US 5,688,735 A · Method for controlling the melting points and molecular weights of syndiotactic polyolefins using metallocene catalyst systems

Abstract

This invention is for a method for varying the melting points and molecular weights of syndiotactic polyolefins by using metallocene catalysts with substituents on the aryl rings of a fluorene ligand in certain positions. Electron donating substituents, for example, dialkylamino, halogen, and alkoxy groups, when present on fluorene at C1, C2, C3 or C2 and C7 render the catalyst less active and decrease the polymer molecular weight. Electron donating substituents, such as alkyl, dialkylamino, halogen or alkoxy, at C4 not only increased the catalyst efficiency but also dramatically increased the polymer molecular weight. Bulky hydrocarbyl substituents, such as alkyl, cycloalkyl and aryl groups, at C2 and C7 increase the melting point. Bulky substituents such as hydrocarbyl groups like alkyl, cycloalkyl, aryl, alkoxy and dialkylamino groups etc., at C4/C5 decrease the melting point. When multiple substituents are present on fluorene, their effects are additive.

Claims45

Dependent claims

A catalyst system for polymerizing propylene to produce a syndiotactic polypropylene comprising:

a) a metallocene of the general formula:
R"(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n)MeQ.sub.p
wherein (C.sub.5 H.sub.4) is a cyclopentadienyl ring and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) is a fluorenyl radical;
R' is a hydrocarbyl radical, halogen, an alkoxy, an alkoxy alkyl or an alkylamino radical having from 1-20 carbon atoms, each R' may be the same or different;
R" is a structural bridge between the (C.sub.5 H.sub.4) and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) rings to impart stereorigidity;
Q is a hydrocarbon radical or a halogen;
Me is a Group IVB metal;
1.ltoreq.m.ltoreq.4;
0.ltoreq.n.ltoreq.4;
and p is the valence of Me minus 2;
wherein R' is an electron donating substituent on the fluorene ligand at C1, C2, or C3 and has the ability to donate electrons equal to or greater than that for methoxy;
b) a co-catalyst selected from the group consisting of an organoaluminum compound of the general formula (R-A1-O) in the cyclic form or R(R-Al-O).sub.n AlR.sub.2 in the linear form wherein R is an alkyl group with 1-5 carbons and n is an integer from about 1 to about 20, a neutral Lewis acid and an ionic ionizing agent.

9 more elements

A catalyst system for polymerizing propylene to produce a syndiotactic polypropylene comprising:

a) a metallocene of the general formula:
R"(C.sub.5 H.sub.4) (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) MeQ.sub.p
wherein (C.sub.5 H.sub.4) is a cyclopentadienyl ring and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) is a fluorenyl radical;
R' is a hydrocarbyl radical, halogen, an alkoxy, an alkoxy alkyl or an alkylamino radical having from 1-20 carbon atoms, each R' may be the same or different;
R" is a structural bridge between the (C.sub.5 H.sub.4) and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) rings to impart stereorigidity;
Q is a hydrocarbon radical or a halogen;
Me is a Group IVB metal;
1.ltoreq.m.ltoreq.4;
0.ltoreq.n.ltoreq.4;
and p is the valence of Me minus 2;
wherein R' is an electron donating substituent on the fluorene ligand at both C2 and C7 and has the ability to donate electrons equal to or greater than that for a dialkylamino or halogen;
b) a co-catalyst selected from the group consisting of an organoaluminum compound of the general formula (R-Al-O) in the cyclic form and R(R-Al-O).sub.n AlR.sub.2 in the linear form wherein R is an alkyl group with 1-5 carbons and n is an integer from about 1 to about 20, a Lewis acid and an ionic ionizing agent.

9 more elements

Dependencies are inferred from the claim text.

Method for controlling the melting points and molecular weights of syndiotactic polyolefins using metallocene catalyst systems

Life of this patent

Method for controlling the melting points and molecular weights of syndiotactic polyolefins using metallocene catalyst systems

Life of this patent

Abstract

Claims45