MXPA00005267A - Elastomeric propylene polymers - Google Patents

Abstract

A thermoplastic elastomer is provided comprising a branched olefin polymer having crystalline sidechains and an amorphous backbone wherein at least 90 mole percent of the sidechains are isotactic or syndiotactic polypropylene and at least 80 mole percent of the backbone is atactic polypropylene. Additionally, a process is provided for producing a thermoplastic elastomer composition comprising:a) contacting, in solution, at a temperature from 90°C to 120°C propylene monomers with a catalyst composition comprising a chiral, stereorigid transition metal catalyst compound capable of producing isotactic or syndiotactic polypropylene;b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst capable of producing atactic polypropylene;and c) recovering a branched olefin polymer.

Description

ELASTOMERIC PROPYLENE POLYMERS Field of the Invention The present invention relates to elastomeric propylene polymers incorporating macromers and a method for the preparation of branched polymers having atactic polypropylene core structures and isotactic or syndiotactic polypropylene side chains utilizing transition metal catalyst compounds. BACKGROUND OF THE INVENTION Thermoplastic elastomers have commonly been produced by forming tri-block and multi-block copolymers. These types of copolymers can be useful as thermoplastic elastomer compositions ("TPE") due to the presence of "soft" (elastomeric) blocks containing "hard" (crystallizable or glassy) blocks. Hard blocks join the polymer network together at typical usage temperatures. However, when heated above the melting temperature or the glass transition temperature of the hard block, the polymer flows easily exhibiting thermoplastic behavior. See, for example, G. Holden and N.R. Legge, Thermoplastic Elastomers: A Comprehensive Review, Oxford University Press (1987). The best commercially known class of TPE polymers are styrenic block copolymers (SBC), typically linear tri-block polymers such as styrene-isoprene-styrene and styrene-butadiene-styrene, the latter of which when hydrogenated becomes essentially styrene- (ethylene-butene) -styrene block copolymers. Radial and star branched copolymers of SBC are also well known. These copolymers are typically prepared by sequential anionic polymerization or by chemical coupling of linear di-block copolymers. The transition temperature to glass (Tg) of a typical SBC TPE is equal to or less than 80-90 ° C, thus presenting a limitation in the utility of these copolymers under conditions of higher temperature usage. See, "Structures and Properties of Block Polymers and Multiphase Polymer Systems: An Overview of Present Status and Future Potential," S.L. Aggarwal, Sixth Biennial Manchester Polymer Symposium (Manchester UMIST, March 1976). Polymerization by insertion, or coordination of olefins can economically provide more efficient means of providing copolymer products, both due to process efficiencies and differences in input costs. These TPE polymers useful from olefinically unsaturated monomers, such as ethylene and α-olefins with from 3 to 8 carbon atoms, have been developed and are well known. Examples include physical blends of thermoplastic olefins ("TPO") such as polypropylene with ethylene-propylene copolymers, and similar mixtures wherein the ethylene-propylene or the ethylene-propylene-diolefin phase is dynamically vulcanized to remain well dispersed, discrete soft-phase particles in a matrix of Polypropylene. See, N.R. Legge, "Thermoplastic elastomer categories: a comparison of physical properties", ELASTOMERICS, pages 14-20 (Sept. 1991), and references cited therein. The use of metallocene catalysts for olefin polymerization has led to additional contributions to the field. U.S. Patent No. 5,391,629 discloses thermoplastic elastomer composites comprising diminished linear polymers and blocks of ethylene and alpha-olefin monomers. Polymers having hard and soft segments are said to be possible with single-site metallocene catalysts that are capable of preparing both segments. Examples of linear thermoplastic elastomers having hard blocks of high density polyethylene or isotactic polypropylene and soft blocks of ethylene-propylene rubber are provided. The earlier Japanese publication H4-337308 (1992) describes what is said to be a polyolefin copolymer product made by polymerizing propylene first to form an isotactic polypropylene and then copolymerizing the polypropylene with ethylene and propylene, both polymerizations in the presence of an organic aluminum compound and a bisciclopentadie-nyl zirconium dihalide bridged with silicon. In addition, polypropylene block polymers have been produced that exhibit elastic properties. G. Natta, in an article entitled "Properties of Isotactic, Atactic, and Stereoblock Homopolymers, Random and Block Copolymers of a-Olefins" (Journal of Polymer Science, Vol. 34, pp. 531-549, 1959) reported that fractionating an elastomeric polypropylene from a mixture of polymers. The elastomeric properties were attributed to a stereoblock structure comprising alternating isotactic and atactic stereosequences. Similar compositions were described in U.S. Patent No. 4,335,225. More recently, the international publication WO 95/25757 (Waymouth et al.) Described a method for the synthesis of elastomeric stere-obloque olefin polymers using catalysts that can change their geometry (between a chiral geometry and an achiral geometry) on a scale of time that is slower than a monomer insertion speed, but is faster than the average time of a simple chain construction. The resulting polymers may have properties ranging from crystalline thermoplastics to thermoplastic elastomers to amorphous rubber elastomers depending on the type and structure of the ligand, as well as the polymerization conditions. SUMMARY OF THE INVENTION The present invention provides a thermoplastic elastomer comprising a novel polypropylene structure. The structure combines central atactic, amorphous polypropylene structures with isotactic or syndiotactic polypropylene side chains, low molecular weight, high melting point. This differs from the tri-block or multi-block thermoplastic elastomers in that the "hard" domain is mainly present only in the side chains. The resulting polymer is unique because the central structure has increased elasticity on the central structures having both hard and soft blocks. Also, the crystalline side chains result in reduced chain separation after loading against the standard atactic polypropylene. The thermoplastic elastomer of the present invention comprises a branched olefin polymer having crystalline side chains and an amorphous core structure wherein at least 90 mole