Process for copolymerizing conjugated dienes with monovinyl aromatic monomers

Abstract

Abstract A DIENE OF 4 TO 6 CARBON ATOMS AND STYRENE OR OTHER VINYL AROMATIC MONOMER, INCLUDING AKYLATED VINYL AROMATIC MONOMERS, ARE COPOLYMERIZED IN A HYDROCARBON SOLVENT USING A SUBSTANTIAL AMOUNT OF EACH MONOMER AND UTILIZING AS THE INITIATOR, AN ALKALI METAL HYDROCARBON (PREFERABLY N-BUTYLLITHIUM) COMPLEXED WITH ANOTHER ALKALI METAL. THE COMPLEX MAY BE FORMED BY COMPLEXING HYDROCARBON LITHIUM WITH A DIFFERENT ALKALI METAL. THE COMPLEXING METAL IS USED IN AN AMOUNT NO MORE THAN THE AMOUNT OF ALKALI METAL INITIALLY PRESENT IN THE INITIATOR. THUS, IF THE INITIATOR BE PREPARED FROM HYDROCARBON LITHIUM, THE RATIO OF (A) THE AMOUNT OF ALKALI METAL OTHER THAN LITHIUM IN THE COMPLEXED INTIATOR TO (B) THE AMOUNT OF LITHIUM IN THE COMPLEXED INITIATOR, MAY BE ONE PART OF THE OTHER ALKALI METAL TO 50 PARTS OFLITHIUM, AND PREFERABLY 5 TO 20 PARTS OF LITHIUM. THE RESULTING COPOLYMER IS A COPOLYMER OF SUBSTANTIALLY CONSTANT COMPOSITION (I.E. A COPOLYMER CONTAINING NO SUBSTANTIAL BLOCK OF VINYL MONOMER), AND IT HAS A LOW VINYL CONTENT. THE DIENE MAY BE BUTADIENE, ISOPRENE, PIPERYLENE OR 2,3-DIMETHYLBUTADIENE OR A MIXTURE THEREOF. THE VINYL AROMATIC MONOMER MAY BE STYRENE OR AN ALKYLATED STYRENE OR VINYL NAPHTHYLENE OR ALKYLATED VINYL NAPHTHYLENE OR A MIXTURE THEREOF.

Inventors

• 👤 A Halasa

Bibliographic Details