Tapered block copolymers of monovinylarenes and conjugated dienes

• Main Authors: TREPKA, WILLIAM, J, MOCZYGEMBA, GEORGE, A, KNIGHT, NANCY, R, STACY, NATHAN, E
• Format: Patent
• Language: English
• Published: 20.06.2000
• Edition: 7
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

A copolymer is prepd. in a reaction zone by: (a) introducing a monovinylaromatic monomer and an initiator in the presence of a randomiser and polymerising until no free monomer is present; (b) adding an initiator and a monovinylaromatic monomer and polymerising until no free monomer is present; (c) adding a mixt. of monovinylaromatic monomer and conjugated diene and polymerising until no free monomer is present; (d) adding a mixt. of monovinylaromatic monomer and conjugated diene monomer and polymerising until no free monomer is present; (e) adding a conjugated diene monomer and allowing complete polymerisation to occur until no free monomer is present; and (f) adding a coupling agent. Only two initiator charges are present and are added in steps (a) and (b). Also claimed are (i) polymodal copolymers produced by the method; (ii)-articles made from the copolymers, and (ii) a polymodal coupled block copolymer having chains resulting from coupling; S-S-B/S-B/S-B-Li S-B/S-B/S-B-Li S = monovinyl aromatic block; B = conjugated diene block; B/S = tapered B and S block; and Li = living polymer or coupling site.