percent of the side chains are isotactic or syndiotactic polypropylene and at least 80 mole percent of the Central structure is atactic polypropylene. Additionally, a process for producing a thermoplastic elastomer composition is provided which comprises: a) contacting, in solution, at a temperature of from about 90 ° C to about 120 ° C, propylene monomers with a catalyst composition comprising a chiral stereo-rigid transition metal catalyst compound, capable of producing isotactic or syndiotactic polypropylene; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst capable of producing atactic polypropylene; and c) recovering a branched olefin polymer. Detailed Description of the Invention Thermoplastic elastomers contain stereo-blocks of "hard" and "soft" material. In the present invention, stereo-blocks are achieved through the incorporation of isotactic or syndiotactic polypropylene of low molecular weight, with high melting point, into amorphous atactic polypropylene core structures. The resulting stereo-block polymers have branched blocks with different stereo configurations in branches and core structures compared to polymers with stereo-sequences in the prior art. Stereo-specific branches, very crystalline, form well-dispersed domains linked by amorphous central structures. Therefore, these branched block polypropylenes have increased elasticity compared to thermoplastic stereo block elastomers, although reduced chain spacing after loading as compared to atactic polypropylene. The thermoplastic elastomer compositions of this invention are composed of branched polymers wherein both the polymer backbone and the polymer side chains are derived from polymerized propylene under coordination or insertion conditions with organometallic activated transition metal catalyst compounds. The side chains are isotactic or syndiotactic polypropylene which exhibits crystalline, semi-crystalline or glassy properties suitable for hard phase domains according to how the art understands these terms. These side chains are attached to the polymeric core structure which is amorphous. The central structure is composed of atactic polypropylene and, optionally, one or more co-monomers. Preferably, the central structure is atactic polypropylene. These compositions are useful as, among other things, compatibilizers. As used herein, "isotactic polypropylene" is defined as polypropylene having at least 70 percent isotactic pentadas according to 13C nuclear magnetic resonance analysis. "Syndiotactic polypropylene" is defined as polypropylene having at least 70 percent syndiotactic pentads according to 13C nuclear magnetic resonance analysis. "Highly isotactic polypropylene" is defined as polypropylene that has at least 90 percent isotactic pentads according to analysis by 13C nuclear magnetic resonance. Preferably, the macromers of the present invention are highly isotactic. "Atactic polypropylene" is defined as polypropylene having approximately 30 percent less than combined isotactic and syndiotactic pentades according to 13C nuclear magnetic resonance analysis, preferably about 20 percent or less. The branched polymers of the present invention have crystalline side chains wherein at least 90 mole percent of the side chains are isotactic or syndiotactic polypropylene. Preferably, at least 95 mole percent of the side chains are isotactic polypropylene. More preferably, at least 98 mole percent of the side chains are isotactic polypropylene. More preferably, 100 mole percent of the side chains are isotactic polypropylene. The branched polymers of the present invention have an amorphous core structure wherein at least 80 mole percent of the core structure is atactic polypropylene. Preferably, at least 90 mole percent of the core structure is atactic polypropylene. More preferably, at least 95 mole percent of the core structure is atactic polypropylene. Still more preferably, 100 mole percent of the core structure is atactic polypropylene. The physical and mechanical properties of the branched block polymers can be controlled by regulating the size, the crystallinity and the amount of incorporated macromer. Side Chains of Macromer The side chains are polypropylene macromers, which can be prepared under solution polymerization conditions with suitable metallocene catalysts to prepare some of isotactic or syndiotactic polypropylene. A preferred reaction process for propylene macromers having high levels of terminal vinyl unsaturation is disclosed in pending U.S. patent application 60 / 067,783, filed on 12/12/97. The catalysts typically used are bridged, chiral or asymmetric, stereorigid metallocenes. See, for example, U.S. Patent No. 4,892,851, U.S. Patent No. 5,017,714, U.S. Patent No. 5,132,281, U.S. Patent No. 5,296,434, U.S. Pat. No. 5,278,264, U.S. Patent No. 5,304,614, U.S. Patent No. 5,510,502, WO-A- (PCT / US92 / 10066) WO-A-93/19103, EP-A2-0 577 581, EP-A1-0 578 838, and the academic literature "The Influence of Aromatic Substituents on the Polymerization Behavior of Bridged Zirconocene Catalysts", Spaleck, W., 'et al., Organometa-llics 1994, 13, 954-963, and "Ansa-Zirconocene Polymerization Catalysts with Annelated Ring Ligands-Effects on Catalytic Activity and Polymer Chain Lengths", Brinzinger, H., et al., Organometallics 1994, 13, 964-970, and. documents referred to in them. Preferably, the stereo-rigid transition metal catalyst compound used to produce the isotactic polypropylene macromers of the present invention are selected from the group consisting of bis (indenyl) zirconocenes or bridged hafnocenes. In a preferred embodiment, the transition metal catalyst compound is a bridged dimethylsilyl bis (indenyl) zirconocene or hafnocene. More preferably, the transition metal catalyst compound is dichloride or dimethyl dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium or hafnium. In another preferred embodiment, the transition metal catalyst is a bis (indenyl) hafnocene dimethylsilyl bridged such as dimethyl or dimethylsilyl bis (indenyl) hafnium dichloride. Preferably, the catalysts used to produce the syndiotactic polypropylene macromers of the present invention are those described in U.S. Patent Nos. 4,892,851, 5,155,080, and 5,132,381. The method for preparing propylene-based macromers having a high percentage of vinyl terminal bonds involves: a) contacting, in solution, propylene, optionally a minor amount of copolymerizable monomer, with a catalyst composition containing the metal catalyst compound activated transition, stereorigid at a temperature of approximately 90 ° C to approximately 120 ° C; and b) recovering isotactic or syndiotactic polypropylene chains having average number molecular weights from about 2,000 to about 50,000 Daltons.

