. The molar ratio between the aluminium and the metal of the cyclopentadienyl compound is between about 50 and 10,000, pre¬ ferably between about 500 and 5000 and more preferably between 1000 and 2000. The molar ratio (B1)/(B2) between the two components of the mixture (B) of organometallic aluminium compounds is preferably between about 10:90 and about 90:10, and more preferably is between about 25:75 and about 75:25. Those mixtures (B) are par¬ ticularly preferred in which the components (Bl) and (B2) are present in approximately equimolar quantities. In the case of m=0, particularly suitable cyclopentadienyl compounds are those in which M is Zr and the groups C 5 R' x.m H5 .x and C5R 1 H 5 are pentamethyl-cyclopentadienyl, indenyl or 4,5,6,7- tetrahydroindenyl, while the substituents Q are chlorine atoms or hydrocarbon groups containing from 1 to 7 carbon atoms. Non-limiting examples of cyclopentadienyl compounds (A) with m = 0 are: (Me 3 Cp) 2 MCl 2 (Me 4 Cp) 2 MCl 2 (Me 5 Cp) 2 MCl 2 (Me 5 Cp) 2 MMe 2 (Me 5 Cp) 2 M(0Me) 2 (Me 5 Cp) 2 M(C 6 H 5 ) 2 (Me 5 Cp) 2 M(CH 3 )Cl (EtMe 4 Cp) 2 MC1 2 [ (C 6 H 5 )Me 4 Cp] 2 MCl 2 (Et 5 Cp) 2 MCl 2 (Me 5 Cp) 2 M(C 6 H 5 )Cl (Ind) 2 MCl 2 (Ind) 2 MMe 2 (H 4 Ind) 2 MCl 2 (H 4 Ind) 2 MMe 2 [Si(CH 3 ) 3 Cp] 2 MCl 2 {[Si(CH 3 ) 3 ] 2 Cp} 2 MCl 2 (Me 4 Cp) (Me 5 Cp)MCl 2 (Me 5 Cp)MCl 3 (Me 5 Cp)MBenz 3 (Ind)MBenz 3 (H 4 Ind)MBenz 3 where Me = methyl, Et = ethyl, Cp = cyclopentadienyl, Ind = indenyl, H 4 Ind = 4 , 5, 6, 7-tetrahydroindenyl, Benz = benzyl, M is Ti, Zr or Hf and preferably is Zr. In the case of m = 1, particularly suitable cyclopentadienyl compounds are those in which M is Zr and the groups C 5 R 1 χ . m H 5 . χ and C 5 R ] H 5 are tetramethyl-cyclopentadienyl, indenyl or tetrahydroindenyl and R 2 is a group (CH 3 ) 2 Si or C 2 H 4 , while the substituents Q are chlorine atoms or hydrocarbon groups having from 1 to 7 carbon atoms. Non-limiting examples of cyclopentadienyl compounds (A) with = 1 are: Me 2 Si(Me 4 Cp) 2 MCl 2 Me 2 Si(Me 4 Cp) 2 MMe 2 Me 2 C(Me 4 Cp) (MeCp)MCl 2 Me 2 Si(Ind) 2 MCl 2 Me 2 CSi(Ind) 2 MMe 2 Me 2 Si (Me 4 Cp) 2 MC1 (OEt) C 2 H 4 (Ind) 2 MCl 2 C 2 H 4 (Ind) 2 MMe 2 C 2 H 4 (Ind) 2 M(NMe 2 ) 2 C 2 H 4 (H 4 Ind) 2 MCl 2 C 2 H 4 (H 4 Ind) 2 MMe 2 C 2 H 4 (H 4 Ind) 2 M (NMe 2 ) OMe Ph(Me)Si(Ind) 2 MCl 2 Ph 2 Si(Ind) 2 MCl 2 Me 2 C(Flu) (Cp)MCl 2 C 2 H 4 (Me 4 Cp) 2 MCl 2 C 2 Me 4 (Ind) 2 MCl 2 Me 2 SiCH 2 (Ind) 2 MCl 2 C 2 H 4 ( 2 -Melnd ) 2 MC1 2 C 2 H 4 (3-MeInd) 2 MCl 2 C 2 H 4 (4 , 7-Me 2 Ind) 2 MC1 2 C 2 H 4 (5,6-Me 2 Ind) 2 MCl 2 where Me = methyl, Cp = cyclopentadienyl, Ind = indenyl, Flu = fluorenyl, Ph = phenyl, H 4 Ind = 4 , 5, 6, 7-tetrahydroindenyl, M is Ti, Zr or Hf and preferably is Zr. In the organometallic aluminium compound of the formula (II) which can be used as component (Bl) , R 4 is preferably a methyl or ethyl group, while R 6 is preferably a hydrogen atom. Particularly preferred aε components (Bl) are the organometallic aluminium compoundε in which R 4 is a methyl group, R 5 is an alkyl group with a branched chain having a num¬ ber of carbon atoms greater than 4 and R 6 is a hydrogen atom. Non-limiting examples of organometallic aluminium compounds which can be used as components (Bl) are: tris-(2,4, 4-trimethyl-pentyl) -aluminium and di-(2,4,4-trimethyl-pentyl) -aluminium hydride. The particularly preferred compound is tris-(2,4,4-trimethyl- pentyl) -aluminium (TIOA) . In the organometallic aluminium compound of the formula (II) which can be used as component (Bl) , preferably all the substituents R 7 are non-linear alkyl, alkenyl or alkylaryl rad¬ icals. More preferably, all the substituents R 7 of the organometallic aluminium compound are isoalkyl radicals. Non-limiting examples of organometallic aluminium compounds which can be used as components (B2) are: triethylalu