NO309002B1 - Process for the preparation of a polymer by means of a catalyst in the form of a metal coordination complex on a support - Google Patents

Description

The present invention relates to a method for producing a polymer by bringing one or more addition polymerizable monomers under conditions of addition polymerization into contact with a catalyst placed on a carrier, and the system comprises a carrier, a catalyst and an activating cocatalyst.

The catalysts, in the form of a coordination complex with bound geometry, have unique properties due to the unique position of

the site where the active metal in the coordination complex with bound geometry is located. Under certain conditions, with the help of the catalysts it is possible to produce new olefin polymers with properties that have been unknown until now, due to the catalysts' unique ability for availability to polymerize α-olefins, diolefins, hindered vinylidene aliphatic monomers, vinylidene aromatic monomers and mixtures of these.

A large number of metal coordination complexes are known in the art, and include such complexes comprising monocyclopentadienyl groups and substituted monocyclopentadienyl groups. The present metal coordination complexes differ from those known previously in the art due to the fact that the metal is bonded to a delocalized substituted rc-bonded moiety in a manner that causes a bonded geometry around the metal. Preferably, the metal is bound to a cyclopentadienyl-, substituted cyclopentadienyl- or to a corresponding group both with an n5 and a bridge bond comprising other ligands of the metal. The complexes also preferably include metals which have useful catalytic properties.

Transition metal coordination complexes known as folded complexes are also previously known in the art. Such complexes are described in Organometallics 6, 232-241 (1987).

EP 277 004 describes certain bis(cyclopentadienyl) metal compounds which are formed by reaction between a bis(cyclopentadienyl) metal complex and salts of Brønstedt acids containing a non-coordinating compatible anion. The reference describes the fact that such complexes can be usefully used as catalysts in the polymerization of olefins. The aforementioned catalysts are not considered to be particularly effective olefin polymerization catalysts.

Previous attempts to prepare copolymers of vinylidene aromatic monomers and α-olefins, particularly copolymers of styrene and ethylene, have either failed to achieve significant incorporation of the vinylidene aromatic monomer or have otherwise yielded low molecular weight polymers. In Polymer Bulletin, 20, 237-241 (1988) a random copolymer of styrene and ethylene containing 1 mol% of styrene incorporated into the polymer is described. The described polymer yield was 8.3 x 10^<*> g polymer per micromoles of titanium used.

It has now been discovered that previously known addition polymerization catalysts are not capable of exhibiting high activity and polymerization of a high number of monomers because they lack bound geometry.

In one aspect, the present invention relates to a method where a metal coordination complex which has a bound geometry is used as a catalyst. More particularly, it concerns such coordination complexes which are usefully used in combination with activating cocatalyst compounds or mixtures of compounds to form a catalytic system which can be usefully used in the polymerization of addition polymerizable monomers, especially ethylenically unsaturated monomers.

In yet another aspect, the present invention relates to a process for the production of addition polymers, in particular homopolymers and copolymers of olefins, diolefins, hindered aliphatic vinyl monomers, vinylidene aromatic monomers and mixtures of the aforementioned, and the resulting polymeric products.

The catalyst is a metal coordination complex comprising a metal from group 3 (other than scandium), 4-10, or from the lanthanide group in the periodic table of the elements, and a delocalized rc-bonded part substituted with a force-inducing part, said complex having a bound geometry around the metal atom, so that the angle at the metal between the geometric center of gravity of the delocalized, substituted rc-bonded portion and the center of at least one remaining substituent is smaller than such an angle in a comparable complex which only differs in that said coercion-inducing substituent is replaced by hydrogen, and the invention further comprises that for such complexes comprising more than one delocalized, substituted 71-bonded moiety, only one of these for each metal atom in the complex is a cyclic, delocalized, substituted 71-bonded moiety.

Mentioned metal coordination complexes are hereinafter referred to as "metal coordination complexes for the invention".

The present invention consequently provides a method for the production of a polymer by bringing one or more addition polymerizable monomers under conditions of addition polymerization into contact with a catalyst on a carrier, the catalyst system comprising a carrier, a catalyst and an activating cocatalyst, which is characterized by the catalyst used comprises a metal complex of the formula

where

R' in each case is hydrogen or a moiety selected from alkyl, aryl, silyl,

germyl, cyano, halogen or a combination thereof with up to 20 non-hydrogen atoms, or where a pair of adjacent R' groups form a hydrocarbyl ring attached to the cyclopentadienyl moiety;

X in each case is hydride or a moiety selected from halogen, alkyl, aryl,

silyl, germyl, aryloxy, alkoxy, amide, siloxy or combinations thereof

with up to 20 non-hydrogen atoms;

Y is -O-, -S-, -NR<*-> or -PR<*->;

M is titanium, zirconium or hafnium; and

Z is SiR<*>2, CR<*>2, SiR<*>2SiR<*>2, CR<*>2CR<*>2, CR<*> = CR<*>,

CR<*>2SiR<*>2, GeR<*>2, BR<*>, or BR<*>2; where

R<*> in each case is hydrogen or a moiety selected from the group consisting of alkyl, aryl, silyl, halogenated alkyl, halogenated aryl and combinations thereof with up to 20 non-hydrogen atoms, or two or more R<*-> groups from Y, Z or both Y and Z form a closed ring system.

Catalysts that can be used for addition polymerizations comprise the following components: a) a metal coordination complex for the invention, preferably corresponding to formula I, and an activating cocatalyst. According to the present invention, a polymerization process is provided which comprises bringing one or more addition polymerizable monomers under addition polymerization conditions into contact with a catalyst, comprising a) a metal coordination complex for the invention, preferably corresponding to formula I, and an activating cocatalyst.

The complexes can be usefully used as catalysts for addition polymerization processes for the production of polymers in the form of molded objects, films for use as wrapping material, and foams for use in cushions, as well as for the modification of synthetic and naturally occurring resins. The complexes can also be used as catalysts for hydrogenations, catalytic cracking processes, as well as being used in other areas of industry.