Preferably, the solution comprises a hydrocarbon solvent such as toluene. Also, the propylene monomers are preferably contacted at a temperature from 95 ° C to 115 ° C. More preferably, a temperature of 100 ° C to 110 ° C is used. More preferably, the propylene monomers are contacted at a temperature from 105 ° C to 110 ° C. Reaction pressures may generally vary from atmospheric to 345 MPa, preferably up to 182 MPa. Reactions can be run batch or continuously. Conditions for the suitable slurry reactions may also be convenient and are similar to the conditions in solution, the polymerization typically being carried out in liquid propylene under pressures convenient thereto. The polypropylene macromers can have narrow or broad molecular weight distribution (Mw / Mn), for example, from 1.5 to 5, typically 1.7 to 3. Optionally, mixtures of side chains with different molecular weights can be used. The average number molecular weight (Mn) of the polypropylene macromers of the present invention typically range from more than or equal to 2,000 Daltons to less than approximately 50,000 Daltons, preferably less than 40,000 Daltons. Preferably, the average number molecular weight of the polypropylene macromers of the present invention is greater than or equal to 5,000 Daltons. Preferably, the macromers of the present invention are made using solution phase conditions. Preferred solvents for the solution phase reactions are selected based on the solubility, volatility of the polymer and safety / health considerations. Non-polar or aromatic alkanes are preferred. More preferably, the solvent is aromatic. More preferably, the solvent is toluene. Central Polyolefin Structure The polyolefin core structure of the present invention is composed of propylene monomers and, optionally, one or more co-monomers. In one embodiment of the present invention there are no co-monomers present in the polyolefin backbone, resulting in a polymer having atactic polypropylene backbone and isotactic or syndiotactic polypropylene side chains. In another embodiment of the present invention, one or more co-monomers are present in the core structure. Comonomers which are useful in the present invention include ethylene, α-olefins with 4 to 20 carbon atoms, and alkyl substituted analogs with lower carbon number (3 to 8 carbon atoms) of the cyclic olefins and styrenics. Other copolymerizable monomers include geminally disubstituted olefins such as isobutylene, cyclic olefins of 5 to 25 carbon atoms such as cyclopentene, norbornene and norbornenes substituted by alkyl and styrenic monomers such as styrene and alkyl substituted styrenes. The co-monomers are selected for use based on the desired properties of the polymer product and the metallocene employed will be selected for its ability to incorporate the desired amount of olefins. When co-monomers are used, they preferably comprise from 3 to 20 mole percent of the branched polyolefin composition. More preferably, the co-monomers comprise from 5 to 17 mole percent of the branched polyolefin composition. The mass of the core structure will typically comprise at least 40 weight percent of the total polymer mass, that of the core structure and of the side chains together, so that the core structure will typically have a nominal average molecular weight (MW). ) at least equal to or greater than approximately 100,000. The nominal term is used to indicate that the direct measurement of Mw of the central structure is impossible but the characterization of the copolymer product will exhibit M "measurements that correlate to a very high weight. approximate of the polymeric core structure including only the mer mono-olefin derivatives and the insertion fractions of the side chains. Catalysts Catalysts that are useful for producing the branched polyolefin of the present invention include all catalysts that are capable of producing atactic polypropylene and incorporating significant amounts of the isotactic or syndiotactic polypropylene macromers of the present invention. Preferably, metallocene catalysts are used. As used in the present "metallocene" it generally refers to compounds represented by the formula CpmMRnXq wherein Cp is a cyclopentadienyl ring which can be substituted, or derivative thereof which can be substituted, M is a transition metal of the Group 4, 5, or 6, for example, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, R is a hydrocarbyl group or hydrocarboxy group having from 1 to 20 carbon atoms, X is halogen, and, - = 1-3, n = 0-3, q = 0-3, and the sum of m + n + q is equal to the oxidation state of the transition metal. Methods for making and using metallocenes are well known in the art. For example, metallocenes are detailed in U.S. Patent Nos. 4,530,914; 4,542,199; 4,769,910; 4,808,561; 4,871,705; 4,933,403; 4,937,299; 5,017,714; 5,026,798; 5,057,475; 5,120,867; 5,278,119; 5,304,614; 5,324,800; 5,350,723; and 5,391,790. Preferably, the catalyst used to produce the branched polyolefin of the present invention is a monocyclopentadienyl transition metal compound, such as those described in U.S. Patent Nos. 5,504,169 and 5,539,056. These preferred compounds include: dimethylsilyl (tetramethylcyclopentadienyl) (cyclododecylamido) titanium dichloride, dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexyl-amido) titanium dichloride, dimethylsilyl (tetramethylcyclopentadienyl) (1-adamantylamido) titanium dichloride, dimethylsilyl (tetramethylcyclopentadienyl) dichloride (t -butylamido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) (s-butylamido) titanium dichloride, dimethylsilyl (tetramethylcyclopentadienyl) (n-butylamido) titanium dichloride, dimethylsilyl dichloride (tetramethylcyclopentadienyl) (exo-2-norbornylamido) titanium, diethylsilyl (tetramethylcyclopentadienyl) dichloride (cyclododecyl-amido) titanium, diethylsilyl (tetramethylcyclopentadienyl) (exo-2-norbornylamido) titanium dichloride, diethylsilyl (tetramethylcyclopentadienyl) (cyclohexyl-amido) titanium dichloride, diethylsilyl (tetramethylcyclopentadienyl) dichloride (1-adamantylamido) titanium, methylene dichloride (tetramethylcyclopentadienyl), (cyclododecyl-amido) titanium, methylene dichloride (tetramethylcyclo-pentadienyl) (exo-2-norbornylamido) titanium, methylene dichloride (tetramethylcyclopentadienyl) (cyclohexylamido) titanium, methylene dichloride (tetramethylcyclopentadienyl) (1-adamantylamido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) (cyclododecylamido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) dimethyl (exo-2-norbornylamido) titanium, dimethylsilyl dimethyl (tetramethylcyclopentadienyl) (cyclohexyl-amido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) (1-adamantylamido) titanium, dimethylsilyl (2,5-dimethylcyclopentadienyl) (cyclododecylamido) titanium dichloride, dimethylsilyl (2,5-dimethylcyclopentadienyl) dichloride (exo- 2-norbornilami-do) titanium, dimethylsilyl dichloride (2,5-dimethylcyclopentadienyl (cyclohexylamido) titanium, dimethylsilyl dichloride (2,5-dimethylcyclopentadienyl (1-adamantylamido) titanium, dimethylsilyl (3,4-dimethylcyclopentadienyl) (cyclododecylamido) titanium dichloride, dimethylsilyl (3,4-dimethylcyclopentadienyl) dichloride (exo-2-norbornylamino) titanium , dimethylsilyl (3,4-dimethylcyclopentadienyl) (cyclohexylamido) titanium dichloride, dimethylsilyl (3,4-dimethylcyclopentadienyl) dichloride (1-adamantylamido) titanium, dimethylsilyl (2-ethyl-5-methylcyclopentadienyl) (cyclododecylamido) titanium dichloride, dimethylsilyl (2-ethyl-5-methylcyclopentadienyl) (exo-2-norbornylamido) titanium dichloride, dimethylsilyl dichloride (2) -ethyl-5-methylcyclo-pentadienyl) (cyclohexylamido) titanium, dimethylsilyl (2-ethyl-5-methylcyclopentadienyl) (1-adamantylamido) titanium dichloride, dimethylsilyl (3-ethyl-4-methylcyclopentadienyl) dichloride (cyclododecylamido) titanium, dimethylsilyl (3-ethyl-4-methylcyclopenta-dienyl) (exo-2-norbornylamido) titanium dichloride, dimethylsilyl (3-ethyl-4-methylcyclopentadienyl) dichloride (cyclohexylamido) titanium, dimethylsilyl (3-ethyl-4-methylcyclopenta-dienyl) (1-adamantylamido) titanium, dimethylsilyl (2-ethyl-3-hexyl-5-methyl-4-octylcyclopentadienyl) dichloride (cyclododecyl-amido) titanium, dimethylsilyl (2-ethyl-3-hexyl-5-methyl-4-octylcyclopentadienyl) (exo-2-norbonylamido) titanium dichloride, dimethylsilyl (2-ethyl-3-hexyl-5- dichloride methyl-4-octylcyclopentadienyl) (cyclohexylated) titanium, dimethylsilyl (2-ethyl-3-hexyl-5-methyl-4-octylcyclopentadienyl) (1-adamantylamido) titanium, dimethylsilyl (2-tetrahydroindenyl) dichloride ( cyclododecylamido) titanium, dimethylsilyl (2-tetrahydroindenyl) (cyclohexylamido) titanium dichloride, dimethylsilyl (2-tetrahydroindenyl) (1-adamantylamido) titanium dichloride, dimethylsilyl (2-tetrahydroindenyl) (exo-2-norborni-lamido) titanium dichloride and similar. The most preferred species are: dimethylsilyl (tetramethylcyclopentadienyl) (cyclododecylamido) titanium dichloride, dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexyl-amido) titanium dichloride, dimethylsilyl (tetramethylcyclopentadienyl) l-adamantylamido) dichloride, dimethylsilyl (tetramethylcyclopentadienyl) dichloride (exo) -2-norbornylamido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) (cyclododecylamido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexyl-amido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) (1-adamantylamido) titanium, dimethylsilyl (tetramethylcyclopentadienyl) dimethyl (exo-2-norbornylamido) titanium. The terms "co-catalyst" and "activator" are used interchangeably herein and are defined as any compound or component that can activate a transition metal compound with a bulk ligand or a metallocene, as defined above. Alumoxane can be used as an activator. A variety of methods for preparing alumoxane, nonlimiting examples thereof are disclosed in US Nos. 4665208, 4952540, 5091352, 5206199, 5204419, 4874734, 4924018, 4908463, 4968827, 5308815, 5329032, 5248801, 5,235,081, 5,157,137, 5,103,031 and EP-A-0 561 476, EP-B1-0 279 586, EP-A-0 594-218 and WO 94/10180. It may be preferable to use a visually clear methylalumoxane. A nebulous or gelled alumoxane can be filtered to produce a clear solution or a clear alumoxane can be decanted from the nebulous solution. It is also within the scope of this invention to use neutral or ionic ionizing activators, or compounds such as tri (n-butyl) ammonium tetrakis (pentafluorophenyl) boron, which ionizes the neutral metallocene compound. These ionizing compounds may contain an active proton, or some other cation associated with but not coordinated or only loosely coordinated to the remaining ion of the ionizing compound. Combinations of activators are also contemplated by the invention, for example, alumoxane and ionizing activators in combinations, see for example, WO 94/07928. Descriptions of ionic catalysts for coordination polymerization comprising cations activated by noncoordinating anions metallocene appear in the early work in EP-A-0277003, EP-A-0,277,004 and Patent No. 5,198,401 US and WO-A-92/00333. These teach a preferred method of preparation wherein the metallocene (bisCp and monoCp) are protonated by an anion precursor so that an alkyl / hydride group is abstracted from a transition metal to make it both cationic and charge balanced by the anion not coordinator The term "non-coordinating anion" means an anion that either does not coordinate with said cation or that only coordinates weakly with the cation whereby it remains sufficiently labile to be displaced by a neutral Lewis base. The "compatible" noncoordinating anions are those that do not degrade to neutrality when the initially formed complex decomposes. In addition, the anion will not transfer an anionic substituent or fragment to the cation to cause it to form a four-coordinate neutral metallocene compound and a neutral by-product from the anion. The non-coordinating anions useful in accordance with this invention are those which are compatible, stabilize the metallocene cation in the sense of balancing its ionic charge in a +1 state, while retaining sufficient lability to allow displacement by a monomer ethylenically or acetylenically unsaturated during the polymerization. The use of ionizing ionic compounds that do not contain an active proton but capable of producing both the active metallocene cation and a noncoordinating anion is also known. See, for example, EP-A-0 426 637 and EP-A 0 573 403. A further method of making ionic catalysts uses ionizing anion precursors which are initially neutral Lewis acids but form the cation and the anion after the reaction of ionization with the metallocene compounds, for example the use of tris (pentafluorophenyl) boron. See EP-A-0 520 732. Ionic catalysts for addition polymerization can also be prepared by oxidation of the metal centers of transition metal compounds by anion precursors containing metal oxidizing groups together with the anion groups, see EP-A-0 495 375. When the metal ligands include halogen moieties (for example, bis-cyclopentadienyl dichloride zirconium) which are not capable of abstraction under standard conditions ionization can be converted via known alkylation reactions with compounds organometallics such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc. See EP-A-0 500 944 and EP-A1-0 570 982 for in situ processes describing the reaction of alkylaluminum compounds with substituted metallocene dihalo compounds before or with the addition of activating anionic compounds. Support Materials The metallocenes described herein are preferably supported using a porous particulate material, such as, for example, talc, inorganic oxides, inorganic chlorides and resinous materials such as polyolefin compounds or polymeric compounds. The most preferred support materials are porous inorganic oxide materials, which include those of the Periodic Table of the Metal Oxide Elements of Groups 2, 3, 4, 5, 13 or 14. Silicon oxide, aluminum oxide, Silicon oxide-aluminum oxide, and mixtures thereof are particularly preferred. Other inorganic oxides which can be used either alone or in combination with silicon oxide, aluminum oxide or silicon oxide-aluminum oxide are magnesium oxide, titanium oxide, zirconium oxide, and the like. Preferably the support material is porous silicon oxide having a surface area in the range of from about 10 to about 700 square meters / gram, a total pore volume in the range of from about 0.1 to about 4.0 cubic centimeters / gram and an average particle size in the range of from about 10 to about 500 microns. More preferably, the surface area is in the range of from about 50 to about 500 square meters / gram, the pore volume is in the range