Oligomeric oxolanyl alkanes as modifiers for polymerization of dienes using lithium-based initiators
AssigneeThe Firestone Tire & Rubber Company
InventorJames E. Hall
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Abstract
A process and catalyst system is disclosed herein for the preparation of (co)polymers having a 1,2-microstructure of between 20 and 95 percent. These (co)polymers are prepared in a hydrocarbon or other non-polar solvent from a monomer system which contains at least one 1,3-diene monomer. The catalyst system which is employed in the production of the (co)polymers of the present invention is a combination of (1) an anionic initiator based on lithium, and (2) a modifier compound selected from the group consisting of linear and cyclic oligomeric oxolanyl alkanes.
Claims10
A catalyst system comprising:
- (a) at least one anionic initiator based on lithium, and
- (b) at least one oxolanyl compound selected from the group consisting of:
- ##STR2## wherein R.sub.1 and R.sub.2 independently are hydrogen or an alkyl group and the total number of carbon atoms in --CR.sub.1 R.sub.2 -- ranges between one and nine inclusive;
- y is an integer of 1 to 5 inclusive, y' is an integer of 3 to 5 inclusive, R.sub.3 ', R.sub.3, R.sub.4 and R.sub.5 independently are --H or --C.sub.n H.sub.2n+1 wherein n=1 to 6.
A process for the preparation of a polymer by polymerizing:
- (A) 15 to 100 percent of at least one 1,3-diene monomer, and
- (B) 0 to 85 percent of one or more reactive monomers which are copolymerizable with said 1,3-diene monomers,
- in an inert non-polar solvent in the presence of a catalytically effective amount of a catalyst system comprising:
- (a) at least one anionic initiator based on lithium, and
- (b) at least one oxolanyl modifier compound selected from the group consisting of:
- ##STR3## wherein R.sub.1 and R.sub.2 independently are hydrogen or an alkyl group and the total number of carbon atoms in --CR.sub.1 R.sub.2 -- ranges between one and nine inclusive;
- y is an integer of 1 to 5 inclusive, y' is an integer of 3 to 5 inclusive, R.sub.3 ', R.sub.3, R.sub.4 and R.sub.5 independently are --H or --C.sub.n H.sub.2n+1 wherein n=1 to 6;
- in which the molar ratio of the anionic initiator (a) to the oxolanyl modifier (b) ranges between about 20.0/1.0 to about 1.0/20.0, the millimoles of the anionic initiator per 100 grams of the (A+B) monomers ranges between about 0.2 and about 100, the polymerization temperature is maintained between about 0.degree. C. and 160.degree. C., wherein said polymer contains a 1,2-microstructure in the 1,3-diene monomer contributed units ranging between 20 and 95 percent.
Dependencies are inferred from the claim text.