When the expression "delocalized rc-bonded portion" is used, it means an unsaturated organic portion, such as e.g. such as include ethylenic or acetylenic functions, where the 71 electrons are given to the metal to form a bond. Examples include alkene, alkenyl, alkyne, alkynyl, silyl, polyene and polyenyl moieties, as well as unsaturated cyclic systems.

When using the expression "bound geometry" it is meant here that

the metal atom is forced to greater exposure of the active metal site due to one or more substituents on the delocalized rc-bonded moiety. Preferably, the delocalized 71-bonded moiety is a cyclopentadienyl or substituted cyclopentadienyl group, which forms part of a ring structure where the metal is both bonded to a nearby covalent moiety and is held in connection with the delocalized n-bonded moiety by means of r| <5->bindings. It should be understood that each of the respective bonds between the metal atom and the atoms which

occurring in the delocalized rc-bound portion need not be equivalent. That is to say, the metal can be symmetrically or asymmetrically n-bonded to the 7t-bonded portion.

The geometry of the active metal position is further defined as follows. The geometric center of gravity for the rc-bonded portion can be defined as the average of the associated X, Y and Z coordinates of the atomic centers that form the rc-bonded portion. The angle, 0, formed at the metal center between the geometric center of gravity of the 7t-bonded unit and each of the other ligands in the metal complex can be easily calculated using standard X-ray single-crystal diffraction techniques. Each of these angles can increase or decrease depending on the molecular structure of the metal complex with bound geometry. In complexes of this type where one or more of the angles, 9, are smaller than in a corresponding, comparison complex which differs only in that the coercive inducing substituent is replaced by hydrogen with bonded geometry for the purposes of the present invention. Preferably decreases

one or more of the above-mentioned angles, 0, by at least 5%, more preferably by 7.5%, in relation to the comparison complex. It is highly preferred that the average value of all bond angles, 0, is also smaller than in the comparison complex. Most preferred is the metal coordination complex with bound geometry in the form of a ring structure, i.e. that a coercive inducing substituent is part of a ring system comprising the metal.

Preferably, monocyclopentadienyl metal coordination complexes with metals from group 4 or from the lanthanides according to the present invention have bound geometry, so that the smallest angle, 0, is less than 115°, more preferably less than 110°, most preferably less than 105°.

The term "activating cocatalyst", as used herein, refers to a secondary component of the catalyst, which is capable of

causing the metal-containing complex to become effective as an addition polymerization catalyst, or alternatively, to balance the ionic charge of a catalytically activated moiety. Examples of the aforementioned activating cocatalyst for use herein include aluminum compounds with an Al-O bond, such as alkylaluminumoxanes, especially methylaluminumoxane; aluminum alkyls;

aluminum halides; aluminum alkyl halides; Lewis acids; ammonium salts; non-interfering oxidizing agents, ie silver salts, ferrocenions, etc. and mixtures of the foregoing.

Special methods for the production of compounds of the aluminumoxane type by bringing an aluminum alkyd compound into contact with an inorganic salt containing crystal water are described in US patent no. 4,542,119. In a particularly preferred embodiment, an aluminum alkyl compound is brought into contact with a regenerable substance containing water , like for example. hydrated alumina, silicon oxide or another substance. Another method for producing aluminum oxanes uses regenerable substances of the type described in EP 338 044.

Additional activating cocatalysts include compounds corresponding to the formula:

where

R in each case is C1-10 alkyl or arylalkyl;

X" is halogen; and

n is 1, 2 or 3.

Most preferably, such cocatalysts are trialkylaluminium compounds, especially triethylaluminium.

"Addition polymerizable monomers" include e.g. ethylenically unsaturated monomers, acetylenic compounds, conjugated or non-conjugated dienes, polyenes, carbon monoxide, etc. Preferred monomers include C2-io-α-olefins, especially ethylene, propylene, isobutylene, 1-butene, 1-hexene, 4-methyl -1-pentene and 1-octene. Other preferred monomers include styrene, halogen- or alkyl-substituted styrenes, vinyl chloride, acrylonitrile, methyl acrylate, methyl methacrylate, tetrafluoroethylene, methacrylonitrile, vinylidene chloride, vinylbenzocyclobutane and 1,4-hexadiene.

By the term "hindered aliphatic vinylidene compounds" is meant addition polymerizable vinylidene monomers corresponding to the formula:

where R" is a sterically bulky aliphatic substituent of up to 20 carbon atoms, G is independently in each case hydrogen or methyl, and G' is independently in each case hydrogen or methyl, or alternatively, G' and R" together form a ring system. By the term "sterically bulky" is meant that the monomer having this substituent is generally not capable of addition polymerization using standard Ziegler-Natta polymerization catalysts at a rate comparable to ethylene polymerizations. Preferred hindered aliphatic vinylidene compounds are monomers in which one of the carbon atoms which is ethylenically unsaturated is tertiary or quaternary substituted. Examples of such substituents include cyclic aliphatic groups, such as cyclohexane, cyclohexene, cyclooctene, or ring-shaped alkyl- or aryl-substituted derivatives thereof, tert-butyl, norbornyl, etc. Most preferred hindered aliphatic vinylidene compounds are the various isomeric vinyl ring-substituted derivatives of cyclohexene and substituted cyclohexenes, and 5-ethylidene-2-norbornene. Particularly suitable are 1-, 3- and 4-vinylcyclohexene.

The term "hindered vinylidene compounds" means addition polymerizable vinylidene monomers corresponding to the formula:

where R'" is R" or an aryl substituent of up to 20 carbon atoms, and G and G' are as previously defined. Hindered vinylidene compounds thus include e.g. in addition to hindered aliphatic vinylidene compounds also vinylidene aromatic monomers.

