Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-08-15
2002-10-22
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S124600, C526S124200, C526S158000, C526S348000, C502S103000, C502S104000, C502S116000, C502S158000
Reexamination Certificate
active
06469112
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to olefin polymerization catalyst systems. In particular, the present invention relates to catalyst systems for making olefin polymers and copolymers and methods of making the catalyst systems and alpha-olefin polymers and copolymers.
BACKGROUND OF THE INVENTION
Polyolefins are a class of polymers derived from simple olefins and include polypropylene and polybutene. Known methods of making polyolefins involve the use of Ziegler-Natta polymerization catalysts. These catalysts polymerize vinyl monomers using a transition metal halide to provide a stereoregulated polymer.
Numerous Ziegler-Natta polymerization catalysts exist. The catalysts have different characteristics and/or lead to the production of polyolefins having diverse properties. For example, certain catalysts have high activity while other catalysts have low activity, and similarly certain catalysts have a long life while other catalysts have a short life. Moreover, polyolefins made with the use of Ziegler-Natta polymerization catalysts vary in stereoregularity, molecular weight distribution, impact strength, melt-flowability, rigidity, heat sealability, isotacticity, and the like.
In the polymerization of alpha-olefins having 3 or more carbon atoms in particular, an electron donor is incorporated into the Ziegler-Natta polymerization catalyst to promote increased stereospecificity. However, using an electron donor to promote increased stereospecificity of poly-alpha-olefins in a Ziegler-Natta polymerization scheme tends to cause large losses in catalyst activity. While lower levels of many characteristics associated with Ziegler-Natta polymerization catalysts can be tolerated, it is difficult to accommodate compromises in catalyst activity. As a result, there is an unmet need for Ziegler-Natta polymerization catalysts (and methods associated therewith) that possess high catalyst activity in addition to other desirable features.
U.S. Pat. Nos. 4,784,983 and 4,861,847 relate to a catalyst system for use in olefinic polymerization and copolymerization is comprised of the following components: (A) a solid product consisting essentially of titanium, magnesium, halogen, polycarboxylic acid esters and organic phosphorus compounds, (B) an organic aluminum compound, and (C) an organic silicon compound.
U.S. Pat. No. 4,829,038 relates to an olefin polymerization catalyst system comprising a solid, hydrocarbon-insoluble, magnesium-containing, titanium-containing, electron donor-containing component; an alkyl aluminum compound; and organosilane compound selected from the group consisting of diisobutyidimethoxysilane, diisopropyidimethoxysilane, t-butyltrimethoxysilane and di-t-butyidimethoxysilane, and mixtures thereof.
U.S. Pat. Nos. 4,990,479 and 5,438,110 relate to an olefin polymerization catalyst formed from (A) a solid titanium catalyst component containing magnesium, titanium and halogen as essential ingredients, (B) an organoaluminum compound, and (C) an organosilicon compound containing a cyclopentyl group, a cyclopentenyl group, a cyclopentadienyl group or a derivative derived from any of these groups.
U.S. Pat. No. 5,244,989 relates to a method for producing a stereospecific polyolefin in the presence of a catalyst comprising a transition metal compound and an organometallic compound, wherein a catalyst system is used which comprises: (A) a solid catalyst component prepared by reacting (i) a homogeneous solution prepared by reacting (i-1) magnesium and a hydroxylated organic compound, (i-2) an oxygen-containing organic compound of titanium and/or (i-3) an oxygen-containing organic compound of silicon, with an oxygen-containing organic compound of aluminum and/or a boron compound, with (ii) at least one aluminum halide compound to obtain a solid product, reacting to this solid product (iii) an electron-donative compound and (iv) a titanium halide compound to obtain a solid component, and further reacting to this solid component (v) silicon tetrachloride and/or an alkyl-substituted product of silicon tetrachloride, (B) at least one member selected from the group consisting of organometallic compounds of Groups IA, IIA, IIB, IIIB and IVB of the Periodic Table, and (C) an electron-donative compound.
U.S. Pat. No. 5,773,537 relates to catalyst systems of the Ziegler-Nafta type containing, as active components a) a titanium-containing solid component in whose preparation a titanium compound, a compound of magnesium, a halogenating agent and an electron donor component are used, b) an aluminum compound and c) as a further electron donor component, an organosilicon compound of the formula R
1
R
2
Si(OR
3
)
2
where R
1
is C
1
-C
10
-alkyl or C
3
-C
8
-cycloalkyl, excluding sec-butyl, R
2
is sec-butyl and R
3
is C
1
-C
8
-alkyl.
SUMMARY OF THE INVENTION
The present invention provides alpha-olefin polymerization catalyst systems, methods of making the alpha-olefin polymerization catalyst systems, and methods of polymerizing (and copolymerizing) alpha-olefins involving the use of (cycloalkyl)methyl moiety containing external electron donors. The (cycloalkyl)methyl moiety containing external electron donors of the alpha-olefin polymerization catalyst systems contribute to the production of high xylene soluble poly-alpha-olefins while simultaneously maintaining high catalytic efficiency of the catalysts. The use of (cycloalkyl)methyl moiety containing external electron donors permits the tolerance of a large margin of error in the amount of external electron donor employed without effecting the properties of the catalyst system or resulting polymer.
One aspect of the invention relates to a catalyst system for use in olefinic polymerization, containing a solid titanium catalyst component; an organoaluminum compound having at least one aluminum-carbon bond; and an organosilicon compound comprising a (cycloalkyl)methyl group.
Another aspect of the invention relates to a catalyst system for use in olefinic polymerization, containing a solid titanium catalyst component prepared by contacting a titanium compound and a magnesium compound, the solid titanium catalyst component comprising from about 0.01 to about 500 moles of the titanium compound per mole of the magnesium compound; an organoaluminum compound having at least one aluminum-carbon bond, wherein the catalyst system has a mole ratio of aluminum to titanium from about 5 to about 1,000; and an organosilicon compound comprising a (cycloalkyl)methyl group, wherein the catalyst system has a mole ratio of the organoaluminum compound to the organosilicon compound from about 2 to about 90.
Yet another aspect of the invention relates to a method of making a catalyst for use in olefinic polymerization, involving the steps of reacting a Grignard reagent having a (cycloalkyl)methyl group with an orthosilicate to provide an organosilicon compound having a (cycloalkyl)methyl moiety; and combining the organosilicon compound with an organoaluminum compound having at least one aluminum-carbon bond and a solid titanium catalyst component to form the catalyst.
Still yet another aspect of the invention relates to a polymerization process, involving polymerizing or copolymerizing an alpha-olefin in the presence of a catalyst system containing a solid titanium catalyst component; an organoaluminum compound having at least one aluminum-carbon bond; and an organosilicon compound comprising a (cycloalkyl)methyl group.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to catalyst systems and methods of making poly-alpha-olefins, such as polypropylene, using catalyst systems containing an organosilicon compound containing a (cycloalkyl)methyl group, and in particular, an organosilicon compound containing a (cycloheptyl)methyl group, a (cyclohexyl)methyl group, a (cyclopentyl)methyl group(cyclobutyl)methyl group and/or a (cyclopropyl)methyl group. The cycloalkyl groups may be substituted (such as lower alkyl substituted (cycloalkyl)methyl) or unsubstituted. Lower alkyl groups have about 4 carbons or less. Poly-alpha-olefi
Cheng Chung-Ping
Spencer Michael D.
Choi Ling-Siu
Engelhard Corporation
Keller Raymond F.
Wu David W.
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