inium, di-methylisobutylaluminium, methy1-di-isobutylaluminium, tri-isobutylaluminiu , di-isobutylaluminiu monohydride and tris-(2,2-dimethylpropyl) aluminium. The particularly preferred compound is triisobutylaluminium (TIBA) . The components constituting the catalystε of the present invention can be brought into contact in various ways. In an embodiment example, the mixture of aluminium compounds is contacted with water, and then the reaction product thus obtained iε brought into contact with the cyclopentadienyl com¬ pound. A further subject of the present invention is therefore a catalyst for the polymerization of olefins, comprising the prod¬ uct obtained by contacting the following componentε: (A) a cyclopentadienyl compound of the formula (I) : ( C 5 R l x . m ≡ 5 . x )R 2 m (C 5 R ] y . m H 5 . y ) n MQ 3 .„ (I) in which M is Ti, Zr or Hf, C 5 R 1 χ.m H 5.χ and C 5 R 1 H 5.y are cyclopentadiene rings substituted in the same way or differ¬ ent ways, the substituents R 1 which can be identical or dif¬ ferent are alkyl, alkenyl, aryl, alkylaryl or arylalkyl rad¬ icals which have from 1 to 20 carbon atoms and can also con¬ tain Si or Ge atoms, or Si(CH 3 ) 3 groups, or also two or four substituentε R 1 of one and the εame cyclopentadienyl group can form one or two rings having from 4 to 6 carbon atoms, R 2 is a group forming a bridge link between the two cyclo¬ pentadiene rings and iε εelected from CR 3 7 , C 2 R 3 4 , SiR 3 2 , Si 2 R 3 4 , GeR 3 2 , Ge*,R 3 4 , R 3 2 SiCR 3 2 , NR 1 or PR 1 , with the εubεtituentε R 3 which can be identical or different being R 1 or hydrogen, or also two or four subεtituents R 3 can form one or two rings having from 3 to 6 carbon atoms, the substituents Q which can be identical or different are halogen, hydrogen, R 1 , OR 1 , SR 1 , NR ] or PR l 2 , m can be 0 or 1, n can be 0 or l, being 1, if m = 1, x iε an integer between (m+l) and 5, and y iε an integer between m and 5; and (B) the product of the reaction between water and a mixture conεisting of: (Bl) 10-90 mol-% of an organometallic aluminium com¬ pound of the formula (II) : A1-(CH 2 -CR 4 R 5 R 6 ) 3.Z H Z (II) in which R 4 iε an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R 5 is an alkyl, alkenyl or alkylaryl group with a branched chain having from 3 to 10 carbon atoms, or R 4 and R 5 are fused together to form a ring having from 4 to 6 carbon atoms, R 6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, and z is 0 or 1; and (B2) 10-90 mol-% of an organometallic aluminium com¬ pound of the formula (III) : A1R 3 3.W H W (III) in which the substituents R 3 which can be identical or different are alkyl, alkenyl or alkylaryl radicals which have from 1 to 10 carbon atoms and can also con¬ tain Si or Ge atoms, with the proviso that at least one of the substituents R 3 is other than a linear alkyl group, and w is 0 or 1, the compounds of the formula (II) defined above being excluded. The molar ratio between the organometallic aluminium compounds and the water is between 1:1 and 100:1, preferably between 1:1 and 50:1, more preferably between 1:1 and 10:1. The componentε of the catalysts of the present invention can be brought into contact by various methods. For example, it is possible gradually to add water to the mixture of aluminium compounds in solution in an inert aliphatic or aromatic hydrocarbon solvent such as, for example, heptane or toluene. The solution thuε obtained iε contacted with a solution of a cyclopentadienyl compound in a suitable solvent as, for example, toluene. According to another way of proceeding, the water can be introduced in the monomer, or in one of the monomers, to be polymerized; in thiε case, the mixture of aluminium compounds and the cyclopentadienyl compound are first brought into contact before they are uεed in the polymerization. Moreover, the