Abstract: Process for manufacturing block copolymers derived from predominantly styrene and predominantly isoprene, used in the form of an isoprene concentrate obtainable by contacting an isoprene concentrate, obtainable by removal of piperylene from a gasoline pyrrolysis fraction of hydrocarbons having 5 carbon atoms, with finely dispersed alkali metal and/or alkaline earth metal, and separating it from the free and bound metal, said process comprising at least the steps of polymerizing predominantly styrene monomer in an inert non-aromatic hydrocarbon solvent in the presence of a monofunctional organolithium initiator, adding predominantly isoprene monomer in the form of pretreated isoprene concentrate to the polymerization mixture, either adding a coupling agent to couple a predominant part of the living diblock copolymer or adding a second portion of predominantly styrene monomer, and adding a terminating agent.

Abstract: A block copolymer composition comprising:(a) 100 parts by weight of a linear block copolymer comprising two polystyrene endblocks and one poly(conjugated diene) midblock, which block copolymer is obtained via a coupling reaction using a diglycidyloxy coupling agent and which block copolymer has a styrene content in the range of from 10 to 50% by weight based on the total weight of block copolymer and an apparent molecular weight in the range of from 100,000 to 400,000; and(b) 0.1 to 2 parts by weight of a stabilizer package consisting of:(b1) 6-(4-hydroxy-3,5-di-t-butylanilino)-2,4-bis-octylthio-1,3,5-triazine, and(b2) a tris-(nonylated phenyl) phosphite, in a weight ratio b1/b2 in the range of from 0.5 to 0.1.The block copolymer composition can be suitably applied in hot melt adhesive compositions.

Abstract: A process is provided for preparing block copolymer blend compositions, which process comprises the subsequent steps of polymerizing vinyl aromatic monomer, adding conjugated diene monomer to the polymerization mixture, adding more initiator, adding of a second portion of conjugated diene monomer, adding a second portion of vinyl aromatic monomer, and adding a terminating agent. A block copolymer composition is provided having a blend of a triblock copolymer A-B-B'-A' and a diblock copolymer B'-A'.

Abstract: An improved continuous process for preparing bisphenols from phenols and carbonyl compounds in the presence of an acidic ion-exchange resin is described wherein the reaction zone comprises at least two reactors in series and a part the effluent from at least one reactor, with the exception of the last reactor, is recycled.