The term "vinylidene aromatic monomers" means addition polymerizable compounds corresponding to the formula:

where G independently in each case is hydrogen or methyl, and Ph is phenyl or a halogen or C 1-4 -alkyl substituted phenyl group. Preferred vinylidene aromatic monomers are monomers corresponding to the above formula wherein G

in each case is hydrogen. A most preferred vinylidene aromatic monomer is styrene.

The term "α-olefin" refers to ethylene and the C3-io-olefins with ethylenic unsaturation in the α-position. Preferred α-olefins are ethylene, propylene, 1-butene, isobutylene, 4-methyl-1-pentene, 1-hexene and 1-octene, and mixtures thereof.

All references to the periodic table of elements and groups in this system, as used herein, shall refer to the version of the periodic table published in the Handbook of Chemistry and Physics, CRC Press, 1987, which uses the IUPAC system of naming groups .

Preferred metal coordination complexes are complexes based on group 4 or on lanthanides. Further preferred complexes are those which comprise a delocalized t|<5->bonded group which is a cyclopentadienyl or substituted cyclopentadienyl group, which forms a ring structure with the metal atom. Preferred delocalized rc moieties are cyclopentadienyl, indenyl and fluorenyl groups and saturated derivatives thereof which form a ring structure with the metal atom. Each carbon atom of the cyclopentadienyl radical may be substituted or unsubstituted by the same radical or a different radical selected from the group consisting of hydrocarbyl radicals, substituted hydrocarbyl radicals, wherein one or more hydrogen atoms are replaced by a halogen atom, hydrocarbyl-substituted metalloid- radicals, where the metalloid is selected from group 14 in the periodic table of the elements, and halogen radicals.

In addition, two or more such substituents can together form a closed ring system. Suitable hydrocarbyl and substituted hydrocarbyl radicals, which may be substituted for at least one hydrogen atom in the cyclopentadienyl radical, will contain from 1 to 20 carbon atoms and include straight and branched chain alkyl radicals, cyclic hydrocarbon radicals, alkyl-substituted cyclic hydrocarbon radicals, aromatic radicals and alkyl- substituted aromatic radicals. Suitable organometalloid radicals include mono-, di- and tri-substituted organometalloid radicals from Group 14 elements, each of the hydrocarbyl groups containing from 1 to 20 carbon atoms. More particularly, suitable organometalloid radicals include trimethylsilyl, triethylsilyl, ethyldimethylsilyl, methyldiethylsilyl, phenyldimethylsilyl, methyldiphenylsilyl, triphenylsilyl, triphenylgermyl, trimethylgermyl and the like.

In the previously described formula I, suitable anionic ligand groups, X, are illustratively selected from the group consisting of hydride, halogen, alkyl, silyl, germyl, aryl, amide, aryloxy, alkoxy, phosphide, sulfide, acyl, pseudohalogens, such as . cyanide, azide, etc, acetylacetonate, etc, or a mixture of these.

As previously mentioned, the complexes preferably comprise structures that have changed or increased catalytic activity in the metal position when the complex is combined with a cocatalyst. In this regard, electron-donating substituents have been found to improve the catalytic properties of the complexes. That is to say, even if certain complexes do not have bound geometry, the same complex still exhibits catalytic properties, alone or in combination with

, activating substances.

It should be noted that while formula I and the following formulas indicate a cyclic structure for the catalysts, when Y is a neutral ligand donating two electrons, the bond between M and Y is more precisely referred to as a co-ordinate covalent bond. It should also be noted that the complex can occur as a dimer or as a higher oligomer.

Furthermore, it is preferred that at least one of R', Z or R<*> is an electron donating part. It is thus highly preferred that Y is a group containing nitrogen or phosphorus, and which corresponds to the formula -N(R"")- or -P(R"")-, where R"" is C to C to alkyl or aryl, ie an amide or phosphide group.

Preferred complex compounds are amidosilane or amidoalkanediyl compounds corresponding to the formula:

where

M is titanium, zirconium or hafnium, bonded with a bond type <35> to the cyclopentadienyl group;

R' is in each case hydrogen or a moiety selected from the group consisting of silyl, alkyl, aryl and combinations thereof having up to 10 carbon atoms or silicon atoms, or an adjacent pair of R' groups forming a hydrocarbyl ring which is joined to the cyclopentadienyl moiety;

E is silicon or carbon;

X is in each case hydride, halogen, alkyl, aryl, aryloxy or alkoxy with up to 10 carbon atoms;

m is 1 or 2.

The complexes can be prepared by contacting the metal reactant with a metal derivative from group 1 or a Grignard derivative of the cyclopentadienyl compound in a solvent and separating the salt by-product. Suitable solvents for the preparation of the metal complex are aliphatic or aromatic ligands, such as cyclohexane, methylcyclohexane, pentane, hexane, heptane, tetrahydrofuran, diethyl ether, C1-4 alkylethers of mono- or diethylene glycol, C1-4 alkylethers of mono- or dipropylene glycol, benzene, toluene , xylene, ethylbenzene, etc, or mixtures thereof.

In a preferred embodiment, the metal compound is MXn+i, i.e. M is at a lower oxidation state than in the corresponding compound MXn+2 and the oxidation state for M in the desired final complex. A non-interfering oxidizing agent can then be used to increase the metal's oxidation level. The oxidation is carried out exclusively by bringing the reactants into contact with each other using solvents and reaction conditions that are used for the production of the complex itself. By the term "non-interfering oxidizing agent" is meant a compound which has an oxidation potential which is sufficient to increase the metal's oxidation level without affecting the formation of the desired complex or the subsequent polymerization process. A particularly suitable non-interfering oxidizing agent is AgCl.