water can be made to react in a combined form aε a hydrated salt, or it can be adεorbed or abεorbed on an inert εupport such as sil¬ ica. Another preparation method is the reaction of the aluminium compoundε with boric anhydride or boric acid. The catalyεts of the present invention can also be used on inert supports. This is effected by depositing the cyclopentadienyl compound, or the product of the reaction there¬ of with the aluminium compoundε pre-reacted with water, or the aluminium compoundε pre-reacted with water and then the cyclopentadienyl compound, on inert εupports such as, for example, silica, alumina, styrene/ divinylbenzene copolymers, polyethylene or polypropylene. A particularly suitable class of inert supports which can be used is that constituted by porous organic supports functionalized with groups having active hydrogen atoms. Those are particularly preferred in which the organic support is a partially crosεlinked εtyrene polymer. Supports of this type are deεcribed in European Application EP-633 272, the content of which is understood to be incorporated in the present descrip¬ tion. The solid compound thus obtained, in combination with the further addition of aluminium alkyl compoundε, whether pre- reacted with water or not, can be uεed in the gas-phase polymerization. The catalysts of the present invention can be used in the polymerization reactions of olefins. A further subject of the present invention is therefore a procesε for the polymerization of at least one olefin of the formula CH 2 =CHR, in which R is hydrogen or an alkyl radical hav¬ ing from 1 to 20 carbon atomε, compriεing the polymerization reaction of the εaid olefinε in the presence of a catalyst as described above. The catalysts according to the present invention can advan¬ tageously be uεed in the homopolymerization of ethylene and, in particular, for the preparation of HDPE, and for the copolymerization of ethylene and, in particular, for the prep¬ aration of LLDPE. The LLDPE copolymerε which are obtained have a content of ethylene unitε of between 80 and 99 mol-%. Their denεity is between 0.87 and 0.95 g/cm 3 and they are characterized by a uni¬ form distribution of the comonomer units within the polymer chain. The olefinε which can be used aε comonomers comprise α- olefinε of the formula CH-,=CHR, where R iε a linear or branched or cyclic alkyl radical having from 1 to 20 carbon atoms, or cycloolefins. Examples of such olefins are propylene, 1-butene, 1-pentene, 4-methyl-l-pentene, 1-hexene, l-octene, allylcyclohexane, cyclopentene, cyclohexene, norbornene and 4,6- dimethyl-1-heptene. The units derived from the olefins of the formula CH-,=CHR or from the cycloolefinε are present in the copolymers in quantities from 1 to 20 mol-%. The copolymers can also contain units derived from polyenes, in particular conjugated or non-conjugated, linear or cyclic dienes such as, for example, 1, 4-hexadiene, isoprene, 1,3- butadiene, 1, 5-hexadiene and 1, 6-heptadiene. A further use of interest is the preparation of elastomeric copolymers of ethylene with α-olefins of the formula CH 2 =CHR, where R is an alkyl radical having from 1 to 10 carbon atoms, the said copolymers optimally containing minor proportions of unitε derived from a polyene. The εaturated elaεtomeric polymerε obtainable by meanε of the catalysts of the present invention contain from 15 to 85 mol-% of ethylene units, the complement up to 100 consisting of units of one or more α-olefins and/or of one non-conjugated diolefin capable of cyclopolymerizing. The unsaturated elastomeric copolymers contain, besides the units derived from the polymerization of ethylene and α-olefins, alεo minor propor¬ tions of unsaturated units derived from the copolymerization of one or more polyenes. The content of unsaturated units can vary from 0.1 to 