Chemistry of hydrocarbon compounds – Product blend – e.g. – composition – etc. – or blending process... – Component of indefinite molecular weight greater than 150
Reexamination Certificate
2000-04-07
2002-10-01
Howard, Jacqueline V. (Department: 1764)
Chemistry of hydrocarbon compounds
Product blend, e.g., composition, etc., or blending process...
Component of indefinite molecular weight greater than 150
C585S512000, C585S523000, C585S525000, C585S526000, C585S527000, C525S246000, C525S249000
Reexamination Certificate
active
06459005
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel ethylene/&agr;-olefin copolymer, method for producing the same, and its use.
More particularly, the present invention relates to an ethylene/&agr;-olefin copolymer having an unsaturated bond, such as vinyl or vinylidene type, at the molecular terminal at a ratio of 95% or more, specific molecular weight and composition, and method for producing the same and its use.
PRIOR ART
Lubricant oils, such as gear and engine oils, are known to comprise a mineral oil or synthetic oil, such as poly-&agr;-olefin and low-molecular-weight ethylene/&agr;-olefin copolymer. It is also known that these lubricant oils are incorporated with a viscosity index improver, such as ethylene/&agr;-olefin copolymer and polymethacrylate, to improve their viscosity/temperature characteristics. These lubricant oil compositions are required to exhibit good viscosity characteristics (in particular, low-temperature fluidity), and shear, heat and oxidation stability.
Lubricant oils, such as engine oil, gear oil, grease and metal machining oil, are also incorporated with a variety of other additives, to improve their functions. Many of these additives are polar compounds, which have low affinity for non-polar base oils. Therefore, they are frequently sparingly soluble in base oils, which tends to cause problems, such as limitations on their dose rates or decreased effects. Recently, these problems have been more noted, since mineral oils as the base oils are replaced by synthetic oil of lower polarity to satisfy the severer requirements of lubricant oils. As a result, a solubilizing agent has been in demand to increase solubility of these polar additives in non-polar base oils.
In the plastic industry, it is a common practice to incorporate a synthetic lubricant oil (e.g., ethylene/&agr;-olefin copolymer or &agr;-olefin oligomer) in resins, in order to improve their friction/&agr;abrasion characteristics (sliding characteristics). These resins used in this case, however, are normally polar ones, such as polyacetal, polyamide and polyester. Therefore, the above-mentioned non-polar synthetic lubricants are not well compatible with these resins, possibly causing problems, e.g., deteriorated strength and surface exfoliation, when they are used. A solubilizing agent, therefore, has been strongly demanded to improve dispersibility of a non-polar lubricant oil in a polar resin.
An ethylene/&agr;-olefin copolymer for the above lubricant oil or additive has been produced in the presence of a vanadium-based catalyst composed of a vanadium compound and organoaluminum compound, as disclosed by Japanese Patent Publication Nos. 1163/1990 and 7998/1990. However, the vanadium-based catalyst is insufficient in polymerization activity.
It is known that the copolymer can be produced in the presence of a catalyst of high polymerization activity, which is composed of a metallocene compound (e.g., zirconocene) and organoaluminumoxy compound (aluminoxane), as disclosed by Japanese Patent Laid-Open No. 221207/1986 and Japanese Patent Publication No. 121969/1995. The ethylene/&agr;-olefin copolymer produced by the methods of prior literature is characterized by having an unsaturated bond at the molecular terminal and easily modified to introduce a functional group. However, production of such a copolymer sufficiently low in molecular weight to be liquid needs a large quantity of hydrogen as the molecular weight modifier, which causes various problems, e.g., decreased polymerization yield and massive disappearance of the unsaturated bonds at the molecular terminals by hydrogenation, which serve as the active sites for the modification reactions.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide an ethylene/&agr;-olefin copolymer of specific structure, exhibiting excellent performance as a lubricant oil additive, capable of having various functional groups in high yield, and applicable as raw material for various solubilizing agents. It is another object of the present invention to provide a method for producing the above copolymer. It is still another object of the present invention to provide use of the above copolymer.