of from about 0.5 to about 3 '.5 cubic centimeters / gram and the average particle size it has the range of from about 20 to about 200 microns. More preferably, the surface area is in the range of from about 100 to about 400 square meters / gram, the pore volume is in the range of from about 0.8 to about 300 cubic centimeters / gram, and the average particle size is in the range of from about 30 to about 100 microns. The average pore size of typical porous support materials is in the range of from about 10 to about 1000 Á. Preferably, a support material is used having an average pore diameter of from about 50 to about 500 A, and more preferably from about 75 to about 350 A. It may be particularly desirable to dehydrate the silicon oxide at a temperature of from about 100 ° C to approximately 800 ° C from anywhere from about 3 to about 24 hours. The metallocenes, the activator and the support material can be combined in any way. Suitable support techniques are described in U.S. Patent Nos. 4,808,561 and 4,701,432. Preferably the metallocenes and the activator are combined and their reaction product is supported on the porous support material as described in U.S. Patent No. 5,240,894 and WO 94/28034, WO 96/00243, and WO 96/00245 . Alternatively, the metallocenes can be preactivated separately and then combined with the support material either separately or together. If the metallocenes are supported separately, preferably then, they are dried and then combined as a powder prior to their use in the polymerization. Regardless of whether the metallocene and the activator are contacted separately or if the metallocene and the activator are combined at one time, the total volume of the reaction solution applied to the porous support is preferably less than 4 times the total pore volume of the porous support, more preferably less than about 3 times the total pore volume of the porous support and even more preferably in the range of from more than about 1 to less than about 2.5 times the total pore volume of the porous support. Methods for measuring the total pore volume of the porous support are well known in the art. The preferred method is described in volume 1, Experimental Methods in Catalyst Research, Academic Press, 1968, pages 67-96. Methods of supporting ionic catalyst comprising metallocene cations and non-coordinating anions are described in WO 91/09882, WO 94/03506, WO 96/04319 and U.S. Patent No. 5,643,847. The methods generally comprise either physical adsorption on traditional or inorganic polymeric supports that have been highly dehydrated and dehydroxylated, or using neutral anion precursors that are Lewis acids strong enough to activate the hydroxy groups retained in silicon oxide containing oxide supports. inorganic so that the Lewis acid becomes covalently bound and the hydrogen of the hydroxy group is available to protonate the metallocene compounds. The supported catalyst system can be used directly in the polymerization or the catalyst system can be prepolymerized using methods well known in the art. For details regarding prepolymerization, see U.S. Patent Nos. 4,923,833 and 4,921,825, EP 0 279 863 and EP 0 354 893. Polymerization Processes The branched polyolefin of the present invention can be produced using the catalysts described above in any process that includes gas phase, slurry or solution or high pressure autoclave processes. (As used herein, unless differentiated, "polymerization" includes copolymerization and "monomers" includes co-monomer). Additionally, combinations of the above reactor types in multiple reactors, in series and / or multiple reaction conditions and / or multiple catalyst configurations are explicitly intended. Preferably, a gas or slurry phase process is used, more preferably a liquid propylene polymerization by volume process is used. In the preferred embodiment, the invention is directed toward liquid polymerization and copolymerization by volume of propylene in slurry or gas phase polymerization processes, particularly a slurry polymerization process. Another embodiment involves copolymerization reactions of propylene with one or more co-monomers. These co-monomers include alpha-olefin monomers having from 4 to 20 carbon atoms, preferably from 4 to 12 carbon atoms, for example comonomers of ethylene alphaolefin, butene-1, pentene-1,4-methylpentene-1, hexene -1, octeno-1, decene-1. Other suitable co-monomers include geminally disubstituted monomers, cyclic olefins of 5 to 25 carbon atoms such as cyclopentene or norbornene, styrenic olefins such as styrene, and analogs substituted by alkyl with a lower carbon number (from 3 to 8 carbon atoms). ) of cyclic olefins - and styrenics. In addition, co-monomers such as polar vinyl, diolefins such as dienes, for example, 1,3-butadiene, 1,4-hexadiene, norbornadiene or vinylnorbornene, acetylene and aldehyde monomers are convenient. Typically in a gas phase polymerization process a continuous cycle is employed wherein a part of the cycle of a reactor, a cyclization gas stream, otherwise known as a recycle stream or fluidization medium, is heated in the reactor by the heat of the polymerization. The recycle stream usually contains one or more monomers continuously cycled through a fluidized bed in the presence of a catalyst, under reactive conditions. This heat is removed in another part of the cycle by a cooling system external to the reactor. The recycle stream is removed from the fluidized bed and recycled back into the reactor. Simultaneously, the polymer product is removed from the reactor and fresh or new monomer is added to replace the polymerized monomer. (See, for example, U.S. Patent Nos. 4,543,399; 4,588,790; 5,028,670; 5,352,749; 5,405,922, and 5,436,304). A slurry polymerization process generally uses pressures in the range of from about 1 to about 500 atmospheres or even higher and temperatures in the range of -60 ° C to about 280 ° C. In a slurry polymerization, a suspension of particulate polymer, solid, is formed in a liquid or supercritical polymerization medium to which propylene and co-monomers and often hydrogen are added together with the catalyst. The liquid used in the polymerization medium can be, for example, an alkane or a cycloalkane. The medium employed should be liquid under polymerization conditions and relatively inert such as hexane and isobutane. In the preferred embodiment, the propylene serves as the polymerization diluent and the polymerization is carried out using a pressure of from about 200 kPa to about 7,000 kPa at a temperature in the range of from about 50 ° C to about 120 ° C. The time periods for each stage will depend on the catalyst system, the co-monomer and the reaction conditions. In general, the propylene should be homopolymerized for a period of time sufficient to produce a composition having from about 10 to about 90 weight percent homopolymer based on the total weight of the polymer, preferably from about 20 to about 80 percent by weight. percent by weight, even more preferably from about 30 to about 70 weight percent homopolymer based on the total weight of the polymer. The polymerization can be carried out in batch mode or in continuous mode and the entire polymerization can be carried out in a reactor or, preferably, the polymerization can be carried out in a series of reactors. If serial reactors are