Abstract: A counter tapered diblock copolymer composition comprises a monovinyl aromatic monomer A polymerized with a conjugated diene monomer B to form the structure A-[A/B], where the [A/B] block is a copolymer of the A and B monomers that is counter tapered, which means the ratio of B to A is lower proximal to the A block relative to the ratio of B to A distal to the A block. The [A/B] block preferably has a vinyl content that is higher proximal to the A block relative to the vinyl content distal to the A block. The diblock copolymer is preferably partially coupled or formed with a multifunctional initiator to provide a mixture of the diblock copolymer composition and a linear (A-[A/B])-X-([B/A]-A) structure and/or a coupled radial and/or multiarm structure (A-[A/B])n-X, where X is the residue of a coupling agent or an initiator. Asphalt and adhesive compositions are made with the diblock copolymer composition and with the mixture.

Abstract: The present invention provides a modified diene copolymer composition having a modified A-B-C or C-B-A copolymer comprising at least one conjugated diene monomer and at least one unsubstituted vinyl aromatic monomer and at least one substituted vinyl aromatic monomer, wherein each block or segment in the modified A-B-C or C-B-A copolymer is either a homopolymer or a copolymer comprising at least one conjugated diene monomer and/or at least one unsubstituted vinyl aromatic monomer and/or at least one substituted vinyl aromatic monomer, wherein any of the copolymers have a distribution configuration that is tapered, counter tapered, random or controlled, and wherein any of the homopolymers or the copolymers comprising at least one conjugated diene monomer and/or at least one unsubstituted vinyl aromatic monomer may be in-chain and/or chain-end modified with at least one unit of at least one substituted vinyl aromatic monomer; optionally having a block copolymer made from the modified A-B-C or C-B-A copolymer, w

Abstract: Dual composition block copolymers made from conjugated diene and monovinyl aromatic monomers in batch organolithium initiated polymerization show advantageous performance in the production of crosslinked microcellular rubber compounds and pressure sensitive hot melt adhesives. The dual composition block copolymers are partially coupled with a coupling agent linking inner monovinyl aromatic blocks. Their un-coupled low molecular weight fraction has greater monovinyl aromatic repeating unit content than their coupled high molecular weight fraction. Crosslinked microcellular rubber articles made from the dual composition block copolymers exhibit lower density, smaller and more homogeneous cell size, higher softness and higher resiliency than prior art block copolymers. Rubber compounding of formulations comprising the dual composition block copolymers proceed at slightly lower torque and slightly lower temperature than with prior art block copolymers.

Abstract: Dual composition block copolymers made from conjugated diene and monovinyl aromatic monomers in batch organolithium initiated polymerization show advantageous performance in the production of crosslinked microcellular rubber compounds and pressure sensitive hot melt adhesives. The block copolymers are partially coupled molecules with a coupling agent linking inner monovinyl aromatic blocks. An un-coupled low molecular weight fraction has greater monovinyl aromatic repeat unit content than a coupled high molecular weight fraction. Crosslinked microcellular rubber articles made from the block copolymers exhibit lower density, smaller and more homogeneous cell size, higher softness and higher resiliency than prior art block copolymers. Rubber compounding of formulations comprising the block copolymers proceed at slightly lower torque and slightly lower temperature than with prior art block copolymers.