5% by weight and is preferably between 0.2 and 2% by weight. The copolymerε obtainable are characterized by valuable propertieε, such aε a low aεh content and a uniform diεtribution of the comonomers in the copolymer chain. The α-olefins which can be used comprise, for example, propylene, 1-butene and 4-methyl-l-pentene. The preferred α- olefin is propylene. The non-conjugated diolefins capable of cyclopolymerizing, which can be uεed, are 1, 5-hexadiene, 1, 6-heptadiene and 2- methyl-1, 5-hexadiene. The polyeneε capable of giving unsaturated units, which can be used, are: conjugated dienes such aε, for example, butadiene and isoprene; non-conjugated linear dienes such aε, for example, trans- 1, 4-hexadiene, cis-1, 4-hexadiene, 6-methyl-l, 5-heptadiene, 3,7-dimethyl-l, 6-octadiene and 11-methyl-l, 10-dodecadiene; monocyclic diolefins such aε, for example, cis-1,5- cyclooctadiene and 5-methyl-l, 5-cyclooctadiene; bicyclic diolefinε εuch aε, for example, 4,5,8,9- tetrahydroindene and 6- and/or 7-methyl-4,5,8,9- tetrahydroindene; alkenyl- or alkylidene-norborneneε such as, for example, 5- ethylidene-2-norbornene, 5-isopropylidene-2-norbornene, exo- 5-iεopropenyl-2-norbornene and 5-vinyl-2-norbornene; polycyclic diolefinε εuch as, for example, dicyclo¬ pentadiene, tricyclo[6.2.1.0 2,7 ]4, 9-undecadiene and its 4- methyl derivative. Preferred polyenes are 5-ethylidene-2-norbornene, trans-1,4- hexadiene and ciε-l, 4-hexadiene. 5-Ethylidene-2-norbornene (ENB) is particularly preferred. The polymerization procesεes, which use the catalysts of the invention, can be carried out in the liquid phaεe, in the pres¬ ence or absence of an inert hydrocarbon solvent, or in the gas phase. The hydrocarbon solvent can be aromatic such as toluene, or aliphatic εuch aε propane, hexane, heptane, isobutane and cyclohexane. The polymerization temperature is generally between -100°C and 250°C. In particular, in the processes for the preparation of HDPE or LLDPE, it is generally between 20°C and 150°C and especially between 40°C and 90°C. In the processes for the prep¬ aration of elastomeric copolymers, it is generally between 20°C and 100°C and especially between 30°C and 80°C. The molecular weight of the polymers can be varied εimply by altering the polymerization temperature, the type or the concen¬ tration of the catalyεt componentε or uεing molecular weight regulatorε such as, for example, hydrogen. The molecular weight distribution can be varied by using mixtures of different cyclopentadienyl compounds or by carrying out the polymerization in several stages which differ in the polymerization temperatureε and/or in the concentrations of the molecular weight regulator. The catalyεt componentε can be brought into mutual contact before the polymerization. The contact time iε generally between 1 and 60 minuteε, preferably between 5 and 20 minutes. The pre- contact concentrations for the cyclopentadienyl compound are between 10 "2 and 10 "8 mol/1, while, for the product of the reac¬ tion between aluminium alkyl and water, they are between 10 and IO "3 mol/1. The precontact is in general effected in the preεence of a hydrocarbon εolvent and, if appropriate, small quantities of monomer. Figure 1 showε a graph of the productivity, to give ethylene/propylene copolymers, of catalyεts according to the invention and according to the known technology aε a function of the polymerization time. This graph clearly shows the higher productivity of the catalysts according to the invention as com¬ pared with known catalystε at short polymerization times. The following examples are given for illustrative purposes and do not limit the invention. CHARACTERIZATIONS The intrinsic viscosity [ η ] was measured in tetralin at 135°C. The comonomer content in the elastomeric ethylene/propylene copolymers waε determined by IR. The