used, then the co-monomer can be added to any reactor in the series, however, preferably, the co-monomer is added to the second or subsequent reactor. In a preferred embodiment, the polymerization of the present invention is carried out in a series of reactors. In the first reactor, the stereospecific polypropylene macromers of the present invention are formed by reacting propylene monomers, and optionally other co-monomers, with at least one first transition metal olefin polymerization catalyst capable of preparing copolymers of propylene that have more than 50 percent unsaturation of chain end group. In the second reactor, the macromers are polymerized with propylene monomers, and optionally other co-monomers, in the presence of at least one second transition metal olefin polymerization catalyst capable of incorporating the propylene homopolymer or the side chains of copolymers in the branched olefin copolymer to form the branched olefin of the present invention. Additionally the branched polyolefin composition of the invention can be prepared directly from selected olefins concurrently in the presence of a mixed catalyst system comprising at least a first transition metal olefin polymerization catalyst capable of preparing propylene copolymers having more than 50 percent unsaturation of chain end group and at least one second transition metal olefin polymerization catalyst capable of incorporating the side chains of homopolymer or propylene copolymer into the branched olefin copolymer. This in situ method can be practiced by any method that allows both the preparation of isotactic or syndiotactic polypropylene macromers having crystalline, semi-crystalline or glassy properties and the copolymerization of the macromers with polypropylene and other comonomers so that a branched copolymer is prepared. Gas phase processes, slurry and solution can be used under conditions of temperature and pressure known to be useful in these processes. Hydrogen can be added to the polymerization system as a molecular weight regulator in the first and / or subsequent reactors depending on the particular properties of the desired product and the specific metallocenes used. When using metallocenes having different hydrogen responses, the addition of hydrogen will affect the molecular weight distribution of the polymer product according to the above. A preferred product form is to make the comonomer present in the high molecular weight species of the total polymer composition to provide a favorable balance of good film stretchability without breakage, coupled with low extractables, low cloudiness and good moisture barrier in the film. According to this in this preferred case, the same or lower levels of hydrogen are used during the copolymerization than are used during the polymerization in the second or subsequent reactor. For both the polypropylene macromer product and the branched polyolefin preparation, it is known that many methods and permutations are possible in the order of addition of the macromer and monomer species to the reactor, some more advantageous than others. For example, it is well known in the art that the preactivation of the metallocene with alumoxane prior to addition to a continuous solution phase reactor produces higher activities than the continuous addition of metallocene and activator in two separate streams. In addition, it may be advantageous to control the prior contact time to maximize the effectiveness of the catalyst, for example, by preventing excessive aging of the activated catalyst composition.

It is preferable to use isotactic or syndiotactic polypropylene macromers so that they are properly functionalized or copolymerized before being prepared. Very reactive vinyl groups appear to be susceptible to side-product reactions with adventitious impurities and, even, dimerization or addition reactions with other polymer chains containing unsaturated groups. Thus, maintaining in an inert, fresh environment after preparation and subsequent appropriate use will optimize the effectiveness of the use of the polypropylene macromer product. A continuous process using series reactors, or parallel reactors, will thus be effective, the polypropylene macromer product being prepared in one and continuously introduced in the other. Industrial Utility The thermoplastic elastomer compositions according to the invention will have use in a variety of applications where other thermoplastic elastomer compositions have found use. These uses include, but are not limited to, those known for styrene block copolymers, for example, copolymers of styrene-isoprene-styrene and styrene-butadiene-styrene, and their hydrogenated analogs. These include a variety of uses such as central structure polymers in adhesive compositions and molded articles. The compositions of the invention will also be convenient as compatibilizing compounds for polyolefin blends.

Additionally, due to the inherent tensile strength, elasticity, and ease of blending processing, extruded films, coating and packing compositions comprising the thermoplastic elastomer compositions of the invention, optionally modified with conventional additives and can be prepared. adjuvants In addition, in view of the preferred preparation processes using insertion polymerization of readily available olefins, the thermoplastic elastomer compositions of the invention can be prepared with low cost petrochemical inputs, under low energy input conditions, (in comparison to either with low temperature anionic polymerization or with multiple step mixing processing conditions where vulcanization is needed to achieve morphologies of discrete thermoplastic elastomers). In order that the invention may be more easily understood, reference is made to the following examples, which are intended to illustrate the invention but not to limit the scope thereof. EXAMPLES General All polymerizations were performed in a 2 liter Zipperclave reactor equipped with a water jacket for temperature control. The liquids were measured in the reactor using calibrated optical glasses. High purity toluene (greater than 99.5 percent) was purified by first passing it through basic aluminum oxide activated at high temperature under nitrogen, followed by molecular sieve activated at high temperature under nitrogen. The propylene was purified by passing it through activated basic aluminum oxide and molecular sieves. Methyl alumoxane (MAO, 10 percent in toluene) was received from Albemarle Inc. in stainless steel cylinders, divided into 1 liter glass containers, and stored in a laboratory glove box at room temperature. The propylene was measured in the reactor through a calibrated container. To ensure that the reaction medium was well mixed, a flat paddle stirrer at 750 rpm was used. Reactor Preparation The reactor was first cleaned by heating to 150 ° C in toluene to dissolve any polymer residue, then cooled and drained. Then, the reactor was heated using a water jacket at 110 ° C and the reactor was purged with flowing nitrogen for a period of about 30 minutes. Prior to the reaction, the reactor was further purged using 3 cycles of nitrogen pressurization / venting (at 7 kg / cm 2). Cycling served two purposes: (1) to thoroughly penetrate all dead ends such as pressure gauges to purge fugitive contaminants and (2) test reactor pressure.

