CONDENSED PHASE POLYMERS, METHOD OF MAKING SAME, AND ADHESIVE COMPOSITIONS

The present invention relates to pressure-sensitive adhesive compositions comprising tackified elastomeric copolymers or block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The invention also provides sheet materials coated with the adhesive compositions. The polymers of the present invention are made by a method which comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic-substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers. The resultant elastomeric polymers are compatible with any of a wide variety of known tackifier resins and plasticizers to produce unique pressure-sensitive adhesive compositions.