Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-09-07
2001-12-11
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S126000, C526S127000, C526S131000, C526S132000, C526S134000, C526S160000, C526S346000, C526S347000, C526S348000, C526S943000
Reexamination Certificate
active
06329479
ABSTRACT:
The present invention relates to a transition metal compound as catalyst component for polymerization, a method for producing an aromatic vinyl compound type polymer employing it, a method for producing an aromatic vinyl compound polymer and an aromatic vinyl compound-olefin copolymer, having an isotactic stereoregularity, and a novel aromatic vinyl compound-olefin copolymer.
Also, the present invention provides a non-crystalline aromatic vinyl compound-ethylene random copolymer having a high random property (low alternating property) of novel structure, having an isotactic stereoregularity and having a feature that even after sufficiently subjecting to crystallization, a crystallinity derived from an aromatic vinyl compound-ethylene alternating structure is not observed. Further, the present invention provides a novel transition metal compound for as catalyst component for polymerization.
For the production of a copolymer of an olefin with an aromatic vinyl compound, such as ethylene with styrene, studies have been conducted primarily by using so-called heterogeneous Ziegler-Natta catalysts (e.g. Polymer Bulletin, 20, 237-241 (1988), Macromolecules, 24, 5476 (1991)). However, conventional heterogeneous Ziegler-Natta catalyst systems are not so practical, since the catalytic activities are low, the styrene content in the product is very low at a level of a 1 mol %, or the product does not have a uniform regular copolymer structure or contains a substantial amount of homopolymers such as polyethylene and isotactic or atactic polystyrene.
Further, the stereoregularity of the obtained polystyrene is isotactic, but in the copolymerization, no stereoregularity of an alternating structure of styrene and an olefin is observed, or an alternating structure itself is not substantially contained.
Further, some styrene-ethylene copolymers obtainable by using so-called single-site catalyst systems comprising a transition metal compound and an organoaluminum compound, and methods for their production, have been known.
JP-A-3-163088 and JP-A-7-53618 disclose styrene-ethylene copolymers where no normal styrene chain is present i.e. so-called pseudo random copolymers, obtained by using a complex having a so-called constrained geometrical structure. Here, a normal styrene chain is meant for a head-to-tail bond chain. Further, hereinafter styrene may sometimes be represented by St.
However, phenyl groups in the alternating structure of styrene-ethylene present in such pseudo random copolymers, have no stereoregularity. Further, no normal styrene chain is present, whereby the content of styrene can not exceed 50 mol %. Further, the catalytic activities are practically inadequate.
JP-A-6-49132 and Polymer Preprints, Japan, 42, 2292 (1993) disclose methods for producing similar styrene-ethylene copolymers wherein no normal St chain is present, i.e. so-called pseudo random copolymers, by using a catalyst comprising a bridged metallocene type Zr complex and a cocatalyst.
However, according to Polymer Preprints, Japan, 42, 2292 (1993), phenyl groups in the alternating structure of styrene-ethylene present in such pseudo random copolymers, have no substantial stereoregularity. Further, like in the case of a complex having a constrained geometrical structure, no normal styrene chain is present, and the styrene content can not exceed 50 mol %. The catalytic activities are also practically inadequate.
Further, it has recently been reported to produce a styrene-ethylene copolymer close to an alternating copolymer having a stereoregularity under a condition of an extremely low temperature (−25° C.) by using 1,2-ethylene(—CH
2
—CH
2
—) bridged bisindenyl type Zr complex; rac[ethylenebis(indenyl)zirconium dichloride] (Macromol. Chem., Rapid Commun., 17, 745 (1996)).
However, from the 13C-NMR spectrum disclosed, it is evident that this copolymer has no normal styrene chain. Further, if copolymerization is carried out at a polymerization temperature of at least room temperature by using this complex, only a copolymer having a low styrene content and a low molecular weight is obtainable.
On the other hand, a styrene-ethylene alternating copolymer obtainable by using a Ti complex having a substituted phenol type ligand, is known (JP-A-3-250007 and Stud. Surf. Sci. Catal., 517 (1990)). This copolymer has a feature that it consists essentially of an alternating structure of ethylene and styrene and contains substantially no other structure such as an ethylene chain, a structure comprising an ethylene chain and styrene or a structure of e.g. a head-to-head or tail-to-tail bond (hereinafter referred to as a heterogeneous bond) of styrene. The alternating index (value &lgr; in the present specification) of the copolymer is at least 70, substantially at least 90.
Namely, the resulting copolymer is a copolymer having a very high degree of alteration and consisting substantially solely of the alternating structure, whereby it is substantially difficult to change the compositional ratio of the copolymer consisting of 50 mol % of ethylene and 50 mol % of styrene. Further, the stereoregularity of phenyl groups is isotactic, but the isotactic diad index m is about 0.92, whereby the melting point is low at a level of from 110 to 120° C.
Further, the weight average molecular weight is low at a level of 20,000, which is inadequate to provide practically useful physical properties as a crystalline polymer. It should also be added that the catalytic activities are very low, and the copolymer can hardly be regarded as practically useful, since it is obtained as a mixture with e.g. syndiotactic polystyrene.
It has been attempted to produce a copolymer of a propylene with styrene by means of a Solvay type Ziegler-Natta catalyst (Macromolecules, 22, 2875 (1989)). However, the catalytic activities are low, and the styrene content is at a level of 4.4 mol % at best. With respect to a single-site catalyst system comprising a transition metal compound and an organoaluminum compound, a case wherein a Ewen-type zirconium complex which is a so-called metallocene catalyst, is employed for copolymerization of propylene with styrene, is known (JP-A-8-269134). However, the styrene content of the copolymer thereby obtainable is as low as a few %, and the stereoregularity is syndiotactic.
The production of an isotactic aromatic vinyl compound polymer such as an isotactic polystyrene, has been studied by means of a so-called heterogeneous Ziegler-Natta catalyst.
For example, such a catalyst is disclosed in Macromolecules, 24, 5476 (1991), but the catalytic activities are low, and as a fate of a heterogeneous Ziegler-Natta catalyst, due to non-uniform active sites, the molecular weight distribution (Mw/Mn) tends to be as broad as at least 3, and cation polymerization and other polymerizations tend to simultaneously proceed, and a substantially a large amount of atactic polystyrene is usually produced as a by-product.
On the other hand, in the polymerization of styrene using a single-site catalyst, syndiotactic polystyrene is usually obtained. Only when a nickel-type non-metallocene complex is used, formation of isotactic polystyrene has been reported, for example, in Macromolecules, 29, 4172 (1996). However, the molecular weight, the catalytic activities and the stereoregularities are all inadequate.
In any case, no isotactic polystyrene has been obtained with a system using a metallocene complex as a catalyst component.
It is an object of the present invention to provide a metal compound for polymerization, a method for producing an aromatic vinyl compound type stereoregular polymer by using it, a method for producing an aromatic vinyl compound polymer and an aromatic vinyl compound-olefin copolymer, having isotactic stereoregularity, and a novel aromatic vinyl compound-olefin copolymer.
It is another object of the present invention to provide an aromatic vinyl compound-ethylene random copolymer having a high random property (low alternating property) and having substantially no crystallinity derived from alternating structure.
Fi
Arai Toru
Nakajima Masataka
Otsu Toshiaki
Suzuki Shigeru
Denki Kagaku Kogyo Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Teskin Fred
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