Catalysts All the catalyst preparations were carried out in an inert atmosphere with a content of less than 1.5 ppm of water. The catalyst systems used in the synthesis of the isotactic polypropylene macromer was dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium dichloride. The dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium dichloride was activated with MAO. To maximize the solubility of the metallocenes, toluene was used as a solvent. The catalyst was added to a stainless steel tube by pipette and transferred to the reactor. Dimethylsilyl (tetramethylcyclopentadienyl) (cycloleadecylamido) titanium dichloride was used to assemble the branched polyolefin and was made according to the examples in U.S. Patent No. 5,057,475. Example 1 The synthesis of polypropylene macromer was carried out in a 2 liter autoclave reactor. The reactor was charged with toluene (1 liter), propylene (150 milliliters), and tri-isobutylaluminum (2.0 milliliters of IM solution in toluene). The reactor was heated to 105 ° C and equilibrated for 5 minutes. Then 2 milligrams of dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium dichloride and 1 milliliter of MAO (10 weight percent in toluene) were injected using a catalyst tube. After 15 minutes, the reactor was cooled to 25 ° C and vented. Methanol (500 milliliters) was added to the polymer solution to precipitate the polymer. The polymer was collected by filtration, and dried in a vacuum oven for 12 hours. The polymer product had an Mn of 15,700. The proportion of vinyl groups of total olefin groups in the polymer product was 0.85. Example 2 A 2 liter reactor was charged with toluene (1 liter) and 15 grams of the polypropylene macromer of Example 1. The reactor was heated at 100 ° C for 20 minutes to dissolve the macromer. The reactor was cooled to 30 ° C and 150 milliliters of propylene and 2 milliliters of MAO (10 weight percent in toluene) were added. The reactor was heated to 60 ° C and equilibrated for 5 minutes. Then 5 milligrams of dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexadecylamide) titanium dichloride in 5 milliliters of toluene and 2 milliliters of MAO (10 weight percent in toluene) were injected using a catalyst tube. After 60 minutes, the reactor was cooled to 30 ° C and vented. The polymer was precipitated by the addition of isopropanol (1 liter), and collected by filtration. The final dryer was made in a vacuum oven at 70 ° C for 12 hours to produce a white elastic solid. Production: 71 grams. Example 3 A 2 liter reactor was charged with toluene (1 liter) and 20 grams of the polypropylene macromer of Example 1. The reactor was heated at 100 ° C for 20 minutes to dissolve the macromer. The reactor was cooled to 30 ° C and 150 milliliters of propylene and 2 milliliters of MAO (10 weight percent in toluene) were added. The reactor was heated to 60 ° C and equilibrated for 5 minutes. Then 6 milligrams of dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexadecylamide) titanium dichloride in 5 milliliters of toluene and 2 milliliters of MAO (10 weight percent in toluene) were injected using a catalyst tube. After 60 minutes, the reactor was cooled to 30 ° C and vented. The polymer was precipitated by the addition of isopropanol (1 liter), and collected by filtration. The final drying was done in a vacuum oven at 70 ° C for 12 hours to produce a white elastic solid. Production: 63 grams. Example 4 A 2 liter reactor was charged with toluene (1 liter) and 20 grams of the polypropylene macromer of Example 1. The reactor was heated at 100 ° C for 20 minutes to dissolve the macromer. The reactor was cooled to 30 ° C and 150 milligrams of propylene and 2 milliliters of MAO (10 weight percent in toluene) were added. The reactor was heated to 60 ° C and equilibrated for 5 minutes. Then 4 milligrams of dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexadecylamide) activated titanium dichloride was injected into 5 milliliters of toluene and 2 milliliters of MAO (10 weight percent in toluene) using a catalyst tube. After 60 minutes, the reactor was cooled to 30 ° C and vented. The polymer was precipitated by the addition of isopropanol (1 liter), and collected by filtration. The final drying was done in a vacuum oven at 70 ° C for 12 hours to produce a white elastic solid. Production: 53 grams. Example 5 A 2 liter reactor was charged with toluene (1 liter) and 20 grams of the polypropylene macromer of Example 1. The reactor was heated at 100 ° C for 20 minutes to dissolve the macromer. The reactor was cooled to 30 ° C and 150 milligrams of propylene and 2 milliliters of MAO (10 weight percent in toluene) were added in. The reactor was heated to 60 ° C and equilibrated for 5 minutes. milligrams of dimethylsilyl (tetramethylcyclopentadienyl) (cyclohexadecylamide) activated titanium in 5 milliliters of toluene and 1 milliliter of MAO (10 weight percent in toluene) using a catalyst tube After 30 minutes, the reactor was cooled to 30 The polymer was precipitated by the addition of isopropanol (1 liter), and was collected by filtration The final drying was done in a vacuum oven at 70 ° C for 12 hours to produce a white elastic solid. Production: 37 grams Comparative Example 6 A comparative example was carried out to compare a mixture of atactic polypropylene and isotactic polypropylene macromer with the branched olefin polymer of the present invention. combining the atactic polypropylene and the isotactic polypropylene macromer produced in Example 1. The atactic polypropylene was produced by charging a 2 liter reactor with toluene '(1 liter) and adding 150 milliliters of propylene and 2 milliliters of MAO (10 percent by weight). weight in toluene). The reactor was heated to 60 ° C and equilibrated for 5 minutes. Then, 4 milligrams of dimethylsilyl (tetramethylcyclopentadienyl) (ciclecha-dadecylamide) titanium activated dichloride was injected into 5 milliliters of toluene and 2 milliliters of MAO (10 weight percent in toluene) using a catalyst tube. After 60 minutes, the reactor was cooled to 30 ° C and vented. The polymer was precipitated by the addition of isopropanol (1 liter), and collected by filtration. The final drying was done in a vacuum oven at 70 ° C for 12. Production: 48 grams. The atactic polypropylene product had an Mn of 184,500, and Mw of 495,100 and a polydispersity of 2.68. One flask was charged with toluene (500 milliliters), atactic polypropylene (12 grams), and the polypropylene macromer of example 1 (3 grams). The flask was connected to a condenser and heated to 110 ° C under nitrogen with mechanical stirring. When the polymer was completely dissolved, the flask was cooled to 25 ° C and methanol (500 liters) was added. The precipitated polymer was collected by filtration, and dried in a vacuum oven at 60 ° C for 12 hours to produce a white elastic solid. Production: 14.5 grams. Characterization of the Product Some general characterization data of the polymers made