To facilitate the handling of the metal compounds used

in the present method and which corresponds to the formula MXn+2, it may be advantageous to first form a solid adduct of this compound when using

To facilitate the handling of the metal compounds used

in the present method and which corresponds to the formula MXn+2, it may be advantageous to first form a solid adduct of this compound using a suitable coordinating agent according to well-known techniques in the field. While titanium tetrachloride is a fuming liquid that is difficult to handle, one can e.g. first form an adduct of TiCU with an ether, a tertiary amine, a tertiary phosphine, or another basic non-protic compound. The resulting solids can be handled much more easily. A preferred coordinating adduct is tetrahydrofuran.

The reactions used to produce the metal complex can be carried out either heterogeneously or homogeneously. That is to say, the various reactants or the resulting products do not need to be soluble to a significant extent in the solvent mixture. In general, the reactants are brought into contact with each other under an inert atmosphere for a time from several minutes to several days. Stirring can be used if desired. The reaction temperature is generally from -90°C to 150°C, preferably from -20°C to 70°C.

Suitable catalysts for use in the process according to the present invention are prepared by combining the metal coordination compound and the activating cocatalyst compound in any order and in any suitable manner. Preferably, the ratio between the coordination complex and the cocatalyst is on a molar basis from 1:0.1 to 1:10,000. It would of course be preferable that the catalyst system can also be formed in situ if the system's components are added directly to the polymerization process using a suitable solvent or diluent, including condensed monomer, in said polymerization process. Suitable solvents include toluene, ethylbenzene, alkanes and mixtures thereof. In some cases, the catalyst can be isolated from the solution and stored in an inert atmosphere before use. The catalyst's components are sensitive to both moisture and oxygen, and should be handled and transferred in an inert atmosphere, such as nitrogen, argon or helium, or under vacuum.

The polymerization is usually carried out according to known methods for polymerizations according to Ziegler-Natta or Kaminsky-Sinn. The covering gas, such as nitrogen, argon, hydrogen, ethylene, etc. or under vacuum. Hydrogen can also be used to control molecular weight by forming chain ends, as is previously known from the field. The catalyst can be used as is, or it can be supported by a suitable support material such as alumina, MgCb or silicon oxide to provide a heterogeneous, supported catalyst. A solvent can be used if desired. Suitable solvents include toluene, ethylbenzene, and excess vinylidene aromatic or olefin monomer. The reaction can also be carried out in solution or under slurry conditions, in a suspension using a perfluorinated hydrocarbon or a similar liquid, in gas phase, that is using a fluidized bed reactor, or in a solid phase such as powder polymerization.

A catalytically effective amount of the present catalyst and cocatalyst is any amount that forms polymer with good results. Such quantities can be easily determined by routine testing by a skilled professional. Preferred amounts of catalyst and cocatalyst are sufficient to provide an equivalence ratio between addition polymerizable monomer and catalyst of from 1 x 10<10> : 1 to 100 : 1, preferably from 1 x 10<8> : 1 to 500 : 1, most preferred 1 x 106 : 1 to 1000 : 1. The cocatalyst is generally used in an amount to provide an equivalent ratio between cocatalyst and catalyst from 10,000 : 1 to 0.1 : 1, preferably from 1,000 : 1 to 1 : 1.

It should be understood that the metal complex can undergo various transformations or form intermediate products before and during the polymerization. It is thus possible to devise other preliminary products that can lead to the same catalytic materials as what is outlined here without deviating from the scope of the present invention.

The resulting polymeric product is recovered by filtration or by another suitable method. Additives and excipients can be incorporated into the polymers to provide desired characteristics. Suitable additives include pigments, UV stabilizers, antioxidants, emulsifiers, lubricants, plasticizers, photosensitizers, and mixtures thereof.

In the preparation of copolymers containing vinylidene aromatics or hindered aliphatic vinyl monomers, it is desirable that a comonomer which is a ct-olefin which is not particularly sterically hindered is also used. Without wishing to be bound by any particular theory of process, it is believed that this is because the active site is covered by the incorporation of the hindered vinyl compound, making it unlikely that another hindered vinyl compound could enter the polymerization as the next monomer in the sequence . After the incorporation of one or more olefins other than a hindered vinyl compound, the active site is once again able to accommodate a hindered vinyl monomer. However, on a limited basis, the vinylidene aromatic monomer or the sterically hindered vinyl monomer can enter the polymer chain in reverse order, i.e. resulting in two methylene groups between the substituted polymeric backbone portion.

Preferably, such polymers have a molecular weight greater than 13,000, more preferably greater than 20,000 and most preferably greater than 30,000. It is also preferred that such polymers have a melt index (b), ASTM D-1238 Method A, Condition E, of less than 125, more preferably from 0.01-100, and most preferably from 0.1 to 10.

As a result of the use of the previously mentioned catalyst system comprising a coordination complex with bound geometry, copolymers can be produced which enter relatively bulky or hindered monomers in an essentially random manner at low concentrations, and at higher concentrations according to a specific insertion logic. The copolymers of α-olefins, especially ethylene, and a hindered aliphatic vinylidene compound or vinylidene aromatic monomer can further be described as "pseudo-random". That is to say, the copolymers lack well-defined blocks of one or the other monomer, the respective monomers are however limited when it comes to joining according to certain rules.

These rules were derived from certain experimental details, which resulted from an analysis of the polymers. The polymers were analyzed by <13>C NMR spectroscopy at 130°C with a Varian VXR-300 spectrometer at 75.4 MHz. Samples of 200 to 250 mg of polymer were dissolved in 15 ml of warm o-dichlorobenzene/1,1,2,2-tetrachloroethane-d2 (approx. 70/30, vol.%) which contained approx. 0.05 M chromium(III)-tris(acetylacetonate) and a portion of the resulting solution was added to a 10 mm NMR tube. The following parameters and conditions were used: Spectrum width, 16,500 Hz; acquisition time 0.090 s; pulse width, 36°; delay, 1.0 s with tripping off during the delay; FT size 32K; number of scans, >30,000; increase in line width, 3Hz. The recorded spectra were referenced to tetrachloroethane-d2 (U73.77 ppm, TMS scale).

