Conjugated diene/monovinylarene block copolymers with multiple tapered blocks

U.S. Patent Number: 5393838

Abstract: A method for preparing polymodal tapered block copolymers in a polymerization process by sequentially charging: (a) an initiator and monovinylaromatic monomers in the presence of a randomizer; (b) an initiator and monovinylaromatic monomers; (c) a mixture of monovinylaromatic and conjugated diene monomers; (d) a mixture of monovinylaromatic and conjugated diene monomers; (e) an initiator and monovinylaromatic monomers; (f) a mixture of monovinylaromatic and conjugated diene monomers; (g) a mixture of monovinylaromatic and conjugated diene monomers; (h) conjugated diene monomers; and (i) a coupling agent. The copolymers and blends thereof are particularly useful for packaging applications which require good environmental stress crack resistance.

Inventors: Moczygemba; George A. (Bartlesville, OK), Stacy; Nathan E. (Bartlesville, OK), Knight; Nancy R. (Ochelata, OK)

Assignee: Phillips Petroleum Company (Bartlesville, OK)

Application Number: 08/163,785

Issued: 1995-02-28

Expired: 2007-02-28

Classes: 525/98 ; 525/314

Field of search: 525/314,95,98

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