in Examples 2 to 5 and Comparative Example 6 are listed in Table 1. The glass transition temperature (Tg) and the melting point (Tm) of the Samples of the polymer product were determined on a Differential Scanning Calorimeter DSC 2910 (TA Instruments). The reported melting points were recorded at the second melt with a temperature ramp of 5 ° C / minute. He . percentage of propylene macromer in the polymer samples is calculated by mass balance. Table 1 Summary of Physical Properties The polymer product of Examples 2-5 was analyzed by gel permeation chromatography using a Waters 150C high temperature system equipped with a DRI detector, Showdex AT-806MS column and operating at a system temperature of 145 ° C. The solvent used was 1, 2, 4-trichlorobenzene, from which solutions of polymer samples of 1.5 milligrams / milliliter of concentration for injection were prepared. The flow rate of the total solvent was 1 milliliter / minute and the size of the injection was 300 microliters. After elution of the polymer samples, the resulting chromatograms were analyzed using the Waters Expert Fuse program to calculate the molecular weight distribution and one or more averages of Mn, Mw and Mz. The results are listed in Table 2. Table 2 GPC molecular weight and weight summary The tensile strength behavior of the thermoplastic elastomers produced in Examples 2 to 5 and Comparative Example 6 was studied with mechanical testing machines. The polypropylene samples were press molded into specimens 15 millimeters long, 6 millimeters wide and 0.7 millimeters thick in dog bone shapes at 180 ° C. Samples were subjected to stress imposed by an Instron ™ 4505 machine at a uniaxial extension rate of 6 inches per minute to the breaking point. The elastic property was characterized with an Instron ™ 4505 machine. Samples were lengthened to 300 percent at an expansion speed of 15.24 centimeters per minute. The tension was released immediately and the recovery was measured after 10 minutes. The results are presented in Table 3. Table 3 Summary of Mechanical Property Although certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the processes and products described therein can be made without departing from the scope of the invention, which is defined in the appended claims.

Claims (24)

1. CLAIMS 1. A thermoplastic elastomer composition, comprising a branched olefin polymer having crystalline side chains and an amorphous backbone, wherein said side chains are at least 90% molar of isotactic or syndiotactic polypropylene and said backbone is at least 80% molar of atactic polypropylene. The composition of claim 1, wherein said side chains are at least 95 mol% isotactic polypropylene and said backbone is at least 90 mol% atactic polypropylene. The composition of claim 1, wherein said side chains are at least 98 mol% isotactic polypropylene and said backbone is at least 95 mol% atactic polypropylene. The composition of claim 1, further comprising one or more co-monomers selected from the group consisting of ethylene, C4-C20 alpha-olefins, geminally disubstituted monomers, C5-C25 cyclic olefins, styrenic olefins, and substituted alkyl analogs of low carbon number (C3-C8) of the cyclic and styrenic olefins. The composition of claim 4, wherein said one or more co-monomers comprise from 3 to 20 mole% of said polyolefin composition. The composition of claim 4, wherein said one or more co-monomers comprise from 3 to 20 mole% of said polyolefin composition. 7. A composition of. thermoplastic elastomer, produced by the process comprising: a) contacting, in solution, at a temperature of 90 to 120 * C, propylene monomers with a catalyst composition comprising a stereo-rigid transition metal catalyst compound. , chiral, capable of producing isotactic or syndiotactic polypropylene; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst, capable of producing atactic polypropylene; and c) recover branched olefin polymer. The composition of claim 7, wherein step a) is conducted by a process wherein said propylene monomers are contacted with said chiral stereo-rigid transition metal catalyst, activated by a co-catalyst of alumoxane or non-coordinating anion precursor. The composition of claim 8, wherein step b) is conducted in a separate reaction by gas phase, slurry or solution polymerization. The composition of claim 7, wherein steps a) and b) are conducted simultaneously. 11. The composition of claim 7, wherein said propylene monomers in step a) are contacted at a temperature of 100 to 110"C. 12. The composition of claim 7, wherein said stereo-transition metal catalyst compound rigid, chiral, is selected from the group consisting of bis-indenyl zirconocenes or hafnocenes bridged with dimethylsilyl 13. The composition of claim 7, wherein said chiral stereo-rigid transition metal catalyst compound is a bis-indenyl zirconocene. bridged with dimethylsilylo 14. The composition of claim 13, wherein said chiral stereo-rigid transition metal catalyst compound further comprises an alumoxane 15. The composition of claim 7, wherein said metal catalyst compound of chiral stereo-rigid transition is dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium dichloride 16. A process for producing a elastomer composition thermoplastic grouper, comprising: a) contacting, in solution, at a temperature of 90 to 120 ° C, propylene monomers with a catalyst composition comprising a chiral stereo-rigid transition metal catalyst compound, capable of of producing isotactic or syndiotactic polypropylene; b) copolyzing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst, capable of producing polypropylene; and c) recovering a branched olefin polymer. The process of claim 16, wherein step a) is conducted by a process in which said propylene monomers are contacted with said chiral stereo-rigid transition metal catalyst, activated by a co-catalyst of alumoxane or non-coordinating anion precursor. 18. The process of claim 17, wherein step b) is conducted in a separate reaction by gas phase, slurry or solution polymerization. The process of claim 16, wherein step a) and step b) are conducted simultaneously in the presence of a mixed catalyst system. The process of claim 16, wherein said propylene monomers in step a) are brought into contact at a temperature of 100 to 110"C. 21. The process of claim 16, wherein said transition metal catalyst compound Stereo-rigid, chiral, is selected from the group consisting of bis-indenyl zirconocenes or hafnocenes bridged with dimethylsilyl 22. The process of claim 16, wherein said chiral stereo-rigid transition metal catalyst compound is a indenyl zirconocene bridged with dimethylsilylo-23. The process of claim 22, wherein said chiral stereo-rigid transition metal catalyst compound further comprises an alumoxane 24. The process of claim 16, wherein said catalyst compound of Stereo-rigid, chiral transition metal is dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium dichloride.