catalyεt componentε were prepared as follows: CYCLOPENTADIENYL COMPOUNDS rac-ETHYLENE-BIS (4,5.6,7-TETRAHYDROINDENYL) ZIRCONIUM DICHLORIDE (r-EBTHlZrci 2 ) This was prepared according to the procedure described in EP 575,875. ORGANOMETALLIC ALUMINIUM COMPOUNDS TRI-ISOBUTYLALUMINIUM [TIBA] The commercial product from WITCO was uεed. TRIS- (2.4,4-TRIMETHYL-PENTYL) -ALUMINIUM [TIOA] This waε prepared according to the method deεcribed in Liebigε Ann. Chem. vol. 629, Ziegler et al. "Aluminumtrialkyle und Dialkyl-aluminumhydride aus Aluminu iεobutyl-Verbindungen [Aluminium trialkyls and dialkyl-aluminium hydrideε from alumin¬ ium iεobutyl compoundε]", pageε 14-19.0. EXAMPLES 1-3 Preparation of elastomeric 1324 g (2 litres) of n-hexane, 44.7 g of ethylene, 388 g of propylene and 0.94 mmol of water were introduced at ambient tem- perature into a 4.25 litre autoclave fitted with εtirrer, mano¬ meter, temperature indicator, catalyεt-charging system, monomer feed lines and thermoεtat jacket, and purified by purging with ethylene at 80°C. The catalyst solution was prepared by adding the quantities of aluminium alkyls given in Table 1 to a εuεpension of 0.8 mg of r-EBTHI 2 ZrCl 9 in a hydrocarbon solvent consisting of about 2 ml of solvent per mg of metallocene. Stirring of the mixture was continued for 5 minutes at a temperature of 20°C, and the sol¬ ution was then injected into the autoclave under ethylene pres¬ sure at a temperature about 2°C lower than the polymerization temperature. The temperature was then raised within about 2 min¬ utes to 50°C and kept constant for the whole duration of the polymerization. The pressure was kept constant at a value of 9.6 bar by feeding an ethylene/propylene mixture in a 60:40 ratio. The con¬ sumption of monomers fed was monitored at regular time intervals (2 minuteε) throughout the whole duration of the polymerization. When the total quantity of monomerε fed reached a value of 60 g, the reaction waε stopped by degaεsing the monomers. The polymer obtained was dried in an oven at 60°C in vacuo. The data relating to the polymerization and to the characterization of the copolymer obtained are given in Table 1. The data relating to the consumption of monomers as a func¬ tion of the polymerization time are given in Table 2. EXAMPLES 4-5 (comparison) Preparation of elastomeric C 2 /C-,-copolymers The procedure deεcribed in Examples 1-3 was followed, but with the difference that only one of the componentε of the mix¬ ture (B) of aluminium compoundε waε uεed. The data relating to the polymerization and to the characterization of the polymer obtained are given in Table 1. The data relating to the monomer conεumption aε a function of the polymerization time are given in Table 2. TABLE 1 TABLE 2 31 minuteε 33 minuteε

Claims: CLAIMS 1. Catalyst for the polymerization of olefinε, comprising the product of the reaction between the following com¬ ponents: (A) a cyclopentadienyl compound of the formula (I) : (Cs-R'x-mHs- ) R2 m ( 5 Rl y - ιn H 5-y) „MQ 3 -„ (I) in which M is Ti, Zr or Hf, C 5 R' χ.m H 5.χ and C 5 R 1 y.rn H 5.y are cyclopentadiene rings substituted in the same way or different ways, the εubεtituents R 1 which can be ident¬ ical or different are alkyl, alkenyl, aryl, alkylaryl or arylalkyl radicalε which have from 1 to 20 carbon atoms and can also contain Si or Ge atoms, or Si(CH 3 ) 3 groups, or also two or four substituentε R 1 of one and the same cyclopentadienyl group can form one or two ringε having from 4 to 6 carbon atomε, R 2 is a group forming a bridge link between the two cyclopentadiene rings and is selected from CR 3 2 , C 9 R 3 4 , SiR 3 2 , Si 2 R 3 4 , GeR 3 7 , Ge 7 R 3 4 , R 2 SiCR 3 2 , NR 1 or PR 1 , with the substituents R 3 which can be identical or different being R 1 or hydrogen, or also two or four subεtituentε R 3 can form one or two rings having from 3 to 6 carbon atoms, the substituents Q which can be identical or different are halogen, hydrogen, R 1 , OR 1 , SR 1 , NR ! 