Without wishing to be bound by any particular theory, therefore, the results of the foregoing experimental procedure may indicate that a particularly salient feature of pseudo-random copolymers is the fact that all phenyl or bulky hindered groups substituted on the polymeric backbone are separated by of two or more methylene units. In other words, the polymers comprising a hindered monomer can be described by the following general formula (using styrene as an illustration of the hindered monomer):

where j, k and I are greater than or equal to 1.

To further explain the aforementioned experimental and theoretical results, and without wishing to be bound by any particular theory, it can be concluded that during the addition polymerization reaction using the present catalyst, if a hindered monomer is introduced into the growing polymer chain, the next monomer introduced is ethylene or a hindered monomer inserted in reverse or in a manner equivalent to "tail-to-tail". This is illustrated below for a hindered vinyl monomer, where M is the center of the metal catalyst, HG is a hindering group and P is the growing polymer chain:

During the polymerization reaction, ethylene can be introduced at any time. After an inverse or "tail-to-tail" hindered monomer is introduced, the next monomer must be ethylene, as introducing another hindered monomer at this location would place the hindering substituents closer together than the minimal separation described above . A consequence of these polymerization rules is that the catalyst in connection with the present invention does not homopolymerize styrene to any noticeable degree, while a mixture of ethylene and styrene quickly polymerizes, and can give copolymers with a high styrene content (up to 50 mol% styrene).

As a further illustration of the description of the copolymer of α-olefin and hindered monomer prepared according to the present invention, a computer model of the polymerization reaction was used to calculate the expected <13>C NMR spectrum of the polymeric product. The computer program used a random number generator to select either oc-olefin or hindered monomer to insert into a growing polymer chain, then calculated the number of each type of <13>C NMR signals resulting from this insertion. Polymers were computer generated by repeating this process for 10,000 or more monomer additions, and the resulting calculated <13>C NMR spectrum was compared to <13>C NMR spectra from the experiments performed for pseudo-random ethylene /styrene copolymers.

Computer simulations of the polymer and resulting <13>C NMR spectra of the calculated pseudo-random ethylene/styrene copolymers were performed using the constraint that if the styrene monomer was inserted into the growing polymer chain, the next polymer inserted must be ethylene or a styrene inserted in reverse or "tail-to-tail" fashion. An optimal fit between experimental and calculated spectra was achieved if approx. 15% of styrene insertions are in tail-to-tail fashion. It was found that in each case the observed and calculated spectra are in very good agreement.

Computer simulations of the polymer and resulting <13>C NMR spectra of completely random α-olefin/hindered monomer copolymers were then carried out without applying any constraints on the insertion of the hindered monomer. In other words, the hindered monomer was allowed to enter the growing polymer chain after a previously hindered monomer had been inserted if the random number generator chose the hindered monomer as the next monomer to be inserted. The calculated spectrum for these completely random copolymers was not in agreement with the obtained <13>C NMR spectrum.

Before the polymerization according to the present method, the monomers and solvents, if present, can be purified by vacuum distillation, and/or brought into contact with molecular sieves, silicon oxide or aluminum oxide to remove impurities. In addition, reactive removal styrene, Ci - C4 alkyl- or phenyl-, ring-substituted derivatives of styrene, such as oro-, meta- and para-methylstyrene, or mixtures thereof, ring-halogenated styrenes, vinylbenzocyclobutanes and divinylbenzene. A preferred vinylidene aromatic monomer is styrene.

In the polymerization of vinylidene aromatic monomers or hindered aliphatic vinylidene compounds and olefins, the monomers are preferably combined in such a ratio that a content of vinylidene aromatic monomer (or hindered aliphatic vinylidene compound) of at least 1.0 mol% is achieved in the resulting polymer, more preferably from 1.5 to less than 50 mol%, highly preferred 5.0 to 48 mol%, and most preferably from more than 8.0 and up to 47 mol%. Preferred operating conditions for such polymerization reactions are pressures from atmospheric pressure to 1000 atmospheres and temperatures from 30°C to 200°C. Polymerizations at temperatures above the autopolymerization temperature for the monomers may contain polymers with small amounts of homopolymeric polymerization products which are the result of polymerization of free radicals.

Certain polymers produced according to the present invention, in particular copolymers of ethylene and an α-olefin other than ethylene, are characterized by unique rheological properties. In particular, it has been found that the polymers (hereinafter called elastic polyethylenes or EIPEs) are less Newtonian than conventionally produced linear polyethylene resins with corresponding olefin content. The polymers also have a higher modulus of elasticity, especially at high melt indices, in comparison to such conventional polymers. This property makes the resin particularly useful for the formation of films, foams and for articles such as e.g. produced by injection molding. The above phenomenon is more specifically defined by reference to the table below, where the viscosity of the complex, rf, measured in Poise at 190°C, is listed as a function of the shear rate, co, measured in radians per second for a typical EIPE copolymer of ethylene and 1-octene in connection with the invention. The slope of the curve that appears when graphically presenting these data indicates that the melting is largely non-Newtonian. The values of ri<*> and co that have been used are: the curve that appears when graphically presenting these data indicates that the melting is highly non-Newtonian. The values of r|<*> and co used are: T|<*> CO T|<*> CO Tl<*> CO

1.962x10<5> 0.01000 3.320x10" 0.2512 1.088x10<4> 6.310 1.511x10<5> 0.01585 2.713x10<4> 0.3981 9.336x10<3>10.000 1.115x10<52512 0 2.293x10<4> 0.6310 7.964x10<3>15.850 8.292x10<4> 0.03981 1.966x10<4> 1.0000 6.752x10<3> 25.120 6.322x10<4> 0.06310 1.701x10<4 .5850 5.677x10<3> 39.810 4.920x10<4> 0.10000 1.464x10<4> 2.5120 4.721x10<3> 63.100 3.956x10<4> 0.15850 1.265x10<4> 3.9840x10<3 > 100,000

Listed below are the tan 8 values for the same EIPE polymer. This value is unnamed, and is calculated by dividing the viscosity modulus by the elasticity modulus. The values of tan 5 and co used in the graphic presentation are:

For improved performance in melt blowing applications, the tan 5 value is preferably from 0.1 to 3.0 for shear rates between 0.01 and 100 radians/second.

