Abstract This invention relates to the preparation of solution polymers and rubbers from vinyl monomers using a new catalyst complex of a barium di-tert-alkoxide-hydroxide salt and an organic lithium compound. In particular, homopolymers and copolymers of butadiene with styrene and/or isoprene, prepared with this catalyst, are uniquely characterized by the butadiene units having a low vinyl content (not over about 12%) and a trans-1,4 structure of from about 70 to 81%. Also, the copolymer has a random comonomer sequence distribution. This molecular structure permits elastomers containing little or no styrene to have sufficient stereoregularity to crystallize. Furthermore, the butadiene homopolymer and copolymer with styrene and/or isoprene exhibit a broad molecular weight distribution as well as tack and green-strength which are valuable properties for a rubber to possess when building tires.
A rubbery polymer selected from the group consisting of homopolybutadiene-1,3 and a random copolymer of butadiene-1,3 and up to about 15% by weight total of said copolymer of copolymerized styrene and/or isoprene, said polymer exhibiting: a. a glass transition temperature of from about -80° to -100° C. as determined by differential thermal analysis, b. a crystalline melting point (peak values) in the unstretched state from about -10° to +43° C. as determined by differential thermal analysis, c. a trans-1,4 content of from about 70 to 81% and a vinyl content of up to about 12% for the butadiene units, d. a heterogeneity index of from about 4 to 40, e. a number average molecular weight of from about 20,000 to 300,000, f. crystallinity when stretched in the uncompounded and uncured state as shown by x-ray diffraction data, g. green strength and building tack, and h. a broad molecular weight distribution as determined by gel permeation chromotography.
Claim 2
Dependent Claim
156 words
A rubbery polymer selected from the group consisting of homopolybutadiene-1,3 and a random copolymer of butadiene-1,3 and up to about 15% by weight total of said copolymer of copolymerized styrene and/or isoprene, said polymer exhibiting: a. a glass transition temperature of from about -80° to -100° C. as determined by differential thermal analysis, b. a crystalline melting point (peak values) in the unstretched state from about -10° to +43° C. as determined by differential thermal analysis, c. a trans-1,4 content of from about 70 to 81% and a vinyl content of up to about 12% for the butadiene units, d. a heterogeneity index of from about 4 to 40, e. a number average molecular weight of from about 20,000 to 300,000, f. crystallinity when stretched in the uncompounded and uncured state as shown by x-ray diffraction data, g. green strength and building tack, and h. a broad molecular weight distribution as determined by gel permeation chromotography.
Claim 3
Dependent Claim
15 words
A rubbery copolymer according to claim 1 where the second named copolymerized monomer is styrene.
Claim 4
Dependent Claim
15 words
A rubbery copolymer according to claim 1 where the second named copolymerized monomer is isoprene.
Claim 5
Dependent Claim
20 words
A rubbery copolymer according to claim 1 where the second named copolymerized monomer is a mixture of isoprene and styrene.