2 or PR' 2 , m can be 0 or 1, n can be 0 or 1, being 1, if m = 1, x is an inte¬ ger between (m+l) and 5, and y is an integer between m and 5; (B) a mixture composed of: (Bl) 1-99 mol-% of an organometallic aluminium compound of the formula (II) : A1-(CH 2 -CR 4 R 5 R 6 ) 3.Z H Z (II) in which R 4 is an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R 5 is an alkyl, alkenyl or alkylaryl group with a branched chain having from 3 to 10 carbon atoms, or R 4 and R 5 are fused together to form a ring having from 4 to 6 carbon atoms, R 6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, and z is 0 or i; (B2) 1-99 mol-% of an organometallic aluminium compound of the formula (III) : in which the substituents R 3 which can be identical or different are alkyl, alkenyl or alkylaryl radicals which have from 1 to 10 carbon atoms and can also con¬ tain Si or Ge atoms, with the proviso that at least one of the substituentε R 3 is other than a linear alkyl group, and w is 0 or 1, the compounds of the formula (II) defined above being excluded; and (C) water, the molar ratio between the organometallic aluminium compounds and the water being between 1:1 and 100:1. Catalyst according to Claim 1, wherein the molar ratio between the organometallic aluminium compound and the water is between 1:1 and 10:1. Catalyεt according to Claim 1, wherein the molar ratio between the aluminium of the organometallic aluminium compound and the metal M of the cyclopentadienyl com¬ pound is between 50 and 10,000. Catalyst according to Claim 1, wherein in the cyclopentadienyl compound (A), m = 0, the groups C 5 R 1 x _ m H 5 _ x and C 5 R' H 5 are pentamethyl¬ cyclopentadienyl, indenyl or 4, 5, 6, 7-tetrahydroindenyl, M is Zr and the εubεtituentε Q are chlorine atoms or hydrocarbon groups containing from 1 to 7 carbon atoms. Catalyst according to Claim 1, wherein in the cyclopentadienyl compound (A) , m = l, n -= 1, R 2 is a divalent group (CH 3 ) 2 Si or C 2 H 4 and the groups C j R^^H^ and C g R' y ^H g.y are selected from tetramethyl-cyclo- pentadienyl, indenyl or 4 , 5, 6, 7-tetrahydroindenyl, 2- methyl-4 ,5,6, 7-tetrahydroindenyl, 4 , 7-dimethyl-4,5,6,7- tetrahydroindenyl , 2,4, 7-trimethyl-4 ,5,6, 7-tetra- hydroindenyl and fluorenyl. Catalyεt according to Claim 1, wherein in the cyclopentadienyl compound of the formula (I) the substituentε Q are chlorine atoms or methyl groups. Catalyst according to Claim 1, wherein in the organometallic aluminium compound of the formula (II) R 4 is a methyl or ethyl group. Catalyst according to one of Claims 1 to 7, wherein in the organometallic aluminium compound of the formula (II) R 6 iε hydrogen. Catalyεt according to Claim 8, wherein in the organometallic aluminium compound of the formula (II) R 4 is a methyl group and R 5 iε an alkyl group with a branched chain having a number of carbon atomε greater than 4. 10. Catalyst according to Claim 1, wherein the organometallic aluminium compound of the formula (II) iε tri- (2,4,4-trimethyl-pentyl) -aluminium. 11. Catalyεt for the polymerization of olefinε, comprising the product obtained from contacting the following componentε: (A) a cyclopentadienyl compound of the formula (I) ( 5 R 'x-m H 5-χ)R 2 . n (C 5 R 1 y . m H 5 . y ) „MQ 3 . n (I) in which M iε Ti, Zr or Hf, C 5 R' χ . m H 5.