A further property of LiPE polymers is illustrated with reference to the table below. The modulus of elasticity in dyne/cm<2>, G', at 0.1 radians/sec, and 190°C for several ethylene/1-octene EIPE resins is plotted as a function of melt index. The numerical values for melt indices and modulus of elasticity are as follows:

It is clear that EIPE resins are characterized by high modulus of elasticity in the forge. In particular, EIPE resins have a melt index [(l2), ASTM D-1238 method A, condition E], of less than 200, preferably less than 125, most preferably less than 50, and a modulus of elasticity greater than 1000 dyne/cm<2 >, more preferably greater than 2000 dyn/cm<2>. All of the aforementioned rheological measurements have been carried out using standard techniques, such as those described in H.A. Barnes et al., Introduction to Rheology, Elsevier publishing, Inc., 1989. Specific gravity normally ranges from 0.85 to 0.97 g/ml, preferably from 0.89 to 0.97 g/ml. The molecular weight distributions (Mv/Mn) are greater than 2.0, preferably from 3.0 to 10.0. Typical melting points are from 50°C to 135°C.

Preferred polymers additionally show properties for homogeneous polymers as defined in US patent no. 3,645,992, i.e. ethylene copolymers with essentially random distribution of comonomers in a given molecule, and essentially the same ratio between ethylene and comonomers between the molecules. Polymers produced at higher polymerization temperatures, especially temperatures ethylene polymers, which makes it particularly suitable for use as a film and for injection molding.

In addition, it has surprisingly been found that the polymers comprising an olefin and a vinylidene aromatic monomer, especially ethylene and styrene, have elastomeric properties. Such polymers are thus uniquely suited for application to thermoplastic elastomers for impact modification of thermoplastic and thermosetting polymers, including bitumen, adhesives, elastomeric molded articles, etc.

The polymers may be modified by typical grafting, cross-linking, hydration, functionalization, or other reactions well known to those skilled in the art. Particularly with regard to the polymers having vinylidene aromatic functionality, vinylcyclohexene or 1,4-hexadiene functionality, these can be readily sulfonated or chlorinated to provide functionalized derivatives according to well-known techniques. In addition, the vinylcyclohexene-based polymers can be easily cross-linked by reaction of the unsaturated ring.

The polymers of the present invention, whether modified or not, can be mixed with synthetic or natural polymers to provide mixtures with desired properties. In particular polyethylene, ethylene/α-olefin copolymers, polypropylene, polystyrene, styrene/acrylonitrile copolymers (including rubber-modified derivatives thereof), syndiotactic polystyrene, polycarbonate, polyamide, aromatic polyester, polyisocyanate, polyurethane, polyacrylonitrile, silicone and polyphenylene oxide polymers can mixed with the polymeric materials according to the present invention. The polymeric modifier is used in amounts from 0.1 to 99% by weight, preferably 0.5 to 50% by weight.

In a highly preferred embodiment, the polymers containing ethylene and styrene are elastomeric, as defined in the definition of an elastomeric substance by ASTM Special Technical Bulletin No. 184 as a substance that can be stretched at room temperature to twice the length of the substance, and which will regain its original length when released.

In addition to the modification of synthetic thermoplastics, the present polymers are also usefully used as modifiers for asphalt or bitumen materials. The polymers of styrene/ethylene are preferably used in this way.

In addition to the modification of synthetic thermoplastics, the present polymers are also usefully used as modifiers for asphalt or bituminous materials. The polymers of styrene/ethylene are preferably used in this way.

The term "bitumen" can generally be defined as mixtures of hydrocarbons of natural or pyrogenic origin, or combinations of both, often accompanied by their non-metallic derivatives, which may be gaseous, liquid, semi-solid or solid, and which are usually soluble in carbon disulfide. As far as this invention is concerned, bitumen can be used in liquid, semi-solid or solid form. From a commercial point of view, bitumen is generally limited to asphalts and tars and pitches. A list of different bitumen materials that can be used in the present invention includes the following:

I. Asphalts

1. Petroleum asphalt

A. Direct-reduced asphalts

1. Reduction by atmospheric pressure or

reduced pressure

2. Precipitated using a solvent, such as propane

B. Thermal asphalts as residues from

cracking processes on petroleum materials

C. Air blown asphalts

1. Direct-blown

2. "Catalytic" blown

2. Natural asphalts

A. With mineral content below 5%

1. Asphaltites such as gilsonite, graphamite and

gloss pitch

2. Bermudez and other natural deposits

B. With mineral content above 5%

1. Stone asphalt

2. Trinidad and other natural deposits.

B. Coal tar pitch types, where reduction is through-

brought to softening point level 2. Residues from other pyrogenic distillates, such as from water gas, wood, peat, bone, shell, hard resin and fatty acid tars

Something that can easily be assessed by professionals is that the average molecular weight of the different bitumen types can vary over a large area, such as e.g. from 500 to 10,000.1 addition, the softening point of the different types of asphalt can also vary, such as from 10°C to 205°C.

Of the many types of asphalt that can be used, petroleum asphalt and natural types are desired, with petroleum being preferred. Of the petroleum asphalts, the thermal asphalts are preferred.

The amount of bitumen used in the materials preferably ranges from 65 to 99 parts by weight, with preferred amounts from 80 to 98 parts by weight.

After the invention has now been described, the following examples shall be given for further illustration. Unless otherwise stated, parts and percentages are parts by weight and percentages by weight.

