Ultrahigh melt flow styrenic block copolymers

US11279821B2 · kind B2 · utility

Assignee

• KRATON POLYMERS LLC · US

Inventors

• John E. Flood · Houston, US
• Xavier Muyldermans · Court-Saint-Etienne, BE

Key dates

• Filing date: Jun 26, 2020
• Grant date: Mar 22, 2022
• Expiry date: Jun 26, 2040

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09J153/025
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A selectively hydrogenated block copolymer of general formula S-E-S, (S-E1)nX, or mixtures thereof is disclosed, where n has a value of 2-6, and X is a coupling agent residue. Before hydrogenation, S is a polystyrene block having a molecular weight of 4,400-5,600 g/mol, and E and E1 are polydiene blocks having molecular weights of 18,000-36,000 g/mol and 9,000 to 18,000 g/mol, respectively, selected from polybutadiene, polyisoprene and mixtures thereof, and having a total vinyl content of 60-85 mol %. After hydrogenation, the block copolymer has 0-10 percent of styrene double bonds reduced and at least 80 percent of conjugated diene double bonds reduced. The block copolymer has a solution viscosity of less than 80 centipoise (cP); a polystyrene content of 25-40 wt. % and up to 50 wt. % of diblock units of general formula S-E or S-E1.