Shell Oil Comapny

Karel Hendrik Leffelaar

Jeroen Van Westrenen

Jacqueline M Veurink

Hendrik De Groot

Block copolymer compositions, comprising for a major part of linear triblock copolymers, comprising two terminal predominantly poly(monovinylaromatic) blocks having a real molecular weight in the range of from 5,000 to 25,000 and one predominantly poly(boutadiene) midblock, said triblock copolymer having a monovinylaromafic content in the range of from 10 to 55 wt %, an apparent total molecular weight in the range of from 15,000 to 300,000, and an amount of from 0 to 40 wt % of a diblock copolymer relative to the total block copolymer composition weight, containing a predominantly poly(monovinylaromatic) block and a predominantly poly(boutadiene) block similar to those of the triblock copolymer component; said block copolymer composition having a free poly(vinylaromatic) content of at most 7 wt %, and shaped articles derived from said block copolymer composition.

Block copolymers having improved combinations of properties

The invention is a process for the manufacture of six-armed radial asymmetric block copolymers, comprising of the steps of anionically polymerizing first polymer arms, contacting the first polymer arms with a non polymerizable coupling agent containing 6 functional groups, the amount of the first polymer arms being substantially stoichiometrically corresponding to 4 of the functional groups, anionically preparing second polymer arms, different from the first polymer arms, in the same reactor, adding a polar compound capable of increasing the reactivity of the residual functional groups of the coupling agent, reacting these residual functional groups with the second polymers arms, and recovering the asymetric polymer. The asymmetric polymers are useful in adhesive, coating, or sealant compositions and in bitumen blends for roofing, and in sound deadening or vibration dampening compositions.

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Amsterdam, Netherlands

Karel Hendrik Leffelaar