Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-06-18
2003-11-25
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...
C526S152000, C526S153000, C526S160000, C526S170000, C526S340400, C525S333100, C525S333200, C525S371000
Reexamination Certificate
active
06653430
ABSTRACT:
TECHNICAL FIELD
This invention relates to a butadiene polymer having a high cis-bond unit content and a high living chain content, and a process for producing a conjugated diene polymer using a specific metallocene catalyst.
BACKGROUND ART
Metallocene catalsts generally have a high catalytic activity, and therefore, they exhibit a high efficiency for production of polymers and give polymers with well controlled stereoregularity. Further, an attempt of using a metallocene catalyst for the production of rubbers is being made.
Polymerization of butadiene using a cyclopentadienyltitanium trichloride/methylaluminoxane catalyst was proposed in Macromol. Chem. Rapid. Commun., 1990, vol. 11, p519; J. Organomet. Chem., 1993, vol. 451, p67; Macromol. Symp., 1995, vol. 89, p383; and Macromol. Rapid Commun., 1996, vol. 17, p781. This polymerization proceeds with a high activity to give a polymer having a cis-bond unit content of about 80%. However, the polymer is gel-like, and molecular weight, molecular weight distribution, control of a branched structure and living property of the polymer are not described in these references. Further, these references are silent on an introduction of a functional group in activated molecule terminals (hereinafter referred to “terminal modification”), and a reaction of activated molecule terminals with a reactive reagent (hereinafter referred to “coupling-agent”) to give a polymer with a higher molecular weight (hereinafter referred to “coupling”). More specifically polymerization of butadiene using a catalyst prepared by previously contacting cyclopentadienyltitanium trichloride with methylaluminoxane is described in the above cited in Macromol. Chem. Rapid. Commun., 1990, vol. 11, p519, but polymerization conditions and effects thereof are not described.
Japanese Unexamined Patent Publication (hereinafter abbreviated to “JP-A”) No. H8-113610 discloses polymerization of butadiene using a cyclopentadienyltitanium trichloride/methylaluminoxane/triethylaluminum catalyst to give a butadiene polymer having an Mw/Mn of 1.93. However, control of the branched polymer structure, living property of polymerization, and terminal modification and coupling of the polymer are not described.
JP-A H9-77818 discloses a catalyst for polymerization of a conjugated diene, comprising a combination of a transition metal compound, represented by the following formula (1), of group IV of the periodic table with an aluminoxane, which has a high activity and gives a polymer having controlled stereoregularity. It is described in this patent publication that, when butadiene is polymerized with this catalyst, a polymer having a cis-bond unit content of 96% was obtained. However, this patent publication is silent on molecular weight of the polymer, molecular weight distribution thereof, control of the branched polymer structure, living property of polymerization, and terminal modification and coupling of the polymer.
wherein M is a transition metal of group IV of the periodic table, X is hydrogen, a halogen, a C1-12 hydrocarbon group or a C1-12 hydrocarbon-oxy group, Y is a C1-20 hydrocarbon group which may form a ring together with the cyclopentadienyl group, Z is hydrogen or a C1-12 hydrocarbon group, and the pentagon with a circle therein represents a cyclopentadienyl ring structure (which is the same in the formula (3) below).
A metallocene catalyst comprising a transition metal compound of group IV of the periodic table, represented by the following formula (2):
MeO(CO)CH
2
CpTiCl
3
(2)
wherein Me is a methyl group and Cp is a cyclopentadienyl ring structure (which is the same in the following chemical formulae), is described in Macromol. Chem., Macromol. Symp., 1997, vol. 118, p55-60. However, polymerization of a conjugated diene using this metallocene catalyst is not described therein.
Recently, it has been proposed to use the metallocene catalyst comprising the transition metal compound of group IV of the periodic table represented by the formula (2) for polymerization of butadiene in Preprint of the First Symposium on Technology for Novel High-Functional Materials; Industrial Science and Technology Frontier Program, Dec. 10, 1997, p77 (Japan). It is described that this polymerization proceeded with a high activity, and the resulting polybutadiene had a high cis-bond unit content and a molecular weight distribution somewhat narrower than the conventional high-cis butadiene polymers. However, control of the branched polymer structure, living property of polymerization, and terminal modification and coupling of the polymer are not described.
Butadiene polymers having a high molecular weight and at least 90% of a cis-bond unit content, prepared by using a typical coordinate polymerization catalyst containing cobalt, nickel, titanium or neodymium, are known. These butadiene polymers have a broad molecular weight distribution, and a large proportion of branched structures. Even a butadiene polymer having the smallest proportion of branched structure, prepared by using a neodymium-containing coordinate polymerization catalyst, satisfies the relationship between the root-mean-square radius (RMSR, nm) and the absolute molecular weight (MW, g/mol), represented by the following equation:
log(
RMSR
)=0.638×log(
MW
)−2.01
As for the butadiene polymers prepared by using a cobalt, nickel or titanium-containing coordinate catalyst, living property of polymerization, and terminal modification and coupling of the polymers are not known. As for the butadiene polymers prepared by using a neodymium-containing coordinate catalyst, it is known that the polymerization reaction is relatively living, but the content of living chains is not clear. It is presumed from WO 95/04090 that the maximum value of the content of living chains in the polymers with neodymium catalyst is 75%. However, as mentioned above, the polymers have a large proportion of branched structures and a broad molecular weight distribution, i.e., Mw/Mn of 3.1 or larger.
A process for producing a conjugated diene polymer by polymerization using a neodymium-containing coordinate catalyst followed by coupling is known (for example, JP-A S63-178102, JP-A S63-297403, JP-A S63-305101). However, the polymer before the coupling is presumed as having a broad molecular weight distribution, namely, Mw/Mn of at least about 3, from the GPC eluation curve. This polymer has a large proportion of branched structures and the degree of coupling is not clear.
With an organolithium catalyst, living polymerization of butadiene proceeds, and results in a terminal-modified polymer or a coupled polymer, which have a high molecular weight and a narrow molecular weight distribution, and are substantially free from a branched structure. But, the cis-bond unit content of the polymer is not more than 40%.
To sum up, according to the conventional techniques, it was impossible to produce a conjugated diene polymer by a stereospecifically highly active living polymerization procedure, and also to obtain a conjugated diene polymer having a high molecular weight and a narrow molecular weight distribution, and substantially not having a branched structure, and having a high cis-bond unit content. It was also impossible to produce a butadiene polymer by a stereospecifically (i.e., in a manner by which a polymer with a high cis-bond unit content is obtained) highly active living polymerization procedure and to introduce a functional group to a molecule chain terminal or effect coupling.
DISCLOSURE OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a butadiene polymer having a high living chain content and a high 1,4-cis-bond unit content, and substantially not having a branched structure.
Another object of the present invention is to provide a process for producing a conjugated diene polymer wherein a high living property of polymerization is attainable by controlling a polymerization temperature.
Still other objects of the present invention are to provide a butadiene polymer having a high cis-b
Asai Michihiko
Fukui Yoshifumi
Hagihara Hideaki
Jin Jizhy
Kase Toshio
Armstrong Westerman & Hattori, LLP
Japan as Represented by Director General of the Agency of Indust
Soga Yoshiya
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