Example 1

Preparation of (tert-butylamido)dimethyl(tetramethyl-r|5-cyclopentadienyl)silanetitanium dichloride

Preparation 1

a) (Chloro)(dimethyl)(tetramethylcyclopentadi-2,4-enyl)silane

To a solution of 21.5 g (167 mmol) of dimethyldichlorosilane in 150 ml of THF

cooled to -40°C, a solution of 8.00 g (55.6 mmol) of sodium 1,2,3,4-tetramethylcyclopentadienide in 80 ml of THF was slowly added. The reaction mixture was allowed to warm to room temperature and was stirred overnight. The solvent was removed and the residue was extracted with pentane and filtered. The pentane was removed under reduced pressure to give the product as a pale yellow oil. The yield was 10.50 g (88.0%). <1>H NMR (C6D6) U 2.89 (s, 1H), 1.91 (s, 6H),

1.71 (s, 6H), 0.14 (s, 6H); <13>C NMR (C 6 C 6 ) δ 137.8, 131.5, 56.6, 14.6, 11.4, 0.81.

b) (Tert-butylamino)(dimethyl)(tetramethylcyclopentadi-2,4-enyl)silane

A solution of 11.07 g (151 mmol) of t-butylamine in 20 ml of THF was added in

during 5 minutes to a solution of 13.00 g (60.5 mmol)

(chloro)(dimethyl)(tetramethylcyclopentadienyl)silane in 300 mL THF. A precipitate immediately formed. The slurry was stirred for 3 days, then the solvent was removed, the residue was extracted with pentane and filtered. The pentane was removed under reduced pressure to give the product as a pale yellow oil. The yield was 14.8 g (97.2%). MS: 251 1H NMR (C 6 D 6 ) δ 2.76 (s, 1H), 2.01 (s, 6H), 1.84 (s, 6H), 1.09 (s, 9H), 0.10 (s , 6H); <13>C NMR (C 6 D 6 ) δ 135.4, 133.2, 57.0, 49.3, 33.8, 15, 0, 11, 2, 1, 3.

c) Dilithium (tert-butylamido)(dimethyl)(tetramethylcyclopentadienyl)silane

To a solution of 3.000 g (11.98 mmol) of (tert-butylamino)(dimethyl)(tetra-methylcyclopentadienyl)silane in 100 ml of ether was slowly added 9.21 ml of 2.6 M (23.95 mmol) butyllithium in a solvent of mixed C6 alkanes. A white precipitate formed and the reaction mixture was stirred overnight, then filtered. The solid was washed several times with ether and then dried under reduced pressure to give the product as a white powder. The yield was 3.134 g (99.8%).

d) (Tert-butylamido)(dimethyl)(tetramethyl-T|<5->cyclopentadienyl)silantitanium dichloride

0.721 g (3.80 mmol) of TiCl 4 was added to 30 ml of deep-frozen (-196°C) THF. The mixture was allowed to warm to -78°C (dry ice bath). To the resulting yellow solution was slowly added a solution of 1.000 g (3.80 mmol) of dilithium (tert-butylamido)(dimethyl)(tetramethylcyclopentadienyl)silane in 30 mL of THF. The solution was allowed to warm to room temperature with stirring overnight. The solvent was removed from the resulting very dark solution. The residue was extracted with pentane and filtered. Cooling in a freezer caused

separation of an easily soluble dark red-brown material from a light yellow-green crystalline solid. The solid was filtered off and recrystallized from pentane to give the olive green product. The yield was 0.143 g (10.2%). <1>H NMR (C 6 D 6 ) δ 2.00 (s, 6H), 1.99 (s, 6H), 1.42 (s, 9H), 0.43 (s, 6H); <13>C NMR (C 6 D 6 ) δ 140.6, 137.9, 104.0, 62.1, 32.7, 16.1, 13.0, 5.4.

Preparation 2

In a glovebox, 4.0 mL of 2.0 M isopropyl magnesium chloride in diethyl ether was injected into a 100 mL flask. The ether was removed under reduced pressure, leaving a colorless oil. 20 ml of a 4:1 (volume) mixture of toluene and THF was added, and then 0.97 g of (tert-butylamido)(dimethyl)(tetramethylcyclopentadienyl)silane. The solution was heated to reflux temperature. After 8 - 10 hours, a white precipitate began to form. After refluxing for a total of 27 hours, the solution was cooled and the volatiles were removed under reduced pressure. The white solid residue was slurried in pentane and filtered to leave a white powder (1.23 g, 62% yield) of Me4C5SiMe2N-t-BuMg2Cl2(THF)2.

In the glove box, 0.50 g of TiCl3(THF)3 was suspended in 10 ml of THF. 0.69 g of solid Me4C5SiMe2N-t-BuMg2Cl2(THF)2 was added, resulting in a color change from pale blue to deep purple. After 15 minutes, 0.35 g of AgCl was added to the solution. The color immediately began to lighten until it was a pale greenish yellow. After VA hour, the THF was removed under reduced pressure, and a yellow-green solid remained. Toluene (20 mL) was added, the solution was filtered, and the toluene was removed under reduced pressure to leave a yellow-green microcrystalline solid, 0.51 g (quantitative yield). The identity of the product was confirmed to be (tert-butylamido)dimethyl(tetramethyl-r|<*->cyclopentadienyl)silantitanium dichloride by <1>H NMR (C6D6): U 1.992 (s), 1.986 (s), 1.414 (s), 0.414 (s).

Preparation 3

TiCl 4 , 0.72 g (3.80 mmol) was added to 35 ml deep-frozen THF (-196°C) in an Err flask. The mixture was heated to -78°C. A solution of 1.0 g (3.80 mmol) of dilithium(tert-butylamido)dimethyl(tetramethylcyclopentadienyl)silane in THF was slowly added. The solvent was removed to give a dark residue, which was extracted with pentane and filtered. The product (C5Me4(Me2SiN-t-Bu)TiCl2) was obtained as a dark greenish-yellow crystalline material after twice recrystallization from pentane at -35 to -40°C. The identity was confirmed by <13>C and <1>H NMR.