χ and C 5 R 1 y . m H 5 . y are cyclopentadiene ringε εubεtituted in the same way or different wayε, the εubεtituents R 1 which can be ident¬ ical or different are alkyl, alkenyl, aryl, alkylaryl or arylalkyl radicals which have from 1 to 20 carbon atoms and can alεo contain Si or Ge atoms, or Si(CH 3 ) 3 groups, or also two or four substituents R 1 of one and the same cyclopentadienyl group can form one or two rings having from 4 to 6 carbon atoms, R 2 is a group forming a bridge link between the two cyclopentadiene rings and is selected from CR 3 2 , C 2 R 3 4 , SiR 3 , Si 2 R 3 4 , GeR 3 2 , Ge 2 R 4 , R 3 2 SiCR 2 , NR 1 or PR 1 , with the substituents R 3 which can be identical or different being R 1 or hydrogen, or also two or four εubεtituents R 3 can form one or two ringε having from 3 to 6 carbon atomε, the εubstituents Q which can be identical or different are halogen, hydrogen, R 1 , OR 1 , SR 1 , NR 1 *-, or PR 1 -,, m can be 0 or 1, n can be 0 or 1, being l, if = 1, x is an inte¬ ger between (m+l) and 5, and y is an integer between m and 5; and (B) the product of the reaction between water and a mixture composed of: (Bl) 10-90 mol-% of an organometallic aluminium com¬ pound of the formula (II) : A1-(CH 2 -CR 4 R 5 R 6 ) 3.Z H Z (II) in which R 4 iε an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atomε, R 5 is an alkyl, alkenyl or alkylaryl group with a branched chain having from 3 to 10 carbon atomε, or R 4 and R 5 are fused together to form a cycle having from 4 to 6 carbon atoms, R 6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atomε, and z is 0 or 1; (B2) 10-90 mol-% of an organometallic aluminium com¬ pound of the formula (III) : A1R 3 3.W H W (III) in which the subεtituents R 3 which can be identical or different are alkyl, alkenyl or alkylaryl radicals which have from 1 to 10 carbon atoms and can also contain Si or Ge atoms, with the proviso that at least one of the subεtituentε R 3 iε other than a linear alkyl group, and w is 0 or 1, the com¬ pounds of the formula (II) defined above being excluded; the molar ratio between the organometallic aluminium compoundε and the water being between 1:1 and 100:1. 12. Proceεε for the polymerization of at leaεt one olefin of the formula CH-,=CHR, in which R is hydrogen or an alkyl, cycloalkyl or aryl radical having from 1 to 20 carbon atoms, compriεing the polymerization reaction of εaid olefins in the preεence of a catalyεt according to one of Claimε 1 to 11. 13. Process for the preparation of ethylene homopolymers, compriεing the polymerization reaction of ethylene in the preεence of a catalyεt according to one of Claims 1 to 11. 14. Procesε for the preparation of ethylene copolymers with one or more α-olefins of the formula CH 2 =CHR, where R is a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms or a cycloolefin, the said copolymers containing from 80 to 99 mol-% of units derived from ethylene and from 1 to 20 mol-% of units derived from alpha-olefins or cycloolefins and optionally minor proportions of units derived from a polyene, comprising the polymerization reaction of the ethylene as a mixture with the α-olefin(s) or cyclo¬ olefin(s) and optionally with the polyene in the pres¬ ence of a catalyst according to one of Claims 1 to 11. 15. Process for the preparation of elastomeric ethylene copolymerε with one or more alpha-olefinε of the for¬ mula CH- > =CHR, where R is an alkyl radical having from 1 to 10 carbon atoms, the said copolymerε optionally con¬ taining minor proportions of units derived from a polyene, comprising the polymerization reaction of the ethylene as a mixture with one or more alpha-olefins and optionally with minor proportions of a polyene in the presence of a catalyεt according to one of Claimε 1 to 11. 16. Process according to Claim 15, wherein the copolymers contain from 15 to 85 mol-% of ethylene and from 85 to 15 mol-% of an alpha-olefin selected from propylene, 1- butene and 4-methy1-1-pentene.

Inventors: GALIMBERTI MAURIZIO, GALIMBERTI, MAURIZIO
Applicants: GALIMBERTI MAURIZIO, MONTELL TECHNOLOGY COMPANY BV, GALIMBERTI, MAURIZIO, MONTELL TECHNOLOGY COMPANY B.V.
Application year: 1996
Main classification: C08F4
IPC codes: C08F4, C08F10, C08F210