SUMMARY OF THE INVENTION
The present invention provides a novel ethylene/&agr;-olefin copolymer effectively solving the above problems, a method of producing the same, and use of the same.
That is, the present invention provides a novel ethylene/&agr;-olefin copolymer characterized by:
(1) comprising ethylene unit of 30 to 80% by mol and &agr;-olefin having 3 to 10 carbon atoms of 20 to 70% by mol;
(2) having a number-average molecular weight (Mn) of 500 to 12,000, determined by gel permeation chromatography (GPC) and molecular weight distribution (Mw/Mn) of 3 or less;
(3) having a kinetic viscosity at 100° C. of 10 to 5,000 mm
2
/s;
(4) that at least 95% of whole polymer chains have at least one unsaturated bond at molecular terminal thereof; and
(5) having a B value, given by the following formula (I), of 1.0 to 2.0:
B=P
OE
/(2
P·P
E
) (I)
wherein, P
E
is molar fraction of the ethylene unit in the copolymer, P
O
is molar fraction of the &agr;-olefin unit in the copolymer, and P
OE
is proportion of number of &agr;-olefin/ethylene sequences to number of all the dyad sequences.
The ethylene/&agr;-olefin according to the present invention can be obtained by copolymerizing ethylene and &agr;-olefin of 3-10 carbon atoms using an olefin polymerization catalyst comprising:
(A) a transition metal compound represented the following formula (II) and
(B) at least one compound selected from the group consisting of:
(B-1) an organometallic compound,
(B-2) an organoaluminum oxy-compound, and
(B-3) a compound reacting with the transition metal compound (A) to form an ion pair
wherein M is a transition metal atom selected from Group 3 to 11 of the periodic table;
m is an integer of 1-6;
R
1
to R
6
may be the same as or different from each other, and is a hydrogen atom, a halogen atom, a hydrocarbon group, a heterocyclic compound residual group, an oxygen-containing group, a nitrogen-containing group, a boron-containing group, a sulfur-containing group, a phosphorus-containing group, a silicon-containing group, a germanium-containing group or a tin-containing group, with the proviso that two or more of these may be bonded to each other to form a ring, and when m is 2 or more, any two of groups represented by R
1
to R
6
may be bonded;
n is a number satisfying a valence of M;
X is a hydrogen atom, a halogen atom, a hydrocarbon group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a boron-containing group, an aluminum-containing group, a phosphorus-containing group, a halogen-containing group, a heterocyclic compound residual group, a silicon-containing group, a germanium-containing group or a tin-containing group, with the proviso that when n is 2 or more, plural groups represented by X may be the same as or different from each other, and plural groups represented by X may be bonded to each other to form a ring.
The ethylene/&agr;-olefin copolymer according to the invention can be used as lubricant base oil excellent in temperature/viscosity property, shear stability, heat-resistance/oxidative stability. Further, the ethylene/&agr;-olefin copolymer can be used as a viscosity index improver excellent in temperature/viscosity property and shear stability by adding to other base oil, such as a mineral oil or an &agr;-olefin oligomer.
The ethylene/&agr;-olefin copolymer has features in that 95% or more of whole polymer chain has at least one unsaturated bond at a molecular terminal having a reactivity, so that various kinds of functional groups can be easily introduced, and, hence, it is easy to modify to a functional ethylene/&agr;-olefin copolymer such as a polar additive or a solubilizing agent with a polar resin.
In order to obtain the modified ethylene/&agr;-olefin copolymer of the present invention, the above mentioned unsaturated bond at a molecular terminal in the ethylene/
Fujita Terunori
Hirano Hideki
Mitani Makoto
Saito Junji
Howard Jacqueline V.
Mutsui Chemicals, Inc.
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