Preparation 4

In the glovebox, TiCl 3 (THF) 3 (2.0 g, 5.40 mmol) was suspended in 40 mL of THF. Dilithio (tert-butylamido)dimethyl(tetramethylcyclopentadienyl)silane (1.42 g, 5.39 mmol) was then added, which immediately resulted in the color becoming darker, eventually dark blue. After stirring for VA hour, AgCl (0.84 g, 5.86 mmol) was added. The color immediately began to lighten to a red/orange. After stirring for VA hour, the THF was removed under reduced pressure. Diethyl ether (50 mL) was added, the solution was filtered, and the volatiles were removed under reduced pressure. This gave a yield of 1.91 g of the product (tert-butylamido)dimethyl(tetramethyl-Ti*-cyclopentadienyl)silanetitanium dichloride. <1>H NMR (C 6 D 6 ): δ 1.992 (s), 1.987 (s), 1.415 (s), 0.415 (s).

Polymerization

Polymerization of a styrene/ethylene mixture was carried out by mixing 1.65ml of a 10% solution of MAO in toluene with a solution of 45ml toluene and 50ml styrene in a stainless steel container. 250 µl of a 0.010 M solution of (tert-butylamido)dimethyl(tetramethyl-r|<*->cyclopentadienyl)silanetitanium dichloride was added to 2.5 ml of toluene in a second container. Both containers were tightly closed, removed from the glove box and connected to a 600 ml stainless steel pressure vessel. The pressure vessel was evacuated and flushed with argon.

The styrene/toluene/MAO solution was added to the pressure vessel and heated to 89°C at an ethylene pressure of 620 kPa with stirring. At this point the catalyst solution was added and the pressure was increased to 1275 kPa and regulated between 1240 and 1275 kPa. The exothermic reaction caused the temperature to rise to 95°C. The temperature was lowered to 90°C, and was then kept between 90 and 92°C for the remainder of the reaction time. ~—

After 1.0 hour, the ethylene supply was stopped. The reaction mixture was vented to atmosphere, and cooled to 30°C, at which point methanol was added. The product was recovered, washed with methanol, and residual solvents were removed under reduced pressure at 120°C, resulting in 9.02 g of material. <13>C NMR analyzes of this material showed it to be a random copolymer of styrene (15.2% on a molar basis) and ethylene; there were no peaks attributable to polystyrene.

Example 2

Preparation of (tert-butylamido)dimethyl(tetramethyl-r|*-cyclopentadienyl)silanetitanium dichloride on a support material

0.100 g of dehydroxylated silica (-OH concentration, 1 mmol/g SiO 2 ) was slurried in 20 ml of mixed mixed C6-alkane solvent under a nitrogen atmosphere in a glove box, with stirring in a 50 ml Erlenmeyer flask. From this slurry, 1.0 ml was withdrawn by means of a syringe and combined with 1.10 ml of a 0.011 M toluene solution of (tert-butylamido)-dimethyl(tetramethyl-ri<*->cyclopentadienyl)silantitanium- dichloride in a 5 ml round bottom flask and stirred for 12 hours. After this time period, 6.7 ml of a 10%

(wt/wt) solution of methylaluminoxane (MAO) in toluene to the solution containing silica.

Polymerization

Polymerization was carried out by adding the above titanium/silica/MAO slurry under pressure in a 3 liter stainless steel pressure vessel containing 2 liters of mixed alkane solvent under an ethylene pressure of 3100 kPa, at 150°C for 10 minutes. The ethylene pressure was held constant and a mass flow meter measured the uptake of ethylene to be 26.7 g. The polymer solution was then removed from the pressure vessel and the polyethylene was recovered after drying under reduced pressure at 90°C overnight. The yield was 30.0 g.

Claims (7)

1. Process for the production of a polymer by bringing one or more addition polymerizable monomers under conditions of addition polymerization into contact with a catalyst on a carrier, the catalyst system comprising a carrier, a catalyst and an activating cocatalyst, characterized in that 1) the catalyst used comprises a metal complex with the formula where R' in each case is hydrogen or a moiety selected from alkyl, aryl, silyl, germyl, cyano, halogen or a combination thereof with up to 20 non-hydrogen atoms, or where a pair of adjacent R' groups forms a hydrocarbyl ring attached to the cyclopentadienyl moiety; X in each case is hydride or a moiety selected from halogen, alkyl, aryl, silyl, germyl, aryloxy, alkoxy, amide, siloxy or combinations thereof with up to 20 non-hydrogen atoms; Y is -O-, -S-, -NR<*-> or -PR<*->; M is titanium, zirconium or hafnium; and Z is SiR<*>2, CR<*>2, SiR<*>2SiR<*>2, CR<*>2CR<*>2, CR<*> = CR<*>, CR<*>2SiR<*>2, GeR<*>2, BR<*>, or BR<*>2; where R<*> in each case is hydrogen or a moiety selected from the group consisting of alkyl, aryl, silyl, halogenated alkyl, halogenated aryl and combinations thereof with up to 20 non-hydrogen atoms, or two or more R<*-> groups from Y, Z or both Y and Z form a closed ring system. 2. Method according to claim 1, characterized by atMertitan. 3. Method according to claim 1 or 2, characterized in that the cocatalyst is an aluminum alkyl, an aluminum halide, a Lewis acid or a non-interfering oxidizing agent. 4. Method according to claim 3, characterized in that the carrier is magnesium chloride, silicon oxide or aluminum oxide. 5. Method according to claim 3, characterized in that the addition polymerizable monomer is selected from ethylenically unsaturated monomers, acetylenic compounds, conjugated or non-conjugated dienes, and polyenes, the monomers having from 2 to 20 carbon atoms. 6. Method according to claim 4, characterized in that it is carried out under slurry conditions or in gas phase. 7. Method according to claim 3, characterized in that ethylene, propylene, isobutylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene or a mixture thereof is polymerised.